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Sample records for isokinetic contractions isokinetic

  1. Isokinetic leg strength and power in elite handball players.

    Science.gov (United States)

    González-Ravé, José M; Juárez, Daniel; Rubio-Arias, Jacobo A; Clemente-Suarez, Vicente J; Martinez-Valencia, María A; Abian-Vicen, Javier

    2014-06-28

    Isokinetic strength evaluation of the knee flexion and extension in concentric mode of contraction is an important part of the comprehensive evaluation of athletes. The aims of this study were to evaluate the isokinetic knee peak torque in both the extension and flexion movement in the dominant and non-dominant leg, and the relationship with jumping performance. Twelve elite male handball players from the top Spanish handball division voluntary participated in the study (age 27.68 ± 4.12 years; body mass 92.89 ± 12.34 kg; body height 1.90 ± 0.05 m). The knee extensor and flexor muscle peak torque of each leg were concentrically measured at 60º/s and 180º/s with an isokinetic dynamometer. The Squat Jump and Countermovement Jump were performed on a force platform to determine power and vertical jump height. Non-significant differences were observed between legs in the isokinetic knee extension (dominant= 2.91 ± 0.53 Nm/kg vs non-dominant = 2.70 ± 0.47 Nm/kg at 60º/s; dominant = 1.90 ± 0.31 Nm/kg vs non-dominant = 1.83 ± 0.29 Nm/kg at 180º/s) and flexion peak torques (dominant = 1.76 ± 0.29 Nm/kg vs non-dominant = 1.72 ± 0.39 Nm/kg at 60º/s; dominant = 1.30 ± 0.23 Nm/kg vs non-dominant = 1.27 ± 0.35 Nm/kg at 180º/s). Low and non-significant correlation coefficients were found between the isokinetic peak torques and vertical jumping performance (SJ = 31.21 ± 4.32 cm; CMJ = 35.89 ± 4.20 cm). Similar isokinetic strength was observed between the legs; therefore, no relationship was found between the isokinetic knee flexion and extension peak torques as well as vertical jumping performance in elite handball players.

  2. Isokinetic Leg Strength and Power in Elite Handball Players

    Science.gov (United States)

    González-Ravé, José M.; Juárez, Daniel; Rubio-Arias, Jacobo A.; Clemente-Suarez, Vicente J; Martinez-Valencia, María A; Abian-Vicen, Javier

    2014-01-01

    Isokinetic strength evaluation of the knee flexion and extension in concentric mode of contraction is an important part of the comprehensive evaluation of athletes. The aims of this study were to evaluate the isokinetic knee peak torque in both the extension and flexion movement in the dominant and non-dominant leg, and the relationship with jumping performance. Twelve elite male handball players from the top Spanish handball division voluntary participated in the study (age 27.68 ± 4.12 years; body mass 92.89 ± 12.34 kg; body height 1.90 ± 0.05 m). The knee extensor and flexor muscle peak torque of each leg were concentrically measured at 60º/s and 180º/s with an isokinetic dynamometer. The Squat Jump and Countermovement Jump were performed on a force platform to determine power and vertical jump height. Non-significant differences were observed between legs in the isokinetic knee extension (dominant= 2.91 ± 0.53 Nm/kg vs non-dominant = 2.70 ± 0.47 Nm/kg at 60º/s; dominant = 1.90 ± 0.31 Nm/kg vs non-dominant = 1.83 ± 0.29 Nm/kg at 180º/s) and flexion peak torques (dominant = 1.76 ± 0.29 Nm/kg vs non-dominant = 1.72 ± 0.39 Nm/kg at 60º/s; dominant = 1.30 ± 0.23 Nm/kg vs non-dominant = 1.27 ± 0.35 Nm/kg at 180º/s). Low and non-significant correlation coefficients were found between the isokinetic peak torques and vertical jumping performance (SJ = 31.21 ± 4.32 cm; CMJ = 35.89 ± 4.20 cm). Similar isokinetic strength was observed between the legs; therefore, no relationship was found between the isokinetic knee flexion and extension peak torques as well as vertical jumping performance in elite handball players. PMID:25114749

  3. The reliabilty of isokinetic strength measurement

    OpenAIRE

    Kadlec, Miroslav

    2011-01-01

    Title: Reliability of isometric and isokinetic strength testing in the knee flexion and extension Objectives: To compare the reliability of isometric and isokinetic testing of the knee strength in flexion and extension Methods: I used intraclass correlation coefficient and Pearson's correlation coefficient. Results: I have discovered that the reliability measured on isokinetic and isometric dynamometer is high. Furthermore the reliability of the maximum strength measurement was higher with-us...

  4. The Effects of Multiple-Joint Isokinetic Resistance Training on Maximal Isokinetic and Dynamic Muscle Strength and Local Muscular Endurance

    Science.gov (United States)

    Ratamess, Nicholas A.; Beller, Noah A.; Gonzalez, Adam M.; Spatz, Gregory E.; Hoffman, Jay R.; Ross, Ryan E.; Faigenbaum, Avery D.; Kang, Jie

    2016-01-01

    The transfer of training effects of multiple-joint isokinetic resistance training to dynamic exercise performance remain poorly understood. Thus, the purpose of the present study was to investigate the magnitude of isokinetic and dynamic one repetition-maximum (1RM) strength and local muscular endurance increases after 6 weeks of multiple-joint isokinetic resistance training. Seventeen women were randomly assigned to either an isokinetic resistance training group (IRT) or a non-exercising control group (CTL). The IRT group underwent 6 weeks of training (2 days per week) consisting of 5 sets of 6-10 repetitions at 75-85% of subjects’ peak strength for the isokinetic chest press and seated row exercises at an average linear velocity of 0.15 m s-1 [3-sec concentric (CON) and 3-sec eccentric (ECC) phases]. Peak CON and ECC force during the chest press and row, 1RM bench press and bent-over row, and maximum number of modified push-ups were assessed pre and post training. A 2 x 2 analysis of variance with repeated measures and Tukey’s post hoc tests were used for data analysis. The results showed that 1RM bench press (from 38.6 ± 6.7 to 43.0 ± 5.9 kg), 1RM bent-over row (from 40.4 ± 7.7 to 45.5 ± 7.5 kg), and the maximal number of modified push-ups (from 39.5 ± 13.6 to 55.3 ± 13.1 repetitions) increased significantly only in the IRT group. Peak isokinetic CON and ECC force in the chest press and row significantly increased in the IRT group. No differences were shown in the CTL group for any measure. These data indicate 6 weeks of multiple-joint isokinetic resistance training increases dynamic muscle strength and local muscular endurance performance in addition to specific isokinetic strength gains in women. Key points Multiple-joint isokinetic resistance training increases dynamic maximal muscular strength, local muscular endurance, and maximal isokinetic strength in women. Multiple-joint isokinetic resistance training increased 1RM strength in the bench press

  5. The Effects of Multiple-Joint Isokinetic Resistance Training on Maximal Isokinetic and Dynamic Muscle Strength and Local Muscular Endurance.

    Science.gov (United States)

    Ratamess, Nicholas A; Beller, Noah A; Gonzalez, Adam M; Spatz, Gregory E; Hoffman, Jay R; Ross, Ryan E; Faigenbaum, Avery D; Kang, Jie

    2016-03-01

    The transfer of training effects of multiple-joint isokinetic resistance training to dynamic exercise performance remain poorly understood. Thus, the purpose of the present study was to investigate the magnitude of isokinetic and dynamic one repetition-maximum (1RM) strength and local muscular endurance increases after 6 weeks of multiple-joint isokinetic resistance training. Seventeen women were randomly assigned to either an isokinetic resistance training group (IRT) or a non-exercising control group (CTL). The IRT group underwent 6 weeks of training (2 days per week) consisting of 5 sets of 6-10 repetitions at 75-85% of subjects' peak strength for the isokinetic chest press and seated row exercises at an average linear velocity of 0.15 m s(-1) [3-sec concentric (CON) and 3-sec eccentric (ECC) phases]. Peak CON and ECC force during the chest press and row, 1RM bench press and bent-over row, and maximum number of modified push-ups were assessed pre and post training. A 2 x 2 analysis of variance with repeated measures and Tukey's post hoc tests were used for data analysis. The results showed that 1RM bench press (from 38.6 ± 6.7 to 43.0 ± 5.9 kg), 1RM bent-over row (from 40.4 ± 7.7 to 45.5 ± 7.5 kg), and the maximal number of modified push-ups (from 39.5 ± 13.6 to 55.3 ± 13.1 repetitions) increased significantly only in the IRT group. Peak isokinetic CON and ECC force in the chest press and row significantly increased in the IRT group. No differences were shown in the CTL group for any measure. These data indicate 6 weeks of multiple-joint isokinetic resistance training increases dynamic muscle strength and local muscular endurance performance in addition to specific isokinetic strength gains in women. Key pointsMultiple-joint isokinetic resistance training increases dynamic maximal muscular strength, local muscular endurance, and maximal isokinetic strength in women.Multiple-joint isokinetic resistance training increased 1RM strength in the bench press (by

  6. Isokinetic Evaluation of the Hip Flexor and Extensor Muscles: A Systematic Review.

    Science.gov (United States)

    Zapparoli, Fabricio Yuri; Riberto, Marcelo

    2017-11-01

    Isokinetic dynamometry testing is a safe and reliable method accepted as the "gold standard" in the evaluation of muscle strength in the open kinetic chain. Isokinetic hip examinations face problems in the standardization of the position of the equipment axis, in the individual being examined, and in the adjustment of the lever arm and in stabilization strategies for the patients during the tests. Identification of the methodologic procedures with best reproducibility is also needed. To review the literature to evaluate the parameters used for the isokinetic evaluation of the hip flexor and extensor muscles and its reproducibility. This is a systematic literature review of the Cochrane, LILACS, PEDro, PubMed, and SciELO databases. The inclusion criteria were articles on the evaluation of hip flexor and/or extensor muscular strength with an isokinetic dynamometer and articles that analyzed the ICC or Pearson's reproducibility. The information extracted was positioning of the patient; positioning of the dynamometer axis; positioning of the lever arm; angular speed; sample size, pathology; type of contraction; and ICC and Pearson's results. 204 articles were found, from which 14 were selected that evaluated hip flexor and extensor muscles, involving 550 individuals who were submitted to an isokinetic hip evaluation. Five articles obtained the best result in reproducibility and had their methodology analyzed. To obtain better reproducibility of the isokinetic evaluation of the hip flexor and extensor muscles, the following recommendations must be followed: the individual must be positioned in the supine position and the dynamometer axis must be aligned with the greater trochanter of the femur. The positioning of the lever arm must be in the most distal region of the thigh possible. The angular speed used to analyze torque peak and muscle work was 60°/s, and to evaluate the muscle power it was 180°/s, with concentric and eccentric contractions being analyzed.

  7. The Effects of Multiple-Joint Isokinetic Resistance Training on Maximal Isokinetic and Dynamic Muscle Strength and Local Muscular Endurance

    Directory of Open Access Journals (Sweden)

    Nicholas A. Ratamess, Noah A. Beller, Adam M. Gonzalez, Gregory E. Spatz, Jay R. Hoffman, Ryan E. Ross, Avery D. Faigenbaum, Jie Kang

    2016-03-01

    Full Text Available The transfer of training effects of multiple-joint isokinetic resistance training to dynamic exercise performance remain poorly understood. Thus, the purpose of the present study was to investigate the magnitude of isokinetic and dynamic one repetition-maximum (1RM strength and local muscular endurance increases after 6 weeks of multiple-joint isokinetic resistance training. Seventeen women were randomly assigned to either an isokinetic resistance training group (IRT or a non-exercising control group (CTL. The IRT group underwent 6 weeks of training (2 days per week consisting of 5 sets of 6-10 repetitions at 75-85% of subjects’ peak strength for the isokinetic chest press and seated row exercises at an average linear velocity of 0.15 m s-1 [3-sec concentric (CON and 3-sec eccentric (ECC phases]. Peak CON and ECC force during the chest press and row, 1RM bench press and bent-over row, and maximum number of modified push-ups were assessed pre and post training. A 2 x 2 analysis of variance with repeated measures and Tukey’s post hoc tests were used for data analysis. The results showed that 1RM bench press (from 38.6 ± 6.7 to 43.0 ± 5.9 kg, 1RM bent-over row (from 40.4 ± 7.7 to 45.5 ± 7.5 kg, and the maximal number of modified push-ups (from 39.5 ± 13.6 to 55.3 ± 13.1 repetitions increased significantly only in the IRT group. Peak isokinetic CON and ECC force in the chest press and row significantly increased in the IRT group. No differences were shown in the CTL group for any measure. These data indicate 6 weeks of multiple-joint isokinetic resistance training increases dynamic muscle strength and local muscular endurance performance in addition to specific isokinetic strength gains in women.

  8. Isokinetic and isometric muscle strength combined with transcutaneous electrical muscle stimulation in primary fibromyalgia syndrome

    DEFF Research Database (Denmark)

    Jacobsen, Søren; Wildschiødtz, Gordon; Danneskiold-Samsøe, B

    1991-01-01

    Twenty women with primary fibromyalgia syndrome and 20 age matched healthy women were investigated. The subjects performed maximum voluntary isokinetic contractions of the right quadriceps in an isokinetic dynamometer. Maximum voluntary isometric contractions of the right quadriceps were performed...... of superimposed twitches was 65% in the patient group and 15% in the control group (p = 0.003). Patients with primary fibromyalgia have a lower maximum voluntary muscle strength than expected. The increased presence of superimposed electrically elicited twitches during maximum voluntary contraction indicates...... submaximal force application in primary fibromyalgia syndrome....

  9. Isokinetic Testing in Evaluation Rehabilitation Outcome After ACL Reconstruction.

    Science.gov (United States)

    Cvjetkovic, Dragana Dragicevic; Bijeljac, Sinisa; Palija, Stanislav; Talic, Goran; Radulovic, Tatjana Nozica; Kosanovic, Milkica Glogovac; Manojlovic, Slavko

    2015-02-01

    Numerous rehab protocols have been used in rehabilitation after ACL reconstruction. Isokinetic testing is an objective way to evaluate dynamic stability of the knee joint that estimates the quality of rehabilitation outcome after ACL reconstruction. Our investigation goal was to show importance of isokinetic testing in evaluation thigh muscle strength in patients which underwent ACL reconstruction and rehabilitation protocol. In prospective study, we evaluated 40 subjects which were divided into two groups. Experimental group consisted of 20 recreational males which underwent ACL reconstruction with hamstring tendon and rehabilitation protocol 6 months before isokinetic testing. Control group (20 subjects) consisted of healthy recreational males. In all subjects knee muscle testing was performed on a Biodex System 4 Pro isokinetic dynamo-meter et velocities of 60°/s and 180°/s. We followed average peak torque to body weight (PT/BW) and classic H/Q ratio. In statistical analysis Student's T test was used. There were statistically significant differences between groups in all evaluated parameters except of the mean value of PT/BW of the quadriceps et velocity of 60°/s (p>0.05). Isokinetic testing of dynamic stabilizers of the knee is need in diagnostic and treatment thigh muscle imbalance. We believe that isokinetic testing is an objective parameter for return to sport activities after ACL reconstruction.

  10. Comparison of isokinetic and isometric strength training effects on hamstring and quadriceps torques and physical function in knee pain

    International Nuclear Information System (INIS)

    Masood, T.; Khan, H.M.M.H.

    2017-01-01

    To compare the effects of isokinetic and isometric strength trainings on hamstring and quadriceps average-peak-torques, physical performance, and pain. Methodology: Twenty athletes with knee pain were randomly assigned to two equal groups: Isokinetic training and isometric training. Both groups were trained on Biodex System 3 Pro for 10 sessions. Isokinetic-group received isokinetic training on 5 different velocities while isometric-group performed isometric contractions at 3 knee joint angles. Results: Hamstring isokinetic average-peak-torque was significantly higher at all velocities without significant improvement in quadriceps average-peak-torque except for at the slowest velocity. Isometric training did not cause significant change in isometric average-peak-torque at any knee angle for either hamstring or quadriceps. Agility, elastic leg strength, and pain improved significantly in both groups with no significant between-group differences. No significant statistical correlation was observed between pain and any other parameter after either type of training. Conclusions: Athletes participating in sports requiring dynamic hamstring strength should prefer isokinetic strength training for physical rehabilitation of knee pain. However, physical performance and pain can be improved with both isometric and isokinetic strength training. (author)

  11. Neuromuscular and muscle-tendon system adaptations to isotonic and isokinetic eccentric exercise.

    Science.gov (United States)

    Guilhem, G; Cornu, C; Guével, A

    2010-06-01

    To present the properties of an eccentric contraction and compare neuromuscular and muscle-tendon system adaptations induced by isotonic and isokinetic eccentric trainings. An eccentric muscle contraction is characterized by the production of muscle force associated to a lengthening of the muscle-tendon system. This muscle solicitation can cause micro lesions followed by a regeneration process of the muscle-tendon system. Eccentric exercise is commonly used in functional rehabilitation for its positive effect on collagen synthesis but also for resistance training to increase muscle strength and muscle mass in athletes. Indeed, eccentric training stimulates muscle hypertrophy, increases the fascicle pennation angle, fascicles length and neural activation, thus inducing greater strength gains than concentric or isometric training programs. Eccentric exercise is commonly performed either against a constant external load (isotonic) or at constant velocity (isokinetic), inducing different mechanical constraints. These different mechanical constraints could induce structural and neural adaptive strategies specific to each type of exercise. The literature tends to show that isotonic mode leads to a greater strength gain than isokinetic mode. This observation could be explained by a greater neuromuscular activation after IT training. However, the specific muscle adaptations induced by each mode remain difficult to determine due to the lack of standardized, comparative studies. 2010 Elsevier Masson SAS. All rights reserved.

  12. Combined effects of myofeedback and isokinetic training on hand ...

    African Journals Online (AJOL)

    Combined effects of myofeedback and isokinetic training on hand function in spastic hemiplegic children. ... Both groups received a designed physical therapy program with isokinetic training for the triceps brachii muscle for 60 min, in addition group B received myofeedback training. Results: The post treatment results ...

  13. Isometric and isokinetic hip strength and agonist/antagonist ratios in symptomatic femoroacetabular impingement.

    Science.gov (United States)

    Diamond, Laura E; Wrigley, Tim V; Hinman, Rana S; Hodges, Paul W; O'Donnell, John; Takla, Amir; Bennell, Kim L

    2016-09-01

    This study investigated isometric and isokinetic hip strength in individuals with and without symptomatic femoroacetabular impingement (FAI). The specific aims were to: (i) determine whether differences exist in isometric and isokinetic hip strength measures between groups; (ii) compare hip strength agonist/antagonist ratios between groups; and (iii) examine relationships between hip strength and self-reported measures of either hip pain or function in those with FAI. Cross-sectional. Fifteen individuals (11 males; 25±5 years) with symptomatic FAI (clinical examination and imaging (alpha angle >55° (cam FAI), and lateral centre edge angle >39° and/or positive crossover sign (combined FAI))) and 14 age- and sex-matched disease-free controls (no morphological FAI on magnetic resonance imaging) underwent strength testing. Maximal voluntary isometric contraction strength of hip muscle groups and isokinetic hip internal (IR) and external rotation (ER) strength (20°/s) were measured. Groups were compared with independent t-tests and Mann-Whitney U tests. Participants with FAI had 20% lower isometric abduction strength than controls (p=0.04). There were no significant differences in isometric strength for other muscle groups or peak isokinetic ER or IR strength. The ratio of isometric, but not isokinetic, ER/IR strength was significantly higher in the FAI group (p=0.01). There were no differences in ratios for other muscle groups. Angle of peak IR torque was the only feature correlated with symptoms. Individuals with symptomatic FAI demonstrate isometric hip abductor muscle weakness and strength imbalance in the hip rotators. Strength measurement, including agonist/antagonist ratios, may be relevant for clinical management of FAI. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  14. Isokinetic Extension Strength Is Associated With Single-Leg Vertical Jump Height.

    Science.gov (United States)

    Fischer, Felix; Blank, Cornelia; Dünnwald, Tobias; Gföller, Peter; Herbst, Elmar; Hoser, Christian; Fink, Christian

    2017-11-01

    Isokinetic strength testing is an important tool in the evaluation of the physical capacities of athletes as well as for decision making regarding return to sports after anterior cruciate ligament (ACL) reconstruction in both athletes and the lay population. However, isokinetic testing is time consuming and requires special testing equipment. A single-jump test, regardless of leg dominance, may provide information regarding knee extension strength through the use of correlation analysis of jump height and peak torque of isokinetic muscle strength. Cross-sectional study; Level of evidence, 3. A total of 169 patients who underwent ACL reconstruction were included in this study. Isokinetic testing was performed on the injured and noninjured legs. Additionally, a single-leg countermovement jump was performed to assess jump height using a jump accelerometer sensor. Extension strength values were used to assess the association between isokinetic muscle strength and jump height. The sample consisted of 60 female (mean age, 20.8 ± 8.3 years; mean weight, 61.7 ± 6.5 kg; mean height, 167.7 ± 5.3 cm) and 109 male (mean age, 23.2 ± 7.7 years; mean weight, 74.6 ± 10.2 kg; mean height, 179.9 ± 6.9 cm) patients. Bivariate correlation analysis showed an association ( r = 0.56, P jump height and isokinetic extension strength on the noninvolved side as well as an association ( r = 0.52, P jump height (beta = 0.49, P jump height having the strongest impact (beta = 0.49, P jump height. The study population encompassed various backgrounds, skill levels, and activity profiles, which might have affected the outcome. Even after controlling for age and sex, isokinetic strength was still moderately associated with jump height. Therefore, the jump technique and type of sport should be considered in future research.

  15. Isokinetic Testing in Evaluation Rehabilitation Outcome After ACL Reconstruction

    OpenAIRE

    Cvjetkovic, Dragana Dragicevic; Bijeljac, Sinisa; Palija, Stanislav; Talic, Goran; Radulovic, Tatjana Nozica; Kosanovic, Milkica Glogovac; Manojlovic, Slavko

    2015-01-01

    Introduction: Numerous rehab protocols have been used in rehabilitation after ACL reconstruction. Isokinetic testing is an objective way to evaluate dynamic stability of the knee joint that estimates the quality of rehabilitation outcome after ACL reconstruction. Our investigation goal was to show importance of isokinetic testing in evaluation thigh muscle strength in patients which underwent ACL reconstruction and rehabilitation protocol. Subjects and methods: In prospective study, we evalua...

  16. Efficacy of isokinetic exercise on functional capacity and pain in patellofemoral pain syndrome.

    Science.gov (United States)

    Alaca, Ridvan; Yilmaz, Bilge; Goktepe, A Salim; Mohur, Haydar; Kalyon, Tunc Alp

    2002-11-01

    To assess the effect of an isokinetic exercise program on symptoms and functions of patients with patellofemoral pain syndrome. A total of 22 consecutive patients with the complaint of anterior knee pain who met the inclusion criteria were recruited to assess the efficacy of isokinetic exercise on functional capacity, isokinetic parameters, and pain scores in patients with patellofemoral pain syndrome. A total of 37 knees were examined. Six-meter hopping, three-step hopping, and single-limb hopping course tests were performed for each patient with the measurements of the Lysholm scale and visual analog scale. Tested parameters were peak torque, total work, average power, and endurance ratios. Statistical analyses revealed that at the end of the 6-wk treatment period, functional and isokinetic parameters improved significantly, as did pain scores. There was not statistically significant correlation between different groups of parameters. The isokinetic exercise treatment program used in this study prevented the extensor power loss due to patellofemoral pain syndrome, but the improvement in the functional capacity was not correlated with the gained power.

  17. Test-Retest Reliability of Isokinetic Knee Strength Measurements in Children Aged 8 to 10 Years.

    Science.gov (United States)

    Fagher, Kristina; Fritzson, Annelie; Drake, Anna Maria

    Isokinetic dynamometry is a useful tool to objectively assess muscle strength of children and adults in athletic and rehabilitative settings. This study examined test-retest reliability of isokinetic knee strength measurements in children aged 8 to 10 years and defined limits for the minimum difference (MD) in strength that indicates a clinically important change. Isokinetic knee strength measurements (using the Biodex System 4) in children will provide reliable results. Descriptive laboratory study. In 22 healthy children, 5 maximal concentric (CON) knee extensor (KE) and knee flexor (KF) contractions at 2 angular velocities (60 deg/s and 180 deg/s) and 5 maximal eccentric (ECC) KE/KF contractions at 60 deg/s were assessed 7 days apart. The intraclass correlation coefficient (ICC 2.1 ) was used to examine relative reliability, and the MD was calculated on the basis of standard error of measurement. ICCs for CON KE/KF peak torque measurements were fair to excellent (range, 0.49-0.81). The MD% values for CON KE and KF ranged from 31% to 37% at 60 deg/s and from 34% to 39% at 180 deg/s. ICCs in the ECC mode were good (range, 0.60-0.70), but associated MD% values were high (>50%). There was no systematic error for CON KE/KF and ECC KE strength measurements at 60 deg/s, but systematic error was found for all other measurements. The dynamometer provides a reliable analysis of isokinetic CON knee strength measurements at 60 deg/s in children aged 8 to 10 years. Measurements at 180 deg/s and in the ECC mode were not reliable, indicating a need for more familiarization prior to testing. The MD values may help clinicians to determine whether a change in knee strength is due to error or intervention.

  18. Isokinetic Strength and Endurance Tests used Pre- and Post-Spaceflight: Test-Retest Reliability

    Science.gov (United States)

    Laughlin, Mitzi S.; Lee, Stuart M. C.; Loehr, James A.; Amonette, William E.

    2009-01-01

    To assess changes in muscular strength and endurance after microgravity exposure, NASA measures isokinetic strength and endurance across multiple sessions before and after long-duration space flight. Accurate interpretation of pre- and post-flight measures depends upon the reliability of each measure. The purpose of this study was to evaluate the test-retest reliability of the NASA International Space Station (ISS) isokinetic protocol. Twenty-four healthy subjects (12 M/12 F, 32.0 +/- 5.6 years) volunteered to participate. Isokinetic knee, ankle, and trunk flexion and extension strength as well as endurance of the knee flexors and extensors were measured using a Cybex NORM isokinetic dynamometer. The first weekly session was considered a familiarization session. Data were collected and analyzed for weeks 2-4. Repeated measures analysis of variance (alpha=0.05) was used to identify weekly differences in isokinetic measures. Test-retest reliability was evaluated by intraclass correlation coefficients (ICC) (3,1). No significant differences were found between weeks in any of the strength measures and the reliability of the strength measures were all considered excellent (ICC greater than 0.9), except for concentric ankle dorsi-flexion (ICC=0.67). Although a significant difference was noted in weekly endurance measures of knee extension (p less than 0.01), the reliability of endurance measure by week were considered excellent for knee flexion (ICC=0.97) and knee extension (ICC=0.96). Except for concentric ankle dorsi-flexion, the isokinetic strength and endurance measures are highly reliable when following the NASA ISS protocol. This protocol should allow accurate interpretation isokinetic data even with a small number of crew members.

  19. Muscle recruitment patterns of the subscapularis, serratus anterior and other shoulder girdle muscles during isokinetic internal and external rotations.

    Science.gov (United States)

    Gaudet, Sylvain; Tremblay, Jonathan; Begon, Mickael

    2018-05-01

    The aims of this study were to investigate the differences in peak muscle activity and recruitment patterns during high- and low-velocity, concentric and eccentric, internal and external isokinetic shoulder rotations. Electromyographic activity of the rotator cuff and eight superficial muscles of the shoulder girdle was recorded on 25 healthy adults during isokinetic internal and external shoulder rotation at 60°/s and 240°/s. Peak muscle activity, electromyographic envelopes and peak isokinetic moments were analyzed using three-factor ANOVA and statistical parametric mapping. The subscapularis and serratus anterior showed moderate to high peak activity levels during each conditions, while the middle and posterior deltoids, upper, middle and lower trapezius, infraspinatus and supraspinatus showed higher peak activity levels during external rotations (+36.5% of maximum voluntary activation (MVA)). The pectoralis major and latissimus dorsi were more active during internal rotations (+40% of MVA). Only middle trapezius and pectoralis major electromyographic activity decreased with increasing velocity. Peak muscle activity was similar or lower during eccentric contractions, although the peak isokinetic moment increased by 35% on average. The subscapularis and serratus anterior appear to be important stabilizers of the glenohumeral joint and scapula. Isokinetic eccentric training at high velocities may allow for faster recruitment of the shoulder girdle muscles, which could improve joint stability during shoulder internal and external rotations.

  20. Hyperventilation-induced respiratory alkalosis falls short of countering fatigue during repeated maximal isokinetic contractions.

    Science.gov (United States)

    Sakamoto, Akihiro; Naito, Hisashi; Chow, Chin Moi

    2015-07-01

    Hyperventilation, implemented during recovery of repeated maximal sprints, has been shown to attenuate performance decrement. This study evaluated the effects of hyperventilation, using strength exercises, on muscle torque output and EMG amplitude. Fifteen power-trained athletes underwent maximal isokinetic knee extensions consisting of 12 repetitions × 8 sets at 60°/s and 25 repetitions × 8 sets at 300°/s. The inter-set interval was 40 s for both speeds. For the control condition, subjects breathed spontaneously during the interval period. For the hyperventilation condition, subjects hyperventilated for 30 s before each exercise set (50 breaths/min, PETCO2: 20-25 mmHg). EMG was recorded from the vastus medialis and lateralis muscles to calculate the mean amplitude for each contraction. Hyperventilation increased blood pH by 0.065-0.081 and lowered PCO2 by 8.3-10.3 mmHg from the control values (P < 0.001). Peak torque declined with repetition and set numbers for both speeds (P < 0.001), but the declining patterns were similar between conditions. A significant, but small enhancement in peak torque was observed with hyperventilation at 60°/s during the initial repetition phase of the first (P = 0.032) and fourth sets (P = 0.040). EMG amplitude also declined with set number (P < 0.001) for both speeds and muscles, which was, however, not attenuated by hyperventilation. Despite a minor ergogenic effect in peak torque at 60°/s, hyperventilation was not effective in attenuating the decrement in torque output at 300°/s and decrement in EMG amplitude at both speeds during repeated sets of maximal isokinetic knee extensions.

  1. Selected isokinetic tests in knee injury prevention

    Directory of Open Access Journals (Sweden)

    W Pilis

    2010-03-01

    Full Text Available Ensuing from isokinetic measurements, the conventional Hcon/Qcon ratio of muscle balance is used as an index for comparing proper relations between the values of strength of knee flexors and extensor muscle. Its abnormal values might indicate pathology of the musculotendinous complex. The aim of the study was to present the possibility of using this ratio as one of the objective identifiers enabling the assessment of knee injury risk in sports. All participants (n=48 were divided into 3 groups: group A (n=16, healthy competitors, group B (n=16, athletes with minor injuries, group C (n=16, competitors with serious injuries, depending on the degree of knee injury. All subjects performed an isokinetic test for knee extensors and flexors at angular velocities of 60°/s and 120°/s. Average peak torque (APT value of knee flexors and extensors, and the value of Hcon/Qcon ratio was analyzed. Both values were calculated in relation to body mass (Nm/kg. Bilateral comparison of isokinetic test parameters confirmed the decrease of quadriceps muscle strength values for the injured extremity in groups B and C. Statistically significant difference was noted for Hcon/Qcon ratio between group A and C, as well as B and C. Hence, the value of conventional Hcon/Qcon ratio can be used for the prevention of sports related injuries.

  2. INTERSESSION RELIABILITY OF UPPER EXTREMITY ISOKINETIC PUSH-PULL TESTING.

    Science.gov (United States)

    Riemann, Bryan L; Davis, Sarah E; Huet, Kevin; Davies, George J

    2016-02-01

    Based on the frequency pushing and pulling patterns are used in functional activities, there is a need to establish an objective method of quantifying the muscle performance characteristics associated with these motions, particularly during the later stages of rehabilitation as criteria for discharge. While isokinetic assessment offers an approach to quantifying muscle performance, little is known about closed kinetic chain (CKC) isokinetic testing of the upper extremity (UE). To determine the intersession reliability of isokinetic upper extremity measurement of pushing and pulling peak force and average power at slow (0.24 m/s), medium (0.43 m/s) and fast (0.61 m/s) velocities in healthy young adults. The secondary purpose was to compare pushing and pulling peak force (PF) and average power (AP) between the upper extremity limbs (dominant, non-dominant) across the three velocities. Twenty-four physically active men and women completed a test-retest (>96 hours) protocol in order to establish isokinetic UE CKC reliability of PF and AP during five maximal push and pull repetitions at three velocities. Both limb and speed orders were randomized between subjects. High test-retest relative reliability using intraclass correlation coefficients (ICC2, 1) were revealed for PF (.91-.97) and AP (.85-.95) across velocities, limbs and directions. PF typical error (% coefficient of variation) ranged from 6.1% to 11.3% while AP ranged from 9.9% to 26.7%. PF decreased significantly (p pushing were significantly greater than pulling at all velocities, however the push-pull differences in PF became less as velocity increased. There were no significant differences identified between the dominant and nondominant limbs. Isokinetically derived UE CKC push-pull PF and AP are reliable measures. The lack of limb differences in healthy normal participants suggests that clinicians can consider bilateral comparisons when interpreting test performance. The increase in pushing PF and

  3. Isokinetic strength of shoulder internal and external rotators in cricket bowlers

    Directory of Open Access Journals (Sweden)

    X.M. Mabasa

    2002-02-01

    Full Text Available The strength of the shoulder internal and external rotators incricket bowlers, may not be sufficient to cope with the demands of bowling.As very little research has been done on cricketers, this study was done to establish the isokinetic strength profile of the shoulder internal andexternal rotators in cricket bowlers.Isokinetic, shoulder rotational strength was evaluated in thirty malecricket volunteers with a mean age of 23.9 years and mean body weight of 70.3 kgs. The Cybex 340 dynamometer multi joint system was used to collect data on shoulder rotation strength in a standing neutral position. Data were collected at four different speeds (60,90,180 and 300deg/sec and were computed for peak torque values for internal and external ratios for both dominant and non dominant shoulders.The results showed no statistically significant difference in the mean shoulder rotational torque between the bowlingand non-bowling shoulders for external rotation (p>0.05, and indicated statistically significant differences in themean shoulder rotational torque between the bowling and non-bowling shoulders for internal rotation (p<0.05. Therewas a significant decrease in isokinetic peak torque production for the external/internal rotator muscles as the speedof contraction increased (p<0.05. The peak torque ratio for the external/internal rotator muscles of the bowling armwere significantly less than of the non-bowling arm (p<0.05. These findings suggest that the strength ratios of thebowling arm need to be considered when managing young cricketers and their injuries.

  4. Validity of trunk extensor and flexor torque measurements using isokinetic dynamometry.

    Science.gov (United States)

    Guilhem, Gaël; Giroux, Caroline; Couturier, Antoine; Maffiuletti, Nicola A

    2014-12-01

    This study aimed to evaluate the validity and test-retest reliability of trunk muscle strength testing performed with a latest-generation isokinetic dynamometer. Eccentric, isometric, and concentric peak torque of the trunk flexor and extensor muscles was measured in 15 healthy subjects. Muscle cross sectional area (CSA) and surface electromyographic (EMG) activity were respectively correlated to peak torque and submaximal isometric torque for erector spinae and rectus abdominis muscles. Reliability of peak torque measurements was determined during test and retest sessions. Significant correlations were consistently observed between muscle CSA and peak torque for all contraction types (r=0.74-0.85; Ptorque (r ⩾ 0.99; Ptorque between test and retest ranged from -3.7% to 3.7% with no significant mean directional bias. Overall, our findings establish the validity of torque measurements using the tested trunk module. Also considering the excellent test-retest reliability of peak torque measurements, we conclude that this latest-generation isokinetic dynamometer could be used with confidence to evaluate trunk muscle function for clinical or athletic purposes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. The Advantages of Normalizing Electromyography to Ballistic Rather than Isometric or Isokinetic Tasks.

    Science.gov (United States)

    Suydam, Stephen M; Manal, Kurt; Buchanan, Thomas S

    2017-07-01

    Isometric tasks have been a standard for electromyography (EMG) normalization stemming from anatomic and physiologic stability observed during contraction. Ballistic dynamic tasks have the benefit of eliciting maximum EMG signals for normalization, despite having the potential for greater signal variability. It is the purpose of this study to compare maximum voluntary isometric contraction (MVIC) to nonisometric tasks with increasing degrees of extrinsic variability, ie, joint range of motion, velocity, rate of contraction, etc., to determine if the ballistic tasks, which elicit larger peak EMG signals, are more reliable than the constrained MVIC. Fifteen subjects performed MVIC, isokinetic, maximum countermovement jump, and sprint tasks while EMG was collected from 9 muscles in the quadriceps, hamstrings, and lower leg. The results revealed the unconstrained ballistic tasks were more reliable compared to the constrained MVIC and isokinetic tasks for all triceps surae muscles. The EMG from sprinting was more reliable than the constrained cases for both the hamstrings and vasti. The most reliable EMG signals occurred when the body was permitted its natural, unconstrained motion. These results suggest that EMG is best normalized using ballistic tasks to provide the greatest within-subject reliability, which beneficially yield maximum EMG values.

  6. Effect of isokinetic training on strength, functionality and proprioception in athletes with functional ankle instability.

    Science.gov (United States)

    Sekir, Ufuk; Yildiz, Yavuz; Hazneci, Bulent; Ors, Fatih; Aydin, Taner

    2007-05-01

    The purpose of this study was to investigate the effects of isokinetic exercise on strength, joint position sense and functionality in recreational athletes with functional ankle instability (FAI). Strength, proprioception and balance of 24 recreational athletes with unilateral FAI were evaluated by using isokinetic muscle strength measurement, ankle joint position sense and one leg standing test. The functional ability was evaluated using five different tests. These were; single limb hopping course (SLHC), one legged and triple legged hop for distance (OLHD-TLHD), and six and cross six meter hop for time (SMHT-CSMHT). Isokinetic peak torque of the ankle invertor and evertor muscles were assessed eccentrically and concentrically at test speeds of 120 degrees /s. Isokinetic exercise protocol was carried out at an angular velocity of 120 degrees /s. The exercise session was repeated three times a week and lasted after 6 weeks. At baseline, concentric invertor strength was found to be significantly lower in the functionally unstable ankles compared to the opposite healthy ankles (p 0.05). Ankle joint position sense in the injured ankles declined significantly from 2.35 +/- 1.16 to 1.33 +/- 0.62 degrees for 10 degrees of inversion angle (p isokinetic exercise. One leg standing test score decreased significantly from 15.17 +/- 8.50 to 11.79 +/- 7.81 in the injured ankles (p isokinetic exercise protocol, all of the worsened functional test scores in the injured ankles as compared to the opposite healthy ankles displayed a significant improvement (p isokinetic exercise program used in this study had a positive effect on these parameters.

  7. Relation between isokinetic muscle strength and functional capacity in recreational athletes with chondromalacia patellae.

    Science.gov (United States)

    Yildiz, Y; Aydin, T; Sekir, U; Cetin, C; Ors, F; Alp Kalyon, T

    2003-12-01

    To investigate the effects of isokinetic exercise on pain and functional test scores of recreational athletes with chondromalacia patellae (CMP) and to examine the correlation between isokinetic parameters and functional tests or pain score. The functional ability of 30 recreational athletes with unilateral CMP was evaluated using six different tests. Pain scores were assessed during daily activities before and after the treatment protocol. Isokinetic exercise sessions were carried out at angular velocities of 60 degrees /s (25-90 degrees range of flexion) and 180 degrees /s (full range). These sessions were repeated three times a week for six weeks. Quadriceps and hamstring peak torque, total work, and endurance ratios had improved significantly after the treatment, as did the functional parameters and pain scores. There was a poor correlation between the extensor endurance ratio and one leg standing test. A moderate correlation between the visual analogue scale and the extensor endurance ratio or flexion endurance ratio was also found. The isokinetic exercise programme used in this study had a positive effect on muscle strength, pain score, and functional ability of knees with CMP. The improvement in the functional capacity did not correlate with the isokinetic parameters.

  8. Effects of Motor Learning on Clinical Isokinetic Test Performance in Knee Osteoarthritis Patients

    Directory of Open Access Journals (Sweden)

    José Messias Rodrigues-da-Silva

    Full Text Available OBJECTIVES: To analyze the effects of motor learning on knee extension-flexion isokinetic performance in knee osteoarthritis patients. METHODS: One hundred and thirty-six middle-aged and older sedentary individuals (111 women, 64.3±9.9 years with knee osteoarthritis (130 patients with bilateral and who had never performed isokinetic testing underwent two bilateral knee extension-flexion (concentric-concentric isokinetic evaluations (5 repetitions at 60°/sec. The tests were first performed on the dominant leg with 2 min of recovery between test, and following a standardized warm-up that included 3 submaximal isokinetic repetitions. The same procedure was repeated on the non-dominant leg. The peak torque, peak torque adjusted for the body weight, total work, coefficient of variation and agonist/antagonist ratio were compared between tests. RESULTS: Patients showed significant improvements in test 2 compared to test 1, including higher levels of peak torque, peak torque adjusted for body weight and total work, as well as lower coefficients of variation. The agonist/antagonist relationship did not significantly change between tests. No significant differences were found between the right and left legs for all variables. CONCLUSION: The results suggest that performing two tests with a short recovery (2 min between them could be used to reduce motor learning effects on clinical isokinetic testing of the knee joint in knee osteoarthritis patients.

  9. Isokinetic evaluation of knee muscles in soccer players: discriminant analysis

    Directory of Open Access Journals (Sweden)

    Bruno Fles Mazuquin

    2015-10-01

    Full Text Available ABSTRACTIntroduction:Muscle activity in soccer players can be measured by isokinetic dynamometer, which is a reliable tool for assessing human performance.Objectives:To perform isokinetic analyses and to determine which variables differentiate the under-17 (U17 soccer category from the professional (PRO.Methods:Thirty four players were assessed (n=17 for each category. The isokinetic variables used for the knee extension-flexion analysis were: peak torque (Nm, total work (J, average power (W, angle of peak torque (deg., agonist/ antagonist ratio (%, measured for three velocities (60°/s, 120°/s and 300°/s, with each series containing five repetitions. Three Wilks' Lambda discriminant analyses were performed, to identify which variables were more significant for the definition of each of the categories.Results:The discriminative variables at 60°/s in the PRO category were: extension peak torque, flexion total work, extension average power and agonist/antagonist ratio; and for the U17s were: extension total work, flexion peak torque and flexion average power. At 120°/s for the PRO category the discriminant variables were: flexion peak torque and extension average power; for the U17s they were: extension total work and flexion average power. Finally at 300°/s, the variables found in the PRO and U17 categories respectively were: extension average power and extension total work.Conclusion:Isokinetic variables for flexion and extension knee muscles were able to significantly discriminate between PRO and U17 soccer players.

  10. Isokinetic muscle strength and readiness to return to sport following anterior cruciate ligament reconstruction: is there an association? A systematic review and a protocol recommendation.

    Science.gov (United States)

    Undheim, Marit Baste; Cosgrave, Ciaran; King, Enda; Strike, Siobhán; Marshall, Brendan; Falvey, Éanna; Franklyn-Miller, Andrew

    2015-10-01

    Following anterior cruciate ligament reconstruction (ACLR), strength is a key variable in regaining full function of the knee. Isokinetic strength is commonly used as part of the return to sport (RTS) criteria. We systematically reviewed the isokinetic strength evaluation protocols that are currently being used following ACLR. A secondary aim was to suggest an isokinetic protocol that could meet RTS criteria. Articles were searched using ScienceDirect, PubMed and Sage Journals Online, combined with cross-checked reference lists of the publications. Protocol data and outcome measurements and RTS criteria were extracted from each article included in the review. 39 studies met the inclusion criteria and reported their isokinetic strength evaluation protocol following ACLR. The variables that were most commonly used were concentric/concentric mode of contraction (31 studies), angular velocity of 60°/s (29 studies), 3-5 repetitions (24 studies), range of motion of 0-90° (6 studies), and using gravity correction (9 studies). 8 studies reported strength limb symmetry index scores as part of their RTS criteria. There was no standardised isokinetic protocol following ACLR; isokinetic strength measures have not been validated as useful predictors of successful RTS. We propose a standard protocol to allow consistency of testing and accurate comparison of future research. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  11. Neural and morphological adaptations of vastus lateralis and vastus medialis muscles to isokinetic eccentric training

    Directory of Open Access Journals (Sweden)

    Rodrigo de Azevedo Franke

    2014-09-01

    Full Text Available Vastus lateralis (VL and vastus medialis (VM are frequently targeted in conditioning/rehabilitation programs due to their role in patellar stabilization during knee extension. This study assessed neural and muscular adaptations in these two muscles after an isokinetic eccentric training program. Twenty healthy men underwent a four-week control period followed by a 12-week period of isokinetic eccentric training. Ultrasound evaluations of VL and VM muscle thickness at rest and electromyographic evaluations during maximal isometric tests were used to assess the morphological and neural properties, respectively. No morphological and neural changes were found throughout the control period, whereas both muscles showed significant increases in thickness (VL = 6.9%; p .05 post-training. Isokinetic eccentric training produces neural and greater morphological adaptations in VM compared to VL, which shows that synergistic muscles respond differently to an eccentric isokinetic strength training program

  12. Effects of the bilateral isokinetic strengthening training on functional parameters, gait, and the quality of life in patients with stroke.

    Science.gov (United States)

    Büyükvural Şen, Sıdıka; Özbudak Demir, Sibel; Ekiz, Timur; Özgirgin, Neşe

    2015-01-01

    To evaluate the effects of the bilateral isokinetic strengthening training applied to knee and ankle muscles on balance, functional parameters, gait, and the quality of in stroke patients. Fifty patients (33 M, 17 F) with subacute-chronic stroke and 30 healthy subjects were included. Stroke patients were allocated into isokinetic and control groups. Conventional rehabilitation program was applied to all cases; additionally maximal concentric isokinetic strengthening training was applied to the knee-ankle muscles bilaterally to the isokinetic group 5 days a week for 3 weeks. Biodex System 3 Pro Multijoint System isokinetic dynamometer was used for isokinetic evaluation. The groups were assessed by Functional Independence Measure, Stroke Specific Quality of Life Scale, Timed 10-Meter Walk Test, Six-Minute Walk Test, Stair-Climbing Test, Timed up&go Test, Berg Balance Scale, and Rivermead Mobility Index. Compared with baseline, the isokinetic PT values of the knee and ankle on both sides significantly increased in all cases. PT change values were significantly higher in the isokinetic group than the control group (Pisokinetic group (Pisokinetic strengthening training in addition to conventional rehabilitation program after stroke seems to be effective on strengthening muscles on both sides, improving functional parameters, gait, balance and life quality.

  13. The isokinetic strength profile of elite soccer players according to playing position.

    Directory of Open Access Journals (Sweden)

    Robert Śliwowski

    Full Text Available The aim of this study was to compare isokinetic strength performance profiles in elite soccer players across different field positions. A total of 111 elite international players of Polish Ekstraklasa (the top division in Poland were examined during the 2010-2015 seasons. The players were classified into six positional roles: central defenders (CD, external defenders (ED, central midfielders (CM, external midfielders (EM, forwards (F, and goalkeepers (G. The concentric isokinetic strength (peak torque [PT] of quadriceps and hamstrings, H/Q ratios was calculated for the dominant leg and the non-dominant leg at angular velocity of 1.05 rad ·s-1, whereas to assess isokinetic muscle endurance, the total work [TW] at angular velocity of 4.19 rad ·s-1, was taken into consideration. The results showed that isokinetic strength performance varies significantly among players in different playing positions. The analysis of PT for quadriceps (PT-Q and hamstrings (PT-H generally showed that the goalkeepers and central midfielders had lower strength levels compared to other playing positions. In the case of PT-H and hamstring/quadricep (H/Q peak torque ratios, statistically significant differences were also noted for the legs, where mean values noted for the dominant leg were higher than for the non-dominant leg. For TW for quadriceps (TW-Q and hamstrings (TW-H, statistically significant differences were noted only between playing positions. TW-Q values for goalkeepers were lower than for central defenders and external midfielders. TW-H values for goalkeepers were lower than for central midfielders, central defenders and external midfielders. This study showed that specific functional activity of players in individual positions on the field influences the varied profile of isokinetic strength performance.

  14. Enthalpy-entropy compensation and the isokinetic temperature in ...

    Indian Academy of Sciences (India)

    Enthalpy-entropy compensation supposes that differences in activation enthalpy delta-H-++ for different reactions (or, typically inbiochemistry, the same reaction catalysed by enzymes obtained from different species) may be compensated for bydifferences in activation entropy delta-S-++. At the isokinetic temperature the ...

  15. Isokinetic trunk muscle performance in pre-teens and teens with and without back pain.

    Science.gov (United States)

    Bernard, J-C; Boudokhane, S; Pujol, A; Chaléat-Valayer, E; Le Blay, G; Deceuninck, J

    2014-02-01

    To assess with an isokinetic dynamometer the force and endurance of the spinal flexor and extensor muscles in pre-teens or teens aged 11 to 13 and 14 to 16 years with and without low back pain (LBP). The control group and the LBP group were homogeneous in terms of age, weight, height and Body Mass Index (BMI). Assessment was carried out with the isokinetic dynamometer Cybex Norm®. The spinal flexors and extensors were explored concentrically at speeds of 60°, 90° and 120°/sec. The parameters chosen were: maximal moment of force (MMF), mean power (MP), total work (TW), F/E ratios (between the flexors and the extensors for the aforesaid parameters). In the LBP groups, clinical information (pain, extensibility of the spinal and sub-pelvic muscles, sports practice) and sagittal radiological data were all measured. While no significant difference in isokinetic performance was found between asymptomatic and LBP children in the 11-to-13-year-old group, the isokinetic performances of the LBP children were influenced positively by BMI value, number of hours of physical activity and radiologic value of the lumbar lordosis. As regards these pre-teens, assessment with an isokinetic dynamometer does not highlight muscle characteristics that might explain LBP occurrence. As regards the 14-to-16-year-old group, muscle strength has been found to be correlated with age. LBP teens were showed to have weaker extensors and stronger flexors than the healthy teens. It is with regard to this age group that assessment with an isokinetic dynamometer clearly yields interesting results. Since we have yet to standardize our evaluation criteria (working speed, number of trials…), it is difficult to compare our results with those reported in the literature. This is a preliminary study involving a relatively low number of patients. That said, given the fact that numerous parameters are connected with the age and height of the subjects, assessment with an isokinetic dynamometer can be

  16. Interseason variability in isokinetic strength and poor correlation with Nordic hamstring eccentric strength in football players.

    Science.gov (United States)

    van Dyk, N; Witvrouw, E; Bahr, R

    2018-04-25

    In elite sport, the use of strength testing to establish muscle function and performance is common. Traditionally, isokinetic strength tests have been used, measuring torque during concentric and eccentric muscle action. A device that measures eccentric hamstring muscle strength while performing the Nordic hamstring exercise is now also frequently used. The study aimed to investigate the variability of isokinetic muscle strength over time, for example, between seasons, and the relationship between isokinetic testing and the new Nordic hamstring exercise device. All teams (n = 18) eligible to compete in the premier football league in Qatar underwent a comprehensive strength assessment during their periodic health evaluation at Aspetar Orthopaedic and Sports Medicine Hospital in Qatar. Isokinetic strength was investigated for measurement error, and correlated to Nordic hamstring exercise strength. Of the 529 players included, 288 players had repeated tests with 1/2 seasons between test occasions. Variability (measurement error) between test occasions was substantial, as demonstrated by the measurement error (approximately 25 Nm, 15%), whether separated by 1 or 2 seasons. Considering hamstring injuries, the same pattern was observed among injured (n = 60) and uninjured (n = 228) players. A poor correlation (r = .35) was observed between peak isokinetic hamstring eccentric torque and Nordic hamstring exercise peak force. The strength imbalance between limbs calculated for both test modes was not correlated (r = .037). There is substantial intraindividual variability in all isokinetic test measures, whether separated by 1 or 2 seasons, irrespective of injury. Also, eccentric hamstring strength and limb-to-limb imbalance were poorly correlated between the isokinetic and Nordic hamstring exercise tests. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Isokinetic sampler; Amostrador isocinetico

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luis Cesar C. de; Santos, Antonio Carlos dos [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil); Barrio, Lara B.A. del [AZ Armaturen do Brasil Ltda., Itatiba, SP (Brazil); Silva, Claudio B. da C. e; Silva, Ricardo R. da [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2005-07-01

    The Center of Research Leopoldo A. Miguez de Melo - CENPES - in association with AZ Armaturen Company do Brasil and TRANSPETRO developed and tested an Isokinetic sampler. This work presents the sampling principles and the results and performance of the tests realized in the 'Sitio de Testes de Atalaia' and in one of the terminals of bunker transfer of TRANSPETRO - 'Terminal Aquaviario da Baia de Guanabara'. In the 'Sitio de Testes' the products used were oil and water with BSW from 5% to 97% and in the terminal were tested samplings of bunker with ranges viscosities between (MF 180 to 380). (author)

  18. Validity and reliability of isometric, isokinetic and isoinertial modalities for the assessment of quadriceps muscle strength in patients with total knee arthroplasty.

    Science.gov (United States)

    Lienhard, K; Lauermann, S P; Schneider, D; Item-Glatthorn, J F; Casartelli, N C; Maffiuletti, N A

    2013-12-01

    Reliability of isometric, isokinetic and isoinertial modalities for quadriceps strength evaluation, and the relation between quadriceps strength and physical function was investigated in 29 total knee arthroplasty (TKA) patients, with an average age of 63 years. Isometric maximal voluntary contraction torque, isokinetic peak torque, and isoinertial one-repetition maximum load of the involved and uninvolved quadriceps were evaluated as well as objective (walking parameters) and subjective physical function (WOMAC). Reliability was good and comparable for the isometric, isokinetic, and isoinertial strength outcomes on both sides (intraclass correlation coefficient range: 0.947-0.966; standard error of measurement range: 5.1-9.3%). Involved quadriceps strength was significantly correlated to walking speed (r range: 0.641-0.710), step length (r range: 0.685-0.820) and WOMAC function (r range: 0.575-0.663), independent from the modality (P strength was also significantly correlated to walking speed (r range: 0.413-0.539), step length (r range: 0.514-0.608) and WOMAC function (r range: 0.374-0.554) (P 0.05). In conclusion, isometric, isokinetic, and isoinertial modalities ensure valid and reliable assessment of quadriceps muscle strength in TKA patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Thoracic posture, shoulder muscle activation patterns and isokinetic ...

    African Journals Online (AJOL)

    Background. Shoulder injuries are the most severe injuries in rugby union players, accounting for almost 20% of injuries related to the sport and resulting in lost playing hours. Objective. To profile the thoracic posture, scapular muscle activation patterns and rotator cuff muscle isokinetic strength of semi-professional

  20. THE EFFECTS OF ISOKINETIC KNEE STRENGTH ON THE PROMPTNESS OF SOCCER PLAYERS

    OpenAIRE

    Ali Kerim Yilmaz; Menderes Kabadayi; Muhammet Hakan Mayda; Murşit Ceyhun Birinci; Mustafa Özdal

    2017-01-01

    The purpose of this study is to examine the effects of isokinetic knee strength on promptness. 15 soccer players with an average age of 22,80±2,14 years and 15 controls with an average age of 21,60±1,40 years participated in the study. Body composition, isokinetic knee strength measurement at angular speeds of 60o, 180o, 240o and 10 m sprint test were conducted respectively in the study. General warm-up procedure was carried out on the groups before measurements. In statistical analyses, Shap...

  1. Relative differences in strength and power from slow to fast isokinetic velocities may reflect dynapenia.

    Science.gov (United States)

    Jenkins, Nathaniel D M; Housh, Terry J; Palmer, Ty B; Cochrane, Kristen C; Bergstrom, Haley C; Johnson, Glen O; Schmidt, Richard J; Cramer, Joel T

    2015-07-01

    We compared absolute and normalized values for peak torque (PT), mean power (MP), rate of velocity development, and electromyography (EMG) amplitude during maximal isometric and concentric isokinetic leg extension muscle actions, as well as the %decrease in PT and %increase in MP from 1.05 to 3.14 rad·s(-1) in younger versus older men. Measurements were performed twice for reliability. Isokinetic measurements were normalized to the isometric muscle actions. Absolute isometric PT, isokinetic PT and MP, and EMG amplitudes at 1.05 and 3.14 rad·s(-1) were greater in the younger men, although normalizing to isometric PT eliminated the age differences. The older men exhibited greater %decrease in PT (37.2% vs. 31.3%) and lower %increase in MP (87.6% vs. 126.4%) regardless of normalization. Normalization eliminated absolute differences in isokinetic strength and power, but the relative differences from slow to fast velocities may reflect dynapenia characterized by age-related decreases in fast-twitch fiber function. © 2014 Wiley Periodicals, Inc.

  2. RELATIONSHIP BETWEEN ISOKINETIC KNEE STRENGTH AND JUMP CHARACTERISTICS FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION.

    Science.gov (United States)

    Laudner, Kevin; Evans, Daniel; Wong, Regan; Allen, Aaron; Kirsch, Tom; Long, Brian; Meister, Keith

    2015-06-01

    Clinicians are often challenged when making return-to-play decisions following anterior cruciate ligament reconstruction (ACL-R). Isokinetic strength and jump performance testing are common tools used to make this decision. Unfortunately, vertical jump performance standards have not been clearly established and many clinicians do not have access to isokinetic testing equipment. To establish normative jump and strength characteristics in ACL-R patients cleared by an orthopedic physician to return-to-play and to determine if relationships exist between knee isokinetic strength measurements and jump characteristics described using an electronic jump map system. Descriptive laboratory study. Thirty-three ACL-R patients who had been cleared to return to athletic competition participated in this study. Twenty-six of these ACL-R participants were also matched to 26 asymptomatic athletes based on sex, limb, height, and mass to determine isokinetic strength and jump characteristic differences between groups. Jump tests consisted of single leg vertical, double leg vertical, and a 4-jump single leg vertical jump assessed using an electronic jump mat system. Independent t-tests were used to determine differences between groups and multiple regression analyses were used to identify any relationships between jump performance and knee strength (pjump capabilities and some bilateral knee strength deficiencies compared to the matched control group. The ACL-R group also showed several moderate-to-strong positive relationships for both knee extension and flexion strength with several jump performance characteristics, such as single and double leg vertical jump height. The current results indicate that ACL-R patients present with several knee strength and vertical jump differences compared to a matched control group at the time of return-to-play. Also, ACL-R patient's performance on an electronic jump mat system is strongly related to isokinetic knee strength measures. 2b.

  3. Reliability of Concentric, Eccentric and Isometric Knee Extension and Flexion when using the REV9000 Isokinetic Dynamometer

    DEFF Research Database (Denmark)

    de Carvalho Froufe Andrade, Alberto César Pereira; Caserotti, Paolo; de Carvalho, Carlos Manuel Pereira

    2013-01-01

    The aim of this study was to assess the reliability of isokinetic and ISO knee extensor and flexor muscle strength when using the REV9000 (Technogym) isokinetic dynamometer. Moreover, the reliability of several strength imbalance indices and bilateral ratios were also examined. Twenty-four physic...

  4. Assessment of isokinetic knee strength in elite young female basketball players: correlation with vertical jump.

    Science.gov (United States)

    Rouis, M; Coudrat, L; Jaafar, H; Filliard, J-R; Vandewalle, H; Barthelemy, Y; Driss, T

    2015-12-01

    To explore the isokinetic concentric strength of the knee muscle groups, and the relationship between the isokinetic knee extensors strength and the vertical jump performance in young elite female basketball players. Eighteen elite female basketball players performed a countermovement jump, and an isokinetic knee test using a Biodex dynamometer. The maximal isokinetic peak torque of the knee extensor and flexor muscles was recorded at four angular velocities (90°/s, 180°/s, 240°/s and 300°/s) for the dominant and non-dominant legs. The conventional hamstring/quadriceps ratio (H/Q) was assessed at each angular velocity for both legs. There was no significant difference between dominant and non-dominant leg whatever the angular velocity (all P>0.05). However, the H/Q ratio enhanced as the velocity increased from 180°/s to 300°/s (Pvertical jump height. The highest one was found for the knee extensors peak torque at a velocity of 240°/s (r=0.88, Pvertical jump height. Interestingly, the H/Q ratio of the young elite female basketball players in the present study was unusual as it was close to that generally observed in regular sportsmen.

  5. Effects of the bilateral isokinetic strengthening training on functional parameters, gait, and the quality of life in patients with stroke

    OpenAIRE

    Büyükvural Şen, Sıdıka; Özbudak Demir, Sibel; Ekiz, Timur; Özgirgin, Neşe

    2015-01-01

    Objective: To evaluate the effects of the bilateral isokinetic strengthening training applied to knee and ankle muscles on balance, functional parameters, gait, and the quality of in stroke patients. Methods: Fifty patients (33 M, 17 F) with subacute-chronic stroke and 30 healthy subjects were included. Stroke patients were allocated into isokinetic and control groups. Conventional rehabilitation program was applied to all cases; additionally maximal concentric isokinetic strengthening traini...

  6. Influence of visual feedback on knee extensor isokinetic concentric ...

    African Journals Online (AJOL)

    Isokinetic normative data can be invaluable in identifying an individual's strengths and weaknesses, and thus lead to a more effective use of the individual's time to minimise or overcome his weaknesses while maintaining or improving existing strength. However, visual feedback (VF) may significantly affect the result of ...

  7. Combined effects of myofeedback and isokinetic training on hand ...

    African Journals Online (AJOL)

    Khaled A. Olama

    2012-04-25

    Apr 25, 2012 ... Subjects and methods: Thirty spastic hemiplegic children from both sexes ranging in age from ... physical therapy program with isokinetic training for the triceps brachii muscle for 60 min, in ... The Egyptian Journal of Medical Human Genetics ... than a third of all cases of CP, and the resulting impairments.

  8. Isokinetic hamstring and quadriceps muscle strength profiles of elite ...

    African Journals Online (AJOL)

    Football players are at risk of lower limb injuries, specifically hamstring muscle strains and ACL injuries due to muscle imbalances. This was a descriptive study assessing the isokinetic hamstring and quadriceps muscle strength and endurance in 28 elite, male, South African football players. Muscle strength was tested at 60 ...

  9. Isometric and isokinetic muscle strength in patients with fibrositis syndrome. New characteristics for a difficult definable category of patients

    DEFF Research Database (Denmark)

    Jacobsen, Søren; Danneskiold-Samsøe, B

    1987-01-01

    A common complaint among patients with fibrositis syndrome is exhaustion and fatique. It was therefore felt desirable to evaluate the muscle strength of these patients compared with normal subjects. Maximum isometric and isokinetic strength of knee extension was measured in 15 patients and 15...... healthy matched subjects, using an isokinetic dynamometer (Cybex II). Maximum isometric strength at various knee extension angles (90 degrees, 60 degrees and 30 degrees degrees) was significantly (p less than 0.001) lower in the fibrositis group than in controls, a reduction of approximately 58......-66%. Maximum isokinetic strength at various knee extension velocities (30-240 degrees per second) was also significantly (p less than 0.01) lower in the fibrositis group than in controls, the reduction being approximately 41-51%. In conclusion, isometric and isokinetic muscle strength is found to be lower...

  10. Isokinetic analysis of ankle and ground reaction forces in runners and triathletes

    Directory of Open Access Journals (Sweden)

    Natália Mariana Silva Luna

    2012-09-01

    Full Text Available OBJECTIVE: To analyze and compare the vertical component of ground reaction forces and isokinetic muscle parameters for plantar flexion and dorsiflexion of the ankle between long-distance runners, triathletes, and nonathletes. METHODS: Seventy-five males with a mean age of 30.26 (±6.5 years were divided into three groups: a triathlete group (n=26, a long-distance runner group (n = 23, and a non-athlete control group. The kinetic parameters were measured during running using a force platform, and the isokinetic parameters were measured using an isokinetic dynamometer. RESULTS: The non-athlete control group and the triathlete group exhibited smaller vertical forces, a greater ground contact time, and a greater application of force during maximum vertical acceleration than the long-distance runner group. The total work (180º/s was greater in eccentric dorsiflexion and concentric plantar flexion for the non-athlete control group and the triathlete group than the long-distance runner group. The peak torque (60º/s was greater in eccentric plantar flexion and concentric dorsiflexion for the control group than the athlete groups. CONCLUSIONS: The athlete groups exhibited less muscle strength and resistance than the control group, and the triathletes exhibited less impact and better endurance performance than the runners.

  11. Isokinetic knee strength qualities as predictors of jumping performance in high-level volleyball athletes: multiple regression approach.

    Science.gov (United States)

    Sattler, Tine; Sekulic, Damir; Spasic, Miodrag; Osmankac, Nedzad; Vicente João, Paulo; Dervisevic, Edvin; Hadzic, Vedran

    2016-01-01

    Previous investigations noted potential importance of isokinetic strength in rapid muscular performances, such as jumping. This study aimed to identify the influence of isokinetic-knee-strength on specific jumping performance in volleyball. The secondary aim of the study was to evaluate reliability and validity of the two volleyball-specific jumping tests. The sample comprised 67 female (21.96±3.79 years; 68.26±8.52 kg; 174.43±6.85 cm) and 99 male (23.62±5.27 years; 84.83±10.37 kg; 189.01±7.21 cm) high- volleyball players who competed in 1st and 2nd National Division. Subjects were randomly divided into validation (N.=55 and 33 for males and females, respectively) and cross-validation subsamples (N.=54 and 34 for males and females, respectively). Set of predictors included isokinetic tests, to evaluate the eccentric and concentric strength capacities of the knee extensors, and flexors for dominant and non-dominant leg. The main outcome measure for the isokinetic testing was peak torque (PT) which was later normalized for body mass and expressed as PT/Kg. Block-jump and spike-jump performances were measured over three trials, and observed as criteria. Forward stepwise multiple regressions were calculated for validation subsamples and then cross-validated. Cross validation included correlations between and t-test differences between observed and predicted scores; and Bland Altman graphics. Jumping tests were found to be reliable (spike jump: ICC of 0.79 and 0.86; block-jump: ICC of 0.86 and 0.90; for males and females, respectively), and their validity was confirmed by significant t-test differences between 1st vs. 2nd division players. Isokinetic variables were found to be significant predictors of jumping performance in females, but not among males. In females, the isokinetic-knee measures were shown to be stronger and more valid predictors of the block-jump (42% and 64% of the explained variance for validation and cross-validation subsample, respectively

  12. The Effects of Isokinetic Strength Training on Strength at Different Angular Velocities: a Pilot Study

    Directory of Open Access Journals (Sweden)

    Tuğba Kocahan

    2017-09-01

    Conclusion: It was shown that angular velocity is important in isokinetic training, and that training at high angular velocities provides strength increases at lower angular velocities, but would not increase strength at angular velocities above the training level. For this reason, it is thought that in the preparation of an isokinetic strength training protocol, angular velocities need to be taken into account. For any athlete, the force at the angular velocity required in her/his sports branch needs to be considered.

  13. [Progress in isokinetic technology in testing and training for assessment of muscle function].

    Science.gov (United States)

    Huang, Ting-Ting; Fan, Li-Hua; Gao, Dong; Xia, Qing; Zhang, Min

    2013-02-01

    Isokinetic technology in testing and training is the most advanced practical technique in the evaluation of muscle function. This method is a continuous dynamic test in the full range of the joint motion which has strong pertinence at the aspect of assessing muscle strength, and is an objective and quantitative method for reflecting each point's muscle strength in the range of the joint motion. This article reviews the key concepts, brief history of development and influencing factors of isokinetic technology in testing and training, introduces the progress in the field of rehabilitation medicine and sport science, etc., and discusses the future exploration in forensic science.

  14. Analysis of the association between isokinetic knee strength with offensive and defensive jumping capacity in high-level female volleyball athletes.

    Science.gov (United States)

    Sattler, Tine; Sekulic, Damir; Esco, Michael R; Mahmutovic, Ifet; Hadzic, Vedran

    2015-09-01

    Isokinetic-knee-strength was hypothesized to be an important factor related to jumping performance. However, studies examining this relation among elite female athletes and sport-specific jumps are lacking. This investigation determined the influence of isokinetic-knee flexor/extensor strength measures on spike-jump (offensive) and block-jump (defensive) performance among high-level female volleyball players. Cross-sectional laboratory study. Eighty-two female volleyball athletes (age = 21.3 ± 3.8 years, height = 175.4 ± 6.76 cm, and weight = 68.29 ± 8.53 kg) volunteered to participate in this study. The studied variables included spike-jump and block-jump performance and a set of isokinetic tests to evaluate the eccentric and concentric strength capacities of the knee extensors (quadriceps - Q), and flexors (hamstring - H) for both legs. Both jumping tests showed high intra-session reliability (ICC of 0.87 and 0.95 for spike-jump and block-jump, respectively). The athletes were clustered into three achievement-groups based on their spike-jump and block-jump performances. For the block-jump, ANOVA identified significant differences between achievement-groups for all isokinetic variables except the Right-Q-Eccentric-Strength. When observed for spike-jump, achievement-groups differed significantly in all tests but Right-H-Concentric-Strength. Discriminant canonical analysis showed that the isokinetic-strength variables were more associated with block-jump then spike-jump-performance. The eccentric isokinetic measures were relatively less important determinants of block-jump than for the spike-jump performance. Data support the hypothesis of the importance of isokinetic strength measures for the expression of rapid muscular performance in volleyball. The results point to the necessity of the differential approach in sport training for defensive and offensive duties. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  15. Results and Conclusions from the NASA Isokinetic Total Water Content Probe 2009 IRT Test

    Science.gov (United States)

    Reehorst, Andrew; Brinker, David

    2010-01-01

    The NASA Glenn Research Center has developed and tested a Total Water Content Isokinetic Sampling Probe. Since, by its nature, it is not sensitive to cloud water particle phase nor size, it is particularly attractive to support super-cooled large droplet and high ice water content aircraft icing studies. The instrument comprises the Sampling Probe, Sample Flow Control, and Water Vapor Measurement subsystems. Results and conclusions are presented from probe tests in the NASA Glenn Icing Research Tunnel (IRT) during January and February 2009. The use of reference probe heat and the control of air pressure in the water vapor measurement subsystem are discussed. Several run-time error sources were found to produce identifiable signatures that are presented and discussed. Some of the differences between measured Isokinetic Total Water Content Probe and IRT calibration seems to be caused by tunnel humidification and moisture/ice crystal blow around. Droplet size, airspeed, and liquid water content effects also appear to be present in the IRT calibration. Based upon test results, the authors provide recommendations for future Isokinetic Total Water Content Probe development.

  16. Efficacy of kinesio taping on isokinetic quadriceps torque in knee osteoarthritis: a double blinded randomized controlled study.

    Science.gov (United States)

    Anandkumar, Sudarshan; Sudarshan, Shobhalakshmi; Nagpal, Pratima

    2014-08-01

    Double blind pre-test post-test control group design. To compare the isokinetic quadriceps torque, standardized stair-climbing task (SSCT) and pain during SSCT between subjects diagnosed with knee osteoarthritis pre and post kinesio tape (KT) application with and without tension. Strength of the quadriceps and torque producing capability is frequently found to be compromised in knee osteoarthritis. The efficacy of KT in improving isokinetic quadriceps torque in knee osteoarthritis is unknown, forming the basis for this study. Forty subjects were randomly allocated to either the experimental (therapeutic KT with tension) or control group (sham KT without tension) with the allocation being concealed. Pre and post test measurements of isokinetic quadriceps torque, SSCT and pain during SSCT were carried out by a blinded assessor. A large effect size with significant improvements in the peak quadriceps torque (concentric and eccentric at angular velocities of 90° per second and 120° per second), SSCT and pain were obtained in the experimental group when compared to the control group. Application of therapeutic KT is effective in improving isokinetic quadriceps torque, SSCT and reducing pain in knee osteoarthritis.

  17. Reliability of a device for the knee and ankle isometric and isokinetic strength testing in older adults.

    Science.gov (United States)

    Bergamin, Marco; Gobbo, Stefano; Bullo, Valentina; Vendramin, Barbara; Duregon, Federica; Frizziero, Antonio; Di Blasio, Andrea; Cugusi, Lucia; Zaccaria, Marco; Ermolao, Andrea

    2017-01-01

    Lower extremity muscle mass, strength, power, and physical performance are critical determinants of independent functioning in later life. Isokinetic dynamometers are becoming very common in assessing different features of muscle strength, in both research and clinical practice; however, reliability studies are still needed to support the extended use of those devices. The purpose of this study is to assess the test-retest reliability of knee and ankle isokinetic and isometric strength testing protocols in a sample of older healthy subjects, using a new and untested isokinetic multi-joint evaluation system. Sixteen male and fourteen female older adults (mean age 65.2 ± 4.6 years) were assessed in two testing sessions. Each participant performed a randomized testing procedure that includes different isometric and isokinetic tests for knee and ankle joints. All participants concluded the trial safety and no subject reported any discomfort throughout the overall assessment. Coefficients of correlation between measures were calculated showing moderate to strong effects among all test-retest assessments and paired-sample t test showed only one significant difference (pisometric strength provided reliable test-retest measures in healthy older adults. Ib.

  18. Absolute and relative reliability of isokinetic and isometric trunk strength testing using the IsoMed-2000 dynamometer.

    Science.gov (United States)

    Roth, Ralf; Donath, Lars; Kurz, Eduard; Zahner, Lukas; Faude, Oliver

    2017-03-01

    The present study aimed to assess the between day reliability of isokinetic and isometric peak torque (PT) during trunk measurement on an isokinetic device (IsoMed 2000). Test-retest-protocol on five separate days. Fifteen healthy sport students (8 female and 7 male) aged 21 to 26. PT was assessed in isometric back extension and flexion as well as right and left rotation. Isokinetic strength was captured at a speed of 60°/s and 150°/s for all tasks. For none of the assessed parameters a meaningful variation in PT during test days was observed. Relative reliability (ICC = 0.85-0.96) was excellent for all tasks. Estimates of absolute reliability as Coefficient of Variation (CoV) and Standard Error of Measurement (SEM in Nm/kg lean body mass) remained stable for isometric (6.9% strength measurement in flexion and extension or trunk rotation in either isometric or isokinetic condition is highly reliable. Therefore, it seems possible to elucidate changes which are smaller than 10% due to intervention programs when a preceding familiarization condition was applied. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. The effect of isokinetic and proprioception training on strength, movement and gait parameters after acute supination injury of the ankle ligaments

    Directory of Open Access Journals (Sweden)

    C. Mucha

    2009-01-01

    Full Text Available The effects of a three-week isokinetic training compared to typical proprio -ceptive training on parameters of strength, movement and gait function after acute ankle ligament sprain were investigated. Thirty-nine patients were randomly allocated to two comparison groups. In group 1 (n=20a proprioceptive training and in group 2 (n=19 an isokinetic strength training (Cybex 6000® were administered. Thepatients of both groups underwent training five times a week for three weeks. Before and at the end of the treatmentcourse, in both groups isokinetic strength was tested, the range of motion in the ankle joint was recorded and gait wasanalyzed (multicomponent strength measurement platform, Henschel-System®. The maximum isokinetic torque(60°/s [Nm] and the contact time (monopedal support time of the injured leg during gait cycle were the basis for evaluation.The data obtained show that in group 2 a significantly greater increase of the maximum isokinetic torque wasattained in almost all range of motion of the ankle joint in the course of treatment. A t the same time, in group 2 theshortening of the contact time in the stance phase of the injured leg could be compensated. The active range of motionin the ankle joint was less at the end of treatment in group 2 than in group 1. The isokinetic training obviously did notonly lead to better strength regeneration, but also to a functionally more stable ankle joint with a rhythmically moreevenly balanced stance phase of the gait cycle.  These results suggest that the used isokinetic training had positive effects on functional stability after acute ankle sprain.

  20. Posture and isokinetic shoulder strength in female water polo players

    African Journals Online (AJOL)

    Background: Being overhead athletes, water polo players can present with muscular imbalances of the shoulder, between the internal rotators (IR) and external rotators (ER), leading to changes in posture and an increased risk of injury. Objectives: To assess posture and isokinetic shoulder strength of female club-level ...

  1. Dynamics of muscle strength improvement during isokinetic rehabilitation of athletes with ACL rupture and chondromalacia patellae.

    Science.gov (United States)

    Desnica Bakrac, N

    2003-03-01

    To assess quantitatively dynamics and extent of the increase in muscle strength during isokinetic rehabilitation. daily measurements of muscle strength; detailed testing at the beginning and at the end of rehabilitation. Cybex Rehabilitation Center, Zagreb. 44 athletes (31 m, 13 F, age 16-35), 3 injury-defined groups: athletes with ACL rupture (non-reconstructed and reconstructed) and chondromalacia patellae. all subjects underwent isokinetic rehabilitation on Cybex Orthotron KT2 device, using individually designed protocols (extension and flexion exercises, concentric muscle contractions, 15 treatments). monitoring of daily progress on rehabilitation device and detailed testing on diagnostic device. All patients showed considerable improvement. Muscle strength improved on average 141% (SD=110) in ACL-reconstructed group, 144% (SD=130) for chondromalacia patellae group and 150% (SD=74) for ACL-non-reconstructed group, comparing to initial strength. Dynamic status tested on Cybex Otrhotron diagnostic device prior and after rehabilitation strongly correlated with final progress monitored on the rehabilitation device. Isokinetic rehabilitation is a quick and effective method in treating knee injuries in athletes. Both types of objective criteria have shown significant increase in muscle strength. The improvement of muscle strength was on the average 149% (SD=101), which is about 10% daily for 15 treatments. The greatest progress, 19% per day, occurred during first five days. The athletes were able to resume their sport activities as follows: patients from chondromalacia patellae group, and most of them from the non-reconstructed ACL group were back in competition within a month, while 75% from the ACL reconstructed group came back within 3 months, and the rest of them within 5 months.

  2. Isometric and isokinetic muscle strength in the upper extremity can be reliably measured in persons with chronic stroke.

    Science.gov (United States)

    Ekstrand, Elisabeth; Lexell, Jan; Brogårdh, Christina

    2015-09-01

    To evaluate the test-retest reliability of isometric and isokinetic muscle strength measurements in the upper extremity after stroke. A test-retest design. Forty-five persons with mild to moderate paresis in the upper extremity > 6 months post-stroke. Isometric arm strength (shoulder abduction, elbow flexion), isokinetic arm strength (elbow extension/flexion) and isometric grip strength were measured with electronic dynamometers. Reliability was evaluated with intra-class correlation coefficients (ICC), changes in the mean, standard error of measurements (SEM) and smallest real differences (SRD). Reliability was high (ICCs: 0.92-0.97). The absolute and relative (%) SEM ranged from 2.7 Nm (5.6%) to 3.0 Nm (9.4%) for isometric arm strength, 2.6 Nm (7.4%) to 2.9 Nm (12.6%) for isokinetic arm strength, and 22.3 N (7.6%) to 26.4 N (9.2%) for grip strength. The absolute and relative (%) SRD ranged from 7.5 Nm (15.5%) to 8.4 Nm (26.1%) for isometric arm strength, 7.1 Nm (20.6%) to 8.0 Nm (34.8%) for isokinetic arm strength, and 61.8 N (21.0%) to 73.3 N (25.6%) for grip strength. Muscle strength in the upper extremity can be reliably measured in persons with chronic stroke. Isometric measurements yield smaller measurement errors than isokinetic measurements and might be preferred, but the choice depends on the research question.

  3. Identification of cardiac repercussions after intense and prolonged concentric isokinetic exercise in young sedentary people.

    Science.gov (United States)

    Le Goff, Caroline; Kaux, Jean-François; Couffignal, Vincent; Coubard, Romain; Mélon, Pierre; Cavalier, Etienne; Croisier, Jean-Louis

    2015-09-01

    Cardiopathies are the world's leading cause of mortality and morbidity. Although rare, cardiovascular accidents can occur during intense and infrequent sporting activity, particularly among those who are unaware of their heart condition. The development of cardiospecific biochemical markers has led to a reconsideration of the role of biology in the diagnosis of cardiovascular illnesses. The aim of this study therefore was, through the use of cardiac biomarker assays, to highlight the impact of sustained physical effort in the form of intense and prolonged concentric isokinetic exercise and to research potential cardiovascular risks. Eighteen subjects participated in a maximal concentric isokinetic exercise involving 30 knee flexion-extensions for each leg. Five blood tests were taken to study the kinetics of the cardiac biomarkers. Haemodynamic parameters were measured continuously using a Portapres, and respiratory parameters were measured using a Sensormedics Vmax 29C. The results showed significant increases in the creatine kinase, myoglobin, homocysteine and haemoglobin cardiac markers. Evolutionary trends were also observed for the following biomarkers: NT-proBNP, myeloperoxydase and C-reactive protein. All the physiological parameters measured presented statistically significant changes. Isokinetic effort leads to the release of cardiac markers in the blood, but these do not exceed the reference values in healthy subjects. Maximal concentric isokinetic exercise does not, therefore, lead to an increased risk of cardiovascular pathologies. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  4. Association with isokinetic ankle strength measurements and normal clinical muscle testing in sciatica patients.

    Science.gov (United States)

    Ustun, N; Erol, O; Ozcakar, L; Ceceli, E; Ciner, O Akar; Yorgancioglu, Z R

    2013-01-01

    Sensitive muscle strength tests are needed to measure muscle strength in the diagnosis and management of sciatica patients. The aim of this study was to assess the isokinetic muscle strength in sciatica patients' and control subjects' ankles that exhibited normal ankle muscle strength when measured clinically. Forty-six patients with L5 and/or S1 nerve compression, and whose age, sex, weight, and height matched 36 healthy volunteers, were recruited to the study. Heel-walking, toe-walking, and manual muscle testing were used to perform ankle dorsiflexion and plantar flexion strengths in clinical examination. Patients with normal ankle dorsiflexion and plantar flexion strengths assessed by manual muscle testing and heel-and toe-walking tests were included in the study. Bilateral isokinetic (concentric/concentric) ankle plantar-flexion-dorsiflexion measurements of the patients and controls were performed within the protocol of 30°/sec (5 repetitions). Peak torque and peak torque/body weight were obtained for each ankle motion of the involved limb at 30°/s speed. L5 and/or S1 nerve compression was evident in 46 patients (76 injured limbs). Mean disease duration was two years. The plantar flexion muscle strength of the patients was found to be lower than that of the controls (p=0.036). The dorsiflexion muscle strength of the patients was found to be the same as that of the controls (p=0.211). Isokinetic testing is superior to clinical muscle testing when evaluating ankle plantar flexion torque in sciatica patients. Therefore, isokinetic muscle testing may be helpful when deciding whether to place a patient into a focused rehabilitation program.

  5. A Comparison of Isokinetic Knee Strength and Power Output Ratios Between Female Basketball and Volleyball Players

    Directory of Open Access Journals (Sweden)

    Kabaciński Jarosław

    2017-09-01

    Full Text Available Purpose. Tests such as the counter movement jump (CMJ and squat jump (SJ allow for determining the ratio of maximal power output generated during SJ to CMJ (S/C. The isokinetic peak torque ratio of the hamstrings contracting eccentrically to the quadriceps contracting concentrically (H/Q is defined as functional H/Q. The purpose of this study was to compare the S/C and functional H/Q between female basketball and volleyball players. Methods. The total of 14 female basketball players (age, 19.8 ± 1.4 years and 12 female volleyball players (age, 22.3 ± 4.2 years participated in the study. A piezoelectric force platform was used for the CMJ and SJ. Moreover, isokinetic tests of the hamstrings and quadriceps muscle torque during eccentric and concentric contraction were performed. Results. The results of the S/C and functional H/Q at 90 deg · s-1/60 deg · s-1 velocities were higher in basketball players (87.3 ± 9.1% and 91.4 ± 9.3%, respectively than in volleyball players (83.1 ± 9.8% and 83.6 ± 16.5%, respectively. No significant differences in S/C or functional H/Q values between the two groups were found (p > 0.05. Conclusions. Decreasing the S/C may result from an improvement in the power output during CMJ and a better utilization of the stretch-shortening cycle effect. Balancing the functional H/Q through increasing the eccentric hamstrings strength can provide dynamic knee joint stabilization.

  6. The reliability of data produced by isokinetic dynamometry (IKD) of ...

    African Journals Online (AJOL)

    To investigate the feasibility of using isolated knee performance to measure the f-v profile of human muscle in vivo, we were using isokinetic dynamometry (IKD) technique that span the entire f-v profile of skeletal muscle. With institutional ethics approval, eleven healthy males (mean ± SD: age, 24.9 ± 3.1 years; body mass, ...

  7. Single-Leg Hop Test Performance and Isokinetic Knee Strength After Anterior Cruciate Ligament Reconstruction in Athletes.

    Science.gov (United States)

    Sueyoshi, Ted; Nakahata, Akihiro; Emoto, Gen; Yuasa, Tomoki

    2017-11-01

    Isokinetic strength and hop tests are commonly used to assess athletes' readiness to return to sport after knee surgery. The purpose of this study was to investigate the results of single-leg hop and isokinetic knee strength testing in athletes who underwent anterior cruciate ligament reconstruction (ACLR) upon returning to sport participation as well as to study the correlation between these 2 test batteries. The secondary purpose was to compare the test results by graft type (patellar tendon or hamstring). It was hypothesized that there would be no statistically significant limb difference in either isokinetic knee strength or single-leg hop tests, that there would be a moderate to strong correlation between the 2 test batteries, and that there would be no significant difference between graft types. Cross-sectional study; Level of evidence, 3. Twenty-nine high school and collegiate athletes who underwent ACLR participated in this study. At the time of return to full sport participation, a series of hop tests and knee extension/flexion isokinetic strength measurements were conducted. The results were analyzed using analysis of variance and Pearson correlation ( r ). The timed 6-m hop test was the only hop test that showed a significant difference between the involved and uninvolved limbs (2.3 and 2.2 seconds, respectively; P = .02). A significant difference between limbs in knee strength was found for flexion peak torque/body weight at 180 deg/s ( P = .03), flexion total work/body weight at 180 deg/s ( P = .04), and flexion peak torque/body weight at 300 deg/s ( P = .03). The strongest correlation between the hop tests and knee strength was found between the total distance of the hop tests and flexion total work/body weight at 300 deg/s ( r = 0.69) and between the timed 6-m hop test and flexion peak torque/body weight at 300 deg/s ( r = -0.54). There was no statistically significant difference in hop test performance or isokinetic knee strength between graft types

  8. Isokinetic muscle performance of the hip and ankle muscles in women with fibromyalgia.

    Science.gov (United States)

    Yetişgin, Alparslan; Tiftik, Tülay; Kara, Murat; Karabay, İlkay; Akkuş, Selami; Ersöz, Murat

    2016-06-01

    To compare isokinetic muscle performances of a proximal (hip) and a distal (ankle) muscle of fibromyalgia syndrome (FMS) patients with those of age- and body mass index (BMI)-matched healthy subjects. Thirty female patients with FMS (mean age: 41.5 ± 6.7 years [range, 27-54]) and 30 age- (mean age: 40.6 ± 6.0 years [range, 27-54]) and BMI-matched female healthy controls were consecutively enrolled. Demographic and clinical characteristics of the subjects were recorded. Isokinetic measurements of hip and ankle flexion and extension at angular velocities of 60°/s and 180°/s, peak torques, flexor-extensor torque ratios, muscle fatigue resistance values and average power were obtained. Mean disease duration of FMS patients was 2.4 ± 1.9 years. Mean weight, height and BMI values were 70.4 ± 12.5 kg, 159.5 ± 6.0 cm and 27.7 ± 4.7 kg/m² (FMS patients) and 69.3 ± 10.1 kg, 161.7 ± 6.2 cm and 26.6 ± 4.3 kg/m² (control subjects), respectively (all P > 0.05). All isokinetic values were statistically decreased in the FMS group when compared with the control group, except for the peak torques at angular velocity of 180°/s on flexion of the hip and extension of the ankle and the total work and average power on extension of the ankle. We did not find any correlation between isokinetic values and disease related parameters of FMS patients. In the light of our results, we may conclude that muscle strength and muscle fatigue seem to decrease in FMS patients' both proximal and distal lower extremity muscles. © 2013 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

  9. Effects of isokinetic calf muscle exercise program on muscle strength and venous function in patients with chronic venous insufficiency.

    Science.gov (United States)

    Ercan, Sabriye; Çetin, Cem; Yavuz, Turhan; Demir, Hilmi M; Atalay, Yurdagül B

    2018-05-01

    Objective The aim of this study was to observe the change of the ankle joint range of motion, the muscle strength values measured with an isokinetic dynamometer, pain scores, quality of life scale, and venous return time in chronic venous insufficiency diagnosed patients by prospective follow-up after 12-week exercise program including isokinetic exercises. Methods The patient group of this study comprised 27 patients (23 female, 4 male) who were diagnosed with chronic venous insufficiency. An exercise program including isokinetic exercise for the calf muscle was given to patients three days per week for 12 weeks. At the end of 12 weeks, five of the patients left the study due to inadequate compliance with the exercise program. As a result, control data of 22 patients were included. Ankle joint range of active motion, isokinetic muscle strength, pain, quality of life, and photoplethysmography measurements were assessed before starting and after the exercise program. Results Evaluating changes of the starting and control data depending on time showed that all isokinetic muscle strength measurement parameters, range of motion, and overall quality of life values of patients improved. Venous return time values have also increased significantly ( p < 0.05). Conclusion In conclusion, increase in muscle strength has been provided with exercise therapy in patients with chronic venous insufficiency. It has been determined that the increase in muscle strength affected the venous pump and this ensured improvement in venous function and range of motion of the ankle. In addition, it has been detected that pain reduced and quality of life improved after the exercise program.

  10. Effects of the Competitive Season on the Isokinetic Muscle Parameters Changes in World-Class Handball Players.

    Science.gov (United States)

    Maurelli, Olivier; Bernard, Pierre L; Dubois, Romain; Ahmaidi, Said; Prioux, Jacques

    2018-05-25

    Maurelli, O, Bernard, PL, Dubois, R, Ahmaidi, S, and Prioux, J. Effects of the competitive season on the isokinetic muscle parameters changes in world-class handball players. J Strength Cond Res XX(X): 000-000, 2018-The aim of this study is to investigate the effects of the competitive season on isokinetic muscular parameters of the lower limbs in world-class handball players. Nineteen, male, world-class, handball players (age, 26.6 ± 5.4 years) participated in the study. Two bilateral isokinetic tests of knee joint flexors (H; hamstring) and extensors (Q; quadriceps) were performed in the beginning and end of the competitive season to determine the peak torque (PT), the mean power, and agonist-antagonist ratio, dominant-nondominant ratio (DNDR), and combined ratio. The results showed a significant decrease in PT values at low angular velocity (60°·s) in concentric mode for Q on dominant leg (p handball players. Accordingly, this study should help trainers to modify their planning to maximize strength and power qualities of the lower limbs of their players in addition to avoiding injuries.

  11. Shoulder isokinetic profile of male handball players of the Brazilian National Team

    Science.gov (United States)

    Andrade, Marília S.; Vancini, Rodrigo L.; de Lira, Claudio A. B.; Mascarin, Naryana C.; Fachina, Rafael J. F. G.; da Silva, Antonio C.

    2013-01-01

    Background Data obtained on an isokinetic dynamometer are useful to characterize muscle status and have been reported in muscle imbalance studies in different types of sport. However, few studies have assessed elite handball players to establish reference values. Objective The purpose of this study was to compare, for the dominant (D) and non-dominant (ND) side, the isokinetic profile of shoulder rotator muscle strength between male handball players (H) and asymptomatic non-athletes (NA). Method Isokinetic concentric and eccentric strength tests for D upper limbs were performed by the H group (n=20) and the NA group (n=12). Internal and external rotator muscle peak torque in concentric action was assessed at 60°/s and 300°/s and in eccentric action at 300°/s. We also calculated conventional balance (the ratio of external rotator peak torque to internal rotator peak torque in concentric action) and functional balance (the ratio of external rotator peak torque in eccentric action to internal rotator peak torque in concentric action). Results In the H group, dominant limbs were stronger in concentric action for external rotation at 60 and 300°/s. The conventional balance ratio for the D side was significantly lower at 60 and 300°/s for H compared to NA. The functional ratio for the D side was significantly lower at 300º/s for H compared to NA. Conclusions Compared to asymptomatic non-athletes, handball players presented significant muscular imbalance resulting from daily sports practice, a known risk factor for shoulder injuries. PMID:24271090

  12. Effect of eccentric isokinetic strengthening in the rehabilitation of patients with knee osteoarthritis: Isogo, a randomized trial

    Science.gov (United States)

    2014-01-01

    Background Femorotibial knee osteoarthritis is associated with muscle weakness in the lower limbs, particularly in the quadriceps, which results in disease progression. The interest of having muscular strengthening as part of the therapeutic arsenal for the medical treatment of knee osteoarthritis is now well established. The functional disability induced by knee osteoarthritis manifests itself principally when walking, notably downhill, during which the muscles are called upon to contract eccentrically. We can therefore think that eccentric muscular strengthening could bring a functional benefit that is superior to concentric muscular strengthening. Methods/Design This is a prospective, randomized, bicenter, parallel-group, international study. Eighty patients aged from 40 to 75 years old, suffering from medical-stage knee osteoarthritis, will undertake 6 weeks of isokinetic muscular strengthening. Randomization determines the mode of muscular strengthening: either exclusively eccentric or exclusively concentric. The principal objective is to demonstrate the superiority of the improvement in the quadriceps isokinetic torque after isokinetic muscular strengthening by the eccentric mode compared to the concentric mode. The following parameters are also evaluated: the variations in the level of pain, the parameters of walking (maximum speed over 10 and 200 meters, analysis on a computerized Gaitrite™ treadmill), static equilibrium (on a FUSYO™ force platform), and the functional status of the patient using the Western Ontario and MacMaster Universities osteoarthritis index (WOMAC) questionnaire after the strengthening period and at 6 months. Discussion A better knowledge of the most effective mode of muscular strengthening is needed to optimize the functional benefits to the patients. In case of superiority in terms of efficacy of the eccentric mode, the latter could be given priority in the rehabilitation treatment of knee osteoarthritis patients. Trial

  13. Determination of concentric and eccentric peak moment values for trunk flexion and extension in sedentary asymptomatic individuals by isokinetic dynamometry: a pilot study

    Directory of Open Access Journals (Sweden)

    Rafaella Stradiotto Bernardelli

    2017-11-01

    Full Text Available The spine has a direct influence on postural alignment and movement of the whole body. Lumbar muscles constitute a critical element in trunk performance while weakness of these muscles has been associated with low back pain. Hence, strength profiling of trunk muscles is clinically significant. The objective of this research was to determine, by means of isokinetic dynamometry, peak moment (PM values during isokinetic concentric and eccentric efforts of trunk flexion and extension in sedentary asymptomatic individuals. The sample consisted of 100 asymptomatic sedentary volunteers, fifty from each sex, aging 22.2 ± 3.3 years old. The sample underwent concentric and eccentric isokinetic assessment of the trunk flexor and extensor muscles at an angular velocity of 60 degrees/sec for each mode of contraction. The mean concentric PM for trunk flexion and extension were 139.5 and 166.6 Nm, respectively, while the respective values for the eccentric efforts were 188.8 and 221.2 Nm. The PM flexion/extension ratio was 0.87 and 0.89 for the concentric and eccentric efforts, respectively. These values of concentric and eccentric PM and PM ratio will serve as comparison parameters for future research, as well as for the assessment of symptomatic patients, and to help in the creation of the trunk muscle rebalance protocols.

  14. Tennis players show a lower coactivation of the elbow antagonist muscles during isokinetic exercises.

    Science.gov (United States)

    Bazzucchi, Ilenia; Riccio, Maria Elena; Felici, Francesco

    2008-10-01

    Previous studies have suggested that muscle coactivation could be reduced by a recurrent activity (training, daily activities). If this was correct, skilled athletes should show a specific muscle activation pattern with a low level of coactivation of muscles which are typically involved in their discipline. In particular, the aim of this study was to verify the hypothesis that the amount of antagonist activation of biceps brachii (BB) and triceps brachii (TB) is different between tennis players and non-players individuals during maximal isokinetic contractions. Ten young healthy men and eight male tennis players participated in the study. The surface electromyographic signals (sEMG) were recorded from the BB and TB muscles during three maximal voluntary isometric contractions (MVC) of elbow flexors and extensors and a set of three maximal elbow flexions and extensions at 15 degrees , 30 degrees , 60 degrees , 120 degrees , 180 degrees and 240 degrees /s. Normalized root mean square (RMS) of sEMG was calculated as an index of sEMG amplitude. Antagonist activation (%RMSmax) of TB was significantly lower in tennis players (from 14.0+/-7.9% at MVC to 16.3+/-8.9% at 240 degrees /s) with respect to non-players (from 27.7+/-19.7% at MVC to 38.7+/-17.6% at 240 degrees /s) at all angular velocities. Contrary to non-players, tennis players did not show any difference in antagonist activation between BB and TB muscles. Tennis players, with a constant practice in controlling forces around the elbow joint, learn how to reduce coactivation of muscles involved in the control of this joint. This has been shown by the lower antagonist muscular activity of triceps brachii muscle during isokinetic elbow flexion found in tennis players with respect to non-players.

  15. The effect of peculiar complex core balance training on isokinetic muscle functions of the knee and lumbus.

    Science.gov (United States)

    Lee, Myungsun; Han, Gunsoo

    2016-04-01

    [Purpose] This study aimed to investigate the effect of peculiar complex core balance training on the isokinetic muscle function of the knee joint and lumbus to provide fundamental data for establishing a training program that focuses on improving the performance and prevention of injury by developing the core and low extremity muscles. [Subjects and Methods] The participants in this study included a total of ten high school athletes involved in a throwing event for over five years. The subjects were randomly divided into two groups: The experimental group (N=5) and the control group (N=5). The experimental group underwent peculiar complex core balance training. [Results] According to the analysis of covariance, there was a significant effect of peculiar complex core balance training. Therefore, the isokinetic muscle function of the knee joint and lumbus in the experimental group participating in peculiar complex core balance training was significantly increased compared to the control group. [Conclusion] It is concluded that peculiar complex core balance training had a positive effect on the isokinetic muscle function of the knee and lumbus in throwing event athletes.

  16. [Chronic chondromalacia of the patella: comparison of morphological (magnetic resonance) and functional findings (isokinetic parameters) after rehabilitation].

    Science.gov (United States)

    Felicetti, G; Avanza, F; Fiori, M; Brignoli, E; Rovescala, R

    1996-01-01

    The knee is a common site for injuries of the cartilage, capsule and ligament, which calls for the use of noninvasive techniques to assess injury severity properly and to plan adequate rehabilitation. Our study was aimed at comparing MR with isokinetic findings. To this purpose, 40 patients were examined; they were all affected with chondromalacia patellae, grades I-III, previously diagnosed at arthroscopy. Namely, 8 patients had grade I and 32 grades II and III chondromalacia. After MR and isokinetic exams, all patients were submitted to a standardized rehabilitation program. Our results indicate a marked decrease in quadriceps strength, especially in the most severe cases; in less severe cases, recovery was complete at 6 months, while the deficit remained in grades II and III injuries. MR yield was not relevant in 4 of 8 cases, while isokinetic findings were negative in one case. Both methods were positive in the most severe cases. At 6 months, both functional and MR findings were normal in grade I injuries, while some alterations remained in the others.

  17. Isokinetic Strength Profile of Elite Female Handball Players

    Directory of Open Access Journals (Sweden)

    Xaverova Zuzana

    2015-12-01

    Full Text Available Systematic assessment of muscle strength of the lower extremities throughout the annual training cycle in athletes is crucial from a performance perspective for the optimization of the training process, as well as a health perspective with regard to injury prevention. The main aim of the present study was to determine isokinetic muscle strength of the knee flexors and extensors in female handball players at the beginning of a preparatory period and to assess whether there were any differences between players of different performance levels. The performance level was expressed by means of membership of the Women’s Junior National Handball Team (JNT, n=8 or the Women’s National Handball Team (NT, n=9. The isokinetic peak torque during concentric and eccentric single-joint knee flexion and extension was measured at angular velocities of 60, 180, 240°/s (concentric and 60°/s (eccentric. The Mann- Whitney test showed no significant differences in the peak torques or ipsilateral ratios between the two groups. The bilateral force deficit (BFD for concentric extension at 240°/s was significantly higher in the JNT compared with the NT (p=0.04; d=1.02. However, the results of individual evaluation show that the BFD was more frequent in the NT in most measurements. A high BFD was evident in the eccentric mode in both groups highlighting a need for particular strengthening. With regard to low strength ratios a prevention programme should be suggested for both observed groups of professional female handball players to reduce the risk of injury.

  18. Isokinetic Strength Profile of Elite Female Handball Players.

    Science.gov (United States)

    Xaverova, Zuzana; Dirnberger, Johannes; Lehnert, Michal; Belka, Jan; Wagner, Herbert; Orechovska, Karolina

    2015-12-22

    Systematic assessment of muscle strength of the lower extremities throughout the annual training cycle in athletes is crucial from a performance perspective for the optimization of the training process, as well as a health perspective with regard to injury prevention. The main aim of the present study was to determine isokinetic muscle strength of the knee flexors and extensors in female handball players at the beginning of a preparatory period and to assess whether there were any differences between players of different performance levels. The performance level was expressed by means of membership of the Women's Junior National Handball Team (JNT, n=8) or the Women's National Handball Team (NT, n=9). The isokinetic peak torque during concentric and eccentric single-joint knee flexion and extension was measured at angular velocities of 60, 180, 240°/s (concentric) and 60°/s (eccentric). The Mann-Whitney test showed no significant differences in the peak torques or ipsilateral ratios between the two groups. The bilateral force deficit (BFD) for concentric extension at 240°/s was significantly higher in the JNT compared with the NT (p=0.04; d=1.02). However, the results of individual evaluation show that the BFD was more frequent in the NT in most measurements. A high BFD was evident in the eccentric mode in both groups highlighting a need for particular strengthening. With regard to low strength ratios a prevention programme should be suggested for both observed groups of professional female handball players to reduce the risk of injury.

  19. THE EFFECT OF CREATINE SUPPLEMENTATION ON ATHLETE ISOKINETIC PERFORMANCE

    OpenAIRE

    Erkan Faruk ŞİRİN; Suzan YALÇIN

    2009-01-01

    The purpose of this study is to find the effects of Creatin Monohydrate (CrH2O) on athlete performance (isokinetic power measured as a total workout) used as an ergojenic aid in long-term (6 weeks) supplementation. There are 38 participants willing to join to the study. Their ages are between 20 and 27. All of them are choosed from active athletes. From the findings of this study; all the participants’ in the creatin group have increased the total workout production in all cycles of isokineti...

  20. Poor correlation between handgrip strength and isokinetic performance of knee flexor and extensor muscles in community-dwelling elderly women.

    Science.gov (United States)

    Felicio, Diogo Carvalho; Pereira, Daniele Sirineu; Assumpção, Alexandra Miranda; de Jesus-Moraleida, Fabianna Resende; de Queiroz, Barbara Zille; da Silva, Juscelio Pereira; de Brito Rosa, Naysa Maciel; Dias, João Marcos Domingues; Pereira, Leani Souza Máximo

    2014-01-01

    To investigate the correlation between handgrip strength and performance of knee flexor and extensor muscles determined using an isokinetic dynamometer in community-dwelling elderly women. This was a cross-sectional study. Sample selection for the study was made by convenience, and 221 (71.07 ± 4.93 years) community-dwelling elderly women were included. Knee flexor and extensor muscle performance was measured using an isokinetic dynamometer Biodex System 3 Pro. The isokinetic variables chosen for analysis were peak torque, peak torque/bodyweight, total work/bodyweight, total work, average power, and agonist/antagonist ratio at the angular velocities of 60°/s and 180°/s. Assessment of handgrip strength was carried out using the Jamar dynamometer. Spearman's correlation coefficient was calculated to identify intervariable correlations. Only knee flexor peak torque (60°/s) and average power (60°/s), and knee extensor peak torque (180°/s) and total work (180°/s) were significantly (P women. © 2013 Japan Geriatrics Society.

  1. Myocellular enzyme leakage, polymorphonuclear neutrophil activation and delayed onset muscle soreness induced by isokinetic eccentric exercise.

    Science.gov (United States)

    Croisier, J L; Camus, G; Deby-Dupont, G; Bertrand, F; Lhermerout, C; Crielaard, J M; Juchmès-Ferir, A; Deby, C; Albert, A; Lamy, M

    1996-01-01

    To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product prostaglandin E2 (PGE2). 10 healthy male subjects were submitted to eccentric and concentric isokinetic exercises on a Kin Trex device at 60 degrees/s angular velocity. Exercise consisted of 8 stages of 5 maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases. There was an interval of at least 30 days between eccentric and concentric testing, and the order of the two exercise sessions was randomly assigned. The subjective presence and intensity of DOMS was evaluated using a visual analogue scale, immediately, following 24 h and 48 h after each test. Five blood samples were drawn from an antecubital vein: at rest before exercise, immediately after, after 30 min recovery, 24 h and 48 h after the tests. The magnitude of the acute inflammatory response to exercise was assessed by measuring plasma levels of polymorphonuclear elastase ([EL]), myeloperoxidase ([MPO]) and PGE2 ([PGE2]). Using two way analysis of variance, it appeared that only eccentric exercise significantly increased [EL] and DOMS, especially of the hamstring muscles. Furthermore, a significant decrease in eccentric peak torque of this muscle group only was observed on day 2 after eccentric work (- 21%; P < 0.002). Serum activity of creatine kinase and serum concentration of myoglobin increased significantly 24 and 48 h after both exercise tests. However, these variables reached significantly higher values following eccentric contractions 48 h after exercise. Mean [PGE2] in the two exercise modes remained unchanged over time and were practically equal at each time point. On the basis of these findings, we conclude that the magnitude of polymorphonuclear (PMN) activation, muscle damage, and DOMS are greater after eccentric than after concentric muscle

  2. Isokinetic and isometric strength in osteoarthrosis of the knee. A comparative study with healthy women.

    Science.gov (United States)

    Tan, J; Balci, N; Sepici, V; Gener, F A

    1995-01-01

    Dynamic stability of the knee joint depends on the appropriate strength ratio of quadriceps and hamstring muscles. The purpose of this investigation was to determine the maximum peak torque (MPT) and MPT ratios of hamstrings to quadriceps (H/Q) muscles in patients with knee osteoarthritis (OA). Two groups of patients were included in the study. The first group consisted of 30 patients (Group A) with the clinical and radiologic findings of knee OA. The second group consisted of 30 patients (Group B) exhibiting knee joint pain without roentgenologic findings of knee OA. The findings of two patient groups were compared with each other and also with 30 healthy subjects (Group C). Isokinetic (at 60 degrees/s and at 180 degrees/s) and isometric (at 30 degrees and at 60 degrees of knee flexion) tests were performed by the rate-limiting isokinetic dynamometer system. Isokinetic and isometric MPT loss of knee flexors and extensors was found in both patient groups with respect to controls, but MPT ratios of H/Q muscles did not show a statistically significant difference compared with the control group. This may be related to the equal strength loss of knee flexors and knee extensors in patients with knee OA. It is concluded that strengthening exercises of hamstring muscles is as important as quadriceps strengthening in rehabilitation of knee OA.

  3. A Comparison of Isotonic, Isokinetic, and Plyometric Training Methods for Vertical Jump Improvement.

    Science.gov (United States)

    Miller, Christine D.

    This annotated bibliography documents three training methods used to develop vertical jumping ability and power: isotonic, isokinetics, and plyometric training. Research findings on all three forms of training are summarized and compared. A synthesis of conclusions drawn from the annotated writings is presented. The report includes a glossary of…

  4. Use of isokinetic muscle strength as a measure of severity of rheumatoid arthritis

    DEFF Research Database (Denmark)

    Schiøttz-Christensen, Berit; Lyngberg, K; Keiding, N

    2001-01-01

    The aim of this study was to study the association between isokinetic muscle strength (IMS) and other clinical indicators of disability and disease activity in patients with rheumatoid arthritis (RA). A cohort of 36 RA patients was followed over a 1-year period with five measurements of disease...

  5. Knee-joint proprioception during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training

    Science.gov (United States)

    Bernauer, E. M.; Walby, W. F.; Ertl, A. C.; Dempster, P. T.; Bond, M.; Greenleaf, J. E.

    1994-01-01

    To determine if daily isotonic exercise or isokinetic exercise training coupled with daily leg proprioceptive training, would influence leg proprioceptive tracking responses during bed rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a no-exercise (NOE) training control group (n = 5), and isotonic exercise (ITE, n = 7) and isokinetic exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min periods.d-1, 5 d.week-1. Only the IKE group performed proprioceptive training using a new isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pre-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p < 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9* +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.5%, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both isotonic exercise training (without additional proprioceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

  6. Knee-Joint Proprioception During 30-Day 6 deg Head-Down Bed Rest with Isotonic and Isokinetic Exercise Training

    Science.gov (United States)

    Bernauer, E. M.; Walby, W. F.; Ertl, A. C.; Dempster, P. T.; Bond, M.; Greenleaf, J. E.

    1994-01-01

    To determine if daily isotonic exercise or isokinetic exercise training coupled with daily log proprioceptive training, would influence log proprioceptive tracking responses during Bed Rest (BR), 19 men (36 +/- SD 4 years, 178 +/- 7 cm, 76.8 +/- 7.8 kg) were allocated into a NO-Exercise (NOE) training control group (n = 5), and IsoTanic Exercise (ITE, n = 7) and IsoKinetic Exercise (IKE, n = 7) training groups. Exercise training was conducted during BR for two 30-min period / d, 5 d /week. Only the IKE group performed proprioceptive training using a now isokinetic procedure with each lower extremity for 2.5 min before and after the daily exercise training sessions; proprioceptive testing occurred weekly for all groups. There were no significant differences in proprioceptive tracking scores, expressed as a percentage of the perfect score of 100, in the pro-BR ambulatory control period between the three groups. Knee extension and flexion tracking responses were unchanged with NOE during BR, but were significantly greater (*p less than 0.05) at the end of BR in both exercise groups when compared with NOE responses (extension: NOE 80.7 +/- 0.7%, ITE 82.9 +/- 0.6%, IKE 86.5* +/- 0.7%; flexion: NOE 77.6 +/- 1.50, ITE 80.0 +/- 0.8% (NS), IKE 83.6* +/- 0.8%). Although proprioceptive tracking was unchanged during BR with NOE, both lsotonic exercise training (without additional propriaceptive training) and especially isokinetic exercise training when combined with daily proprioceptive training, significantly improved knee proprioceptive tracking responses after 30 d of BR.

  7. Comparing passive angle-torque curves recorded simultaneously with a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments.

    Science.gov (United States)

    Buckner, Samuel L; Jenkins, Nathaniel D M; Costa, Pablo B; Ryan, Eric D; Herda, Trent J; Cramer, Joel T

    2015-05-01

    The purpose of the present study was to compare the passive angle-torque curves and the passive stiffness (PS, N m °(-)(1)) values recorded simultaneously from a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments in vivo. Nine healthy men (mean ± SD age = 21.4 ± 1.6 years) completed stretch tolerance assessments on a custom-built apparatus where passive torque was measured simultaneously from an isokinetic dynamometer and a load cell. Passive torque values that corresponded with the last 10° of dorsiflexion, verified by surface electromyographic amplitude, were analyzed for each device (θ1, θ2, θ3, …, θ10). Passive torque values measured with the load cell were greater (p ≤ 0.05) than the dynamometer torque values for θ4 through θ10. There were more statistical differentiations among joint angles for passive torque measured by the load cell, and the load cell measured a greater (p ≤ 0.01) increase in passive torque and PS than the isokinetic dynamometer. These findings suggested that when examining the angle-torque curves from passive dorsiflexion stretch tolerance tests, a load cell placed under the distal end of the foot may be more sensitive than the torque recorded from an isokinetic dynamometer. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  8. Experimental verification of air flow rate measurement for representative isokinetic air sampling in ventilation stacks

    International Nuclear Information System (INIS)

    Okruhlica, P.; Mrtvy, M.; Kopecky, Z.

    2009-01-01

    Nuclear facilities are obliged to monitor their discharge's influence on environment. Main monitored factions in NPP's ventilation stacks are usually noble gasses, particulates and iodine. These factions are monitored in air sampled from ventilation stack by means of sampling rosette and bypass followed with on-line measuring monitors and balance sampling devices with laboratory evaluations. Correct air flow rate measurement and representative iso-kinetic air sampling system is essential for physical correct and metrological accurate evaluation of discharge influence on environment. Pairs of measuring sensors (Anemometer, pressure gauge, thermometer and humidity meter) are symmetrically placed in horizontal projection of stack on positions based on measured air flow velocity distribution characteristic, Analogically diameter of sampling rosette nozzles and their placement in the middle of 6 - 7 annuluses are calculated for assurance of representative iso-kinetic sampling. (authors)

  9. Experimental verification of air flow rate measurement for representative isokinetic air sampling in ventilation stacks

    International Nuclear Information System (INIS)

    Okruhlica, P.; Mrtvy, M.; Kopecky, Z.

    2008-01-01

    Nuclear facilities are obliged to monitor their discharge's influence on environment. Main monitored factions in NPP's ventilation stacks are usually noble gasses, particulates and iodine. These factions are monitored in air sampled from ventilation stack by means of sampling rosette and bypass followed with on-line measuring monitors and balance sampling devices with laboratory evaluations. Correct air flow rate measurement and representative iso-kinetic air sampling system is essential for physical correct and metrological accurate evaluation of discharge influence on environment. Pairs of measuring sensors (Anemometer, pressure gauge, thermometer and humidity meter) are symmetrically placed in horizontal projection of stack on positions based on measured air flow velocity distribution characteristic, Analogically diameter of sampling rosette nozzles and their placement in the middle of 6- 7 annuluses are calculated for assurance of representative iso-kinetic sampling. (authors)

  10. Shoulder rotator isokinetic strength profile in young swimmers

    Directory of Open Access Journals (Sweden)

    Nuno Miguel Prazeres Batalha

    2012-08-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n5p545  Considering that some studies suggest that shoulder rotators muscle imbal­ances are related to joint pain and injury, and that there are no normative data for young swimmers, the aim of this study was: i to describe the muscle balance, fatigue and isokinetic strength profile of the shoulder rotators in young swimmers; ii to compare the results between swimmers and a group of young non-practitioners; iii to contribute to the acquisition of normative data of unilateral ratios of shoulder rotators. We evaluated the shoulder rotators concentric strength and unilateral ratios (ratio between torque of external and internal rotators of 60 swimmers (age: 14.55 ± 0.5 years old; body mass: 61.16 ± 7.08 kg and 60 non-practitioners (age: 14.62 ± 0.49 years old; body mass: 60.22 ± 10.01 kg. The evaluation was performed in the sitting position (90° abduction and elbow flexion at 60º.s-1 and 180º.s-1 angular speeds using an isokinetic dynamometer (Biodex System 3. The results of the fatigue ratios revealed no differences between the groups. Swimmers showed unilateral ratios of 73.39 ± 17.26% in the dominant limb (DL and 77.89 ± 15,23% in the non-dominant limb (NDL for assessments at 60º.s-1. At 180º.s-1, ratios were 74.77± 13.99% for DL and 70.11 ± 14.57% for NDL. Swimmers presented greater muscle imbalance, and differed from non-practitioners in the ability to produce power with the internal rotators, which was significantly higher in the former group.

  11. Quadriceps Strength in Patients With Isolated Cartilage Defects of the Knee: Results of Isokinetic Strength Measurements and Their Correlation With Clinical and Functional Results.

    Science.gov (United States)

    Hirschmüller, Anja; Andres, Tasja; Schoch, Wolfgang; Baur, Heiner; Konstantinidis, Lukas; Südkamp, Norbert P; Niemeyer, Philipp

    2017-05-01

    Recent studies have found a significant deficit of maximum quadriceps strength after autologous chondrocyte implantation (ACI) of the knee. However, it is unclear whether muscular strength deficits in patients with cartilage damage exist prior to operative treatment. To isokinetically test maximum quadriceps muscle strength and quantify the impact of possible strength deficits on functional and clinical test results. Cross-sectional study; Level of evidence, 3. To identify clinically relevant muscular strength deficits, 24 patients (5 females, 19 males; mean age, 34.5 years; body mass index, 25.9 kg/m 2 ) with isolated cartilage defects (mean onset, 5.05 years; SD, 7.8 years) in the knee joint underwent isokinetic strength measurements. Maximal quadriceps strength was recorded in 3 different testing modes: pure concentric contraction (flexors and extensors alternating work; con1), concentric-eccentric (only the extensors work concentrically and eccentrically; con2), and eccentric contraction in the alternating mode (ecc). Results were compared for functional performance (single-leg hop test), pain scales (visual analog scale [VAS], numeric rating scale [NRS]), self-reported questionnaires (International Knee Documentation Committee [IKDC], Knee Injury and Osteoarthritis Outcome Scale [KOOS]), and defect size (cm 2 ). Compared with the uninjured leg, significantly lower quadriceps strength was detected in the injured leg in all isokinetic working modes (con1 difference, 27.76 N·m [SD 17.47; P = .003]; con2 difference, 21.45 N·m [SD, 18.45; P =.025]; ecc difference, 29.48 N·m [SD, 21.51; P = .001]), with the largest deficits found for eccentric muscle performance. Moderate negative correlations were observed for the subjective pain scales NRS and VAS. The results of the IKDC and KOOS questionnaires showed low, nonsignificant correlations with findings in the isokinetic measurement. Moreover, defect sizes (mean, 3.13 cm 2 ) were of no importance regarding the

  12. Hamstring and Quadriceps Isokinetic Strength Deficits Are Weak Risk Factors for Hamstring Strain Injuries: A 4-Year Cohort Study.

    Science.gov (United States)

    van Dyk, Nicol; Bahr, Roald; Whiteley, Rodney; Tol, Johannes L; Kumar, Bhavesh D; Hamilton, Bruce; Farooq, Abdulaziz; Witvrouw, Erik

    2016-07-01

    A hamstring strain injury (HSI) has become the most common noncontact injury in soccer. Isokinetic muscle strength deficits are considered a risk factor for HSIs. However, underpowered studies with small sample sizes unable to determine small associations have led to inconclusive results regarding the role of isokinetic strength and strength testing in HSIs. To examine whether differences in isokinetic strength measures of knee flexion and extension represent risk factors for hamstring injuries in a large cohort of professional soccer players in an adequately powered study design. Cohort study; Level of evidence, 2. A total of 614 professional soccer players from 14 teams underwent isokinetic strength testing during preseason screening. Testing consisted of concentric knee flexion and extension at 60 deg/s and 300 deg/s and eccentric knee extension at 60 deg/s. A clustered multiple logistic regression analysis was used to identify variables associated with the risk of HSIs. Receiver operating characteristic (ROC) curves were calculated to determine sensitivity and specificity. Of the 614 players, 190 suffered an HSI during the 4 seasons. Quadriceps concentric strength at 60 deg/s (odds ratio [OR], 1.41; 95% CI, 1.03-1.92; P = .03) and hamstring eccentric strength at 60 deg/s (OR, 1.37; 95% CI, 1.01-1.85; P = .04) adjusted for bodyweight were independently associated with the risk of injuries. The absolute differences between the injured and uninjured players were 6.9 N·m and 9.1 N·m, with small effect sizes (d hamstring eccentric strength, respectively, indicating a failed combined sensitivity and specificity of the 2 strength variables identified in the logistic regression models. This study identified small absolute strength differences and a wide overlap of the absolute strength measurements at the group level. The small associations between lower hamstring eccentric strength and lower quadriceps concentric strength with HSIs can only be considered as weak

  13. Gas exchange kinetics following concentric-eccentric isokinetic arm and leg exercise.

    Science.gov (United States)

    Drescher, U; Mookerjee, S; Steegmanns, A; Knicker, A; Hoffmann, U

    2017-06-01

    To evaluate the effects of exercise velocity (60, 150, 240deg∙s -1 ) and muscle mass (arm vs leg) on changes in gas exchange and arterio-venous oxygen content difference (avDO 2 ) following high-intensity concentric-eccentric isokinetic exercise. Fourteen subjects (26.9±3.1years) performed a 3×20-repetition isokinetic exercise protocol. Recovery beat-to-beat cardiac output (CO) and breath-by-breath gas exchange were recorded to determine post-exercise half-time (t 1/2 ) for oxygen uptake (V˙O 2 pulm), carbon dioxide output (V˙CO 2 pulm), and ventilation (V˙ E ). Significant differences of the t 1/2 values were identified between 60 and 150deg∙s -1 . Significant differences in the t 1/2 values were observed between V˙O 2 pulm and V˙CO 2 pulm and between V˙CO 2 pulm and V˙ E . The time to attain the first avDO 2 -peak showed significant differences between arm and leg exercise. The present study illustrates, that V˙O 2 pulm kinetics are distorted due to non-linear CO dynamics. Therefore, it has to be taken into account, that V˙O 2 pulm may not be a valuable surrogate for muscular oxygen uptake kinetics in the recovery phases. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Effects of the application of ankle functional rehabilitation exercise on the ankle joint functional movement screen and isokinetic muscular function in patients with chronic ankle sprain.

    Science.gov (United States)

    Ju, Sung-Bum; Park, Gi Duck

    2017-02-01

    [Purpose] This study was conducted to investigate the effects of ankle functional rehabilitation exercise on ankle joint functional movement screen results and isokinetic muscular function in patients with chronic ankle sprain patients. [Subjects and Methods] In this study, 16 patients with chronic ankle sprain were randomized to an ankle functional rehabilitation exercise group (n=8) and a control group (n=8). The ankle functional rehabilitation exercise centered on a proprioceptive sense exercise program, which was applied 12 times for 2 weeks. To verify changes after the application, ankle joint functional movement screen scores and isokinetic muscular function were measured and analyzed. [Results] The ankle functional rehabilitation exercise group showed significant improvements in all items of the ankle joint functional movement screen and in isokinetic muscular function after the exercise, whereas the control group showed no difference after the application. [Conclusion] The ankle functional rehabilitation exercise program can be effectively applied in patients with chronic ankle sprain for the improvement of ankle joint functional movement screen score and isokinetic muscular function.

  15. Isokinetic strength effects of FIFA'a "The 11+" injury prevention training programme

    DEFF Research Database (Denmark)

    Brito, João; Figueiredo, Pedro; Fernandes, Luís

    2010-01-01

    The purpose of this study was to evaluate whether FIFA's Medical Assessment and Research Centre (F-MARC) injury prevention programme, "The 11+", improves isokinetic strength of the knee extensor and flexor muscles in sub-elite soccer players. Twenty players aged 22.3 ± 4.2 yr performed "The 11+" 3...... significantly improved the conventional H/Q ratio at 60°/s by 14.8{\\%} and the DCR by 13.8% in the non-dominant limb (pknee joint....

  16. Isokinetic strength testing does not predict hamstring injury in Australian Rules footballers

    OpenAIRE

    Bennell, K.; Wajswelner, H.; Lew, P.; Schall-Riaucour, A.; Leslie, S.; Plant, D.; Cirone, J.

    1998-01-01

    OBJECTIVE: To determine the relation of hamstring and quadriceps muscle strength and imbalance to hamstring injury using a prospective observational cohort study METHOD: A total of 102 senior male Australian Rules footballers aged 22.2 (3.6) years were tested at the start of a football season. Maximum voluntary concentric and eccentric torque of the hamstring and quadriceps muscles of both legs was assessed using a Kin-Com isokinetic dynamometer at angular velocities of 60 and 180 degre...

  17. Combined Effects of Lignosus rhinocerotis Supplementation and Resistance Training on Isokinetic Muscular Strength and Power, Anaerobic and Aerobic Fitness Level, and Immune Parameters in Young Males.

    Science.gov (United States)

    Chen, Chee Keong; Hamdan, Nor Faeiza; Ooi, Foong Kiew; Wan Abd Hamid, Wan Zuraida

    2016-01-01

    This study investigated the effects of Lignosus rhinocerotis (LRS) supplementation and resistance training (RT) on isokinetic muscular strength and power, anaerobic and aerobic fitness, and immune parameters in young males. Participants were randomly assigned to four groups: Control (C), LRS, RT, and combined RT-LRS (RT-LRS). Participants in the LRS and RT-LRS groups consumed 500 mg of LRS daily for 8 weeks. RT was conducted 3 times/week for 8 weeks for participants in the RT and RT-LRS groups. The following parameters were measured before and after the intervention period: Anthropometric data, isokinetic muscular strength and power, and anaerobic and aerobic fitness. Blood samples were also collected to determine immune parameters. Isokinetic muscular strength and power were increased ( P anaerobic power and capacity and aerobic fitness in this group. Similarly, RT group had increases ( P anaerobic power and capacity, aerobic fitness, T lymphocytes (CD3 and CD4), and B lymphocytes (CD19) counts were observed in the RT group. RT elicited increased isokinetic muscular strength and power, anaerobic and aerobic fitness, and immune parameters among young males. However, supplementation with LRS during RT did not provide additive benefits.

  18. Influence of functional knee bracing on the isokinetic and functional tests of anterior cruciate ligament deficient patients.

    Directory of Open Access Journals (Sweden)

    Niyousha Mortaza

    Full Text Available Use of functional knee braces has been suggested to provide protection and to improve kinetic performance of the knee in Anterior cruciate ligament(ACL-injured patients. However, many athletes might refrain from wearing the braces because of the fear of performance hindrance in the playing field. The aim of this study was to examine the effect of three functional knee brace/sleeves upon the isokinetic and functional performance of ACL-deficient and healthy subjects. Six anterior cruciate ligament deficient (29.0 ± 5.3 yrs., 175.2 ± 5.4 cm, and 73.0 ± 10.0 kg and six healthy male subjects (27.2 ± 3.7 yrs., 176.4 ± 6.4 cm, and 70.3 ± 6.9 kg were selected. The effect of a custom-made functional knee brace, and two neoprene knee sleeves, one with four metal supports and one without support were examined via the use of isokinetic and functional tests in four sets (non-braced,wearing functional knee brace,and wearing the sleeves. Cross-over hop and single leg vertical jump test were performed and jump height, and hop distance were recorded. Peak torque to body weight ratio and average power in two isokinetic velocities(60°.s(-1,180°.s(-1 were recorded and the brace/sleeves effect was calculated as the changes in peak torque measured in the brace/sleeves conditions, expressed as a percentage of peak torque measured in non-braced condition. Frequency content of the isokinetic torque-time curves was also analyzed. Wilcoxon signed rank test was used to compare the measured values in four test conditions within each control and ACL-deficient group,and Mann-Whitney U test was used for the comparison between the two groups. No significant differences in peak torque, average power, torque-time curve frequency content, vertical-jump and hop measurements were found within the experimental and the non-braced conditions (p>0.05. Although the examined functional knee brace/sleeves had no significant effect on the knee muscle performance, there have been

  19. At return to play following hamstring injury the majority of professional football players have residual isokinetic deficits

    NARCIS (Netherlands)

    Tol, Johannes L.; Hamilton, Bruce; Eirale, Cristiano; Muxart, Patrice; Jacobsen, Philipp; Whiteley, Rod

    2014-01-01

    There is an ongoing debate regarding the optimal criteria for return to sport after an acute hamstring injury. Less than 10% isokinetic strength deficit is generally recommended but this has never been documented in professional football players after rehabilitation. Our aim was to evaluate

  20. The Total Work Measured During a High Intensity Isokinetic Fatigue Test Is Associated With Anaerobic Work Capacity

    Directory of Open Access Journals (Sweden)

    Laurent Bosquet, Kenan Gouadec, Nicolas Berryman, Cyril Duclos, Vincent Gremeaux, Jean Louis Croisier

    2016-03-01

    Full Text Available The purpose of the study was to determine whether total work measured during a high intensity isokinetic fatigue test (TWFAT could be considered as a valid measure of anaerobic work capacity (AWC, such as determined by total work measured during a Wingate Anaerobic Test (TWWAnT. Twenty well-trained cyclists performed 2 randomly ordered sessions involving a high intensity isokinetic fatigue test consisting in 30 reciprocal maximal concentric contractions of knee flexors and extensors at 180°·s-1, and a Wingate Anaerobic Test. We found that TWFAT of knee extensors was largely lower than TWWAnT (4151 ± 691 vs 22313 ± 2901 J, respectively, p < 0.05, Hedge’s g = 4.27. Both measures were highly associated (r = 0.83, and the 95% limits of agreement (LoA represented 24.5% of TWWAnT. TWFAT of knee flexors (2151 ± 540 J was largely lower than TWWAnT (p < 0.05, g = 9.52. By contrast, both measures were not associated (r = 0.09, and the 95% LoA represented 31.1% of TWWAnT. Combining TWFAT of knee flexors and knee extensors into a single measure (6302 ± 818 J did not changed neither improved these observations. We still found a large difference with TWWAnT (p < 0.05, g = 5.26, a moderate association (r = 0.65 and 95% LoA representing 25.5% of TWWAnT. We concluded that TWFAT of knee extensors could be considered as a valid measure of AWC, since both measure were highly associated. However, the mean difference between both measures and their 95% LoA were too large to warrant interchangeability.

  1. Comparison of whole-body vibration exercise and plyometric exercise to improve isokinetic muscular strength, jumping performance and balance of female volleyball players.

    Science.gov (United States)

    Kim, Yong-Youn; Park, Si-Eun

    2016-11-01

    [Purpose] The purpose of this study was to assess the effect of whole-body vibration exercise and plyometric exercise on female volleyball players. [Subjects and Methods] Subjects were randomly allocated to two exercise groups (whole-body vibration exercise group and plyometric exercise group). The exercise was conducted three times each week for 8 weeks. Isokinetic muscular strength, jumping performance, and balance were measured before starting the exercise and after finishing the 8 weeks of exercise. [Results] Measurements of isokinetic muscular strength revealed that the whole-body vibration exercise group showed significant increase after the exercise. However, the plyometric exercise group had no significant increase in lumbar flexion, extension, and knee flexion. Measurements of vertical jumping revealed that, the whole-body vibration exercise group had no significant increase after the exercise. However, the plyometric exercise group showed significant increase. Measurements of balance revealed that, the whole-body vibration exercise group showed significant increase. However, the plyometric exercise group showed no significant increase. [Conclusion] Although both whole-body vibration and plyometric exercises are effective intervention methods, the two methods have different effects on the improvement of isokinetic muscular strength, jumping performance, and balance of female volleyball players.

  2. Isokinetic hamstrings-to-quadriceps peak torque ratio: the influence of sport modality, gender, and angular velocity.

    Science.gov (United States)

    Andrade, Marilia Dos Santos; De Lira, Claudio Andre Barbosa; Koffes, Fabiana De Carvalho; Mascarin, Naryana Cristina; Benedito-Silva, Ana Amélia; Da Silva, Antonio Carlos

    2012-01-01

    The purpose of this study was to determine differences in hamstrings-to-quadriceps (H/Q) peak torque ratios evaluated at different angular velocities between men and women who participate in judo, handball or soccer. A total of 166 athletes, including 58 judokas (26 females and 32 males), 39 handball players (22 females and 17 males), and 69 soccer players (17 females and 52 males), were evaluated using an isokinetic dynamometer. The H/Q isokinetic peak torque ratios were calculated at angular velocities of 1.05 rad · s⁻¹ and 5.23 rad · s⁻¹. In the analysis by gender, female soccer players produced lower H/Q peak torque ratios at 1.05 rad · s⁻¹ than males involved in the same sport. However, when H/Q peak torque ratio was assessed at 5.23 rad · s⁻¹, there were no significant differences between the sexes. In the analysis by sport, there were no differences among females at 1.05 rad · s⁻¹. In contrast, male soccer players had significantly higher H/Q peak torque ratios than judokas (66 ± 12% vs. 57 ± 14%, respectively). Female handball players produced significantly lower peak torque ratios at 5.23 rad · s⁻¹ than judokas or soccer players, whereas males presented no ratio differences among sports At 5.23 rad · s⁻¹. In the analysis by velocity, women's muscular ratios assessed at 1.05 rad · s⁻¹ were significantly lower than at 5.23 rad · s⁻¹ for all sports; among men, only judokas presented lower ratios at 1.05 rad · s⁻¹ than at 5.23 rad · s⁻¹. The present results suggest that sport modality and angular velocity influence the isokinetic strength profiles of men and women.

  3. Comparison of isokinetic muscle strength and muscle power by types of warm-up.

    Science.gov (United States)

    Sim, Young-Je; Byun, Yong-Hyun; Yoo, Jaehyun

    2015-05-01

    [Purpose] The purpose of this study was to clarify the influence of static stretching at warm-up on the isokinetic muscle torque (at 60°/sec) and muscle power (at 180°/sec) of the flexor muscle and extensor muscle of the knee joint. [Subjects and Methods] The subjects of this study were 10 healthy students with no medically specific findings. The warm-up group and warm-up with stretching group performed their respective warm-up prior to the isokinetic muscle torque evaluation of the knee joint. One-way ANOVA was performed by randomized block design for each variable. [Results] The results were as follows: First, the flexor peak torque and extensor peak torque of the knee joint tended to decrease at 60°/sec in the warm-up with stretching group compared with the control group and warm-up group, but without statistical significance. Second, extensor power at 180°/sec was also not statistically significant. However, it was found that flexor power increased significantly in the warm-up with stretching group at 180°/sec compared with the control group and warm-up group in which stretching was not performed. [Conclusion] Therefore, it is considered that in healthy adults, warm-up including two sets of stretching for 20 seconds per muscle group does not decrease muscle strength and muscle power.

  4. Isokinetic strength assessment offers limited predictive validity for detecting risk of future hamstring strain in sport: a systematic review and meta-analysis.

    Science.gov (United States)

    Green, Brady; Bourne, Matthew N; Pizzari, Tania

    2018-03-01

    To examine the value of isokinetic strength assessment for predicting risk of hamstring strain injury, and to direct future research into hamstring strain injuries. Systematic review. Database searches for Medline, CINAHL, Embase, AMED, AUSPORT, SPORTDiscus, PEDro and Cochrane Library from inception to April 2017. Manual reference checks, ahead-of-press and citation tracking. Prospective studies evaluating isokinetic hamstrings, quadriceps and hip extensor strength testing as a risk factor for occurrence of hamstring muscle strain. Independent search result screening. Risk of bias assessment by independent reviewers using Quality in Prognosis Studies tool. Best evidence synthesis and meta-analyses of standardised mean difference (SMD). Twelve studies were included, capturing 508 hamstring strain injuries in 2912 athletes. Isokinetic knee flexor, knee extensor and hip extensor outputs were examined at angular velocities ranging 30-300°/s, concentric or eccentric, and relative (Nm/kg) or absolute (Nm) measures. Strength ratios ranged between 30°/s and 300°/s. Meta-analyses revealed a small, significant predictive effect for absolute (SMD=-0.16, P=0.04, 95% CI -0.31 to -0.01) and relative (SMD=-0.17, P=0.03, 95% CI -0.33 to -0.014) eccentric knee flexor strength (60°/s). No other testing speed or strength ratio showed statistical association. Best evidence synthesis found over half of all variables had moderate or strong evidence for no association with future hamstring injury. Despite an isolated finding for eccentric knee flexor strength at slow speeds, the role and application of isokinetic assessment for predicting hamstring strain risk should be reconsidered, particularly given costs and specialised training required. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  5. Learning effect of isokinetic measurements in healthy subjects, and reliability and comparability of Biodex and Lido dynamometers

    DEFF Research Database (Denmark)

    Lund, Hans; Søndergaard, K; Zachariassen, T

    2005-01-01

    The aim of this study was to examine the learning effect during a set of isokinetic measurements, to evaluate the reliability of the Biodex System 3 PRO dynamometer, and to compare the Biodex System 3 PRO and the Lido Active dynamometers on both extension and flexion over the elbow and the knee a...

  6. Hamstring and Quadriceps Isokinetic Strength Deficits Are Weak Risk Factors for Hamstring Strain Injuries: A 4-Year Cohort Study

    NARCIS (Netherlands)

    van Dyk, Nicol; Bahr, Roald; Whiteley, Rodney; Tol, Johannes L.; Kumar, Bhavesh D.; Hamilton, Bruce; Farooq, Abdulaziz; Witvrouw, Erik

    2016-01-01

    A hamstring strain injury (HSI) has become the most common noncontact injury in soccer. Isokinetic muscle strength deficits are considered a risk factor for HSIs. However, underpowered studies with small sample sizes unable to determine small associations have led to inconclusive results regarding

  7. No Differences Between Alter G-Trainer and Active and Passive Recovery Strategies on Isokinetic Strength, Systemic Oxidative Stress and Perceived Muscle Soreness After Exercise-Induced Muscle Damage.

    Science.gov (United States)

    Cooke, Matthew B; Nix, Carrie M; Greenwood, Lori D; Greenwood, Mike C

    2018-03-01

    Cooke, MB, Nix, C, Greenwood, L, and Greenwood, M. No Differences Between Alter G-Trainer and Active and Passive Recovery Strategies on Isokinetic Strength, Systemic Oxidative Stress and Perceived Muscle Soreness After Exercise-Induced Muscle Damage. J Strength Cond Res 32(3): 736-747, 2018-The incidence of muscle injuries is prevalent in elite sport athletes and weekend warriors and strategies that safely and effectively hasten recovery are highly desirable. The purpose of this study was to examine the differences between 3 recovery methods after eliciting muscle damage in recreationally active men relative to maximal isokinetic contractions, perceived muscle soreness, and psychological mood states. Twenty-five recreationally active men (22.15 ± 3.53 years, 75.75 ± 11.91 kg, 180.52 ± 7.3 cm) were randomly matched by V[Combining Dot Above]O2 peak (53.86 ± 6.65 ml·kg·min) and assigned to one of 3 recovery methods: anti-gravity treadmill (G-Trainer) (N = 8), conventional treadmill (N = 8) or static stretching (N = 9). Recovery methods were performed 30 minutes, 24, 48, and 72 hours after a 45-minute downhill run. Following eccentrically biased running, no significant differences were noted in isokinetic knee flexion and extension peak torque, systemic markers of muscle damage, oxidative stress and lipid peroxidation such as serum creatine kinase (CK), superoxide dismutase (SOD), and malondialdehyde (MDA), respectively, and subjective ratings of perceived muscle soreness between recovery methods. The G-Trainer group did however display a higher mood state as indicated by the Profile of Mood State global scores at 24 hours postexercise when compared to the conventional treadmill recovery group (p = 0.035). The improved mood state after the use of the anti-gravity treadmill may provide clinical relevance to other populations.

  8. Isokinetic peak torque and flexibility changes of the hamstring muscles after eccentric training: Trained versus untrained subjects.

    Science.gov (United States)

    Abdel-Aziem, Amr Almaz; Soliman, Elsadat Saad; Abdelraouf, Osama Ragaa

    2018-05-23

    The aim of this study was to examine the effect of eccentric isotonic training on hamstring flexibility and eccentric and concentric isokinetic peak torque in trained and untrained subjects. Sixty healthy subjects (mean age: 21.66 ± 2.64) were divided into three equal groups, each with 20 voluntary participants. Two experimental groups (untrained and trained groups) participated in a hamstring eccentric isotonic strengthening program (five days/week) for a six-week period and one control group that was not involved in the training program. The passive knee extension range of motion and hamstring eccentric and concentric isokinetic peak torque were measured at angular velocities 60° and 120°/s for all groups before and after the training period. Two-way analysis of variance showed that there was a significant increase in the hamstring flexibility of the untrained and trained groups (25.65 ± 6.32°, 26.55 ± 5.99°, respectively), (p  0.05). Moreover, there was a significant increase in eccentric isokinetic peak torque of both the untrained and trained groups (127.25 ± 22.60Nm, 139.65 ± 19.15Nm, 125.40 ± 21.61Nm, 130.90 ± 18.71Nm, respectively), (p  0.05) at both angular velocities. On the other hand, there was no significant increase in the concentric isokinetic peak torque of the three groups (92.50 ± 20.50Nm, 79.05 ± 18.95Nm, 92.20 ± 21.96Nm, 79.85 ± 18.97Nm, 100.45 ± 25.78Nm, 83.40 ± 23.73Nm, respectively), (p > 0.05) at both angular velocities. The change scores in the hamstring flexibility (06.25 ± 1.86°) and eccentric peak torque of the untrained group (16.60 ± 4.81Nm, 17.45 ± 5.40Nm, respectively) were significantly higher (p  0.05). After a six-week period of eccentric isotonic training, the hamstring eccentric peak torque and flexibility of trained and untrained groups improved without changes in the concentric peak torque. Moreover, the improvement of untrained subjects was higher than trained

  9. Profile of isokinetic eccentric-to-concentric strength ratios of shoulder rotator muscles in elite female team handball players.

    Science.gov (United States)

    Andrade, Marilia Dos Santos; Fleury, Anna Maria; de Lira, Claudio Andre Barbosia; Dubas, Joao Paulo; da Silva, Antonio Carlos

    2010-05-01

    The purpose of this study was to establish the isokinetic profile of shoulder rotator muscles strength in female handball players. Twenty-seven handball players performed concentric and eccentric strength tests of both dominant and non-dominant upper limbs on an isokinetic dynamometer. Internal and external rotator muscles peak torque was assessed at 1.05, 3.14, and 5.23 rad . s(-1) in concentric mode and at 3.14 and 5.23 rad . s(-1) in eccentric mode. Concentric balance ratio and functional ratio were obtained. Bi-lateral deficiency was compared. Concentric strength for internal and external rotation was significantly greater for the dominant than for the non-dominant limb for all speeds (P muscles were stronger in the dominant than the non-dominant limb (P stronger than the non-dominant side, balance concentric ratios remained the same, with only the functional strength ratio different at 5.23 rad . s(-1). Our results suggest that concentric strength exercises be used for internal and external rotators on the non-dominant side, and functional exercise that improves eccentric rotation strength for prevention programmes.

  10. The LISST-SL streamlined isokinetic suspended-sediment profiler

    Science.gov (United States)

    Gray, John R.; Agrawal, Yogesh C.; Pottsmith, H. Charles

    2004-01-01

    The new manually deployed Laser In Situ Scattering Transmissometer-StreamLined profiler (LISST-SL) represents a major technological advance for suspended-sediment measurements in rivers. The LISST-SL is being designed to provide real-time data on sediment concentrations and particle-size distributions. A pressure sensor and current meter provide real-time depth and ambient velocity data, respectively. The velocity data are also used to control pumpage across an internal laser so that the intake velocity is constantly adjusted to match the ambient stream velocity. Such isokinetic withdrawal is necessary for obtaining representative sedimentary measurements in streamflow, and ensures compliance with established practices. The velocity and sediment-concentration data are used to compute fluxes for up to 32 particle-size classes at points, verticals, or in the entire stream cross section. All data are stored internally, as well as transmitted via a 2-wire conductor to the operator using a specially developed communication protocol. The LISST-SL's performance will be measured and compared to published sedimentological accuracy criteria, and a performance summary will be placed on-line.

  11. Analysis of isokinetic muscle function and postural control in individuals with intermittent claudication

    Directory of Open Access Journals (Sweden)

    Morgan Lanzarin

    2016-02-01

    Full Text Available BACKGROUND: Intermittent claudication (IC is a debilitating condition that mostly affects elderly people. IC is manifested by a decrease in ambulatory function. Individuals with IC present with motor and sensory nerve dysfunction in the lower extremities, which may lead to deficits in balance. OBJECTIVE: This study aimed to measure postural control and isokinetic muscle function in individuals with intermittent claudication. METHOD: The study included 32 participants of both genders, 16 IC participants (mean age: 64 years, SD=6 and 16 healthy controls (mean age: 67 years, SD=5, which were allocated into two groups: intermittent claudication group (ICG and control group (CG. Postural control was assessed using the displacement and velocity of the center of pressure (COP during the sensory organization test (SOT and the motor control test (MCT. Muscle function of the flexor and extensor muscles of the knee and ankle was measured by an isokinetic dynamometer. Independent t tests were used to calculate the between-group differences. RESULTS: The ICG presented greater displacement (p =0.027 and speed (p =0.033 of the COP in the anteroposterior direction (COPap during the MCT, as well as longer latency (p =0.004. There were no between-group differences during the SOT. The ICG showed decreased muscle strength and power in the plantar flexors compared to the CG. CONCLUSION: Subjects with IC have lower values of strength and muscle power of plantiflexores, as well as changes in postural control in dynamic conditions. These individuals may be more vulnerable to falls than healthy subjects.

  12. The Effect of Ankle, Knee and Hip Isokinetic Fatigue on Shock Absorption and Rate of Loading during Pair-leg Landing

    Directory of Open Access Journals (Sweden)

    Hamideh Khodaveisi

    2016-12-01

    Conclusion: Findings of this study indicate that the fatigue protocol using Isokinetic devices with uniform speed, increases muscle strength due to generating stress at all the joints, thereby, compensating the active and passive joints for shock absorption, and load distribution on the lower extremities. 

  13. Intrarater reliability of the Humac NORM isokinetic dynamometer for strength measurements of the knee and shoulder muscles.

    Science.gov (United States)

    Habets, Bas; Staal, J Bart; Tijssen, Marsha; van Cingel, Robert

    2018-01-10

    To determine the intrarater reliability of the Humac NORM isokinetic dynamometer for concentric and eccentric strength tests of knee and shoulder muscles. 54 participants (50% female, average age 20.9 ± 3.1 years) performed concentric and eccentric strength measures of the knee extensors and flexors, and the shoulder internal and external rotators on two different Humac NORM isokinetic dynamometers, which were situated at two different centers. The knee extensors and flexors were tested concentrically at 60° and 180°/s, and eccentrically at 60° s. Concentric strength of the shoulder internal and external rotators, and eccentric strength of the external rotators were measured at 60° and 120°/s. We calculated intraclass correlation coefficients (ICCs), standard error of measurement, standard error of measurement expressed as a %, and the smallest detectable change to determine reliability and measurement error. ICCs for the knee tests ranged from 0.74 to 0.89, whereas ICC values for the shoulder tests ranged from 0.72 to 0.94. Measurement error was highest for the concentric test of the knee extensors and lowest for the concentric test of shoulder external rotators.

  14. Effects of photobiomodulation on the fatigue level in elderly women: an isokinetic dynamometry evaluation.

    Science.gov (United States)

    Vassão, P G; Toma, R L; Antunes, H K M; Tucci, H T; Renno, A C M

    2016-02-01

    Aging is responsible by a series of morphological and functional modifications that lead to a decline of muscle function, particularly in females. Muscle tissue in elderly people is more susceptible to fatigue and, consequently, to an increased inability to maintain strength and motor control. In this context, therapeutic approaches able of attenuating muscle fatigue have been investigated. Among these, the photobiomodulation demonstrate positive results to interacts with biological tissues, promoting the increase in cell energy production. Thus, the aim of this study was to investigate the effects of photobiomodulation (808 nm, 250 J/cm(2), 100 mW, 7 J each point) in the fatigue level and muscle performance in elderly women. Thirty subjects entered a crossover randomized double-blinded placebo-controlled trial. Photobiomodulation was delivered on the rectus femoris muscle of the dominant limb immediately before the fatigue protocol. In both sessions, peripheral muscle fatigue was analyzed by surface electromyography (EMG) and blood lactate analysis. Muscle performance was evaluated using an isokinetic dynamometer. The results showed that photobiomodulation was able of reducing muscle fatigue by a significant increase of electromyographic fatigue index (EFI) (p = 0.047) and decreasing significantly lactate concentration 6 min after the performance of the fatigue protocol (p = 0. 0006) compared the placebo laser session. However, the photobiomodulation was not able of increasing muscle performance measured by the isokinetic dynamometer. Thus, it can be conclude that the photobiomodulation was effective in reducing fatigue levels. However, no effects of photobiomodulation on muscle performance was observed.

  15. BMD in elite female triathletes is related to isokinetic peak torque without any association to sex hormone concentrations

    DEFF Research Database (Denmark)

    Helge, Eva Wulff; Melin, Anna; Waaddegaard, Mette

    2012-01-01

    Female endurance athletes suffering from low energy availability and reproductive hormonal disorders are at risk of low BMD. Muscle forces acting on bone may have a reverse site-specific effect. Therefore we wanted to test how BMD in female elite triathletes was associated to isokinetic peak torque...... (IPT) and reproductive hormone concentrations (RHC). A possible effect of oral contraceptives (OCON's) is taken into consideration....

  16. Isokinetic eccentric resistance training prevents loss in mechanical muscle function after running

    DEFF Research Database (Denmark)

    Oliveira, Anderson S. C.; Caputo, Fabrizio; Aagaard, Per

    2013-01-01

    session, subjects performed treadmill running (~35 min) and the previously mentioned measurements were repeated immediately after running. Subsequently, subjects were randomized to training (n = 12) consisting of 24 sessions of maximal IERT knee extensors actions at 180° s(-1), or served as controls (n...... damages. However, IERT may not avoid reductions in explosive muscle actions. In turn, this may allow more intense training sessions to be performed, facilitating the adaptive response to running training.......The aim of the study was to verify whether 8 weeks of resistance training employing maximal isokinetic eccentric (IERT) knee extensor actions would reduce the acute force loss observed after high-intensity treadmill running exercise. It was hypothesized that specific IERT would induce protective...

  17. Age, weight, and the front abdominal power test as predictors of isokinetic trunk strength and work in young men and women.

    Science.gov (United States)

    Cowley, Patrick M; Fitzgerald, Sharon; Sottung, Kyle; Swensen, Thomas

    2009-05-01

    First we tested the reliability of two new field tests of core stability (plank to fatigue test [PFT] and front abdominal power test [FAPT]), as well as established measures of core stability (isokinetic trunk extension and flexion strength [TES and TFS] and work [TEW and TFW]) over 3 days in 8 young men and women (24.0 +/- 3.1 years). The TES, TFS, TFW, and FAPT were highly reliable, TEW was moderately reliable, and PFT were unreliable for use during a single testing session. Next, we determined if age, weight, and the data from the reliable field test (FAPT) were predictive of TES, TEW, TFS, and TFW in 50 young men and women (19.0 +/- 1.2 years). The FAPT was the only significant predictor of TES and TEW in young women, explaining 16 and 15% of the variance in trunk performance, respectively. Weight was the only significant predictor of TFS and TFW in young women, explaining 28 and 14% of the variance in trunk performance, respectively. In young men, weight was the only significant predictor of TES, TEW, TFS, and TFW, and explained 27, 35, 42, and 33%, respectively, of the variance in trunk performance. In conclusion, the ability of weight and the FAPT to predict TES, TEW, TFS, and TFW was more frequent in young men than women. Additionally, because the FAPT requires few pieces of equipment, is fast to administer, and predicts isokinetic TES and TEW in young women, it can be used to provide a field-based estimate of isokinetic TES and TEW in women without history of back or lower-extremity injury.

  18. Haptic control of a pneumatic muscle actuator to provide resistance for simulated isokinetic exercise; part II: control development and testing.

    Science.gov (United States)

    Hall, Kara L; Phillips, Chandler A; Reynolds, David B; Mohler, Stanley R; Rogers, Dana B; Neidhard-Doll, Amy T

    2015-01-01

    Pneumatic muscle actuators (PMAs) have a high power to weight ratio and possess unique characteristics which make them ideal actuators for applications involving human interaction. PMAs are difficult to control due to nonlinear dynamics, presenting challenges in system implementation. Despite these challenges, PMAs have great potential as a source of resistance for strength training and rehabilitation. The objective of this work was to control a PMA for use in isokinetic exercise, potentially benefiting anyone in need of optimal strength training through a joint's range of motion. The controller, based on an inverse three-element phenomenological model and adaptive nonlinear control, allows the system to operate as a type of haptic device. A human quadriceps dynamic simulator was developed (as described in Part I of this work) so that control effectiveness and accommodation could be tested prior to human implementation. Tracking error results indicate that the control system is effective at producing PMA displacement and resistance necessary for a scaled, simulated neuromuscular actuator to maintain low-velocity isokinetic movement during simulated concentric and eccentric knee extension.

  19. The effect of peculiar complex core balance training on isokinetic muscle functions of the knee and lumbus

    OpenAIRE

    Lee, Myungsun; Han, Gunsoo

    2016-01-01

    [Purpose] This study aimed to investigate the effect of peculiar complex core balance training on the isokinetic muscle function of the knee joint and lumbus to provide fundamental data for establishing a training program that focuses on improving the performance and prevention of injury by developing the core and low extremity muscles. [Subjects and Methods] The participants in this study included a total of ten high school athletes involved in a throwing event for over five years. The subje...

  20. A method to reduce the number of measured parameters when using isokinetic muscle strength as a clinical indicator in rheumatoid arthritis patients

    DEFF Research Database (Denmark)

    Schiøttz-Christensen, Berit; Theil Skovgaard, Lene; Danneskiold-Samsøe, B

    2001-01-01

    The aim of the study was to present a method enabling a reduction of the number of measurements when quantifying isokinetic muscle strength (IMS), and to describe an expression for IMS which is independent of measuring conditions. IMS is a measure of muscle strength used to categorise patients...

  1. ACL deficient potential copers and non-copers reveal different isokinetic quadriceps strength profiles in the early stage after injury

    Science.gov (United States)

    Eitzen, I; Eitzen, TJ; Holm, I; Snyder-Mackler, L; Risberg, MA

    2011-01-01

    Background Isokinetic muscle strength tests using the peak torque value is the most frequently included quadriceps muscle strength measurement for anterior cruciate ligament (ACL) injured subjects. Aims The purpose of this study was to investigate quadriceps muscle performance during the whole isokinetic curve in ACL deficient subjects classified as potential copers or non-copers, and investigate whether these curve profiles were associated with single-leg hop performance. We hypothesized that quadriceps muscle torque at other knee flexion angles than peak torque would give more information about quadriceps muscle strength deficits. Furthermore, we hypothesized that there would be significant torque differences between potential copers and non-copers, and a significant relationship between angle specific torque values and single-leg hop performance. Study Design Cross-sectional study; Level of evidence, 2 Methods Seventy-six individuals with a complete unilateral ACL rupture within the last 3 months were included. The subjects were classified into potential copers and non-copers according to the criteria from Fitzgerald et al12. Isokinetic quadriceps muscle tests were performed at 60°/sec (Biodex 6000). Mean torque values were calculated for peak torque as well as for specific knee flexion angles. The one-leg hop and the 6 meter timed hop tests were included and symmetry indices were used. Results The peak torque value did not identify the largest quadriceps muscle strength deficit. Rather, these were established at knee flexion angles of less than 40°. There were significant differences in angle specific torque values between potential copers and non-copers (p<0.05). Moderate to strong associations were disclosed between angle specific torque values and single-leg hop performance, but only for non-copers (r≥0.32– 0.58). Conclusions Angle specific quadriceps muscle torque values of less than 40° of knee flexion provide more information on the quadriceps

  2. Avaliação isocinética no joelho do atleta Isokinetic evaluation of athletes' knee

    Directory of Open Access Journals (Sweden)

    Antonio Sérgio A.P. Terreri

    2001-10-01

    Full Text Available A avaliação isocinética tem sido usada nas últimas três décadas como método para se determinar o padrão funcional da força e do equilíbrio muscular. No nosso meio cresceu nos últimos 10 anos. É possível quantificar valores absolutos do torque, do trabalho e da potência de grupos musculares, bem como valores relativos, ou seja, da proporção agonista/antagonista de tais grupos. Outro recurso valioso consiste como método auxiliar na reabilitação das lesões esportivas. O exame é realizado com velocidade angular constante e predeterminada, seja lenta, intermediária e/ou rápida. O joelho é a articulação em que se observa maior aplicação e estudos isocinéticos. Na prática esportiva, temos por um lado a importância da proporção do equilíbrio muscular agonista/antagonista, ou seja, do equilíbrio flexor/extensor representado, respectivamente, pelos isquiotibiais/quadríceps. De outro, a comparação dos valores absolutos da função muscular entre os lados direito e esquerdo, quer seja para o quadríceps, ou para os isquiotibiais. Resultados alterados estão relacionados, geralmente, às lesões esportivas ou suas seqüelas. De interesse para o atleta e para a equipe multidisciplinar é poder dispor de um método de avaliação funcional muscular objetivo e seguro, que forneça dados confiáveis e reprodutíveis. Aspecto relevante reside no fato do resultado do teste isocinético poder ser útil nos critérios de retorno a atividade esportiva pós-lesão. Este artigo de revisão consiste em abordar alguns aspectos práticos da avaliação isocinética no joelho e sua utilização para os indivíduos que realizam atividade física.The isokinetic evaluation has been used in the last three decades as a method to determine both the strength functional pattern and the muscle balance. In our environment, this evaluation has been spread over the last 10 years. It is possible to quantify absolute values of torque, effort, and

  3. Isokinetic strength and endurance after percutaneous and open surgical repair of Achilles tendon ruptures.

    Science.gov (United States)

    Goren, David; Ayalon, Moshe; Nyska, Meir

    2005-04-01

    Reports on complete spontaneous Achilles tendon ruptures and associated treatment have become more frequent in the literature in the past two decades, as has the request for treatments that enable the finest possible functional recovery. The best available treatment is a matter of considerable controversy in the literature. The purpose of this study was to compare the isokinetic strength and endurance of the plantarflexor muscle-tendon unit in subjects who sustained rupture of the Achilles tendon and underwent either open surgery or closed percutaneous repair of the Achilles tendon. Twenty patients (18 males, 2 females) with spontaneous ruptures of the Achilles tendon were included in this study. Ten patients were treated by open surgery, and 10 patients were treated percutaneously. All patients had ruptured their Achilles tendon more than 6 months before the study, and all of the ruptures occurred 3.5 years or less before the day of the testing. All patients underwent an oriented physical examination. An isokinetic Biodex dynamometer (Biodex Medical System, Shirley, NY) was used to measure ankle joint angle, and in plantarflexion to calculate the torque at the ankle joint (Newton/meter), and the average work (jouls) for both maximal power and endurance. Each measurement was compared to the normal ankle. Biodex dynamometer evaluations at 90 deg/sec demonstrated a significant difference of maximal voluntary plantarflexor torque, endurance performance and range of motion at the ankle joint between the involved and uninvolved sides in patients treated by either mode of treatment. Yet, no statistically significant differences were revealed for the parameters mentioned above between the subjects that were treated either percutaneously or by an open surgery. In functional terms, the biomechanical outcomes of open surgery and percutaneous repair for acute ruptures of the Achilles tendon are both effective.

  4. Relation of 25-meter Swimming Performance with Physical Properties and Isokinetic Knee Strength in Amateur Young Swimmers

    OpenAIRE

    DOKUMACI, Bircan; AYGÜN, Cihan; ÇAKIR ATABEK, Hayriye

    2017-01-01

    The purpose of this study was to investigate the relationship between physical properties,isokinetic knee strength and swimming performance in young amateur athletes. Seventeen 18-24 year old amateur swimmers (n=13 males, mean age=20.0 ± 2.1 years; n=4 females, meanage=21.5 ± 1.7 years) volunteered to participate in this study. All athletes were member of thesame team who were engaged to the swim training at least for 4 years. Following the 5-minwarm up session, each participant performed thr...

  5. The Effect of Eight Weeks Plyometric Training on Anaerobic Power, Counter Movement Jumping and Isokinetic Strength in 15-18 Years Basketball Players

    Science.gov (United States)

    Adigüzel, Niyazi Sidki; Günay, Mehmet

    2016-01-01

    The purpose of this study was to investigate the effect of eight weeks plyometric training on anaerobic power, counter movement jumping and isokinetic strength in 15-18 years aged basketball players. This study was including 30 male Basketball players. The subjects were divided into two groups as: the experimental group (n = 15) and the control…

  6. Effects of fatiguing isometric and isokinetic ankle exercises on postural control while standing on firm and compliant surfaces.

    Science.gov (United States)

    Bisson, Etienne J; Remaud, Anthony; Boyas, Sébastien; Lajoie, Yves; Bilodeau, Martin

    2012-06-14

    Fatiguing exercises used across studies to induce alterations in postural control are diverse and may explain the different findings reported. This study aimed to compare the effects of two types of fatiguing plantarflexion exercises on postural control on a firm and a compliant surface. Ten healthy young men (29 ± 4 years) were asked to stand as steadily as possible for 30 s, blindfolded with feet together, on a firm and a compliant surface before and immediately after an isometric and an isokinetic fatiguing exercise. Maximal force reduction due to fatigue was found significant but similar between exercises. No significant difference was found between the fatiguing exercises on all Center of Pressure (CoP) parameters. Both fatiguing exercises induced increases in CoP excursion area, CoP variability and CoP velocity in both planes (antero-posterior, mediolateral) on the compliant surface. On the firm surface, both fatiguing exercises only induced increases in CoP variability and CoP velocity in the fatigued plane (antero-posterior). Isometric and isokinetic fatiguing exercises, when producing a similar level of force reduction, induce similar decreases in postural control. The effects of fatigue on postural control in healthy young men are more pronounced when standing on a compliant surface, i.e. when proprioceptive information at the ankle is altered.

  7. The association of trunk muscle cross-sectional area and magnetic resonance image parameters with isokinetic and psychophysical lifting strength and static back muscle endurance in men.

    Science.gov (United States)

    Gibbons, L E; Latikka, P; Videman, T; Manninen, H; Battié, M C

    1997-10-01

    The relationship between trunk muscle morphology as measured on transverse magnetic resonance images and isokinetic lifting, psychophysical lifting, and static back muscle endurance testing was examined in 110 men, ages 35-67 years (mean, 48 years), who had been chosen based on their exposure to a wide variety of occupational and leisure-time physical activities. The computed T2-relaxation times and the T2-weighted and proton density-weighted signal intensities of the erector spinae, quadratus lumborum, and psoas major muscles had almost no association with any of the strength tests. The cross-sectional areas of the muscles had good correlations with isokinetic lifting strength (r = 0.46-0.53). They did not correlate well with psychophysical lifting and static back muscle endurance. Other characteristics or neurological or psychological factors may have more influence on those tests.

  8. Gender Differences in Isokinetic Strength after 60 and 90 d Bed Rest

    Science.gov (United States)

    English, K. L.; Ploutz-Snyder, R. J.; Cromwell, R. L.; Ploutz-Snyder, L. L.

    2010-01-01

    Recent reports suggest that changes in muscle strength following disuse may differ between males and females. PURPOSE: To examine potential gender differences in strength changes following 60 and 90 d of experimental bed rest. METHODS: Isokinetic extensor and flexor strength of the knee (60deg and 180deg/s, concentric only), ankle (30deg/s, concentric and eccentric), and trunk (60deg/s, concentric only) were measured following 60 d (males: n=4, 34.5+/-9.6 y; females: n=4, 35.5+/-8.2 y) and 90 d (males: n=10, 31.4+/-4.8 y; females: n=5, 37.6+/-9.9 y) of 6-degree head-down-tilt bed rest (BR; N=23). Subjects were fed a controlled diet (55%/15%/ 30%, CHO/PRO/FAT) that maintained body weight within 3% of the weight recorded on Day 3 of bed rest. After a familiarization session, testing was conducted 6 d before BR and 2 d after BR completion. Peak torque and total work were calculated for the tests performed. To allow us to combine data from both 60- and 90-d subjects, we used a mixed-model statistical analysis in which time and gender were fixed effects and bed rest duration was a random effect. Log-transformations of strength measures were utilized when necessary in order to meet statistical assumptions. RESULTS: Main effects were seen for both time and gender (p<0.05), showing decreased strength in response to bed rest for both males and females, and males stronger than females for most strength measures. Only one interaction effect was observed: females exhibited a greater loss of trunk extensor peak torque at 60 d versus pre-BR, relative to males (p=0.004). CONCLUSION: Sixty and 90 d of BR induced significant losses in isokinetic muscle strength of the locomotor and postural muscles of the knee, ankle, and trunk. Although males were stronger than females for most of the strength measures that we examined, only changes in trunk extensor peak torque were greater for females than males at day 60 of bed rest

  9. Seasonal variation in isokinetic strength of knee flexors and extensors in soccer players

    Directory of Open Access Journals (Sweden)

    Michal Lehnert

    2015-06-01

    Full Text Available BACKGROUND: Muscle strength is an important factor in soccer from the performance and health perspective. There is a lack of knowledge about changes in muscle strength of the knee flexors and extensors and their ratios during annual training cycle. OBJECTIVES: The aim of this study was to evaluate the seasonal variability of the observed parameters of isokinetic strength of the knee flexors and extensors in soccer players, U19, from the performance and health perspective. METHODS: The strength of the knee flexors and extensors was measured in players U19 category (n = 9; the average age 18.5 ±0.4 years on the isokinetic dynamometer IsoMed 2000 in angular velocity 60° × s-1. Measurement was performed in concentric/concentric and excentric/excentric mode of muscle action at the beginning of the winter preparatory period, at the end of the preparatory period and at the end of the spring competitive period. Monitored parameters were absolute peak torque (PT, conventional H/Q ratio (H/QCON, functional H/Q ratio (H/QFUN and functional H/Q ratio in range 10-30° of knee flexion (H/QFUN_10-30. RESULTS: Significant change in PT (p < .05 was noted only in cases of the knee extensors of the nondominant leg in the concentric mode. The evaluation of imbalance of the knee flexors and extensors by H/QCON and H/QFUN ratios did not show any significant changes, but there was found a significant decrease of the H/QFUN_10-30 ratio in the dominant leg between measurements at the beginning and at the end of the winter preparatory period. CONCLUSIONS: The results of the current study indicate that throughout the monitored periods of the annual training cycle desirable changes in knee flexors and extensors strength did not occur. The values suggest the disruption of the dynamic stabilization of the knee joint and increase in injury risk. Different dynamics of the three observed ratios confirmed that they provide different information about the physical fitness of

  10. Comparison of whole-body vibration exercise and plyometric exercise to improve isokinetic muscular strength, jumping performance and balance of female volleyball players

    OpenAIRE

    Kim, Yong-Youn; Park, Si-Eun

    2016-01-01

    [Purpose] The purpose of this study was to assess the effect of whole-body vibration exercise and plyometric exercise on female volleyball players. [Subjects and Methods] Subjects were randomly allocated to two exercise groups (whole-body vibration exercise group and plyometric exercise group). The exercise was conducted three times each week for 8 weeks. Isokinetic muscular strength, jumping performance, and balance were measured before starting the exercise and after finishing the 8 weeks o...

  11. Effects of humeral head compression taping on the isokinetic strength of the shoulder external rotator muscle in patients with rotator cuff tendinitis

    OpenAIRE

    Kim, Moon-Hwan; Oh, Jae-Seop

    2015-01-01

    [Purpose] The purpose of this study was to examine the effects of humeral head compression taping (HHCT) on the strength of the shoulder external rotator muscle in patients with rotator cuff tendinitis. [Subjects and Methods] Twenty patients with rotator cuff tendinitis were recruited. The shoulder external rotator strength was measured using a Biodex isokinetic dynamometer system. A paired t-test was performed to evaluate within-group differences in the strength of the shoulder external rota...

  12. Isokinetic force of under-twenties soccer players: comparison of players in different field positions

    Directory of Open Access Journals (Sweden)

    Raphael Mendes Ritti Dias

    2007-06-01

    Full Text Available During a soccer match, countless movements involving muscular force are performed. While some studies have analyzed the force exerted by soccer players, their results have been divergent, particularly when force has been analyzed with respect to fi eld positions. The objective of this study was to compare peak torque, total muscular work, maximum power and isokinetic fatigue index of the knee fl exor and extensor muscles of soccer players in a variety of fi eld positions. Seventy-eight under-twenty soccer players were classifi ed according to the position they play: goalkeepers (n=7, full backs (n=14, wingers (n=16, defensive midfi elders (n=11, center midfi elders (n=14 and forwards (n=16. The concentric isokinetic force of knee fl exor and extensor muscles was evaluated using an isokinetic dynamometer, Cybex® brand Norm™ 6000 model (CSMI, USA. Data was analyzed in terms of non-parametric statistics and results expressed in medians and semi-interquartile range. The Kruskal-Wallis test was applied and when results were signifi cant to pRESUMO Durante uma partida de futebol são realizados inúmeros movimentos que envolvem a força muscular. Embora alguns estudos tenham analisado a força de jogadores de futebol, os resultados encontrados têm sido controversos, principalmente quando analisada a força em função da posição de jogo. O objetivo deste estudo foi comparar o pico de torque, trabalho muscular total, potência máxima e índice de fadiga isocinético dos músculos fl exores e extensores de joelho de jogadores de futebol que atuam em diferentes posições de jogo. Foram incluídos 78 atletas de futebol, pertencentes à categoria Sub-20, foram agrupados de acordo com a posição em campo de jogo: goleiros (n=7, zagueiros (n=14, laterais (n=16, volantes (n=11, meio campo (n=14 e atacantes (n=16. Foi realizada avaliação da força isocinética concêntrica dos músculos fl exores e extensores de joelho em dinamômetro isocin

  13. ISOKINETIC COMPARISON OF THE ROTATOR CUFF BETWEEN WATERPOLO AND TENNIS PLAYERS/ COMPARAREA ISOKINETICĂ A COIFULUI ROTATORILOR ÎNTRE JUCĂTORII DE POLLO ŞI CEI DE TENIS

    Directory of Open Access Journals (Sweden)

    Linde FJ

    Full Text Available Isokinetic evaluation is an objective method that allows rapid and reliable comparison of the relationship between the muscle groups of the rotator cuff, during dynamic exercise. At shoulder level, balance between the rotator cuff muscle groups is essential for keeping joint stability. The purpose of this study is to detect significant differences in muscular performance strength values of the muscles of the rotator cuff by isokinetic tests, in two overhead sport specialities: water polo and tennis. Comparison could be realized analyzing various parameters derivate of the test. Material and methods. We undertook an isokinetic study in a group of 36 high-level athletes: 30 water polo players (12 women and 18 men and 6 tennis players (2 women and 4 men. The parameters analyzed were: peak torque (PT, maximal repetition work (MRW, muscle asymmetry between dominant and no dominant shoulder, and ratio between external and internal rotators. Results. For all tested values of PT, the dominant limb has always been stronger than the no dominant in both sports, but differences in tennis players were much higher in favor of the dominant than water polo players with specific reference to IR. With regard to MRW, water polo players had values higher than tennis players in ER of both sides, but the IR of the dominant limb is greater in tennis players. Conclusions. In water polo players, due to the environment in which specific work is developed and the symmetrical content of simming, the ratios in both extremities were very symmetrical (related to PT; in tennis players, the dominant limb had more normal ratio values but this doesn’t happen in the no dominant possibly because it comes into play shortly.

  14. Adaptation of the DP 50 dust meter for measuring dust content under isokinetic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vitek, J.; Novak, L.

    1985-03-01

    The DP 50 dust meter, developed by the Scientific Coal Research Institute Ostrava-Radvanice, is used for measuring dust content in the air in underground coal mines. Two versions of the system are used: a type developed in 1970 which is placed in a vertical position and used to measure the content of respirable coal particles in the air; and a type developed in 1983 for isokinetic measurement of dust content in the air. The latter is equipped with 8 cone-shaped adapters (with differing size and dimensions of the cone inlet adjusted to air flow rates from 0.25 to 8.00 m/s). Specifications of the 8 adapters are given in a table. The 1983 version of the DP 50 is placed in a horizontal position with the dust meter axis parallel to the direction of air flow ventilating a mine working. Recommendations for installation of dust meters in underground workings and effects of installation on measurement accuracy are discussed. 16 references.

  15. A Ground-Based Comparison of the Muscle Atrophy Research and Exercise System (MARES) and a Standard Isokinetic Dynamometer

    Science.gov (United States)

    Hackney, K. J.; English, K. L.; Redd, E.; DeWitt, J. K.; Ploutz-Snyder, R.; Ploutz-Snyder, L. L.

    2010-01-01

    PURPOSE: 1) To compare the test-to-test reliability of Muscle Atrophy Research and Exercise System (MARES) with a standard laboratory isokinetic dynamometer (ISOK DYN) and; 2) to determine if measures of peak torque and total work differ between devices. METHODS: Ten subjects (6M, 4F) completed two trials on both MARES and an ISOK DYN in a counterbalanced order. Peak torque values at 60 deg & 180 deg / s were obtained from five maximal repetitions of knee extension (KE) and knee flexion (KF). Total work at 180 deg / s was determined from the area under the torque vs. displacement curve during twenty maximal repetitions of KE and KF. Reliability of measures within devices was interpreted from the intraclass correlation coefficient (ICC) and compared between devices using the ratio of the within-device standard deviations. Indicators of agreement for the two devices were evaluated from: 1) a calculation of concordance (rho) and; 2) the correlation between the mean of measures versus the delta difference between measures (m u vs delta). RESULTS: For all outcome measures ICCs were high for both the ISOK DYN (0.95-0.99) and MARES (0.90-0.99). However, ratios of the within-device standard deviation were 1.3 to 4.3 times higher on MARES. On average, a wide range (3.3 to 1054 Nm) of differences existed between the values obtained. Only KE peak torque measured at 60 deg & 180 deg / s showed similarities between devices (rho = 0.91 & 0.87; Pearson's r for m u vs delta = -0.22 & -0.37, respectively). CONCLUSION: Although MARES was designed for use in microgravity it was quite reliable during ground-based testing. However, MARES was consistently more variable than an ISOK DYN. Future longitudinal studies evaluating a change in isokinetic peak torque or total work should be limited within one device.

  16. Efeitos de diferentes intervalos de recuperação no desempenho muscular isocinético em idosos Effects of different rest intervals on isokinetic muscle performance among older adults

    Directory of Open Access Journals (Sweden)

    C Ernesto

    2009-02-01

    Full Text Available OBJETIVO: Comparar os efeitos de diferentes intervalos de recuperação (IR entre séries de contração isocinética no desempenho muscular em idosos. MÉTODOS: Vinte idosos voluntários (66,9±3,9 anos, 76,1±13,4kg, 169±5,2cm foram submetidos a três sessões de exercício resistido isocinético unilateral da musculatura extensora do joelho com diferentes IR (1 minuto, 2 minutos, e 3 minutos na velocidade de 60°•s-1. Cada sessão consistia em três séries de 10 repetições durante as quais foram avaliados o pico de torque (PT, trabalho total (TT e índice de fadiga (IF. ANOVA fatorial para medidas repetidas, com a análise de Post hoc por Bonferroni, foi utilizada para identificar possíveis diferenças entre os IR. O nível de significância estatístico utilizado foi de p0,05. Apesar de ter sido observado menor desempenho muscular na 3ª série em todos os IR, maiores quedas no PT, TT e IF foram observadas quando adotado o IR de 1minuto (pOBJECTIVE: To compare the effects of different rest intervals (RI between sets of isokinetic contractions on muscle performance in older adults. METHODS: Twenty older participants (66.9±3.9 years; 76.1±13.4kg; 169±5.2cm underwent three sessions of unilateral isokinetic training for the knee extensor muscles, with different RI (1 minute, 2 minutes and 3 minutes at an angular velocity of 60°•s-1. Each session consisted of three sets of 10 repetitions, during which the peak torque (PT, total work (TW and fatigue index (FI were evaluated. Factorial ANOVA for repeated measurements, with Bonferroni post-hoc analysis, was used to identify possible differences between the RI. The statistical significance level was set at p0.05. Although muscle performance was lower during the third sets with all RI, the greatest decreases in PT, TW and FI occurred with the 1 minute RI (p<0.05. CONCLUSIONS: The results showed that the RI variable has an important influence on isokinetic muscle performance in older

  17. Muscle Strength and Poststroke Hemiplegia

    DEFF Research Database (Denmark)

    Kristensen, Otto H; Stenager, Egon; Dalgas, Ulrik

    2017-01-01

    undergone peer review; and (4) were available in English or Danish. DATA EXTRACTION: The psychometric properties of isokinetic dynamometry were reviewed with respect to reliability, validity, and responsiveness. Furthermore, comparisons of strength between paretic, nonparetic, and comparable healthy muscles...... isokinetic dynamometry. DATA SOURCES: A systematic literature search of 7 databases was performed. STUDY SELECTION: Included studies (1) enrolled participants with definite poststroke hemiplegia according to defined criteria; (2) assessed muscle strength or power by criterion isokinetic dynamometry; (3) had...... were reviewed. DATA SYNTHESIS: Twenty studies covering 316 PPSH were included. High intraclass correlation coefficient (ICC) inter- and intrasession reliability was reported for isokinetic dynamometry, which was independent of the tested muscle group, contraction mode, and contraction velocity...

  18. The Relationship between Isokinetic Relative Torque of Hip, Knee and Ankle Joints and the Height of Guide Leg Jump in Young Men

    Directory of Open Access Journals (Sweden)

    Saeed Nikoukheslat

    2016-06-01

    Full Text Available Objective: The aim of this study was to investigate the relationship between isokinetic relative torques of hip, knee and ankle joints and the height of guide leg jump in young men. Methods: 27 college male athletes with mean age of 25±3.5 years, height 178.5±7.8 cm and weight of 75.7±10.7 kg voluntarily participated in this study. Isokinetic torque of hip, knee and ankle joints and the height of vertical jump were measured using BIODEX SYSTEM PRO 4 and digital vertical jumping tester systems respectively. Pearson correlation test at p<0.05 was used for statistical analysis. Results: Results showed that there were significant correlations between height of jump and hip joint flexion (p= 0.047 & r= 0.39 and extension (p= 0.003 & r= 0.55 torques of guide leg, hip joint extension torque of support leg (p= 0.020 & r=0.45 and knee joint flexion (p= 0.019 & r=0.45 and extension torques of support leg (p=0.006 & r=0.52. Conclusion: The results of this study show that flexion and extension torques of hip joint in guide leg and knee joint in support leg and also extension torque of hip joint in support leg have main effect on height of guide leg jump. Thus, in designing a specific training program for athletes in whom the nature of jump in their sports is guide leg jump, particular attention should be given to hip and knee joints strength.

  19. Isokinetic dynamometry of knee flexors and extensors: comparative study among non-athletes, jumper athletes and runner athletes

    Directory of Open Access Journals (Sweden)

    Siqueira Cássio Marinho

    2002-01-01

    Full Text Available Participation in intensive sports activities leads to muscular specializations that may generate alterations in involved articular forces and cause static (posture and dynamic changes (alterations of articular stability, coordination, etc.. Prevention of injury requires specific functional muscular evaluation in all athletes and for any kind of sport. OBJECTIVE: To dynamically evaluate, through isokinetic tests, the peak torque, total work, and average power of the knee flexor and extensor muscles of jumper and runner athletes and compare them to those of a non-athletic population, evaluating dominance and balance between agonistic and antagonistic muscle groups. RESULTS: In the non-athlete group, we noted a higher asymmetry between the dominant and nondominant members. The jumpers had the highest values of the evaluated parameters of all groups, whereas parameters for the runners were intermediate between non-athletes and jumpers.

  20. Effect of contraction mode of slow-speed resistance training on the maximum rate of force development in the human quadriceps

    DEFF Research Database (Denmark)

    Blazevich, Anthony J; Horne, Sara; Cannavan, Dale

    2008-01-01

    This study examined the effects of slow-speed resistance training involving concentric (CON, n = 10) versus eccentric (ECC, n = 11) single-joint muscle contractions on contractile rate of force development (RFD) and neuromuscular activity (EMG), and its maintenance through detraining. Isokinetic...

  1. Isokinetic profile of elbow flexion and extension strength in elite junior tennis players.

    Science.gov (United States)

    Ellenbecker, Todd S; Roetert, E Paul

    2003-02-01

    Descriptive study. To determine whether bilateral differences exist in concentric elbow flexion and extension strength in elite junior tennis players. The repetitive nature of tennis frequently produces upper extremity overuse injuries. Prior research has identified tennis-specific strength adaptation in the dominant shoulder and distal upper extremity musculature of elite players. No previous study has addressed elbow flexion and extension strength. Thirty-eight elite junior tennis players were bilaterally tested for concentric elbow flexion and extension muscle performance on a Cybex 6000 isokinetic dynamometer at 90 degrees/s, 210 degrees/s, and 300 degrees/s. Repeated-measures ANOVAs were used to test for differences between extremities, muscle groups, and speed. Significantly greater (Pelbow extension peak torque values were measured at 90 degrees/s, 210 degrees/s, and 300 degrees/s for males. Significantly greater (Pelbow flexion muscular performance in males and for elbow flexion or extension peak torque and single-repetition work values in females. No significant difference between extremities was measured in elbow flexion/extension strength ratios in females and significant differences between extremities in this ratio were only present at 210 degrees/s in males (Pelbow in male elite junior tennis players but not females. These data have ramifications for clinicians rehabilitating upper extremity injuries in patients from this population.

  2. Effects of humeral head compression taping on the isokinetic strength of the shoulder external rotator muscle in patients with rotator cuff tendinitis.

    Science.gov (United States)

    Kim, Moon-Hwan; Oh, Jae-Seop

    2015-01-01

    [Purpose] The purpose of this study was to examine the effects of humeral head compression taping (HHCT) on the strength of the shoulder external rotator muscle in patients with rotator cuff tendinitis. [Subjects and Methods] Twenty patients with rotator cuff tendinitis were recruited. The shoulder external rotator strength was measured using a Biodex isokinetic dynamometer system. A paired t-test was performed to evaluate within-group differences in the strength of the shoulder external rotator muscle. [Results] Significantly higher shoulder external rotator peak torque and peak torque per body weight were found in the HHCT condition than in the no-taping condition. [Conclusion] HHCT may effectively increase the shoulder external rotator muscle strength in patients with rotator cuff tendinitis.

  3. Shoulder rotator isokinetic strength profile in young swimmers. DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n5p545

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    Pablo Tomas-Carus

    2012-09-01

    Full Text Available Considering that some studies suggest that shoulder rotators muscle imbal­ances are related to joint pain and injury, and that there are no normative data for young swimmers, the aim of this study was: i to describe the muscle balance, fatigue and isokinetic strength profile of the shoulder rotators in young swimmers; ii to compare the results between swimmers and a group of young non-practitioners; iii to contribute to the acquisition of normative data of unilateral ratios of shoulder rotators. We evaluated the shoulder rotators concentric strength and unilateral ratios (ratio between torque of external and internal rotators of 60 swimmers (age: 14.55 ± 0.5 years old; body mass: 61.16 ± 7.08 kg and 60 non-practitioners (age: 14.62 ± 0.49 years old; body mass: 60.22 ± 10.01 kg. The evaluation was performed in the sitting position (90° abduction and elbow flexion at 60º.s-1 and 180º.s-1 angular speeds using an isokinetic dynamometer (Biodex System 3. The results of the fatigue ratios revealed no differences between the groups. Swimmers showed unilateral ratios of 73.39 ± 17.26% in the dominant limb (DL and 77.89 ± 15,23% in the non-dominant limb (NDL for assessments at 60º.s-1. At 180º.s-1, ratios were 74.77± 13.99% for DL and 70.11 ± 14.57% for NDL. Swimmers presented greater muscle imbalance, and differed from non-practitioners in the ability to produce power with the internal rotators, which was significantly higher in the former group.

  4. Anthropometric, biomechanical, and isokinetic strength predictors of ball release speed in high-performance cricket fast bowlers.

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    Wormgoor, Shohn; Harden, Lois; Mckinon, Warrick

    2010-07-01

    Fast bowling is fundamental to all forms of cricket. The purpose of this study was to identify parameters that contribute to high ball release speeds in cricket fast bowlers. We assessed anthropometric dimensions, concentric and eccentric isokinetic strength of selected knee and shoulder muscle groups, and specific aspects of technique from a single delivery in 28 high-performance fast bowlers (age 22.0 +/- 3.0 years, ball release speed 34.0 +/- 1.3 m s(-1)). Six 50-Hz cameras and the Ariel Performance Analysis System software were used to analyse the fast and accurate deliveries. Using Pearson's correlation, parameters that showed significant associations with ball release speed were identified. The findings suggest that greater front leg knee extension at ball release (r=0.52), shoulder alignment in the transverse plane rotated further away from the batsman at front foot strike (r=0.47), greater ankle height during the delivery stride (r=0.44), and greater shoulder extension strength (r=0.39) contribute significantly to higher ball release speeds. Predictor variables failed to allow their incorporation into a multivariate model, which is known to exist in less accomplished bowlers, suggesting that factors that determine ball release speed found in other groups may not apply to high-performance fast bowlers.

  5. The effect of a 6-week land and resistance training of 13-16 years old swimmers groups to lower limb isokinetic strength values and to swimming performance13-16 yaş grubu yüzücülerde 6 haftalık kara ve direnç antrenmanlarının alt ekstremite izokinetik kuvvet performansına ve yüzme derecelerine etkisi

    OpenAIRE

    Yapıcı, Ayşegül; Maden, Barış; Fındıkoğlu, Gülin

    2016-01-01

    The aim of this study is to investigate the effect of a 6-week land and resistance training of 13-16 year old swimmers groups to lower limb isokinetic strength values and to swimming performance. 22 swimmers participated in this study. The subjects were divided into three groups (A-B-C) according to their 50m swimming degrees. 25m underwater,25m,50m,75m and 100m freestyle swimming degrees of swimmers were recorded. As isokinetic measurements was applied at 60°/s,180°/s and 240°/s speed and th...

  6. Isokinetic imbalance of adductor-abductor hip muscles in professional soccer players with chronic adductor-related groin pain.

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    Belhaj, K; Meftah, S; Mahir, L; Lmidmani, F; Elfatimi, A

    2016-11-01

    This study aims to compare the isokinetic profile of hip abductor and adductor muscle groups between soccer players suffering from chronic adductor-related groin pain (ARGP), soccer players without ARGP and healthy volunteers from general population. Study included 36 male professional soccer players, who were randomly selected and followed-up over two years. Of the 21 soccer players eligible to participate in the study, 9 players went on to develop chronic ARGP and 12 players did not. Ten healthy male volunteers were randomly selected from the general population as a control group. Comparison between the abductor and adductor muscle peak torques for players with and without chronic ARGP found a statistically significant difference on the dominant and non-dominant sides (p muscle significantly stronger than the adductor muscle. In the group of healthy volunteers, the adductor muscle groups were significantly stronger than the abductor muscle groups on both dominant and non-dominant sides (p muscle strength was also significantly decreased on the affected side. This imbalance appears to be a risk factor for adductor-related groin injury. Therefore, restoring the correct relationship between these two agonist and antagonist hip muscles may be an important preventative measure that should be a primary concern of training and rehabilitation programmes.

  7. Haptic control of a pneumatic muscle actuator to provide resistance for simulated isokinetic exercise: Part I--dynamic test station and human quadriceps dynamic simulator.

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    Hall, Kara L; Phillips, Chandler A; Reynolds, David B; Mohler, Stanley R; Rogers, Dana B; Neidhard-Doll, Amy T

    2014-01-01

    Pneumatic muscle actuators (PMAs) have a high power to weight ratio and possess unique characteristics which make them ideal actuators for applications involving human interaction. PMAs are difficult to control due to nonlinear dynamics, presenting challenges in system implementation. Despite these challenges, PMAs have great potential as a source of resistance for strength training and rehabilitation. The objective of this work was to control a PMA for use in isokinetic exercise, potentially benefiting anyone in need of optimal strength training through a joint's range of motion. A human quadriceps dynamic simulator (HQDS) was developed so that control effectiveness and accommodation could be tested prior to human implementation. The experimental set-up and HQDS are discussed in Part I of this work. The development of a PMA haptic controller and its interaction with the HQDS are discussed in Part II.

  8. Efficacy of pre-exercise low-level laser therapy on isokinetic muscle performance in individuals with type 2 diabetes mellitus: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Gomes, Cid André Fidelis de Paula; Leal-Junior, Ernesto Cesar Pinto; Biasotto-Gonzalez, Daniela Aparecida; El-Hage, Yasmin; Politti, Fabiano; Gonzalez, Tabajara de Oliveira; Dibai-Filho, Almir Vieira; de Oliveira, Adriano Rodrigues; Frigero, Marcelo; Antonialli, Fernanda Colella; Vanin, Adriane Aver; de Tarso Camillo de Carvalho, Paulo

    2014-04-09

    Type 2 diabetes, also known non-insulin-dependent diabetes, is the most prevalent type of the disease and involves defects in the secretion and action of insulin. The aim of the proposed study is to evaluate the efficacy of pre-exercise low-level laser therapy (LLLT) on muscle performance of the quadriceps femoris in individuals with type 2 diabetes. A double-blind, randomized, controlled clinical trial will be carried out in two treatment phases. In the first phase, quadriceps muscle performance will be evaluated using an isokinetic dynamometer and the levels of creatine kinase and lactate dehydrogenase (biochemical markers of muscle damage) will be determined. The participants will then be allocated to four LLLT groups through a randomization process using opaque envelopes: Group A (4 Joules), Group B (6 Joules), Group C (8 Joules) and Group D (0 Joules; placebo). Following the administration of LLLT, the participants will be submitted to an isokinetic eccentric muscle fatigue protocol involving the quadriceps muscle bilaterally. Muscle performance and biochemical markers of muscle damage will be evaluated again immediately after as well as 24 and 48 hours after the experimental protocol. One week after the last evaluation the second phase will begin, during which Groups A, B and C will receive the LLLT protocol that achieved the best muscle performance in phase 1 for a period of 4 weeks. At the end of this period, muscle performance will be evaluated again. The protocol for this study is registered with the World Health Organization under Universal Trial Number U1111-1146-7109. The purpose of this randomized clinical trial is to evaluate the efficacy of pre-exercise LLLT on the performance of the quadriceps muscle (peak torque, total muscle work, maximum power and fatigue index - normalized by body mass) in individuals with DM-2. The study will support the practice of evidence-based to the use of LLLT in improving muscle performance in Individuals with DM-2

  9. Predictors of chronic ankle instability: Analysis of peroneal reaction time, dynamic balance and isokinetic strength.

    Science.gov (United States)

    Sierra-Guzmán, Rafael; Jiménez, Fernando; Abián-Vicén, Javier

    2018-05-01

    Previous studies have reported the factors contributing to chronic ankle instability, which could lead to more effective treatments. However, factors such as the reflex response and ankle muscle strength have not been taken into account in previous investigations. Fifty recreational athletes with chronic ankle instability and 55 healthy controls were recruited. Peroneal reaction time in response to sudden inversion, isokinetic evertor muscle strength and dynamic balance with the Star Excursion Balance Test and the Biodex Stability System were measured. The relationship between the Cumberland Ankle Instability Tool score and performance on each test was assessed and a backward multiple linear regression analysis was conducted. Participants with chronic ankle instability showed prolonged peroneal reaction time, poor performance in the Biodex Stability System and decreased reach distance in the Star Excursion Balance Test. No significant differences were found in eversion and inversion peak torque. Moderate correlations were found between the Cumberland Ankle Instability Tool score and the peroneal reaction time and performance on the Star Excursion Balance Test. Peroneus brevis reaction time and the posteromedial and lateral directions of the Star Excursion Balance Test accounted for 36% of the variance in the Cumberland Ankle Instability Tool. Dynamic balance deficits and delayed peroneal reaction time are present in participants with chronic ankle instability. Peroneus brevis reaction time and the posteromedial and lateral directions of the Star Excursion Balance Test were the main contributing factors to the Cumberland Ankle Instability Tool score. No clear strength impairments were reported in unstable ankles. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. The relationship between previous hamstring injury and the concentric isokinetic knee muscle strength of irish gaelic footballers

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    O'Ceallaigh Brian

    2008-03-01

    Full Text Available Abstract Background Hamstring injury is one of the most common injuries affecting gaelic footballers, similar to other field sports. Research in other sports on whether residual hamstring weakness is present after hamstring injury is inconsistent, and no study has examined this factor in irish gaelic footballers. The aim of this study was to examine whether significant knee muscle weakness is present in male Irish gaelic footballers who have returned to full activity after hamstring injury. Methods The concentric isokinetic knee flexion and extension strength of 44 members of a university gaelic football team was assessed at 60, 180 and 300 degrees per second using a Contrex dynamometer. Results Fifteen players (34% reported a history of hamstring strain, with 68% of injuries affecting the dominant (kicking limb. The hamstrings were significantly stronger (p 0.05 using this comparison. The previously unilaterally injured hamstrings were significantly weaker (p Conclusion Hamstring muscle weakness was observed in male Irish gaelic footballers with a history of hamstring injury. This weakness is most evident when comparisons are made to multiple control populations, both within and between subjects. The increased strength of the dominant limb should be considered as a potential confounding variable in future trials. The study design does not allow interpretation of whether these changes in strength were present before or after injury.

  11. [Isokinetic assessment with two years follow-up of anterior cruciate ligament reconstruction with patellar tendon or hamstring tendons].

    Science.gov (United States)

    Condouret, J; Cohn, J; Ferret, J-M; Lemonsu, A; Vasconcelos, W; Dejour, D; Potel, J-F

    2008-12-01

    This retrospective multicentric study was designed to assess the outcome of quadriceps and hamstrings muscles two years after Anterior Cruciate Ligament (ACL) reconstruction and compare muscles recovery depending on the type of graft and individual variables like age, gender, level of sport, but also in terms of discomfort, pain and functional score. The results focused on the subjective and objective IKDC scores, SF36, the existence or not of subjective disorders and their location. The review included isokinetic muscle tests concentric and eccentric extensors/flexors but also internal rotators/external rotators with analysis of mean work and mean power. One hundred and twenty-seven patients were included with an average age 29 years (+/-10). They all had an ACL reconstruction with patellar tendon or hamstring tendon with single or double bundles. In the serie, the average muscles deficit at two years was 10% for the flexors and extensors but with a significant dispersion. Significant differences were not noted in the mean values of all parameters in term of sex or age (over 30 years or not), neither the type of sport, nor of clinical assessment (Class A and B of objective IKDC score), nor the existence of anterior knee pain. There was a relationship between the level of extensor or flexor recovery and the quality of functional results with minimal muscle deficits close to 5% if the IKDC score was over 90 and deficits falling to 15% in the group with IKDC score less than 90. The type of reconstruction (patellar tendon versus hamstrings) had an influence on the muscle deficit. For extensors, the recovery was the same in the two groups, more than 90% at two years and the distribution of these two populations by level of deficit was quite the same. For flexors, residual deficits were significantly higher in the hamstrings group on the three studied parameters whatever the speed and the type of contraction (concentric or eccentric) with an average deficit of 14 to 18

  12. Complex myograph allows the examination of complex muscle contractions for the assessment of muscle force, shortening, velocity, and work in vivo

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    Ruhschulte Hainer

    2008-07-01

    Full Text Available Abstract Background The devices used for in vivo examination of muscle contractions assess only pure force contractions and the so-called isokinetic contractions. In isokinetic experiments, the extremity and its muscle are artificially moved with constant velocity by the measuring device, while a tetanic contraction is induced in the muscle, either by electrical stimulation or by maximal voluntary activation. With these systems, experiments cannot be performed at pre-defined, constant muscle length, single contractions cannot be evaluated individually and the separate examination of the isometric and the isotonic components of single contractions is not possible. Methods The myograph presented in our study has two newly developed technical units, i.e. a. a counterforce unit which can load the muscle with an adjustable, but constant force and b. a length-adjusting unit which allows for both the stretching and the contraction length to be infinitely adjustable independently of one another. The two units support the examination of complex types of contraction and store the counterforce and length-adjusting settings, so that these conditions may be accurately reapplied in later sessions. Results The measurement examples presented show that the muscle can be brought to every possible pre-stretching length and that single isotonic or complex isometric-isotonic contractions may be performed at every length. The applied forces act during different phases of contraction, resulting into different pre- and after-loads that can be kept constant – uninfluenced by the contraction. Maximal values for force, shortening, velocity and work may be obtained for individual muscles. This offers the possibility to obtain information on the muscle status and to monitor its changes under non-invasive measurement conditions. Conclusion With the Complex Myograph, the whole spectrum of a muscle's mechanical characteristics may be assessed.

  13. Effects of Six Weeks of Medicine Ball Training on Throwing Velocity, Throwing Precision, and Isokinetic Strength of Shoulder Rotators in Female Handball Players.

    Science.gov (United States)

    Raeder, Christian; Fernandez-Fernandez, Jaime; Ferrauti, Alexander

    2015-07-01

    The aim of this study was to investigate the effects of 6 weeks of medicine ball training (MBT) on throwing velocity, throwing precision, and isokinetic strength of shoulder rotators in competitive female handball players. Twenty-eight players (mean ± SD; age: 20.8 ± 3.3 years, height: 170.5 ± 5.6 cm, body mass: 65.2 ± 8.0 kg) were randomly assigned to an MBT group (TG; n = 15) and a control group (CG; n = 13). TG performed a supervised MBT program, 3 times a week for a total of 6 weeks, focusing on handball-specific movement patterns. Both groups, TG and CG, also conducted a supervised shoulder injury prevention program with elastic tubes, as part of the warm-up, finishing with regular handball throws. Results showed a significant group × time interaction in throwing velocity (p handball players, whereas throwing precision remained unaffected. Medicine ball training exercises seem to be a useful and inexpensive strength training strategy in enhancing functional performance by closely mimicking sport-specific movement activities.

  14. Stretching of Active Muscle Elicits Chronic Changes in Multiple Strain Risk Factors.

    Science.gov (United States)

    Kay, Anthony David; Richmond, Dominic; Talbot, Chris; Mina, Minas; Baross, Anthony William; Blazevich, Anthony John

    2016-07-01

    The muscle stretch intensity imposed during "flexibility" training influences the magnitude of joint range of motion (ROM) adaptation. Thus, stretching while the muscle is voluntarily activated was hypothesized to provide a greater stimulus than passive stretching. The effect of a 6-wk program of stretch imposed on an isometrically contracting muscle (i.e., qualitatively similar to isokinetic eccentric training) on muscle-tendon mechanics was therefore studied in 13 healthy human volunteers. Before and after the training program, dorsiflexion ROM, passive joint moment, and maximal isometric plantarflexor moment were recorded on an isokinetic dynamometer. Simultaneous real-time motion analysis and ultrasound imaging recorded gastrocnemius medialis muscle and Achilles tendon elongation. Training was performed twice weekly and consisted of five sets of 12 maximal isokinetic eccentric contractions at 10°·s. Significant increases (P tendon stiffness) was detected (-1.5%, P > 0.05), a significant increase in tendon stiffness (31.2%, P tendon stiffness simultaneous with significant increases in tendon stiffness and decreases in passive muscle stiffness indicates that tissue-specific effects were elicited.

  15. The effect of warm-ups with stretching on the isokinetic moments of collegiate men.

    Science.gov (United States)

    Park, Hyoung-Kil; Jung, Min-Kyung; Park, Eunkyung; Lee, Chang-Young; Jee, Yong-Seok; Eun, Denny; Cha, Jun-Youl; Yoo, Jaehyun

    2018-02-01

    Performing warm-ups increases muscle temperature and blood flow, which contributes to improved exercise performance and reduced risk of injuries to muscles and tendons. Stretching increases the range of motion of the joints and is effective for the maintenance and enhancement of exercise performance and flexibility, as well as for injury prevention. However, stretching as a warm-up activity may temporarily decrease muscle strength, muscle power, and exercise performance. This study aimed to clarify the effect of stretching during warm-ups on muscle strength, muscle power, and muscle endurance in a nonathletic population. The subjects of this study consisted of 13 physically active male collegiate students with no medical conditions. A self-assessment questionnaire regarding how well the subjects felt about their physical abilities was administered to measure psychological readiness before and after the warm-up. Subjects performed a non-warm-up, warm-up, or warm-up regimen with stretching prior to the assessment of the isokinetic moments of knee joints. After the measurements, the respective variables were analyzed using nonparametric tests. First, no statistically significant intergroup differences were found in the flexor and extensor peak torques of the knee joints at 60°/sec, which were assessed to measure muscle strength. Second, no statistically significant intergroup differences were found in the flexor and extensor peak torques of the knee joints at 180°/sec, which were assessed to measure muscle power. Third, the total work of the knee joints at 240°/sec, intended to measure muscle endurance, was highest in the aerobic-stretch-warm-ups (ASW) group, but no statistically significant differences were found among the groups. Finally, the psychological readiness for physical activity according to the type of warm-up was significantly higher in ASW. Simple stretching during warm-ups appears to have no effect on variables of exercise physiology in nonathletes

  16. THE EFFICACY OF ANGLE-MATCHED ISOKINETIC KNEE FLEXOR AND EXTENSOR STRENGTH PARAMETERS IN PREDICTING AGILITY TEST PERFORMANCE.

    Science.gov (United States)

    Greig, Matt; Naylor, James

    2017-10-01

    Agility is a fundamental performance element in many sports, but poses a high risk of injury. Hierarchical modelling has shown that eccentric hamstring strength is the primary determinant of agility performance. The purpose of this study was to investigate the relationship between knee flexor and extensor strength parameters and a battery of agility tests. Controlled laboratory study. Nineteen recreational intermittent games players completed an agility battery and isokinetic testing of the eccentric knee flexors (eccH) and concentric knee extensors (conQ) at 60, 180 and 300°·s -1 . Peak torque and the angle at which peak torque occurred were calculated for eccH and conQ at each speed. Dynamic control ratios (eccH:conQ) and fast:slow ratios (300:60) were calculated using peak torque values, and again using angle-matched data, for eccH and conQ. The agility test battery differentiated linear vs directional changes and prescriptive vs reactive tasks. Linear regression showed that eccH parameters were generally a better predictor of agility performance than conQ parameters. Stepwise regression showed that only angle-matched strength ratios contributed to the prediction of each agility test. Trdaitionally calculated strength ratios using peak torque values failed to predict performance. Angle-matched strength parameters were able to account for 80% of the variation in T-test performance, 70% of deceleration distance, 55% of 10m sprint performance, and 44% of reactive change of direction speed. Traditionally calculated strength ratios failed to predict agility performance, whereas angle-matched strength ratios had better predictive ability and featured in a predictive stepwise model for each agility task. 2c.

  17. Early postoperative repair status after rotator cuff repair cannot be accurately classified using questionnaires of patient function and isokinetic strength evaluation.

    Science.gov (United States)

    Colliver, Jessica; Wang, Allan; Joss, Brendan; Ebert, Jay; Koh, Eamon; Breidahl, William; Ackland, Timothy

    2016-04-01

    This study investigated if patients with an intact tendon repair or partial-thickness retear early after rotator cuff repair display differences in clinical evaluations and whether early tendon healing can be predicted using these assessments. We prospectively evaluated 60 patients at 16 weeks after arthroscopic supraspinatus repair. Evaluation included the Oxford Shoulder Score, 11-item version of the Disabilities of the Arm, Shoulder and Hand, visual analog scale for pain, 12-item Short Form Health Survey, isokinetic strength, and magnetic resonance imaging (MRI). Independent t tests investigated clinical differences in patients based on the Sugaya MRI rotator cuff classification system (grades 1, 2, or 3). Discriminant analysis determined whether intact repairs (Sugaya grade 1) and partial-thickness retears (Sugaya grades 2 and 3) could be predicted. No differences (P repair was intact. The ability to discriminate between groups was enhanced with up to 5 variables entered; however, only 87% of the partial-retear group and 36% of the intact-repair group were correctly classified. No differences in clinical scores existed between patients stratified by the Sugaya MRI classification system at 16 weeks. An intact repair or partial-thickness retear could not be accurately predicted. Our results suggest that correct classification of healing in the early postoperative stages should involve imaging. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  18. Pelvic floor muscle training decreases hip adductors isometric peak torque in incontinent women: an exploratory study

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    Grasiéla Nascimento Correia

    Full Text Available INTRODUCTION: The pelvic floor muscle (PFM training is the most common treatment for urinary incontinence (UI, however many women performed the contraction of PFM with associated contraction of abdominal, gluteus and hip adductors muscles. OBJECTIVE: To assess the effects of pelvic floor muscle (PFM training on isometric and isokinetic hip adductors peak torque (PT among women suffering from urinary incontinence (UI. MATERIALS AND METHODS: It is a longitudinal and prospective exploratory study. This study included 15 physically active women aged 45 years old and over, who presented complaints of UI. The PFM function (digital evaluation and perineometry, isometric and isokinetic hip adductors PT and one hour pad test were performed before and after treatment. The PFM training was performed in group, one hour once a week for 12 sessions. RESULTS: Significant improvement of PFM function and pressure level (p = 0.003, and significant decrease of hip adductors isometric PT and one-hour pad test, were found post-treatment. Moderate negative correlations between PFM contraction pressure and hip adductors isokinetic PT for dominant side (DS (r = -0.62; p = 0.03 and non-dominant side (NDS (r = -0.64; p = 0.02; and between PFM fast fibers contraction and hip adductors isometric PT for DS (r = -0.60; p = 0.03 and NDS (r = -0.59; p = 0.04 were also found. CONCLUSIONS: The PFM training decreased hip adductors PT and improved PFM functions and UI.

  19. Isokinetic and isometric strength-endurance after 6 hours of immersion and 6 degrees head-down tilt in men

    Science.gov (United States)

    Shaffer-Bailey, M.; Greenleaf, J. E.; Hutchinson, T. M.

    1996-01-01

    PURPOSE: To determine weight (water) loss levels for onset of muscular strength and endurance changes during deconditioning. METHODS: Seven men (27-40 yr) performed maximal shoulder-, knee-, and ankle-joint isometric (0 degree.s(-1) load) and isokinetic (60 degrees, 120 degrees, 180 degrees.s(-1) velocity) exercise tests during ambulatory control (AC), after 6 h of 6 degrees head-down tilt (HDT; dry-bulb temp. = 23.2 +/- SD 0.6 degrees C, relative humidity = 31.1+/- 11.1%) and after 6 h of 80 degrees foot-down head-out water immersion (WI; water temp. = 35.0 +/- SD 0.1 degree C) treatments. RESULTS: Weight (water) loss after HDT (1.10 +/- SE 0.14 kg, 1.4 +/- 0.2% body wt) and WI (1.54+/- 0.19 kg, 2.0 +/- 0.2% body wt) were not different, but urinary excretion with WI (1,354 +/- 142 ml.6 h(-1)) was 28% greater (p strength was unchanged except for three knee-joint peak torques: AC torque (120 degrees.s(-1), 285 +/- 20 Nm) decreased to 268 +/- 21 Nm (delta = -6%, p strength and endurance decrements is more than 2% body weight (water) loss, while significant reduction in knee-joint muscular strength-endurance occurred only at moderate (120 degrees.s(-1) and lighter (180 degrees.s(-1)) loads with body weight loss of 1.4-2.0% following WI or HDT, respectively. These weight (water) losses and knee-joint strength decrements are somewhat less than the mean weight loss of 2.6% and knee-joint strength decrements of 6-20% of American astronauts after Skylab flights to 84 d.

  20. ANALYSIS OF ISOKINETIC KNEE EXTENSION / FLEXION IN MALE ELITE ADOLESCENT WRESTLERS

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    Sanli Sadi Kurdak

    2005-12-01

    Full Text Available Wrestling requires strength of the upper and lower body musculature which is critical for the athletic performance. Evaluation of the adolescent's skeletal muscle is important to understand body movement, especially including those involved in sports. Strength, power and endurance capacity are defined as parameters of skeletal muscle biomechanical properties. The isokinetic dynamometer is an important toll for making this type of evaluation. However, load range phase of range of motion has to be considered to interpret the data correctly. With this in mind we aimed to investigate the lover body musculature contractile characteristics of adolescent wrestlers together with detailed analyses of load range phase of motion. Thirteen boys aged 12 - 14 years participated to this study. Concentric load range torque, work and power of knee extension and flexion were measured by a Cybex Norm dynamometer at angular velocities from 450°/sec to 30°/sec with 30°/sec decrements for each set. None of the wrestlers were able to attain load range for angular velocities above 390°/sec and 420°/sec for extension and flexion respectively. Detailed analyses of the load range resulted in statistically significant differences in the normalized load range peak torque for extension at 270°/sec (1.44 ± 0.28 Nm·kg-1 and 1.14 ± 0.28 Nm·kg-1 for total and load range peak torque respectively, p < 0.05, and for flexion at 300°/sec (1.26 ± 0.28 Nm·kg-1 and 1.03 ± 0.23 Nm·kg-1 for total and load range peak torque respectively, p < 0.05, compared to total peak torque data. Similarly, the significant difference was found for the work values at 90°/sec (1.91 ± 0.23 Nm·kg-1 and 1.59 ± 0.24 Nm·kg-1 for total and load range work respectively for extension and 1.73 ± 0.21 Nm·kg-1 and 1.49 ± 0.19 Nm·kg-1 for total and load range work respectively for flexion, p < 0.05, and was evident at higher angular velocities (p < 0.001 for both extension and flexion. At

  1. Dinamometria isocinética de tronco em nadadores de diferentes estilos Isokinetic trunk dynamometry in diferent swimming strokes

    Directory of Open Access Journals (Sweden)

    Leonardo Luiz Barretti Secchi

    2010-01-01

    Full Text Available OBJETIVOS: Comparar a atividade muscular dos músculos flexores e extensores de tronco entre estilos de nado assimétrico e nado simétrico. MÉTODO: Catorze nadadores da elite, velocistas e especialistas em um dos quatro estilos da natação sem história prévia de lesões.. Divididos em dois grupos de sete atletas: 1. Grupo nado assimétrico (GNA: constituído por cinco atletas que nadam o estilo crawl e dois atletas que nadam o estilo costas. 2. Grupo nado simétrico (GNS formado por sete atletas: quatro atletas nadadores no estilo peito e três nadadores no estilo borboleta. Todos foram avaliados no dinamômetro isocinético Cybex 6000. RESULTADOS: O tempo de aceleração na velocidade de 120º/ s do grupo flexor do tronco foi maior no GNS (p=0,054. A potência do grupo extensor nas velocidades de 90 e 120º/ segundo foi maior no GNA que no GNS (p=0,053 e 0,052 respectivamente. Não houve diferença estatística significante nas demais variáveis analisadas. CONCLUSÃO: Os nados assimétricos (crawl e costas proporcionam uma resposta muscular (recrutamento mais eficiente nos grupo dos flexores do tronco, possivelmente pela manutenção constante da contração isométrica dos músculos abdominais.OBJECTIVE: To compare the effect of asymmetric and symmetric swimming strokes on muscle activity of the trunk flexor and extensor muscles. METHODS: Fourteen elite speed swimmers, specialists in one of four swimming styles, all without any history of spinal cord injury, were divided in two groups: 1 asymmetric group, consisting of five athletes specializing in the freestyle stroke and three in the backstroke; and 2 symmetric group, consisting of four athletes specializing in the butterfly stroke and three in the breaststroke. All the swimmers were assessed using a Cybex 6000 isokinetic dynamometer. RESULTS: The acceleration time for the trunk flexor group at a speed of 120º per second was greater in the symmetric group (p=0.054. The power of the

  2. Comparison of knee flexion isokinetic deficits between seated and prone positions after ACL reconstruction with hamstrings graft: Implications for rehabilitation and return to sports decisions.

    Science.gov (United States)

    Koutras, Georgios; Bernard, Manfred; Terzidis, Ioannis P; Papadopoulos, Pericles; Georgoulis, Anastasios; Pappas, Evangelos

    2016-07-01

    Hamstrings grafts are commonly used in ACL reconstruction, however, the effect of graft harvesting on knee flexion strength has not been longitudinally evaluated in functional positions. We hypothesized that greater deficits in knee flexion strength exist in the prone compared to the seated position and these deficits remain as rehabilitation progresses. Case series. Forty-two consecutive patients who underwent ACL reconstruction with a hamstrings graft were followed prospectively for 9 months. Isokinetic knee flexion strength at a slow and a fast speed were collected at 3, 4, 6, and 9 months in two different positions: conventional (seated) and functional (0° of hip flexion). Peak torque knee flexion deficits were higher in the prone position compared to the seated position by an average of 6.5% at 60°/s and 9.1% at 180°/s (p<0.001). Measuring knee flexion strength in prone demonstrates higher deficits than in the conventional seated position. Most athletes would not be cleared to return to sports even at 9 months after surgery with this method. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  3. The effects of a repeated bout of eccentric exercise on indices of muscle damage and delayed onset muscle soreness.

    Science.gov (United States)

    Paddon-Jones, D; Muthalib, M; Jenkins, D

    2000-03-01

    This study examined markers of muscle damage following a repeated bout of maximal isokinetic eccentric exercise performed prior to full recovery from a previous bout. Twenty non-resistance trained volunteers were randomly assigned to a control (CON, n=10) or experimental (EXP, n=10) group. Both groups performed 36 maximal isokinetic eccentric contractions of the elbow flexors of the non-dominant arm (ECC1). The EXP group repeated the same eccentric exercise bout two days later (ECC2). Total work and peak eccentric torque were recorded during each set of ECC1 and ECC2. Isometric torque, delayed onset muscle soreness (DOMS), flexed elbow angle and plasma creatine kinase (CK) activity were measured prior to and immediately following ECC1 and ECC2. at 24h intervals for 7 days following ECC1 and finally on day 11. In both groups, all dependent variables changed significantly during the 2 days following ECC1. A further acute post-exercise impairment in isometric torque (30 +/- 5%) and flexed elbow angle (20 +/- 4%) was observed following ECC2 (p0.05). These findings suggest that when maximal isokinetic eccentric exercise is repeated two days after experiencing of contraction-induced muscle damage, the recovery time course is not significantly altered.

  4. Effects of a single whole body cryotherapy (-110°C) bout on neuromuscular performance of the elbow flexors during isokinetic exercise.

    Science.gov (United States)

    Ferreira-Junior, J B; Vieira, C A; Soares, S R S; Guedes, R; Rocha Junior, V A; Simoes, H G; Brown, L E; Bottaro, M

    2014-12-01

    It has been demonstrated that body cooling may decrease neuromuscular performance. However, the effect of a single session of whole body cryotherapy (-110°C) on neuromuscular performance has not been well documented. Thus, the aim of this study was to evaluate the effects of a single exposure of WBC on elbow flexor neuromuscular performance. Thirteen physically active, healthy young men (age=27.9±4.2 years, mass=79.4±9.7 kg, height=176.7±5.2 cm) were randomly exposed to 2 different experimental conditions separated by a minimum of 72 h: 1) whole body cryotherapy- 3 min at -110°C; 2) control- 3 min at 21°C. All subjects were tested for maximal isokinetic elbow flexion at 60°.s(-1) 30 min before and 10 min after each condition. There were no significant differences in peak torque, average power, total work or muscle activity between conditions. Peak torque was lower at post-test compared to pre-test in both conditions (F=6.58, p=0.025). However, there were no differences between pre-test and post-test for any other variables. These results indicate that strength specialists, athletic trainers and physical therapists might utilize whole body cryotherapy before training or rehabilitation without compromising neuromuscular performance of the elbow flexors. © Georg Thieme Verlag KG Stuttgart · New York.

  5. Isokinetic assessment of knee flexor/extensor muscular strength in elderly women Avaliação isocinética do torque muscular flexor-extensor do joelho em mulheres com idade entre 75-83 anos

    Directory of Open Access Journals (Sweden)

    Marcos de Amorim Aquino

    2002-08-01

    Full Text Available OBJECTIVE: To assess knee flexor-extensor muscular strength in elderly women with no previous history of musculoskeletal disorders on the lower limbs using an isokinetic dynamometer, in order to obtain data that could be used as a comparative parameter in the evaluation of elderly women with knee disorders, thus facilitating a better rehabilitation of these patients. METHODS: Twenty-six volunteers aged 75 to 83 years were studied using a Cybex® 6000 isokinetic dynamometer. The chosen angular velocity was 60 º/s, and concentric exercise was used for either flexion or extension. The studied parameters were: peak torque, angle of peak torque, and flexor-extensor torque rate. RESULTS: There were no differences between dominant (D and nondominant (ND knee peak torque values. This was true for both flexor (D = 42.46 ± 9.09 Nm / ND = 40.65 ± 9.38 Nm and extensor (D = 76.92 ± 13.97 Nm / ND = 77.65 ± 15.21 Nm movements. The descriptive statistical analysis of the values obtained for the flexor-extensor peak torque rate and for the angle of occurrence of peak torque was the same for the dominant and nondominant sides. CONCLUSIONS: The values of peak torque for the contralateral side can be used as a reference during rehabilitation of elderly women with acute disease of the knee, and the angular velocity of 60 º/s is proper and safe for isokinetic assessment of elderly people.OBJETIVO: Avaliar, isocineticamente, o torque dos músculos flexores e extensores dos joelhos de mulheres idosas sem afecções do sistema músculo-esquelético em membros inferiores, obtendo dados que possam servir como parâmetro de comparação na avaliação de mulheres idosas portadoras de afecções nos joelhos, colaborando para uma melhor reabilitação dessas pacientes. CASUÍSTICA E MÉTODOS: Vinte e seis voluntárias foram avaliadas. O estudo foi realizado através de um dinamômetro isocinético marca CYBEXâ modelo 6000 na velocidade angular de 60º/s. O tipo do

  6. Significance of acceleration period in a dynamic strength testing study.

    Science.gov (United States)

    Chen, W L; Su, F C; Chou, Y L

    1994-06-01

    The acceleration period that occurs during isokinetic tests may provide valuable information regarding neuromuscular readiness to produce maximal contraction. The purpose of this study was to collect the normative data of acceleration time during isokinetic knee testing, to calculate the acceleration work (Wacc), and to determine the errors (ERexp, ERwork, ERpower) due to ignoring Wacc during explosiveness, total work, and average power measurements. Seven male and 13 female subjects attended the test by using the Cybex 325 system and electronic stroboscope machine for 10 testing speeds (30-300 degrees/sec). A three-way ANOVA was used to assess gender, direction, and speed factors on acceleration time, Wacc, and errors. The results indicated that acceleration time was significantly affected by speed and direction; Wacc and ERexp by speed, direction, and gender; and ERwork and ERpower by speed and gender. The errors appeared to increase when testing the female subjects, during the knee flexion test, or when speed increased. To increase validity in clinical testing, it is important to consider the acceleration phase effect, especially in higher velocity isokinetic testing or for weaker muscle groups.

  7. Efeito do intervalo de recuperação entre séries de extensões isocinéticas de joelho em homens jovens destreinados Effect of recovery interval between sets of isokinetic knee extensions among untrained young men

    Directory of Open Access Journals (Sweden)

    R Celes

    2009-08-01

    Full Text Available OBJETIVO: Avaliar o efeito de dois diferentes Intervalos de Recuperação (IR entre séries de extensões isocinéticas de joelho no Pico de Torque (PT e no Trabalho Total (TT em jovens destreinados. MÉTODOS: Dezoito homens (24,22±2,58 anos; 80,42±11,41 kg realizaram três séries de 10 extensões isocinéticas com o joelho direito a 60° e 180°/s. O IR entre as séries foram de 1 e 2 minutos, contrabalanceados entre os dois dias de teste, separados por, no mínimo, 48 horas. A taxa de trabalho-recuperação foi de 1:3 e 1:6 para 60°/s e 1:6 e 1:12 para 180°/s. Os voluntários não participavam de programas de treinamento resistido há pelo menos 6 meses. A análise estatística foi a ANOVA de medidas repetidas 2 x 3 [IR (1 e 2 minutos x série (1ª, 2ª e 3ª]. O nível de significância foi aOBJECTIVE: To assess the effect of two recovery intervals (RIs between sets of isokinetic knee extension exercises on peak torque (PT and total work (TW, among untrained young men. METHODS: Eighteen men (24.22±2.58 years; 80.42±11.41 kg performed three sets of ten isokinetic extensions of the right knee, at 60° and 180°/s. The RIs between the sets were one and two minutes long, spread over two test days separated by a minimum of 48 hours. The work-to-recovery ratio was 1:3 and 1:6 for 60°/s, and 1:6 and 1:12 for 180°/s. The subjects had not participated in any resistance training programs within the last six months. The statistical analysis consisted of 2 x 3 repeated-measures ANOVA [RI (one or two minutes x set (1st, 2nd or 3rd]. The significance level was a<0.05. RESULTS: Neither one minute nor two minutes RIs maintained the PT and TW throughout the three sets (p<0.05. However, at 60°/s, two minutes RIs enabled better PT and TW in the second and third sets than one minute RIs (p<0.05. At 180°/s, two minutes RIs were only better (p<0.05 than one minute RIs for TW in the third set. CONCLUSION: This study indicated that, during an isokinetic

  8. Comparison of coarse coal dust sampling techniques in a laboratory-simulated longwall section.

    Science.gov (United States)

    Patts, Justin R; Barone, Teresa L

    2017-05-01

    Airborne coal dust generated during mining can deposit and accumulate on mine surfaces, presenting a dust explosion hazard. When assessing dust hazard mitigation strategies for airborne dust reduction, sampling is done in high-velocity ventilation air, which is used to purge the mining face and gallery tunnel. In this environment, the sampler inlet velocity should be matched to the air stream velocity (isokinetic sampling) to prevent oversampling of coarse dust at low sampler-to-air velocity ratios. Low velocity ratios are often encountered when using low flow rate, personal sampling pumps commonly used in underground mines. In this study, with a goal of employing mine-ready equipment, a personal sampler was adapted for area sampling of coarse coal dust in high-velocity ventilation air. This was done by adapting an isokinetic nozzle to the inlet of an Institute of Occupational Medicine (Edinburgh, Scotland) sampling cassette (IOM). Collected dust masses were compared for the modified IOM isokinetic sampler (IOM-MOD), the IOM without the isokinetic nozzle, and a conventional dust sampling cassette without the cyclone on the inlet. All samplers were operated at a flow rate typical of personal sampling pumps: 2 L/min. To ensure differences between collected masses that could be attributed to sampler design and were not influenced by artifacts from dust concentration gradients, relatively uniform and repeatable dust concentrations were demonstrated in the sampling zone of the National Institute for Occupational Safety and Health experimental mine gallery. Consistent with isokinetic theory, greater differences between isokinetic and non-isokinetic sampled masses were found for larger dust volume-size distributions and higher ventilation air velocities. Since isokinetic sampling is conventionally used to determine total dust concentration, and isokinetic sampling made a difference in collected masses, the results suggest when sampling for coarse coal dust the IOM-MOD may

  9. Peak torque and knee kinematics during gait after eccentric isokinetic training of quadriceps in healthy subjects O pico de torque e a cinemática do joelho durante a marcha após treino isocinético excêntrico do quadríceps em sujeitos saudáveis

    Directory of Open Access Journals (Sweden)

    PR Poletto

    2008-08-01

    Full Text Available OBJECTIVE: To evaluate the effects of eccentric isokinetic training on knee range of motion (ROM of healthy subjects. METHODS: The knee extensor and flexor isokinetic peak torques and ROM of flexion/extension and varus/valgus knee movements during gait of 18 healthy men (21.7±2.2 years; 1.73±0.10m; 68.7±9.4kg; body mass index: 22.6±2kg/m² were analyzed, before and after six weeks of bilateral eccentric isokinetic training of the knee extensors at 30º/s. RESULTS: The knee extensor torque increased in both limbs (right, from 229±54 to 304±53Nm; pOBJETIVO: Avaliar os efeitos do treino isocinético excêntrico sobre a amplitude de movimento (ADM do joelho em sujeitos saudáveis. MÉTODOS: Foram analisados os picos de torque isocinético dos extensores e flexores do joelho e a ADM de flexo/extensão e valgo/varo, durante a marcha, de 18 homens saudáveis (21,7±2,2 anos; 1,73±0,10m; 68,7±9,4kg; índice de massa corpórea: 22,6±2kg/m² antes e após seis semanas de treino isocinético excêntrico bilateral dos extensores do joelho a 30º/s. RESULTADOS: O torque extensor do joelho aumentou em ambos os membros, direito (de 229±54 para 304±53Nm; p<0,01 e esquerdo (de 228±59 para 311±63Nm; p<0,01 sem diferença de ganho de torque entre eles. O pico de torque flexor aumentou (de 114±30 para 123±22Nm; p<0,05, mas a razão isquiotibiais/quadríceps (I/Q diminuiu (de 0,5±0,08 para 0,39±0,07; p<0,01 após o treino. Não houve diferença para os movimentos de flexo/extensão e valgo/varo após o treino, exceto uma pequena mudança (4° no valgo para o joelho esquerdo. CONCLUSÕES: O treino isocinético excêntrico dos extensores do joelho aumentou o torque extensor e diminuiu a razão I/Q, entretanto o efeito sobre o padrão da marcha parece desprezível em sujeitos saudáveis. Um treino associado dos flexores, complementar ao treino dos extensores parece ser necessário para o equilíbrio entre agonistas e antagonistas do joelho.

  10. Thoracic posture, shoulder muscle activation patterns and isokinetic ...

    African Journals Online (AJOL)

    Poor posture, scapular dyskinesia, altered scapular muscle recruitment patterns and ... postural deviation and incorrect shoulder kinematics.[5]. Knowledge of the .... the contra-lateral hand was placed as far down the spinal column as possible, and the ... produced by muscle contraction for rotation around a joint.[12] During.

  11. Muscle strength and power in persons with multiple sclerosis - A systematic review and meta-analysis.

    Science.gov (United States)

    Jørgensen, Mlk; Dalgas, U; Wens, I; Hvid, L G

    2017-05-15

    Multiple sclerosis (MS) is a chronic disease in the central nervous system which causes a number of physical symptoms including impairments of muscle mechanical function (muscle strength, muscle power and explosive muscle strength (~rate of force development, RFD)). However, a full overview of the existing knowledge regarding muscle mechanical function in persons with MS (PwMS) is still pending. To systematically review 1) the psychometric properties of isokinetic dynamometry testing in PwMS, and 2) studies comparing muscle mechanical function in PwMS to matched healthy controls (HC). In addition, a meta-analysis will evaluate 3) the effects of progressive resistance training on muscle mechanical function in PwMS. A systematic literature search was performed in eight databases. To be included in the review, the study had to 1) enroll participants with a confirmed diagnosis of MS; 2) assess muscle mechanical function 3) had undergone peer-review. The psychometric properties of isokinetic dynamometry were reviewed with respect to validity, reliability, and responsiveness. Comparison of muscle strength between PwMS and HC was performed across contraction velocities, contraction modes and muscle groups, as were the rate of force development. The effects of progressive resistance training on muscle mechanical function were evaluated in a meta-analysis using a random effects model and standardized mean difference (SMD). A total of four, twenty-four, and ten studies were identified for aim 1, 2, and 3, respectively. High Intraclass correlations coefficients (range: 0.87-0.99) for isokinetic dynamometry was reported when assessing knee extensor and knee flexor muscle strength independent of contraction velocity. Compared to match HC, PwMS display impaired muscle strength, power and explosive muscle strength. Muscle strength impairments were most pronounced during maximal moderate to fast dynamic muscle contractions of the lower extremities. Progressive resistance training

  12. Comparisons in the Recovery Response From Resistance Exercise Between Young and Middle-Aged Men.

    Science.gov (United States)

    Gordon, Joseph A; Hoffman, Jay R; Arroyo, Eliott; Varanoske, Alyssa N; Coker, Nicholas A; Gepner, Yftach; Wells, Adam J; Stout, Jeffrey R; Fukuda, David H

    2017-12-01

    Gordon, JA III, Hoffman, JR, Arroyo, E, Varanoske, AN, Coker, NA, Gepner, Y, Wells, AJ, Stout, JR, and Fukuda, DH. Comparisons in the recovery response from resistance exercise between young and middle-aged men. J Strength Cond Res 31(12): 3454-3462, 2017-The purpose of this study was to compare the effects of a bout of high-volume isokinetic resistance exercise protocol (HVP) on lower-body strength and markers of inflammation and muscle damage during recovery between young and middle-aged adult men. Nineteen recreationally trained men were classified as either a young adult (YA: 21.8 ± 2.0 years; 90.7 ± 11.6 kg) or a middle-aged adult (MA: 47.0 ± 4.4 years; 96.0 ± 21.5 kg) group. The HVP consisted of 8 sets of 10 repetitions, with 1 minute of rest between each set, performed on an isokinetic dynamometer at 60°·s. Maximal voluntary isometric contractions and isokinetic peak torque (PKT) and average torque (AVGT) (measured at 240° and 60°·s, respectively) were assessed at baseline (BL), immediately post (IP), 120 minutes, 24, and 48 hours after HVP. Blood was obtained at BL, IP, 30, 60, 120 minute, 24, and 48 hours after HVP to assess muscle damage and inflammation. All performance data were analyzed using repeated measures analysis of covariance, whereas all inflammatory and muscle damage markers were analyzed using a 2-way (time × group) repeated measures analysis of variance. Results revealed no between-group differences for PKT, AVGT, or rate of torque development at 200 ms (RTD200). No between-group differences in myoglobin, creatine kinase, C-reactive protein, or interleukin-6 were observed. Although BL differences in muscle performance were observed between YA and MA, no between-group differences were noted in performance recovery measures from high-volume isokinetic exercise in recreationally trained men. These results also indicate that the inflammatory and muscle damage response from high-volume isokinetic exercise is similar between

  13. Importance of contraction history on muscle force of porcine urinary bladder smooth muscle.

    Science.gov (United States)

    Menzel, Robin; Böl, Markus; Siebert, Tobias

    2017-02-01

    The purpose of this study was to provide a comprehensive dataset of porcine urinary bladder smooth muscle properties. Particularly, the history dependence of force production, namely force depression (FD) following shortening and force enhancement (FE) following stretch, was analysed. During active micturition, the circumference of the urinary bladder changes enormously. Thus, FD might be an important phenomenon during smooth muscle contraction. Electrically stimulated, intact urinary bladder strips from pigs (n = 10) were suspended in an aerated-filled organ bath, and different isometric, isotonic, and isokinetic contraction protocols were performed to determine the force-length and the force-velocity relation. FD and FE were assessed in concentric and eccentric contractions with different ramp lengths and ramp velocities. Bladder smooth muscles exhibit considerable amounts of FD and FE. The amount of FD increased significantly with ramp length, while FE did not change. However, FE and FD were independent of ramp velocity. The results imply that smooth muscle bladder strips exhibit similar muscle properties and history-dependent behaviour compared to striated muscles. The provided dataset of muscle properties is important for bladder modelling as well as for the analyses and interpretation of dynamic bladder filling and voiding.

  14. A laserterapia de baixa potência melhora o desempenho muscular mensurado por dinamometria isocinética em humanos Low-level laser therapy enhances muscular performance as measured by isokinetic dynamometry in humans

    Directory of Open Access Journals (Sweden)

    Ernesto Cesar Pinto Leal Junior

    2010-12-01

    Full Text Available A fadiga muscular é uma nova área de pesquisa em laserterapia, com poucos estudos conduzidos. Embora a laserterapia de baixa potência (LBP previamente ao exercício tenha apresentado resultados positivos no retardo da fadiga musculoesquelética, ainda não foi estudada utilizando-se a dinamometria isocinética para mensurar desempenho e fadiga muscular. Este estudo tem o objetivo de avaliar os efeitos da LBP (655 nm, 50 mW, 2,4 J por ponto e 12 J de energia total sobre o desempenho e fadiga muscular do músculo tibial anterior, utilizando dinamometria isocinética (30 repetições de contração concêntrica em 14 indivíduos saudáveis sedentários do sexo masculino. Os voluntários foram avaliados ao efetuar 30 repetições isocinéticas de dorsiflexão de tornozelo à velocidade angular de 240°.seg-1. Os resultados mostram que, quando os voluntários foram tratados com LBP antes do exercício, os valores do pico de torque (30,91±5,86 N.m foram significativamente superiores, comparados a três medições anteriores sem a aplicação de LBP (24,92±7,45 N.m, pSkeletal muscle fatigue is a novel research area in laser therapy, there being few studies carried out. Though low-level laser therapy (LLLT applied prior to exercise has showed positive results in delaying skeletal muscle fatigue, no studies could be found that measured muscle performance and fatigue by means of isokinetic dynamometry. This clinical trial aims at assessing the effects of LLLT (655 nm, 50 mW and 12 J total energy delivered on anterior tibialis muscle performance and fatigue by means of isokinetic dynamometry (30 concentric-mode repetitions at 240º.sec-1 angular speed in 14 healthy male subjects. Results show that, when volunteers had been treated with LLLT prior to exercise, torque peak values (30.91±5.86 N.m were significantly higher than those of three previous measurements with no LLLT (24.92±7.45 N.m, p<0.001; 26.83±7.74 N.m, p<0.01; and 26.00±7.88 N.m, p<0

  15. The Relationship of Temperature to Strength and Power Production in Intact Human Skeletal Muscle.

    Science.gov (United States)

    1979-06-01

    newton- meters (Nm). The use of the Cybex II isokinetic device has been similarly described by Thorstensson et al. (1976). The peak torque value, or the... isokinetic testing device at four lever arm speeds (0,60,180 and 300*/sec).Maximal knee exter- sions at the different lever arm speeds were evaluated for...Each subject was tested on the Cybex II isokinetic testing device at four lever arm speeds (0,60,180 and $Osec).Maximal knee exten- sions at the

  16. Eccentric Torque-Producing Capacity is Influenced by Muscle Length in Older Healthy Adults.

    Science.gov (United States)

    Melo, Ruth C; Takahashi, Anielle C M; Quitério, Robison J; Salvini, Tânia F; Catai, Aparecida M

    2016-01-01

    Considering the importance of muscle strength to functional capacity in the elderly, the study investigated the effects of age on isokinetic performance and torque production as a function of muscle length. Eleven younger (24.2 ± 2.9 years) and 16 older men (62.7 ± 2.5 years) were subjected to concentric and eccentric isokinetic knee extension/flexion at 60 and 120° · s(-1) through a functional range of motion. The older group presented lower peak torque (in newton-meters) than the young group for both isokinetic contraction types (age effect, p torque deficits in the older group were near 30 and 29% for concentric and eccentric contraction, respectively. Concentric peak torque was lower at 120° · s(-1) than at 60° · s(-1) for both groups (angular velocity effect, p torque was the only exercise tested that showed an interaction effect between age and muscle length (p torque responses to the muscle length between groups. Compared with the young group, the eccentric knee extension torque was 22-56% lower in the older group, with the deficits being lower in the shortened muscle length (22-27%) and higher (33-56%) in the stretched muscle length. In older men, the production of eccentric knee strength seems to be dependent on the muscle length. At more stretched positions, older subjects lose the capacity to generate eccentric knee extension torque. More studies are needed to assess the mechanisms involved in eccentric strength preservation with aging and its relationship with muscle length.

  17. Motor performance during and following acute alcohol intoxication in healthy non-alcoholic subjects

    DEFF Research Database (Denmark)

    Poulsen, Mette Buch; Jakobsen, Johannes Klitgaard; Andersen, Henning

    2007-01-01

    Chronic alcohol abuse has adverse effects on skeletal muscle, and reduced muscle strength is frequently seen in chronic alcoholics. In this study the acute effects of moderate alcohol intoxication on motor performance was evaluated in 19 non-alcoholic healthy subjects (10 women, 9 men......). A randomised double-blinded placebo controlled design was applied to subjects receiving alcohol in juice and pure juice at two separate test periods. Isokinetic and isometric muscle strength and endurance were determined before, during, 24 and 48 h after the ingestion of alcohol in juice and juice (placebo......). To detect a reduced activation of the central motor pathways superimposed external electrical stimulations during voluntary contractions were applied. Creatine kinase (CK) was measured to detect any alcohol-induced changes in sarcolemmal integrity. No change was seen in isokinetic as well as in isometric...

  18. 3D strength surfaces for ankle plantar- and dorsi-flexion in healthy adults: an isometric and isokinetic dynamometry study

    Directory of Open Access Journals (Sweden)

    Sara J. Hussain

    2016-11-01

    Full Text Available Abstract Background The ankle is an important component of the human kinetic chain, and deficits in ankle strength can negatively impact functional tasks such as balance and gait. While peak torque is influenced by joint angle and movement velocity, ankle strength is typically reported for a single angle or movement speed. To better identify deficits and track recovery of ankle strength after injury or surgical intervention, ankle strength across a range of movement velocities and joint angles in healthy adults is needed. Thus, the primary goals of this study were to generate a database of strength values and 3-dimensional strength surface models for plantarflexion (PF and dorsiflexion (DF ankle strength in healthy men and women. Secondary goals were to develop a means to estimate ankle strength percentiles as well as examine predictors of maximal ankle strength in healthy adults. Methods Using an isokinetic dynamometer, we tested PF and DF peak torques at five joint angles (−10° [DF], 0° [neutral], 10° [PF], 20° [PF] and 30° [PF] and six velocities (0°/s, 30°/s, 60°/s, 90°/s, 120°/s and 180°/s in 53 healthy adults. These data were used to generate 3D plots, or “strength surfaces”, for males and females for each direction; surfaces were fit using a logistic equation. We also tested predictors of ankle strength, including height, weight, sex, and self-reported physical activity levels. Results Torque-velocity and torque-angle relationships at the ankle interact, indicating that these relationships are interdependent and best modeled using 3D surfaces. Sex was the strongest predictor of ankle strength over height, weight, and self-reported physical activity levels. 79 to 97 % of the variance in mean peak torque was explained by joint angle and movement velocity using logistic equations, for men and women and PF and DF directions separately. Conclusions The 3D strength data and surface models provide a more comprehensive dataset

  19. 3D strength surfaces for ankle plantar- and dorsi-flexion in healthy adults: an isometric and isokinetic dynamometry study.

    Science.gov (United States)

    Hussain, Sara J; Frey-Law, Laura

    2016-01-01

    The ankle is an important component of the human kinetic chain, and deficits in ankle strength can negatively impact functional tasks such as balance and gait. While peak torque is influenced by joint angle and movement velocity, ankle strength is typically reported for a single angle or movement speed. To better identify deficits and track recovery of ankle strength after injury or surgical intervention, ankle strength across a range of movement velocities and joint angles in healthy adults is needed. Thus, the primary goals of this study were to generate a database of strength values and 3-dimensional strength surface models for plantarflexion (PF) and dorsiflexion (DF) ankle strength in healthy men and women. Secondary goals were to develop a means to estimate ankle strength percentiles as well as examine predictors of maximal ankle strength in healthy adults. Using an isokinetic dynamometer, we tested PF and DF peak torques at five joint angles (-10° [DF], 0° [neutral], 10° [PF], 20° [PF] and 30° [PF]) and six velocities (0°/s, 30°/s, 60°/s, 90°/s, 120°/s and 180°/s) in 53 healthy adults. These data were used to generate 3D plots, or "strength surfaces", for males and females for each direction; surfaces were fit using a logistic equation. We also tested predictors of ankle strength, including height, weight, sex, and self-reported physical activity levels. Torque-velocity and torque-angle relationships at the ankle interact, indicating that these relationships are interdependent and best modeled using 3D surfaces. Sex was the strongest predictor of ankle strength over height, weight, and self-reported physical activity levels. 79 to 97 % of the variance in mean peak torque was explained by joint angle and movement velocity using logistic equations, for men and women and PF and DF directions separately. The 3D strength data and surface models provide a more comprehensive dataset of ankle strength in healthy adults than previously reported. These

  20. Evaluación isocinética de los músculos de la rodilla en jugadores de fútbol : Análisis discriminante

    NARCIS (Netherlands)

    Mazuquin, Bruno Fles; Pereira, Ligia Maxwell; Dias, Josilainne Marcelino; Batista, João Pedro; Silva, Mônica Angélica Cardoso; Finatti, Matheus Elmer; Leme, Lucas Carvalho; Carregaro, Rodrigo Luiz; Moura, Felipe Arruda; Cardoso, Jefferson Rosa

    2015-01-01

    Introduction: Muscle activity in soccer players can be measured by isokinetic dynamometer, which is a reliable tool for assessing human performance. Objectives: To perform isokinetic analyses and to determine which variables differentiate the under-17 (U17) soccer category from the professional

  1. Evaluation of the Combined Application of Neuromuscular Electrical Stimulation and Volitional Contractions on Thigh Muscle Strength, Knee Pain and Physical Performance in Women at Risk for Knee Osteoarthritis: A Randomized Controlled Trial.

    Science.gov (United States)

    Rabe, Kaitlin G; Matsuse, Hiroo; Jackson, Anthony; Segal, Neil A

    2018-05-28

    Knee osteoarthritis (OA) is a leading cause of disability that is associated with quadriceps weakness. However, strengthening in people with or with risk factors for knee OA can be poorly tolerated. To assess the efficacy of a twelve-week low-load exercise program, using a hybrid training system (HTS) that utilizes the combination of neuromuscular electrical stimulation and volitional contractions, for improving thigh muscle strength, knee pain and physical performance in women with or with risk factors for knee OA. Randomized, single-blind, controlled trial SETTING: Exercise training laboratory PARTICIPANTS: Forty-two women, age 44-85 years, with risk factors for knee OA INTERVENTIONS: Participants randomized to 12 weeks of biweekly low-load resistance training either with HTS or on an isokinetic dynamometer (control). Maximum isokinetic knee extensor torque. Secondary measures included: maximum isokinetic knee flexor torque, knee pain (KOOS), and timed 20-meter walk and chair-stand tests. HTS and control both resulted in muscle strengthening, reduced knee pain and improved physical performance. HTS group quadriceps and hamstring strength increased by 0.06±0.04 Nm/kg (p>.05) and 0.05±0.02 Nm/kg (p=.02), respectively. Control group quadriceps and hamstring strength increased by 0.03±0.04 Nm/kg (p>.05) and 0.06±0.02 Nm/kg (p=.009), respectively. Knee pain improved by 11.9±11.5 points (pmeter walk time decreased by 1.60±2.04 seconds (p=.005) and 0.95±1.2 seconds (p=.004), and chair stand time decreased by 4.8±10.0 seconds (p>.05) and 1.9±4.7 seconds (p>.05) in the HTS and control groups, respectively. These results did not differ statistically between HTS and control groups. These results suggest HTS is effective for improving pain and physical performance in women with risk factors for knee OA. However, HTS does not appear to be superior to low-load resistance training for improving muscle strength, pain or physical function. Copyright © 2018 American

  2. Sex differences in neuromuscular function after repeated eccentric contractions of the knee extensor muscles.

    Science.gov (United States)

    Lee, Andrea; Baxter, Jake; Eischer, Claire; Gage, Matt; Hunter, Sandra; Yoon, Tejin

    2017-06-01

    This study examined the mechanisms for force and power reduction during and up to 48 h after maximal eccentric contractions of the knee extensor muscles in young men and women. 13 men (22.8 ± 2.6 years) and 13 women (21.6 ± 2.2 years) performed 150 maximal effort eccentric contractions (5 sets of 30) with the knee extensor muscles at 60° s -1 . Maximal voluntary isometric contractions (MVIC) and maximal voluntary concentric contractions (MVCC) were performed before and after the 150 eccentric contractions. The MVCCs involved a set of two isokinetic contractions at 60° s -1 and sets of isotonic contractions performed at seven different resistance loads (1 N m, 10, 20, 30, 40, 50, and 60% MVIC). Electrical stimulation was used during the MVICs and at rest to determine changes in voluntary activation and contractile properties. At baseline, men were stronger than women (MVIC: 276 ± 48 vs. 133 ± 37 N m) and more powerful (MVCC: 649 ± 77 vs. 346 ± 78 W). At termination of the eccentric contractions, voluntary activation, resting twitch amplitude, and peak power during concentric contractions at the seven loads and at 60° s -1 decreased (P  0.05) with no sex differences. Central mechanisms were primarily responsible for the depressed maximal force production up to 48 h after repeated eccentric contractions of the knee extensors and these mechanisms were similar in men and women.

  3. Avaliação isocinética de 18 pacientes do sexo masculino submetidos à correção cirúrgica da luxação acromioclavicular aguda com seguimento mínimo de dois anos Isokinetic evaluation of eighteen male patients submitted to surgical corretion of acute acromioclavicular luxation with a minimum two-year follow-up

    Directory of Open Access Journals (Sweden)

    Flavio Almeida Salles

    2002-06-01

    Full Text Available Foram estudados 18 pacientes submetidos ao tratamento cirúrgico de luxação acromioclavicular aguda do grau III da classificação de ALLMAN-TOSSY, todos do sexo masculino com idade média de 36 anos, foram avaliados sob o ponto de vista isocinético com tempo de evolução variando de 24 até 127 meses. A avaliação isocinética foi realizada através de um dinamômetro computadorizado marca CYBEX® modelo 6000 na velocidade angular de 60º/segundo e demonstrou resultados significantes no movimento de abdução no plano neutro, com déficit no pico de torque do lado operado, quando comparado com o lado contra-lateral. Quando comparados os ombros com e sem subluxação, os com subluxação demonstraram défcit no trabalho total tanto na adução quanto na abdução no plano neutro.Eighteen male patients, mean age 36 years, submitted to surgical treatment of ALLMAN-TOSSY grade III acute acromioclavicular luxation were studied. They were isokinetically evaluated during an evolution period ranging from 24 to 127 months. The isokinetic evaluation was carried out with a Cybex® 6000 computerized dynamometer, at a 60º/s angular speed, showing significant results in vertical abduction, with a deficit in peak torque in the operated on shoulder as compared to the contralateral side. When the groups with and without subluxation were compared a deficit in total work was observed in the group with subluxation both in adduction and abduction.

  4. The effects of electromyostimulation training and basketball practice on muscle strength and jumping ability.

    Science.gov (United States)

    Maffiuletti, N A; Cometti, G; Amiridis, I G; Martin, A; Pousson, M; Chatard, J C

    2000-08-01

    The aim of this study was to investigate the influence of a 4-week electromyostimulation training program on the strength of the knee extensors and the vertical jump performance of 10 basketball players. Electromyostimulation sessions were carried out 3 times weekly; each session consisted of 48 contractions. Testing was carried out before and after the electromyostimulation training program (week 4) and once more after 4 weeks of normal basketball training (week 8). At week 4, isokinetic strength increased significantly (p training increased also isometric strength at the two angles adjacent to the training angle (p jump increased significantly by 14% at week 4 (p jump showed no change. At week 8, gains in isokinetic, isometric strength and squat-jump performance were maintained and the counter movement jump performance increased significantly by 17% (ptraining program enhanced knee extensor strength and squat jump performance of basketball players.

  5. Comparing electro- and mechano-myographic muscle activation patterns in self-paced pediatric gait.

    Science.gov (United States)

    Plewa, Katherine; Samadani, Ali; Chau, Tom

    2017-10-01

    Electromyography (EMG) is the standard modality for measuring muscle activity. However, the convenience and availability of low-cost accelerometer-based wearables makes mechanomyography (MMG) an increasingly attractive alternative modality for clinical applications. Literature to date has demonstrated a strong association between EMG and MMG temporal alignment in isometric and isokinetic contractions. However, the EMG-MMG relationship has not been studied in gait. In this study, the concurrence of EMG- and MMG-detected contractions in the tibialis anterior, lateral gastrocnemius, vastus lateralis, and biceps femoris muscles were investigated in children during self-paced gait. Furthermore, the distribution of signal power over the gait cycle was statistically compared between EMG-MMG modalities. With EMG as the reference, muscular contractions were detected based on MMG with balanced accuracies between 88 and 94% for all muscles except the gastrocnemius. MMG signal power differed from that of EMG during certain phases of the gait cycle in all muscles except the biceps femoris. These timing and power distribution differences between the two modalities may in part be related to muscle fascicle length changes that are unique to muscle motion during gait. Our findings suggest that the relationship between EMG and MMG appears to be more complex during gait than in isometric and isokinetic contractions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Pain severity is associated with muscle strength and peak oxygen uptake in adults with fibromyalgia

    Directory of Open Access Journals (Sweden)

    Hooten WM

    2014-05-01

    Full Text Available W Michael Hooten,1,2 Jolene M Smith,3 Jason S Eldrige,1 David A Olsen,3 W David Mauck,1 Susan M Moeschler11Department of Anesthesiology, 2Department of Psychiatry and Psychology, Mayo Clinic College of Medicine, 3Mayo School of Graduate Medical Education, Rochester, MN, USABackground: The associations between pain, lower extremity strength, and aerobic conditioning have not been widely investigated in adults with fibromyalgia (FM. The principle objective of this study was to investigate the relationship between pain severity and knee strength in patients seeking treatment for FM. A secondary objective was to investigate the relationship between pain scores and aerobic conditioning.Methods: Three measures of knee strength (isokinetic extensor, isokinetic flexor, isometric extensor were quantified in the dominant leg of 69 adults with FM using a dynamometer at speeds of 60 degrees per second (60°/s and 180°/s. Peak oxygen uptake (VO2 was assessed using a cycle ergometer, and pain was assessed using the pain severity subscale of the Multidimensional Pain Inventory.Results: In univariable linear regression analyses using pain severity as the dependent variable, lesser values of isokinetic knee extensor strength at 60°/s (P=0.041 and 180°/s (P=0.010, isokinetic knee flexor strength at 60°/s (P=0.028 and 180°/s (P=0.003, and peak VO2 uptake (P=0.031 were predictive of greater pain severity scores. In multiple variable linear regression models adjusted for age, sex, body mass index, and opioid use, the following associations retained statistical significance; isokinetic knee extensor strength at 60°/s (P=0.020 and 180°/s (P=0.003, isokinetic knee flexor strength at 60°/s (P=0.015 and 180°/s (P=0.001, and peak VO2 uptake (P=0.014. However, no significant associations were found between pain severity and isometric knee extensor strength.Conclusion: The main findings from this study were that lesser values of isokinetic knee strength and peak VO

  7. Sex Comparisons for Relative Peak Torque and Electromyographic Mean Frequency during Fatigue

    Science.gov (United States)

    Stock, Matt S.; Beck, Travis W.; DeFreitas, Jason M.; Ye, Xin

    2013-01-01

    Purpose: This study compared the relative peak torque and normalized electromyographic (EMG) mean frequency (MNF) responses during fatiguing isokinetic muscle actions for men versus women. Method: Twenty men M[subscript age] ± SD = 22 ± 2 years) and 20 women M[subscript age] ± SD = 22 ± 1 years) performed 50 maximal concentric isokinetic muscle…

  8. Artificial neural networks in knee injury risk evaluation among professional football players

    Science.gov (United States)

    Martyna, Michałowska; Tomasz, Walczak; Krzysztof, Grabski Jakub; Monika, Grygorowicz

    2018-01-01

    Lower limb injury risk assessment was proposed, based on isokinetic examination that is a part of standard athlete's biomechanical evaluation performed mainly twice a year. Information about non-contact knee injury (or lack of the injury) sustained within twelve months after isokinetic test, confirmed in USG were verified. Three the most common types of football injuries were taken into consideration: anterior cruciate ligament (ACL) rupture, hamstring and quadriceps muscles injuries. 22 parameters, obtained from isokinetic tests were divided into 4 groups and used as input parameters of five feedforward artificial neural networks (ANNs). The 5th group consisted of all considered parameters. The networks were trained with the use of Levenberg-Marquardt backpropagation algorithm to return value close to 1 for the sets of parameters corresponding injury event and close to 0 for parameters with no injury recorded within 6 - 12 months after isokinetic test. Results of this study shows that ANN might be useful tools, which simplify process of simultaneous interpretation of many numerical parameters, but the most important factor that significantly influence the results is database used for ANN training.

  9. Effects of Fuel Specification and Additives on Soot Formation.

    Science.gov (United States)

    1983-12-01

    17 3 Isokinetic Sampling ..................................... 17 C. 4 Chemical Strlture of Amberlite XAD-20...drawbacksof rake probes is their inability to provide spatial differentiation and, unless very sophisticated, isokinetic sampling across the entire flow...is quite effective but necessitates more complex probes and metering systems, and care must be taken to prevent any undesirable reactions or effects

  10. 40 CFR Appendix M to Part 51 - Recommended Test Methods for State Implementation Plans

    Science.gov (United States)

    2010-07-01

    ... greater than PM10, and an in-stack glass fiber filter is used to collect the PM10. To maintain isokinetic...., should be available to allow isokinetic sampling to be conducted over a range of flow rates. Calibrate... and power leads of sufficient length to connect probe to meter and flow control console. 2.1.8 Vacuum...

  11. Shoulder Rotator Muscle Dynamometry Characteristics: Side Asymmetry and Correlations with Ball-Throwing Speed in Adolescent Handball Players

    Science.gov (United States)

    Pontaga, Inese; Zidens, Janis

    2014-01-01

    The aim of the investigation was to: 1) compare shoulder external/internal rotator muscles’ peak torques and average power values and their ratios in the dominant and non-dominant arm; 2) determine correlations between shoulder rotator muscles’ peak torques, average power and ball-throwing speed in handball players. Fourteen 14 to 15-year-old male athletes with injury-free shoulders participated in the study (body height: 176 ± 7 cm, body mass 63 ± 9 kg). The tests were carried out by an isokinetic dynamometer system in the shoulder internal and external rotation movements at angular velocities of 60°/s, 90°/s and 240°/s during concentric contractions. The eccentric external– concentric internal rotator muscle contractions were performed at the velocity of 90°/s. The player threw a ball at maximal speed keeping both feet on the floor. The speed was recorded with reflected light rays. Training in handball does not cause significant side asymmetry in shoulder external/internal rotator muscle peak torques or the average power ratio. Positive correlations between isokinetic characteristics of the shoulder internal and external rotator muscles and ball-throwing speed were determined. The power produced by internal rotator muscles during concentric contractions after eccentric contractions of external rotator muscles was significantly greater in the dominant than in the non-dominant arm. Thus, it may be concluded that the shoulder eccentric external/concentric internal rotator muscle power ratio is significantly greater than this ratio in the concentric contractions of these muscles. PMID:25414738

  12. Shoulder Rotator Muscle Dynamometry Characteristics: Side Asymmetry and Correlations with Ball-Throwing Speed in Adolescent Handball Players

    Directory of Open Access Journals (Sweden)

    Pontaga Inese

    2014-10-01

    Full Text Available The aim of the investigation was to: 1 compare shoulder external/internal rotator muscles’ peak torques and average power values and their ratios in the dominant and non-dominant arm; 2 determine correlations between shoulder rotator muscles’ peak torques, average power and ball-throwing speed in handball players. Fourteen 14 to 15- year-old male athletes with injury-free shoulders participated in the study (body height: 176 ± 7 cm, body mass 63 ± 9 kg. The tests were carried out by an isokinetic dynamometer system in the shoulder internal and external rotation movements at angular velocities of 60°/s, 90°/s and 240°/s during concentric contractions. The eccentric external- concentric internal rotator muscle contractions were performed at the velocity of 90°/s. The player threw a ball at maximal speed keeping both feet on the floor. The speed was recorded with reflected light rays. Training in handball does not cause significant side asymmetry in shoulder external/internal rotator muscle peak torques or the average power ratio. Positive correlations between isokinetic characteristics of the shoulder internal and external rotator muscles and ball-throwing speed were determined. The power produced by internal rotator muscles during concentric contractions after eccentric contractions of external rotator muscles was significantly greater in the dominant than in the non-dominant arm. Thus, it may be concluded that the shoulder eccentric external/concentric internal rotator muscle power ratio is significantly greater than this ratio in the concentric contractions of these muscles

  13. The Potential Risk Factors Relevant to Lateral Epicondylitis by Wrist Coupling Posture.

    Directory of Open Access Journals (Sweden)

    Su-Ya Lee

    Full Text Available The use of awkward wrist postures and unskilled techniques might induce lateral epicondylitis. This study thus investigated the effects of wrist deviation combined with extension and movement velocity on the dynamic performances of the wrist muscles during the coupling posture via a custom-made bi-planar isokinetic dynamometer. Thirty subjects were recruited to perform the isokinetic testing. We measured the muscle strengths and activities for the wrist extensors and flexors during concentric and eccentric contractions at three movement velocities, 30°s-1, 90°s-1, and 180°s-1, combined with three wrist postures, neutral position (NP, radial deviation (RD, and ulnar deviation (UD. The root mean square (RMS of the electromyographic signal in the extensor digitorum communis (EDC, normalized peak torque of extensors, and ratio of normalized peak torque between wrist extensors and flexors, were all greater in the NP than RD and UD in both contractions. The ratio of RMS between EDC and flexor digitorum superficialis (FDS had a significantly greater value in RD than UD during the concentric contraction. The EDC showed significantly higher activity at the fast velocity in both contractions. Nevertheless, a significantly higher RMS of the electromyographic signal between EDC and FDS and the ratio of strength between wrist extensors and flexors were found at slow velocity in both contractions. The wrist deviation combined with extension and movement velocity of the wrist joint should thus be considered as influential factors which might alter the dynamic performances, and may result in further injury of the elbow joint.

  14. Systemic inflammatory responses to maximal versus submaximal lengthening contractions of the elbow flexors.

    Science.gov (United States)

    Peake, Jonathan M; Nosaka, Kazunori; Muthalib, Makii; Suzuki, Katsuhiko

    2006-01-01

    We compared changes in markers of muscle damage and systemic inflammation after submaximal and maximal lengthening muscle contractions of the elbow flexors. Using a cross-over design, 10 healthy young men not involved in resistance training completed a submaximal trial (10 sets of 60 lengthening contractions at 10% maximum isometric strength, 1 min rest between sets), followed by a maximal trial (10 sets of three lengthening contractions at 100% maximum isometric strength, 3 min rest between sets). Lengthening contractions were performed on an isokinetic dynamometer. Opposite arms were used for the submaximal and maximal trials, and the trials were separated by a minimum of two weeks. Blood was sampled before, immediately after, 1 h, 3 h, and 1-4 d after each trial. Total leukocyte and neutrophil numbers, and the serum concentration of soluble tumor necrosis factor-alpha receptor 1 were elevated after both trials (P < 0.01), but there were no differences between the trials. Serum IL-6 concentration was elevated 3 h after the submaximal contractions (P < 0.01). The concentrations of serum tumor necrosis factor-alpha, IL-1 receptor antagonist, IL-10, granulocyte-colony stimulating factor and plasma C-reactive protein remained unchanged following both trials. Maximum isometric strength and range of motion decreased significantly (P < 0.001) after both trials, and were lower from 1-4 days after the maximal contractions compared to the submaximal contractions. Plasma myoglobin concentration and creatine kinase activity, muscle soreness and upper arm circumference all increased after both trials (P < 0.01), but were not significantly different between the trials. Therefore, there were no differences in markers of systemic inflammation, despite evidence of greater muscle damage following maximal versus submaximal lengthening contractions of the elbow flexors.

  15. Eccentric training for shoulder abductors improves pain, function and isokinetic performance in subjects with shoulder impingement syndrome: a case series Treino excêntrico para abdutores do ombro melhora dor, função e desempenho isocinético em sujeitos com síndrome do impacto: série de casos

    Directory of Open Access Journals (Sweden)

    Paula R. Camargo

    2012-02-01

    Full Text Available BACKGROUND: Conservative treatments have been proposed for people with shoulder impingement syndrome (SIS, such as strengthening of the rotator cuff and scapular muscles and stretching of the soft tissues of the shoulder. However, there is a lack of studies analyzing the effectiveness of eccentric training in the treatment of SIS. OBJECTIVES: To evaluate the effects of eccentric training for shoulder abductors on pain, function, and isokinetic performance during concentric and eccentric abduction of the shoulder in subjects with SIS. METHODS: Twenty subjects (7 females, 34.2 SD 10.2 years, 1.7 SD 0.1 m, 78.0 SD 16.3 kg with unilateral SIS completed the study protocol. Bilateral isokinetic eccentric training at 60º/s for shoulder abductors was performed for six consecutive weeks, twice a week, on alternate days. For each training day, three sets of 10 repetitions were performed with a 3-minute rest period between the sets for each side. The range of motion trained was 60° (ranging from 80° to 20°. The Disabilities of the Arm, Shoulder and Hand (DASH questionnaire was used to evaluate functional status and symptoms of the upper limbs. Peak torque, total work and acceleration time were measured during concentric and eccentric abduction of the arm at 60º/s and 180º/s using an isokinetic dynamometer. RESULTS: DASH scores, peak torque, total work and acceleration time improved (pCONTEXTUALIZAÇÃO: Tratamentos conservadores têm sido propostos para pessoas com síndrome do impacto (SI do ombro, como fortalecimento do manguito rotador e dos músculos escapulares e alongamento dos tecidos moles do ombro. No entanto, são escassos os estudos que analisaram a eficácia do treinamento excêntrico no tratamento da SI. OBJETIVOS: Avaliar os efeitos do treinamento excêntrico para abdutores do ombro na dor, função e desempenho isocinético durante a abdução concêntrica e excêntrica do ombro em indivíduos com SI. MÉTODOS: Vinte indivíduos (sete

  16. Respirator Filter Efficiency Testing Against Particulate and Biological Aerosols Under Moderate to High Flow Rates

    Science.gov (United States)

    2006-08-01

    flow rate through the test filter. The flow rate was measured using a mass flow meter (Series 4000, TSI, Shoreview, MN). Several modifications were made...operating conditions. This included assessing the effect of non- isokinetic sampling, flow calibrations, and characterization of the challenge...sampling bias on the measured penetrations due to the non- isokinetic sampling downstream. 3.3.2.2 System Characterization. Shakedown tests were

  17. Early changes in muscle strength after total knee arthroplasty. A 6-month follow-up of 30 knees

    DEFF Research Database (Denmark)

    Lorentzen, J S; Petersen, M M; Brot, C

    1999-01-01

    to surgery, and after 3 and 6 months, isokinetic and isometric muscle strength in both legs were measured, using a Cybex 6000 dynamometer. Isokinetic tests showed a bilateral, significant, and progressive increase (30-53%) in flexor muscle strength most pronounced in the operated legs. Isokinetic extensor...... strength increased significantly (14-18%) in the operated legs, while in the contralateral legs, a limited increase was found. Isometric flexion strength significantly decreased in the operated knees (17%). Isometric extension strength showed a temporary decrease at 3 months, which returned...... to the preoperative level. No significant change in isometric strength was observed in the contralateral legs. The knee pain during the muscle strength measurements decreased significantly from the preoperative level, which may indicate that the substantial pain relief within 3 months after a TKA is an important...

  18. Discussion about different cut-off values of conventional hamstring-to-quadriceps ratio used in hamstring injury prediction among professional male football players.

    Directory of Open Access Journals (Sweden)

    Monika Grygorowicz

    Full Text Available To measure the sensitivity and specificity of differences cut-off values for isokinetic Hcon/Qcon ratio in order to improve the capacity to evaluate (retrospectively the injury of hamstring muscles in professional soccer screened with knee isokinetic tests.Retrospective study.Medical and biomechanical data of professional football players playing for the same team for at least one season between 2010 and 2016 were analysed. Hamstring strain injury cases and the reports generated via isokinetic testing were investigated. Isokinetic concentric(con hamstring(H and quadriceps(Q absolute strength in addition with Hcon/Qcon ratio were examined for the injured versus uninjured limbs among injured players, and for the injured and non-injured players. 2 x 2 contingency table was used for comparing variables: predicted injured or predicted uninjured with actual injured or actual uninjured. Sensitivity, specificity, accuracy, positive and negative predictive values, and positive and negative likelihood ratio were calculated for three different cut-off values (0.47 vs. 0.6 vs. 0.658 to compare the discriminative power of an isokinetic test, whilst examining the key value of Hcon/Qcon ratio which may indicate the highest level of ability to predispose a player to injury. McNemar's chi2 test with Yates's correction was used to determine agreement between the tests. PQStat software was used for all statistical analysis, and an alpha level of p <0.05 was used for all statistical comparisons.340 isokinetic test reports on both limbs of 66 professional soccer players were analysed. Eleven players suffered hamstring injuries during the analysed period. None of these players sustained recurrence of hamstring injury. One player sustained hamstring strain injury on both legs, thus the total number of injuries was 12. Application of different cut-off values for Hcon/Qcon significantly affected the sensitivity and specificity of isokinetic test used as a tool for

  19. Development of a Biofeedback Therapeutic Exercise Supporting Manipulator for Lower Limbs

    Science.gov (United States)

    Hashimoto, Yosuke; Hisada, Takashi; Komada, Satoshi; Hirai, Junji

    Although equipments that support physical therapy have been developed, there are few types of equipment to improve quality of physical therapy. This paper proposes a new concept of robotic biofeedback exercise equipment that displays human muscle force during training. The concept tries to have therapeutic value through grasping of condition for trainee during exercise and giving an incentive to perform training. The equipment is not only for convalescent patients but also for athletes and healthy persons with a physical trouble. The manipulator is designed to support lower limb rehabilitation of knee and hip joints in sagittal plane, where a 3-degrees-of-freedom manipulator is adopted in order to realize low height equipment. Since the manipulator has redundant degree of freedom, collision avoidance is performed by a controller based on acceleration control by disturbance observer. Moreover, simultaneous isokinetic movement for knee and hip joints that has an adjustment capability of maximum speed and time constant is realized in order to perform safe training by isokinetic muscular contraction. Desired motion is realized experimentally by the proposed manipulator.

  20. Avaliação isocinética em atletas paraolímpicos Isokinetic evaluation in paralympic athletes

    Directory of Open Access Journals (Sweden)

    Antônio Carlos Silva

    2002-06-01

    Full Text Available O equilíbrio dos parâmetros de força muscular nas articulações é de grande relevância, tanto no aspecto clínico como para o desempenho atlético. Informações sobre os valores desses parâmetros em atletas olímpicos e principalmente nos paraolímpicos são raras. Neste trabalho apresentamos os resultados da avaliação muscular isocinética (Cybex 6000 realizada na equipe brasileira que participou dos Jogos Paraolímpicos de Sidney 2000. Foram avaliados os músculos flexores e extensores dos joelhos de 11 jogadores de futebol (paralisia cerebral, idade 24,6 ± 4,8 anos; peso 67 ± 5,5kg; altura 177,7 ± 3,8cm e 12 de basquetebol (deficientes mentais, idade 24,7 ± 4,4 anos; peso 76,6 ± 13,4kg; altura 184,4 ± 10cm, e os músculos rotadores internos e rotadores externos de ombros de seis judocas (deficientes visuais, idade 29,8 ± 5,6 anos; peso 87 ± 21,6kg; altura 171,5 ± 6,9cm. Os jogadores de futebol apresentaram relação de equilíbrio muscular entre flexores e extensores de joelhos dentro dos parâmetros de normalidade apesar da fraqueza muscular imposta pela paralisia cerebral. Nos judocas o equilíbrio muscular entre rotadores externos e rotadores internos mostrou-se dentro dos limites de normalidade. A principal característica dos jogadores de basquetebol foi o valor de pico de torque próximo do esperado para indivíduos hígidos não atletas. Os valores numéricos estão apresentados no texto para serem usados como referência para profissionais da área.The balance between agonist and antagonist muscles in the joints is of great relevance to clinical practice and to sports performance. Information about these parameters amongst Olympic and especially Paralympic athletes is scarce. The purpose of this study was to present the results of the isokinetic evaluation (Cybex 6000 of the Brazilian team that participated in the Sydney Paralympic Games. The flexor and extensor muscles of the knee were evaluated in 11 soccer

  1. Injury Prevention and Performance Enhancement in 101st Airborne Soldiers

    Science.gov (United States)

    2009-10-01

    assessments consisting of strength, cardiorespiratory, anaerobic, and body composition tests. Isokinetic strength testing 10 was performed on the...a meter or more. Moreover, the maximum VGRF experienced during landing tasks performed in the field could be much greater than the standardized... isokinetic strength. Subjects were assigned to groups based on the DoD’s standard for body fat (Group 1: ≤18% BF; Group 2 >18% BF). Soldiers who met

  2. Effects of isokinetic passive exercise and isometric muscle contraction on passive stiffness

    OpenAIRE

    寺田, 茂; Terada, Shigeru

    2013-01-01

    博士論文要旨Abstract 要約Outline 以下に掲載:Journal of Physical Therapy Science 25(10) pp.1347-1352. The Society of Physical Therapy Science. 共著者:Shigeru Terada, Hiroichi Miaki, Keita Uchiyama, Shozo Hayakawa, Toshiaki Yamazaki

  3. Olympic weightlifting and plyometric training with children provides similar or greater performance improvements than traditional resistance training.

    Science.gov (United States)

    Chaouachi, Anis; Hammami, Raouf; Kaabi, Sofiene; Chamari, Karim; Drinkwater, Eric J; Behm, David G

    2014-06-01

    A number of organizations recommend that advanced resistance training (RT) techniques can be implemented with children. The objective of this study was to evaluate the effectiveness of Olympic-style weightlifting (OWL), plyometrics, and traditional RT programs with children. Sixty-three children (10-12 years) were randomly allocated to a 12-week control OWL, plyometric, or traditional RT program. Pre- and post-training tests included body mass index (BMI), sum of skinfolds, countermovement jump (CMJ), horizontal jump, balance, 5- and 20-m sprint times, isokinetic force and power at 60 and 300° · s(-1). Magnitude-based inferences were used to analyze the likelihood of an effect having a standardized (Cohen's) effect size exceeding 0.20. All interventions were generally superior to the control group. Olympic weightlifting was >80% likely to provide substantially better improvements than plyometric training for CMJ, horizontal jump, and 5- and 20-m sprint times, whereas >75% likely to substantially exceed traditional RT for balance and isokinetic power at 300° · s(-1). Plyometric training was >78% likely to elicit substantially better training adaptations than traditional RT for balance, isokinetic force at 60 and 300° · s(-1), isokinetic power at 300° · s(-1), and 5- and 20-m sprints. Traditional RT only exceeded plyometric training for BMI and isokinetic power at 60° · s(-1). Hence, OWL and plyometrics can provide similar or greater performance adaptations for children. It is recommended that any of the 3 training modalities can be implemented under professional supervision with proper training progressions to enhance training adaptations in children.

  4. Duration Dependent Effect of Static Stretching on Quadriceps and Hamstring Muscle Force

    Directory of Open Access Journals (Sweden)

    Leyla Alizadeh Ebadi

    2018-03-01

    Full Text Available The aim of this study was to determine the acute effect of static stretching on hamstring and quadriceps muscles’ isokinetic strength when applied for various durations to elite athletes, to investigate the effect of different static stretching durations on isokinetic strength, and finally to determine the optimal stretching duration. Fifteen elite male athletes from two different sport branches (10 football and five basketball participated in this study. Experimental protocol was designed as 17 repetitive static stretching exercises for hamstring and quadriceps muscle groups according to the indicated experimental protocols; ((A 5 min jogging; (B 5 min jogging followed by 15 s static stretching; (C 5 min jogging followed by 30 s static stretching; (D 5 min jogging, followed by static stretching for 45 s. Immediately after each protocol, an isokinetic strength test consisting of five repetitions at 60°/s speed and 20 repetitions at 180°/s speed was recorded for the right leg by the Isomed 2000 device. Friedman variance analysis test was employed for data analysis. According to the analyzes, it was observed that 5 min jogging and 15 s stretching exercises increased the isokinetic strength, whereas 30 and 45 s stretching exercises caused a decrease.

  5. Injuries and Injury Prevention in the US Army Band

    Science.gov (United States)

    2006-12-30

    given tests which included: 1) horizontal shoulder flexion and extension and vertical shoulder flexion and extension on a Cybex isokinetic device at 60...rehearsal of the herald trumpets (see Appendix E). Measurements were made using a Larson Davis (LD) Type 800B sound level meter and a LD Type 2559...activity of the trunk musculature during a Feldenkrais Awareness Through Movement lesson. Isokinet Exerc Sci 4: 216-221, 1991. 139. Chinn J, Trujillo D

  6. New Advances in Molecular Therapy for Muscle Repair after Diseases and Injuries

    Science.gov (United States)

    2009-04-01

    throughout. Eleven weeks after the injury, an isokinetic test of the hamstrings was performed showing an essentially normal result. In summary...all isokinetic testing parameters were within a normal range compared to the contralateral leg and well below the usual time of typically healing of a...significant increase in the nu mber a nd in the dia meter of regenerating myofibers in the s uramin tr eated gr oup ( 2.5 mg) when co mpared with

  7. Study on Aerosol Penetration Through Clothing and Individual Protective Equipment

    Science.gov (United States)

    2009-05-01

    8.4X10-3 mg.m-3 (2.57X105 particles per cubic meter of air) over a 30 minute period. This scenario represents a very high end threat with a large... Isokinetic air sampling was applied and the effect of aerosol losses in sampling lines and other parts of the test rig were incorporated in analysis...eliminate any “memory” effect. The aerosol sampling (airflow direction control, start of sampling) was operated manually. Isokinetic sampling conditions

  8. Is gender influencing the biomechanical results after autologous chondrocyte implantation?

    Science.gov (United States)

    Kreuz, Peter C; Müller, Sebastian; Erggelet, Christoph; von Keudell, Arvind; Tischer, Thomas; Kaps, Christian; Niemeyer, Philipp; Hirschmüller, Anja

    2014-01-01

    The influence of gender on the biomechanical outcome after autologous chondrocyte implantation (ACI) including isokinetic muscle strength measurements has not been investigated. The present prospective study was performed to evaluate gender-specific differences in the biomechanical function 48 months after ACI. Fifty-two patients (mean age 35.6 ± 8.5 years) that met our inclusion criteria, underwent ACI with Bioseed C(®) and were evaluated with the KOOS score preoperatively, 6, 12 and 48 months after surgery. At final follow-up, 44 out of the 52 patients underwent biomechanical evaluation with isokinetic strength measurements of both knees. All data were evaluated separately for men and women and compared for each time interval using the Mann-Whitney U test. Clinical scores improved significantly over the whole study period (p genders. Isokinetic muscle strength measures are significantly worse in women (p role for the explanation of gender-specific results after ACI.

  9. Renewable Energy Testing Center for US Army Contract W15QKN-05-D-0030 Task 5 RETC, WBS #4.6.0

    Science.gov (United States)

    2010-02-01

    repeatability. · Establish equipment needed to meter inputs and outputs and establish protocols to measure or test other materials. · Establish... meters for the PEAT PTDR-100 · City water for the PEAT PTDR-100 · Chilled water for the PEAT PTDR-100 · Waste water drain lines and collection sump...diameter were used to isokinetically remove stack gas samples. The method of analysis for collected fi lterable particulate and condensable particulate

  10. The Fate of the Iliopsoas Muscle in Long-term Follow-up After Open Reduction With a Medial Approach in Developmental Dysplasia of the Hip. Part 2: Isokinetic Muscle Strength Evaluation.

    Science.gov (United States)

    Yilmaz, Serdar; Aksahin, Ertugrul; Ersoz, Murat; Bicimoglu, Ali

    2017-09-01

    The impact on long-term weakness of hip flexion of complete iliopsoas tenotomy during open reduction of developmental hip dysplasia with a medial approach has not yet been fully clarified. The purpose of this study was to investigate the isokinetic muscle strength (IMS) of hip flexor and extensor muscles in these patients and also to analyze the effect of spontaneous reattachment of the iliopsoas muscle on IMS measurements. The study included 20 patients. Earlier magnetic resonance imaging examination of all the patients revealed spontaneous reattachment of the iliopsoas in 18 (90%) patients. IMS measurements were performed at 60 and 150 degrees/s. The peak torque, total work (TW), average power (AP), work fatigue, and agonist to antagonist muscle ratio of the operated and nonoperated hips were recorded separately for flexors and extensors. The effect of iliopsoas reattachment on IMS was also evaluated. The mean follow-up period was 16.65±2.16 (13 to 20) years. Total work (P=0.013) and average power (P=0.009) of the flexor muscles and work fatigue of the extensor muscles (P=0.030) of the operated hip were significantly decreased when compared with the nonoperated hips at 150 degrees/s. There was no significant difference between the flexor muscles of the operated and nonoperated hips (Phips. Flexor muscle strength was decreased in the operated hip against low resistance in long-term follow-up after iliopsoas tenotomy. This may reflect that hip muscle strength was decreased after prolonged activities such as sports. However, in forceful activities flexor muscle strength was retained due to iliopsoas reattachment. On the basis of this study we thought that spontaneous reattachment of the iliopsoas tendon substantially preserves muscle strength. Nonetheless possible efforts should be made to surgically reattach the psoas tendon to preserve strength of the muscle. Therapeutic level IV.

  11. Exercise and heat stress: cerebral challenges and consequences

    DEFF Research Database (Denmark)

    Nybo, Lars

    2007-01-01

    , the elevated ratings of perceived exertion and increased release of hypothalamic hormones. While the slowing of the electroencephalographic (EEG), the decreased endurance and hampered ability to activate the skeletal muscles maximally during sustained isometric and repeated isokinetic contractions appear...... that the dopaminergic system is important, but several other factors may interact and feedback from the skeletal muscles and internal temperature sensors are probably also involved. The complexity of brain fatigue response is discussed based on our own investigations and in the light of recent literature....

  12. Relationships of Functional Tests Following ACL Reconstruction: Exploratory Factor Analyses of the Lower Extremity Assessment Protocol.

    Science.gov (United States)

    DiFabio, Melissa; Slater, Lindsay V; Norte, Grant; Goetschius, John; Hart, Joseph M; Hertel, Jay

    2018-03-01

    After ACL reconstruction (ACLR), deficits are often assessed using a variety of functional tests, which can be time consuming. It is unknown whether these tests provide redundant or unique information. To explore relationships between components of a battery of functional tests, the Lower Extremity Assessment Protocol (LEAP) was created to aid in developing the most informative, concise battery of tests for evaluating ACLR patients. Descriptive, cross-sectional. Laboratory. 76 ACLR patients (6.86±3.07 months postoperative) and 54 healthy participants. Isokinetic knee flexion and extension at 90 and 180 degrees/second, maximal voluntary isometric contraction for knee extension and flexion, single leg balance, 4 hopping tasks (single, triple, crossover, and 6-meter timed hop), and a bilateral drop vertical jump that was scored with the Landing Error Scoring System (LESS). Peak torque, average torque, average power, total work, fatigue indices, center of pressure area and velocity, hop distance and time, and LESS score. A series of factor analyses were conducted to assess grouping of functional tests on the LEAP for each limb in the ACLR and healthy groups and limb symmetry indices (LSI) for both groups. Correlations were run between measures that loaded on retained factors. Isokinetic and isometric strength tests for knee flexion and extension, hopping, balance, and fatigue index were identified as unique factors for all limbs. The LESS score loaded with various factors across the different limbs. The healthy group LSI analysis produced more factors than the ACLR LSI analysis. Individual measures within each factor had moderate to strong correlations. Isokinetic and isometric strength, hopping, balance, and fatigue index provided unique information. Within each category of measures, not all tests may need to be included for a comprehensive functional assessment of ACLR patients due to the high amount of shared variance between them.

  13. Multilevel Models for the Analysis of Angle-Specific Torque Curves with Application to Master Athletes

    Directory of Open Access Journals (Sweden)

    Carvalho Humberto M.

    2015-12-01

    Full Text Available The aim of this paper was to outline a multilevel modeling approach to fit individual angle-specific torque curves describing concentric knee extension and flexion isokinetic muscular actions in Master athletes. The potential of the analytical approach to examine between individual differences across the angle-specific torque curves was illustrated including between-individuals variation due to gender differences at a higher level. Torques in concentric muscular actions of knee extension and knee extension at 60°·s-1 were considered within a range of motion between 5°and 85° (only torques “truly” isokinetic. Multilevel time series models with autoregressive covariance structures with standard multilevel models were superior fits compared with standard multilevel models for repeated measures to fit anglespecific torque curves. Third and fourth order polynomial models were the best fits to describe angle-specific torque curves of isokinetic knee flexion and extension concentric actions, respectively. The fixed exponents allow interpretations for initial acceleration, the angle at peak torque and the decrement of torque after peak torque. Also, the multilevel models were flexible to illustrate the influence of gender differences on the shape of torque throughout the range of motion and in the shape of the curves. The presented multilevel regression models may afford a general framework to examine angle-specific moment curves by isokinetic dynamometry, and add to the understanding mechanisms of strength development, particularly the force-length relationship, both related to performance and injury prevention.

  14. A randomized, double-blind, placebo-controlled trial of the effect of subcutaneous immunoglobulin on muscular performance in chronic inflammatory demyelinating polyneuropathy

    DEFF Research Database (Denmark)

    Markvardsen, Lars Høj; Harbo, Thomas; Sindrup, Søren Hein

    before (-2, 0, 10,12 weeks), isokinetic strength performance of four predetermined and weakened muscle groups was performed. Also, the Overall Disability Sum Score (ODSS), 40 meter walking test, nine hole peg test, Neurological Impairment Score (NIS), Medical Research Council (MRC) score and grip...... strength test, standardized electrophysiological recordings from three nerves and plasma IgG levels were obtained. SCIG treatment was well tolerated in all 15 patients for 12 weeks. Six patients complained of mild side effects at the injection site. In the SCIG group there was an increase of isokinetic...

  15. A randomised, double-blinded, placebo-controlled trial of the effect of subcuta-neous immunoglobulin on muscular performance in chronic inflammatory de-myelinating polyneuropathy

    DEFF Research Database (Denmark)

    Harbo, Thomas; Markvardsen, Lars Høj; Sindrup, Søren Hein

    . Participants were evaluated at four time intervals: - 2 weeks, 0, 10 and 12 weeks after treatment with subcutaneous infusions. Muscle strength was determined at isokinetic dynamometry at four predetermined and weakened muscle groups. Moreover, an Overall Disability Sum Score (ODSS), a 40 meter walking test...... at isokinetic dynamometry in the two study groups. Secondary end-points were the treatment response of SCIG vs IVIG and the variation of the treatment response during SCIG vs IVIG. Results: The study ran during the period April 2010 - October 2011. Results will be presented....

  16. MIT extraction method for measuring average subchannel axial velocities in reactor assemblies

    International Nuclear Information System (INIS)

    Hawley, J.T.; Chiu, C.; Todreas, N.E.

    1980-08-01

    The MIT extraction method for obtaining flow split data for individual subchannels is described in detail. An analysis of the method is presented which shows that isokinetic values of the subchannel flow rates are obtained directly even though the method is non-isokinetic. Time saving methods are discussed for obtaining the average value of the interior region flow split parameter. An analysis of the method at low bundle flow rates indicates that there is no inherent low flow rate limitation on the method and suggests a way to obtain laminar flow split data

  17. Concentric resistance training increases muscle strength without affecting microcirculation

    International Nuclear Information System (INIS)

    Weber, Marc-Andre; Hildebrandt, Wulf; Schroeder, Leif; Kinscherf, Ralf; Krix, Martin; Bachert, Peter; Delorme, Stefan; Essig, Marco; Kauczor, Hans-Ulrich; Krakowski-Roosen, Holger

    2010-01-01

    Purpose: While the evidence is conclusive regarding the positive effects of endurance training, there is still some controversy regarding the effects of resistance training on muscular capillarity. Thus, the purpose was to assess whether resistance strength training influences resting skeletal muscle microcirculation in vivo. Materials and methods: Thirty-nine middle-aged subjects (15 female, 24 male; mean age, 54 ± 9 years) were trained twice a week on an isokinetic system (altogether 16 sessions lasting 50 min, intensity 75% of maximum isokinetic and isometric force of knee flexors and extensors). To evaluate success of training, cross-sectional area (CSA) of the quadriceps femoris muscle and its isokinetic and isometric force were quantified. Muscular capillarization was measured in biopsies of the vastus lateralis muscle. In vivo, muscular energy and lipid metabolites were quantified by magnetic resonance spectroscopy and parameters of muscular microcirculation, such as local blood volume, blood flow and velocity, by contrast-enhanced ultrasound analyzing replenishment kinetics. Results: The significant (P 2 after training) and in absolute muscle strength (isometric, 146 ± 44 vs. 174 ± 50 Nm; isokinetic, 151 ± 53 vs. 174 ± 62 Nm) demonstrated successful training. Neither capillary density ex vivo (351 ± 75 vs. 326 ± 62) nor ultrasonographic parameters of resting muscle perfusion were significantly different (blood flow, 1.2 ± 1.2 vs. 1.1 ± 1.1 ml/min/100 g; blood flow velocity, 0.49 ± 0.44 vs. 0.52 ± 0.74 mm s -1 ). Also, the intensities of high-energy phosphates phosphocreatine and β-adenosintriphosphate were not different after training within the skeletal muscle at rest (β-ATP/phosphocreatine, 0.29 ± 0.06 vs. 0.28 ± 0.04). Conclusion: The significant increase in muscle size and strength in response to concentric isokinetic and isometric resistance training occurs without an increase in the in vivo microcirculation of the skeletal muscles at

  18. Concentric resistance training increases muscle strength without affecting microcirculation

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Marc-Andre [Department of Diagnostic and Interventional Radiology, University of Heidelberg, Heidelberg (Germany)], E-mail: MarcAndre.Weber@med.uni-heidelberg.de; Hildebrandt, Wulf [Immunochemistry, German Cancer Research Center (dkfz), Heidelberg (Germany); Schroeder, Leif [Medical Physics in Radiology, German Cancer Research Center (dkfz), Heidelberg (Germany); Kinscherf, Ralf [Department of Anatomy and Developmental Biology, University of Heidelberg, Heidelberg (Germany); Krix, Martin [Radiology, German Cancer Research Center (dkfz), Heidelberg (Germany); Bachert, Peter [Medical Physics in Radiology, German Cancer Research Center (dkfz), Heidelberg (Germany); Delorme, Stefan; Essig, Marco [Radiology, German Cancer Research Center (dkfz), Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University of Heidelberg, Heidelberg (Germany); Krakowski-Roosen, Holger [National Center for Tumor Diseases (NCT), Heidelberg (Germany)

    2010-03-15

    Purpose: While the evidence is conclusive regarding the positive effects of endurance training, there is still some controversy regarding the effects of resistance training on muscular capillarity. Thus, the purpose was to assess whether resistance strength training influences resting skeletal muscle microcirculation in vivo. Materials and methods: Thirty-nine middle-aged subjects (15 female, 24 male; mean age, 54 {+-} 9 years) were trained twice a week on an isokinetic system (altogether 16 sessions lasting 50 min, intensity 75% of maximum isokinetic and isometric force of knee flexors and extensors). To evaluate success of training, cross-sectional area (CSA) of the quadriceps femoris muscle and its isokinetic and isometric force were quantified. Muscular capillarization was measured in biopsies of the vastus lateralis muscle. In vivo, muscular energy and lipid metabolites were quantified by magnetic resonance spectroscopy and parameters of muscular microcirculation, such as local blood volume, blood flow and velocity, by contrast-enhanced ultrasound analyzing replenishment kinetics. Results: The significant (P < 0.001) increase in CSA (60 {+-} 16 before vs. 64 {+-} 15 cm{sup 2} after training) and in absolute muscle strength (isometric, 146 {+-} 44 vs. 174 {+-} 50 Nm; isokinetic, 151 {+-} 53 vs. 174 {+-} 62 Nm) demonstrated successful training. Neither capillary density ex vivo (351 {+-} 75 vs. 326 {+-} 62) nor ultrasonographic parameters of resting muscle perfusion were significantly different (blood flow, 1.2 {+-} 1.2 vs. 1.1 {+-} 1.1 ml/min/100 g; blood flow velocity, 0.49 {+-} 0.44 vs. 0.52 {+-} 0.74 mm s{sup -1}). Also, the intensities of high-energy phosphates phosphocreatine and {beta}-adenosintriphosphate were not different after training within the skeletal muscle at rest ({beta}-ATP/phosphocreatine, 0.29 {+-} 0.06 vs. 0.28 {+-} 0.04). Conclusion: The significant increase in muscle size and strength in response to concentric isokinetic and isometric

  19. Influência do volume de alongamento estático dos músculos isquiotibiais nas variavéis isocinéticas Influence of static stretching volume in isokinetic variables of harmstrings

    Directory of Open Access Journals (Sweden)

    Anselmo Grego Neto

    2009-04-01

    trabalho ao longo de algumas repetições não é.Stretching exercises are commonly prescribed before training sessions and competitions aiming at performance improvement and reduction of injury risk. However, many studies have shown that muscular torque production capacity may be reduced just after stretching. Therefore, the stretching duration necessary to produce these acute force deficits, as well as the physiological mechanisms responsible for them are relevant issues. The aim of this work was to investigate the acute effects of static stretching protocols with different durations on the isokinetic hamstrings performance. Thirty-six young male volunteers took part in this study and were evenly distributed in three groups: E1, E2 and C. All of them performed a systemic warm-up for five minutes and went through active range of motion (AROM of hip flexion and isokinetic assessment. The participants of groups E1 and E2 performed static stretching protocols of 180s (4 x 45s and 360s (8 x 45s respectively, and were evaluated again. The participants of group C (control remained at rest for a period of 270s and were evaluated again. The variables considered were AROM, peak torque, maximum work and total work. Both stretching protocols were able to produce increase in AROM; however, only the longest protocol produced deficits on peak torque and maximum work. Total work was not affected by any of the stretching protocols, though. Therefore, these results suggest that changes in muscular stiffness, that caused AROM gain, would not be responsible alone for the force deficits. Moreover, one can conclude that the maximum muscular strength depends on the stretching duration, but the muscular work along some repetitions of an exercise does not.

  20. Reliability and relationships among handgrip strength, leg extensor strength and power, and balance in older men.

    Science.gov (United States)

    Jenkins, Nathaniel D M; Buckner, Samuel L; Bergstrom, Haley C; Cochrane, Kristen C; Goldsmith, Jacob A; Housh, Terry J; Johnson, Glen O; Schmidt, Richard J; Cramer, Joel T

    2014-10-01

    To quantify the reliability of isometric leg extension torque (LEMVC), rate of torque development (LERTD), isometric handgrip force (HGMVC) and RFD (HGRFD), isokinetic leg extension torque and power at 1.05rad·s(-1) and 3.14rad·s(-1); and explore relationships among strength, power, and balance in older men. Sixteen older men completed 3 isometric handgrips, 3 isometric leg extensions, and 3 isokinetic leg extensions at 1.05rad·s(-1) and 3.14rad·s(-1) during two visits. Intraclass correlation coefficients (ICCs), ICC confidence intervals (95% CI), coefficients of variation (CVs), and Pearson correlation coefficients were calculated. LERTD demonstrated no reliability. The CVs for LERTD and HGRFD were ≤23.26%. HGMVC wasn't related to leg extension torque or power, or balance (r=0.14-0.47; p>0.05). However, moderate to strong relationships were found among isokinetic leg extension torque at 1.05rad·s(-1) and 3.14rad·s(-1), leg extension mean power at 1.05rad·s(-1), and functional reach (r=0.51-0.95; p≤0.05). LERTD and HGRFD weren't reliable and shouldn't be used as outcome variables in older men. Handgrip strength may not be an appropriate surrogate for lower body strength, power, or balance. Instead, perhaps handgrip strength should only be used to describe upper body strength or functionality, which may compliment isokinetic assessments of lower body strength, which were reliable and related to balance. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. A randomised, double-blinded, placebo controlled trial of the effect of subcutaneous immunoglobulin on muscular performance in chronic inflammatory demyelinating polyneuropathy

    DEFF Research Database (Denmark)

    Jakobsen, Johannes Klitgaard; Markvardsen, Lars Høj; Harbo, Thomas

    . Participants were evaluated at four time intervals: - 2 wks, 0, 10 wks, 12 wks. Strength was determined at isokinetic dynamometry from four predetermined and weakened muscle groups. Also, an Overall Disability Sum Score (ODSS), a 40 meter walking test, a nine hole peg test, a Neurological Impairment Score (NIS......), a Medical Research Council (MRC) score and a grip strength test were included. The primary end-point is the change of strength at isokinetic dynamometry in the two study groups. Secondary end-points are the treatment response of SCIG vs IVIG and the variation of the treatment response during SCIG vs IVIG...

  2. Discussion about different cut-off values of conventional hamstring-to-quadriceps ratio used in hamstring injury prediction among professional male football players.

    Science.gov (United States)

    Grygorowicz, Monika; Michałowska, Martyna; Walczak, Tomasz; Owen, Adam; Grabski, Jakub Krzysztof; Pyda, Andrzej; Piontek, Tomasz; Kotwicki, Tomasz

    2017-01-01

    To measure the sensitivity and specificity of differences cut-off values for isokinetic Hcon/Qcon ratio in order to improve the capacity to evaluate (retrospectively) the injury of hamstring muscles in professional soccer screened with knee isokinetic tests. Retrospective study. Medical and biomechanical data of professional football players playing for the same team for at least one season between 2010 and 2016 were analysed. Hamstring strain injury cases and the reports generated via isokinetic testing were investigated. Isokinetic concentric(con) hamstring(H) and quadriceps(Q) absolute strength in addition with Hcon/Qcon ratio were examined for the injured versus uninjured limbs among injured players, and for the injured and non-injured players. 2 x 2 contingency table was used for comparing variables: predicted injured or predicted uninjured with actual injured or actual uninjured. Sensitivity, specificity, accuracy, positive and negative predictive values, and positive and negative likelihood ratio were calculated for three different cut-off values (0.47 vs. 0.6 vs. 0.658) to compare the discriminative power of an isokinetic test, whilst examining the key value of Hcon/Qcon ratio which may indicate the highest level of ability to predispose a player to injury. McNemar's chi2 test with Yates's correction was used to determine agreement between the tests. PQStat software was used for all statistical analysis, and an alpha level of p hamstring injuries during the analysed period. None of these players sustained recurrence of hamstring injury. One player sustained hamstring strain injury on both legs, thus the total number of injuries was 12. Application of different cut-off values for Hcon/Qcon significantly affected the sensitivity and specificity of isokinetic test used as a tool for muscle injury detection. The use of 0.47 of Hcon/Qcon as a discriminate value resulted in significantly lower sensitivity when compared to 0.658 threshold (sensitivity of 16.7% vs

  3. An investigation of leg and trunk strength and reaction times of hard-style martial arts practitioners.

    Science.gov (United States)

    Donovan, Oliver O; Cheung, Jeanette; Catley, Maria; McGregor, Alison H; Strutton, Paul H

    2006-01-01

    The purpose of this study was to investigate trunk and knee strength in practitioners of hard-style martial arts. An additional objective was to examine reaction times in these participants by measuring simple reaction times (SRT), choice reaction times (CRT) and movement times (MT). Thirteen high-level martial artists and twelve sedentary participants were tested under isokinetic and isometric conditions on an isokinetic dynamometer. Response and movement times were also measured in response to simple and choice auditory cues. Results indicated that the martial arts group generated a greater body-weight adjusted peak torque with both legs at all speeds during isokinetic extension and flexion, and in isometric extension but not flexion. In isokinetic and isometric trunk flexion and extension, martial artists tended to have higher peak torques than controls, but they were not significantly different (p > 0.05). During the SRT and CRT tasks the martial artists were no quicker in lifting their hand off a button in response to the stimulus [reaction time (RT)] but were significantly faster in moving to press another button [movement time (MT)]. In conclusion, the results reveal that training in a martial art increases the strength of both the flexors and extensors of the leg. Furthermore, they have faster movement times to auditory stimuli. These results are consistent with the physical aspects of the martial arts. Key PointsMartial artists undertaking hard-style martial arts have greater strength in their knee flexor and extensor muscles as tested under isokinetic testing. Under isometric testing conditions they have stronger knee extensors only.The trunk musculature is generally higher under both conditions of testing in the martial artists, although not significantly.The total reaction times of the martial artists to an auditory stimulus were significantly faster than the control participants. When analysed further it was revealed that the decrease in reaction time

  4. Preseason Strength Assessment of the Rotator Muscles and Shoulder Injury in Handball Players.

    Science.gov (United States)

    Forthomme, Bénédicte; Croisier, Jean-Louis; Delvaux, François; Kaux, Jean-François; Crielaard, Jean-Michel; Gleizes-Cervera, Sophie

    2018-02-01

      Few researchers have identified intrinsic risk factors for shoulder injury in team handball players by analyzing measurements of maximal isokinetic rotator muscle strength.   To identify possible intrinsic risk factors for shoulder injury by analyzing measurements of maximal isokinetic rotator muscle strength.   Cross-sectional study.   Male team handball senior divisions (the highest level) in France and Belgium.   A total of 108 male high-level handball players (age = 24 ± 4 years, height = 189 ± 6 cm, mass = 87 ± 11 kg) were enrolled.   All players completed a preseason questionnaire and performed a bilateral isokinetic assessment of the shoulder rotator muscles. On a monthly questionnaire, players reported any shoulder injury that they sustained during the season.   On the preseason questionnaire, 51 of 108 (47%) participants reported a history of dominant-shoulder injury. A total of 106 participants completed the in-season questionnaire, with 22% (n = 23) reporting a shoulder injury on their dominant side during the subsequent season. Fourteen percent (n = 15) sustained microtraumatic injuries, and 8% (n = 8) described a traumatic injury. Backcourt players had a 3.5-times increased risk of injury during the new season compared with players in other positions. Among the isokinetic results, no risk factor for further injury was identified in handball players with microtraumatic injuries. For traumatic injuries, the concentric maximal strength developed by the internal rotators at high speed (240°/s) in the dominant shoulder was a protective factor against the risk of further injury.   These results can potentially identify intrinsic risk factors for shoulder injury and may be used to determine potential interventions for reducing this risk in handball players.

  5. Instantaneous quantification of skeletal muscle activation, power production, and fatigue during cycle ergometry.

    Science.gov (United States)

    Coelho, A C; Cannon, D T; Cao, R; Porszasz, J; Casaburi, R; Knorst, M M; Rossiter, H B

    2015-03-01

    A rapid switch from hyperbolic to isokinetic cycling allows the velocity-specific decline in maximal power to be measured, i.e., fatigue. We reasoned that, should the baseline relationship between isokinetic power (Piso) and electromyography (EMG) be reproducible, then contributions to fatigue may be isolated from 1) the decline in muscle activation (muscle activation fatigue); and 2) the decline in Piso at a given activation (muscle fatigue). We hypothesized that the EMG-Piso relationship is linear, velocity dependent, and reliable for instantaneous fatigue assessment at intolerance during and following whole body exercise. Healthy participants (n = 13) completed short (5 s) variable-effort isokinetic bouts at 50, 70, and 100 rpm to characterize baseline EMG-Piso. Repeated ramp incremental exercise tests were terminated with maximal isokinetic cycling (5 s) at 70 rpm. Individual baseline EMG-Piso relationships were linear (r(2) = 0.95 ± 0.04) and velocity dependent (analysis of covariance). Piso at intolerance (two legs, 335 ± 88 W) was ∼45% less than baseline [630 ± 156 W, confidence interval of the difference (CIDifference) 211, 380 W, P fatigue and muscle fatigue (one leg) were 97 ± 55 and 60 ± 50 W, respectively. Mean bias ± limits of agreement for reproducibility were as follows: baseline Piso 1 ± 30 W; Piso at 0-min recovery 3 ± 35 W; and EMG at Piso 3 ± 14%. EMG power is linear, velocity dependent, and reproducible. Deviation from this relationship at the limit of tolerance can quantify the "activation" and "muscle" related components of fatigue during cycling. Copyright © 2015 the American Physiological Society.

  6. Carbohydrate vs protein supplementation for recovery of neuromuscular function following prolonged load carriage

    Directory of Open Access Journals (Sweden)

    Fallowfield Joanne L

    2010-01-01

    Full Text Available Abstract Background This study examined the effect of carbohydrate and whey protein supplements on recovery of neuromuscular function after prolonged load carriage. Methods Ten male participants (body mass: 81.5 ± 10.5 kg, age: 28 ± 9 years, O2max: 55.0 ± 5.5 ml·kg-1·min-1 completed three treadmill walking tests (2 hr, 6.5 km·h-1, carrying a 25 kg backpack consuming 500 ml of either: (1 Placebo (flavoured water [PLA], (2 6.4% Carbohydrate Solution [CHO] or (3 7.0% Whey Protein Solution [PRO]. For three days after load carriage, participants consumed two 500 ml supplement boluses. Muscle performance was measured before and at 0, 24, 48 and 72 h after load carriage, during voluntary and electrically stimulated contractions. Results Isometric knee extension force decreased immediately after load carriage with no difference between conditions. During recovery, isometric force returned to pre-exercise values at 48 h for CHO and PRO but at 72 h for PLA. Voluntary activation decreased immediately after load carriage and returned to pre-exercise values at 24 h in all conditions (P = 0.086. During recovery, there were no differences between conditions for the change in isokinetic peak torque. Following reductions immediately after load carriage, knee extensor and flexor peak torque (60°·s-1 recovered to pre-exercise values at 72 h. Trunk extensor and flexor peak torque (15°·s-1 recovered to pre-exercise values at 24 h (P = 0.091 and 48 h (P = 0.177, respectively. Conclusion Recovery of neuromuscular function after prolonged load carriage is improved with either carbohydrate or whey protein supplementation for isometric contractions but not for isokinetic contractions.

  7. Hip abduction-adduction strength and one-leg hop tests: test-retest reliability and relationship to function in elite ice hockey players.

    Science.gov (United States)

    Kea, J; Kramer, J; Forwell, L; Birmingham, T

    2001-08-01

    Single group, test-retest. To determine: (1) hip abduction and adduction torques during concentric and eccentric muscle actions, (2) medial and lateral one-leg hop distances, (3) the test-retest reliability of these measurements, and (4) the relationship between isokinetic measures of hip muscle strength and hop distances in elite ice hockey players. The skating motion used in ice hockey requires strong contractions of the hip and knee musculature. However, baseline scores for hip strength and hop distances, their test-retest reliability, and measures of the extent to which these tests are related for this population are not available. The dominant leg of 27 men (mean age 20 +/- 3 yrs) was tested on 2 occasions. Hip abduction and adduction movements were completed at 60 degrees.s(-1) angular velocity, with the subject lying on the non-test side and the test leg moving vertically in the subject's coronal plane. One-leg hops requiring jumping from and landing on the same leg without losing balance were completed in the medial and lateral directions. Hip adduction torques were significantly greater than abduction torques during both concentric and eccentric muscle actions, while no significant difference was observed between medial and lateral hop distances. Although hop test scores produced excellent ICCs (> 0.75) when determined using scores on 1 occasion, torques needed to be averaged over 2 test occasions to reach this level. Correlations between the strength and hop tests ranged from slight to low (r = -0.26 to 0.27) and were characterized by wide 95% confidence intervals (-0.54 to 0.61). Isokinetic tests of hip abduction and adduction did not provide a strong indication of performance during sideways hop tests. Although isokinetic tests can provide a measure of muscular strength under specific test conditions, they should not be relied upon as a primary indicator of functional abilities or readiness to return to activity.

  8. Competitive swimmers with hypermobility have strength and fatigue deficits in shoulder medial rotation

    DEFF Research Database (Denmark)

    Liaghat, Behnam; Juul-Kristensen, Birgit; Frydendal, Thomas

    2018-01-01

    rotation (60°/s). Swimmers with GJHS showed significantly larger isokinetic fatigue at 180°/s (0.321 J/repetition; p = .010), and tendencies to lower levels of muscle activity in infraspinatus (20%, p = .066) and pectoralis major (34%, p = .092) at 60°/s during medial rotation. Young competitive swimmers...... rotations. Totally, 38 competitive swimmers (aged 13-17 years) participated, 19 were competitive swimmers with GJHS and 19 were age, sex and club matched swimmers without GJHS. Concentric isokinetic force in medial and lateral rotations were measured at 60°/s (5 repetitions) and 180°/s (10 repetitions...

  9. Multiple time step molecular dynamics in the optimized isokinetic ensemble steered with the molecular theory of solvation: Accelerating with advanced extrapolation of effective solvation forces

    International Nuclear Information System (INIS)

    Omelyan, Igor; Kovalenko, Andriy

    2013-01-01

    We develop efficient handling of solvation forces in the multiscale method of multiple time step molecular dynamics (MTS-MD) of a biomolecule steered by the solvation free energy (effective solvation forces) obtained from the 3D-RISM-KH molecular theory of solvation (three-dimensional reference interaction site model complemented with the Kovalenko-Hirata closure approximation). To reduce the computational expenses, we calculate the effective solvation forces acting on the biomolecule by using advanced solvation force extrapolation (ASFE) at inner time steps while converging the 3D-RISM-KH integral equations only at large outer time steps. The idea of ASFE consists in developing a discrete non-Eckart rotational transformation of atomic coordinates that minimizes the distances between the atomic positions of the biomolecule at different time moments. The effective solvation forces for the biomolecule in a current conformation at an inner time step are then extrapolated in the transformed subspace of those at outer time steps by using a modified least square fit approach applied to a relatively small number of the best force-coordinate pairs. The latter are selected from an extended set collecting the effective solvation forces obtained from 3D-RISM-KH at outer time steps over a broad time interval. The MTS-MD integration with effective solvation forces obtained by converging 3D-RISM-KH at outer time steps and applying ASFE at inner time steps is stabilized by employing the optimized isokinetic Nosé-Hoover chain (OIN) ensemble. Compared to the previous extrapolation schemes used in combination with the Langevin thermostat, the ASFE approach substantially improves the accuracy of evaluation of effective solvation forces and in combination with the OIN thermostat enables a dramatic increase of outer time steps. We demonstrate on a fully flexible model of alanine dipeptide in aqueous solution that the MTS-MD/OIN/ASFE/3D-RISM-KH multiscale method of molecular dynamics

  10. A New Training for Older Adults Using Combined Neuromuscular Electrical Stimulation and Volitional Contraction: A Pilot Study.

    Science.gov (United States)

    Takano, Yoshio; Matsuse, Hiroo; Tsukada, Yuuya; Omoto, Masayuki; Hashida, Ryuki; Shiba, Naoto

    2016-01-01

    The hybrid training system (HTS) resists the motion of a volitionally contracting agonist muscle using force generated by its electrically stimulated antagonist. We have developed a new training method using the principle of HTS. This study was designed to evaluate the effect of HTS with electrical stimulation on muscle strength and physical function by comparing it against training without electrical stimulation in older adults. 16 subjects were randomly divided into two groups: the squat and single leg lift training (control, CTR) group, and the CTR with HTS training group. Some electrical stimulation was applied to the quadriceps and hamstring muscles in the HTS group. The subjects performed training for 25 min per session 3 times a week for 12 weeks. At points before and after the research maximal isokinetic torque, knee-flexors (KFT) and knee-extensors (KET), a one-leg standing test (OLT), a functional reach test (FRT), a 10-meter maximal gait time (10MGT) and Timed up & go test (TUG) were conducted. None of the subjects had any injuries during the study period. TUG significantly improved after the training period in both the HTS group (7.15 sec to 6.01 sec P = 0.01) and in the CTR.

  11. Isokinetic strength of knee flexors and extensors of adolescent soccer players and its changes based on movement speed and age [Izokinetická síla flexorů a extenzorů kolena u adolescentních fotbalistů a její změny s rychlostí pohybu a s věkem

    Directory of Open Access Journals (Sweden)

    Rudolf Psotta

    2011-06-01

    Full Text Available BACKGROUND: During childhood and adolescence there is growth in muscle strength. The dynamics of change in muscle strength and its causes have not yet been fully clarified and may differ within individuals and specific groups. The knowledge of current isokinetic strength levels among athletes of varying ages and disciplines represents important information from the point of view of sport performance, as well as health prevention. OBJECTIVE: The aim of this study is to determine within a group of highly trained adolescent soccer players (n = 45; age = 17 ± 1.2 years; body height 178.4 ± 5.3 cm, body weight 68.5 ± 7.6 kg the isokinetic strength of knee flexors and extensors and to judge whether it is significantly influenced by age and movement speed. METHODS: A group of players was further divided according to age into 3 subgroups – U16 (n = 16; U17 (n = 14; U18 (n = 15. Unilateral strength was measured by the isokinetic dynamometer ISOMED 2000 (D. & R. Ferstl GmbH, Hemau, Germany at angular speeds of 60° • s-1, 180° • s-1 and 360° • s-1. The parameter evaluated was the isokinetic peak torque (PT; Nm. RESULTS: The ANOVA results demonstrate that there was a significant decrease in the PT within the entire group of players with an increase in speed during both flexion and extension (dominant extremity: p < 0.001 resp. p < 0.019; non-dominant extremity: p < 0.001; resp. p < 0.001. The difference in PT among the age categories was not significant for both flexors and extensors at the speed of 60° ∙ s-1 (p = 0.005; resp. p = 0.036 and the speed of 180° ∙ s-1 (p = 0.036; resp. p = 0.033. However, significant differences in PT among individual categories were confirmed only in some cases and, by contrast, an insignificant decrease was marked with nondominant leg extensors. CONCLUSIONS: The results of this study indicated the state of the strength readiness of the highly trained soccer players in the junior category and the potential

  12. Electromyographic analysis of exercise resulting in symptoms of muscle damage.

    Science.gov (United States)

    McHugh, M P; Connolly, D A; Eston, R G; Gleim, G W

    2000-03-01

    Surface electromyographic (EMG) signals were recorded from the hamstring muscles during six sets of submaximal isokinetic (2.6 rad x s(-1)) eccentric (11 men, 9 women) or concentric (6 men, 4 women) contractions. The EMG per unit torque increased during eccentric (P exercise. Similarly, the median frequency increased during eccentric (P exercise. The EMG per unit torque was lower for submaximal eccentric than maximum isometric contractions (P unit torque was lower for eccentric than concentric contractions (P exercise resulted in significant isometric strength loss (P exercise, while the most severe pain and muscle tenderness occurred 2 days after eccentric exercise. A lower EMG per unit torque is consistent with the selective recruitment of a small number of motor units during eccentric exercise. A higher median frequency during eccentric contractions may be explained by selective recruitment of fast-twitch motor units. The present results are consistent with the theory that muscle damage results from excessive stress on a small number of active fibres during eccentric contractions.

  13. H:q ratios and bilateral leg strength in college field and court sports players.

    Science.gov (United States)

    Cheung, Roy T H; Smith, Andrew W; Wong, Del P

    2012-06-01

    One of the key components in sports injury prevention is the identification of imbalances in leg muscle strength. However, different leg muscle characteristics may occur in large playing area (field) sports and small playing area (court) sports, which should be considered in regular injury prevention assessment. This study examined the isokinetic hamstrings-to-quadriceps (H:Q) ratio and bilateral leg strength balance in 40 male college (age: 23.4 ± 2.5 yrs) team sport players (field sport = 23, soccer players; court sport = 17, volleyball and basketball players). Five repetitions of maximal knee concentric flexion and concentric extension were performed on an isokinetic dynamometer at two speeds (slow: 60°·s(-1) and fast: 300°·s(-1)) with 3 minutes rest between tests. Both legs were measured in counterbalanced order with the dominant leg being determined as the leg used to kick a ball. The highest concentric peak torque values (Nm) of the hamstrings and quadriceps of each leg were analyzed after body mass normalization (Nm·kg(-1)). Court sport players showed significantly weaker dominant leg hamstrings muscles at both contraction speeds (P Sport-specific leg muscle strength was evident in college players from field and court sports. These results suggest the need for different muscle strength training and rehabilitation protocols for college players according to the musculature requirements in their respective sports.

  14. Effects of squat lift training and free weight muscle training on maximum lifting load and isolinetic peak torque of young adults without impairments.

    Science.gov (United States)

    Yeung, S S; Ng, G Y

    2000-06-01

    Manual lifting is a frequent cause of back injury, and there is no evidence as to which training mode can provide the best training effect for lifting performance and muscle force. The purpose of this study was to examine the effects of a squat lift training and a free weight muscle training program on the maximum lifting load and isokinetic peak torque in subjects without known neuromuscular or musculoskeletal impairments. Thirty-six adults (20 male, 16 female) without known neuromuscular or musculoskeletal impairments participated. The subjects' mean age was 21.25 years (SD=1.16, range=20-24). Subjects were divided into 3 groups. Subjects in group 1 (n=12) performed squat lift training. Subjects in group 2 (n=12) participated in free weight resistance training of their shoulder abductors, elbow flexors, knee extensors and trunk extensors. Subjects in group 3 (n=12) served as controls. The maximum lifting load and isokinetic peak torques of the trunk extensors, knee extensors, elbow flexors, and shoulder abductors of each subject were measured before and after the study. Training was conducted on alternate days for 4 weeks, with an initial load of 80% of each subject's maximum capacity and with the load increased by 5% weekly. All groups were comparable for all measured variables before the study. After 4 weeks, subjects in groups 1 and 2 demonstrated more improvement in maximum lifting load and isokinetic peak torque of the back extensors compared with the subjects in group 3, but the 2 training groups were not different. The findings demonstrate that both squat lift and free weight resistance training are equally effective in improving the lifting load and isokinetic back extension performance of individuals without impairments.

  15. Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station.

    Science.gov (United States)

    Shiba, Naoto; Matsuse, Hiroo; Takano, Yoshio; Yoshimitsu, Kazuhiro; Omoto, Masayuki; Hashida, Ryuki; Tagawa, Yoshihiko; Inada, Tomohisa; Yamada, Shin; Ohshima, Hiroshi

    2015-01-01

    Musculoskeletal atrophy is one of the major problems of extended periods of exposure to weightlessness such as on the International Space Station (ISS). We developed the Hybrid Training System (HTS) to maintain an astronaut's musculoskeletal system using an electrically stimulated antagonist to resist the volitional contraction of the agonist instead of gravity. The present study assessed the system's orbital operation capability and utility, as well as its preventative effect on an astronaut's musculoskeletal atrophy. HTS was attached to the non-dominant arm of an astronaut staying on the ISS, and his dominant arm without HTS was established as the control (CTR). 10 sets of 10 reciprocal elbow curls were one training session, and 12 total sessions of training (3 times per week for 4 weeks) were performed. Pre and post flight ground based evaluations were performed by Biodex (muscle performance), MRI (muscle volume), and DXA (BMD, lean [muscle] mass, fat mass). Pre and post training inflight evaluations were performed by a hand held dynamometer (muscle force) and a measuring tape (upper arm circumference). The experiment was completed on schedule, and HTS functioned well without problems. Isokinetic elbow extension torque (Nm) changed -19.4% in HTS, and -21.7% in CTR. Isokinetic elbow flexion torque changed -23.7% in HTS, and there was no change in CTR. Total Work (Joule) of elbow extension changed -8.3% in HTS, and +0.3% in CTR. For elbow flexion it changed -23.3% in HTS and -32.6% in CTR. Average Power (Watts) of elbow extension changed +22.1% in HTS and -8.0% in CTR. For elbow flexion it changed -6.5% in HTS and -4.8% in CTR. Triceps muscle volume according to MRI changed +11.7% and that of biceps was +2.1% using HTS, however -0.1% and -0.4% respectively for CTR. BMD changed +4.6% in the HTS arm and -1.2% for CTR. Lean (muscle) mass of the arm changed only +10.6% in HTS. Fat mass changed -12.6% in HTS and -6.4% in CTR. These results showed the orbital operation

  16. Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station.

    Directory of Open Access Journals (Sweden)

    Naoto Shiba

    Full Text Available Musculoskeletal atrophy is one of the major problems of extended periods of exposure to weightlessness such as on the International Space Station (ISS. We developed the Hybrid Training System (HTS to maintain an astronaut's musculoskeletal system using an electrically stimulated antagonist to resist the volitional contraction of the agonist instead of gravity. The present study assessed the system's orbital operation capability and utility, as well as its preventative effect on an astronaut's musculoskeletal atrophy.HTS was attached to the non-dominant arm of an astronaut staying on the ISS, and his dominant arm without HTS was established as the control (CTR. 10 sets of 10 reciprocal elbow curls were one training session, and 12 total sessions of training (3 times per week for 4 weeks were performed. Pre and post flight ground based evaluations were performed by Biodex (muscle performance, MRI (muscle volume, and DXA (BMD, lean [muscle] mass, fat mass. Pre and post training inflight evaluations were performed by a hand held dynamometer (muscle force and a measuring tape (upper arm circumference.The experiment was completed on schedule, and HTS functioned well without problems. Isokinetic elbow extension torque (Nm changed -19.4% in HTS, and -21.7% in CTR. Isokinetic elbow flexion torque changed -23.7% in HTS, and there was no change in CTR. Total Work (Joule of elbow extension changed -8.3% in HTS, and +0.3% in CTR. For elbow flexion it changed -23.3% in HTS and -32.6% in CTR. Average Power (Watts of elbow extension changed +22.1% in HTS and -8.0% in CTR. For elbow flexion it changed -6.5% in HTS and -4.8% in CTR. Triceps muscle volume according to MRI changed +11.7% and that of biceps was +2.1% using HTS, however -0.1% and -0.4% respectively for CTR. BMD changed +4.6% in the HTS arm and -1.2% for CTR. Lean (muscle mass of the arm changed only +10.6% in HTS. Fat mass changed -12.6% in HTS and -6.4% in CTR.These results showed the orbital

  17. A Comparison of Exercise-Induced Muscle Damage Following Maximal Eccentric Contractions in Men and Boys.

    Science.gov (United States)

    Deli, Chariklia K; Fatouros, Ioannis G; Paschalis, Vassilis; Georgakouli, Kalliopi; Zalavras, Athanasios; Avloniti, Alexandra; Koutedakis, Yiannis; Jamurtas, Athanasios Z

    2017-08-01

    Research regarding exercise-induced muscle-damage mainly focuses on adults. The present study examined exercise-induced muscle-damage responses in adults compared with children. Eleven healthy boys (10-12 y) and 15 healthy men (18-45 y) performed 5 sets of 15 maximal eccentric contractions of the knee extensors. Range of motion (ROM), delayed onset muscle soreness (DOMS) during squat and walking, and peak isometric, concentric and eccentric torque were assessed before, post, 24, 48, 72, and 96 hr postexercise. Creatine kinase (CK) activity was assessed before and 72 hr postexercise. Eccentric exercise resulted in DOMS during squat that persisted for up to 96h in men, and 48 hr in boys (p < .05), and DOMS during walking that persisted for up to 72 hr in men, and 48 hr in boys (p < .01). The ROM was lower in both age groups 48 hr postexercise (p < .001). Isometric (p < .001), concentric (p < .01) and eccentric (p < .01) force decreased post, and up to 48 hr postexercise in men. Except for a reduction in isometric force immediately after exercise, no other changes occurred in boys' isokinetic force. CK activity increased in men at 72 hr postexercise compared with pre exercise levels (p = .05). Our data provide further confirmation that children are less susceptible to exercise-induced muscle damage compared with adults.

  18. Relationships between the mechanomyographic amplitude patterns of response and concentric isokinetic fatiguing tasks of the leg extensors

    International Nuclear Information System (INIS)

    Cooper, Michael A; Herda, Trent J; Fry, Andrew C; Vardiman, John P; Gallagher, Phillip M

    2013-01-01

    The purpose of the present study was to examine possible correlations between the b terms (slopes) form the log-transformed mechanomyographic amplitude (MMG RMS )–force relationships and the fatigue index calculated from 50 maximal concentric contractions. Forty healthy subjects (age = 21 ± 2 yr) performed isometric ramp contractions from 5% to 85% of their maximal voluntary contraction followed by a 50-repetition concentric fatigue protocol of the leg extensors, fatigue index (%) was calculated from the 50-repetitions. MMG was recorded during the ramp contractions from the vastus lateralis (VL) and rectus femoris (RF). The b terms (slopes) were calculated from the log-transformed MMG RMS –force relationships. Correlations were performed comparing the b terms from the MMG RMS –force relationships for the VL and RF with the fatigue index. Significant positive correlations were found among the b terms from the MMG RMS –force relationships for the VL (p = 0.007, r = 0.417) and RF (p = 0.014, r = 0.386) with the fatigue index. The b terms from the log-transformed MMG RMS –force relationships for the VL and RF may have reflected muscle fiber type composition and, thus, correlated with the fatigue index. This adds further support that the MMG RMS –force relationships may reflect muscle fiber type composition. (paper)

  19. Reliability, Validity, and Sensitivity of a Novel Smartphone-Based Eccentric Hamstring Strength Test in Professional Football Players.

    Science.gov (United States)

    Lee, Justin W Y; Cai, Ming-Jing; Yung, Patrick S H; Chan, Kai-Ming

    2018-05-01

    To evaluate the test-retest reliability, sensitivity, and concurrent validity of a smartphone-based method for assessing eccentric hamstring strength among male professional football players. A total of 25 healthy male professional football players performed the Chinese University of Hong Kong (CUHK) Nordic break-point test, hamstring fatigue protocol, and isokinetic hamstring strength test. The CUHK Nordic break-point test is based on a Nordic hamstring exercise. The Nordic break-point angle was defined as the maximum point where the participant could no longer support the weight of his body against gravity. The criterion for the sensitivity test was the presprinting and postsprinting difference of the Nordic break-point angle with a hamstring fatigue protocol. The hamstring fatigue protocol consists of 12 repetitions of the 30-m sprint with 30-s recoveries between sprints. Hamstring peak torque of the isokinetic hamstring strength test was used as the criterion for validity. A high test-retest reliability (intraclass correlation coefficient = .94; 95% confidence interval, .82-.98) was found in the Nordic break-point angle measurements. The Nordic break-point angle significantly correlated with isokinetic hamstring peak torques at eccentric action of 30°/s (r = .88, r 2  = .77, P hamstring strength measures among male professional football players.

  20. Do oarsmen have asymmetries in the strength of their back and leg muscles?

    Science.gov (United States)

    Parkin, S; Nowicky, A V; Rutherford, O M; McGregor, A H

    2001-07-01

    The aim of this study was to establish whether asymmetry of the strength of the leg and trunk musculature is more prominent in rowers than in controls. Nineteen oarsmen and 20 male controls matched for age, height and body mass performed a series of isokinetic and isometric strength tests on an isokinetic dynamometer. These strength tests focused on the trunk and leg muscles. Comparisons of strength were made between and within groups for right and left symmetry patterns, hamstring: quadriceps ratios, and trunk flexor and extensor ratios. The results revealed no left and right asymmetries in either the knee extensor or flexor strength parameters (including both isometric and isokinetic measures). Knee extensor strength was significantly greater in the rowing population, but knee flexor strength was similar between the two groups. No difference was seen between the groups for the hamstring: quadriceps strength ratio. In the rowing population, stroke side had no influence on leg strength. No differences were observed in the isometric strength of the trunk flexors and extensors between groups, although EMG activity was significantly higher in the rowing population. Patterns of asymmetry of muscle activity were observed between the left and right erector spinae muscles during extension, which was significantly related to rowing side (P low back pain in oarsmen.

  1. Trunk Stability, Trunk Strength and Sport Performance Level in Judo.

    Directory of Open Access Journals (Sweden)

    David Barbado

    Full Text Available Although trunk muscle function has been suggested to be a determinant of judo performance, its contribution to high-level performance in this sport has been poorly studied. Therefore, several tests were used to assess the differences in trunk muscle function between 11 international and 14 national level judo practitioners (judokas. Trunk strength and endurance were assessed using isokinetic tests and core stability was assessed using two protocols: 1 sudden loading, to assess trunk responses to unexpected external perturbations; 2 stable and unstable sitting, to assess the participants' ability to control trunk balance. No differences between groups were found for trunk flexor isokinetic strength, trunk responses against lateral and posterior loading and trunk control while sitting. However, international level judokas showed significantly higher trunk extensor isokinetic strength (p <0.05 and lower trunk angular displacement after anterior trunk loading (p <0.05 than national level judokas. Few and low (r < 0.512 significant correlations were found between strength, endurance and stability parameters, which suggests that trunk strength and endurance are not limiting factors for trunk stability in competitive judokas. These results support the importance of trunk extensor strength and trunk stability against forward perturbations in elite judo performance.

  2. Effect of physical training on function of chronically painful muscles: A randomized controlled trial

    DEFF Research Database (Denmark)

    Andersen, Lars L; Andersen, Christoffer H; Zebis, Mette K

    2008-01-01

    .01-0.05). While EMG activity of the unaffected deltoid remained unchanged during the maximal contractions, an increase in EMG amplitude (42-86%, Ppower frequency (19%, Ppainful trapezius muscle. Correspondingly, torque increased 18-53% (P...Purpose: Pain and tenderness of the upper trapezius muscle is frequent in several occupational groups. The objective of this study is to investigate the effect of three contrasting interventions on muscle function and pain in women with trapezius myalgia. Methods: A group of employed women (n=42...... and electromyography (EMG) were recorded during maximal shoulder abductions in an isokinetic dynamometer at -60, 60, 0 and 180 degrees (.)s(-1). Further, a submaximal reference contraction with only the load of the arms was performed. Results: Significant changes were observed only in SST. Pain decreased 42-49% (P

  3. Characteristics of myogenic response and ankle torque recovery after lengthening contraction-induced rat gastrocnemius injury

    Directory of Open Access Journals (Sweden)

    Song Hongsun

    2012-10-01

    Full Text Available Abstract Background Although muscle dysfunction caused by unfamiliar lengthening contraction is one of most important issues in sports medicine, there is little known about the molecular events on regeneration process. The purpose of this study was to investigate the temporal and spatial expression patterns of myogenin, myoD, pax7, and myostatin after acute lengthening contraction (LC-induced injury in the rat hindlimb. Methods We employed our originally developed device with LC in rat gastrocnemius muscle (n = 24. Male Wistar rats were anesthetized with isoflurane (aspiration rate, 450 ml/min, concentration, 2.0%. The triceps surae muscle of the right hindlimb was then electrically stimulated with forced isokinetic dorsi-flexion (180°/sec and from 0 to 45°. Tissue contents of myoD, myogenin, pax7, myostatin were measured by western blotting and localizations of myoD and pax7 was measured by immunohistochemistry. After measuring isometric tetanic torque, a single bout of LC was performed in vivo. Results The torque was significantly decreased on days 2 and 5 as compared to the pre-treatment value, and recovered by day 7. The content of myoD and pax7 showed significant increases on day 2. Myogenin showed an increase from day 2 to 5. Myostatin on days 5 and 7 were significantly increased. Immunohistochemical analysis showed that myoD-positive/pax7-positive cells increased on day 2, suggesting that activated satellite cells play a role in the destruction and the early recovery phases. Conclusion We, thus, conclude that myogenic events associate with torque recovery after LC-induced injury.

  4. Effects of functional exercise training on performance and muscle strength after meniscectomy

    DEFF Research Database (Denmark)

    Ericsson, Y B; Dahlberg, L E; Roos, E M

    2008-01-01

    Muscular deficits and functional limitations have been found years after meniscectomy of the knee. The purpose of this randomized controlled trial was to examine the effect of functional exercise training on functional performance and isokinetic thigh muscle strength in middle-aged patients...... subsequent to meniscectomy for a degenerative tear. Four years after meniscectomy, 45 patients (29 men, 16 women) were randomized to functional exercise training, supervised by a physical therapist, three times weekly for 4 months or to no intervention. The exercise program comprised of postural stability...... training and functional strength and endurance exercises for leg and trunk muscles. Outcomes were three functional performance tests and isokinetic muscle strength. Thirty patients (16 exercisers/14 controls) completed the study. Compared with control patients, the exercise group showed significant...

  5. Fatigue affects peak joint torque angle in hamstrings but not in quadriceps.

    Science.gov (United States)

    Coratella, Giuseppe; Bellin, Giuseppe; Beato, Marco; Schena, Federico

    2015-01-01

    Primary aim of this study was to investigate peak joint torque angle (i.e. the angle of peak torque) changes recorded during an isokinetic test before and after a fatiguing soccer match simulation. Secondarily we want to investigate functional Hecc:Qconc and conventional Hconc:Qconc ratio changes due to fatigue. Before and after a standardised soccer match simulation, twenty-two healthy male amateur soccer players performed maximal isokinetic strength tests both for hamstrings and for quadriceps muscles at 1.05 rad · s(‒1), 3.14 rad · s(‒1) and 5.24 rad · s(‒1). Peak joint torque angle, peak torque and both functional Hecc:Qconc and conventional Hconc:Qconc ratios were examined. Both dominant and non-dominant limbs were tested. Peak joint torque angle significantly increased only in knee flexors. Both eccentric and concentric contractions resulted in such increment, which occurred in both limbs. No changes were found in quadriceps peak joint torque angle. Participants experienced a significant decrease in torque both in hamstrings and in quadriceps. Functional Hecc:Qconc ratio was lower only in dominant limb at higher velocities, while Hconc:Qconc did not change. This study showed after specific fatiguing task changes in hamstrings only torque/angle relationship. Hamstrings injury risk could depend on altered torque when knee is close to extension, coupled with a greater peak torque decrement compared to quadriceps. These results suggest the use eccentric based training to prevent hamstrings shift towards shorter length.

  6. Single point aerosol sampling: Evaluation of mixing and probe performance in a nuclear stack

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, J.C.; Fairchild, C.I.; Wood, G.O. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-02-01

    Alternative Reference Methodologies (ARMs) have been developed for sampling of radionuclides from stacks and ducts that differ from the methods required by the U.S. EPA. The EPA methods are prescriptive in selection of sampling locations and in design of sampling probes whereas the alternative methods are performance driven. Tests were conducted in a stack at Los Alamos National Laboratory to demonstrate the efficacy of the ARMs. Coefficients of variation of the velocity tracer gas, and aerosol particle profiles were determined at three sampling locations. Results showed numerical criteria placed upon the coefficients of variation by the ARMs were met at sampling stations located 9 and 14 stack diameters from flow entrance, but not at a location that is 1.5 diameters downstream from the inlet. Experiments were conducted to characterize the transmission of 10 {mu}m aerodynamic equivalent diameter liquid aerosol particles through three types of sampling probes. The transmission ratio (ratio of aerosol concentration at the probe exit plane to the concentration in the free stream) was 107% for a 113 L/min (4-cfm) anisokinetic shrouded probe, but only 20% for an isokinetic probe that follows the EPA requirements. A specially designed isokinetic probe showed a transmission ratio of 63%. The shrouded probe performance would conform to the ARM criteria; however, the isokinetic probes would not.

  7. Weekly Time Course of Neuro-Muscular Adaptation to Intensive Strength Training.

    Science.gov (United States)

    Brown, Niklas; Bubeck, Dieter; Haeufle, Daniel F B; Weickenmeier, Johannes; Kuhl, Ellen; Alt, Wilfried; Schmitt, Syn

    2017-01-01

    Detailed description of the time course of muscular adaptation is rarely found in literature. Thus, models of muscular adaptation are difficult to validate since no detailed data of adaptation are available. In this article, as an initial step toward a detailed description and analysis of muscular adaptation, we provide a case report of 8 weeks of intense strength training with two active, male participants. Muscular adaptations were analyzed on a morphological level with MRI scans of the right quadriceps muscle and the calculation of muscle volume, on a voluntary strength level by isometric voluntary contractions with doublet stimulation (interpolated twitch technique) and on a non-voluntary level by resting twitch torques. Further, training volume and isokinetic power were closely monitored during the training phase. Data were analyzed weekly for 1 week prior to training, pre-training, 8 weeks of training and 2 weeks of detraining (no strength training). Results show a very individual adaptation to the intense strength training protocol. While training volume and isokinetic power increased linearly during the training phase, resting twitch parameters decreased for both participants after the first week of training and stayed below baseline until de-training. Voluntary activation level showed an increase in the first 4 weeks of training, while maximum voluntary contraction showed only little increase compared to baseline. Muscle volume increased for both subjects. Especially training status seemed to influence the acute reaction to intense strength training. Fatigue had a major influence on performance and could only be overcome by one participant. The results give a first detailed insight into muscular adaptation to intense strength training on various levels, providing a basis of data for a validation of muscle fatigue and adaptation models.

  8. Effects of knee and ankle muscle fatigue on postural control in the unipedal stance.

    Science.gov (United States)

    Bizid, Riadh; Margnes, Eric; François, Yrieix; Jully, Jean Louis; Gonzalez, Gerard; Dupui, Philippe; Paillard, Thierry

    2009-06-01

    The aim of this study was to compare the effects of acute muscle fatigue of the ankle and knee musculature on postural control by immediate measures after performing fatiguing tasks (POST condition). One group of subjects (n = 8) performed a fatiguing task by voluntary contractions of the triceps surae (group TRI) and the other (n = 9) performed a fatiguing task by voluntary contractions of the quadriceps femoris (group QUA). Each muscle group was exercised until the loss of maximal voluntary contraction torque reached 50% (isokinetic dynamometer). Posture was assessed by measuring the centre of foot pressure (COP) with a force platform during a test of unipedal quiet standing posture with eyes closed. Initially (in PRE condition), the mean COP velocity was not significantly different between group TRI and group QUA. In POST condition, the mean COP velocity increased more in group QUA than in group TRI. The postural control was more impaired by knee muscle fatigue than by ankle muscle fatigue.

  9. Browse Title Index

    African Journals Online (AJOL)

    South African Journal for Research in Sport, Physical Education and Recreation. ... of isokinetic leg strength in professional soccer and basketball players, Abstract ... Vol 39, No 3 (2017), Comparisons of performance indicators between Super ...

  10. Isokinetic Hamstrings: Quadriceps Ratios in Intercollegiate Athletes.

    Science.gov (United States)

    Rosene, John M.; Fogarty, Tracey D.; Mahaffey, Brian L.

    2001-01-01

    Compared the differences in the concentric hamstrings to quadriceps (H:Q) ratio among athletes in different sports at three velocities. Measurement of H:Q ratio of both knees among male and female college athletes indicated that the H:Q ratio increased as velocity increased. No differences existed for the H:Q ratio for sport or side of body. (SM)

  11. 40 CFR 60.675 - Test methods and procedures.

    Science.gov (United States)

    2010-07-01

    ... distance between the observer and the emission source shall be 4.57 meters (15 feet). (ii) The observer... isokinetic sampling rates. ER28AP09.007 Where: Ve = average building vent velocity (feet per minute); Qf...

  12. Análise isocinética da articulação do cotovelo em crianças com paralisia cerebral Isokinetic analysis of the elbow joint in children with cerebral palsy

    Directory of Open Access Journals (Sweden)

    Patrícia Martins Franciulli

    2012-03-01

    Full Text Available A quantidade de torque aplicado na articulação é uma medida de aptidão física importante para crianças com paralisia cerebral. O presente estudo analisou parâmetros cinéticos na articulação do cotovelo em crianças saudáveis e com paralisia cerebral. Participaram 10 crianças com paralisia cerebral e 10 crianças sem comprometimento neurológico. Avaliou-se a média do pico de torque, média do ângulo do pico de torque, coeficiente de variação do torque e aceleração angular do movimento de flexo-extensão do cotovelo nas velocidades com um dinamômetro isocinético. A média de pico de torque (extensão, aceleração (flexão e coeficiente de variação (flexão e extensão são diferentes entre grupos. Conclui-se que o torque e aceleração sofreram interferências no movimento de flexo-extensão; as principais diferenças encontradas foram entre os extremos das velocidades; não houve diferenças no ângulo do pico de torque. A espasticidade não interferiu na força dos músculos agonistas do movimento de flexão da articulação do cotovelo.The joint torque is an important variable related to children with cerebral palsy. The present study analyzed kinetic parameters during elbow flexion and extension movements in healthy and cerebral palsy children. Ten healthy and 10 cerebral palsy children participated of the study. An isokinetic dynamometer was used to measure the elbow mean peak torque, mean angle peak torque, coefficient of variation and acceleration during flexion and extension movements at different angular speeds. The mean peak torque on extension movement in healthy children group was significant higher compared to the cerebral palsy group. The coefficient of variation on both flexion and extension movements was significantly higher in cerebral palsy group. However there were significantly difference on both groups compared the lowest and highest velocities. Although the results showed no difference in flexor peak

  13. Experimental knee joint pain during strength training and muscle strength gain in healthy subjects: a randomized controlled trial.

    Science.gov (United States)

    Sørensen, T J; Langberg, H; Hodges, P W; Bliddal, H; Henriksen, M

    2012-01-01

    Knee joint pain and reduced quadriceps strength are cardinal symptoms in many knee pathologies. In people with painful knee pathologies, quadriceps exercise reduces pain, improves physical function, and increases muscle strength. A general assumption is that pain compromises muscle function and thus may prevent effective rehabilitation. This study evaluated the effects of experimental knee joint pain during quadriceps strength training on muscle strength gain in healthy individuals. Twenty-seven healthy untrained volunteers participated in a randomized controlled trial of quadriceps strengthening (3 times per week for 8 weeks). Participants were randomized to perform resistance training either during pain induced by injections of painful hypertonic saline (pain group, n = 13) or during a nonpainful control condition with injection of isotonic saline (control group, n = 14) into the infrapatellar fat pad. The primary outcome measure was change in maximal isokinetic muscle strength in knee extension/flexion (60, 120, and 180 degrees/second). The group who exercised with pain had a significantly larger improvement in isokinetic muscle strength at all angular velocities of knee extension compared to the control group. In knee flexion there were improvements in isokinetic muscle strength in both groups with no between-group differences. Experimental knee joint pain improved the training-induced gain in muscle strength following 8 weeks of quadriceps training. It remains to be studied whether knee joint pain has a positive effect on strength gain in patients with knee pathology. Copyright © 2012 by the American College of Rheumatology.

  14. The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days local muscle unloading.

    Science.gov (United States)

    Weber, Tobias; Ducos, Michel; Mulder, Edwin; Beijer, Åsa; Herrera, Frankyn; Zange, Jochen; Degens, Hans; Bloch, Wilhelm; Rittweger, Jörn

    2014-05-01

    In the light of the dynamic nature of habitual plantar flexor activity, we utilized an incremental isokinetic exercise test (IIET) to assess the work-related power deficit (WoRPD) as a measure for exercise-induced muscle fatigue before and after prolonged calf muscle unloading and in relation to arterial blood flow and muscle perfusion. Eleven male subjects (31 ± 6 years) wore the HEPHAISTOS unloading orthosis unilaterally for 56 days. It allows habitual ambulation while greatly reducing plantar flexor activity and torque production. Endpoint measurements encompassed arterial blood flow, measured in the femoral artery using Doppler ultrasound, oxygenation of the soleus muscle assessed by near-infrared spectroscopy, lactate concentrations determined in capillary blood and muscle activity using soleus muscle surface electromyography. Furthermore, soleus muscle biopsies were taken to investigate morphological muscle changes. After the intervention, maximal isokinetic torque was reduced by 23·4 ± 8·2% (Pflow, tissue oxygenation, lactate concentrations and EMG median frequency kinematics during the exercise test were comparable before and after the intervention, whereas the increase of RMS in response to IIET was less following the intervention (P = 0·03). In conclusion, following submaximal isokinetic muscle work exercise-induced muscle fatigue is unaffected after prolonged local muscle unloading. The observation that arterial blood flow was maintained may underlie the unchanged fatigability. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  15. Effects of Lifestyle on Muscle Strength in a Healthy Danish Population

    DEFF Research Database (Denmark)

    Bartels, Else Marie; Robertson, Samuel; Danneskiold-Samsøe, Bente

    2018-01-01

    The Copenhagen City Heart Study (CCHS) and measurements of Isokinetic muscle strength from a sub-study of randomly selected healthy participants from CCHS. Methods: 126 women and 63 men were studied. All participants completed a questionnaire regarding their lifestyle, including physical activity, alcohol intake...... in the lower extremities (p = 0.03) for women, and lower extremities (p = 0.03) and trunk (p = 0.007) for men. Alcohol Intake was in general not correlated to muscle strength. No clear effect of smoking was seen on muscle strength. Conclusion: Our results show that physical activity during leisure...... and smoking habits. Isokinetic muscle strength was measured over the upper extremities (UE), trunk, and lower extremities (LE). Multivariate analyses including all of the variables were carried out. Results: The level of daily physical activity during leisure was positively correlated to muscle strength...

  16. Effects of Lifestyle on Muscle Strength in a Healthy Danish Population

    DEFF Research Database (Denmark)

    Bartels, Else Marie; Robertson, Samuel; Danneskiold-Samsøe, Bente

    2018-01-01

    The Copenhagen City Heart Study (CCHS) and measurements of Isokinetic muscle strength from a sub-study of randomly selected healthy participants from CCHS. Methods: 126 women and 63 men were studied. All participants completed a questionnaire regarding their lifestyle, including physical activity, alcohol intake...... in the lower extremities (p = 0.03) for women, and lower extremities (p = 0.03) and trunk (p = 0.007) for men. Alcohol Intake was in general not correlated to muscle strength. No clear effect of smoking was seen on muscle strength. Conclusions: Our results show that physical activity during leisure...... and smoking habits. Isokinetic muscle strength was measured over the upper extremities (UE), trunk, and lower extremities (LE). Multivariate analyses including all of the variables were carried out. Results: The level of daily physical activity during leisure was positively correlated to muscle strength...

  17. Subcutaneous immunoglobulin preserves muscle strength in chronic inflammatory demyelinating polyneuropathy

    DEFF Research Database (Denmark)

    Markvardsen, Lars Høj; Harbo, Thomas; Sindrup, Søren Hein

    2014-01-01

    evaluated after 3, 6 and 12 months. Primary end-points were changes in muscle strength evaluated by isokinetic dynamometry in four affected muscle groups and a composite score of muscle performance and function tests, including Medical Research Council (MRC) score, grip strength, 40-m walking test (40-MWT......BACKGROUND AND PURPOSE: Subcutaneous immunoglobulin (SCIG) is superior to placebo treatment for maintenance of muscle strength during 12 weeks in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). The present study evaluated whether SCIG preserves muscle strength for 1 year......) and nine-hole peg test (9-HPT). Secondary end-points were changes of each of the listed parameters at each time point as well as an overall disability sum score (ODSS). RESULTS: The dose of SCIG was significantly unaltered during the follow-up period. Overall the isokinetic dynamometry value increased by 7...

  18. Torque and mechanomyogram relationships during electrically-evoked isometric quadriceps contractions in persons with spinal cord injury.

    Science.gov (United States)

    Ibitoye, Morufu Olusola; Hamzaid, Nur Azah; Hasnan, Nazirah; Abdul Wahab, Ahmad Khairi; Islam, Md Anamul; Kean, Victor S P; Davis, Glen M

    2016-08-01

    The interaction between muscle contractions and joint loading produces torques necessary for movements during activities of daily living. However, during neuromuscular electrical stimulation (NMES)-evoked contractions in persons with spinal cord injury (SCI), a simple and reliable proxy of torque at the muscle level has been minimally investigated. Thus, the purpose of this study was to investigate the relationships between muscle mechanomyographic (MMG) characteristics and NMES-evoked isometric quadriceps torques in persons with motor complete SCI. Six SCI participants with lesion levels below C4 [(mean (SD) age, 39.2 (7.9) year; stature, 1.71 (0.05) m; and body mass, 69.3 (12.9) kg)] performed randomly ordered NMES-evoked isometric leg muscle contractions at 30°, 60° and 90° knee flexion angles on an isokinetic dynamometer. MMG signals were detected by an accelerometer-based vibromyographic sensor placed over the belly of rectus femoris muscle. The relationship between MMG root mean square (MMG-RMS) and NMES-evoked torque revealed a very high association (R(2)=0.91 at 30°; R(2)=0.98 at 60°; and R(2)=0.97 at 90° knee angles; Ptorque, between 0.65 and 0.79 for MMG-RMS, and from 0.67 to 0.73 for MMG-PTP. Their standard error of measurements (SEM) ranged between 10.1% and 31.6% (of mean values) for torque, MMG-RMS and MMG-PTP. The MMG peak frequency (MMG-PF) of 30Hz approximated the stimulation frequency, indicating NMES-evoked motor unit firing rate. The results demonstrated knee angle differences in the MMG-RMS versus NMES-isometric torque relationship, but a similar torque related pattern for MMG-PF. These findings suggested that MMG was well associated with torque production, reliably tracking the motor unit recruitment pattern during NMES-evoked muscle contractions. The strong positive relationship between MMG signal and NMES-evoked torque production suggested that the MMG might be deployed as a direct proxy for muscle torque or fatigue measurement during

  19. Pneumatic muscle actuator for resistive exercise in microgravity: test with a leg model.

    Science.gov (United States)

    Serres, Jennifer L; Phillips, Chandler A; Reynolds, David B; Mohler, Stanley R; Rogers, Dana B; Repperger, Daniel W; Gerschutz, Maria J

    2010-02-01

    A proof-of-concept demonstration is described in which a DC servomotor (simulating the quadriceps of a human operator) rotated a pulley 90 degrees (simulating knee extension). A pneumatic muscle actuator (PMA) generated an opposing force (antagonist) to the rotating pulley. One application of such a device is for use in microgravity environments because the PMA is compact, simple, and of relatively small mass (283 g). In addition, the operator can set a computer-controlled force-level range in response to individual user changes in exercise conditioning over time. A PMA was used in this study and interacted with a DC servomotor. For each trial, the PMA contracted in response to internal pressure. An input voltage profile activated the DC servomotor, resulting in the following three phases: an isokinetic counterclockwise pulley rotation of 90 degrees over 5 s (Phase I), the position was held for 5 s (Phase II), and an isokinetic clockwise rotation of 90 degrees over 5 s (Phase III). Root mean square error (RMSE) values were used to evaluate the pulley rotation. For Phase I, when the PMA pressures (in kPa) were 300, 450, and 575, the percent RMSE, respectively, were 5.24, 6.23, and 4.59. For Phase II, the percent RMSE were 2.81, 2.57, and 5.63, respectively. For Phase III, the percent RMSE were 5.69, 2.63, and 3.30, respectively. This study presents a demonstration of a PMA device that can enhance exercise by providing a wide range of resistive loads.

  20. Pneumatic muscle actuator (PMA) task-specific resistance for potential use in microgravity exercise.

    Science.gov (United States)

    Hall, Kara L; Phillips, Chandler A; Reynolds, David B; Mohler, Stanley R; Neidhard-Doll, Amy T

    2012-07-01

    A pneumatic muscle actuator (PMA) is a device that mimics the behavior of skeletal muscle by contracting and generating force when activated. This type of actuator has a high power to weight ratio and unique characteristics which make it ideal for human interaction. PMAs, however, are difficult to control due to nonlinear dynamics. Our objective was to control a PMA as a source of task-specific resistance in simulated isokinetic strength training. Task-specific resistance will benefit those in need of strength training through a joint's range of motion, including astronauts who need to counteract muscle atrophy during prolonged spaceflight. The lightweight, clean, and compact PMA driven by pressurized air is able to produce resistance in microgravity. An open-loop control method based on a three-element phenomenological inverse model was developed to control the PMA. A motor was simultaneously controlled to act as simulated human quadriceps working against the PMA-produced resistance. For ankle weight replacement resistance profiles, the PMA control method produced resistance and PMA displacement tracking errors (RMSE) of 0.36-1.61 Nm and 0.55-1.59 mm, respectively. Motor position (simulated joint angle) tracking errors ranged from 0.47 to 2.82 degrees. Results indicate that the inverse model based control system produces task-specific PMA resistance and displacement. Closed-loop motor control was able to simulate isokinetic movement successfully. More complicated resistance profiles reveal the need for closed-loop control. Future work focuses on advancing both the PMA control strategies and the capabilities of the human simulator so that actual human operator applications can be realized.

  1. Browse Title Index

    African Journals Online (AJOL)

    Items 951 - 1000 of 1125 ... Vol 19, No 3 (2013), The effect of knee position on concentric isokinetic .... education programme on knowledge regarding risk factors for chronic ... Vol 18, No 2 (2012), The influence of Corepower training on golfers' ...

  2. Effects of intensive physical rehabilitation on neuromuscular adaptations in adults with poststroke hemiparesis

    DEFF Research Database (Denmark)

    Andersen, Lars L; Zeeman, Peter; Jørgensen, Jørgen R

    2011-01-01

    consisting of isokinetic muscle strength, neuromuscular activation measured with electromyography (EMG), electrically evoked muscle twitch contractile properties, and gait performance (10-m Walk Test and 6-min Walk Test). After the 12-week conditioning program, knee extensor and flexor strength increased...... the effect of intensive physical rehabilitation on neuromuscular and functional adaptations in outpatients suffering from hemiparesis after stroke. A within-subject repeated-measures design with the paretic leg as the experimental leg and the nonparetic leg as the control leg was used. Eleven outpatients...... observed in the nonparetic control leg. Gait performance increased 52-68%. In conclusion, intensive physical rehabilitation after stroke leads to clinically relevant neuromuscular improvements, leading to increased voluntary strength during a wide range of contraction modes and velocities, and improved...

  3. [Effects of Reactive Jump Training in Handball Players Regarding Jump Height and Power Development in the Triceps Surae Muscle].

    Science.gov (United States)

    Rensing, N; Westermann, A; Möller, D; von Piekartz, H

    2015-12-01

    Studies have shown changes in the technical and physical demands in modern handball. The game has increased considerably in speed, power and dynamics. Jump training has, therefore, become ever more important in the training of the athletes. These developments contribute to the fact that handball is now one of the most injury-prone types of sport, with the lower extremities being most frequently affected. Reactive jump training is not only used in training by now, but also increasingly in injury prevention. The aim of this study was to investigate the effectiveness of reactive jump training with handball players. 21 regional league handball players were randomly divided into an intervention group (n = 12) and a control group (n = 9). The intervention group completed a six-week reactive jump training programme while the control group went through a non-specific training programme. Jump height (squat and counter movement jump), isokinetic and isometric maximum power as well as muscle activity served as measuring parameters. A comparison of the intervention and control groups revealed that the reactive jump training led to significant improvements in jump height. The isometric and isokinetic maximum power measurements and the electromyographic activities of the triceps surae muscle demonstrated an improvement in the values within the intervention group. However, this improvement was not significant compared with the control group. Likewise both jumps correlated with the muscle activity of the soleus muscle as shown by electromyography. A moderate correlation was noticed between the isokinetic maximum power measurement and the electromyographic activity of the soleus and gastrocnemius medialis muscles. Furthermore, the correlations of the isometric and isokinetic maximum power meas-urements resulted in a strong correlation coefficient. This study revealed a significant increase in jump height after reactive jump training. There was no significant difference in

  4. Differential Effects of 2 Rehabilitation Programs Following Anterior Cruciate Ligament Reconstruction

    DEFF Research Database (Denmark)

    Setuain, Igor; Izquierdo, Mikel; Idoate, Fernando

    2017-01-01

    in their recovery according to the current evidence-based principles. UCR group followed the national conventional approach for ACL rehabilitation. Main Outcome Measures- Concentric isokinetic knee joint flexor-extension torque assessments at 180º/s and Magnetic Resonance Imaging (MRI) evaluations were performed...

  5. Characterisation of a pneumatic muscle test station with two dynamic plants in cascade.

    Science.gov (United States)

    Serres, J L; Reynolds, D B; Phillips, C A; Rogers, D B; Repperger, D W

    2010-02-01

    Pneumatic muscle actuators (PMAs) offer significant advantages over more traditional actuators, which make them prime candidates in rehabilitation devices. A dynamic test station (DTS) is modified to demonstrate the use of a PMA for this application. The DTS includes two dynamic systems: a PMA and a DC servomotor. An overall transfer function was developed utilising characterisation data for the PMA and DC servomotor. A Tustin (bilinear) transform was performed on the overall transfer function to obtain a discrete time system. Model parameters were optimised and used to generate input voltage profiles that achieve isokinetic (constant velocity) task specifications. Percent root mean square error values (PRMSE) between the actual and ideal profiles were used to evaluate the accuracy of this method in achieving isokinetic displacement. For PMA pressures (in kPa) of 150, 350 and 550 PRMSE were 7.80, 5.40 and 2.76, respectively.

  6. Characteristics of upper limb muscular strength in male wheelchair tennis players

    Science.gov (United States)

    Moon, Hyo-Bin; Park, Seung-Jae; Kim, Al-Chan; Jang, Jee-Hun

    2013-01-01

    The purpose of this study was to identify the characteristics of muscular strength in upper limb and to present the preliminary information for development of sports injury prevention program and exercise rehabilitation program in wheelchair tennis players. Participants were 12 male wheelchair tennis players. Muscular strength was measured in shoulder and elbow joints with isokinetic dynamometer. Ipsilateral (IR) and bilateral (BR) balance ratio were calculated with isokinetic strength at 60°/sec. As a result, extension strength (ES) was significantly higher than flexion strength (FS) (Pelbow joint FS was significantly higher than ES (Pelbow joints and lower IR and BR in elbow joints could be the characteristics in male wheelchair tennis players. It is suggested that flexor strengthening program in nondominant shoulder joint, extensor strengthening program in both elbow joint, and flexor strengthening program in non-dominant elbow joint should be introduced for male wheelchair tennis players. PMID:24278887

  7. Exercise countermeasures for bed-rest deconditioning

    Science.gov (United States)

    Greenleaf, John (Editor)

    1993-01-01

    The purpose for this 30-day bed rest study was to investigate the effects of short-term, high intensity isotonic and isokinetic exercise training on maintenance of working capacity (peak oxygen uptake), muscular strength and endurance, and on orthostatic tolerance, posture and gait. Other data were collected on muscle atrophy, bone mineralization and density, endocrine analyses concerning vasoactivity and fluid-electrolyte balance, muscle intermediary metabolism, and on performance and mood of the subjects. It was concluded that: The subjects maintained a relatively stable mood, high morale, and high esprit de corps throughout the study. Performance improved in nearly all tests in almost all the subjects. Isotonic training, as opposed to isokinetic exercise training, was associated more with decreasing levels of psychological tension, concentration, and motivation; and improvement in the quality of sleep. Working capacity (peak oxygen uptake) was maintained during bed rest with isotonic exercise training; it was not maintained with isokinetic or no exercise training. In general, there was no significant decrease in strength or endurance of arm or leg muscles during bed rest, in spite of some reduction in muscle size (atrophy) of some leg muscles. There was no effect of isotonic exercise training on orthostasis, since tilt-table tolerance was reduced similarly in all three groups following bed rest. Bed rest resulted in significant decreases of postural stability and self-selected step length, stride length, and walking velocity, which were not influenced by either exercise training regimen. Most pre-bed rest responses were restored by the fourth day of recovery.

  8. Fatigue reduction during aggregated and distributed sequential stimulation.

    Science.gov (United States)

    Bergquist, Austin J; Babbar, Vishvek; Ali, Saima; Popovic, Milos R; Masani, Kei

    2017-08-01

    Transcutaneous neuromuscular electrical stimulation (NMES) can generate muscle contractions for rehabilitation and exercise. However, NMES-evoked contractions are limited by fatigue when they are delivered "conventionally" (CONV) using a single active electrode. Researchers have developed "sequential" (SEQ) stimulation, involving rotation of pulses between multiple "aggregated" (AGGR-SEQ) or "distributed" (DISTR-SEQ) active electrodes, to reduce fatigue (torque-decline) by reducing motor unit discharge rates. The primary objective was to compare fatigue-related outcomes, "potentiation," "variability," and "efficiency" between CONV, AGGR-SEQ, and DISTR-SEQ stimulation of knee extensors in healthy participants. Torque and current were recorded during testing with fatiguing trains using each NMES type under isometric and isokinetic (180°/s) conditions. Compared with CONV stimulation, SEQ techniques reduced fatigue-related outcomes, increased potentiation, did not affect variability, and reduced efficiency. SEQ techniques hold promise for reducing fatigue during NMES-based rehabilitation and exercise; however, optimization is required to improve efficiency. Muscle Nerve 56: 271-281, 2017. © 2016 Wiley Periodicals, Inc.

  9. Body Mass Bias in a Combat Fitness Test

    Science.gov (United States)

    2011-02-07

    Allometric scaling of isokinetic peak torque: The Nebraska Wrestling Study. European Journal of Applied Physiology, 80, 240–248. White, C. R...applied to the Movement and 3-mi run times after converting times to velocity (in meters ). The estimated metabolic rate mass coefficients were

  10. KNEE ISOKINETIC TORQUE IMBALANCE IN FEMALE FUTSAL PLAYERS

    Directory of Open Access Journals (Sweden)

    Ana Carolina de Mello Alves Rodrigues

    Full Text Available ABSTRACT Introduction: The specificity of sports training can lead to muscle specialization with a possible change in the natural hamstring/quadriceps torque ratio (HQ ratio, constituting a risk factor for muscle injury at the joint angles in which muscle imbalance may impair dynamic stability. Objective: The aim was to evaluate the torque distribution of the hamstrings and quadriceps and the HQ ratio throughout the range of motion in order to identify possible muscle imbalances at the knee of female futsal athletes. Methods: Nineteen amateur female futsal athletes had their dominant limb HQ ratio evaluated in a series of five maximum repetitions of flexion/extension of the knee at 180°/second in the total joint range of motion (30° to 80°. The peak flexor and extensor torque and the HQ ratio (% were compared each 5° of knee motion using one-way repeated measures ANOVA and Tukey’s post hoc test (p<0.05 to determine the joint angles that present muscular imbalance. Results: Quadriceps torque was higher than 50° to 60° of knee flexion, while hamstrings torque was higher than 55° to 65°. The HQ ratio presented lower values than 30° to 45° of knee flexion and four athletes presented values lower than 60%, which may represent a risk of injury. However, the HQ ratio calculated by the peak torque showed only one athlete with less than 60%. Conclusion: The HQ ratio analyzed throughout the knee range of motion allowed identifying muscle imbalance at specific joint angles in female futsal players.

  11. Thoracic posture, shoulder muscle activation patterns and isokinetic ...

    African Journals Online (AJOL)

    Shoulder injuries are the most severe injuries in rugby union players, accounting for almost 20% of ... under demanding circumstances such as participation in sport.[6,7] ..... from a biomechanical point of view, especially in the game of rugby.

  12. Enthalpy–entropy compensation and the isokinetic temperature in ...

    Indian Academy of Sciences (India)

    Athel Cornish-Bowden

    2017-11-07

    Nov 7, 2017 ... (1964) drew attention to the possibility that statistical arte- facts might ... effects were caused by 'a ubiquitous property of water'. (Lumry and ..... design of potent and isozyme-selective inhibitors of the enzyme. Biochemistry 53 ...

  13. Strength Training. A Key to Athletic Training.

    Science.gov (United States)

    Whiteside, Patricia W.

    Characteristics of an effective strength training program are analyzed and descriptions are offered of different kinds of weight training activities. Comparisons are made between concentric, isometric, eccentric, and isokinetic training methods. The fundamentals and techniques of an exemplary training program are outlined and the organization and…

  14. Effect of a Short Time Concentric Versus Eccentric Training Program on Electromyography Activity and Peak Torque of Quadriceps

    DEFF Research Database (Denmark)

    Carvalho, Alberto; Caserotti, Paolo; Carvalho, C.

    2014-01-01

    The purpose of this study was to examine the effect of an 8-week concentric (CON) versus eccentric (ECC) isokinetic training program on the electromyography (EMG) signal amplitude of vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF). Also, the isometric (ISO) and dynamic maximum...

  15. Influence of muscle geometry on shortening speed of fibre, aponeurosis and muscle

    NARCIS (Netherlands)

    Zuurbier, C. J.; Huijing, P. A.

    1992-01-01

    The influence of muscle geometry on muscle shortening of the gastrocnemius medialis muscle (GM) of the rat was studied. Using cinematography, GM geometry was studied during isokinetic concentric activity at muscle lengths ranging from 85 to 105% of the optimum muscle length. The shortening speed of

  16. Influence of Anterior Cruciate Ligament Tear on Thigh Muscle Strength and Hamstring-to-Quadriceps Ratio: A Meta-Analysis.

    Science.gov (United States)

    Kim, Hyun-Jung; Lee, Jin-Hyuck; Ahn, Sung-Eun; Park, Min-Ji; Lee, Dae-Hee

    2016-01-01

    Theoretical compensation after anterior cruciate ligament (ACL) tear could cause quadriceps weakness and hamstring activation, preventing anterior tibial subluxation and affecting the expected hamstring-to-quadriceps ratio. Although quadriceps weakness often occurs after ACL tears, it remains unclear whether hamstring strength and hamstring-to-quadriceps ratio increase in ACL deficient knees. This meta-analysis compared the isokinetic muscle strength of quadriceps and hamstring muscles, and the hamstring-to-quadriceps ratio, of the injured and injured limbs of patients with ACL tears. This meta-analysis included all studies comparing isokinetic thigh muscle strengths and hamstring-to-quadriceps ratio in the injured and uninjured legs of patients with ACL tear, without or before surgery. Thirteen studies were included in the meta-analysis. Quadriceps and hamstring strengths were 22.3 N∙m (95% CI: 15.2 to 29.3 N∙m; Pratio was 4% greater in ACL deficient than in uninjured limbs (95% CI: 1.7% to 6.3%; Pratio in ACL deficient knees.

  17. Sensorimotor posture control in the blind: superior ankle proprioceptive acuity does not compensate for vision loss.

    Science.gov (United States)

    Ozdemir, Recep A; Pourmoghaddam, Amir; Paloski, William H

    2013-09-01

    To better understand sensorimotor posture control differences between blind and sighted individuals, we examined the role of ankle joint proprioception and ankle muscle strength on postural control in healthy blind (n=13, 25-58 years) and age- and sex-matched sighted (n=15, 20-65 years) volunteers. We measured ankle joint proprioceptive acuity and isokinetic muscle strength in plantarflexion and dorsiflexion using an isokinetic dynamometer. We also assessed postural control performance during quiet bipedal stance with and without sudden postural perturbations, and during quiet unipedal stance. We found that while our blind subjects exhibited significantly better proprioceptive acuity than our sighted subjects their postural control performance was significantly poorer than that of the sighted group with eyes open, and no different from that of the sighted group with eyes closed suggesting that their superior proprioceptive acuity does not translate to improved balance control. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Long-term interventions effects of robotic training on patients after anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Hu, Chunying; Huang, Qiuchen; Yu, Lili; Zhou, Yue; Gu, Rui; Ye, Miao; Ge, Meng; Xu, Yanfeng; Liu, Jianfeng

    2016-08-01

    [Purpose] The aim of this study was to examine the long-term interventions effects of robot-assisted therapy rehabilitation on functional activity levels after anterior cruciate ligament reconstruction. [Subjects and Methods] The subjects were 8 patients (6 males and 2 females) who received anterior cruciate ligament reconstruction. The subjects participated in robot-assisted therapy lasting for one month. The Timed Up-and-Go test, 10-Meter Walk test, Functional Reach Test, surface electromyography of the vastus lateralis and vastus medialis, and extensor strength of isokinetic movement of the knee joint were evaluated before and after the intervention. [Results] The average value of the of vastus medialis EMG, Functional Reach Test, and the maximum and average extensor strength of the knee joint isokinetic movement increased significantly, and the time of the 10-Meter Walk test decreased significantly. [Conclusion] These results suggest that walking ability and muscle strength can be improved by robotic walking training as a long-term intervention.

  19. Preseason physiological profile of soccer and basketball players in different divisions.

    Science.gov (United States)

    Metaxas, Thomas I; Koutlianos, Nikos; Sendelides, Thomas; Mandroukas, Athanasios

    2009-09-01

    The purpose of this study was to examine and compare the cardiorespiratory performance and isokinetic muscle strength between Greek soccer and basketball players of different divisions before starting the training season. Study participants included 100 soccer players and 61 basketball players, who were assigned according to the kind of sport and division. All participants underwent anthropometric measurements and performed an exercise test on a treadmill to determine maximal oxygen uptake (VO2max). Peak torque for quadriceps and hamstring muscles was measured on isokinetic dynamometer at angular velocity of 60 degrees/s(-1), 180 degrees/s(-1), and 300 degrees/s(-1). The statistical p value was set at p duration of the maintenance period and to the effect of the training session on each sport, respectively. Finally, a higher level of muscle strength would be preferable in soccer and basketball and would reduce the risk for injuries in the maintenance and rebuilding training periods.

  20. A comparison of muscle stiffness and musculoarticular stiffness of the knee joint in young athletic males and females.

    Science.gov (United States)

    Wang, Dan; De Vito, Giuseppe; Ditroilo, Massimiliano; Fong, Daniel T P; Delahunt, Eamonn

    2015-06-01

    The objective of this study was to investigate the gender-specific differences in peak torque (PT), muscle stiffness (MS) and musculoarticular stiffness (MAS) of the knee joints in a young active population. Twenty-two male and twenty-two female recreational athletes participated. PT of the knee joint extensor musculature was assessed on an isokinetic dynamometer, MS of the vastus lateralis (VL) muscle was measured in both relaxed and contracted conditions, and knee joint MAS was quantified using the free oscillation technique. Significant gender differences were observed for all dependent variables. Females demonstrated less normalized PT (mean difference (MD)=0.4Nm/kg, p=0.005, η(2)=0.17), relaxed MS (MD=94.2N/m, pjoint injury incidence and prevalence in females when compared to males. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Evaluation of Intake Efficiencies and Associated Sediment-Concentration Errors in US D-77 Bag-Type and US D-96-Type Depth-Integrating Suspended-Sediment Samplers

    Science.gov (United States)

    Sabol, T. A.; Topping, D. J.; Griffiths, R. E.

    2011-12-01

    Accurate measurements of suspended-sediment concentration require suspended-sediment samplers to operate isokinetically with an intake-efficiency of 1.0 ± 0.10. Results from 1940s Federal Interagency Sedimentation Project (FISP) laboratory experiments show that when the intake efficiency does not equal 1.0, suspended-sediment samplers either under- or oversample sediment relative to water, leading to biases in suspended-sediment concentration. The majority of recent FISP sampler development and testing has been conducted under uniform flow conditions using flume and slack-water tow tests, with little testing in actual turbulent rivers. Recent work has focused on the hydraulic characteristics and intake efficiencies of these samplers, without field investigations of the accuracy of the suspended-sediment data collected with these samplers. When depth-integrating suspended-sediment samplers are deployed under the non-uniform and turbulent conditions that exist in rivers, multiple factors may contribute to departures from isokinetic sampling. This introduces errors into the suspended-sediment data that may not be predictable on the basis of flume and tow tests alone. This study (1) evaluates the intake efficiencies of the older US D-77 bag-type and newer, FISP-approved US D-96 samplers at multiple river cross sections under a range of flow conditions; (2) examines if water temperature and sampling duration explain measured differences in intake efficiency between samplers and between laboratory and field tests; (3) models and predicts the directions and magnitudes of errors in measured suspended-sand concentration; and (4) determines if the relative differences in suspended-sediment concentration in a variety of size classes are consistent with the differences expected on the basis of the 1940s FISP-laboratory experiments. Results indicate that under river conditions, the intake efficiency of the US D-96 sampler is superior to that of the US D-77 bag-type sampler and

  2. Abstracts of Research Project Reports by Naval Dental Clinic First- and Second-Year Residents - June 1983.

    Science.gov (United States)

    1983-12-01

    W6 1 December 193 TECHNICAL REPORT 111/ 0 ’I~u ABSTRACTS OF RESEARCH PROJECT REPORTS BY NAVAL DENTAL CLZUC IRST- AND SEcon-TEu RESIDENTS - JUNE 1983 by...no signs, symptoms, or history of myofascial pain dysfunction syndrome, temporomandibular joint dysfunction, or posterior bite collapse. An isokinetic

  3. Strength and energetics of elite rugby union players | Lombard ...

    African Journals Online (AJOL)

    The greater absolute strength spectrum (p < 0.05) measured on an isokinetic dynamometer for quadriceps and hamstring muscles of elite backs and forwards, confirmed the acquisition of strength for elite performance. The elite backs and forwards did not possess greater quadriceps and hamstring endurance (p < 0.05) than ...

  4. Construct Validity of Physical Fitness Tests

    Science.gov (United States)

    2011-02-03

    Powers, S. K., Lawler, J., Ayers, D., & Stuart, M. K. (1991). Physiological correlates to 800 meter running performance. Journal of Sports Medicine and... isokinetic tests. Journal of Sports Medicine and Physical Fitness, 36, 169-177. *Myers, D. C., Gebhardt, D. L., Crump, C.E., & Fleishman, E. A. (1984

  5. Asymmetry of Muscle Strength in Elite Athletes

    Science.gov (United States)

    Drid, Patrik; Drapsin, Miodrag; Trivic, Tatjana; Lukac, Damir; Obadov, Slavko; Milosevic, Zoran

    2009-01-01

    "Study aim": To determine muscle strength variables in elite judoists and wrestlers since thigh muscle strength and bilaterally balanced flexor-to-extensor ratio minimise injury risk and are desirable for achieving sport successes. "Material and methods": Judoists, wrestlers and untrained subjects, 10 each, were subjected to isokinetic strength…

  6. The Effect of Fatigue in Proxmal and Distal Muscles of Lower Extremity on Postural Control

    Directory of Open Access Journals (Sweden)

    Mozhgan Moghadam

    2003-07-01

    Full Text Available Objective: Several studies have shown the effects of muscular fatigue on proprioception and neuromuscular control. However all available researches have studied just the effect of local fatigue in ankle joint muscles on postural control, and no study have found about the effect of fatigue in proximal muscles of the lower extremity on postural control. To compare changes in postural control parameters after isokinetic fatigue of proximal and distal muscles of lower extremity. Materials & Methods: Subjects were twenty healthy men (age: 22.6±2.4 years, height: 173.7± 3.6 cm, weight: 63.3±7.9kg. There were 4 test sessions, with a randomized order according to site and plane of fatigue. During each session one of these muscle groups was fatigued using a Biodex isokinetic dynamometer: ankle plantar / dorsi flexors, ankle evertor / inventors, hip flexor / extensors and hip abductor/adductors. The biodex stability system was used to perform dynamic balance test before and after muscle fatigue in each session. Overall, anterior / posterior, and medial/lateral stability indices were recorded. The higher the stability indices, the lower the balancing skill. Results: Analysis of pre-and post fatigue balance results of all sessions, demonstrated significant increase (P<0.05 in all stability indices. Repeated measures ANOVA performed on the rate of changes in stability indices during each session revealed that hip muscle fatigue caused much more increase in stability indices than ankle muscle fatigue (P<0.05. Conclusion: Isokinetic fatigue of both ankle and hip muscles significantly decreases postural control ability in healthy young men. In addition, our findings suggest that the hip joint musculature plays a more prominent role in postural control.

  7. Relationship between vitamin D and lung function, physical performance and balance on patients with stage I-III chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Tuncay Yumrutepe

    2015-04-01

    Full Text Available Summary Objectives: vitamin D is important for muscle function and it affects different aspects of muscle metabolism. This study aim to determine whether serum 25(OH D levels are related to lung functions, physical performance and balance in patients with chronic obstructive pulmonary disease (COPD. Methods: in 90 patients with COPD and 57 healthy controls lung function tests, physical performance tests (time up and go, gait velocity test, sit-to-stand test, isometric strength, isokinetic strength, static (functional reach test and dynamic (time up and go balance tests and the association of 25(OHD levels with lung functions, physical performance and balance were evaluated. Results: the COPD patients had significantly more deficit in physical function and balance parameters, and in dynamic balance test (p<0.005. Isokinetic knee muscle strength (flexor and extensor in COPD patients was significantly lower than in the controls (p<0.05; FEV1 (p=0.008, FVC (p=0.02, FEV1/FVC (p=0.04, TLC (p=0.01 were lower in COPD patients with vitamin D deficiency [25(OH D less than 15ng/mL] than in COPD patients without vitamin D deficiency. Hand grip test (p=0.000 and isokinetic knee muscle strength (flexor and extensor (p<0.05 were also lower in COPD patients with vitamin D deficiency. Vitamin D deficiency was more pronounced in patients with stage III COPD (p<0.05. Conclusion: patients with COPD had worst physical functioning, poor balance and less muscle strength. Severe disturbed lung and peripheral muscle functions are more pronounced in COPD patients with vitamin D deficiency.

  8. Adaptive force regulation of muscle strengthening rehabilitation device with magnetorheological fluids.

    Science.gov (United States)

    Dong, Shufang; Lu, Ke-Qian; Sun, Jian Qiao; Rudolph, Katherine

    2006-03-01

    In rehabilitation from neuromuscular trauma or injury, strengthening exercises are often prescribed by physical therapists to recover as much function as possible. Strengthening equipment used in clinical settings range from low-cost devices, such as sandbag weights or elastic bands to large and expensive isotonic and isokinetic devices. The low-cost devices are incapable of measuring strength gains and apply resistance based on the lowest level of torque that is produced by a muscle group. Resistance that varies with joint angle can be achieved with isokinetic devices in which angular velocity is held constant and variable torque is generated when the patient attempts to move faster than the device but are ineffective if a patient cannot generate torque rapidly. In this paper, we report the development of a versatile rehabilitation device that can be used to strengthen different muscle groups based on the torque generating capability of the muscle that changes with joint angle. The device is low cost, is smaller than other commercially available machines, and can be programmed to apply resistance that is unique to a particular patient and that will optimize strengthening. The core of the device, a damper with smart magnetorheological fluids, provides passive exercise force. A digital adaptive control is capable of regulating exercise force precisely following the muscle strengthening profile prescribed by a physical therapist. The device could be programmed with artificial intelligence to dynamically adjust the target force profile to optimize rehabilitation effects. The device provides both isometric and isokinetic strength training and can be developed into a small, low-cost device that may be capable of providing optimal strengthening in the home.

  9. Evaluation of Suppression of Hydroprocessed Renewable Jet (HRJ) Fuel Fires with Aqueous Film Forming Foam (AFFF)

    Science.gov (United States)

    2011-07-01

    Collecting particles from an open pan fire would preclude the consideration of isokinetic sampling usually required in Method 5, but this would...hydroprocessed renewable jet fuel in2 square inches JP-8 jet propellant 8, i.e. jet fuel kW kilowatts m2 square meters Mil-Spec Military Specification min

  10. Comparisons in fluctuation of muscle strength and function in patients with immune mediated neuropathy treated with intravenous versus subcutaneous immunoglobulin

    DEFF Research Database (Denmark)

    Christiansen, Ingelise; Markvardsen, Lars; Jakobsen, Johannes

    2018-01-01

    : In a prospective, open-label study, patients were changed from monthly IVIg to weekly SCIg. The primary endpoint was variation in isokinetic muscle strength (cIKS). Secondary endpoints were variations in Medical Research Council (MRC) score, grip strength (GS), 9-hole-peg test (9-HPT), and 40-meter-walk test (40...

  11. 40 CFR 63.1161 - Performance testing and test methods.

    Science.gov (United States)

    2010-07-01

    ..., “Determination of Hydrogen Halide and Halogen Emissions from Stationary Sources—Isokinetic Method,” to determine... shall be 60 minutes and the minimum sample volume 0.85 dry standard cubic meters (30 dry standard cubic...(mg/dscm) is concentration in milligrams per dry standard cubic meter as calculated by the procedure...

  12. A Prospective Study of Injuries and Injury Risk Factors Among Army Wheel Vehicle Mechanics

    Science.gov (United States)

    2006-08-01

    Isometric knee flexion and extension strength of the right knee was measured using the Biodex Isokinetic Measurement System. The subject was seated, with...Biomechanical effects of fatigue on 10,000 meter racing technique. Res Q Exerc Sport 1981; 52: 160-166 33. Frykman PN, Harman EA, Knapik JJ, et, al. Backpack vs

  13. Characterization of a Head-Only Aerosol Exposure System for Nonhuman Primates

    Science.gov (United States)

    2010-01-01

    Alicat Scientific). The flow used provided isokinetic sampling, assuming the presence of laminar flow at the filter inlet, so that the chamber...airflow measured at the chamber inlet using a Gilibrator flow meter (Sensidyne LP) was 29.79±0.88L/min (n= 10; CV=2.97%). With both the aerosol

  14. 75 FR 7593 - Recent Postings of Broadly Applicable Alternative Test Methods

    Science.gov (United States)

    2010-02-22

    ... quality Isokinetic Method. Pollutants for assurance; Prepare Hazardous Waste calibration standards... flow meter of Stack Gas Velocity 60.18(f)(4). in lieu of Method 2. and Volumetric Flow Rate (Type S Pitot Tube). ALT-055 Method 2A--Direct Flares subject to Use a mass flow meter Measurement of Gas 60.18...

  15. Microvascular oxygen extraction during maximal isometric contraction in patients with chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Flavia Fernandes Manfredi de Freitas

    Full Text Available Abstract Introduction: COPD presents decrease in oxidative metabolism with possible losses of cardiovascular adjustments, suggesting slow kinetics microvascular oxygen during intense exercise. Objective: To test the hypothesis that chronic obstructive pulmonary disease (COPD patients have lower muscle performance in physical exercise not dependent on central factors, but also greater muscle oxygen extraction, regardless of muscle mass. Methods: Cross-sectional study with 11 COPD patients and nine healthy subjects, male, paired for age. Spirometry and body composition by DEXA were evaluated. Muscular performance was assessed by maximal voluntary isometric contraction (MVIC in isokinetic dynamometer and muscle oxygen extraction by the NIRS technique. Student t-test and Pearson correlation were applied. A significance level of p<0.05 was adopted. Results: Patients had moderate to severe COPD (FEV1 = 44.5 ± 9.6% predicted; SpO2 = 94.6 ± 1.6%. Lean leg mass was 8.3 ± 0.9 vs. 8.9 ± 1.0 kg (p =0.033, when comparing COPD and control patients, respectively. The decreased muscle oxygen saturation corrected by muscle mass was 53.2% higher (p=0.044 in the COPD group in MVIC-1 and 149.6% higher (p=0.006 in the MVIC-2. Microvascular extraction rate of oxygen corrected by muscle mass and total work was found to be 114.5% higher (p=0.043 in the COPD group in MVIC-1 and 210.5% higher (p=0.015 in the MVIC-2. Conclusion: COPD patients have low muscle performance and high oxygen extraction per muscle mass unit and per unit of work. The high oxygen extraction suggests that quantitative and qualitative mechanisms can be determinants of muscle performance in patients with COPD.

  16. Effects of fast-velocity eccentric resistance training on early and late rate of force development

    DEFF Research Database (Denmark)

    Oliveira, Anderson S.C.; Corvino, Rogério Bulhões; Caputo, Fabrizio

    2016-01-01

    This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (phases (>100 ms) of rising torque. Twenty healthy men were......, no changes in the late phase of incremental RFD were observed in TG. No changes were found in the CG. In summary, we have demonstrated, in active individuals, that a short period of resistance training performed with eccentric fast-velocity isokinetic muscle contractions is able to enhance RFDINC and RFDREL...... assigned to two experimental groups: eccentric resistance training (TG) or control (CG). Participants on the TG trained three days a week for a total of eight weeks. Training consisted of maximal unilateral eccentric knee extensors actions performed at 180°s-1. Maximal isometric knee extensor torque (MVC...

  17. Pilot study: Effects of drinking hydrogen-rich water on muscle fatigue caused by acute exercise in elite athletes

    Directory of Open Access Journals (Sweden)

    Aoki Kosuke

    2012-07-01

    Full Text Available Abstract Background Muscle contraction during short intervals of intense exercise causes oxidative stress, which can play a role in the development of overtraining symptoms, including increased fatigue, resulting in muscle microinjury or inflammation. Recently it has been said that hydrogen can function as antioxidant, so we investigated the effect of hydrogen-rich water (HW on oxidative stress and muscle fatigue in response to acute exercise. Methods Ten male soccer players aged 20.9 ± 1.3 years old were subjected to exercise tests and blood sampling. Each subject was examined twice in a crossover double-blind manner; they were given either HW or placebo water (PW for one week intervals. Subjects were requested to use a cycle ergometer at a 75 % maximal oxygen uptake (VO2 for 30 min, followed by measurement of peak torque and muscle activity throughout 100 repetitions of maximal isokinetic knee extension. Oxidative stress markers and creatine kinase in the peripheral blood were sequentially measured. Results Although acute exercise resulted in an increase in blood lactate levels in the subjects given PW, oral intake of HW prevented an elevation of blood lactate during heavy exercise. Peak torque of PW significantly decreased during maximal isokinetic knee extension, suggesting muscle fatigue, but peak torque of HW didn’t decrease at early phase. There was no significant change in blood oxidative injury markers (d-ROMs and BAP or creatine kinease after exercise. Conclusion Adequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and improved exercise-induced decline of muscle function. Although further studies to elucidate the exact mechanisms and the benefits are needed to be confirmed in larger series of studies, these preliminary results may suggest that HW may be suitable hydration for athletes.

  18. MUSCLE-BONE INTERACTIONS ACROSS AGE IN MEN

    Directory of Open Access Journals (Sweden)

    Ian J. Palmer

    2006-03-01

    Full Text Available This study examined the relationship of muscular strength and lean tissue with age-related patterns in bone mineral density (BMD in men 20-81 years of age. Subjects were assigned to one of three age groups, Young Men (YM, (n = 25, 20-39 yrs, Middle-aged Men (MM (n = 24, 40-59 yrs, and Older Men (OM (n = 23, 60-81 yrs. Isotonic and isokinetic strength was assessed for the quadriceps and hamstrings muscle groups. DXA (Lunar DPX-IQ was used to measure spine, hip, and total body BMD and body composition. OM had significantly lower (p < 0.05 total lean body mass (LBM than MM and lower leg lean mass (LM than YM and MM. OM had significantly lower (p < 0.01 BMD than YM and MM at the femoral neck and total hip sites and a higher proportion of OM were osteopenic and osteoporotic at the total hip site. Isotonic and isokinetic strength for both muscle groups was positively related (p < 0.05 with the hip BMD sites (r = 0.38-.67. Leg LM also was positively related to hip BMD (r = 0.37-.58. Multiple Regression analyses determined that age and lean mass (LBM or leg LM were significant predictors (p < 0.05 of femoral neck, and total hip BMD, while lean mass (LBM or leg LM was a significant predictor (p < 0.05 of BMD at the spine and trochanter sites. Isotonic and isokinetic leg strength variables were significant predictors (p < 0.05 of the total body, total hip and trochanter BMD. In conclusion, leg strength, leg LM, and total LBM were significant predictors of BMD in men, independent of age. These findings emphasize the importance of maintaining lean body mass for the bone health of aging men

  19. A comprehensive strength testing protocol offers no clinical value in predicting risk of hamstring injury: a prospective cohort study of 413 professional football players.

    Science.gov (United States)

    van Dyk, Nicol; Bahr, Roald; Burnett, Angus F; Whiteley, Rod; Bakken, Arnhild; Mosler, Andrea; Farooq, Abdulaziz; Witvrouw, Erik

    2017-12-01

    Hamstring injuries remain prevalent across a number of professional sports. In football, the incidence has even increased by 4% per year at the Champions League level over the last decade. The role of muscle strength or strength ratios and their association with risk of hamstring injury remain restricted by small sample sizes and inconclusive results. The purpose of this study is to identify risk factors for hamstring injury in professional football players in an adequately powered, prospective cohort study. Using both established (isokinetic) and novel (eccentric hamstring test device) measures of muscle strength, we aimed to investigate the relationship between these strength characteristics over the entire range of motion with risk of hamstring injury. All teams (n=18) eligible to compete in the premier football league in Qatar underwent a comprehensive strength assessment during their annual periodic health evaluation at Aspetar Orthopaedic and Sports Medicine Hospital in Doha, Qatar. Variables included isokinetic strength, Nordic hamstring exercise strength and dynamic hamstring: quadriceps ratios. Of the 413 players included (68.2% of all league players), 66 suffered a hamstring injury over the two seasons. Only isokinetic quadriceps concentric at 300°/s (adjusted for bodyweight) was associated with risk of hamstring injury when considered categorically. Age, body mass and playing position were also associated with risk of hamstring injury. None of the other 23 strength variables examined were found to be associated with hamstring injury. The clinical value of isolated strength testing is limited, and its use in musculoskeletal screening to predict future hamstring injury is unfounded. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Short-term effects of upper extremity circuit resistance training on muscle strength and functional independence in patients with paraplegia.

    Science.gov (United States)

    Yildirim, Adem; Sürücü, Gülseren Dost; Karamercan, Ayşe; Gedik, Dilay Eken; Atci, Nermin; Dülgeroǧlu, Deniz; Özgirgin, Neşe

    2016-11-21

    A number of exercises to strengthen the upper extremities are recommended to increase functional independence and quality of life (QoL) in patients with paraplegia. Circuit resistance training (CRT) is a type of progressive resistive exercise performed repeatedly at fixed mechanical exercise stations. The aim of this study was to investigate the potential benefits of CRT for upper extremity muscle strength, functional independence, and QoL in patients with paraplegia. Twenty-six patients with paraplegia who were participating in a conventional rehabilitation program at a tertiary education and research hospital were enrolled in this study. The participants were randomly assigned to two groups. The exercise group participated in the CRT program, which consisted of repetitive exercises for the upper extremities performed at fixed mechanical stations 5 sessions per week for 6 weeks, in addition to conventional rehabilitation. Participants in the control group received only conventional rehabilitation over the same period. We compared the groups with respect to QoL, as well as isokinetic muscle test outcomes in the upper extremities, using the Functional Independence Measure (FIM) and Borg's scale. We observed significant increases in scores on the physical component of the FIM, Borg's scale, and QoL in both the exercise and control groups. Furthermore, the large majority of isokinetic values were significantly more improved in the exercise group compared to the control group. When post-treatment outcomes were compared between the groups, improvements in scores on the physical component of the FIM and in most isokinetic values were significantly greater in the exercise group. This study showed that CRT has positive effects on muscle strength in the upper extremities and the physical disability components of the FIM when added to conventional rehabilitation programs for paraplegic patients. However, we observed no significant improvement in QoL scores after adding CRT

  1. Outcome of hamstring ligament harvest for Anterior Cruciate Ligament reconstruction with allograft versus autograft: a clinical trial

    Directory of Open Access Journals (Sweden)

    Mehdi Moghtadaei

    2013-11-01

    Full Text Available Background: The goal of this study was to evaluate, functional capacity of the knee in flexion and internal rotation after hamstring ligament harvest for Anterior Cruciate Ligament (ACL reconstruction.Methods: Fifty patients (male and 18-45 years old with isolated ACL injury, randomly allocated in two equal groups (in one group, ACL reconstruction was performed with Tibialis Posterior allograft and in another group with quadruple hamstring ligament auto graft and before and 6 months after surgery in both groups isokinetic flexion strength and isometric internal rotation strength of knee evaluated with Biodex System 4 dynamometer and rotational torque recorder, in order. Isokinetic flexion strength evaluated in sitting and prone position; the later position was performed for deep flexion strength evaluation. Also subjective and objective assessment of all patients pre operatively and 6 months post operatively was documented with International Knee Documentation Committee (IKDC questionnaire. In this study for first time, rotational torque strength of knee was recorded with new design measure, from isometric aspect and not isokinetic.Results: Although significant improvements in IKDC scores, flexion and internal rotation capacity of the knee were observed in both groups, post operatively in respect to pre operatively; there was no significant difference between 2 groups. (P<0.05 or more than 95% confidence Interval of the differenceConclusion: This study demonstrates that ACL reconstruction surgery, improves knee performance in flexion and internal rotation, regardless of hamstring tendon harvesting. Considering potential complications of allograft (for example: transfer of harmful diseases from donor to recipient, it is logical to use hamstring auto graft ligament for ACL reconstruction surgery. Because result of this study is not longstanding follow up and limited to male sex, for more worthfull conclusion, we suggest future study in both sex

  2. Comparison of Lower Body Specific Resistance Training on the Hamstring to Quadriceps Strength Ratios in Men and Women

    Science.gov (United States)

    Dorgo, Sandor; Edupuganti, Pradeep; Smith, Darla R.; Ortiz, Melchor

    2012-01-01

    In this study, we compared hamstring (H) and quadriceps (Q) strength changes in men and women, as well as changes in conventional and functional H:Q ratios following an identical 12-week resistance training program. An isokinetic dynamometer was used to assess 14 male and 14 female participants before and after the intervention, and conventional…

  3. The Effects of Psoas Major and Lumbar Lordosis on Hip Flexion and Sprint Performance

    Science.gov (United States)

    Copaver, Karine; Hertogh, Claude; Hue, Olivier

    2012-01-01

    In this study, we analyzed the correlations between hip flexion power, sprint performance, lumbar lordosis (LL) and the cross-sectional area (CSA) of the psoas muscle (PM). Ten young adults performed two sprint tests and isokinetic tests to determine hip flexion power. Magnetic resonance imaging was used to determine LL and PM CSA. There were…

  4. Muscle strength and soccer practice as major determinants of bone mineral density in adolescents

    DEFF Research Database (Denmark)

    Seabra, André; Marques, Elisa; Brito, João

    2012-01-01

    into soccer players (SG; n=117) and control subjects (CG; n=34). Peak torque of knee extensors (PTE) and flexors (PTF) was measured during isokinetic knee joint movement (90°/s) of the dominant and non-dominant lower limbs. BMD and BMC of the whole-body, lumbar spine, dominant/non-dominant lower limb were...

  5. Evaluation of Muscle Performance in Patients with Vitamin D De ciency: Preliminary Study

    Directory of Open Access Journals (Sweden)

    Gökhan Tuna Öztürk

    2013-04-01

    Full Text Available Aim: Vitamin D de ciency is very common in general population and has potentially harmful effect on musculoskeletal system. We aimed to show the effect of vitamin D de ciency on the muscle performance by using isokinetic test. Meterial and Methods: This study includes 12 women with vitamin D de ciency for patient group and 12 healthy women for control group. We compared knee muscles performance of these two groups by using isokinetic test. Results: The mean age was 40.71 (26-57 years in patients and 41.43 (28-58 years in healthy group. There was no statistical difference between two groups at knee  exion and extension pick-torque values in 60°/s velocity and fatigue index in 180°/s velocity (respectively, p1=0.86, p2=0.12, p3=0.42. Conclusion: Vitamin D de ciency has no effect on muscle performance. Further invastigations that evaluating larger populations are needed. (Turkish Journal of Osteoporosis 2013;19: 17-9

  6. Effect of plyometric training on lower limb biomechanics in females.

    Science.gov (United States)

    Baldon, Rodrigo de Marche; Moreira Lobato, Daniel F; Yoshimatsu, Andre P; dos Santos, Ana Flávia; Francisco, Andrea L; Pereira Santiago, Paulo R; Serrão, Fábio V

    2014-01-01

    To verify the effects of plyometric training on lower limb kinematics, eccentric hip and knee torques, and functional performance. Cohort study. Research laboratory. Thirty-six females were divided into a training group (TG; n = 18) that carried out the plyometric training for 8 weeks, and a control group (CG; n = 18) that carried out no physical training. Twenty-four plyometric training sessions during approximately 8 weeks with 3 sessions per week on alternate days. Lower limb kinematics (maximum excursion of hip adduction, hip medial rotation, and knee abduction during the single leg squat), eccentric hip (abductor, adductor, medial, and lateral rotator) isokinetic peak torques and knee (flexor and extensor) isokinetic peak torques, and functional performance (triple hop test and the 6-m timed hop test). After 8 weeks, only the TG significantly reduced the values for the maximum excursion of knee abduction (P = 0.01) and hip adduction (P Plyometric training alters lower limb kinematics and increases eccentric hip torque and functional performance, suggesting the incorporation of these exercises in preventive programs for ACL injuries.

  7. Study and development of an airborne instrument for collecting aerosols and for measuring radon 222 by its active deposition

    International Nuclear Information System (INIS)

    Filippi, Dominique

    2000-01-01

    The study and development of an airborne instrument designed to collect aerosols and measure radon 222 is detailed in this thesis. Having discussed the context of radon and introduced the methods of the measurement of radon 222 by its natural active deposition, the measurement of aerosols with the Sextant Avionique/LSCE dynamic iso-kinetic probe is quantified. These estimations of the efficiency of the probe were obtained during iso-axial simulations of the flow around the probe at different sub-sonic speeds, then by the calculation of trajectories of particles at the entrance to the probe for several debit coefficients. The effect of the attack angle is discussed along with the iso-kinetic criteria of pressure necessary for the functioning of this probe. To conclude this theoretical study, the author has estimated the deposits during aerosol transport in pipes. The instrument once constructed, (dubbed A VIRAD), is then itself presented, along with the technological aspects adopted for its use. The instrument was validated during an experimental aerial study STAAARTE 99. The measures obtained during these flights are presented in the conclusions. (author) [fr

  8. Effect of once a week endurance exercise on fitness status in sedentary subjects.

    Science.gov (United States)

    Hiruntrakul, Ashira; Nanagara, Ratanavadee; Emasithi, Alongkot; Borer, Katarina T

    2010-09-01

    To study whether 3-months aerobic exercise training at moderate intensity once a week can increase fitness status in healthy sedentary young men. Randomized controlled study was performed in 37 sedentary young men, 18 to 25 years old. The exercise group (19) was assigned to work on bicycle ergometry at 60% of maximal effort, once a week for 12 weeks. The control group (18) lived a normal life style. Before and after training, aerobic fitness (VO2(max)), resting heart rate, lipid profile, and isokinetic power and strength of shoulder and knee were evaluated. In the exercise group, there was a significant increase in most fitness parameters compared with control, VO2(max) (19.7%), isokinetic power and strength of shoulder and knee (14.9%), and resting heart rate decreased (7.4%). Moderate-intensity training once a week for at least 12 weeks was sufficient to increase aerobic fitness in sedentary young men. This low frequency of exercise training may be used to encourage sedentary individuals for more compliance with physical activity.

  9. The relationship of strength and muscle balance to shoulder pain and impingement syndrome in elite quadriplegic wheelchair rugby players.

    Science.gov (United States)

    Miyahara, M; Sleivert, G G; Gerrard, D F

    1998-04-01

    Wheelchair athletes are susceptible to injuries related to overuse of the shoulder, in particular shoulder impingement syndrome. The present study examined the relationship of shoulder pain to demographic details, isokinetic strength and muscle balance in 8 elite quadriplegic rugby players. Demographic data were collected using personal interviews and each subject was clinically examined for signs of impingement syndrome by a physician. In addition each subject underwent bilateral isokinetic strength testing of the shoulder at 60 and 180 deg/s for abduction/adduction and internal/external rotation. A series of step-wise multiple discriminant analysis successfully predicted clinical symptoms from demographic, muscular strength and balance data. In particular, there was a significant deficit in adductor strength and this was related to shoulder pain and wasting of the scapular muscles. This strength deficit may be due to the high level of spinal lesions in the quadriplegic population. The level of spinal lesion may contribute to the aetiology of shoulder pathology in quadriplegia, and differentiate it from that observed in able-bodied athletes who exhibit weak abductors.

  10. Fluid-mixing studies in a hexagonal 37-pin wire-wrapped rod bundle

    International Nuclear Information System (INIS)

    Cheng, S.K.; Todreas, N.E.

    1982-02-01

    Flow-split, pressure-drop, and mixing experiments were performed on a 37-pin LMFBR rod bundle with a P/D = 1.154 and H/D = 13.4 to verify the Chiu-Hawley-Burns correlations and to supplement the existing data base. The isokinetic extraction method, pitot-static probe pressure-measurement method, and salt-tracer-injection method were used for these experiments. The experimental results of the turbulent-flow-split parameters were predicted by the correlations within 3%. However, significant discrepancy between data and correlation existed in the transition flow regime (Re/sub b/ < 10,000). Flow-split parameters for Re/sub b/ < 3000 were not attainable because of the restriction of the isokinetic extraction method. The friction factor results showed a smooth transition from the laminar-flow regime to turbulent-flow regime. They were slightly overpredicted by the correlations, especially in the laminar-flow regime. The local swirl-flow ratio, C/sub IL/, in the turbulent-flow regime was found to be about 0.28, which was within 10% of the correlation value 0.265

  11. Measurements of the Ice Water Content of Cirrus in the Tropics and Subtropics. I; Instrument Details and Validation

    Science.gov (United States)

    Weinstock, E. M.; Smith, J. B.; Sayres, D.; Pittman, J. V.; Allen, N.; Demusz, J.; Greenberg, M.; Rivero, M.; Anderson, J. G.

    2003-01-01

    We describe an instrument mounted in a pallet on the NASA WB-57 aircraft that is designed to measure the sum of gas phase and solid phase water, or total water, in cirrus clouds. Using an isokinetic inlet, a 600-watt heater mounted directly in the flow, and Lyman-alpha photofragment fluorescence technique for detection, accurate measurements of total water have been made over almost three orders of magnitude. Isokinetic flow is achieved with an actively controlled roots pump by referencing aircraft pressure, temperature, and true air speed, together with instrument flow velocity, temperature, and pressure. During CRYSTAL FACE, the instrument operated at duct temperatures sufficiently warm to completely evaporate particles up to 150 microns diameter. In flight diagnostics, intercomparison with water measured by absorption in flight, as well as intercomparisons in clear air with water vapor measured by the Harvard water vapor instrument and the JPL infrared tunable diode laser hygrometer validate the detection sensitivity of the instrument and illustrate minimal hysteresis from instrument surfaces. The simultaneous measurement of total water and water vapor in cirrus clouds yields their ice water content.

  12. 40 CFR 53.43 - Test procedures.

    Science.gov (United States)

    2010-07-01

    ... sampling zone (see § 53.42(d)). To meet the maximum blockage limit of § 53.42(a) or for convenience, part... PM10 § 53.43 Test procedures. (a) Sampling effectiveness—(1) Technical definition. The ratio (expressed... evenly spaced isokinetic samplers in the sampling zone (see § 53.42(d)) of the wind tunnel. Collect...

  13. Muscle Fatigue during Intermittent Exercise in Individuals with Mental Retardation

    Science.gov (United States)

    Zafeiridis, Andreas; Giagazoglou, Paraskevi; Dipla, Konstantina; Salonikidis, Konstantinos; Karra, Chrisanthi; Kellis, Eleftherios

    2010-01-01

    This study examined fatigue profile during intermittent exercise in 10 men with mild to moderate mental retardation (MR) and 10 men without mental retardation (C). They performed 4 x 30 s maximal knee extensions and flexions with 1-min rest on an isokinetic dynamometer. Peak torque of flexors (PTFL) and extensors (PTEX), total work (TW), and…

  14. Particle dry-deposition experiment using ambient airborne soil

    International Nuclear Information System (INIS)

    Sehmel, G.A.

    1979-01-01

    Airborne solid concentrations were measured simultaneously at sampling towers upwind and 305-m downwind of a site. When the wind speed and wind direction were identical at each site, isokinetic air samplers on the sampling towers were automatically activated. The fraction of the airborne solid plume remaining after the 305-m fetch ranged from 0.53 to 1.07

  15. Evaluating the fall risk among elderly population by choice step reaction test

    Directory of Open Access Journals (Sweden)

    Wang D

    2016-08-01

    Full Text Available Donghai Wang,1 Jian Zhang,1 Yuliang Sun,2 Wenfei Zhu,2 Shiliu Tian,1 Yu Liu1 1Key Laboratory of Exercise and Health Sciences of the Ministry of Education, Shanghai University of Sport, Shanghai, People’s Republic of China; 2School of Physical Education, Shaanxi Normal University, Xian, People’s Republic of China Abstract: Falls during daily activities are often associated with injuries and physical disabilities, thereby affecting quality of life among elder adults. Balance control, which is crucial in avoiding falls, is composed of two elements: muscle strength and central nervous system (CNS control. A number of studies have reported that reduced muscle strength raises the risk of falling. However, to date there has been only limited research focused on the relationship between fall risk and the CNS. This study aimed to investigate the relationship between CNS and risk of falling among the elderly. A total of 140 elderly people (92 females and 48 males were divided into faller and nonfaller groups based on questionnaire responses concerning falls in their daily life. Participants undertook a choice step reaction test in which they were required to respond to random visual stimuli using foot movements as fast as possible in the left or right directions. Response time was quantified as premotor time (PMT and motor time (MT. In addition, the participants’ electromyography data were recorded during the choice step reaction test. A maximal isokinetic torque test was also performed. PMT was greater in the fallers than in the nonfallers group. There was a significant difference between fall status and direction on PMT. PMT of the left limb in nonfallers was faster than the right, but in fallers there was no difference between left and right limbs. A similar phenomenon was also observed for MT. There were significant differences between fallers and nonfallers in maximum isokinetic torque at knee and ankle joints. The correct rate of PMT was

  16. Multiaxis, Lightweight, Computer-Controlled Exercise System

    Science.gov (United States)

    Haynes, Leonard; Bachrach, Benjamin; Harvey, William

    2006-01-01

    The multipurpose, multiaxial, isokinetic dynamometer (MMID) is a computer-controlled system of exercise machinery that can serve as a means for quantitatively assessing a subject s muscle coordination, range of motion, strength, and overall physical condition with respect to a wide variety of forces, motions, and exercise regimens. The MMID is easily reconfigurable and compactly stowable and, in comparison with prior computer-controlled exercise systems, it weighs less, costs less, and offers more capabilities. Whereas a typical prior isokinetic exercise machine is limited to operation in only one plane, the MMID can operate along any path. In addition, the MMID is not limited to the isokinetic (constant-speed) mode of operation. The MMID provides for control and/or measurement of position, force, and/or speed of exertion in as many as six degrees of freedom simultaneously; hence, it can accommodate more complex, more nearly natural combinations of motions and, in so doing, offers greater capabilities for physical conditioning and evaluation. The MMID (see figure) includes as many as eight active modules, each of which can be anchored to a floor, wall, ceiling, or other fixed object. A cable is payed out from a reel in each module to a bar or other suitable object that is gripped and manipulated by the subject. The reel is driven by a DC brushless motor or other suitable electric motor via a gear reduction unit. The motor can be made to function as either a driver or an electromagnetic brake, depending on the required nature of the interaction with the subject. The module includes a force and a displacement sensor for real-time monitoring of the tension in and displacement of the cable, respectively. In response to commands from a control computer, the motor can be operated to generate a required tension in the cable, to displace the cable a required distance, or to reel the cable in or out at a required speed. The computer can be programmed, either locally or via

  17. Fatigue during maximal sprint cycling: unique role of cumulative contraction cycles.

    Science.gov (United States)

    Tomas, Aleksandar; Ross, Emma Z; Martin, James C

    2010-07-01

    Maximal cycling power has been reported to decrease more rapidly when performed with increased pedaling rates. Increasing pedaling rate imposes two constraints on the neuromuscular system: 1) decreased time for muscle excitation and relaxation and 2) increased muscle shortening velocity. Using two crank lengths allows the effects of time and shortening velocity to be evaluated separately. We conducted this investigation to determine whether the time available for excitation and relaxation or the muscle shortening velocity was mainly responsible for the increased rate of fatigue previously observed with increased pedaling rates and to evaluate the influence of other possible fatiguing constraints. Seven trained cyclists performed 30-s maximal isokinetic cycling trials using two crank lengths: 120 and 220 mm. Pedaling rate was optimized for maximum power for each crank length: 135 rpm for the 120-mm cranks (1.7 m x s(-1) pedal speed) and 109 rpm for the 220-mm cranks (2.5 m x s(-1) pedal speed). Power was recorded with an SRM power meter. Crank length did not affect peak power: 999 +/- 276 W for the 120-mm crank versus 1001 +/- 289 W for the 220-mm crank. Fatigue index was greater (58.6% +/- 3.7% vs 52.4% +/- 4.8%, P < 0.01), and total work was less (20.0 +/- 1.8 vs 21.4 +/- 2.0 kJ, P < 0.01) with the higher pedaling rate-shorter crank condition. Regression analyses indicated that the power for the two conditions was most highly related to cumulative work (r2 = 0.94) and to cumulative cycles (r2 = 0.99). These results support previous findings and confirm that pedaling rate, rather than pedal speed, was the main factor influencing fatigue. Our novel result was that power decreased by a similar increment with each crank revolution for the two conditions, indicating that each maximal muscular contraction induced a similar amount of fatigue.

  18. The acute response of pericytes to muscle-damaging eccentric contraction and protein supplementation in human skeletal muscle.

    Science.gov (United States)

    De Lisio, Michael; Farup, Jean; Sukiennik, Richard A; Clevenger, Nicole; Nallabelli, Julian; Nelson, Brett; Ryan, Kelly; Rahbek, Stine K; de Paoli, Frank; Vissing, Kristian; Boppart, Marni D

    2015-10-15

    Skeletal muscle pericytes increase in quantity following eccentric exercise (ECC) and contribute to myofiber repair and adaptation in mice. The purpose of the present investigation was to examine pericyte quantity in response to muscle-damaging ECC and protein supplementation in human skeletal muscle. Male subjects were divided into protein supplement (WHY; n = 12) or isocaloric placebo (CHO; n = 12) groups and completed ECC using an isokinetic dynamometer. Supplements were consumed 3 times/day throughout the experimental time course. Biopsies were collected prior to (PRE) and 3, 24, 48, and 168 h following ECC. Reflective of the damaging protocol, integrin subunits, including α7, β1A, and β1D, increased (3.8-fold, 3.6-fold and 3.9-fold, respectively, P muscle-damaging ECC increases α7β1 integrin content in human muscle, yet pericyte quantity is largely unaltered. Future studies should focus on the capacity for ECC to influence pericyte function, specifically paracrine factor release as a mechanism toward pericyte contribution to repair and adaptation postexercise. Copyright © 2015 the American Physiological Society.

  19. Comparative analysis of quadriceps and hamstrings strength in knee osteoarthritis before and after total knee arthroplasty: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Naasson Trindade Cavanellas

    Full Text Available ABSTRACT Objective: Compare the maximal isokinetic muscle strength of knee extensor and flexor muscles between patients with knee osteoarthritis and patients submitted to total knee arthroplasty. Methods: Volunteers were divided into five groups (n = 20: Control; Ahlbäck I and II; Ahlbäck IV; six months after total knee arthroplasty; 12 months after total knee arthroplasty. An isokinetic knee strength evaluation was conducted for the quadriceps and hamstrings at 60°/s. Results: Significant differences in the peak torque of the quadriceps and hamstrings were found among the groups (p < 0.001. The Ahlbäck IV, six-month, and 12-month postoperative groups demonstrated lower values when compared to the Control and Ahlbäck I and II groups. When percentage values were compared to the Control group, mean differences ranged from 7% to 41%. Conclusion: Patients with healthy knees or early stage osteoarthritis have higher quadriceps and hamstrings strengths than those with a more advanced stage of the disease, even after knee replacement. These findings suggest that the traditional rehabilitation programs do not recover strength to levels observed in individuals without knee osteoarthritis.

  20. Influence of Anterior Cruciate Ligament Tear on Thigh Muscle Strength and Hamstring-to-Quadriceps Ratio: A Meta-Analysis

    Science.gov (United States)

    Ahn, Sung-Eun; Park, Min-Ji; Lee, Dae-Hee

    2016-01-01

    Theoretical compensation after anterior cruciate ligament (ACL) tear could cause quadriceps weakness and hamstring activation, preventing anterior tibial subluxation and affecting the expected hamstring-to-quadriceps ratio. Although quadriceps weakness often occurs after ACL tears, it remains unclear whether hamstring strength and hamstring-to-quadriceps ratio increase in ACL deficient knees. This meta-analysis compared the isokinetic muscle strength of quadriceps and hamstring muscles, and the hamstring-to-quadriceps ratio, of the injured and injured limbs of patients with ACL tears. This meta-analysis included all studies comparing isokinetic thigh muscle strengths and hamstring-to-quadriceps ratio in the injured and uninjured legs of patients with ACL tear, without or before surgery. Thirteen studies were included in the meta-analysis. Quadriceps and hamstring strengths were 22.3 N∙m (95% CI: 15.2 to 29.3 N∙m; Phamstring-to-quadriceps ratio was 4% greater in ACL deficient than in uninjured limbs (95% CI: 1.7% to 6.3%; Phamstring muscles of patients with ACL tear, with the decrease in quadriceps strength being 3-fold greater. These uneven reductions slightly increase the hamstring-to-quadriceps ratio in ACL deficient knees. PMID:26745808

  1. Supervised dance intervention based on video game choreography increases quadriceps cross sectional area and peak of torque in community dwelling older women

    Directory of Open Access Journals (Sweden)

    Elisângela Valevein Rodrigues

    2018-06-01

    Full Text Available Abstract AIMS the purpose of this study was to assess the effects of a supervised dance intervention based on video game choreography on isokinetic concentric and eccentric knee peak of torque (PT, quadriceps and hamstrings cross sectional area (CSA and functionality in community-dwelling older women. METHODS Forty-seven older women were allocated in Control Group (CG, n=25 and Intervention Group (IG, n=22. The IG performed dance based on video game choreography (Dance Central, XBOX 360®, Kinect, during 12 weeks, ~40 minutes, 3x/week, without foam (1-6week and with foam and visual disturbances (7-12 week. The pretest-training-posttest assessments included: isokinetic concentric and eccentric knee PT and CSA (Magnetic resonance imaging of quadriceps and hamstrings and functional tests. RESULTS The light-to-moderate-intensity 12-weeks training increased 8.5% the eccentric PT of quadriceps at 60°/s (p=0.04 and 1.3% quadriceps CSA (p=0.02. CONCLUSIONS These findings suggest that dance training based on video game choreography can enhance PT and induce hypertrophy in community-dwelling older women.

  2. Hamstrings strength imbalance in professional football (soccer) players in Australia.

    Science.gov (United States)

    Ardern, Clare L; Pizzari, Tania; Wollin, Martin R; Webster, Kate E

    2015-04-01

    The aim of this study was to describe the isokinetic thigh muscle strength profile of professional male football players in Australia. Concentric (60° and 240°·s(-1)) and eccentric (30° and 120°·s(-1)) hamstrings and quadriceps isokinetic strength was measured with a HUMAC NORM dynamometer. The primary variables were bilateral concentric and eccentric hamstring and quadriceps peak torque ratios, concentric hamstring-quadriceps peak torque ratios, and mixed ratios (eccentric hamstring 30°·s(-1) ÷ concentric quadriceps 240°·s(-1)). Hamstring strength imbalance was defined as deficits in any 2 of: bilateral concentric hamstring peak torque ratio imbalance. Athletes with strength imbalance had significantly reduced concentric and eccentric bilateral hamstring peak torque ratios at all angular velocities tested; and reduced eccentric quadriceps peak torque (30°·s(-1)) in their stance leg, compared with those without strength imbalance. Approximately, 1 in 4 players had preseason hamstring strength imbalance; and all strength deficits were observed in the stance leg. Concentric and eccentric hamstrings strength imbalance may impact in-season football performance and could have implications for the future risk of injury.

  3. FY06 NRL DoD High Performance Computing Modernization Program Annual Reports

    Science.gov (United States)

    2007-10-31

    nonequilibrium MD with isokinetic thermostatting. We have explored both the Green - Kubo and the mean-square displacement approaches to transport...codes. The flow solver was combined with adaptive re-meshing techniques for these transient problems with moving grids and was also integrated with the...simple one-dimensional eddy viscosity to a fully three-dimensional direct numerical simulation. Coupling between fluid and sediment phases varies from

  4. The correlation schemes in calculations of the rate constants of some radiation chemical reactions

    International Nuclear Information System (INIS)

    Zagorets, P.A.; Shostenko, A.G.; Kim, V.

    1983-01-01

    The various correlation relationships of the evaluation of the rate constants of radiation chemical reactions of addition, abstraction and isomerization were considered. It was shown that neglection of the influence of solvent can result in errors in calculations of rate constants equalling two orders in magnitude. Several examples of isokinetic relationship are given. The methods of calculation of transmission coefficient of reaction addition have been discussed. (author)

  5. Physical therapy applications of MR fluids and intelligent control

    Science.gov (United States)

    Dong, Shufang; Lu, Ke-Qian; Sun, J. Q.; Rudolph, Katherine

    2005-05-01

    Resistance exercise has been widely reported to have positive rehabilitation effects for patients with neuromuscular and orthopaedic conditions. This paper presents an optimal design of magneto-rheological fluid dampers for variable resistance exercise devices. Adaptive controls for regulating the resistive force or torque of the device as well as the joint motion are presented. The device provides both isometric and isokinetic strength training for various human joints.

  6. Strength deficits identified with concentric action of the hip extensors and eccentric action of the hamstrings predispose to hamstring injury in elite sprinters.

    Science.gov (United States)

    Sugiura, Yusaku; Saito, Tomoyuki; Sakuraba, Keishoku; Sakuma, Kazuhiko; Suzuki, Eiichi

    2008-08-01

    Prospective cohort study. In this prospective cohort study of elite sprinters, muscle strength of the hip extensors, as well as of the knee extensors and flexors, was measured to determine a possible relationship between strength deficits and subsequent hamstring injury within 12 months of testing. The method used for testing muscle strength simulated the specific muscle action during late swing and early contact phases when sprinting. There have been no prospective studies in elite sprinters that examine the concentric and eccentric isokinetic strength of the hip extensors and the quadriceps and hamstring muscles in a manner that reflects their actions in late swing or early contact phases of sprinting. Consequently, the causal relationship between hip and thigh muscle strength and hamstring injury in elite sprinters may not be fully understood. Isokinetic testing was performed on 30 male elite sprinters to assess hip extensors, quadriceps, and hamstring muscle strength. The occurrence of hamstring injury among the subjects was determined during the year following the muscle strength measurements. The strength of the hip extensors, quadriceps, and hamstring muscles, as well as the hamstrings-quadriceps and hip extensors- quadriceps ratios were compared. Hamstring injury occurred in 6 subjects during the 1-year period. Isokinetic testing at a speed of 60 degrees /s revealed weakness of the injured limb with eccentric action of the hamstring muscles and during concentric action of the hip extensors. When performing a side-to-side comparison for the injured sprinters, the hamstring injury always occurred on the weaker side. Differences in the hamstrings-quadriceps and hip extensors-quadriceps strength ratios were also evident between uninjured and injured limbs, and this was attributable to deficits in hamstring strength. Hamstring injury in elite sprinters was associated with weakness during eccentric action of the hamstrings and weakness during concentric action of

  7. Effects of Sprint Interval Training With Active Recovery vs. Endurance Training on Aerobic and Anaerobic Power, Muscular Strength, and Sprint Ability.

    Science.gov (United States)

    Sökmen, Bülent; Witchey, Ronald L; Adams, Gene M; Beam, William C

    2018-03-01

    Sökmen, B, Witchey, RL, Adams, GM, and Beam, WC. Effects of sprint interval training with active recovery vs. endurance training on aerobic and anaerobic power, muscular strength, and sprint ability. J Strength Cond Res 32(3): 624-631, 2018-This study compared sprint interval training with active recovery (SITAR) to moderate-intensity endurance training (ET) in aerobic and anaerobic power, muscular strength, and sprint time results. Forty-two recreationally active adults were randomly assigned to a SITAR or ET group. Both groups trained 3× per week for 10 weeks at 75% of V[Combining Dot Above]O2max for 30 minutes weeks 1-4, with duration increasing to 35 minutes weeks 5-7 and 40 minutes weeks 8-10. While ET ran on a 400-m track without rest for the full training session, SITAR sprinted until the 200-m mark and recovered with fast walking or light jogging the second 200 m to the finish line in 3× original sprint time. Maximal oxygen consumption (V[Combining Dot Above]O2max), anaerobic treadmill run to exhaustion at 12.5 km·h at 20% incline, isokinetic leg extension and flexion strength at 60 and 300°·s, and 50 m sprint time were determined before and after training. Results showed a significant improvement (p ≤ 0.05) in absolute and relative V[Combining Dot Above]O2max, anaerobic treadmill run, and sprint time in both groups. Only SITAR showed significant improvements in isokinetic leg extension and flexion at 300°·s and decreases in body mass (p ≤ 0.05). SITAR also showed significantly greater improvement (p ≤ 0.05) over ET in anaerobic treadmill run and 50 m sprint time. These data suggest that SITAR is a time-efficient strategy to induce rapid adaptations in V[Combining Dot Above]O2max comparable to ET with added improvements in anaerobic power, isokinetic strength, and sprint time not observed with ET.

  8. Comparison of hamstring/quadriceps ratio between isoinertial and isokinetic measurements

    NARCIS (Netherlands)

    Da Silva, Bruna G C; Bottaro, Martim; Weber, Fernanda S.; Radaelli, Regis; Gaya, Anelise R.; Cardoso, Marcelo S.; Brown, Lee E.; Carregaro, Rodrigo; Pinto, Ronei S.

    2013-01-01

    OBJECTIVE: To determine the applicability and predictive accuracy of an isoinertial resistance machine for the assessment of hamstring/quadriceps conventional (concentric) ratio (CR). METHOD: Thirty-two resistance trained young men (23.53 ± 3.2 yrs) were tested using dedicated instruments to obtain

  9. Posture and isokinetic shoulder strength in female water polo players

    African Journals Online (AJOL)

    Kathryn van Boom

    pathological injuries, such as rotator cuff tendinitis, shoulder instability and shoulder ... and specific postural characteristics, which will be useful in future studies. ... concentric and eccentric IR and ER shoulder muscle strength in 15 club-level ...

  10. Associations between muscle structure and contractile performance in seniors.

    Science.gov (United States)

    Randhawa, Avleen; Wakeling, James M

    2013-07-01

    Changes in muscle structure due to aging occur in a process known as sarcopenia. These changes can alter muscle mechanics during contraction that may limit mobility in seniors. The purpose of this study was to investigate the effect of sarcopenia on muscle fascicle length, pennation and belly thickness in a contracting muscle during isokinetic movements. Fascicles within a pennate muscle shorten at a slower velocity than that of the muscle belly, in a process called belly gearing. Belly gearing may be affected by atrophy and so was also tested in these seniors. The gastrocnemii were tested using ultrasound from 10 young adults (20-40 years) and 9 seniors (70-85 years). The muscle structure was imaged during standing and maximal plantarflexion at four constant velocities on a dynamometer and torque, position and time were recorded during contractions. The muscle belly thickness and pennation in seniors were significantly lower than young adults during standing. Belly thickness, changes in pennation, the belly gearing, ankle torque and power output were all significantly lower in seniors during plantarflexion contractions of the medial gastrocnemius (MG) and lateral gastrocnemius (LG). The higher pennation observed in young adults is commonly associated with increased fascicle rotations during contraction causing an increased belly gearing. The decreased fascicle rotations in seniors resulted in reduced belly gearing but the size of this effect did not match the loss in strength or power from the muscles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Innovative Technology Development for Comprehensive Air Quality Characterization from Open Burning

    Science.gov (United States)

    2012-04-01

    data acquisition computer with a Roots meter . Following sampling, the glass cartridge (sorbent) was removed from the Flyer, wrapped in clean aluminum...Determination Of Hydrogen Halide And Halogen Emissions From Stationary Sources Non- Isokinetic Method. U.S. EPA Method 3A, Carbon Monoxide. U.S...flowrate and concentration. HCl gas will be metered via a mass flow controller and will target concentrations seen in the field during sampling (ca. 20

  12. A Laboratory Investigation of Aerosol and Extinction Characteristics for SALTY DOG, NWC 29 and NWC 78 Pyrotechnics

    Science.gov (United States)

    1980-10-01

    The artificial fogs are produced by 1’SALTY DOC,14 and phosphorus pentoxide smokeS~in Calspan’s 590 cubic meter chamber at controlled relative...the chamber experiments, an isokinetic sampling inlet was employed for minimizing aerosol losses during sampling. Instrumentation used to monitor...with a 1 cfm critical orifice and vacuum pump. Additionally, a flow meter , placed behind the filter, was monitored to assure that filter loading did

  13. A Comparison of the US Air Force Fitness Test and Sister Services’ Combat-Oriented Fitness Tests

    Science.gov (United States)

    2009-03-01

    their status quo. These changes included changing their road runs into 400- to 800- meter (m) interval training, reducing their test run distance from 5...sleep were recorded throughout the operation. Measures of fitness were the isokinetic strength of the arms and legs, isometric handgrip strength...JIT = Just-In-Time (training) km = kilometer MANUF = Maneuver-Under-Fire (drill within the CFT) MFTC = Master Fitness Trainer Course m = meter

  14. Relationships among hamstring muscle optimal length and hamstring flexibility and strength

    OpenAIRE

    Xianglin Wan; Feng Qu; William E. Garrett; Hui Liu; Bing Yu

    2017-01-01

    Background: Hamstring muscle strain injury (hamstring injury) due to excessive muscle strain is one of the most common injuries in sports. The relationships among hamstring muscle optimal lengths and hamstring flexibility and strength were unknown, which limited our understanding of risk factors for hamstring injury. This study was aimed at examining the relationships among hamstring muscle optimal length and flexibility and strength. Methods: Hamstring flexibility and isokinetic strength ...

  15. Sprint Acceleration Mechanics: The Major Role of Hamstrings in Horizontal Force Production

    Science.gov (United States)

    Morin, Jean-Benoît; Gimenez, Philippe; Edouard, Pascal; Arnal, Pierrick; Jiménez-Reyes, Pedro; Samozino, Pierre; Brughelli, Matt; Mendiguchia, Jurdan

    2015-01-01

    Recent literature supports the importance of horizontal ground reaction force (GRF) production for sprint acceleration performance. Modeling and clinical studies have shown that the hip extensors are very likely contributors to sprint acceleration performance. We experimentally tested the role of the hip extensors in horizontal GRF production during short, maximal, treadmill sprint accelerations. Torque capabilities of the knee and hip extensors and flexors were assessed using an isokinetic dynamometer in 14 males familiar with sprint running. Then, during 6-s sprints on an instrumented motorized treadmill, horizontal and vertical GRF were synchronized with electromyographic (EMG) activity of the vastus lateralis, rectus femoris, biceps femoris, and gluteus maximus averaged over the first half of support, entire support, entire swing and end-of-swing phases. No significant correlations were found between isokinetic or EMG variables and horizontal GRF. Multiple linear regression analysis showed a significant relationship (P = 0.024) between horizontal GRF and the combination of biceps femoris EMG activity during the end of the swing and the knee flexors eccentric peak torque. In conclusion, subjects who produced the greatest amount of horizontal force were both able to highly activate their hamstring muscles just before ground contact and present high eccentric hamstring peak torque capability. PMID:26733889

  16. Sprint acceleration mechanics: the major role of hamstrings in horizontal force production

    Directory of Open Access Journals (Sweden)

    Jean-Benoit eMORIN

    2015-12-01

    Full Text Available Recent literature supports the importance of horizontal ground reaction force (GRF production for sprint acceleration performance. Modeling and clinical studies have shown that the hip extensors are very likely contributors to sprint acceleration performance. We experimentally tested the role of the hip extensors in horizontal GRF production during short, maximal, treadmill sprint accelerations. Torque capabilities of the knee and hip extensors and flexors were assessed using an isokinetic dynamometer in 14 males familiar with sprint running. Then, during 6-s sprints on an instrumented motorized treadmill, horizontal and vertical GRF were synchronized with electromyographic (EMG activity of the vastus lateralis, rectus femoris, biceps femoris and gluteus maximus averaged over the first half of support, entire support, entire swing and end-of-swing phases. No significant correlations were found between isokinetic or EMG variables and horizontal GRF. Multiple linear regression analysis showed a significant relationship (P = 0.024 between horizontal GRF and the combination of biceps femoris EMG activity during the end of the swing and the knee flexors eccentric peak torque. In conclusion, subjects who produced the greatest amount of horizontal force were both able to highly activate their hamstring muscles just before ground contact and present high eccentric hamstring peak torque capability.

  17. Efficiency of developing 15–17-year weightlifters’ training process for a one-year macrocycle with the use of various speed and strength training methods

    Directory of Open Access Journals (Sweden)

    Oleksandr Piven

    2017-10-01

    Full Text Available Purpose: developed and experimentally tested the construction of the training process of weightlifters of 15–17 years during a one-year macrocycle with the use of various speed and strength training methods. Material & Methods: to the experiment were attracted 30 young weightlifters at the age of 15–17 years, they all had II and III sports categories. Results: it was found that the athletes of the experimental group who used the unconventional training method, using different training regimes – isokinetic, plyometric, half-dynamic, impact method with speed-strength training, which included jumping with various devices in depth and jumping out, after the experiment, they improved their strengths in the amount of the duathlon by 16,5 kg, and also set their own records in contrast to the control group that trained by the traditional method and improved the power results by 7,2 kg. Conclusion: it is established that the use of non-traditional methods for the development of speed-strength qualities of weightlifters, namely, different training regimes – isokinetic, plyometric, half-dynamic, shock method, contributes to the more efficient development of speed-strength qualities, and, consequently, leads to an increase in sports performance in weightlifting.

  18. Assessing the therapeutic effect of 625-nm light-emitting diodes

    Science.gov (United States)

    Mao, Zongzhen; Xu, Guodong; Yang, Yi

    2014-09-01

    To evaluate the effects of red Light-Emitting Diodes on elbow extensor and flexor strength and the recovery of exercise induced fatigue, the torque values from the isokinetic dynamometer as well as biochemistry parameters were used as outcome measures. A randomized double-blind placebo-controlled crossover trial was performed with twenty male young tennis athletes. Active LED therapy (LEDT, with wavelength 625nm, 10 minutes total irradiation time, irradiated area amount to 30cm2, and 900J of total energy irradiated) or an identical placebo was delivered under double-blinded conditions to the left elbow just before exercise. The isokinetic muscle strength was measured immediately after irradiation. The blood lactate levels were sampled pre-exercise and post-exercise. The peak torque values of elbow extensor strength were significantly different between two groups. As in elbow flexor strength, the difference of peak torque was not significant. The blood lactate concentration of LEDT group post-exercise was significantly lower than those of placebo group. The results indicate that 625nm LED therapy is effective in preventing muscle fatigue as it can significantly reduce peak torque value of elbow extensors and blood lactate concentration. It has no effect on the strength of left elbow flexor or backhand performance in tennis.

  19. A molecular dynamics simulation code ISIS

    International Nuclear Information System (INIS)

    Kambayashi, Shaw

    1992-06-01

    Computer simulation based on the molecular dynamics (MD) method has become an important tool complementary to experiments and theoretical calculations in a wide range of scientific fields such as physics, chemistry, biology, and so on. In the MD method, the Newtonian equations-of-motion of classical particles are integrated numerically to reproduce a phase-space trajectory of the system. In the 1980's, several new techniques have been developed for simulation at constant-temperature and/or constant-pressure in convenient to compare result of computer simulation with experimental results. We first summarize the MD method for both microcanonical and canonical simulations. Then, we present and overview of a newly developed ISIS (Isokinetic Simulation of Soft-spheres) code and its performance on various computers including vector processors. The ISIS code has a capability to make a MD simulation under constant-temperature condition by using the isokinetic constraint method. The equations-of-motion is integrated by a very accurate fifth-order finite differential algorithm. The bookkeeping method is also utilized to reduce the computational time. Furthermore, the ISIS code is well adopted for vector processing: Speedup ratio ranged from 16 to 24 times is obtained on a VP2600/10 vector processor. (author)

  20. Computerized plutonium laboratory-stack monitoring system

    International Nuclear Information System (INIS)

    Stafford, R.G.; DeVore, R.K.

    1977-01-01

    The Los Alamos Scientific Laboratory has recently designed and constructed a Plutonium Research and Development Facility to meet design criteria imposed by the United States Energy Research and Development Administration. A primary objective of the design criteria is to assure environmental protection and to reliably monitor plutonium effluent via the ventilation exhaust systems. A state-of-the-art facility exhaust air monitoring system is described which establishes near ideal conditions for evaluating plutonium activity in the stack effluent. Total and static pressure sensing manifolds are incorporated to measure average velocity and integrated total discharge air volume. These data are logged at a computer which receives instrument data through a multiplex scanning system. A multipoint isokinetic sampling assembly with associated instrumentation is described. Continuous air monitors have been designed to sample from the isokinetic sampling assembly and transmit both instantaneous and integrated stack effluent concentration data to the computer and various cathode ray tube displays. The continuous air monitors also serve as room air monitors in the plutonium facility with the primary objective of timely evacuation of personnel if an above tolerance airborne plutonium concentration is detected. Several continuous air monitors are incorporated in the ventilation system to assist in identification of release problem areas

  1. Sampling of contaminants from product gases of biomass gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Staahlberg, P.; Lappi, M.; Kurkela, E.; Simell, P.; Oesch, P.; Nieminen, M. [VTT Energy, Espoo (Finland). New Energy Technologies

    1998-12-01

    Reliable sampling and analysis of products from biomass gasification are essential for the successful process development and economical operation of commercial gasifiers. One of the most important and most difficult analytical tasks is to characterise the emissions from the gasifiers. This report presents a review of the sampling and analytical systems employed and developed when doing research on coal and biomass gasification. In addition to the sampling systems published in the literature, experiences obtained in various biomass gasification R and D projects of VTT in 1985-1995 are described. The present sampling methods used for different gas contaminants at VTT are also briefly presented. This report focuses mainly on the measurement of tars, nitrogen compounds and sulphur gases. Isokinetic and non-isokinetic sampling train systems are described and, in addition, special sampling apparatus based on liquid-quenched probe and gas dilution is briefly outlined. Sampling of tars with impinger systems and sampling of heavy tars with filter techniques are described in detail. Separate sampling of particulates is briefly discussed. From inorganic compounds the sampling systems used for H{sub 2}S and other sulphur gases, NH{sub 3} and HCN and HCl are presented. Proper storage of the samples is also included in the report. (orig.) 90 refs.

  2. Recovery Kinetics of Knee Flexor and Extensor Strength after a Football Match

    Science.gov (United States)

    Draganidis, Dimitrios; Chatzinikolaou, Athanasios; Avloniti, Alexandra; Barbero-Álvarez, José C.; Mohr, Magni; Malliou, Paraskevi; Gourgoulis, Vassilios; Deli, Chariklia K.; Douroudos, Ioannis I.; Margonis, Konstantinos; Gioftsidou, Asimenia; Fouris, Andreas D.; Jamurtas, Athanasios Z.; Koutedakis, Yiannis; Fatouros, Ioannis G.

    2015-01-01

    We examined the temporal changes of isokinetic strength performance of knee flexor (KF) and extensor (KE) strength after a football match. Players were randomly assigned to a control (N = 14, participated only in measurements and practices) or an experimental group (N = 20, participated also in a football match). Participants trained daily during the two days after the match. Match and training overload was monitored with GPS devices. Venous blood was sampled and muscle damage was assessed pre-match, post-match and at 12h, 36h and 60h post-match. Isometric strength as well as eccentric and concentric peak torque of knee flexors and extensors in both limbs (dominant and non-dominant) were measured on an isokinetic dynamometer at baseline and at 12h, 36h and 60h after the match. Functional (KFecc/KEcon) and conventional (KFcon/KEcon) ratios were then calculated. Only eccentric peak torque of knee flexors declined at 60h after the match in the control group. In the experimental group: a) isometric strength of knee extensors and knee flexors declined (Pfootball-specific conditioning. Our data suggest that recovery kinetics of knee flexor and extensor strength after a football match demonstrate strength, limb and velocity specificity and may depend on match physical overload and players' physical conditioning level. PMID:26043222

  3. Effects of a whole body vibration training program on strength, power, and functional tests in the physically active elderly

    Directory of Open Access Journals (Sweden)

    Renata Gonçalves da Silva

    2009-04-01

    Full Text Available The aim of this study was to investigate the effect of a whole body vibration training program on knee extensor isokinetic peak torque, average power, and functional tests in the physically active elderly. Forty-seven subjects, who participated in a training program for the elderly, were recruited. The subjects were divided into two groups: whole body vibration group (WBV (n=24, 70.7±5.8 years, 62.7±12.3 kg and 155.9±8.0 cm and control group (n=23. 70.0±5.7 years, 65.3±10.7 kg and 157.9±6.6 cm. The WBS group underwent whole body vibration exercise and their regular training program for 13 weeks, 2 times per week, whereas the control group performed the regular training program only. Whole body vibration training was not effective in increasing isokinetic peak torque, average power, or performance in the functional tests. On the other hand, the regular training program was effective in increasing elbow flexor strength endurance, distance covered in the 6-min walk test, and speed in the timed up and go test. The results suggest that vibration training is not effective in modifying functionality or muscle strength and power in the physically active elderly.

  4. Characterisation of the suspended particulate matter in a stratified estuarine environment employing complementary techniques

    Science.gov (United States)

    Thomas, Luis P.; Marino, Beatriz M.; Szupiany, Ricardo N.; Gallo, Marcos N.

    2017-09-01

    The ability to predict the sediment and nutrient circulation within estuarine waters is of significant economic and ecological importance. In these complex systems, flocculation is a dynamically active process that is directly affected by the prevalent environmental conditions. Consequently, the floc properties continuously change, which greatly complicates the characterisation of the suspended particle matter (SPM). In the present study, three different techniques are combined in a stratified estuary under quiet weather conditions and with a low river discharge to search for a solution to this problem. The challenge is to obtain the concentration, size and flux of suspended elements through selected cross-sections using the method based on the simultaneous backscatter records of 1200 and 600 kHz ADCPs, isokinetic sampling data and LISST-25X measurements. The two-ADCP method is highly effective for determining the SPM size distributions in a non-intrusive way. The isokinetic sampling and the LISST-25X diffractometer offer point measurements at specific depths, which are especially useful for calibrating the ADCP backscatter intensity as a function of the SPM concentration and size, and providing complementary information on the sites where acoustic records are not available. Limitations and potentials of the techniques applied are discussed.

  5. Operation PLUMBBOB. Summary Report, Test Group 57, Nevada Test Site. Extracted Version

    Science.gov (United States)

    1982-06-04

    02 to 1 micron A common suction pump was used for all air samplers. Its intake rate of approximately 17 liters per minute, or one cubic meter per...the wind, are isokinetic in their sampling for normal wind-speed ranges. The volume sampled is directly proportional to wind speed, since impact...3.2.2 Chronic Exposures As soon as isoconcentration lines were established from alpha- meter survey readings, the chronic-exposure pens were set out

  6. Valve for a dust meter. Ventil fuer eine Staubkonzentrationsmessanordnung

    Energy Technology Data Exchange (ETDEWEB)

    1985-08-01

    When sampling a representative gas or dust flow from a flue, the characteristics of the sample must remain unchanged. As sampling is carried out using a pump, a valve is provided through which the isokinetic component current is led across a dust deposition length and, via a bypass, back into the flue. The valve has a distributor casing with a distributor cylinder and with three connections that do not change the volume flow.

  7. Sea Salt Aerosol, Atmospheric Radon and Meteorological Observations in the Western South Atlantic Ocean (February 1981).

    Science.gov (United States)

    1983-09-28

    approximately isokinetic sampling conditions. The blower motor for the hi-vol was separated from the filter holder unit by a one- meter length of flexible...bridge bulkhead about 15 m above sea level and within 3 meters of the ARCAS inlet. The flow rate through the 20 cm x 25 cm glass fiber filters was...materials, atmospheric pressure, soil moisture and vegetative cover (Larson and Bressan, 1980). Radon concentrations measured a few meters above

  8. Acute effects of dynamic exercises on the relationship between the motor unit firing rate and the recruitment threshold.

    Science.gov (United States)

    Ye, Xin; Beck, Travis W; DeFreitas, Jason M; Wages, Nathan P

    2015-04-01

    The aim of this study was to compare the acute effects of concentric versus eccentric exercise on motor control strategies. Fifteen men performed six sets of 10 repetitions of maximal concentric exercises or eccentric isokinetic exercises with their dominant elbow flexors on separate experimental visits. Before and after the exercise, maximal strength testing and submaximal trapezoid isometric contractions (40% of the maximal force) were performed. Both exercise conditions caused significant strength loss in the elbow flexors, but the loss was greater following the eccentric exercise (t=2.401, P=.031). The surface electromyographic signals obtained from the submaximal trapezoid isometric contractions were decomposed into individual motor unit action potential trains. For each submaximal trapezoid isometric contraction, the relationship between the average motor unit firing rate and the recruitment threshold was examined using linear regression analysis. In contrast to the concentric exercise, which did not cause significant changes in the mean linear slope coefficient and y-intercept of the linear regression line, the eccentric exercise resulted in a lower mean linear slope and an increased mean y-intercept, thereby indicating that increasing the firing rates of low-threshold motor units may be more important than recruiting high-threshold motor units to compensate for eccentric exercise-induced strength loss. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Biomechanical Assessment of Motor Abilities in Male Handball Players During the Annual Training Macrocycle

    Directory of Open Access Journals (Sweden)

    Sacewicz Tomasz

    2016-12-01

    Full Text Available Introduction. The aim of the study was to determine the torque of the knee extensors and flexors of the lead lower limb, the torque of the shoulder extensors and flexors of the dominant upper limb, and the torque generated by the muscles of the kinematic chain going from the trail lower limb to the hand of the dominant limb in male handball players during the annual training macrocycle. Changes in jump height and throwing velocity were also investigated. Material and methods. The study involved 13 handball players from a Polish second-league team. The measurements were performed four times: at the beginning of the preparation period, at the beginning of the season, at the end of the first part of the season, and at the end of the second part of the season. Torque was measured in isokinetic and isometric conditions. Jumping ability was tested using a piezoelectric platform, and throwing velocity was measured with a speed radar gun. Results. The study found statistically significant differences between the relative torque values of the knee extensors (p < 0.002 and flexors (p < 0.003 of the lead leg measured in isokinetic conditions between the first three measurements and the final one. Isokinetic measurement of the torque of the muscles of the kinematic chain going from the trail leg to the hand of the dominant arm decreased in a statistically significant way at the end of the season. As for the results of the measurement of the torque of the shoulder extensors and flexors in static conditions, no statistically significant differences were observed between the four measurements. However, statistically significant differences were noted in jumping ability and throwing velocity in the annual training macrocycle. Conclusions. The results of the study indicate that there is a need to perform regular assessments of players’ strength and jumping ability during the competition period. There is a need to modify the training methods used during the

  10. Effect of short-term upper-body resistance training on muscular strength, bone metabolic markers, and BMD in premenopausal women

    Directory of Open Access Journals (Sweden)

    Liang MT

    2012-11-01

    Full Text Available Michael TC Liang,1 Lorena Quezada,1 WY Jamie Lau,1 Bulent Sokmen,2 Thomas W Spalding11Department of Kinesiology and Health Promotion, California State Polytechnic University, Pomona, CA, USA; 2Department of Kinesiology, Sonoma State University, Rohnert Park, CA, USAAbstract: To examine the effect of a 10-week upper-body resistance training program on bone turnover markers and site-specific bone mineral density (BMD in the wrist and distal half of the ulna and radius in untrained and healthy young premenopausal women.Methods: Twenty-two subjects (aged 22.1 ± 1.8 years were randomly assigned to a resistance training (n = 12 or no training control (n = 10 group. The following outcome variables were measured before and after 10 weeks of resistance training: (1 bone formation biomarker osteocalcin, and bone resorption biomarker tartrate-resistant acid phosphatase isoform 5b; (2 BMD in the wrist and distal half of the ulna and radius; (3 isokinetic strength of the elbow and knee extensors and flexors; (4 dynamic strength of the arm extensors and flexors; and (5 maximum number of push-ups.Results: The 10-week upper body resistance training intervention resulted in improved strength performance in push-ups (resistance training versus control: P < 0.05, chest presses (P < 0.05, and pulldowns (P < 0.05. However, there was no improvement in the BMD of the wrist (P > 0.05, BMD of the distal half of the ulna and radius (P > 0.05, and metabolic biomarkers osteocalcin (P > 0.05 and tartrate-resistant acid phosphatase isoform 5b (P > 0.05, except for the osteocalcin/tartrate-resistant acid phosphatase isoform 5b ratio. Also, no improvement in the resistance training group was observed for isokinetic strength of the knee and elbow flexion/extension.Conclusion: Upper-body muscular strength performance, but not bone metabolic markers and BMD of the wrist, can be improved with a 10-week upper body resistance training program of the nonweight-bearing limbs in

  11. Muscular strength measurements indicate bone mineral density loss in postmenopausal women

    Directory of Open Access Journals (Sweden)

    Zhou Z

    2013-10-01

    Full Text Available Zhixiong Zhou,1,2 Lu Zheng,3 Dengyun Wei,4 Ming Ye,3 Xun Li2 1School of Physical Education and Coaching Science, Capital University of Physical Education and Sports, Beijing, People’s Republic of China; 2Graduate School, Beijing Sport University, Beijing, People’s Republic of China; 3School of Kinesiology and Health Education, Capital University of Physical Education and Sports, Beijing, People’s Republic of China; 4Department of Physical Education, Anhui Normal University, Anhui, People’s Republic of China Background: The literature is inconsistent and inconclusive on the relationship between bone mineral density (BMD and muscular strength in postmenopausal women. Objective: To evaluate the relationship between isokinetically and isometrically determined muscle strength and BMD in postmenopausal women of different age groups. Methods: Healthy postmenopausal women (n = 293; mean age, 54.22 ± 3.85 years were enrolled in this study. They were grouped by age according to World Health Organization life expectancy: 45–50 years, 51–53 years, 54–56 years, 57–59 years, and 60–64 years. Total BMD, L2–4 BMD, and femoral neck BMD were measured by dual-energy X-ray bone densitometry; isokinetic and isometric muscle strength of the right hip and trunk muscles were measured during contractile exercise. Stepwise regression analysis was used to examine the relationships between BMD and strength measures, controlling for subject age and years since menopause. Results: Results of stepwise regression showed that hip extensor and flexor strength at 120°/second and back extend strength at 30°/second accounted for 26% total BMD variance among menopausal subjects, 19% L2–4 BMD variance, and 15% femoral neck BMD variance; in postmenopausal women of different age groups, hip extensor and flexor strength at 120°/second and back extend strength at 30°/second accounted for 25%–35% total BMD variance. Conclusion: Different optimal strength

  12. Analysis of Aerosols and Fallout from High-Explosive Dust Clouds. Volume 2

    Science.gov (United States)

    1977-03-01

    mately 100 CFM enabled the system to sample isokinetically for pirticles larger than 80 j/m diameter with appropriate correction factors for...2-5 pm dia- meter . The yellow, green, and red varieties of F. P. are unique and can- not be confused with natural materials which commonly fluoresce...their magnitude is in- dicated in the pass by "remarks" section. The cloud width in meters was determined from the simple equation: Width = 0.447 x TAS

  13. Turbulent Coolant Dispersion in the Wake of a Turbine Vane Trailing Edge

    Science.gov (United States)

    2015-01-01

    streak injection point. A bulk flow of 0.3 liters per minute supplies the three hot streaks, which are individually metered to ensure isokinetic ...the model sizes are limited to tens of centimeters, with flow velocities of a few meters per second. The Prandtl and Schmidt numbers of the working...channel illustrated in Figures 2.7, 2.8 and 2.9. Metered flow is delivered to the apparatus through a 38 mm diameter hose. Two successive diffusing

  14. Fugitive Dust Emissions: Development of a Real-time Monitor

    Science.gov (United States)

    2011-10-01

    mean wind speed indicate that, for a typical mean wind speed of 4.4 m/s, particles larger than about 100 μm are likely to deposit within 10 meters ...from the point of emission. Particles that are 30 to 100 μm in diameter typically deposit within a few hundred meters from the injection point...Willeke, 1990). In general, it is accepted that isoaxial and isokinetic conditions result in representative sampling of aerosol particles from most

  15. Muscle torque of healthy individuals and individuals with spastic hemiparesis after passive static streching.

    Science.gov (United States)

    Tatsukawa DE Freitas, Sérgio Takeshi; DE Carvalho Abreu, Elizângela Márcia; Dos Reis, Mariane Cecilia; DE Souza Cunha, Bruna; Souza Moreira Prianti, Tamires; Pupio Silva Lima, Fernanda; Oliveira Lima, Mário

    2016-01-01

    Spasticity is one of the main causes of contracture, muscle weakness and subsequent functional incapacity. The passive static stretching can be included as having the purpose of increasing musculoskeletal flexibility, however, it also can influence the muscle torque. The objective is to verify the immediate effect of passive static stretching in the muscle strength of healthy and those who present spastic hemiparesis. There were assessed 20 subjects, 10 spastic hemiparetic (EG) and 10 healthy individuals (CG), including both sexes, aged between 22 and 78 years. The torque of extensor muscles of the knee was analyzed using isokinetic dynamometer. Results have shown that EG has less muscle torque compared to CG ( p torque after stretching ( p torque of CG after performing the program that was prescribed. Immediately after the passive stretch, a significant torque decrease can be seen in hypertonic muscle; it is believed that this reduction may be associated with the physiological overlap between actin and myosin filaments and so preventing the muscle to develop a maximum contraction.

  16. Different Muscle Action Training Protocols on Quadriceps-Hamstrings Neuromuscular Adaptations.

    Science.gov (United States)

    Ruas, Cassio V; Brown, Lee E; Lima, Camila D; Gregory Haff, G; Pinto, Ronei S

    2018-05-01

    The aim of this study was to compare three specific concentric and eccentric muscle action training protocols on quadriceps-hamstrings neuromuscular adaptations. Forty male volunteers performed 6 weeks of training (two sessions/week) of their dominant and non-dominant legs on an isokinetic dynamometer. They were randomly assigned to one of four groups; concentric quadriceps and concentric hamstrings (CON/CON, n=10), eccentric quadriceps and eccentric hamstrings (ECC/ECC, n=10), concentric quadriceps and eccentric hamstrings (CON/ECC, n=10), or no training (CTRL, n=10). Intensity of training was increased every week by decreasing the angular velocity for concentric and increasing it for eccentric groups in 30°/s increments. Volume of training was increased by adding one set every week. Dominant leg quadriceps and hamstrings muscle thickness, muscle quality, muscle activation, muscle coactivation, and electromechanical delay were tested before and after training. Results revealed that all training groups similarly increased MT of quadriceps and hamstrings compared to control (p0.05). These findings suggest that different short-term muscle action isokinetic training protocols elicit similar muscle size increases in hamstrings and quadriceps, but not for other neuromuscular variables. Nevertheless, effect sizes indicate that CON/ECC and ECC/ECC may elicit the greatest magnitude of change in muscle hypertrophy. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Impaired hip muscle strength in patients with femoroacetabular impingement syndrome.

    Science.gov (United States)

    Kierkegaard, Signe; Mechlenburg, Inger; Lund, Bent; Søballe, Kjeld; Dalgas, Ulrik

    2017-12-01

    Patients with femoroacetabular impingement (FAI) experience hip pain as well as decreased function and lowered quality of life. The aim was to compare maximal isometric and isokinetic muscle strength (MVC) during hip flexion and extension and rate of force development (RFD) during extension between patients with FAI and a matched reference group. Secondary, the aim was to compare patient hips and subgroups defined by gender and age as well as to investigate associations between hip muscle strength and self-reported outcomes. Design Cross-sectional, comparative study Methods Sixty patients (36±9 years, 63% females) and 30 age and gender matched reference persons underwent MVC tests in an isokinetic dynamometer. During hip flexion and extension, patients' affected hip showed a strength deficit of 15-21% (phip of the patients was significantly weaker than their contralateral hip. RFD was significantly decreased for both patient hips compared to the reference group (phip muscle strength. Patients with FAI demonstrate decreased hip flexion and extension strength when compared to (1) reference persons and (2) their contralateral hip. There seems to be a gender specific affection which should be investigated further and addressed when planning training protocols. Furthermore, self-reported measures were associated with isometric muscle strength, which underlines the clinical importance of the reduced muscle strength. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  18. Water adsorption isotherms and thermodynamic properties of cassava bagasse

    International Nuclear Information System (INIS)

    Polachini, Tiago Carregari; Betiol, Lilian Fachin Leonardo; Lopes-Filho, José Francisco; Telis-Romero, Javier

    2016-01-01

    Highlights: • Adsorption isotherms and composition of cassava bagasse were determined. • GAB equation was the best-fitted model to sorption data of type II isotherm. • Isosteric heat of sorption was calculated in a range of equilibrium moisture content. • Differential enthalpy and entropy confirmed the isokinetic compensation theory. • Water adsorption by cassava bagasse is considered an enthalpy driven process. - Abstract: Losses of food industry are generally wet products that must be dried to posterior use and storage. In order to optimize drying processes, the study of isotherms and thermodynamic properties become essential to understand the water sorption mechanisms of cassava bagasse. For this, cassava bagasse was chemically analyzed and had its adsorption isotherms determined in the range of 293.15–353.15 K through the static gravimetric method. The models of GAB, Halsey, Henderson, Oswin and Peleg were fitted, and best adjustments were found for GAB model with R"2 > 0.998 and no pattern distribution of residual plots. Isosteric heat of adsorption and thermodynamic parameters could be determined as a function of moisture content. Compensation theory was confirmed, with linear relationship between enthalpy and entropy and higher values of isokinetic temperature (T_B = 395.62 K) than harmonic temperature. Water adsorption was considered driven by enthalpy, clarifying the mechanisms of water vapor sorption in cassava bagasse.

  19. Effect of a resistance exercise program for sarcopenic elderly women: quasi-experimental study

    Directory of Open Access Journals (Sweden)

    Joana Ude Viana

    2018-04-01

    Full Text Available Abstract Introduction: Resistance training is quoted as one of the best pathways to manage sarcopenia and progressive resistance training is supposed to improve muscle mass, strength and performance in older adults. Objective: The aim was to examine the impact of a progressive resistance exercise program (PREP on muscle and function performance in sarcopenic community-dwelling elder women. Methods: Quasi-experimental study (pre - post intervention. Participated 18 sarcopenic community-dwelling elder women (65 years or older. PREP based on 75% of the participant’s maximum load (12/wk, 3 times/wk. Main outcome measures: muscle strength of knee extensors (isokinetic dynamometry, muscle mass (dual-x ray absorptiometry - DXA, functional performance (Short Physical Performance Battery - SPPB. Paired t-test was used to evaluate differences pre and post intervention. Results: Improvements on power (p = 0.01 and peak torque (p = 0.01 were observed when measured by the isokinetic dynamometer at low speed (60º/s. Improvements on DXA (pre PREP: 5.49 kg/m2 vs. post PREP: 6.01 kg/m2; p = 0.03 and SPPB scores (pre PREP: 9.06 vs. post PREP: 10.28; p = 0.01 were also observed. Conclusion: The PREP was able to improve muscle and functional performance in sarcopenic community-dwelling elder women. This program should be considered in clinical practice.

  20. Nonparetic Knee Extensor Strength Is the Determinant of Exercise Capacity of Community-Dwelling Stroke Survivors

    Directory of Open Access Journals (Sweden)

    Wei-Te Wang

    2014-01-01

    Full Text Available Objective. To investigate the relationship among walking speed, exercise capacity, and leg strength in community dwelling stroke subjects and to evaluate which one was the leading determinant factor of them. Design. This is a descriptive, cross-sectional study. Thirty-five chronic stroke patients who were able to walk independently in their community were enrolled. Walking speed was evaluated by using the 12-meter walking test. A maximal exercise test was used to determine the stroke subjects’ exercise capacity. Knee extensor strength, measured as isokinetic torque, was assessed by isokinetic dynamometer. Results. The main walking speed of our subjects was 0.52 m/s. Peak oxygen uptake (VO2 peak was 1.21±0.43 L/min. Knee extensor strength, no matter whether paretic or nonparetic side, was significantly correlated to 12-meter walking speed and exercise capacity. Linear regression also showed the strength of the affected knee extensor was the determinant of walking speed and that of the nonparetic knee extensor was the determinant of exercise capacity in community dwelling stroke subjects. Conclusions. Walking speed and peak oxygen uptake were markedly decreased after stroke. Knee extensor strength of nonparetic leg was the most important determinant of exercise capacity of the community-dwelling stroke subjects. Knee extensor strengthening should be emphasized to help stroke patient to achieve optimal community living.

  1. Nonparetic knee extensor strength is the determinant of exercise capacity of community-dwelling stroke survivors.

    Science.gov (United States)

    Wang, Wei-Te; Huang, Ling-Tzu; Chou, Ya-Hui; Wei, Ta-Sen; Lin, Chung-Che

    2014-01-01

    To investigate the relationship among walking speed, exercise capacity, and leg strength in community dwelling stroke subjects and to evaluate which one was the leading determinant factor of them. This is a descriptive, cross-sectional study. Thirty-five chronic stroke patients who were able to walk independently in their community were enrolled. Walking speed was evaluated by using the 12-meter walking test. A maximal exercise test was used to determine the stroke subjects' exercise capacity. Knee extensor strength, measured as isokinetic torque, was assessed by isokinetic dynamometer. The main walking speed of our subjects was 0.52 m/s. Peak oxygen uptake (VO₂ peak) was 1.21 ± 0.43 L/min. Knee extensor strength, no matter whether paretic or nonparetic side, was significantly correlated to 12-meter walking speed and exercise capacity. Linear regression also showed the strength of the affected knee extensor was the determinant of walking speed and that of the nonparetic knee extensor was the determinant of exercise capacity in community dwelling stroke subjects. Walking speed and peak oxygen uptake were markedly decreased after stroke. Knee extensor strength of nonparetic leg was the most important determinant of exercise capacity of the community-dwelling stroke subjects. Knee extensor strengthening should be emphasized to help stroke patient to achieve optimal community living.

  2. IS ENHANCED-ECCENTRIC RESISTANCE TRAINING SUPERIOR TO TRADITIONAL TRAINING FOR INCREASING ELBOW FLEXOR STRENGTH?

    Directory of Open Access Journals (Sweden)

    Thomas W. Kaminski

    2003-06-01

    Full Text Available Protocols for strengthening muscle are important for fitness, rehabilitation, and the prevention of myotendinous injuries. In trained individuals, the optimal method of increasing strength remains unclear. The purpose of this study was to compare the effects of a traditional method of strengthening with a method that allowed for enhanced-eccentric training, on changes in elbow flexor strength in trained subjects. Thirty-nine (8 male, 31 female trained subjects with normal elbow function participated in this study. Subjects were rank-ordered according to isometric force production and randomly assigned to one of three training groups: control (CONT, traditional concentric/eccentric (TRAD, and concentric/enhanced-eccentric (NEG. The training groups completed 24 training sessions. An evaluator blinded to training group performed all testing. Mixed model ANOVA techniques were used to determine if differences existed in concentric one repetition maximum strength, and isometric force production among groups. Changes in peak and average isokinetic force production were also compared. Type 1 error was maintained at 5%. While both groups improved concentric one repetition maximum (NEG = 15.5%, TRAD = 13.8% neither training group statistically differed from changes demonstrated by the CONT group. Nor did either training group show significant improvements in isometric or isokinetic force production over the CONT group. These results do not support the superiority of enhanced-eccentric training for increasing force production in trained subjects.

  3. Knee function and knee muscle strength in middle-aged patients with degenerative meniscal tears eligible for arthroscopic partial meniscectomy

    DEFF Research Database (Denmark)

    Stensrud, Silje; Risberg, May Arna; Roos, Ewa M.

    2014-01-01

    BACKGROUND: Functional limitations exist postmeniscectomy, but preoperative data are scarce. PURPOSE: To examine knee function, knee muscle strength and performance in middle-aged patients with degenerative meniscal tears, eligible for arthroscopic partial meniscectomy. STUDY DESIGN: Cross......-sectional study. METHODS: Eighty-two participants with MRI verified degenerative meniscal tear (35% women, mean age 49 years) answered the Knee injury and Osteoarthritis Outcome Score (KOOS) and were tested for isokinetic knee muscle strength and lower extremity performance (one-leg hop for distance, 6 m timed...

  4. Injury Prevention and Performance Optimization in Soldiers of the Army 101st Airborne/Air Assault Division

    Science.gov (United States)

    2011-04-01

    understanding and familiarity. A rest period of at least 60 de- gree/seconds was given prior to each strength test. Reciprocal concentric isokinetic ...of approxi- mately 84 cm, and the height of a window or a wall and the depth of a ditch can be close to a meter or more. Moreover, the maximum VGRF...drills, and agility drills. Shuttle runs and sprints used a fun- nel design, with the volume (total distance) progressing from high (274 meters (m)) to

  5. Sand and Dust Testing of Wheeled and Tracked Vehicles and Stationary Equipment

    Science.gov (United States)

    2009-11-18

    Vacuum pump Flow meter Measurement of dust mass ±2 percent ±4 percent ±0.0005 g Weight of air cleaner element ±0.5 percent (Total estimated error...samplers should be set to a flow rate that is isokinetic ) on the front of the vehicle, in the center of the grill or windshield, or the center of...3) Record the test bed vehicle odometer and hour meter reading. (4) Document the condition of the vehicle interior, exterior, and all

  6. Energetic Residues and Crater Geometries from the Firing of 120-mm High-Explosive Mortar Projectiles into Eagle River Flats, June 2007

    Science.gov (United States)

    2008-07-01

    samples. ERDC/CRREL TR-08-10 15 c. US DH-48 isokinetic sampler. Figure 7 (cont’d). The second activity was the collection of soil at the...3 0.28 Mc1/3 0.3 Mc1/3 Ra Apparent radius of the crater in meters Mc Mass of the explosive charge in kilograms Da Apparent depth of the crater in... meters The apparent depth and radius of a crater will increase with the depth of explosive charge below the surface down to a maximum depth called

  7. Demonstration/Validation of the TC-60 Controlled Detonation Chamber, Porton Down, UK: Final Demonstration Test Report

    Science.gov (United States)

    2007-06-01

    8217 Av.-l R Ave Ave Fl O e---_ 7_ Run Time Total Volume Metered Delta P Delta H Gas Temp. Temp. Page I od gsnanne re/Date) Team ’ure/DýC- C-86 Isokinetic ...process equipment. When the ball valves are open, gaseous oxygen is controlled by a regulator and automatically metered into the detonation chamber by a...compounds emitted to the atmosphere "• The dioxin/furan toxic equivalent concentration was in the low femtogram (fg) per normal cubic meter concentration

  8. ROLE OF HAMSTRING MUSCLES IN KNEE JOINT STABILITY PROVIDING AND INJURY PREVENTION

    OpenAIRE

    Pontaga, Inese

    2016-01-01

    The aim of our investigation was to determine the ratio of maximal torque values and the torques in the certain positions of range of movements (ROM) between hamstring (H) and quadriceps femoris (Q) muscles at medium and high velocity of movement in concentric (CC) and eccentric (ECC) action of hamstring muscles. The knee muscles of 15 amateur female short and middle distance runners were tested by the dynamometer system in the isokinetic movements with the angular velocity of 90º/s and 240º...

  9. Influence of the Flo-Dynamics Movement System© intervention on measures of performance in older persons

    Directory of Open Access Journals (Sweden)

    Carlson LA

    2013-07-01

    Full Text Available Lara A Carlson,1 Alexander J Koch,2 Michael Lawrence11University of New England, Biddeford, ME, 2Lenoir-Rhyne University, Hickory, NC, USABackground: Fall-related injuries associated with aging are a serious clinical and economic problem. The Flo-Dynamics Movement System© (FDMS, which consists of eight movements with a water-filled device, may be a useful low-impact exercise suited for older persons. This study investigated the effects of the FDMS regimen with the Wun-Jo™ trainer on measures of strength, flexibility, and balance in older individuals.Methods: In a quasi-experimental study, 15 healthy subjects aged 61–79 years participated in an FDMS exercise program with the Wun-Jo trainer, consisting of three weekly 30-minute sessions. The following measures were assessed pretraining and after 8 weeks of training: knee flexor and extensor isokinetic strength; grip strength; the Short Physical Performance Battery; functional reach; and low back and hamstring flexibility. Data were analyzed using repeated measures analysis of variance, with statistical significance set at the P ≤ 0.05 confidence level.Results: Sit and reach test scores significantly increased (+21% from baseline to week 8 (P < 0.001. Forward-left functional reach testing significantly increased (P = 0.012, while forward-right functional reach testing did not change (P = 0.474. Both left-lateral (P = 0.012 and right-lateral (P = 0.036 functional reach scores improved. Grip strength increased in both the left (+11.9% and right (+14.5% hands (P < 0.001 for each. Isokinetic knee extension at 60° per second increased for the left (+15.6% and right (+17.6% significantly (P = 0.001 for each. Isokinetic knee flexion at 60° per second significantly increased for both the left (+43.2%, P = 0.010 and right (+41.7%, P < 0.001. Time to complete the ten-repetition chair stand decreased significantly (-31%, P = 0.004. The 8-feet walk time also significantly decreased (-21.6%, P < 0

  10. Strength and hypertrophy responses to constant and decreasing rest intervals in trained men using creatine supplementation.

    Science.gov (United States)

    Souza-Junior, Tácito P; Willardson, Jeffrey M; Bloomer, Richard; Leite, Richard D; Fleck, Steven J; Oliveira, Paulo R; Simão, Roberto

    2011-10-27

    The purpose of the current study was to compare strength and hypertrophy responses to resistance training programs that instituted constant rest intervals (CI) and decreasing rest intervals (DI) between sets over the course of eight weeks by trained men who supplemented with creatine monohydrate (CR). Twenty-two recreationally trained men were randomly assigned to a CI group (n = 11; 22.3 ± 1 years; 77.7 ± 5.4 kg; 180 ± 2.2 cm) or a DI group (n = 11; 22 ± 2.5 years; 75.8 ± 4.9 kg; 178.8 ± 3.4 cm). Subjects in both groups supplemented with CR; the only difference between groups was the rest interval instituted between sets; the CI group used 2 minutes rest intervals between sets and exercises for the entire 8-weeks of training, while the DI group started with a 2 minute rest interval the first two weeks; after which the rest interval between sets was decreased 15 seconds per week (i.e. 2 minutes decreasing to 30 seconds between sets). Pre- and post-intervention maximal strength for the free weight back squat and bench press exercises and isokinetic peak torque were assessed for the knee extensors and flexors. Additionally, muscle cross-sectional area (CSA) of the right thigh and upper arm was measured using magnetic resonance imaging. Both groups demonstrated significant increases in back squat and bench press maximal strength, knee extensor and flexor isokinetic peak torque, and upper arm and right thigh CSA from pre- to post-training (p ≤ 0.0001); however, there were no significant differences between groups for any of these variables. The total volume for the bench press and back squat were significantly greater for CI group versus the DI group. We report that the combination of CR supplementation and resistance training can increase muscular strength, isokinetic peak torque, and muscle CSA, irrespective of the rest interval length between sets. Because the volume of training was greater for the CI group versus the DI group, yet strength gains were

  11. Strength and hypertrophy responses to constant and decreasing rest intervals in trained men using creatine supplementation

    Directory of Open Access Journals (Sweden)

    Fleck Steven J

    2011-10-01

    Full Text Available Abstract Background The purpose of the current study was to compare strength and hypertrophy responses to resistance training programs that instituted constant rest intervals (CI and decreasing rest intervals (DI between sets over the course of eight weeks by trained men who supplemented with creatine monohydrate (CR. Methods Twenty-two recreationally trained men were randomly assigned to a CI group (n = 11; 22.3 ± 1 years; 77.7 ± 5.4 kg; 180 ± 2.2 cm or a DI group (n = 11; 22 ± 2.5 years; 75.8 ± 4.9 kg; 178.8 ± 3.4 cm. Subjects in both groups supplemented with CR; the only difference between groups was the rest interval instituted between sets; the CI group used 2 minutes rest intervals between sets and exercises for the entire 8-weeks of training, while the DI group started with a 2 minute rest interval the first two weeks; after which the rest interval between sets was decreased 15 seconds per week (i.e. 2 minutes decreasing to 30 seconds between sets. Pre- and post-intervention maximal strength for the free weight back squat and bench press exercises and isokinetic peak torque were assessed for the knee extensors and flexors. Additionally, muscle cross-sectional area (CSA of the right thigh and upper arm was measured using magnetic resonance imaging. Results Both groups demonstrated significant increases in back squat and bench press maximal strength, knee extensor and flexor isokinetic peak torque, and upper arm and right thigh CSA from pre- to post-training (p ≤ 0.0001; however, there were no significant differences between groups for any of these variables. The total volume for the bench press and back squat were significantly greater for CI group versus the DI group. Conclusions We report that the combination of CR supplementation and resistance training can increase muscular strength, isokinetic peak torque, and muscle CSA, irrespective of the rest interval length between sets. Because the volume of training was greater for the

  12. ACUTE EFFECTS OF DIFFERENT STATIC STRETCHING PROTOCOLS ON PEAK TORQUE, CONVENTIONAL AND FUNCTIONAL HAMSTRINGS-TO-QUADRICEPS RATIOS IN ACTIVE WOMEN

    Directory of Open Access Journals (Sweden)

    Ghada M. ALQaslah

    2016-10-01

    Full Text Available Background: This study might have been directed to some degree because of clashing results in the past studies regarding the impacts for different SS protocols on muscle strength and possibility for injury. The objective of the study was to investigate the acute effects of different static stretching (SS durations (20, 30, and 60s on isokinetic concentric quadriceps (Q and hamstrings (H peak torque (PT, eccentric H PT and conventional and functional H:Q ratios under different stretching conditions and angular velocities (60°and180°/s in active women. Methods: Isokinetic tests were performed on 108 active women. A HUMAC system was used to measure unilateral concentric Q and H PT, and eccentric H PT at 60 and 180º/s at baseline and after a bout of H-only, Q-only, and combined H and Q muscles SS. The data were statistically treated using five separate three-way (time x conditions x velocity ANOVA. Results: There were no significant differences among groups at baseline (P > 0.05. Significant reductions of all outcome measures have been shown to occur after 30 and 60s of SS (P 0.05. Conclusion: Short-lasting stretching can be done before exercises that require strength. However, since 30s or 60s stretching protocols adversely affect the muscle strength, performance and lower H:Q ratios they are not recommended prior to activities demanding the production of high forces.

  13. Multimodal assessment of sensorimotor shoulder function in patients with untreated anterior shoulder instability and asymptomatic handball players.

    Science.gov (United States)

    Mornieux, Guillaume; Hirschmüller, Anja; Gollhofer, Albert; Südkamp, Norbert P; Maier, Dirk

    2018-04-01

    Functional evaluation of sensorimotor function of the shoulder joint is important for guidance of sports-specific training, prevention and rehabilitation of shoulder instability. Such assessment should be multimodal and comprise all qualities of sensorimotor shoulder function. This study evaluates feasibility of such multimodal assessment of glenohumeral sensorimotor function in patients with shoulder instability and handball players. Nine patients with untreated anterior instability of their dominant shoulder and 15 asymptomatic recreational handball players performed proprioceptive joint position sense and dynamic stabilization evaluations on an isokinetic device, as well as a functional throwing performance task. Outcome measures were analysed individually and equally weighted in a Shoulder-Specific Sensorimotor Index (S-SMI). Finally, isokinetic strength evaluations were conducted. We observed comparable sensorimotor functions of unstable dominant shoulders compared to healthy, contralateral shoulders (e.g. P=0.59 for S-SMI). Handball players demonstrated superior sensorimotor function of their dominant shoulders exhibiting a significantly higher throwing performance and S-SMI (P0.22). The present study proves feasibility of multimodal assessment of shoulder sensorimotor function in overhead athletes and patients with symptomatic anterior shoulder instability. Untreated shoulder instability led to a loss of dominance-related sensorimotor superiority indicating functional internal rotation deficiency. Dominant shoulders of handball players showed a superior overall sensorimotor function but weakness of dominant internal rotation constituting a risk factor for occurrence of posterior superior impingement syndrome. The S-SMI could serve as a diagnostic tool for guidance of sports-specific training, prevention and rehabilitation of shoulder instability.

  14. Do Psychosocial Factors Predict Muscle Strength, Pain, or Physical Performance in Patients With Knee Osteoarthritis?

    Science.gov (United States)

    Baert, Isabel A C; Meeus, Mira; Mahmoudian, Armaghan; Luyten, Frank P; Nijs, Jo; Verschueren, Sabine M P

    2017-09-01

    The aim of this study was to examine the relationship of psychosocial factors, namely, pain catastrophizing, kinesiophobia, and maladaptive coping strategies, with muscle strength, pain, and physical performance in patients with knee osteoarthritis (OA)-related symptoms. A total of 109 women (64 with knee OA-related symptoms) with a mean age of 65.4 years (49-81 years) were recruited for this study. Psychosocial factors were quantified by the Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, and Pain Coping Inventory. Clinical features were assessed using isometric and isokinetic knee muscle strength measurements, visual analog scale, Western Ontario and McMaster Universities Osteoarthritis Index, and functional tests. Associations were examined using correlation and regression analysis. In knee OA patients, pain catastrophizing, kinesiophobia, and coping strategy explained a significant proportion of the variability in isometric knee extension and flexion strength (6.3%-9.2%), accounting for more overall variability than some demographic and medical status variables combined. Psychosocial factors were not significant independent predictors of isokinetic strength, knee pain, or physical performance. In understanding clinical features related to knee OA, such as muscle weakness, pain catastrophizing, kinesiophobia, and coping strategy might offer something additional beyond what might be explained by traditional factors, underscoring the importance of a biopsychosocial approach in knee OA management. Further research on individual patient characteristics that mediate the effects of psychosocial factors is, however, required in order to create opportunities for more targeted, personalized treatment for knee OA.

  15. Does external pneumatic compression treatment between bouts of overreaching resistance training sessions exert differential effects on molecular signaling and performance-related variables compared to passive recovery? An exploratory study.

    Science.gov (United States)

    Haun, Cody T; Roberts, Michael D; Romero, Matthew A; Osburn, Shelby C; Mobley, Christopher B; Anderson, Richard G; Goodlett, Michael D; Pascoe, David D; Martin, Jeffrey S

    2017-01-01

    We sought to compare the effects of external pneumatic compression (EPC) and sham when used concurrently with resistance training on performance-related outcomes and molecular measures related to recovery. Twenty (N = 20) resistance-trained male participants (aged 21.6±2.4 years) were randomized to balanced sham or EPC intervention groups. The protocol consisted of 3 consecutive days of heavy, voluminous back squat exercise followed by EPC/sham treatment (Days2-4) and 3 consecutive days of recovery (Days5-7) with EPC/sham only on Days5-6. On Day1 (PRE), and Days3-7, venipuncture, flexibility and pressure-to-pain threshold (PPT) measures were performed. Vastsus lateralis muscle tissue was biopsied at PRE, 1-h post-EPC/sham treatment on Day2 (POST1) and 24-h post-EPC/sham treatment on Day7 (POST2). Isokinetic peak torque was assessed at PRE and POST2. Peak isokinetic strength did not change from PRE to POST2 in either group. The PPT was significantly lower on Days3-6 with sham, indicating greater muscle soreness, though this was largely abolished in the EPC group. A significant decrease in flexibility with sham was observed on Day3 (+16.2±4.6% knee joint angle; P0.01). Vastus lateralis poly-ubiquitinated proteins significantly increased at the POST2 time point relative to PRE with sham (+66.6±24.6%; Pmuscle oxidative stress and proteolysis markers during recovery from heavy resistance exercise.

  16. Acute effects of short and long duration dynamic stretching protocols on muscle strength

    Directory of Open Access Journals (Sweden)

    Christiano Francisco dos Santos

    Full Text Available Objective Compare the acute effects of dynamic stretching protocols on the isokinetic performance of the quadriceps and hamstring muscles at two velocities in adult males.Methodology Included the participation of 14 males (21 ± 2.6 years; 178 ± 0.4 cm; 73.2 ± 20.9 kg were assessed using an isokinetic dynamometer before and after following a short or long-duration dynamic stretching protocol or a control protocol. The results were assessed by a two-way ANOVA and a Scheffé’s post hoc test at a 5% significance level.Results No difference was found in the variables assessed at 180°/s after LDDS. At 60°/s, LDDS reduced the power of the knee flexors. The control protocol reduced the power of the knee flexors and increased the power of the extensors. At 60°/s, the work of the knee flexors exhibited a reduction after LDDS. The control protocol resulted in a reduction in the work of the flexors. The peak torque angle exhibited a reduction in the extensors and flexors after LDDS and SDDS.Conclusion Dynamic stretching did not cause any change in the peak torque, which points to its possible use in activities involving velocity and muscle strength. The executing dynamic stretching before physical activities such as running and high-intensity sports might be beneficial by promoting increases in heart rate and in body temperature.

  17. Effects of photobiomodulation therapy (pulsed LASER 904 nm) on muscle oxygenation and performance in exercise-induced skeletal muscle fatigue in young women: a pilot study

    Science.gov (United States)

    Oliveira, Murilo X.; Toma, Renata L.; Jones, Brett J. L.; Cyprien, Thomas P.; Tier, Matthew R.; Wallace, Cameron A.; Renno, Ana C. M.; Sabapathy, Surendran; Laakso, E.-Liisa

    2017-02-01

    Photobiomodulation therapy (PBMt) has been used to increase muscle performance and improve recovery when applied before exercise. We aimed to evaluate the effects of PBMt using LASER on muscle oxygenation and performance. The study was a randomized, participant and assessor-blinded, within-subject crossover trial with placebo control to test the viability of the methods. Five physically active young women were randomly assigned to either placebo, or active PBMt (12 diode cluster probe; 904 nm; 60 mW; 250 Hz; 43.2 J per site, 129.6 J total) in contact over rectus femoris (RF) muscle of the dominant limb immediately before an isokinetic fatigue protocol. A one-week wash-out period preceded cross-over. Electromyography and isokinetic performance measures were evaluated. Absolute concentrations of deoxygenated haemoglobin and myoglobin (deoxy[Hb + Mb]) of the RF, an index of local microvascular fractional O2 extraction, was monitored continuously by near-infrared spectroscopy (NIRS). Total haemoglobin concentration as an indicator of microvascular haematocrit was calculated as the sum of the deoxy[Hb + Mb] and oxy[Hb + Mb] signals. PBMt pre-conditioning reduced time to peak torque when compared to placebo (P0.05). PBMt before exercise improves indicators of muscle performance, potentially by increasing local matching of bulk and microvascular O2 delivery relative to skeletal muscle O2 utilisation. Further work is required to understand the effect of PBMt on haemodynamic and metabolic characteristics of muscle.

  18. A randomized controlled trial on the effects of combined aerobic-resistance exercise on muscle strength and fatigue, glycemic control and health-related quality of life of type 2 diabetes patients.

    Science.gov (United States)

    Tomas-Carus, Pablo; Ortega-Alonso, Alfredo; Pietilainen, Kirsi H; Santos, Vitoria; Goncalves, Helena; Ramos, Jorge; Raimundo, Armando

    2016-05-01

    The aim of this paper was to evaluate the effects of a 12-weeks combined aerobic-resistance exercise therapy on fatigue and isokinetic muscle strength, glycemic control and health-related quality of life (HRQoL) in moderately affected type 2 diabetes (T2DM) patients. A randomized controlled trial design was employed. Forty-three T2DM patients were assigned to an exercise group (N.=22), performing 3 weekly sessions of 60 minutes of combined aerobic-resistance exercise for 12-weeks; or a no exercise control group (N.=21). Both groups were evaluated at a baseline and after 12-weeks of exercise therapy for: 1) muscle strength and fatigue by isokinetic dynamometry; 2) plasma glycated hemoglobin A1C (HbA1C); and 3) HRQoL utilizing the SF-36 questionnaire. The exercise therapy led to improvements in muscle fatigue in knee extensors (-55%) and increased muscle strength in knee flexors and extensors (+15 to +30%), while HbA1C decreased (-18%). In addition, the exercising patients showed sizeable improvements in HRQoL: physical function (+53%), vitality (+21%) and mental health (+40%). Twelve-weeks of combined aerobic-resistance exercise was highly effective to improve muscle strength and fatigue, glycemic control and several aspects of HRQoL in T2DM patients. These data encourage the use of aerobic and resistance exercise in the good clinical care of T2DM.

  19. Influence of Anterior Cruciate Ligament Tear on Thigh Muscle Strength and Hamstring-to-Quadriceps Ratio: A Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Hyun-Jung Kim

    Full Text Available Theoretical compensation after anterior cruciate ligament (ACL tear could cause quadriceps weakness and hamstring activation, preventing anterior tibial subluxation and affecting the expected hamstring-to-quadriceps ratio. Although quadriceps weakness often occurs after ACL tears, it remains unclear whether hamstring strength and hamstring-to-quadriceps ratio increase in ACL deficient knees. This meta-analysis compared the isokinetic muscle strength of quadriceps and hamstring muscles, and the hamstring-to-quadriceps ratio, of the injured and injured limbs of patients with ACL tears. This meta-analysis included all studies comparing isokinetic thigh muscle strengths and hamstring-to-quadriceps ratio in the injured and uninjured legs of patients with ACL tear, without or before surgery. Thirteen studies were included in the meta-analysis. Quadriceps and hamstring strengths were 22.3 N∙m (95% CI: 15.2 to 29.3 N∙m; P<0.001 and 7.4 N∙m (95% CI: 4.3 to 10.5 N∙m; P<0.001 lower, respectively, on the injured than on the uninjured side. The mean hamstring-to-quadriceps ratio was 4% greater in ACL deficient than in uninjured limbs (95% CI: 1.7% to 6.3%; P<0.001. Conclusively, Decreases were observed in both the quadriceps and hamstring muscles of patients with ACL tear, with the decrease in quadriceps strength being 3-fold greater. These uneven reductions slightly increase the hamstring-to-quadriceps ratio in ACL deficient knees.

  20. EFFECT OF DIFFERENT LEVELS OF LOCALIZED MUSCLE FATIGUE ON KNEE POSITION SENSE

    Directory of Open Access Journals (Sweden)

    William S. Gear

    2011-12-01

    Full Text Available There is little information available regarding how proprioceptive abilities decline as the amount of exertion increases during exercise. The purpose of this study was to determine the role of different levels of fatigue on knee joint position sense. A repeated measures design was used to examine changes in active joint reposition sense (AJRS prior to and following three levels of fatigue. Eighteen participants performed knee extension and flexion isokinetic exercise until torque output was 90%, 70%, or 50% of the peak hamstring torque for three consecutive repetitions. Active joint reposition sense at 15, 30, or 45 degrees was tested following the isokinetic exercise session. Following testing of the first independent measure, participants were given a 20 minute rest period. Testing procedures were repeated for two more exercise sessions following the other levels of fatigue. Testing of each AJRS test angle was conducted on three separate days with 48 hours between test days. Significant main effect for fatigue was indicated (p = 0.001. Pairwise comparisons indicated a significant difference between the pre-test and following 90% of peak hamstring torque (p = 0.02 and between the pre-test and following 50% of peak hamstring torque (p = 0.02. Fatigue has long been theorized to be a contributing factor in decreased proprioceptive acuity, and therefore a contributing factor to joint injury. The findings of the present study indicate that fatigue may have an effect on proprioception following mild and maximum fatigue.

  1. Musculoskeletal profile of middle-aged Ving Tsun Chinese martial art practitioners: A cross-sectional study.

    Science.gov (United States)

    Fong, Shirley S M; Chan, Jessie S M; Bae, Young-Hyeon; Yam, Timothy T T; Chung, Louisa M Y; Ma, Ada W W; Kuisma, Raija

    2017-01-01

    This cross-sectional exploratory study aimed to quantify and compare the axial and appendicular bone mineral density (BMD), muscle mass, and muscle strength of middle-aged practitioners of Ving Tsun (VT; a hard-style Chinese martial art) with those of nonpractitioners.Eighteen VT practitioners (mean age ± standard deviation = 51.8 ± 17.7 years; 12 men and six women) and 36 active controls (mean age ± standard deviation = 58.7 ± 11.0 years; 18 men and 18 women) participated in the study. All participants underwent a 1-day battery of musculoskeletal examinations. The BMD of the total radius, total hip, femoral neck, and lumbar spine was measured using dual-energy X-ray absorptiometry, as was the lean mass of the arm, leg, and trunk. Muscle strength of the upper and lower limbs was assessed using a Jamar dynamometer and an isokinetic dynamometer at 60°/second, respectively.VT-trained participants had a 11.5% higher total radius BMD (P = 0.023), a 17.8% higher leg lean mass (P = 0.014), a 56.4% higher isokinetic body weight-adjusted peak torque of the knee extensors (P  0.05).Middle-aged VT practitioners displayed a higher total radius BMD and leg lean mass and better knee extensor and flexor muscular performances than their healthy active counterparts. Healthcare professionals may consider using this alternative method of training to improve the musculoskeletal health of middle-aged adults.

  2. Shoulder pain among high-level volleyball players and preseason features.

    Science.gov (United States)

    Forthomme, Benedicte; Wieczorek, Valerie; Frisch, Anne; Crielaard, Jean-Michel; Croisier, Jean-Louis

    2013-10-01

    The main goal of this prospective study was to identify the most significant intrinsic risk factors for shoulder pain by measuring strength developed by shoulder rotators and by carrying out various morphostatic assessments. Sixty-six players (mean ± SD age = 24 ± 5 yr) were recruited from nine volleyball teams from the first and second divisions (34 men and 32 women) to participate in the study. Before the start of the volleyball season, all the participants completed a preseason questionnaire and underwent both a bilateral isokinetic evaluation of the shoulders and morphostatic measurements. During the subsequent 6 months of the competition period, the players reported through a weekly questionnaire any shoulder pain experienced. During the ongoing season, 23% (15 of 66 players) of the volleyball players experienced dominant shoulder pain. Interestingly, participants who reported a history of dominant shoulder pain were found to have nine times higher risk of suffering further pain in their dominant shoulder. The eccentric maximal strength developed by the internal and external rotators was found to represent a protective factor in the volleyball players (respective odds ratios = 0.946, P = 0.01 and 0.94, P = 0.05). No risk factors were found among the shoulder morphostatic measurements. In our study, the evaluation of shoulder rotator muscle strength through isokinetic assessment, especially eccentric mode, appeared to be the most contributing parameter to identify risk factors for shoulder pain. This evaluation should allow to better identify players at risk.

  3. The influence of variable range of motion training on neuromuscular performance and control of external loads.

    Science.gov (United States)

    Clark, Ross A; Humphries, Brendan; Hohmann, Erik; Bryant, Adam L

    2011-03-01

    Resistance training programs that emphasize high force production in different regions of the range of motion (ROM) may provide performance benefits. This study examined whether variable ROM (VROM) training, which consists of partial ROM training with countermovements performed in a different phase of the ROM for each set, results in improved functional performance. Twenty-two athletes (age 22.7 ± 2.4 years, height 1.81 ± 0.07 m, and body mass 94.6 ± 14.5 kg) with extensive resistance training backgrounds performed either a VROM or full ROM control (CON) 5-week, concentric work-matched training program. The participants were assigned to a group based on stratified randomization incorporating their strength levels and performance gains in preceding training microcycles. Testing consisted of assessing the force-ROM relationship during isokinetic and isometric bench press and ballistic bench throws, with normalized electromyography amplitude assessed during the isometric tests. Repeated-measure analyses of variance revealed that the VROM intervention significantly (p force (+15.7%), in addition to isokinetic peak force in the terminal ROM (13.5% increase). No significant differences were observed in the CON group or between groups for any other outcome measures. Analysis of the force-ROM relationship revealed that that the VROM intervention enhanced performance at shorter muscle lengths. These findings suggest that VROM training improves terminal and midrange performance gains, resulting in the athlete possessing an improved ability to control external loading and produce dynamic force.

  4. Influence of Skeletal Muscle Carnosine Content on Fatigue during Repeated Resistance Exercise in Recreationally Active Women

    Science.gov (United States)

    Varanoske, Alyssa N.; Hoffman, Jay R.; Church, David D.; Baker, Kayla M.; Dodd, Sarah J.; Coker, Nicholas A.; Oliveira, Leonardo P.; Dawson, Virgil L.; Stout, Jeffrey R.

    2017-01-01

    Carnosine is a naturally occurring intramuscular dipeptide that is thought to attenuate fatigue during high-intensity exercise. Carnosine content is influenced by various factors, including gender and diet. Despite research reporting that carnosine content is lower in women compared to men and lower in vegetarians compared to omnivores, no investigations have examined carnosine content in women based on dietary protein intake and its effect on muscle fatigue. Twenty recreationally active women were assigned to either a high (HI; n = 5), moderate (MOD; n = 10), or low (LO; n = 5) group based upon intramuscular carnosine content of the vastus lateralis. Each participant underwent two unilateral maximal voluntary isometric contractions (MVIC) of the knee extensors separated by an isokinetic exercise protocol consisting of five sets of 50 repeated maximal unilateral contractions. Magnitude-based inferences were used to analyze group differences. Percent decline in rate of force development and peak torque (PT) during the MVICs and changes in PT and mean torque during the muscle-fatiguing protocol were lower in HI compared to both MOD and LO. Additionally, absolute and relative dietary protein intake were greater in HI compared to MOD or LO. Results indicated that greater intramuscular carnosine content was reflective of greater dietary protein intake and that individuals with higher carnosine content displayed a greater attenuation of fatigue compared to those with lower carnosine. PMID:28880219

  5. Force steadiness, muscle activity, and maximal muscle strength in subjects with subacromial impingement syndrome

    DEFF Research Database (Denmark)

    Bandholm, Thomas; Rasmussen, Lars; Aagaard, Per

    2006-01-01

    physically active in spite of shoulder pain and nine healthy matched controls were examined to determine isometric and isokinetic submaximal shoulder-abduction force steadiness at target forces corresponding to 20%, 27.5%, and 35% of the maximal shoulder abductor torque, and maximal shoulder muscle strength......We investigated the effects of the subacromial impingement syndrome (SIS) on shoulder sensory-motor control and maximal shoulder muscle strength. It was hypothesized that both would be impaired due to chronic shoulder pain associated with the syndrome. Nine subjects with unilateral SIS who remained...

  6. Physiotherapy and Rehabilitation Interventions in the Conservative Treatment of Chondrocalcinosis: A Case Report

    Directory of Open Access Journals (Sweden)

    Bihter Akınoğlu

    2017-09-01

    Full Text Available Chondrocalcinosis is defined as the accumulation of crystals of calcium pyrophosphate in the hyaline cartilage and fibrous tissue. A 24 years old tennis player referred to our clinic with chondrocalcinosis diagnosis, for conservative treatment. On admission, she had pain and difficulty in walking, stair climbing and sitting up, as well as weakness in front thigh muscles. High voltage galvanic stimulation, isokinetic strength training and home exercises were applied two days a week for six weeks. Following the treatment, there were significant improvements in her daily life activities and quadriceps muscle strength.

  7. Novel mass spectrometric instrument for gaseous and particulate characterization and monitoring

    International Nuclear Information System (INIS)

    Coggiola, M.J.

    1993-04-01

    Under contract DE-AC21-92MC29116, SRI International will develop a unique new instrument that will be capable of providing real-time (< l minute), quantitative, chemical characterization of gaseous and particulate pollutants generated from DOE waste cleanup activities. The instrument will be capable of detecting and identifying volatile organic compounds, polynuclear aromatic hydrocarbons, heavy metals, and transuranic species released during waste cleanup activities. The instrument will be unique in its ability to detect and quantify in real-time these diverse pollutants in both vapor and particulate form. The instrument to be developed under this program will consist of several major components: (1) an isokinetic sampler capable of operating over a wide range of temperatures (up to 500 K) and flow rates; (2) a high pressure to low pressure transition and sampling region that efficiently separates particles from vapor-phase components for separate, parallel analyses; (3) two small mass spectrometers, one optimized for organic analysis using a unique field ionization source and one optimized for particulate characterization using thermal pyrolysis and electron-impact ionization (EI); and (4) a powerful personal computer for control and data acquisition

  8. The effects of passive leg press training on jumping performance, speed, and muscle power.

    Science.gov (United States)

    Liu, Chiang; Chen, Chuan-Shou; Ho, Wei-Hua; Füle, Róbert János; Chung, Pao-Hung; Shiang, Tzyy-Yuang

    2013-06-01

    Passive leg press (PLP) training was developed based on the concepts of the stretch-shortening cycle (SSC) and the benefits of high muscle contraction velocity. Passive leg press training enables lower limb muscle groups to apply a maximum downward force against a platform moved up and down at high frequency by an electric motor. Thus, these muscle groups accomplished both concentric and eccentric isokinetic contractions in a passive, rapid, and repetitive manner. This study investigates the effects of 10 weeks of PLP training at high and low movement frequencies have on jumping performance, speed, and muscle power. The authors selected 30 college students who had not performed systematic resistance training in the previous 6 months, including traditional resistance training at a squat frequency of 0.5 Hz, PLP training at a low frequency of 0.5 Hz, and PLP training at a high frequency of 2.5 Hz, and randomly divided them into 3 groups (n = 10). The participants' vertical jump, drop jump, 30-m sprint performance, explosive force, and SSC efficiency were tested under the same experimental procedures at pre- and post-training. Results reveal that high-frequency PLP training significantly increased participants' vertical jump, drop jump, 30-m sprint performance, instantaneous force, peak power, and SSC efficiency (p training (p training significantly increased participants' vertical jump, 30-m sprint performance, instantaneous force, and peak power (p training only increased participants' 30-m sprint performance and peak power (p training at high movement frequency. A PLP training machine powered by an electrical motor enables muscles of the lower extremities to contract faster compared with voluntary contraction. Therefore, muscle training with high contraction velocity is one of the main methods of increasing muscle power. Passive leg press training is a unique method for enhancing jump performance, speed, and muscle power.

  9. Kinematic Mechanisms of How Power Training Improves Healthy Old Adults' Gait Velocity.

    Science.gov (United States)

    Beijersbergen, Chantal M I; Granacher, Urs; Gäbler, Martijn; Devita, Paul; Hortobágyi, Tibor

    2017-01-01

    Slow gait predicts many adverse clinical outcomes in old adults, but the mechanisms of how power training can minimize the age-related loss of gait velocity is unclear. We examined the effects of 10 wk of lower extremity power training and detraining on healthy old adults' lower extremity muscle power and gait kinematics. As part of the Potsdam Gait Study, participants started with 10 wk of power training followed by 10 wk of detraining (n = 16), and participants started with a 10-wk control period followed by 10 wk of power training (n = 16). We measured gait kinematics (stride characteristic and joint kinematics) and isokinetic power of the ankle plantarflexor (20°·s, 40°·s, and 60°·s) and knee extensor and flexor (60°·s, 120°·s, and 180°·s) muscles at weeks 0, 10, and 20. Power training improved isokinetic muscle power by ~30% (P ≤ 0.001) and fast (5.9%, P kinematics did not correlate with increases in fast gait velocity. The mechanisms that increased fast gait velocity involved higher cadence (r = 0.86, P ≤ 0.001) rather than longer strides (r = 0.49, P = 0.066). Detraining did not reverse the training-induced increases in muscle power and fast gait velocity. Because increases in muscle power and modifications in joint kinematics did not correlate with increases in fast gait velocity, kinematic mechanisms seem to play a minor role in improving healthy old adults' fast gait velocity after power training.

  10. A 12-week rehabilitation program improves body composition, pain sensation, and internal/external torques of baseball pitchers with shoulder impingement symptom.

    Science.gov (United States)

    Cha, Jun-Youl; Kim, Jae-Hak; Hong, Ju; Choi, Young-Tae; Kim, Min-Ho; Cho, Ji-Hyun; Ko, Il-Gyu; Jee, Yong-Seok

    2014-02-01

    The aim of this study was to investigate the effects of a 12-week rehabilitation program on body composition, shoulder pain, and isokinetic internal/external torques of pitchers with impingement syndrome. A total of 30 pitchers were divided into 2 groups: experimental group (EG, n = 16) and control group (CG, n= 14). The rehabilitation program consisted of physical therapy, warm-up, work-out, and cool-down. As results, body weight and fat mass of EG were decreased whereas muscle mass of EG was significantly increased after the experiment. The pain degrees in resting, normal daily activity, and strenuous activity on the numeric pain rating scale were significantly decreased in the EG. The internal and external peak torques (PTs) of uninvolved and involved sides of EG were increased in EG after 12 weeks. Such results provide a deficit ratio of both sides in EG close to normal values. The ratios of internal/external PTs in EG were also close to the reference values. The internal and external total works of both sides in EG were similar to the values of PT. The fatigue indices of internal and external rotators of both sides in EG were decreased. As a conclusion, a 12-week rehabilitation program reduced the shoulder pain, improved the body composition and enhanced the isokinetic shoulder internal/external rotators in EG with impingement symptoms. Also the study suggested that the rehabilitation program evened out the ratio between internal and external rotators and lowered the fatigue level after the experiment.

  11. Effects of Resistance Training on Muscle Strength, Endurance, and Motor Unit According to Ciliary Neurotrophic Factor Polymorphism in Male College Students

    Directory of Open Access Journals (Sweden)

    Ae-Rim Hong, Sang-Min Hong, Yun-A Shin

    2014-09-01

    Full Text Available Changes in muscle mass and strength across the adult age span are variable and related to the ciliary neurotrophic factor (CNTF genotype. In particular, a single CNTF haplotype (1357 G→A is important for neuronal and muscular developments and may be associated with muscle strength response to resistance training. We examined whether CNTF genotype differentially influences the effect of resistance training on neuromuscular improvement in male college students. Resistance training of the upper extremities comprised 3 sets at 75%–85% intensity per 1 repetition maximum, 3 times a week, for a total of 8 weeks. We measured isokinetic muscle function of the elbow joint with regard to strength (60°/s and endurance (180°/s by using an isokinetic dynamometer. The biceps brachii (BB and brachioradialis muscles were studied using surface electromyography with spike-triggered averaging to assess surface-detected motor unit potential (SMUP area. After resistance training, the SMUP of the BB increased significantly at 60°/s (p < 0.05, but no difference in the CNTF genotype was observed. The SMUP of the BB at 180°/s increased significantly in the GG/AA genotype group compared with that in the GA genotype group (p < 0.05. The average power of the elbow flexor at 180°/s increased significantly after resistance training (p < 0.05, but again, no difference in the CNTF genotype was observed. Thus, improvements in muscle strength and endurance may have resulted directly from resistance training rather than from genetic factors related to nerves in muscle tissue.

  12. Do functional tests predict low back pain?

    Science.gov (United States)

    Takala, E P; Viikari-Juntura, E

    2000-08-15

    A cohort of 307 nonsymptomatic workers and another cohort of 123 workers with previous episodes of low back pain were followed up for 2 years. The outcomes were measured by symptoms, medical consultations, and sick leaves due to low back disorders. To study the predictive value of a set of tests measuring the physical performance of the back in a working population. The hypothesis was that subjects with poor functional capacity are liable to back disorders. Reduced functional performance has been associated with back pain. There are few data to show whether reduced functional capacity is a cause or a consequence of pain. Mobility of the trunk in forward and side bending, maximal isokinetic trunk extension, flexion and lifting strength, and static endurance of back extension were measured. Standing balance and foot reaction time were recorded with a force plate. Clinical tests for the provocation of back or leg pain were performed. Gender, workload, age, and anthropometrics were managed as potential confounders in the analysis. Marked overlapping was seen in the measures of the subjects with different outcomes. Among the nonsymptomatic subjects, low performance in tests of mobility and standing balance was associated with future back disorders. Among workers with previous episodes of back pain, low isokinetic extension strength, poor standing balance, and positive clinical signs predicted future pain. Some associations were found between the functional tests and future low back pain. The wide variation in the results questions the value of the tests in health examinations (e.g., in screening or surveillance of low back disorders).

  13. Reliability of a functional test battery evaluating functionality, proprioception, and strength in recreational athletes with functional ankle instability.

    Science.gov (United States)

    Sekir, U; Yildiz, Y; Hazneci, B; Ors, F; Saka, T; Aydin, T

    2008-12-01

    In contrast to the single evaluation methods used in the past, the combination of multiple tests allows one to obtain a global assessment of the ankle joint. The aim of this study was to determine the reliability of the different tests in a functional test battery. Twenty-four male recreational athletes with unilateral functional ankle instability (FAI) were recruited for this study. One component of the test battery included five different functional ability tests. These tests included a single limb hopping course, single-legged and triple-legged hop for distance, and six and cross six meter hop for time. The ankle joint position sense and one leg standing test were used for evaluation of proprioception and sensorimotor control. The isokinetic strengths of the ankle invertor and evertor muscles were evaluated at a velocity of 120 degrees /s. The reliability of the test battery was assessed by calculating the intraclass correlation coefficient (ICC). Each subject was tested two times, with an interval of 3-5 days between the test sessions. The ICCs for ankle functional and proprioceptive ability showed high reliability (ICCs ranging from 0.94 to 0.98). Additionally, isokinetic ankle joint inversion and eversion strength measurements represented good to high reliability (ICCs between 0.82 and 0.98). The functional test battery investigated in this study proved to be a reliable tool for the assessment of athletes with functional ankle instability. Therefore, clinicians may obtain reliable information from the functional test battery during the assessment of ankle joint performance in patients with functional ankle instability.

  14. [Does transcutaneous electrical nerve stimulation or therapeutic ultrasound increase the effectiveness of exercise for knee osteoarthritis: a randomized controlled study].

    Science.gov (United States)

    Eyigör, Sibel; Karapolat, Hale; Ibisoğlu, Uğur; Durmaz, Berrin

    2008-01-01

    The aim of this study was to determine if transcutaneous electrical nerve stimulation (TENS) or therapeutic ultrasound (US) increase the effectiveness of exercise on pain, function, muscle strength and quality of life for knee osteoarthritis (OA). Forty-five patients with primary knee OA diagnosis according to American College Rheumatology criteria were sequentially divided into 3 random groups. The patients in group 1 received TENS (with superficial heat and exercise), group 2 received US (with superficial heat and exercise), and group 3 acted as controls (superficial heat and exercise). Outcome measures were included as visual analog scale (VAS), a 20-meter walking test, Lequesne index, WOMAC scores, isokinetic muscle testing, and the Short Form 36 (SF 36). All treatment groups, physical modalities were carried out for a total fifteen sessions. All of the patients were subjected to six weeks of exercise program. All of the treatment groups had significant improvement on activity VAS, 20 meter walking test, Lequesne index, WOMAC scores, and most of the sub-scores of SF36 when compared with their initial status (p0.05). All of the treatment groups were effective on pain, function, muscle strength and quality of life in patients with knee OA. Statistically significant differences could not be found between the treatment groups. The exercise program, as it is cheaper, more easily performed and efficient, may be preferable for the treatment of knee OA. It is difficult to say, TENS or US could increase the effectiveness of isokinetic exercise for pain, function, muscle strength and quality of life of knee OA in this study.

  15. Balance and Muscle Strength in Elderly Women Who Dance Samba.

    Directory of Open Access Journals (Sweden)

    Marcos Maurício Serra

    Full Text Available Considering the growth of the aging population, and the increasing risk for falls and related morbidity, it is vital to seek efficient, comprehensive, and culturally relevant prevention programs for elderly people to reduce risks for falls. The aim of the present study was to evaluate the postural balance and muscle strength among women participating in the "Wing of Baianas" in the carnival parades. One hundred and ten women, with an average age of 67.4±5.9 years, were divided into two groups: Baianas group-elderly participants of the carnival parades in the "Wing of Baianas", and a Control group of women who do not dance samba. Assessments included a physical activity questionnaire, isokinetic muscle strength testing for the knee extensors and flexors, and a postural balance assessment completed on a force platform. There were no differences between groups, for postural balance outcomes, during the eyes open condition; however, with eyes closed, there was a significant effect between groups (Baianas vs Control in all variables. The Baianas group showed less medio-lateral displacement (p < 0.04; and anteroposterior displacement (p < 0.007; larger amplitudes of medio-lateral displacement (p < 0.001; and anteroposterior displacement (p < 0.001; increased mean velocity (p < 0.01; and elliptical area (p < 0.01 There were no differences in the isokinetic peak torque corrected by body weight, total work and flexor/extensor ratio. Participation in the Wing of Baianas is associated with better balance with closed eyes, but there were no differences between dancers and non-dancers for muscle strength.

  16. Test-retest reliability of knee extensor rate of velocity and power development in older adults using the isotonic mode on a Biodex System 3 dynamometer.

    Science.gov (United States)

    Van Driessche, Stijn; Van Roie, Evelien; Vanwanseele, Benedicte; Delecluse, Christophe

    2018-01-01

    Isotonic testing and measures of rapid power production are emerging as functionally relevant test methods for detection of muscle aging. Our objective was to assess reliability of rapid velocity and power measures in older adults using the isotonic mode of an isokinetic dynamometer. Sixty-three participants (aged 65 to 82 years) underwent a test-retest protocol with one week time interval. Isotonic knee extension tests were performed at four different loads: 0%, 25%, 50% and 75% of maximal isometric strength. Peak velocity (pV) and power (pP) were determined as the highest values of the velocity and power curve. Rate of velocity (RVD) and power development (RPD) were calculated as the linear slopes of the velocity- and power-time curve. Relative and absolute measures of test-retest reliability were analyzed using intraclass correlation coefficients (ICC), standard error of measurement (SEM) and Bland-Altman analyses. Overall, reliability was high for pV, pP, RVD and RPD at 0%, 25% and 50% load (ICC: .85 - .98, SEM: 3% - 10%). A trend for increased reliability at lower loads seemed apparent. The tests at 75% load led to range of motion failure and should be avoided. In addition, results demonstrated that caution is advised when interpreting early phase results (first 50ms). To conclude, our results support the use of the isotonic mode of an isokinetic dynamometer for testing rapid power and velocity characteristics in older adults, which is of high clinical relevance given that these muscle characteristics are emerging as the primary outcomes for preventive and rehabilitative interventions in aging research.

  17. Musculoskeletal profile of middle-aged Ving Tsun Chinese martial art practitioners

    Science.gov (United States)

    Fong, Shirley S.M.; Chan, Jessie S.M.; Bae, Young-Hyeon; Yam, Timothy T.T.; Chung, Louisa M.Y.; Ma, Ada W.W.; Kuisma, Raija

    2017-01-01

    Abstract This cross-sectional exploratory study aimed to quantify and compare the axial and appendicular bone mineral density (BMD), muscle mass, and muscle strength of middle-aged practitioners of Ving Tsun (VT; a hard-style Chinese martial art) with those of nonpractitioners. Eighteen VT practitioners (mean age ± standard deviation = 51.8 ± 17.7 years; 12 men and six women) and 36 active controls (mean age ± standard deviation = 58.7 ± 11.0 years; 18 men and 18 women) participated in the study. All participants underwent a 1-day battery of musculoskeletal examinations. The BMD of the total radius, total hip, femoral neck, and lumbar spine was measured using dual-energy X-ray absorptiometry, as was the lean mass of the arm, leg, and trunk. Muscle strength of the upper and lower limbs was assessed using a Jamar dynamometer and an isokinetic dynamometer at 60°/second, respectively. VT-trained participants had a 11.5% higher total radius BMD (P = 0.023), a 17.8% higher leg lean mass (P = 0.014), a 56.4% higher isokinetic body weight-adjusted peak torque of the knee extensors (P  0.05). Middle-aged VT practitioners displayed a higher total radius BMD and leg lean mass and better knee extensor and flexor muscular performances than their healthy active counterparts. Healthcare professionals may consider using this alternative method of training to improve the musculoskeletal health of middle-aged adults. PMID:28121945

  18. Correlation of proliferative and clonogenic tumor cells in multiple myeloma

    International Nuclear Information System (INIS)

    Karp, J.E.; Burke, P.J.; Saylor, P.L.; Humphrey, R.L.

    1984-01-01

    To expand on the findings from previous clinical trials that the growth of residual tumor is increased at a predictable time following initial drug administration, malignant plasma cells from bone marrows of patients with multiple myeloma (MM) were examined for changes in proliferation and clonogenicity induced in vivo by cyclophosphamide and in vitro by drug-induced humoral stimulatory activity. Peak plasma cell [ 3 H]thymidine labeling index (LI) occurred predictably following drug and paralleled changes in agar colony formation by marrow cells obtained during therapy. Colony-forming capacity of pretreatment MM marrow populations was enhanced when those cells were cultured with humoral stimulatory activity, similar to the increased colony formation detected in Day 9 postcyclophosphamide marrows at the time of peak plasma cell LI. To further define a relationship between proliferative plasma cells and colony-forming tumor cells, MM marrows were fractionated by sedimentation on an isokinetic gradient. Enrichment of a proliferative tumor cell cohort was achieved, evidenced by [ 3 H]thymidine LI. Colony-forming cells were also enriched by isokinetic gradient sedimentation, and agar colony formation by MM marrow cell fractions correlated with the kinetic characteristics of the isolated subpopulations. These studies of whole and fractionated human MM marrow cell populations suggest that the kinetically active cells which are induced to proliferate in vivo and in vitro are closely related to the clonogenic tumor cells which produce colonies in agar and which, like those cells measured by [ 3 H]thymidine LI, respond to growth stimulation by drug-induced humoral stimulatory activity

  19. Kinetic study by FTIR and DSC on the cationic curing of a DGEBA/{gamma}-valerolactone mixture with ytterbium triflate as an initiator

    Energy Technology Data Exchange (ETDEWEB)

    Arasa, M. [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili. C/Marcel.li Domingo s/n, 43007 Tarragona (Spain); Ramis, X. [Laboratori de Termodinamica, ETSEIB. Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain)], E-mail: ramis@mmt.upc.edu; Salla, J.M. [Laboratori de Termodinamica, ETSEIB. Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Mantecon, A.; Serra, A. [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili. C/Marcel.li Domingo s/n, 43007 Tarragona (Spain)

    2008-12-05

    A mixture of diglycidylether of bisphenol A (DGEBA) and {gamma}-valerolactone ({gamma}-VL) was cured in the presence of ytterbium triflate as an initiator to obtain poly(esther-ether) thermosets. The kinetics of the various elemental reactions, which take place during the curing process, was studied by means of isothermal curing in the FTIR spectrometer. The kinetic parameters were calculated by means of the isoconversional procedure and the best-fit kinetic model was determined with the so-called compensation effect (isokinetic relationship). The isothermal kinetic analysis was compared with that obtained by dynamic curing in DSC.

  20. Power of the muscular group's taekwondokas of the different qualification in steady-state mode.

    Directory of Open Access Journals (Sweden)

    Saienko Vladimir Grigor'evich

    2011-11-01

    Full Text Available Data are given meaningful totals display of force the muscle groups in athletes in the static mode. Displaying characteristics of muscle groups, hands (7, legs (5, trunk (2.The experiment involved 110 athletes (1-5 years experience training, age - 14-25 years old. Quantitative indicators, which reflect the individual level of informative power trained athletes. The optimum parameters of power qualities of athletes. Recommended use in training of special methods of strength training (isometric, concentric, eccentric, plyometric, isokinetic. In training must take into account the resistance, speed, joint angles, number of repetitions of the same approach.

  1. Impact of high intensity exercise on muscle morphology in EAE rats

    DEFF Research Database (Denmark)

    Wens, I; Dalgas, U; Verboven, K

    2015-01-01

    paralysis (experiment 2, n=40), isokinetic foot extensor strength, cross sectional area (CSA) of tibialis anterior (TA), extensor digitorum longus (EDL) and soleus (SOL) and brain-derived neurotrophic factor (BDNF) levels were assessed. EAE reduced muscle fiber CSA of TA, EDL and SOL. In general, exercise...... was not able to affect CSA, whereas it delayed hindquarter paralysis peak. CON muscle work peaked and declined, while it remained stable in EAE. BDNF-responses were not affected by EAE or exercise. In conclusion, EAE affected CSA-properties of TA, EDL and SOL, which could, partly, explain the absence of peak...

  2. Interpretation and consequences of Meyer-Neldel rule for conductivity of phase change alloys

    Energy Technology Data Exchange (ETDEWEB)

    Savransky, S.D. [The TRIZ Experts, 6015 Peppertree Court, Newark, CA 94560 (United States); Yelon, A. [Department of Engineering Physics and Reseau Quebecois de Materiaux de Pointe, Ecole Polytechnique, P.O. Box 6079, Station C-V Montreal, Quebec (Canada)

    2010-03-15

    Measurements of conductivity as a function of temperature were performed on a large number of memory cells of a GeSbTe phase change memory alloy, in both the set and reset states. Conductivity obeys the Meyer-Neldel rule in both states, with the same Meyer-Neldel, or isokinetic, temperature, but with conductivity prefactors about six orders of magnitude larger in the set than in the reset state. These observations are interpreted in terms of the multiexcitation entropy model, and conduction mechanisms are suggested. Their effect on the expected behavior of memories is considered. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  3. Kinetic study by FTIR and DSC on the cationic curing of a DGEBA/γ-valerolactone mixture with ytterbium triflate as an initiator

    International Nuclear Information System (INIS)

    Arasa, M.; Ramis, X.; Salla, J.M.; Mantecon, A.; Serra, A.

    2008-01-01

    A mixture of diglycidylether of bisphenol A (DGEBA) and γ-valerolactone (γ-VL) was cured in the presence of ytterbium triflate as an initiator to obtain poly(esther-ether) thermosets. The kinetics of the various elemental reactions, which take place during the curing process, was studied by means of isothermal curing in the FTIR spectrometer. The kinetic parameters were calculated by means of the isoconversional procedure and the best-fit kinetic model was determined with the so-called compensation effect (isokinetic relationship). The isothermal kinetic analysis was compared with that obtained by dynamic curing in DSC

  4. Development of a wet gas flowmeter

    Energy Technology Data Exchange (ETDEWEB)

    Andreussi, P.; Ciandri, P.; Faluomi, V. [TRA Sistemi, Pisa (Italy)

    2000-07-01

    A new multiphase flowmeter, particularly suited for wet gas metering, has been developed. The meter working principle is the isokinetic sampling of the gas-liquid mixture, followed by separation and individual metering of the gas and the liquid phase. The liquid flowrate is derived from the value of the sampled liquid flowrate. The gas flowrate is measured with a multiphase nozzle. Preliminary tests have shown that both the gas and the liquid flowrates can be determined with an error less than 5%. The meter can be autocalibrated and allows the water-cut to be measured with any prescribed precision. (author)

  5. Toutle/Cowlitz River Sediment Budget

    Science.gov (United States)

    2010-05-18

    the stream width, expressed as Watts per square meter (W/m2). Brookes (1987) found that in streams 25 30 35 40 45 50 Jun-68 Dec-73 May-79 Nov-84...0.0100 0.1000 0.1 1.0 10.0 100.0 En er gy S lo pe (m /m ) Bankfull Discharge per Unit Width, (cubic meters /sec-m) North Fork Above SRS North Fork Below...at 5 feet per second, however, Gray et al. (2009) report that the FISP series of isokinetic samplers is calibrated to 3.9 feet per second. As shown

  6. Striated muscle fiber size, composition and capillary density in diabetes in relation to neuropathy and muscle strength

    DEFF Research Database (Denmark)

    Andreassen, Christer Swan; Jensen, Jacob Malte; Jakobsen, Johannes

    2014-01-01

    study was to evaluate histologic properties and capillarization of diabetic skeletal muscle in relation to DPN and muscle strength. METHODS: Twenty type 1 and 20 type 2 diabetic (T1D and T2D, respectively) patients underwent biopsy of the gastrocnemic muscle, isokinetic dynamometry at the ankle...... between muscle fiber diameter, muscle fiber type distribution, or capillary density and degree of neuropathy or muscle strength for either patient group. Muscle fiber diameter and the proportion of Type II fibers were greater for T1D patients than both T2D patients and controls. The T2D patients had fewer...

  7. Estudo de associação entre força muscular e massa magra em mulheres idosas Estudio de la asociación entre fuerza muscular y masa magra en mujeres mayores Association between muscle strength and fat-free mass in older women

    Directory of Open Access Journals (Sweden)

    Ricardo Moreno Lima

    2012-12-01

    Full Text Available O objetivo do presente estudo foi verificar a associação entre a força muscular isocinética da musculatura extensora do joelho do membro dominante com a MM de diferentes segmentos corporais, em mulheres idosas. Um total de 258 idosas (66,58±5,6anos; 65,6±11,7kg; 1,53±0,07m foram submetidas à avaliação isocinética do pico de torque (PT e da MM (DXA. Correlações de Pearson foram examinadas entre os índices de MM dos braços, das pernas, do tronco, do corpo inteiro, da perna dominante (MMB, MMP, MMT, MMI, MMPD, respectivamente com o PT. O nível de significância foi de El objetivo de este estudio fue correlacionar la fuerza muscular de los extensores de la rodilla con la Masa Magra (MM en diferentes segmentos corporales en mujeres mayores. 258 mujeres mayores (66,58±5,6años; 65,6±11,7kg; 1,53±0,07m fueron someter a la evaluación del pico de torque (PT en el dinamómetro (Biodex y de la MM (DXA. Correlaciones de Pearson se realizó entre la MM de los brazos, piernas, tronco, el cuerpo entero, de la pierna dominante (MMB, MMPs, MMT, MMCI, MMPD, respectivamente con el PT. La MM de todas regiones examinadas presentaron correlación positiva y significante con los valores del PT (pThe purpose of the present study was to correlate knee extensors muscle strength with fat-free mass (FFM of different body sites in older women. Peak torque (PT from 258 women (66.58±5.6years; 65.6±11.7kg; 1.53±0.07m was assessed using an isokinetic dynamometer (Biodex and FFM was evaluated using dual-energy x-ray absorptiometry (DXA. Pearson correlations were performed between FFM from Arms, Legs, Thorax, Whole Body and Dominant Leg (FFMA, FFMLs, FFMT, FFMWB and FFMDL, respectively with PT. Significance level was set at α <0.05 for all comparisons. Positive and significant correlations were observed between FFM from all sites and isokinetic PT (p<0.001. However, it was stronger when the site of FFM analyzed was closer to the muscle responsible to

  8. Lower limb strength in professional soccer players: profile, asymmetry, and training age.

    Science.gov (United States)

    Fousekis, Konstantinos; Tsepis, Elias; Vagenas, George

    2010-01-01

    Kicking and cutting skills in soccer are clearly unilateral, require asymmetrical motor patterns and lead to the development of asymmetrical adaptations in the musculoskeletal function of the lower limbs. Assuming that these adaptations constitute a chronicity-dependent process, this study examined the effects of professional training age (PTA) on the composite strength profile of the knee and ankle joint in soccer players. One hundred soccer players (n=100) with short (5-7 years), intermediate (8-10 years) and long (>11 years) PTA were tested bilaterally for isokinetic concentric and eccentric strength of the knee and ankle muscles. Knee flexion-extension was tested concentrically at 60°, 180° and 300 °/sec and eccentrically at 60° and 180 °/sec. Ankle dorsal and plantar flexions were tested at 60 °/sec for both the concentric and eccentric mode of action. Bilaterally averaged muscle strength [(R+L)/2] increased significantly from short training age to intermediate and stabilized afterwards. These strength adaptations were mainly observed at the concentric function of knee extensors at 60°/sec (p = 0. 023), knee flexors at 60°/sec (p = 0.042) and 180°/sec (p = 0.036), and ankle plantar flexors at 60o/sec (p = 0.044). A linear trend of increase in isokinetic strength with PTA level was observed for the eccentric strength of knee flexors at 60°/sec (p = 0.02) and 180°/sec (p = 0.03). Directional (R/L) asymmetries decreased with PTA, with this being mainly expressed in the concentric function of knee flexors at 180°/sec (p = 0.04) and at 300 °/sec (p = 0.03). These findings confirm the hypothesis of asymmetry in the strength adaptations that take place at the knee and ankle joint of soccer players mainly along with short and intermediate PTA. Players with a longer PTA seem to adopt a more balanced use of their lower extremities to cope with previously developed musculoskeletal asymmetries and possibly reduce injury risk. This has certain implications

  9. CHARACTERISTICS OF MAXIMUM PERFORMANCE OF PEDALING EXERCISE IN RECUMBENT AND SUPINE POSITIONS

    Directory of Open Access Journals (Sweden)

    Morimasa Kato

    2011-09-01

    Full Text Available To determine the characteristics of maximum pedaling performance in the recumbent and supine positions, maximum isokinetic leg muscle strength was measured in eight healthy male subjects during pedaling at three velocities (300°/s, 480°/s, and 660°/s, and maximum incremental tests were performed for each position. The maximum isokinetic muscle strength in the recumbent position was 210.0 ± 29.2 Nm at 300°/s, 158.4 ± 19.8 Nm at 480°/s, and 110.6 ± 13.2 at 660°/s. In contrast, the muscle strength in the supine position was 229.3 ± 36.7 Nm at 300°/s, 180. 7 ± 20.3 Nm at 480°/s, and 129.6 ± 14.0 Nm at 660°/s. Thus, the maximum isokinetic muscle strength showed significantly higher values in the supine position than in the recumbent position at all angular velocities. The knee and hip joint angles were measured at peak torque using a goniometer; the knee joint angle was not significantly different between both positions, whereas the hip joint angle was greater in the supine position than in the recumbent position (Supine position: 137.3 ± 9. 33 degree at 300°/s, 140.0 ± 11.13 degrees at 480°/s, and 141.0 ± 9.61 degrees at 660°/s. Recumbent position: 99.5 ± 12.21 degrees at 300°/s, 101.6 ± 12.29 degrees at 480°/s, and 105.8 ± 14.28 degrees at 660°/s. Peak oxygen uptake was higher in the recumbent position (50.3 ± 4.43 ml·kg-1·min-1 than in the supine position (48.7 ± 5.10 ml·kg-1·min-1. At maximum exertion, the heart rate and whole-body rate of perceived exertion (RPE were unaffected by position, but leg muscle RPE was higher in the supine position (19.5 ± 0.53 than in the recumbent position (18.8 ± 0.71. These results suggest that the supine position is more suitable for muscle strength exertion than the recumbent position, and this may be due to different hip joint angles between the positions. On the contrary, the endurance capacity was higher in the recumbent position than in the supine position. Since leg muscle

  10. EFFECT OF HEAT PRECONDITIONING BY MICROWAVE HYPERTHERMIA ON HUMAN SKELETAL MUSCLE AFTER ECCENTRIC EXERCISE

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    Norio Saga

    2008-03-01

    Full Text Available The purpose of this study was to clarify whether heat preconditioning results in less eccentric exercise-induced muscle damage and muscle soreness, and whether the repeated bout effect is enhanced by heat preconditioning prior to eccentric exercise. Nine untrained male volunteers aged 23 ± 3 years participated in this study. Heat preconditioning included treatment with a microwave hyperthermia unit (150 W, 20 min that was randomly applied to one of the subject's arms (MW; the other arm was used as a control (CON. One day after heat preconditioning, the subjects performed 24 maximal isokinetic eccentric contractions of the elbow flexors at 30°·s-1 (ECC1. One week after ECC1, the subjects repeated the procedure (ECC2. After each bout of exercise, maximal voluntary contraction (MVC, range of motion (ROM of the elbow joint, upper arm circumference, blood creatine kinase (CK activity and muscle soreness were measured. The subjects experienced both conditions at an interval of 3 weeks. MVC and ROM in the MW were significantly higher than those in the CON (p < 0.05 for ECC1; however, the heat preconditioning had no significant effect on upper arm circumference, blood CK activity, or muscle soreness following ECC1 and ECC2. Heat preconditioning may protect human skeletal muscle from eccentric exercise-induced muscle damage after a single bout of eccentric exercise but does not appear to promote the repeated bout effect after a second bout of eccentric exercise

  11. Aplicación de la dinamometría isocinética para establecer perfiles de riesgo de lesión isquiosural en futbolistas profesionales. [The use of isokinetic dynamometry to establish risk profiles of hamstring injury in professional football players].

    Directory of Open Access Journals (Sweden)

    Victor Moreno-Perez

    2013-10-01

    torque of the hamstring musculature was found, are useful variables to establish risk profiles for hamstring injury in professional football players. Twenty players of a Second Division team of the Liga de Fútbol Profesional bilaterally performed an isokinetic test of eccentric knee flexion at 30º/s and concentric knee extension at 240º/s during the pre-season. The Flexexc30/Extcon240 ratio and the knee angle of peak torque were calculated, and the players’ injuries were registered throughout the season. The results showed that two of the five injured players had Flexexc30/Extcon240 ratios lower than 0.89, value that has been previously used to determine the imbalance between knee flexor and extensor strength and the risk of injury (Croisier, Ganteaume, Binet, Genty, and Ferret, 2008. In addition, another two injured players obtained ratios between 0.93 and 1.00. On the other hand, no differences in the knee angle of peak torque between injured and non-injured players were found. These results indicate that the Flexexc30/Extcon240 ratio may be a useful index to determine the risk of hamstring injury in professional football players.http://dx.doi.org/10.5232/ricyde2013.03403

  12. Evaluation of intake efficiencies and associated sediment-concentration errors in US D-77 bag-type and US D-96-type depth-integrating suspended-sediment samplers

    Science.gov (United States)

    Sabol, Thomas A.; Topping, David J.

    2013-01-01

    Accurate measurements of suspended-sediment concentration require suspended-sediment samplers to operate isokinetically, within an intake-efficiency range of 1.0 ± 0.10, where intake efficiency is defined as the ratio of the velocity of the water through the sampler intake to the local ambient stream velocity. Local ambient stream velocity is defined as the velocity of the water in the river at the location of the nozzle, unaffected by the presence of the sampler. Results from Federal Interagency Sedimentation Project (FISP) laboratory experiments published in the early 1940s show that when the intake efficiency is less than 1.0, suspended-sediment samplers tend to oversample sediment relative to water, leading to potentially large positive biases in suspended-sediment concentration that are positively correlated with grain size. Conversely, these experiments show that, when the intake efficiency is greater than 1.0, suspended‑sediment samplers tend to undersample sediment relative to water, leading to smaller negative biases in suspended-sediment concentration that become slightly more negative as grain size increases. The majority of FISP sampler development and testing since the early 1990s has been conducted under highly uniform flow conditions via flume and slack-water tow tests, with relatively little work conducted under the greater levels of turbulence that exist in actual rivers. Additionally, all of this recent work has been focused on the hydraulic characteristics and intake efficiencies of these samplers, with no field investigations conducted on the accuracy of the suspended-sediment data collected with these samplers. When depth-integrating suspended-sediment samplers are deployed under the more nonuniform and turbulent conditions that exist in rivers, multiple factors may contribute to departures from isokinetic sampling, thus introducing errors into the suspended-sediment data collected by these samplers that may not be predictable on the basis

  13. Força muscular isocinética de jogadores de futebol da seleção paraolímpica brasileira de portadores de paralisia cerebral Fuerza muscular isocinética en jugadores de futbol de la selección paraolímpica brasileña de portadores de parálisis cerebral Isokinetic muscular strength of paralympic athletes with cerebral palsy (CP from the Brazilian soccer team

    Directory of Open Access Journals (Sweden)

    Marília dos Santos Andrade

    2005-10-01

    fué utilizado para analizar la deficiencia contra-lateral en relación entre los músculos flexores y extensores de la rodilla y la flaqueza muscular comparados con valores previstos para individuos normales (Neder et al., 1999. El test t-Student apareado fué utilizado para el análisis estadístico (p INTRODUCTION AND OBJECTIVE: The muscle weakness, strength asymmetries and imbalance between antagonist muscles are risk factors for knee injuries. It is possible that these risk factors increase in soccer players with cerebral palsy (CP due to their pathology and to the sport activity. Therefore, the objective of the present study was to assess the presence of these factors in paralympic athletes with CP from the Brazilian paralympic seven-a-side soccer team. METHODOLOGY: Twenty-one soccer players with CP and spastic hemiplegia were submitted to isokinetic muscle evaluation of their knees flexors and extensors muscles by means of the Cybex 6000 isokinetic dynamometer. The analysis of the muscle strength was performed with a peak torque at 60°/s. The study analyzed the contralateral deficit, the balance between flexor and extensor muscles and compared muscles weakness to the expected values for normal individuals (Neder et al. 1999. The paired t-Student test was used for the statistical analysis with p < 0.05. RESULTS: The peak torque values of the involved flexors (FPT and extensors (EPT knee muscles (FPT = 88.4 ± 26.0 Nm and EPT 155.4 ± 37.2 Nm presented significantly smaller ratios than those of the uninvolved ones (FPT = 116.2 ± 24.8 Nm and EPT = 201.6 ± 38.8 Nm. Only extensor muscles of the involved side were weaker than expected. However, the flexor muscles were weaker than expected in nine out of 21 individuals. The measures of strength of uninvolved knee muscles were not significantly different from the expected values. The average balance between flexors and extensors was within the normal range, although three individuals presented results below the

  14. Experimental knee pain impairs submaximal force steadiness in isometric, eccentric, and concentric muscle actions.

    Science.gov (United States)

    Rice, David A; McNair, Peter J; Lewis, Gwyn N; Mannion, Jamie

    2015-09-12

    Populations with knee joint damage, including arthritis, have noted impairments in the regulation of submaximal muscle force. It is difficult to determine the exact cause of such impairments given the joint pathology and associated neuromuscular adaptations. Experimental pain models that have been used to isolate the effects of pain on muscle force regulation have shown impaired force steadiness during acute pain. However, few studies have examined force regulation during dynamic contractions, and these findings have been inconsistent. The goal of the current study was to examine the effect of experimental knee joint pain on submaximal quadriceps force regulation during isometric and dynamic contractions. The study involved fifteen healthy participants. Participants were seated in an isokinetic dynamometer. Knee extensor force matching tasks were completed in isometric, eccentric, and concentric muscle contraction conditions. The target force was set to 10 % of maximum for each contraction type. Hypertonic saline was then injected into the infrapatella fat pad to generate acute joint pain. The force matching tasks were repeated during pain and once more 5 min after pain had subsided. Hypertonic saline resulted in knee pain with an average peak pain rating of 5.5 ± 2.1 (0-10 scale) that lasted for 18 ± 4 mins. Force steadiness significantly reduced during pain across all three muscle contraction conditions. There was a trend to increased force matching error during pain but this was not significant. Experimental knee pain leads to impaired quadriceps force steadiness during isometric, eccentric, and concentric contractions, providing further evidence that joint pain directly affects motor performance. Given the established relationship between submaximal muscle force steadiness and function, such an effect may be detrimental to the performance of tasks in daily life. In order to restore motor performance in people with painful arthritic conditions of the

  15. Avaliação muscular isocinética da articulação do joelho em atletas das seleções brasileiras infanto e juvenil de voleibol masculino Evaluación muscular isocinetica de la articulación de la rodilla en atletas de las selecciones brasileras infanto y juveniles de voleibol masculino Isokinetic muscle evaluation of the knee joint in athletes of the Under-19 and Under-21 Male Brazilian National Volleyball Team

    Directory of Open Access Journals (Sweden)

    Natalia Franco N. Bittencourt

    2005-12-01

    . El estudio presente puede servir así, como base para las comparaciones de estudios futuros que evalúen la función muscular isocinética en atletas del voleibol.The vertical jump is a basic volleyball practice that demands a high ability to generate strength and work in the muscles involved, mainly in the quadriceps muscle. Due to such demand, muscle imbalances between extensor and flexor muscles may be present, causing an overloading on the muscle-tendinous structures of the knee joint. Thus, the establishment of normal parameters for the muscle function related to that joint in volleyball athletes is necessary. Therefore, the purpose of this study was to assess through isokinetic dynamometry the peak torque, work peak, agonist/antagonist ratio, and fatigue index of the flexor and extensor of the knee among both volleyball athlete population. The isokinetic flexion and extension tests of the knees were performed in the concentric-concentric seat mode at 60 and 300º/sec. velocity in thirty-six athletes (20 under 19-under 21, and 16 under 21. The data allowed to set the parameters for the muscle function of the knee joint among athletes of the 2003 Under 19-Under 21 and Under 21 Brazilian National Team Selection of Male Volleyball. Athletes presented peak torque and work peak values normalized by the body mass to the upper quadriceps to the mean normal values for the athletes and non-athletes populations. Compared to other categories, the under 21 athletes presented significantly higher values for the agonist/antagonist ratio, and peak work ratio of the knee flexors at 60º/sec. velocity. Furthermore, the agonist/antagonist ratio was lower than the reference value expected for both categories, thus characterizing predominance in the extensor musculature over the flexor musculature. The fatigue index was close to what would be expected for the majority of athletes. The present study may be useful as comparison basis for future studies aiming evaluate the isokinetic

  16. Comparison of different passive knee extension torque-angle assessments

    International Nuclear Information System (INIS)

    Freitas, Sandro R; Vaz, João R; Bruno, Paula M; Valamatos, Maria J; Mil-Homens, Pedro

    2013-01-01

    Previous studies have used isokinetic dynamometry to assess joint torques and angles during passive extension of the knee, often without reporting upon methodological errors and reliability outcomes. In addition, the reliability of the techniques used to measure passive knee extension torque-angle and the extent to which reliability may be affected by the position of the subjects is also unclear. Therefore, we conducted an analysis of the intra- and inter-session reliability of two methods of assessing passive knee extension: (A) a 2D kinematic analysis coupled to a custom-made device that enabled the direct measurement of resistance to stretch and (B) an isokinetic dynamometer used in two testing positions (with the non-tested thigh either flexed at 45° or in the neutral position). The intra-class correlation coefficients (ICCs) of torque, the slope of the torque-angle curve, and the parameters of the mathematical model that were fit to the torque-angle data for the above conditions were measured in sixteen healthy male subjects (age: 21.4 ± 2.1 yr; BMI: 22.6 ± 3.3 kg m −2 ; tibial length: 37.4 ± 3.4 cm). The results found were: (1) methods A and B led to distinctly different torque-angle responses; (2) passive torque-angle relationship and stretch tolerance were influenced by the position of the non-tested thigh; and (3) ICCs obtained for torque were higher than for the slope and for the mathematical parameters that were fit to the torque-angle curve. In conclusion, the measurement method that is used and the positioning of subjects can influence the passive knee extension torque-angle outcome. (paper)

  17. Oral L-menthol reduces thermal sensation, increases work-rate and extends time to exhaustion, in the heat at a fixed rating of perceived exertion.

    Science.gov (United States)

    Flood, T R; Waldron, M; Jeffries, O

    2017-07-01

    The study investigated the effect of a non-thermal cooling agent, L-menthol, on exercise at a fixed subjective rating of perceived exertion (RPE) in a hot environment. Eight male participants completed two trials at an exercise intensity between 'hard' and 'very hard', equating to 16 on the RPE scale at ~35 °C. Participants were instructed to continually adjust their power output to maintain an RPE of 16 throughout the exercise trial, stopping once power output had fallen by 30%. In a randomized crossover design, either L-menthol or placebo mouthwash was administered prior to exercise and at 10 min intervals. Power output, [Formula: see text]O 2 , heart rate, core and skin temperature was monitored, alongside thermal sensation and thermal comfort. Isokinetic peak power sprints were conducted prior to and immediately after the fixed RPE trial. Exercise time was greater (23:23 ± 3:36 vs. 21:44 ± 2:32 min; P = 0.049) and average power output increased (173 ± 24 vs. 167 ± 24 W; P = 0.044) in the L-menthol condition. Peak isokinetic sprint power declined from pre-post trial in the L-menthol l (9.0%; P = 0.015) but not in the placebo condition (3.4%; P = 0.275). Thermal sensation was lower in the L-menthol condition (P = 0.036), despite no changes in skin or core temperature (P > 0.05). These results indicate that a non-thermal cooling mouth rinse lowered thermal sensation, resulting in an elevated work rate, which extended exercise time in the heat at a fixed RPE.

  18. High sedentary behavior and compromised physical capabilities in adult smokers despite the suitable level of physical activity in daily life

    Directory of Open Access Journals (Sweden)

    Vinicius Tonon Lauria

    2017-05-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2017v19n1p62   Sedentary behavior may play an important role for health outcomes, regardless of the amount of physical activity in daily life (PADL.We aimed to evaluate and compare sedentary behavior as well as physical capabilities in physically active smokers and non-smokers. Twenty-eight adult smokers and 38 non-smokers free of lung disease were matched for age, sex, body mass index, body composition, cardiovascular risk and moderate-to-vigorous PADL. Participants underwent spirometry, cardiopulmonary exercise test (CPET, six-minute walk test (6MWT, isokinetic dynamometry, and body composition (bioelectrical impedance.Despite the similar amount of moderate-to-vigorous PADL(median, 4.5h/week for smokers and 4.0h/week for non-smokers, smokers spent more time lying (median, 8.2h/week: 95% confidence interval, 5.4 to 19.1 vs. 6.1h/week: 3.7 to 11.2 and in sedentary activities (median, 100h/week: 66 to 129 vs. 78h/week: 55 to 122 compared to non-smokers. Smokers also presented worse spirometry, peak V’O2 and maximum heart rate in the CPET, 6MWT, and isokinetic indices (p<0.05. We observed a strong correlation between the time spent lying and spirometry (r = - 0.730 in smokers. Smoking is related to higher sedentary behavior, despite the suitable PADL. An appropriate PADL did not reduce the deleterious effects of smoking on physical capabilities. Interrupting sedentary behavior may be an appropriate intervention target in smokers for reducing the risk of diseases.

  19. The effect of growth hormone (GH) replacement on muscle strength in patients with GH-deficiency: a meta-analysis.

    LENUS (Irish Health Repository)

    Widdowson, W Matthew

    2012-02-01

    CONTEXT\\/OBJECTIVES: GH replacement increases muscle mass and reduces body fat in growth hormone deficiency (GHD) adults. A recent meta-analysis has demonstrated that this improvement in body composition is associated with improved exercise performance. The current meta-analysis was carried out to determine whether high-quality evidence exists to support a beneficial effect of GH replacement on strength. DESIGN\\/METHODS: An extensive Medline search\\/literature review identified eight studies with utilizable, robust data, involving 231 patients in nine cohorts. Previously unpublished data were sought from authors and obtained in two cases. All studies included were randomized, double-blind, placebo-controlled, of parallel or cross-over design and of an average 6.7 months duration. Information was retrieved in uniform format, with data pertaining to patient numbers, study-design, GH-dose, mean age, IGF-I levels and muscle strength measurements (isometric or isokinetic quadriceps strength) recorded. Data were analysed using a fixed-effects model, utilizing continuous data measured on different scales. A summary effect measure (d(s)) was derived for individual strength variables, whereas an overall summary effect was derived from the sum of all studies incorporating different variables; 95% CIs were calculated from the weighted variances of individual study effects. RESULTS: Analysis revealed no significant improvement, neither when all studies were combined (d(s) = +0.01 +\\/- 0.26) nor when measured individually (isometric quadriceps strength, d(s) = +0.02 +\\/- 0.32 and isokinetic quadriceps strength, d(s) = 0.00 +\\/- 0.45). CONCLUSIONS: Evidence from short-term controlled studies fails to support a benefit on muscle strength of GH replacement in GHD patients, which is likely to occur over a longer time-course, as seen in open-label studies.

  20. Validity and test-retest reliability of a novel simple back extensor muscle strength test.

    Science.gov (United States)

    Harding, Amy T; Weeks, Benjamin Kurt; Horan, Sean A; Little, Andrew; Watson, Steven L; Beck, Belinda Ruth

    2017-01-01

    To develop and determine convergent validity and reliability of a simple and inexpensive clinical test to quantify back extensor muscle strength. Two testing sessions were conducted, 7 days apart. Each session involved three trials of standing maximal isometric back extensor muscle strength using both the novel test and isokinetic dynamometry. Lumbar spine bone mineral density was examined by dual-energy X-ray absorptiometry. Validation was examined with Pearson correlations ( r ). Test-retest reliability was examined with intraclass correlation coefficients and limits of agreement. Pearson correlations and intraclass correlation coefficients are presented with corresponding 95% confidence intervals. Linear regression was used to examine the ability of peak back extensor muscle strength to predict indices of lumbar spine bone mineral density and strength. A total of 52 healthy adults (26 men, 26 women) aged 46.4 ± 20.4 years were recruited from the community. A strong positive relationship was observed between peak back extensor strength from hand-held and isokinetic dynamometry ( r  = 0.824, p  strength test, short- and long-term reliability was excellent (intraclass correlation coefficient = 0.983 (95% confidence interval, 0.971-0.990), p  strength measures with the novel back extensor strength protocol were -6.63 to 7.70 kg, with a mean bias of +0.71 kg. Back extensor strength predicted 11% of variance in lumbar spine bone mineral density ( p  strength ( p  strength is quick, relatively inexpensive, and reliable; demonstrates initial convergent validity in a healthy population; and is associated with bone mass at a clinically important site.

  1. Lower extremity strength, systemic inflammation and all-cause mortality: Application to the "fat but fit" paradigm using cross-sectional and longitudinal designs.

    Science.gov (United States)

    Buckner, Samuel L; Loenneke, Jeremy P; Loprinzi, Paul D

    2015-10-01

    No study has applied the "fat-but-fit" paradigm with respect to muscular strength as an index of fitness, despite muscular strength being independently associated with functional ability and mortality. To examine the relationship between lower extremity muscular strength, C-reactive protein (CRP), and all-cause mortality among normal weight, overweight and obese individuals. Data from the 1999-2002 NHANES were used (N=2740 adults; ≥ 50 years). CRP values were obtained from a blood sample. Lower body isokinetic knee extensor strength (IKES) was assessed using a Kin Kom MP isokinetic dynamometer. Participant data was linked to death certificate data from the National Death Index to ascertain all-cause mortality status. Participants were classified, based on body mass index (BMI) and strength as: normal weight and unfit (fit (≥ 75th IKES percentile); overweight and fit; and obese and fit. Independent of physical activity and other confounders, compared to those who were normal weight and unfit, unfit overweight (β=.14, p=0.009), unfit obese (β=.33, pfit (β=.17, p=0.008) participants, had higher CRP levels. However, there was no difference in CRP levels between normal weight and unfit participants and overweight and fit participants (β=0.04, p=0.35). Compared to normal weight unfit adults, overweight fit (HR=0.28; 95% CI: 0.11-0.70; p=0.008) adults had a lower hazard rate for all-cause mortality. These finding suggest that increased lower body strength, independent of physical activity, may reduce premature all-cause mortality and attenuate systemic inflammation among overweight adults. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Knee strength, power and stair performance of the elderly 5 years after unicompartmental knee arthroplasty.

    Science.gov (United States)

    Li, Yumeng; Kakar, Rumit S; Fu, Yang-Chieh; Mahoney, Ormonde M; Kinsey, Tracy L; Simpson, Kathy J

    2018-04-13

    Unicompartmental knee arthroplasty (UKA) has been shown to demonstrate some satisfactory short-term outcomes. However, to our knowledge, there have been no reports on midterm or long-term knee extensor strength and leg extensor power post-UKA. Therefore, the purposes of this study were: (1) to assess the isokinetic knee extensor strength, leg extensor power and stair performance of elderly participants at 5 years UKA post-operation; (2) to compare the differences in knee extensor strength and leg extensor power between the UKA and contralateral healthy limbs. Nineteen elderly participants (75 ± 5 years) who had a medial or a lateral compartment UKA at 5 years post-operation were recruited. The isokinetic knee extensor strength and leg extensor power were measured. The stair performance was tested on a 4-step stair, and ascent and descent velocities were calculated. The pain level was assessed. The UKA limbs' knee extensor strength and leg extensor power were 1.01 ± 0.39 Nm/kg and 0.98 ± 0.27 W/kg, respectively. The stair ascent and descent velocities were 0.37 ± 0.07 and 0.38 ± 0.11 m/s, respectively. In addition, the UKA limbs exhibited comparable knee strength and leg power relative to the contralateral limbs. In general, the knee extensor strength and leg extensor power exhibited by the UKA limbs at 5 years post-operation may be typical in comparison with the normative data. We suggest that UKA is a satisfactory treatment in regard to the recovery of knee strength, leg power and ability to climb up and down stairs.

  3. SNIFFER: An aerial platform for the plume phase of a nuclear emergency

    Science.gov (United States)

    Castelluccio, D. M.; Cisbani, E.; Frullani, S.

    2012-04-01

    When a nuclear or radiological accident results in a release of a radioactive plume, AGS (Aerial Gamma Spectrometry) systems used in many countries, equipped with passive detectors, can help in giving quantitative assessment on the radiological situation (land surface contamination level) only when the air contamination due to the passage of the travelling plume has become negligible. To overcome this limitation, the Italian Institute of Health has developed and implemented a multi purpose air sampling system based on a fixed wing aircraft, for time-effective, large areas radiological surveillance (to face radiological emergency and to support homeland security). A fixed wing aircraft (Sky Arrow 650) with the front part of the fuselage properly adapted to house the detection equipment has been equipped with a compact air sampling line where the isokinetic sampling is dynamically maintained. Aerosol is collected on a Teflon® filter positioned along the line and hosted on a rotating 4-filters disk. A complex of detectors allows radionuclide identification in the collected aerosol samples. A correlated analysis of these two detectors data allows a quantitative measurement of air as well as ground surface concentration of gamma emitting radioisotopes. Environmental sensors and a GPS receiver support the characterization of the sampling conditions and the temporal and geolocation of the acquired data. Acquisition and control system based on compact electronics and real time software that operate the sampling line actuators, guarantee the dynamical isokinetic condition, and acquire the detectors and sensor data. The system is also equipped with other sampling lines to provide information on the concentration of other chemical pollutants. Operative flights have been carried out in the last years, and performances and results are presented.

  4. Changes in Muscle Strength in U19 Soccer Players During an Annual Training Cycle

    Directory of Open Access Journals (Sweden)

    Lehnert Michal

    2014-10-01

    Full Text Available The aim of the study was to investigate the seasonal variation in isokinetic strength of the knee flexors and extensors, and conventional (H/QCONV and functional (H/QFUNC hamstring to quadriceps strength ratios in highly trained adolescent soccer players. The players (n=11; age 17.8±0.3 were measured at the end of the competitive season (autumn, at the beginning and the end of pre-season (winter and during the sixth week of a new competitive season. Isokinetic peak torque (concentric and eccentric was measured at 60°•s-1 in a sitting position with the hip flexed at 100°. The testing range of motion was set from 10 - 90° of knee flexion. The players performed a set of five maximum repetitions for both the dominant and non-dominant leg. Statistically significant differences (p<0.001 between the four seasonal measurements were noted for peak torque of the dominant leg knee flexors in concentric muscle action only. A post hoc analysis revealed a statistically significant increase in peak torque from the 1st to the 4th measurement (p<0.001; d=0.692 and from the 2nd to the 4th (p<0.01; d=0.564. The differences in the changes of peak torque of the knee flexors and extensors depending on type of muscle action and tendencies found in the H/Q ratios throughout the annual training cycle indicate that strength assessment of the knee flexors and extensors and their balance throughout the annual training cycle could be beneficial for elite male adolescent soccer players both in terms of performance and risk of injury.

  5. Characteristics of upper extremity's muscle strength in Turkish national wheelchair basketball players team.

    Science.gov (United States)

    Akınoğlu, Bihter; Kocahan, Tuğba

    2017-02-01

    The objective of this study was to reveal characteristics of muscle strength of upper extremities of wheelchair (WC) basketball players and to ensure more-specific training program preparation. Isokinetic muscle strength of 12 WC basketball players were assessed by ISOMED 2000 device. The assessment protocol was evaluated at 60°/sec velocity with 5 times repeated force and at 240°/sec with 15 times repeated force. This protocol was carried out individually for shoulder flexion-extension and wrist flexion-extension movements at the right and left extremities. The flexion/extension ratio was determined to be outside of the ratios accepted as normal for primarily shoulder joint and for wrist joint. The extension movement was stronger than flexion movement in the shoulders at both velocities and the flexion movement was stronger than ex-tension movement in the wrist. The repeat times where the peak torque occurred were 2-3 repeats at 60°/sec velocity during flexion and extension movements for the wrist and shoulders, and the peak torque occurred at an average of 5-6 repeats in the shoulders at 240°/sec velocity and it occurred at 3-4 repeats in the wrist. The angles where the peak torque of the shoulder flexion and extension occurred varied between 80°-115° at both velocities, and it varied between 5°-30° angles for the wrist. As this study revealed, determination of muscle strength characteristics of WC athletes and especially using objective isokinetic devices will guide the planning of the appropriate training and exercise programs and preventing sports injuries in long term.

  6. Effects of age and sedentary lifestyle on skeletal muscle NF-kappaB signaling in men.

    Science.gov (United States)

    Buford, Thomas W; Cooke, Matthew B; Manini, Todd M; Leeuwenburgh, Christiaan; Willoughby, Darryn S

    2010-05-01

    Nuclear factor kappa B (NF-kappaB) is a critical signaling molecule of disuse-induced skeletal muscle atrophy. However, few studies have carefully investigated whether similar pathways are modulated with physical activity and age. The present study examined lean mass, maximal force production, and skeletal muscle NF-kappaB signaling in 41 men categorized as sedentary (OS, N = 13, 63.85 +/- 6.59 year), physically active (OA, N = 14, 60.71 +/- 5.54 year), or young and sedentary (YS, N = 14, 21.35 +/- 3.84 year). Muscle tissue from the vastus lateralis was assayed for messenger RNA (mRNA) expression of the beta subunit of IkB kinase (IKKbeta), cytosolic protein content of phosphorylated inhibitor of kappa B alpha (pIKBalpha), and nuclear content of NF-kappaB subunits p50 and p65. When compared with YS, OS demonstrated age-related muscle atrophy and reduced isokinetic knee extension torque. Physical activity in older individuals preserved maximal isokinetic knee extension torque. OS muscle contained 50% more pIKBalpha than OA and 61% more pIKBalpha than YS. Furthermore, nuclear p65 was significantly elevated in OS compared with YS. OS muscle did not differ from either of the other two groups for nuclear p50 or for mRNA expression of IKKbeta. These results indicate that skeletal muscle content of nuclear-bound p65 is elevated by age in humans. The elevation in nuclear-bound p65 appears to be at least partially due to significant increases in pIKBalpha. A sedentary lifestyle appears to play some role in increased IKBalpha; however, further research is needed to identify downstream effects of this increase.

  7. The effect of basketball training on the muscle strength of adults with mental retardation.

    Science.gov (United States)

    Tsimaras, Vasilios K; Samara, Christina A; Kotzamanidou, Marianna C; Bassa, Eleni I; Fotiadou, Eleni G; Kotzamanidis, Christos M

    2009-12-01

    The purpose of this study was to evaluate the effect of basketball training on the muscle strength of adults with mental retardation (MR). Twenty-four adults with and without MR were separated into 3 groups. Eight adults (mean age 25.4 years) with normal IQ constituted the control group (NIQ). Eight adults (mean age 26.5 years) with MR and all participating in a 4-year systematic basketball exercise program constituted the trained group (MR-T), and 8 adults (mean age 25.3 years) with MR exercised occasionally for recreational reasons formed the MR-R group. Parameters measured were isometric and isokinetic concentric and eccentric muscle strength. All subjects performed a leg strength test on a Cybex Norm isokinetic dynamometer. Analysis of variance was used to examine mean differences between the values of the 3 groups. A significance level of 0.05 was used for all tests. The NIQ group showed a statistically significant difference in all measured values compared to the MR groups. The MR-T group presented higher absolute and relative torque scores for both knee extensors and flexors than the MR-R group, whereas the MR-R group presented statistically higher antagonistic activity for both knee extensors and flexors than the MR-T group. In addition, both MR groups presented statistically higher antagonistic activity for both knee extensors and flexors compared to the NIQ group. Data support participation on a systematic and well-designed basketball training program to improve muscle strength levels of adults with MR. Participation in basketball without necessarily focusing on developing specific fitness components may be an effective training strategy for the promotion of strength of adults with MR.

  8. Neuromuscular Changes in Female Collegiate Athletes Resulting From a Plyometric Jump-Training Program.

    Science.gov (United States)

    Wilkerson, Gary B.; Colston, Marisa A.; Short, Nancy I.; Neal, Kristina L.; Hoewischer, Paul E.; Pixley, Jennifer J.

    2004-03-01

    OBJECTIVE: To assess performance changes induced by a 6- week plyometric jump-training program. DESIGN AND SETTING: We used a quasiexperimental design to compare groups formed on the basis of team membership. Testing was conducted in an athletic training research laboratory, both before and after a 6-week period of preseason basketball conditioning. SUBJECTS: Nineteen female collegiate basketball players from a National Collegiate Athletic Association Division I program (8 subjects) and a National Association of Intercollegiate Athletics Division II program (11 subjects) who had no history of anterior cruciate ligament injury and who had no history of any lower extremity injury during the preceding 6 months. MEASUREMENTS: The variables of primary interest were hamstrings and quadriceps isokinetic peak torque. Of secondary interest were 5 variables derived from step-down and lunging maneuvers performed on a computerized forceplate system and 4 variables derived from tracking the position of the body core during performance of a T-pattern agility drill with a computerized infrared tracking system. RESULTS: A significant group x trial interaction was found for hamstrings peak torque at 60 degrees.s(-1) (F(1,17) = 9.16, P =.008.), and the proportion of total variance attributable to the treatment effect produced by the jump-training program was relatively large (eta(2) =.35, omega(2) =.30). None of the other variables demonstrated statistically significant changes. CONCLUSIONS: Our primary results support plyometric jump training as a strategy for improving neuromuscular attributes that are believed to reduce the risk of anterior cruciate ligament injury in female college basketball players. They also provide the basis for reasonable isokinetic strength goals.

  9. Isokinetic torque peak and hamstrings/quadriceps ratios in endurance athletes with anterior cruciate ligament laxity Pico de torque isocinético e relação ísquios-tibiais/quadríceps em atletas de endurance com frouxidão do ligamento cruzado anterior

    Directory of Open Access Journals (Sweden)

    Eliane Magaieski Portes

    2007-01-01

    Full Text Available PURPOSE: To evaluate torque and the hamstring/quadriceps ratio of the knee of athletes with and without anterior cruciate ligament laxity. METHODS: Twenty-eight male athletes, 19 without anterior cruciate ligament laxity and 9 with anterior cruciate ligament laxity, were evaluated with an isokinetic machine model Cybex 770. The peak torque of quadriceps and hamstrings was compared, and the hamstring/quadriceps ratio on the constant angular speed of 60º per second were also compared. RESULTS: In athletes with anterior cruciate ligament laxity, the peak torque values (right and left knees of flexors (120 ± 15 and 116 ± 15 Nm and of extensors (218 ± 36 Nm and 207 ± 26 Nm were not different than those of athletes without laxity (109 ± 21 Nm and 111 ± 22 Nm; 191 ± 5 Nm and 188 ± 35 Nm. The hamstring/quadriceps ratio of athletes with laxity (right: 57 ± 6% and left: 56 ± 8% did not differ from those without anterior cruciate ligament laxity (right: 58 ± 9% and left: 58 ± 7%. CONCLUSIONS: The anterior cruciate ligament laxity of long distances running athletes did not significantly alter the peak torque of flexors and of extensors or the hamstring/quadriceps ratio.OBJETIVO: Avaliar o torque e a relação de forças entre ísquios-tibiais/quadríceps dos joelhos de atletas corredores de longas distâncias com e sem frouxidão do ligamento cruzado anterior. METODOLOGIA: Vinte e oito atletas do gênero masculino, 19 sem frouxidão do ligamento cruzado anterior e 9 com frouxidão do ligamento cruzado anterior foram avaliados com aparelho isocinético modelo Cybex 770. Comparou-se o pico de torque dos quadríceps e dos ísquios-tibiais e a relação ísquios-tibiais/quadríceps na velocidade angular constante de 60º por segundo. Os dados obtidos foram comparados por meio dos testes t de Student e para dados pareados (membros direito e esquerdo e o nível de significância estabelecido foi p < 0,05. RESULTADOS: Nos atletas com frouxidão do

  10. Electromyographic analysis of repeated bouts of eccentric exercise.

    Science.gov (United States)

    McHugh, M P; Connolly, D A; Eston, R G; Gartman, E J; Gleim, G W

    2001-03-01

    The repeated bout effect refers to the protective effect provided by a single bout of eccentric exercise against muscle damage from a similar subsequent bout. The aim of this study was to determine if the repeated bout was associated with an increase in motor unit activation relative to force production, an increased recruitment of slow-twitch motor units or increased motor unit synchronization. Surface electromyographic (EMG) signals were recorded from the hamstring muscles during two bouts of submaximal isokinetic (2.6 rad x s(-1)) eccentric (11 men, 9 women) or concentric (6 men, 4 women) contractions separated by 2 weeks. The EMG per unit torque and median frequency were analysed. The initial bout of eccentric exercise resulted in strength loss, pain and muscle tenderness, while the repeated eccentric bout resulted in a slight increase in strength, no pain and no muscle tenderness (bout x time effects, P exercise. The EMG per unit torque and median frequency were not different between the initial and repeated bouts of eccentric exercise. The EMG per unit torque and median frequency increased during both bouts of eccentric exercise (P < 0.01) but did not change during either concentric bout. In conclusion, there was no evidence that the repeated bout effect was due to a neural adaptation.

  11. Novel mass spectrometric instrument for gaseous and particulate characterization and monitoring. Quarterly report, April 1, 1994--June 30, 1994

    International Nuclear Information System (INIS)

    Coggiola, M.J.

    1994-07-01

    Purpose of the instrument is for real-time (<1 min), ppB analysis of gaseous/particulate pollutants (VOCs, PAHs, heavy metals, transuranics) from DOE waste cleanup. It will consist of an isokinetic sampler, a pressure transition and sampling region for parallel analyses, two small mass spectrometers (one for organic analysis using field ionization, one [ion trap] for particulates using pyrolysis and electron-impact ionization), and a personal computer. A dimethylsilicone membrane will be used for the organic vapors. A forward-backward coincidence method will be used in the laser scattering particle detector. The instrument will be easily transportable to DOE waste sites, such as waste storage tanks

  12. Aging impairs the recovery in mechanical muscle function following 4 days of disuse

    DEFF Research Database (Denmark)

    Hvid, L G; Suetta, C; Nielsen, J H

    2014-01-01

    As aged individuals are frequently exposed to short-term disuse caused by disease or musculoskeletal injury, it is important to understand how short-term disuse and subsequent retraining affect lower limb mechanical muscle function. The purpose of the present study was, therefore, to investigate...... the effect of 4 days of lower limb disuse followed by 7 days of active recovery on mechanical muscle function of the knee extensors in young (24.3±0.9 years, n=11) and old (67.2±1.0 years, n=11) recreationally active healthy males. Slow and moderate dynamic muscle strength were assessed using isokinetic...... to disuse, marked age-related differences (p

  13. Feasibility and efficacy of progressive resistance training and dietary supplements in radiotherapy treated head and neck cancer patients - the DAHANCA 25A study

    DEFF Research Database (Denmark)

    Lønbro, Simon; Dalgas, Ulrik; Primdahl, Hanne

    2013-01-01

    weeks of PRT ± protein and creatine supplementation among HNSCC patients. Secondly, to investigate group changes over time and group differences regarding lean body mass (LBM), muscle strength and functional performance following PRT ± dietary supplementation. Material and methods. Thirty patients were...... supplementation. Before the pre-trial and pre- and post-PRT evaluation of LBM, maximal isometric and isokinetic muscle strength and functional performance were performed. Results. Seventy percent of the patients completed the intervention and the PRT adherence rate was 97%. No significant group differences were...... found in any endpoints. From pre- to post-PRT, LBM increased significantly in the PROCR group by 2.6 ± 2.2 kg (p

  14. Força muscular de atletas de voleibol de 9 a 18 anos através da dinamometria computadorizada Fuerza muscular de atletas de voleibol de 9 a 18 años a través de la dinamometria computarizada Muscular strength of 9-18-year old volleyball athletes through computational dynamometry

    Directory of Open Access Journals (Sweden)

    Patrícia Schneider

    2004-04-01

    Full Text Available O objetivo deste estudo foi descrever e comparar as forças musculares isométrica e isocinética em diferentes graus maturacionais de meninos e meninas atletas de voleibol. Participou do estudo um total de 66 crianças e adolescentes saudáveis, em treinamento esportivo competitivo. Dos 37 meninos, 10 eram pré-púberes (PP, 15 púberes (PU e 12 pós-púberes (PO. Das 29 meninas, 11 eram PP, 13 PU e 5 PO. Foi utilizado um dinamômetro computadorizado (Cybex Norm para medir a força isocinética de flexão do cotovelo (FC e de extensão de joelho (EJ nas velocidades de 60 e 90º.s-1. A força isométrica foi medida nos mesmos exercícios nos ângulos de 60 e 90º (FC, e 45 e 60º (EJ. Utilizou-se a ANOVA para comparações entre os gêneros e graus maturacionais, e o teste post hoc de Tuckey. O nível de significância considerado foi de p El objetivo de este estudio fué describir y comparar las fuerzas musculares isométrica e isocinética en diferentes grados maduracionales de niños y niñas atletas de voleibol. Participó del estudio un total de 66 niños y adolescentes, en tratamiento deportivo competitivo. De los 37 niños, 10 eran pre-púberes (PP, 15 púberes (PU y 12 post-púberes (PO. De las 29 niñas, 11 eran PP, 13 PU e 5 PO. Fué utilizado un dinamómetro computarizado (Cybex Norm para medir la fuerza isocinética de flexión de codo (FC y extensión de rodilla (EJ en las velocidades de 60 y 90º.s-1. La fuerza isométrica fue medida en los mismos ejercicios en los ángulos de 60 y 90º (FC, y 45 y 60º (EJ. Se utilizó la ANOVA para comparaciones entre los géneros y grados maduracionales y el test post hoc de Tuckey. El nivel de significancia considerado fue de p The objective of this work was to describe and to compare the isometric and isokinetic muscular strength at different maturational degree of boys and girls volleyball athletes. 66 healthy children and youth participated in the study in a competitive sportive training

  15. An Ecological Study of Anterior Cruciate Ligament Reconstruction, Part 2: Functional Performance Tests Correlate With Return-to-Sport Outcomes.

    Science.gov (United States)

    McGrath, Timothy M; Waddington, Gordon; Scarvell, Jennie M; Ball, Nick; Creer, Rob; Woods, Kevin; Smith, Damian; Adams, Roger

    2017-02-01

    Additional high-quality prospective studies are needed to better define the objective criteria used in relation to return-to-sport decisions after anterior cruciate ligament (ACL) reconstruction in active populations. To investigate prospectively the relationship between functional performance test results at 24 weeks postoperative and return-to-sport activity (Tegner activity score) at 12 and 24 months, respectively, after synthetic (ligament advanced reinforcement system [LARS]) and autograft (doubled semitendinosus/gracilis [2ST/2GR]) ACL reconstructions. Case series; Level of evidence, 4. A total of 64 patients who underwent ACL reconstruction (32 LARS, 32 2ST/2GR autograft; mean age, 27.9 years; body mass index [BMI], 24.9 kg/m 2 ) were assessed preoperatively and at staged intervals postoperatively up to 24 weeks for isokinetic testing of quadriceps and hamstring average power per repetition at 60 deg/s and 180 deg/s, a battery of hop tests, peak vertical ground-reaction force (vGRF), and time to peak vGRF (in seconds) during a step- and jump-down task onto a force platform and peak speed (m/s) using a global positioning system (GPS unit) during a running task. A cohort of 32 healthy matched participants (mean age, 26.31 years; BMI, 25.7 kg/m 2 ) were also tested to act as reference. Pearson correlation was calculated to assess correlation of each performance measure at 24 weeks postoperative with activity outcomes (Tegner score) at 12 and 24 months. The strongest correlation between physical performance tests and return-to-sport outcomes was observed with peak speed during running. Large correlations were also observed for hamstring isokinetic power and hop test for distance. Moderate correlations were observed for timed hop, peak vGRF during a jump-down task, and quadriceps isokinetic power. No statistical correlations were observed for time to peak vGRF during a step-down and jump-down task as well as peak vGRF during a step-down task. When the performance

  16. Cold modalities with different thermodynamic properties have similar effects on muscular performance and activation.

    Science.gov (United States)

    Vieira, A; Oliveira, A B; Costa, J R; Herrera, E; Salvini, T F

    2013-10-01

    Although tissue cooling is widely used in the treatment of musculoskeletal injuries there is still controversy about its effects on muscular performance. The combination of cooling and exercise justifies the study of this topic. The aim was to compare the effects of ice pack and cold-water immersion on the muscular performance parameters of plantar flexors and muscular activation of the triceps surae. 41 healthy men (mean age: 22.1 years, SD: 2.9) were randomly assigned to cooling with either ice pack (n=20) or cold-water immersion (n=21). Independent variables were cold modality (ice pack or cold-water immersion) and pre- and post-cooling measurement time. Dependent variables were muscular performance (measured during isometric and concentric contractions of plantar flexors) and electromyography parameters of the triceps surae (median frequency and root mean square amplitude). Dependent-samples t-tests were used to compare pre- and post-cooling data and independent-samples t-tests were used to compare the difference (pre- and post-cooling) between groups. Ice pack increased isometric peak torque (mean: 9.00 Nm, P=0.01) and both cold modalities reduced muscular activation in triceps surae (Pimmersion and ice pack reduced peak torque and total work during dynamic isokinetic contraction at both velocities (mean: -11,00 Nm, Pimmersion decrease concentric muscular performance. These results indicate that these cooling methods should be chosen with caution, considering the type of task required during training or rehabilitation. New studies investigating other muscle groups and joints are necessary. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Estimation of Electrically-Evoked Knee Torque from Mechanomyography Using Support Vector Regression

    Directory of Open Access Journals (Sweden)

    Morufu Olusola Ibitoye

    2016-07-01

    Full Text Available The difficulty of real-time muscle force or joint torque estimation during neuromuscular electrical stimulation (NMES in physical therapy and exercise science has motivated recent research interest in torque estimation from other muscle characteristics. This study investigated the accuracy of a computational intelligence technique for estimating NMES-evoked knee extension torque based on the Mechanomyographic signals (MMG of contracting muscles that were recorded from eight healthy males. Simulation of the knee torque was modelled via Support Vector Regression (SVR due to its good generalization ability in related fields. Inputs to the proposed model were MMG amplitude characteristics, the level of electrical stimulation or contraction intensity, and knee angle. Gaussian kernel function, as well as its optimal parameters were identified with the best performance measure and were applied as the SVR kernel function to build an effective knee torque estimation model. To train and test the model, the data were partitioned into training (70% and testing (30% subsets, respectively. The SVR estimation accuracy, based on the coefficient of determination (R2 between the actual and the estimated torque values was up to 94% and 89% during the training and testing cases, with root mean square errors (RMSE of 9.48 and 12.95, respectively. The knee torque estimations obtained using SVR modelling agreed well with the experimental data from an isokinetic dynamometer. These findings support the realization of a closed-loop NMES system for functional tasks using MMG as the feedback signal source and an SVR algorithm for joint torque estimation.

  18. Velocity-specific strength recovery after a second bout of eccentric exercise.

    Science.gov (United States)

    Barss, Trevor S; Magnus, Charlene R A; Clarke, Nick; Lanovaz, Joel L; Chilibeck, Philip D; Kontulainen, Saija A; Arnold, Bart E; Farthing, Jonathan P

    2014-02-01

    A bout of eccentric exercise (ECC) has the protective effect of reducing muscle damage during a subsequent bout of ECC known as the "repeated bout effect" (RBE). The purpose of this study was to determine if the RBE is greater when both bouts of ECC are performed using the same vs. different velocity of contraction. Thirty-one right-handed participants were randomly assigned to perform an initial bout of either fast (3.14 rad·s [180°·s]) or slow (0.52 rad·s [30°·s]) maximal isokinetic ECCs of the elbow flexors. Three weeks later, the participants completed another bout of ECC at the same velocity (n = 16), or at a different velocity (n = 15). Indirect muscle damage markers were measured before, immediately after, and at 24, 48, and 72 hours postexercise. Measures included maximal voluntary isometric contraction (MVC) strength (dynamometer), muscle thickness (MT; ultrasound), delayed onset muscle soreness (DOMS; visual analog scale), biceps and triceps muscle activation amplitude (electromyography), voluntary activation (interpolated twitch), and twitch torque. After the repeated bout, MVC strength recovered faster compared with the same time points after the initial bout for only the same velocity group (p = 0.017), with no differences for all the other variables. Irrespective of velocity, MT and DOMS were reduced after the repeated bout compared with that of the initial bout at 24, 48, and 72 hours with a corresponding increase in TT at 72 hours (p effects contribute to the RBE. The current findings support the idea of multiple mechanisms contributing to the RBE.

  19. The effects of low and moderate doses of caffeine supplementation on upper and lower body maximal voluntary concentric and eccentric muscle force.

    Science.gov (United States)

    Tallis, Jason; Yavuz, Harley C M

    2018-03-01

    Despite the growing quantity of literature exploring the effect of caffeine on muscular strength, there is a dearth of data that directly explores differences in erogenicity between upper and lower body musculature and the dose-response effect. The present study sought to investigate the effects of low and moderate doses of caffeine on the maximal voluntary strength of the elbow flexors and knee extensors. Ten nonspecifically strength-trained, recreationally active participants (aged 21 ± 0.3 years) completed the study. Using a randomised, counterbalanced, and double-blind approach, isokinetic concentric and eccentric strength was measured at 60 and 180°/s following administration of a placebo, 3 mg·kg -1 body mass caffeine, and 6 mg·kg -1 body mass caffeine. There was no effect of caffeine on the maximal voluntary concentric and eccentric strength of the elbow flexors, or the eccentric strength of the knee extensors. Both 3 and 6 mg·kg -1 body mass caffeine caused a significant increase in peak concentric force of the knee extensors at 180°/s. No difference was apparent between the 2 concentrations. Only 6 mg·kg -1 body mass caused an increase in peak concentric force during repeated contractions. The results infer that the effective caffeine concentration to evoke improved muscle performance may be related to muscle mass and contraction type. The present work indicates that a relatively low dose of caffeine treatment may be effective for improving lower body muscular strength, but may have little benefit for the strength of major muscular groups of the upper body.

  20. Comparison of isokinetic peak force and power in adults with partial and total blindness.

    Science.gov (United States)

    Horvat, Michael; Ray, Christopher; Nocera, Joe; Croce, Ron

    2006-08-01

    For many populations the ability to move efficiently is compromised by an impaired muscular functioning. Strength development is necessary to overcome the effects of gravity to maintain posture and generate movement responses for mobility. The strength and power capabilities of individuals with total blindness (n = 12) were compared to those with partial vision (n = 12) to evaluate effects of vision on performance. Results indicate that (1) no significant differences were apparent between total blindness and partial vision, (2) significant sex differences were evident in each group, and (3) better performance was apparent at lower velocities. It was concluded that physical performance in individuals with blindness and partial vision are equally deficient.

  1. Effect of rest interval on strength recovery in young and old women.

    Science.gov (United States)

    Theou, Olga; Gareth, Jones R; Brown, Lee E

    2008-11-01

    This study compares the effects of rest intervals on isokinetic muscle torque recovery between sets of a knee extensor and flexor exercise protocol in physically active younger and older women. Twenty young (22.4 +/- 1.7 years) and 16 older (70.7 +/- 4.3 years) women performed three sets of eight maximum repetitions of knee extension/flexion at 60 degrees x s(-1). The rest interval between sets was 15, 30, and 60 seconds and was randomly assigned across three testing days. No significant interaction of rest by set by age group was observed. There was a significant decline in mean knee extensor torque when 15- and 30-second rest intervals were used between sets, but not when a 60-second rest interval was applied for both the young and the old women. No significant decline for mean knee flexor torque was observed in the older women when a 30-second rest interval was used, whereas a longer 60-second rest interval was required in younger women. Active younger and older women require similar rest intervals between sets of a knee extensor exercise (60 seconds) for complete recovery. However, older women recovered faster (30 seconds) than younger women (60 seconds) between sets of a knee flexor exercise. The exercise-to-rest ratio for knee extensors was similar for young and old women (1:2). Old women required only a 1:1 exercise-to-rest ratio for knee flexor recovery, whereas younger women required a longer 1:2 exercise-to-rest ratio. The results of the present study are specific to isokinetic testing and training and are more applicable in rehabilitation and research settings. Practitioners should consider age and gender when prescribing rest intervals between sets.

  2. Normative Quadriceps and Hamstring Muscle Strength Values for Female, Healthy, Elite Handball and Football Players.

    Science.gov (United States)

    Risberg, May A; Steffen, Kathrin; Nilstad, Agnethe; Myklebust, Grethe; Kristianslund, Eirik; Moltubakk, Marie M; Krosshaug, Tron

    2018-05-23

    Risberg, MA, Steffen, K, Nilstad, A, Myklebust, G, Kristianslund, E, Moltubakk, MM, and Krosshaug, T. Normative quadriceps and hamstring muscle strength values for female, healthy, elite handball and football players. J Strength Cond Res XX(X): 000-000, 2018-This study presents normative values for isokinetic knee extension and flexion muscle strength tests in 350 elite, female, handball (n = 150) and football (n = 200) players. Isokinetic concentric muscle strength tests at 60°·sec were recorded bilaterally using a dynamometer. Peak torque (in Newton meter [N·m]), body mass normalized peak torque (N·m·kg), and hamstring to quadriceps ratio (H:Q ratio) for dominant and nondominant legs were recorded. The female elite players were 20.9 ± 4.0 years, started playing at the elite level at the age of 18.2 ± 2.7 years, with a mean of 9.7 ± 2.2 hours of weekly in-season training. Handball players demonstrated greater quadriceps muscle strength compared with football players (11.0%) (p handball players only (p = 0.012).The H:Q ratio was significantly lower for handball players (0.58) compared with football players (0.60) (p handball and football players can be used to set rehabilitation goals for muscle strength after injury and enable comparison with uninjured legs. Significantly greater quadriceps muscle strength was found for handball players compared with football players, also when normalized to body mass.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

  3. Intrinsic risk factors of noncontact ankle sprains in soccer: a prospective study on 100 professional players.

    Science.gov (United States)

    Fousekis, Konstantinos; Tsepis, Elias; Vagenas, George

    2012-08-01

    Ankle sprain is an extremely common injury in soccer players. Despite extensive research, the intrinsic cause of this injury under noncontact conditions remains unclear. To identify intrinsic risk factors for noncontact ankle sprains in professional soccer players. Cohort study; Level of evidence, 2 One hundred professional soccer players were assessed in the preseason for potential risk factors of noncontact ankle sprains. The assessment included (A) ankle joint asymmetries (right-left) in isokinetic muscle strength, flexibility, proprioception, and stability; (B) somatometric asymmetries; (C) previous injuries; and (D) lateral dominance traits. Noncontact ankle sprains were prospectively recorded and diagnosed for a full competition period (10 months). Seventeen of the players sustained at least 1 noncontact ankle sprain. Logistic regression revealed that players with (A) eccentric isokinetic ankle flexion strength asymmetries (odds ratio [OR] = 8.88; 95% confidence interval [CI], 1.95-40.36, P = .005), (B) increased body mass index (OR = 8.16; 95% CI, 1.42-46.63, P = .018), and (C) increased body weight (OR = 5.72; 95% CI, 1.37-23.95, P = .017 ) each had a significantly higher risk of a noncontact ankle sprain. A trend for younger players (OR = 0.28; 95% CI, 0.061-1.24, P = .092) and for players with ankle laxity asymmetries (OR = 3.38; 95% CI, 0.82-14.00, P = .093) to be at greater risk for ankle sprain was also apparent to the limit of statistical significance (.05 ankle flexors and increased body mass index and body weight raise the propensity for ankle sprains in professional soccer players. Age and asymmetries in ankle laxity are potential factors worth revisiting, as there was an indication for younger players and players with ankle instability to be at higher risk for ankle injury. Proper preseason evaluation may improve prevention strategies for this type of injury in soccer.

  4. SNIFFER: An aerial platform for the plume phase of a nuclear emergency

    Directory of Open Access Journals (Sweden)

    Cisbani E.

    2012-04-01

    Full Text Available When a nuclear or radiological accident results in a release of a radioactive plume, AGS (Aerial Gamma Spectrometry systems used in many countries, equipped with passive detectors, can help in giving quantitative assessment on the radiological situation (land surface contamination level only when the air contamination due to the passage of the travelling plume has become negligible. To overcome this limitation, the Italian Institute of Health has developed and implemented a multi purpose air sampling system based on a fixed wing aircraft, for time-effective, large areas radiological surveillance (to face radiological emergency and to support homeland security. A fixed wing aircraft (Sky Arrow 650 with the front part of the fuselage properly adapted to house the detection equipment has been equipped with a compact air sampling line where the isokinetic sampling is dynamically maintained. Aerosol is collected on a Teflon® filter positioned along the line and hosted on a rotating 4-filters disk. A complex of detectors allows radionuclide identification in the collected aerosol samples. A correlated analysis of these two detectors data allows a quantitative measurement of air as well as ground surface concentration of gamma emitting radioisotopes. Environmental sensors and a GPS receiver support the characterization of the sampling conditions and the temporal and geolocation of the acquired data. Acquisition and control system based on compact electronics and real time software that operate the sampling line actuators, guarantee the dynamical isokinetic condition, and acquire the detectors and sensor data. The system is also equipped with other sampling lines to provide information on the concentration of other chemical pollutants. Operative flights have been carried out in the last years, and performances and results are presented.

  5. Calf-raise senior: a new test for assessment of plantar flexor muscle strength in older adults: protocol, validity, and reliability.

    Science.gov (United States)

    André, Helô-Isa; Carnide, Filomena; Borja, Edgar; Ramalho, Fátima; Santos-Rocha, Rita; Veloso, António P

    2016-01-01

    This study aimed to develop a new field test protocol with a standardized measurement of strength and power in plantar flexor muscles targeted to functionally independent older adults, the calf-raise senior (CRS) test, and also evaluate its reliability and validity. Forty-one subjects aged 65 years and older of both sexes participated in five different cross-sectional studies: 1) pilot (n=12); 2) inter- and intrarater agreement (n=12); 3) construct (n=41); 4) criterion validity (n=33); and 5) test-retest reliability (n=41). Different motion parameters were compared in order to define a specifically designed protocol for seniors. Two raters evaluated each participant twice, and the results of the same individual were compared between raters and participants to assess the interrater and intrarater agreement. The validity and reliability studies involved three testing sessions that lasted 2 weeks, including a battery of functional fitness tests, CRS test in two occasions, accelerometry, and strength assessments in an isokinetic dynamometer. The CRS test presented an excellent test-retest reliability (intraclass correlation coefficient [ICC] =0.90, standard error of measurement =2.0) and interrater reliability (ICC =0.93-0.96), as well as a good intrarater agreement (ICC =0.79-0.84). Participants with better results in the CRS test were younger and presented higher levels of physical activity and functional fitness. A significant association between test results and all strength parameters (isometric, r =0.87, r 2 =0.75; isokinetic, r =0.86, r 2 =0.74; and rate of force development, r =0.77, r 2 =0.59) was shown. This study was successful in demonstrating that the CRS test can meet the scientific criteria of validity and reliability. The test can be a good indicator of ankle strength in older adults and proved to discriminate significantly between individuals with improved functionality and levels of physical activity.

  6. Mechanical behaviour of hamstring muscles in low-back pain patients and control subjects.

    Science.gov (United States)

    Tafazzoli, F; Lamontagne, M

    1996-01-01

    The purpose of this study was to measure and compare the passive elastic moment, the stiffness and the damping coefficient of the hip joint, as functions of the hip and knee joint angles in men with and without low-back pain. Two conventional tests, the straight-leg-raising test and the trunk forward flexion, were also performed and compared between these subjects. The passive elastic moment was measured using an isokinetic device in the passive mode. This device raised the lower limb from the horizontal position to the straight-leg-raising angle at a slow and constant angular velocity. A custom-made splint connected with the lever arm of the isokinetic device maintained the knee in extension and the ankle in the neutral position. The damping coefficient of the hip joint was measured for 0, 15, 45, 60, 75 and 90% of straight leg raising angle of each subject, using the suspension method based on small oscillation theory. To ensure that muscles were inactive during the passive hip moment tests, muscle activity was monitored with surface EMG. The stiffness was computed as the ratio of the change in passive elastic moment to the change in the hip angle. The passive elastic moment, the stiffness and the normalized trunk flexion were significantly different between the two groups respectively. There was, however, no difference between the two groups in the results of straight-leg-raise and damping coefficient of the hip. The passive elastic moment was a nonlinear function of the hip flexion angle and showed large intersubject differences, especially as the joint limit was approached. The damping coefficient was a polynomial function of the hip flexion angle. The measured variables were analysed using a discriminant function and it was shown that the two groups were clearly discriminable in a meaningful manner.

  7. An investigation of rugby scrimmaging posture and individual maximum pushing force.

    Science.gov (United States)

    Wu, Wen-Lan; Chang, Jyh-Jong; Wu, Jia-Hroung; Guo, Lan-Yuen

    2007-02-01

    Although rugby is a popular contact sport and the isokinetic muscle torque assessment has recently found widespread application in the field of sports medicine, little research has examined the factors associated with the performance of game-specific skills directly by using the isokinetic-type rugby scrimmaging machine. This study is designed to (a) measure and observe the differences in the maximum individual pushing forward force produced by scrimmaging in different body postures (3 body heights x 2 foot positions) with a self-developed rugby scrimmaging machine and (b) observe the variations in hip, knee, and ankle angles at different body postures and explore the relationship between these angle values and the individual maximum pushing force. Ten national rugby players were invited to participate in the examination. The experimental equipment included a self-developed rugby scrimmaging machine and a 3-dimensional motion analysis system. Our results showed that the foot positions (parallel and nonparallel foot positions) do not affect the maximum pushing force; however, the maximum pushing force was significantly lower in posture I (36% body height) than in posture II (38%) and posture III (40%). The maximum forward force in posture III (40% body height) was also slightly greater than for the scrum in posture II (38% body height). In addition, it was determined that hip, knee, and ankle angles under parallel feet positioning are factors that are closely negatively related in terms of affecting maximum pushing force in scrimmaging. In cross-feet postures, there was a positive correlation between individual forward force and hip angle of the rear leg. From our results, we can conclude that if the player stands in an appropriate starting position at the early stage of scrimmaging, it will benefit the forward force production.

  8. Clinical and functional outcome of anterior cruciate ligament reconstruction in the recreational athlete over the age of 35.

    Science.gov (United States)

    Novak, P J; Bach, B R; Hager, C A

    1996-01-01

    This study examined the functional, objective, and subjective outcome of anterior cruciate ligament (ACL) reconstruction in recreational athletes > or = 35 years after a minimum of 2 years of follow-up. Patients > or = 35 years who underwent ACL reconstruction by a single surgeon were identified from our surgical database. Nineteen knees in 18 (62% follow-up) patients were available for review by an independent examiner. The patients underwent physical examination, radiographs, functional testing, isokinetic strength testing, and instrumented ligament arthrometer testing. All were seen at a minimum of 2 years of follow-up. The average age was 40 years. Five of 19 underwent reconstruction less than 1 month after injury, and the remainder underwent reconstruction for chronic injuries. All patients preoperatively had at least a grade 2 Lachman and a positive pivot shift noted on physical examination. After a minimum of 2 years of follow-up, 17 of 18 patients had a stable knee on objective testing, including a negative Lachman and pivot shift. Seventeen patients (94%) had 3 cm prone heel height difference, and all patients had > 125 degrees of flexion. Mean thigh circumference difference was 0.5 cm. Isokinetic testing demonstrated a mean 11%, 7%, and 4% quadriceps asymmetry at 60 degrees, 180 degrees, and 240 degrees/second, respectively. However, functional testing revealed only a mean 6% asymmetry on vertical jump, single leg hop, and timed 6 meter hop. Seventeen of 18 patients were satisfied with their results. The mean postoperative Lysholm Rating Scale score was 93. The mean Noyes Sports Activity Scale score was 86, improved from 31 preoperatively. Thirteen of 18 returned to their preinjury level of sports performance. These results indicate that ACL reconstruction in patients over the age of 35 has functional, objective, and subjective results comparable to those of a younger patient population.

  9. Relationship between body composition, leg strength, anaerobic power, and on-ice skating performance in division I men's hockey athletes.

    Science.gov (United States)

    Potteiger, Jeffrey A; Smith, Dean L; Maier, Mark L; Foster, Timothy S

    2010-07-01

    The purpose of this study was to examine relationships between laboratory tests and on-ice skating performance in division I men's hockey athletes. Twenty-one men (age 20.7 +/- 1.6 years) were assessed for body composition, isokinetic force production in the quadriceps and hamstring muscles, and anaerobic muscle power via the Wingate 30-second cycle ergometer test. Air displacement plethysmography was used to determine % body fat (%FAT), fat-free mass (FFM), and fat mass. Peak torque and total work during 10 maximal effort repetitions at 120 degrees .s were measured during concentric muscle actions using an isokinetic dynamometer. Muscle power was measured using a Monark cycle ergometer with resistance set at 7.5% of body mass. On-ice skating performance was measured during 6 timed 89-m sprints with subjects wearing full hockey equipment. First length skate (FLS) was 54 m, and total length skate (TLS) was 89 m with fastest and average skating times used in the analysis. Correlation coefficients were used to determine relationships between laboratory testing and on-ice performance. Subjects had a body mass of 88.8 +/- 7.8 kg and %FAT of 11.9 +/- 4.6. First length skate-Average and TLS-Average skating times were moderately correlated to %FAT ([r = 0.53; p = 0.013] and [r = 0.57; p = 0.007]) such that a greater %FAT was related to slower skating speeds. First length skate-Fastest was correlated to Wingate percent fatigue index (r = -0.48; p = 0.027) and FLS-Average was correlated to Wingate peak power per kilogram body mass (r = -0.43; p = 0.05). Laboratory testing of select variables can predict skating performance in ice hockey athletes. This information can be used to develop targeted and effective strength and conditioning programs that will improve on-ice skating speed.

  10. Strength asymmetry of the shoulders in elite volleyball players.

    Science.gov (United States)

    Hadzic, Vedran; Sattler, Tine; Veselko, Matjaž; Markovic, Goran; Dervisevic, Edvin

    2014-01-01

    Volleyball players are reported to have shoulder strength imbalances. Previous authors have primarily investigated small samples of male players at a single skill level, without considering playing position, and with inconsistent findings. To evaluate shoulder strength asymmetry and a history of shoulder injury in a large sample of professional volleyball players of both sexes across different playing positions and skill levels. Descriptive laboratory study. A sample of 183 volleyball players (99 men, 84 women). We assessed shoulder internal-rotator and external-rotator concentric strength at 60°/s using an isokinetic dynamometer and dominant-nondominant differences in shoulder strength and strength ratios using repeated-measures analyses of variance. Peak torque was normalized for body mass and external-rotation/internal-rotation concentric strength. Internal-rotation strength was asymmetric in favor of the dominant side in both sexes, regardless of previous shoulder injury status. Male volleyball players had a lower shoulder strength ratio on the dominant side, regardless of previous shoulder injury status. However, this finding was valid only when hand dominance was taken into account. Female volleyball players playing at a higher level (ie, first versus second division) were 3.43 times more likely to have an abnormal strength ratio. Playing position was not associated with an abnormal shoulder strength ratio or strength asymmetry. In male volleyball players, the external-rotation/internal-rotation strength ratio of the dominant shoulder was lower, regardless of playing position, skill level, or a previous shoulder injury. In female players, the ratio was less only in those at a higher skill level. Although speculative, these findings generally suggest that female volleyball players could have a lower risk of developing shoulder-related problems than male volleyball players. Isokinetic shoulder testing may reveal important information about the possible risk

  11. Effects of Age and Sedentary Lifestyle on Skeletal Muscle NF-κB Signaling in Men

    Science.gov (United States)

    Buford, Thomas W.; Cooke, Matthew B.; Manini, Todd M.; Leeuwenburgh, Christiaan

    2010-01-01

    Background. Nuclear factor kappa B (NF-κB) is a critical signaling molecule of disuse-induced skeletal muscle atrophy. However, few studies have carefully investigated whether similar pathways are modulated with physical activity and age. Methods. The present study examined lean mass, maximal force production, and skeletal muscle NF-κB signaling in 41 men categorized as sedentary (OS, N = 13, 63.85 ± 6.59 year), physically active (OA, N = 14, 60.71 ± 5.54 year), or young and sedentary (YS, N = 14, 21.35 ± 3.84 year). Muscle tissue from the vastus lateralis was assayed for messenger RNA (mRNA) expression of the β subunit of IkB kinase (IKKβ), cytosolic protein content of phosphorylated inhibitor of kappa B alpha (pIKBα), and nuclear content of NF-κB subunits p50 and p65. Results. When compared with YS, OS demonstrated age-related muscle atrophy and reduced isokinetic knee extension torque. Physical activity in older individuals preserved maximal isokinetic knee extension torque. OS muscle contained 50% more pIKBα than OA and 61% more pIKBα than YS. Furthermore, nuclear p65 was significantly elevated in OS compared with YS. OS muscle did not differ from either of the other two groups for nuclear p50 or for mRNA expression of IKKβ. Conclusions. These results indicate that skeletal muscle content of nuclear-bound p65 is elevated by age in humans. The elevation in nuclear-bound p65 appears to be at least partially due to significant increases in pIKBα. A sedentary lifestyle appears to play some role in increased IKBα; however, further research is needed to identify downstream effects of this increase. PMID:20045871

  12. Generation of entrained droplets from an imitated disturbance wave and their deposition on the wall

    International Nuclear Information System (INIS)

    Fukano, T.; Inatomi, T.; Matsuzawa, Y.; Yoshida, T.; Uchimichi, N.

    2003-01-01

    In the present experiment, an isokinetic sampling probe technique was used for the measurement of the local droplet flow rate generated from an imitated disturbance wave, which was constructed by injecting liquid through a slit mounted on the bottom wall of a horizontal rectangular duct. The experimental data on the distribution of entrained droplets and their deposition on the duct wall are presented. As a result, it is clarified that the droplet generation is periodic and the distribution of the droplet flow rate is not uniform in both axial and height directions. And accordingly the droplet flow is fundamentally unsteady. Furthermore, the correlation of the entrainment fraction proposed by Paleev-Filippovich is superior to that by others. (orig.)

  13. Investigation Of Wrist Flexor/Extensor Muscle Strength Following Arthroscopic Surgical Treatment Of Lateral Epicondylitis

    Directory of Open Access Journals (Sweden)

    Mustafa Onur SERBEST

    2016-03-01

    Full Text Available Objective: Lateral epicondylitis is a common disease of elbow joint. Repetitive wrist activities and activities that requires strength are risk factors. Wrist extensor muscle strength are decreased in patients with lateral epicondylitis. Materials and Methods: Eight patients with a diagnosis of lateral epicondylitis enrolled to study. Wrist flexor and extensor muscle strength of patients who were completed one year after surgery were measured by isokinetic dynamometer. Results: There were no statistically significant differences between the flexor and extensor muscle strength of the patients (p>0.05. Conclusion: In this study, arthroscopic extensor carpi radialis brevis tendon release in lateral epicondylitis has shown no negative effect on flexor and extensor wrist muscle stregth.

  14. [Electrical acupoint stimulation increases athletes' rapid strength].

    Science.gov (United States)

    Yang, Hua-yuan; Liu, Tang-yi; Kuai, Le; Gao, Ming

    2006-05-01

    To search for a stimulation method for increasing athletes' performance. One hundred and fifty athletes were randomly divided into a trial group and a control group, 75 athletes in each group. Acupoints were stimulated with audio frequency pulse modulated wave and multi-blind method were used to investigate effects of the electric stimulation of acupoints on 30-meter running, standing long jumping and Cybex isokinetic testing index. The acupoint electric stimulation method could significantly increase athlete's performance (P < 0.05), and the biomechanical indexes, maximal peak moment of force (P < 0.05), force moment accelerating energy (P < 0.05) and average power (P < 0.05). Electrical acupoint stimulation can enhance athlete's rapid strength.

  15. Isolated Rupture of the Teres Major Muscle When Water Skiing: A Case Report and Literature Review

    Directory of Open Access Journals (Sweden)

    Julien Cousin

    2018-01-01

    Full Text Available Isolated lesions to the teres major muscle are rare. They generally occur in patients participating in sports such as baseball, tennis, or boxing. We report the case of a sports patient who suffered an isolated injury to the teres major while water skiing. The clinical presentation was confirmed by MRI. Conservative treatment was chosen and consisted of brief analgesic immobilization, followed by rehabilitative treatment. The rapid recovery of this patient with normal isokinetic strength evaluation at 6 months was interesting for objectifying full muscle recovery. Our results and the data from the literature suggest that functional rather than surgical treatment is preferable in isolated lesions to the teres major muscle.

  16. Biomechanical Analysis of Abdominal Injury in Tennis Serves. A Case Report

    Directory of Open Access Journals (Sweden)

    François Tubez, Bénédicte Forthomme, Jean-Louis Croisier, Caroline Cordonnier, Olivier Brüls, Vincent Denoël, Gilles Berwart, Maurice Joris, Stéphanie Grosdent, Cédric Schwartz

    2015-06-01

    Full Text Available The serve is an important stroke in any high level tennis game. A well-mastered serve is a substantial advantage for players. However, because of its repeatability and its intensity, this stroke is potentially deleterious for upper limbs, lower limbs and trunk. The trunk is a vital link in the production and transfer of energy from the lower limbs to the upper limbs; therefore, kinematic disorder could be a potential source of risk for trunk injury in tennis. This research studies the case of a professional tennis player who has suffered from a medical tear on the left rectus abdominis muscle after tennis serve. The goal of the study is to understand whether the injury could be explained by an inappropriate technique. For this purpose, we analyzed in three dimensions the kinematic and kinetic aspects of the serve. We also performed isokinetic tests of the player’s knees. We then compared the player to five other professional players as reference. We observed a possible deficit of energy transfer because of an important anterior pelvis tilt. Some compensation made by the player during the serve could be a possible higher abdominal contraction and a larger shoulder external rotation. These particularities could induce an abdominal overwork that could explain the first injury and may provoke further injuries.

  17. The relationship between muscle strength, anaerobic performance, agility, sprint ability and vertical jump performance in professional basketball players.

    Science.gov (United States)

    Alemdaroğlu, Utku

    2012-03-01

    The purpose of this study was to investigate the relationship between isokinetic knee strength, anaerobic performance, sprinting ability, agility and vertical jump performance in first division basketball players. Twelve male first division basketball players participated in this study. The mean age was 25.1 ± 1.7 yrs; mean body height 194.8 ± 5.7 cm; mean body mass 92.3± 9.8 kg; mean PBF 10.1± 5.1; and mean VO2max 50.55 ± 6.7 ml/kg/min Quadriceps and hamstrings were measured at 60° and 180°/s, anaerobic performance was evaluated using the Wingate anaerobic power test, sprint ability was determined by single sprint performance (10-30 m), jump performance was evaluated by countermovement (CMJ) and squat jump (SJ) tests and agility performance was measured using the T drill agility test. Quadriceps strength was significantly correlated with peak power at all contraction velocities. However, for mean power, significant correlation was only found between the 60° left and 180° right knee quadriceps measurements. No measure of strength was significantly related to the measurements from/results of field tests. Moreover, strong relations were found between the performance of athletes in different field tests (p< 0.05). The use of correlation analysis is the limitation of the this study.

  18. Chronic pain and difficulty in relaxing postural muscles in patients with fibromyalgia and chronic whiplash associated disorders.

    Science.gov (United States)

    Elert, J; Kendall, S A; Larsson, B; Månsson, B; Gerdle, B

    2001-06-01

    To investigate if muscle tension according to the surface electromyogram (EMG) of the shoulder flexors is increased in consecutive patients with fibromyalgia (FM) or chronic whiplash associated disorders (WAD). A total of 59 consecutive patients with FM (n = 36) or chronic WAD (n = 23) performed 100 maximal isokinetic contractions combined with surface electromyography of the trapezius and infraspinatus. A randomized group of pain-free female (n = 27) subjects served as control group. Peak torque initially (Pti) and absolute and relative peak torque at endurance level (PTe, PTer) were registered as output variables, together with the EMG level of unnecessary muscle tension, i.e., the signal amplitude ratio (SAR). The patient groups had a higher level of unnecessary tension initially and at the endurance level. The patients had lower absolute output (PTi and PTe), but the relative levels (PTer) did not differ comparing all 3 groups. Subjects with FM had significantly higher body mass index (BMI) than the other groups. BMI did not influence the SAR but correlated positively with PTi. The results confirmed earlier findings that groups of patients with chronic pain have increased muscle tension and decreased output during dynamic activity compared to pain-free controls. However, the results indicated there is heterogeneity within groups of patients with the same chronic pain disorder and that not all patients with chronic pain have increased muscle tension.

  19. Peak torque and rate of torque development influence on repeated maximal exercise performance: contractile and neural contributions.

    Science.gov (United States)

    Morel, Baptiste; Rouffet, David M; Saboul, Damien; Rota, Samuel; Clémençon, Michel; Hautier, Christophe A

    2015-01-01

    Rapid force production is critical to improve performance and prevent injuries. However, changes in rate of force/torque development caused by the repetition of maximal contractions have received little attention. The aim of this study was to determine the relative influence of rate of torque development (RTD) and peak torque (T(peak)) on the overall performance (i.e. mean torque, T(mean)) decrease during repeated maximal contractions and to investigate the contribution of contractile and neural mechanisms to the alteration of the various mechanical variables. Eleven well-trained men performed 20 sets of 6-s isokinetic maximal knee extensions at 240° · s(-1), beginning every 30 seconds. RTD, T(peak) and T(mean) as well as the Rate of EMG Rise (RER), peak EMG (EMG(peak)) and mean EMG (EMG(mean)) of the vastus lateralis were monitored for each contraction. A wavelet transform was also performed on raw EMG signal for instant mean frequency (if(mean)) calculation. A neuromuscular testing procedure was carried out before and immediately after the fatiguing protocol including evoked RTD (eRTD) and maximal evoked torque (eT(peak)) induced by high frequency doublet (100 Hz). T(mean) decrease was correlated to RTD and T(peak) decrease (R(²) = 0.62; p<0.001; respectively β=0.62 and β=0.19). RER, eRTD and initial if(mean) (0-225 ms) decreased after 20 sets (respectively -21.1 ± 14.1, -25 ± 13%, and ~20%). RTD decrease was correlated to RER decrease (R(²) = 0.36; p<0.05). The eT(peak) decreased significantly after 20 sets (24 ± 5%; p<0.05) contrary to EMG(peak) (-3.2 ± 19.5 %; p=0.71). Our results show that reductions of RTD explained part of the alterations of the overall performance during repeated moderate velocity maximal exercise. The reductions of RTD were associated to an impairment of the ability of the central nervous system to maximally activate the muscle in the first milliseconds of the contraction.

  20. Contract theory and EU Contract Law

    OpenAIRE

    Hesselink, M.W.; Twigg-Flesner, C.

    2016-01-01

    This paper explores the relationship between contract theory and European contract law. In particular, it confronts the leading contract law theories with the main characteristics of EU contract law. The conclusion is that the two do not match well. In particular, monist normative contract theories are largely irreconcilable with the contract law of the EU. The paper further addresses the main implications of this mismatch, both for contract theory and for EU contract law. It suggests that in...

  1. Sampling and characterization of aerosols formed in the atmospheric hydrolysis of UF6

    International Nuclear Information System (INIS)

    Bostick, W.D.; McCulla, W.H.; Pickrell, P.W.; Branam, D.A.

    1983-01-01

    When gaseous UF 6 is released into the atmosphere, it rapidly reacts with ambient moisture to form an aerosol of uranyl fluoride and HF. As part of our Safety Analysis program, we have performed several experimental releases of UF 6 (from natural uranium) in contained volumes in order to investigate techniques for sampling and characterizing the aerosol materials. The aggregrate particle morphology and size distribution have been found to be dependent upon several conditions, including the relative humidity at the time of the release and the elapse time after the release. Aerosol composition and settling rate have been investigated using isokinetic samplers for the separate collection of UO 2 F 2 and HF, and via laser spectroscopic remote sensing (Mie scatter and infrared spectroscopy). 8 references

  2. Changes in muscle strength in patients with statin myalgia.

    Science.gov (United States)

    Panza, Gregory A; Taylor, Beth A; Roman, William; Thompson, Paul D

    2014-10-15

    Statins can produce myalgia or muscle pain, which may affect medication adherence. We measured the effects of statins on muscle strength in patients with previous statin myalgia. Leg isokinetic extension average power at 60° per second (-8.8 ± 10.5N-M, p = 0.02) and average peak torque at 60° per second (-14.0 ± 19.7N-M, p = 0.04) decreased slightly with statin use, but 8 of 10 other variables for leg strength did not change (all p >0.13). Handgrip, muscle pain, respiratory exchange ratio, and daily activity also did not change (all p >0.09). In conclusion, statin myalgia is not associated with reduced muscle strength or muscle performance. Published by Elsevier Inc.

  3. Effects of strength and neuromuscular training on functional performance in athletes after partial medial meniscectomy.

    Science.gov (United States)

    Zhang, Xiaohui; Hu, Min; Lou, Zhen; Liao, Bagen

    2017-02-01

    The aims of this study were to determine an effective knee function rehabilitation program for athletes undergoing partial medial meniscectomy. Participants were randomly assigned to neuromuscular training (NT) or strength training (ST) group and subjected to functional assessments before surgery and again at 4, and 8 weeks post hoc . Functional knee assessment, such as Lysholm knee scoring, star excursion balance, and BTE PrimusRS isokinetic performance tests were evaluated in each group. All postoperational symptoms were significantly improved after 4 and 8 weeks of NT and ST. Both NT and ST programs showed effective knee function recovery seen as an increase in muscular strength and endurance. However, the NT program showed the most significant functional improvement of dynamic balance and coordination.

  4. Contract theory and EU Contract Law

    NARCIS (Netherlands)

    Hesselink, M.W.; Twigg-Flesner, C.

    2016-01-01

    This paper explores the relationship between contract theory and European contract law. In particular, it confronts the leading contract law theories with the main characteristics of EU contract law. The conclusion is that the two do not match well. In particular, monist normative contract theories

  5. Types of contracts and contracting procedures

    International Nuclear Information System (INIS)

    Zijl, N.A. van

    1977-01-01

    Contracting for a nuclear power plant can be carried out in many different ways, from a bilateral agreement between two countries to an international open bidding competition. Also the kind of contracts (turnkey, split-package or multi-contract type) are discussed with their pros and cons as well as the contracting procedures which can be followed to come to the conclusion of a contract. (orig.) [de

  6. Desempenho do membro não-acometido em pacientes com reconstrução do ligamento cruzado anterior Performance of uninjured lower limb after anterior cruciate ligament reconstruction

    Directory of Open Access Journals (Sweden)

    Maria Isabel de Noronha Neta

    2010-09-01

    had ACL reconstruction, and 22 control subjects were assessed as to knee flexor and extensor torque during concentric isokinetic contraction at 60o/s with an isokinetic dynamometer, mean speed of centre of pressure swing during single-limb stance, and submitted to two hop tests to assess functional performance. Results showed no significant differences between uninjured side and healthy subjects lower limbs at all assessed variables (p>0.05. These findings suggest that the uninjured limb may be safely used as reference in studies to assess post-ACL patients.

  7. Effect of Oral Beta-Hydroxy-Beta-Methylbutyrate (HMB Supplementation on Physical Performance in Healthy Old Women Over 65 Years: An Open Label Randomized Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Linda Berton

    Full Text Available Although older people are particularly liable to sarcopenia, limited research is available on beta-hydroxy-beta-methylbutyrate (HMB supplementation in this population, particularly in healthy subjects. In this parallel-group, randomized, controlled, open-label trial, we aimed to evaluate whether an oral supplement containing 1.5 g of calcium HMB for 8 weeks could improve physical performance and muscle strength parameters in a group of community-dwelling healthy older women. Eighty healthy women attending a twice-weekly mild fitness program were divided into two equal groups of 40, and 32 of the treated women and 33 control completed the study. We considered a change in the Short Physical Performance Battery (SPPB score as the primary outcome and changes in the peak torque (PT isometric and isokinetic strength of the lower limbs, 6-minute walking test (6MWT, handgrip strength and endurance as secondary outcomes. Body composition was assessed with dual-energy X-ray absorptiometry (DXA and peripheral quantitative computerized tomography (pQCT. The mean difference between the two groups on pre-post change were finally calculated (delta for each outcome. After 8 weeks, there were no significant differences between the groups’ SPPB, handgrip strength or DXA parameters. The group treated with HMB scored significantly better than the control group for PT isokinetic flexion (delta = 1.56±1.56 Nm; p = 0.03 and extension (delta = 3.32±2.61 Nm; p = 0.03, PT isometric strength (delta = 9.74±3.90 Nm; p = 0.02, 6MWT (delta = 7.67±8.29 m; p = 0.04, handgrip endurance (delta = 21.41±16.28 s; p = 0.02, and muscle density assessed with pQCT. No serious adverse effects were reported in either group. In conclusion, a nutritional supplement containing 1.5 g of calcium HMB for 8 weeks in healthy elderly women had no significant effects on SPPB, but did significantly improve several muscle strength and physical performance parameters.ClinicalTrials.gov NCT

  8. Validity and reliability of an instrumented leg-extension machine for measuring isometric muscle strength of the knee extensors.

    Science.gov (United States)

    Ruschel, Caroline; Haupenthal, Alessandro; Jacomel, Gabriel Fernandes; Fontana, Heiliane de Brito; Santos, Daniela Pacheco dos; Scoz, Robson Dias; Roesler, Helio

    2015-05-20

    Isometric muscle strength of knee extensors has been assessed for estimating performance, evaluating progress during physical training, and investigating the relationship between isometric and dynamic/functional performance. To assess the validity and reliability of an adapted leg-extension machine for measuring isometric knee extensor force. Validity (concurrent approach) and reliability (test and test-retest approach) study. University laboratory. 70 healthy men and women aged between 20 and 30 y (39 in the validity study and 31 in the reliability study). Intraclass correlation coefficient (ICC) values calculated for the maximum voluntary isometric torque of knee extensors at 30°, 60°, and 90°, measured with the prototype and with an isokinetic dynamometer (ICC2,1, validity study) and measured with the prototype in test and retest sessions, scheduled from 48 h to 72 h apart (ICC1,1, reliability study). In the validity analysis, the prototype showed good agreement for measurements at 30° (ICC2,1 = .75, SEM = 18.2 Nm) and excellent agreement for measurements at 60° (ICC2,1 = .93, SEM = 9.6 Nm) and at 90° (ICC2,1 = .94, SEM = 8.9 Nm). Regarding the reliability analysis, between-days' ICC1,1 were good to excellent, ranging from .88 to .93. Standard error of measurement and minimal detectable difference based on test-retest ranged from 11.7 Nm to 18.1 Nm and 32.5 Nm to 50.1 Nm, respectively, for the 3 analyzed knee angles. The analysis of validity and repeatability of the prototype for measuring isometric muscle strength has shown to be good or excellent, depending on the knee joint angle analyzed. The new instrument, which presents a relative low cost and easiness of transportation when compared with an isokinetic dynamometer, is valid and provides consistent data concerning isometric strength of knee extensors and, for this reason, can be used for practical, clinical, and research purposes.

  9. Effect of Oral Beta-Hydroxy-Beta-Methylbutyrate (HMB) Supplementation on Physical Performance in Healthy Old Women Over 65 Years: An Open Label Randomized Controlled Trial.

    Science.gov (United States)

    Berton, Linda; Bano, Giulia; Carraro, Sara; Veronese, Nicola; Pizzato, Simona; Bolzetta, Francesco; De Rui, Marina; Valmorbida, Elena; De Ronch, Irene; Perissinotto, Egle; Coin, Alessandra; Manzato, Enzo; Sergi, Giuseppe

    2015-01-01

    Although older people are particularly liable to sarcopenia, limited research is available on beta-hydroxy-beta-methylbutyrate (HMB) supplementation in this population, particularly in healthy subjects. In this parallel-group, randomized, controlled, open-label trial, we aimed to evaluate whether an oral supplement containing 1.5 g of calcium HMB for 8 weeks could improve physical performance and muscle strength parameters in a group of community-dwelling healthy older women. Eighty healthy women attending a twice-weekly mild fitness program were divided into two equal groups of 40, and 32 of the treated women and 33 control completed the study. We considered a change in the Short Physical Performance Battery (SPPB) score as the primary outcome and changes in the peak torque (PT) isometric and isokinetic strength of the lower limbs, 6-minute walking test (6MWT), handgrip strength and endurance as secondary outcomes. Body composition was assessed with dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computerized tomography (pQCT). The mean difference between the two groups on pre-post change were finally calculated (delta) for each outcome. After 8 weeks, there were no significant differences between the groups’ SPPB, handgrip strength or DXA parameters. The group treated with HMB scored significantly better than the control group for PT isokinetic flexion (delta = 1.56±1.56 Nm; p = 0.03) and extension (delta = 3.32±2.61 Nm; p = 0.03), PT isometric strength (delta = 9.74±3.90 Nm; p = 0.02), 6MWT (delta = 7.67±8.29 m; p = 0.04), handgrip endurance (delta = 21.41±16.28 s; p = 0.02), and muscle density assessed with pQCT. No serious adverse effects were reported in either group. In conclusion, a nutritional supplement containing 1.5 g of calcium HMB for 8 weeks in healthy elderly women had no significant effects on SPPB, but did significantly improve several muscle strength and physical performance parameters. ClinicalTrials.gov NCT02118181.

  10. Validity, Reliability, and Performance Determinants of a New Job-Specific Anaerobic Work Capacity Test for the Norwegian Navy Special Operations Command.

    Science.gov (United States)

    Angeltveit, Andreas; Paulsen, Gøran; Solberg, Paul A; Raastad, Truls

    2016-02-01

    Operators in Special Operation Forces (SOF) have a particularly demanding profession where physical and psychological capacities can be challenged to the extremes. The diversity of physical capacities needed depend on the mission. Consequently, tests used to monitor SOF operators' physical fitness should cover a broad range of physical capacities. Whereas tests for strength and aerobic endurance are established, there is no test for specific anaerobic work capacity described in the literature. The purpose of this study was therefore to evaluate the reliability, validity, and to identify performance determinants of a new test developed for testing specific anaerobic work capacity in SOF operators. Nineteen active young students were included in the concurrent validity part of the study. The students performed the evacuation (EVAC) test 3 times and the results were compared for reliability and with performance in the Wingate cycle test, 300-m sprint, and a maximal accumulated oxygen deficit (MAOD) test. In part II of the study, 21 Norwegian Navy Special Operations Command operators conducted the EVAC test, anthropometric measurements, a dual x-ray absorptiometry scan, leg press, isokinetic knee extensions, maximal oxygen uptake test, and countermovement jump (CMJ) test. The EVAC test showed good reliability after 1 familiarization trial (intraclass correlation = 0.89; coefficient of variance = 3.7%). The EVAC test correlated well with the Wingate test (r = -0.68), 300-m sprint time (r = 0.51), and 300-m mean power (W) (r = -0.67). No significant correlation was found with the MAOD test. In part II of the study, height, body mass, lean body mass, isokinetic knee extension torque, maximal oxygen uptake, and maximal power in a CMJ was significantly correlated with performance in the EVAC test. The EVAC test is a reliable and valid test for anaerobic work capacity for SOF operators, and muscle mass, leg strength, and leg power seem to be the most important determinants

  11. Does external pneumatic compression treatment between bouts of overreaching resistance training sessions exert differential effects on molecular signaling and performance-related variables compared to passive recovery? An exploratory study.

    Directory of Open Access Journals (Sweden)

    Cody T Haun

    Full Text Available We sought to compare the effects of external pneumatic compression (EPC and sham when used concurrently with resistance training on performance-related outcomes and molecular measures related to recovery.Twenty (N = 20 resistance-trained male participants (aged 21.6±2.4 years were randomized to balanced sham or EPC intervention groups. The protocol consisted of 3 consecutive days of heavy, voluminous back squat exercise followed by EPC/sham treatment (Days2-4 and 3 consecutive days of recovery (Days5-7 with EPC/sham only on Days5-6. On Day1 (PRE, and Days3-7, venipuncture, flexibility and pressure-to-pain threshold (PPT measures were performed. Vastsus lateralis muscle tissue was biopsied at PRE, 1-h post-EPC/sham treatment on Day2 (POST1 and 24-h post-EPC/sham treatment on Day7 (POST2. Isokinetic peak torque was assessed at PRE and POST2.Peak isokinetic strength did not change from PRE to POST2 in either group. The PPT was significantly lower on Days3-6 with sham, indicating greater muscle soreness, though this was largely abolished in the EPC group. A significant decrease in flexibility with sham was observed on Day3 (+16.2±4.6% knee joint angle; P0.01. Vastus lateralis poly-ubiquitinated proteins significantly increased at the POST2 time point relative to PRE with sham (+66.6±24.6%; P<0.025 and were significantly greater (P<0.025 than those observed with EPC at the same time point (-18.6±8.5%. 4-hydroxynonenal values were significantly lower at POST2 relative to PRE with EPC (-16.2±5.6%; P<0.025 and were significantly lower (P<0.025 than those observed with sham at the same time point (+11.8±5.9%.EPC mitigated a reduction in flexibility and PPT that occurred with sham. Moreover, EPC reduced select skeletal muscle oxidative stress and proteolysis markers during recovery from heavy resistance exercise.

  12. Laboratory- and field-based testing as predictors of skating performance in competitive-level female ice hockey.

    Science.gov (United States)

    Henriksson, Tommy; Vescovi, Jason D; Fjellman-Wiklund, Anncristine; Gilenstam, Kajsa

    2016-01-01

    The purpose of this study was to examine whether field-based and/or laboratory-based assessments are valid tools for predicting key performance characteristics of skating in competitive-level female hockey players. Cross-sectional study. Twenty-three female ice hockey players aged 15-25 years (body mass: 66.1±6.3 kg; height: 169.5±5.5 cm), with 10.6±3.2 years playing experience volunteered to participate in the study. The field-based assessments included 20 m sprint, squat jump, countermovement jump, 30-second repeated jump test, standing long jump, single-leg standing long jump, 20 m shuttle run test, isometric leg pull, one-repetition maximum bench press, and one-repetition maximum squats. The laboratory-based assessments included body composition (dual energy X-ray absorptiometry), maximal aerobic power, and isokinetic strength (Biodex). The on-ice tests included agility cornering s-turn, cone agility skate, transition agility skate, and modified repeat skate sprint. Data were analyzed using stepwise multivariate linear regression analysis. Linear regression analysis was used to establish the relationship between key performance characteristics of skating and the predictor variables. Regression models (adj R (2)) for the on-ice variables ranged from 0.244 to 0.663 for the field-based assessments and from 0.136 to 0.420 for the laboratory-based assessments. Single-leg tests were the strongest predictors for key performance characteristics of skating. Single leg standing long jump alone explained 57.1%, 38.1%, and 29.1% of the variance in skating time during transition agility skate, agility cornering s-turn, and modified repeat skate sprint, respectively. Isokinetic peak torque in the quadriceps at 90° explained 42.0% and 32.2% of the variance in skating time during agility cornering s-turn and modified repeat skate sprint, respectively. Field-based assessments, particularly single-leg tests, are an adequate substitute to more expensive and time

  13. Effect of 12-Week Vitamin D Supplementation on 25[OH]D Status and Performance in Athletes with a Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Joelle Leonie Flueck

    2016-09-01

    Full Text Available (1 Background: studies with able-bodied athletes showed that performance might possibly be influenced by vitamin D status. Vitamin D seems to have a direct impact on neuromuscular function by docking on vitamin D receptors in the muscle tissue. Additionally, a high prevalence of vitamin D deficiency was shown not only in infants and in the elderly but also in healthy adults and spinal cord injured individuals. Therefore, the aim of our study was to investigate whether a vitamin D dose of 6000 IU daily over 12 weeks would be sufficient to increase vitamin D status in indoor wheelchair athletes to a normal or optimal vitamin D level and whether vitamin D deficiency is associated with an impairment in muscle performance in these individuals; (2 Methods: vitamin D status was assessed in indoor elite wheelchair athletes in order to have a baseline measurement. If vitamin D status was below 75 nmol/L, athletes were supplemented with 6000 IU of vitamin D daily over 12 weeks. A vitamin D status over 75 nmol/L was supplemented with a placebo supplement. Vitamin D status, as well as a Wingate test and an isokinetic dynamometer test, were performed at baseline and after six and 12 weeks; (3 Results: 20 indoor elite wheelchair athletes participated in this double-blind study. All of these athletes showed an insufficient vitamin D status at baseline and were, therefore, supplemented with vitamin D. All athletes increased vitamin D status significantly over 12 weeks and reached an optimal level. Wingate performance was not significantly increased. Isokinetic dynamometer strength was significantly increased but only in the non-dominant arm in isometric and concentric elbow flexion; (4 Conclusion: a dose of 6000 IU of vitamin D daily over a duration of 12 weeks seems to be sufficient to increase vitamin D status to an optimal level in indoor wheelchair athletes. It remains unclear, whether upper body performance or muscle strength and vitamin D status are

  14. Abdominal muscle function and incisional hernia

    DEFF Research Database (Denmark)

    Jensen, K K; Kjaer, M; Jorgensen, L N

    2014-01-01

    PURPOSE: Although ventral incisional hernia (VIH) repair in patients is often evaluated in terms of hernia recurrence rate and health-related quality of life, there is no clear consensus regarding optimal operative treatment based on these parameters. It was proposed that health-related quality...... of life depends largely on abdominal muscle function (AMF), and the present review thus evaluates to what extent AMF is influenced by VIH and surgical repair. METHODS: The PubMed and EMBASE databases were searched for articles following a systematic strategy for inclusion. RESULTS: A total of seven...... studies described AMF in relation to VIH. Five studies examined AMF using objective isokinetic dynamometers to determine muscle strength, and two studies examined AMF by clinical examination-based muscle tests. CONCLUSION: Both equipment-related and functional muscle tests exist for use in patients...

  15. Correlation analysis of reactivity in the oxidation of some organic diols by tripropylammonium fluorochromate in non-aqueous media

    Directory of Open Access Journals (Sweden)

    S. Sheik Mansoor

    2016-09-01

    Full Text Available The kinetics of oxidation of some organic diols by tripropylammonium fluorochromate (TriPAFC have been studied in dimethylsulfoxide (DMSO. The main product of oxidation is the corresponding hydroxy aldehydes. The reaction is first order with respect to TriPAFC and exhibited Michaelis-Menten type kinetics with respect to organic diols. The reaction is catalyzed by hydrogen ions. The hydrogen ion dependence has the form: kobs = a + b[H+]. Various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of isokinetic relationship. Oxidation of diols was studied in 18 different organic solvents. The rate data are showing satisfactory correlation with Kamlet–Taft solvotochromic parameters (α, β and π∗. A suitable mechanism of oxidation has been proposed.

  16. Dynamic plantar pressure distribution, strength capacity and postural control after Lisfranc fracture-dislocation

    DEFF Research Database (Denmark)

    Mehlhorn, Alexander T; Walther, Markus; Yilmaz, Tayfun

    2017-01-01

    of life. 17 consecutive patients suffering from a Lisfranc fracture dislocation were registered, underwent open reduction and internal fixation and were followed-up for 50.5±25.7months (Mean±SDM). Biomechanical analysis of muscle strength capacities, postural control and plantar pressure distribution......Substantial progress has been made in the operative treatment of Lisfranc fractures, however, the prognosis remains poor. We hypothesized that Lisfranc injuries change the postural control and muscle strength of the lower limb. Both are suggested to correlate with the clinical outcome and quality...... correlated well with clinical outcome. Altered postural control was evident by a significant reduction in unilateral stance time, from which we calculated a strong correlation between stance time and the isokinetic strength measurement. Plantar pressure measurements revealed a significant reduction in peak...

  17. Operating manual for Ford's Farm Range air samplers

    International Nuclear Information System (INIS)

    Glissmeyer, J.A.; Halverson, M.A.

    1980-10-01

    An air-sampling program was designed for a target enclosure at the Ford's Farm Range, Aberdeen Proving Ground, Maryland, where the Army test-fires tungsten and depleted-uranium armor penetrators. The primary potential particle inhalation hazard is depleted uranium. The sampling program includes workplace and filtered exhaust air sampling. Conventional isokinetic stack sampling was employed for the filtered exhaust air. Because of the need for rapid monitor response to concentration increases and decreases, conventional radioactive particle monitors were not used. Instead, real-time aerosol monitors employing a light-scattering technique were used for monitors requiring a fast response. For other monitoring functions, piezoelectric and beta-attenuation respirable-particle sampling techniques were used. The application of these technologies to the monitoring of airborne radioactive contaminants is addressed. Sampler installation and operation are detailed

  18. Experimental knee pain reduces muscle strength

    DEFF Research Database (Denmark)

    Henriksen, Marius; Mortensen, Sara Rosager; Aaboe, Jens

    2011-01-01

    Pain is the principal symptom in knee pathologies and reduced muscle strength is a common observation among knee patients. However, the relationship between knee joint pain and muscle strength remains to be clarified. This study aimed at investigating the changes in knee muscle strength following...... experimental knee pain in healthy volunteers, and if these changes were associated with the pain intensities. In a crossover study, 18 healthy subjects were tested on 2 different days. Using an isokinetic dynamometer, maximal muscle strength in knee extension and flexion was measured at angular velocities 0....... Knee pain reduced the muscle strength by 5 to 15% compared to the control conditions (P knee extension and flexion at all angular velocities. The reduction in muscle strength was positively correlated to the pain intensity. Experimental knee pain significantly reduced knee extension...

  19. Low-Budget Instrumentation of a Conventional Leg Press to Measure Reliable Isometric-Strength Capacity.

    Science.gov (United States)

    Baur, Heiner; Groppa, Alessia Severina; Limacher, Regula; Radlinger, Lorenz

    2016-02-02

    Maximum strength and rate of force development (RFD) are 2 important strength characteristics for everyday tasks and athletic performance. Measurements of both parameters must be reliable. Expensive isokinetic devices with isometric modes are often used. The possibility of cost-effective measurements in a practical setting would facilitate quality control. The purpose of this study was to assess the reliability of measurements of maximum isometric strength (Fmax) and RFD on a conventional leg press. Sixteen subjects (23 ± 2 y, 1.68 ± 0.05 m, 59 ± 5 kg) were tested twice within 1 session. After warm-up, subjects performed 2 times 5 trials eliciting maximum voluntary isometric contractions on an instrumented leg press (1- and 2-legged randomized). Fmax (N) and RFD (N/s) were extracted from force-time curves. Reliability was determined for Fmax and RFD by calculating the intraclass correlation coefficient (ICC), the test-retest variability (TRV), and the bias and limits of agreement. Reliability measures revealed good to excellent ICCs of .80-.93. TRV showed mean differences between measurement sessions of 0.4-6.9%. The systematic error was low compared with the absolute mean values (Fmax 5-6%, RFD 1-4%). The implementation of a force transducer into a conventional leg press provides a viable procedure to assess Fmax and RFD. Both performance parameters can be assessed with good to excellent reliability allowing quality control of interventions.

  20. The Acute Effect of Cryotherapy on Muscle Strength and Shoulder Proprioception.

    Science.gov (United States)

    Torres, Rui; Silva, Filipa; Pedrosa, Vera; Ferreira, João; Lopes, Alexandre

    2017-11-01

    Cryotherapy, a common intervention used by clinicians, poses several benefits in managing acute injuries. However, cooling muscle tissue can interfere with muscular properties and the sensory-motor system. The aim of this study was to analyze the influence of cryotherapy with a crushed-ice pack on shoulder proprioception concerning joint position sense, force sense, the threshold for detecting passive movement, and maximal force production. A randomized, double-blind controlled trial. 48 healthy women aged 22.6 ± 0.4 y with a mean body mass index of 22.8 ±0.37 kg/m2 and a percentage of body fat of 15.4 ± 1.5%. In the experimental group, a crushed-ice pack was applied to the shoulder for 15 min, whereas participants in the control group applied a sandbag at skin temperature, also for 15 min. An isokinetic dynamometer was used to assess maximal voluntary contraction, force sense, joint position sense, and the threshold for detecting passive movement. Paired sample t tests revealed that maximal voluntary isometric contraction decreased significantly after cryotherapy (P ≤ .001), or approximately 10% of the reduction found in both muscular groups assessed. Shoulder position sense (P < .001) and the threshold for detecting passive movement (P = .01 and P = .01 for lateral and medial shoulder rotator muscles, respectively) also suffered significant impairment. Nevertheless, no significant differences emerged in force sense at 20% and 50% of maximal force reproduction (P = .41 and P = .10 for lateral rotator muscles at 20% and 50%, respectively; and P = .20 and P = .09 for medial rotator muscles at 20% and 50%, respectively). Applying a crushed-ice pack to the shoulder for 15 min negatively affected muscle strength and impaired shoulder proprioception by decreasing joint position sense and the threshold for detecting passive movement.

  1. A comparison of two Shuttle launch and entry suits - Reach envelope, isokinetic strength, and treadmill tests

    Science.gov (United States)

    Schafer, Lauren E.; Rajulu, Sudhakar L.; Klute, Glenn K.

    1992-01-01

    A quantification has been conducted of any existing differences between the performance, in operational conditions, of the Space Shuttle crew Launch Entry Suit (LES) and the new Advanced Crew Escape Suit (ACES). While LES is a partial-pressure suit, the ACES system which is being considered as a replacement for LES is a full-pressure suit. Three tests have been conducted with six subjects to ascertain the suits' reach envelope, strength, and treadmill performance. No significant operational differences were found between the two suit designs.

  2. Banking contracts

    OpenAIRE

    Durčáková, Klára

    2010-01-01

    Resumé - Bank Contracts Bank Contracts are an integral part of our everyday lives. Citizen and bussines entities used bank contracts very often. Despite this fact we can't find legal definition in the Czech law. Banking contracts understand contracts that are signed by banks in their business activities and obligations under these contracts arise. While the banking contracts have been widely used, in Czech law there is not too much literature and judgements abou this issue. Lack of legislatio...

  3. Subcutaneous immunoglobulin as first-line therapy in treatment-naive patients with chronic inflammatory demyelinating polyneuropathy

    DEFF Research Database (Denmark)

    Markvardsen, L H; Sindrup, S H; Christiansen, I

    2017-01-01

    BACKGROUND AND PURPOSE: Subcutaneous immunoglobulin (SCIG) is effective as maintenance treatment in chronic inflammatory demyelinating polyneuropathy (CIDP). We investigated whether multiple subcutaneous infusions are as effective as conventional therapy with intravenous loading doses in treatment...... treatment arm and followed for a further 10 weeks. All participants were evaluated at weeks 0, 2, 5 and 10 during both therapies. Primary outcome was combined isokinetic muscle strength (cIKS). Secondary outcomes were disability, clinical evaluation of muscle strength and the performance of various function...... tests. RESULTS: All participants received both therapies, 14 completing the protocol. Overall, cIKS increased by 7.4 ± 14.5% (P = 0.0003) during SCIG and by 6.9 ± 16.8% (P = 0.002) during IVIG, the effect being similar (P = 0.80). Improvement of cIKS peaked 2 weeks after IVIG and 5 weeks after SCIG...

  4. Correlation analysis of reactivity in the oxidation of some para- substituted benzhydrols by triethylammonium chlorochromate in non-aqueous media

    Directory of Open Access Journals (Sweden)

    S. Sheik Mansoor

    2017-02-01

    Full Text Available Triethylammonium chlorochromate (TriEACC oxidation of some para-substituted benzhydrols (BH in dimethylsulfoxide (DMSO leads to the formation of corresponding benzophenones. The reaction was run under pseudo-first-order conditions. The reaction is catalyzed by hydrogen ions. The hydrogen ion dependence has the form: kobs = a + b[H+]. Various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of isokinetic relationship. Oxidation of benzhydrol was studied in 18 different organic solvents. The rate data showing satisfactory correlation with Kamlet–Taft solvatochromic parameters (α, β and π∗ suggests that the specific solute–solvent interactions play a major role in governing the reactivity, and the observed solvent effects have been explained on the basis of solute–solvent complexation. A suitable mechanism of oxidation has been proposed.

  5. Impact of high intensity exercise on muscle morphology in EAE rats

    DEFF Research Database (Denmark)

    Wens, I; Dalgas, U; Verboven, K

    2015-01-01

    paralysis (experiment 2, n=40), isokinetic foot extensor strength, cross sectional area (CSA) of tibialis anterior (TA), extensor digitorum longus (EDL) and soleus (SOL) and brain-derived neurotrophic factor (BDNF) levels were assessed. EAE reduced muscle fiber CSA of TA, EDL and SOL. In general, exercise......The impact of high-intensity exercise on disease progression and muscle contractile properties in experimental autoimmune encephalomyelitis (EAE) remains unclear. Control (CON) and EAE rats were divided into sedentary and exercise groups. Before onset (experiment 1, n=40) and after hindquarter...... was not able to affect CSA, whereas it delayed hindquarter paralysis peak. CON muscle work peaked and declined, while it remained stable in EAE. BDNF-responses were not affected by EAE or exercise. In conclusion, EAE affected CSA-properties of TA, EDL and SOL, which could, partly, explain the absence of peak...

  6. Experimental investigation of the enthalpy and mass flow distribution between subchannels in a BWR cluster geometry (PELCO-S)

    International Nuclear Information System (INIS)

    Herkenrath, H.; Hufschmidt, W.

    1979-01-01

    Experiments based on the subchannel isokinetic technique have been carried out at the JRC of the European Community at Ispra, using a purposely designed 16-rod test section, simulating in a rather accurate way a typical BWR geometry. The adopted system allows the simultaneous determination of mass flow and enthalpy, at the end of the bundle active length, in four characteristic subchannels of the 16-rod lattice. The results show some pronounced flow and enthalpy variations within the bundle, not accurately taken into account by current subchannel codes, such as COBRA-3C. In particular low values both in mass flow and enthalpy have been found in corner subchannel, in disagreement with code predictions, but confirming previous General Electric experiments carried out in a 9-rod test section. This report deals only with the experimental procedure and the results

  7. Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity

    DEFF Research Database (Denmark)

    Holm, L.; Reitelseder, S.; Pedersen, T.G.

    2008-01-01

    resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P ...Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same...... individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic...

  8. Improved skeletal muscle mass and strength after heavy strength training in very old individuals

    DEFF Research Database (Denmark)

    Bechshøft, Rasmus Leidesdorff; Malmgaard-Clausen, Nikolaj Mølkjær; Gliese, Bjørn

    2017-01-01

    , muscle fiber type distribution and size did not differ significantly between groups. We conclude that in protein supplemented very old individuals, heavy resistance training can increase muscle mass and strength, and that the relative improvement in mass is more pronounced when initial muscle mass is low.......Age-related loss of muscle mass and function represents personal and socioeconomic challenges. The purpose of this study was to determine the adaptation of skeletal musculature in very old individuals (83 + years) performing 12 weeks of heavy resistance training (3 ×/week) (HRT) compared to a non....... The increase in CSA is correlated inversely with the baseline level of CSA (R2 = 0.43, P muscle isometric strength, isokinetic peak torque and power increased significantly only in HRT by 10–15%, whereas knee extension one-repetition maximum (1 RM) improved by 91%. Physical functional tests...

  9. Relationships between the fibromyalgia impact questionnaire, tender point count, and muscle strength in female patients with fibromyalgia

    DEFF Research Database (Denmark)

    Henriksen, Marius; Lund, Hans; Christensen, Robin

    2009-01-01

    of the patients completed version 1 of the Fibromyalgia Impact Questionnaire (FIQ) and were assessed for tender points and knee muscle strength. All subjects underwent bilateral isokinetic knee muscle strength testing in flexion and extension. Normative knee muscle strength values were calculated from the healthy......OBJECTIVE: To test the hypothesis that fibromyalgia (FM) patients with reduced lower extremity strength are more symptomatic and tender than FM patients with normal muscle strength. METHODS: A total of 840 FM patients and 122 healthy subjects were evaluated between 1998 and 2005. All....... There were no clinically significant differences between patients with low versus normal muscle strength. There were no clinically significant correlations between total FIQ score, tender point count, and muscle strength. Only 4.6% of the FIQ scores and 5.1% of the tender point counts were explained...

  10. 23 CFR 635.121 - Contract time and contract time extensions.

    Science.gov (United States)

    2010-04-01

    ... TRAFFIC OPERATIONS CONSTRUCTION AND MAINTENANCE Contract Procedures § 635.121 Contract time and contract time extensions. (a) The STD should have adequate written procedures for the determination of contract... 23 Highways 1 2010-04-01 2010-04-01 false Contract time and contract time extensions. 635.121...

  11. The effects of knee extensor eccentric training on functional tests in healthy subjects Os efeitos do treino isocinético excêntrico dos extensores do joelho nos testes funcionais em sujeitos saudáveis

    Directory of Open Access Journals (Sweden)

    Heleodório H. Santos

    2010-08-01

    Full Text Available BACKGROUND: It is well known that eccentric training increases muscle strength and promotes greater neural activation, and therefore has been used in the recovery of knee extensors. The hypothesis of this study was that there would be a strong correlation between knee extensor torque and functional tests. OBJECTIVES: To investigate the relationship between knee extensor peak torque and functional tests of agility (runs and propulsion (hop for distance after short-term isokinetic eccentric training. METHODS: Twenty healthy and active male undergraduate students (age 22.5±2.1 years; height 1.72±0.10 m; weight 67.8±9.5 kg; body mass index: 22.5±2.0 kg/m², with no abnormalities or history of injury of the limbs, performed an isokinetic assessment of the knee extensors and flexors and also functional tests before and after isokinetic training, which consisted of 3 sets of 10 MVECs at 30º/s, with 3 minutes of rest between sets, twice a week for 6 weeks. RESULTS: The eccentric training increased the extensor peak torque (16, 27 and 17%; PCONTEXTUALIZAÇÃO: Sabe-se que o treino excêntrico aumenta a força muscular, promovendo uma maior ativação neural e, portanto, tem sido usado na recuperação do torque extensor. A hipótese deste estudo foi a de que possa existir uma forte correlação entre o torque extensor do joelho e os testes funcionais. OBJETIVOS: Correlacionar o torque extensor do joelho com os testes funcionais de agilidade (corridas e impulsão (saltos em distância após o treino isocinético excêntrico de curta duração. MÉTODOS: Vinte homens universitários, ativos e saudáveis (22,5±2,1 anos; 1,72±0,10 m; 67,8±9,5 kg; IMC 22,5±2,0 kg/m², sem reportar anormalidades ou história de lesão no membro inferior, realizaram avaliação isocinética do torque extensor e flexor do joelho e testes funcionais antes e depois do treino isocinético que consistiu em três séries de 10 CEVM a 30º/s, com 3 minutos de repouso entre as

  12. Perfil antropométrico e fisiológico de atletas brasileiros de "rugby" Anthropometric and physiological profile of Brazilian rugby athletes

    Directory of Open Access Journals (Sweden)

    André Luiz Lopes

    2011-09-01

    Full Text Available O "Rugby" é um esporte bastante popular internacionalmente e em franca ascensão no Brasil. É caracterizado pela existência de duas posições táticas básicas ("forwards" e "backs", cujos atletas apresentam demandas funcionais e características físicas distintas. Embora a literatura internacional apresente um número interessante de referências acerca do perfil antropométrico e fisiológico destes atletas, pouca atenção tem sido despendida aos atletas brasileiros. Assim, este trabalho teve como objetivo verificar o desempenho de 20 jogadores amadores de "Rugby" submetidos à ergoespirometria, teste de Wingate e Dinamometria isocinética bem como a comparação entre "backs" (n = 10 e "forwards" (n = 10 para verificar possíveis diferenças entre as posições táticas. Para determinação dos valores de VO2 e VCO2 foi utilizado um analisador de gases computadorizado (CPX-D; MedGraphics Cardiorespiratory Diagnostic Systems para variáveis de força um dinamômetro isocinético Cybex Norm (Lumex & Co., Ronkonkoma, USA e para comparações de composição corporal foi aplicada a técnica de cinco componentes da ISAK. A comparação entre os dados foi verificada por meio do teste t de Student para amostras independentes, sendo que para todas as variáveis foi adotado um índice de significância de p Rugby is a very popular sport around the world and on the rise in Brazil. It is characterized by the existence of two basic tactics positions (forwards and backs, in which athletes have distinguishing functional demands and physical characteristics. Although the international literature presents a number of interesting data about the physiological and anthropometric profile of these athletes, little attention has been spent to Brazilian athletes. This study aimed to verify the performance of 20 amateur rugby players and to compare the aerobic power (VO2max, anaerobic endurance and isokinetic strength in backs (n = 10 and forwards (n = 10. A

  13. Isokinetic and Isometric Muscle Strength in a Healthy Population – with Special Reference to Age and Gender

    DEFF Research Database (Denmark)

    Danneskiold-Samsøe, B; Bartels, E M; Bülow, P M

    2009-01-01

    decreases in a linear fashion from the age of 25 years down to between 54% and 89% at the age of 75 years, and seems not highly dependent on any other parameter than age. For women, the muscle strength is dependent on weight and is only related to age from around 40 years of age. The decrease in muscle...

  14. Standard form contracts and a smart contract future

    Directory of Open Access Journals (Sweden)

    Kristin B. Cornelius

    2018-05-01

    Full Text Available With a budding market of widespread smart contract implementation on the horizon, there is much conversation about how to regulate this new technology. Discourse on standard form contracts (SFCs and how they have been adopted in a digital environment is useful toward predicting how smart contracts might be interpreted. This essay provides a critical review of the discourse surrounding digitised SFCs and applies it to issues in smart contract regulation. An exploration of the literature surrounding specific instances SFCs finds that it lacks a close examination of the textual and documentary aspects of SFCs, which are particularly important in a digital environment as a shift in medium prompts a different procedural process. Instead, common perspectives are either based on outdated notions of paper versions of these contracts or on ideologies of industry and business that do not sufficiently address the needs of consumers/users in the digital age. Most importantly, noting the failure of contract law to address the inequities of SFCs in this environment can help prevent them from being codified further with smart contracts.

  15. Immediate effect of selective neuromuscular electrical stimulation on the electromyographic activity of the vastus medialis oblique muscle

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    Denise DalAva Augusto

    2008-07-01

    Full Text Available http://dx.doi.org/10.5007/1980-0037.2008v10n2p155 The Patellofemoral pain syndrome (PFPS is described as an anterior or retropatellar knee pain in the absence of other associated diseases, and has often been associated with dysfunction of the vastus medialis oblique muscle (VMO. However, several studies have demonstrated the impossibility of selectively activating this muscle with exercises. The aim of the present study was to analyze the immediate effect of neuromuscular electrical stimulation of VMO muscle by means of monitoring the electromyographic activity of the vastus medialis oblique (VMO and vastus lateralis (VL muscles. Eighteen healthy women with a mean age of 23.2 years and mean BMI of 20 Kg/m2 were evaluated. The study protocol included electromyographic analysis of VMO and VL muscles, before and immediately after neuromuscular electrical stimulation of the VMO muscle. During the electromyographic analysis, the volunteers performed maximal voluntary isometric contraction in a 60° knee extension on an isokinetic dynamometer. “Russian current” apparatus was used for electrical stimulation. Results: The data analysis demonstrated a signifi cant increase in VMO activation intensity immediately after it had been electrically stimulated (p=0.0125, whereas VL activation intensity exhibited no signifi cant increase (p=0.924. Moreover, a significant increase in the VMO/VL ratio was also detected (p=0.048. In this study it was observed that electrical stimulation modifiedthe VMO/VL ratio, which suggests electrical stimulation has a benefi cial effect on VMO muscle strength.

  16. Enhanced precision of ankle torque measure with an open-unit dynamometer mounted with a 3D force-torque sensor.

    Science.gov (United States)

    Toumi, A; Leteneur, S; Gillet, C; Debril, J-F; Decoufour, N; Barbier, F; Jakobi, J M; Simoneau-Buessinger, Emilie

    2015-11-01

    Many studies have focused on maximum torque exerted by ankle joint muscles during plantar flexion. While strength parameters are typically measured with isokinetic or isolated ankle dynamometers, these devices often present substantial limitations for the measurement of torque because they account for force in only 1 dimension (1D), and the device often constrains the body in a position that augments torque through counter movements. The purposes of this study were to determine the contribution of body position to ankle plantar-flexion torque and to assess the use of 1D and 3D torque sensors. A custom designed 'Booted, Open-Unit, Three dimension, Transportable, Ergometer' (B.O.T.T.E.) was used to quantify plantar flexion in two conditions: (1) when the participant was restrained within the unit (locked-unit) and (2) when the participant's position was independent of the ankle dynamometer (open-unit). Ten young males performed maximal voluntary isometric plantar-flexion contractions using the B.O.T.T.E. in open and locked-unit mechanical configurations. The B.O.T.T.E. was reliable with ICC higher than 0.90, and CV lower than 7 %. The plantar-flexion maximal resultant torque was significantly higher in the locked-unit compared with open-unit configuration (P torque sensor significantly underestimated the proper capacity of plantar-flexion torque production (P torque should be performed with an open-unit dynamometer mounted with a 3D sensor that is exclusive of accessory muscles but inclusive of all ankle joint movements.

  17. Kinetic analysis of concurrent activation potentiation during back squats and jump squats.

    Science.gov (United States)

    Ebben, William P; Kaufmann, Clare E; Fauth, McKenzie L; Petushek, Erich J

    2010-06-01

    Concurrent activation potentiation enhances muscular force during open kinetic chain isometric and isokinetic exercises via remote voluntary contractions (RVCs). The purpose of this study was to evaluate the effect of RVCs on the performance of closed kinetic chain ground-based exercises. Subjects included 13 men (21.4+/-1.5 years) who performed the back squat and jump squat in 2 test conditions. The RVC condition included performing the test exercises while clenching the jaw on a mouth guard, forcefully gripping and pulling the barbell down into the trapezius, and performing a Valsalva maneuver. The normal condition (NO-RVC) included performing the test exercises without RVCs. Exercises were assessed with a force platform. Peak ground reaction force (GRF), rate of force development (RFD) during the first 100 milliseconds (RFD-100), RFD to peak GRF (RFD-P), and jump squat height (JH) were calculated from the force-time records. Data were analyzed using an analysis of variance. Results reveal that GRF and RFD-100 were higher in the RVC compared with the NO-RVC condition for both the back squat and jump squat (psquat (psquat (p=0.82). The JH was higher in the RVC compared to the NO-RVC condition for the jump squat (p

  18. Psychological and Physiological Biomarkers of Neuromuscular Fatigue after Two Bouts of Sprint Interval Exercise

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    Albertas Skurvydas

    2017-12-01

    Full Text Available The main aim of our study was to determinate whether a repeated bout (RB (vs. first bout [FB] of sprint interval cycling exercise (SIE is sufficient to mitigate SIE-induced psychological and physiological biomarker kinetics within 48 h after the exercise. Ten physically active men (age, 22.6 ± 5.2 years; VO2max, 44.3 ± 5.7 ml/kg/min performed the FB of SIE (12 repeats of 5 s each on one day and the RB 2 weeks later. The following parameters were measured: motor performance (voluntary, electrically induced and isokinetic skeletal muscle contraction torque, and central activation ratio [CAR]; stress markers [brain-derived neurotrophic factor (BDNF, cortisol, norepinephrine, and epinephrine]; inflammatory markers (IL-6, IL-10, and TNF-α; metabolic markers (glucose and lactate; muscle and rectal temperature; cycling power output; and psychological perceptions. The average cycling power output and neuromuscular fatigue after exercise did not differ between the FB and RB. There were significant decreases in cortisol and BDNF concentration at 12 h (P < 0.05 and 24 h (P < 0.001 after the FB, respectively. The decrease in cortisol concentration observed 12 h after exercise was significantly greater after the RB (P < 0.05 than after the FB. The immune-metabolic response to the RB (vs. FB SIE was suppressed and accompanied by lower psychological exertion. Most of the changes in psychological and physiological biomarkers in the FB and RB were closely related to the response kinetics of changes in BDNF concentration.

  19. Effects of weightlessness on the muscle system. new results of simulation's studies

    Science.gov (United States)

    Kozlovskaya, I. B.; Shenkman, B. S.; Grigoriev, A. I.

    Results of studies of phenomenology and nature of the hypogravitational motor syndrome, provided at the Institute of Biomedical Problems of RAS, have shown that a decline of gravitational load is followed consistently by deep disturbances in all parts and structures of the motor system. An important role in their development plays the withdrawal of the support and, accordingly the decrease of the intensity of the support afferentation activities that provokes a decline of tonic motor units' activities and correspondingly a decline of the muscle tone in the first phase and the development of atrophic processes in slow fibers of antigravitational muscles in the second one (Kozlovskaya et.al., 1987). This hypothesis was tested in experiments with 7-hours and 7-days "dry immersion" (DI), in which effects of pure supportless environment and pure supportless environment coupled with mechanical stimulation of the support zones of the soles were compared. Stimulation with the pressure of 0,2 kg/sm^2 value to forefoot and heel support zones for 20 minutes every hour during 6 hours was applied daily in the regimen of slow and fast locomotion (pacing with the rate of 60 and 120 steps/min). The subjects exposed to the pure DI environment revealed after exposition a significant decline of the transverse stiffness and of the maximal isokinetic force of the leg postural muscles, a decrease of the postural muscles participation in the locomotions along with the increase of the phasic muscles' part, a significant decrease of the absolute force of m.soleus single skinned fibers evoked by Ca++, and an obvious decline of their transverse cross sectional areas as well as prominent disturbances of the activities of spinal and supraspinal motor control systems. Mechanical stimulation of the soles support zones eliminated all the above effects, minimizing the changes of the muscle stiffness and the maximal isokinetic force, taking away the signs of the isolated muscle fibers force decline

  20. Peroneal electromechanical delay and fatigue in patients with chronic ankle instability.

    Science.gov (United States)

    Flevas, Dimitrios A; Bernard, Manfred; Ristanis, Stavros; Moraiti, Constantina; Georgoulis, Anastasios D; Pappas, Evangelos

    2017-06-01

    The purpose of this study was to investigate the effect of chronic ankle instability (CAI) on electromechanical delay times (EMD) before and after fatigue. Understanding the mechanisms that contribute to CAI is essential for the development of effective rehabilitation programmes. It was hypothesized that patients with CAI will demonstrate prolonged EMD times compared to healthy subjects and that fatigue will cause greater increases in EMD times in the CAI group. Twenty-one male volunteers participated in the study providing data on 16 ankles with CAI and 26 with no history of ankle injury. EMD was measured on an isokinetic dynamometer. Measurements were taken with the ankle in neutral (0°) and at 30° of inversion. All subjects followed an isokinetic fatigue protocol until eversion torque fell below 50 % of initial torque for three consecutive repetitions. A 2 × 2 × 2 ANOVA was used to calculate the effect of ankle status (CAI vs. healthy), fatigue, angle (0° vs. 30°) and their interactions on EMD. Fatigue caused a significant increase on EMD [non-fatigued: 122(29)ms vs. fatigue 155(54)ms; p ankle status and angle was found (p = 0.026) with CAI ankles demonstrating longer EMD [CAI: 156(45)ms vs. healthy: 133(40)ms] in neutral but not at 30° of inversion [CAI: 133(46)ms vs. 132(33)ms]. Patients with CAI had longer EMD times in neutral, but not when the ankle was placed in inversion. This suggests that rehabilitation programmes may be more effective when retraining occurs with the ankle in neutral position. It is likely that low EMD times prevent ankle acceleration at the beginning of the mechanism of injury, but they are less important when the ankle has already inverted at 30°. Both CAI and healthy subjects demonstrated longer EMD after fatigue, emphasizing the importance of proper conditioning in the prevention of delayed peroneal response and subsequent ankle injury. Improving resistance to fatigue of the peroneals may prove to be an effective