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Sample records for leg extensor muscles

  1. Volume estimation of extensor muscles of the lower leg based on MR imaging

    International Nuclear Information System (INIS)

    Lund, Hans; Christensen, Line; Savnik, Anette; Danneskiold-Samsoee, Bente; Bliddal, Henning; Boesen, Jens

    2002-01-01

    Magnetic resonance imaging can be used to measure the muscle volume of a given muscle or muscle group. The purpose of this study was to determine both the intra- and inter-observer variation of the manually outlined volume of the extensor muscles (tibialis anterior, extensor digitorum longus and extensor hallucis longus), to estimate the minimum number of slices needed for these calculations and to compare estimates of volume based on an assumed conic shape of the muscles with that of an assumed cylindrical shape, the calculation in both cases based on the Cavalieri principle. Eleven young and healthy subjects (4 women and 7 men, age range 24-40 years) participated. Magnetic resonance imaging of the left leg was obtained on a 1.5-T MR system using a knee coil (receive only). A total of 50 consecutive slices were obtained beginning 10 cm below the caput fibula sin. and proceeding distally with a slice thickness of 1.5 mm without gap. The intra-class correlation coefficient (ICC) was used to calculate the relative reliability (interval from 0 to 1.0). A high reliability for both intra- and inter-reliability was observed (ICC 0.98 and 1.0). The difference was only 0.004% between calculations based on measurement of all 50 slices with respect to 8 slices equally distributed along the muscle group. No difference was found between the two different volumetric assumptions in the Cavalieri principle. The manually outlining of extensor muscles volumes was reliable and only 8 slices of the calf were needed. No difference was seen between the two used mathematical calculations. (orig.)

  2. Utilization of stored elastic energy in leg extensor muscles by men and women.

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    Komi, P V; Bosco, C

    1978-01-01

    An alternating cycle of eccentric-concentric contractions in locomotion represents a sequence when storage and utilization of elastic energy takes place. It is possible that this storage capacity and its utilization depends on the imposed stretch loads in activated muscles, and that sex differences may be present in these phenomena. To investigate these assumed differences, subjects from both sexes and of good physical condition performed vertical jumps on the force-platform from the following experimental conditions: squatting jump (SJ) from a static starting position; counter-movement jump (CMJ) from a free standing position and with a preparatory counter-movement; drop jumps (DJ) from the various heights (20 to 100 cm) on to the platform followed immediately by a vertical jump. In all subjects the SJ, in which condition no appreciable storage of elastic energy takes place, produced the lowest height of rise of the whole body center of gravity (C.G.). The stretch load (drop height) influenced the performance so that height of rise of C. of G. increased when the drop height increased from 26 up to 62 cm (males) and from 20 to 50 cm (females). In all jumping conditions the men jumped higher than the women. However, examination of the utilization of elastic energy indicated that in CMJ the female subjects were able to utilize most (congruent to 90%) of the energy produced in the prestretching phase. Similarly, in DJ the overall change in positive energy over SJ condition was higher in women as compared to men. Thus the results suggest that although the leg extensor muscles of the men subjects could sustain much higher stretch loads, the females may be able to utilize a greater portion of the stored elastic energy in jumping activities.

  3. 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.

  4. Strength and power of knee extensor muscles

    Directory of Open Access Journals (Sweden)

    Knežević Olivera

    2011-01-01

    Full Text Available In the studies of human neuromuscular function, the function of leg muscles has been most often measured, particularly the function of the knee extensors. Therefore, this review will be focused on knee extensors, methods for assessment of its function, the interdependence of strength and power, relations that describe these two abilities and the influence of various factors on their production (resistance training, stretching, movement tasks, age, etc.. Given that it consists of four separate muscles, the variability of their anatomical characteristics affects their participation in strength and power production, depending on the type of movement and motion that is performed. Since KE is active in a variety of activities it must be able to generate great strength in a large and diverse range of muscle lengths and high shortening velocities, in respect to different patterns of strength production, and thus different generation capacities within the muscle (Blazevich et al., 2006. It has been speculated that KE exerts its Pmax at workloads close to subject's own body weight or lower (Rahmani et al., 2001, which is very close to the maximum dynamic output hypothesis (MDI of Jaric and Markovic (2009. Changes under the influence of resistance training or biological age are variously manifested in muscle's morphological, physiological and neural characteristics, and thus in strength and power. Understanding the issues related to strength and power as abilities of great importance for daily activities, is also important for sports and rehabilitation. Performances improvement in sports in which leg muscles strength and power are crucial, as well as recovery after the injuries, are largely dependent on the research results regarding KE function. Also, the appropriate strength balance between knee flexors and extensors is important for the knee joint stability, so that the presence of imbalance between these two muscle groups might be a risk factor for

  5. Effect of exercise-induced enhancement of the leg-extensor muscle-tendon unit capacities on ambulatory mechanics and knee osteoarthritis markers in the elderly.

    Science.gov (United States)

    Karamanidis, Kiros; Oberländer, Kai Daniel; Niehoff, Anja; Epro, Gaspar; Brüggemann, Gert-Peter

    2014-01-01

    Leg-extensor muscle weakness could be a key component in knee joint degeneration in the elderly because it may result in altered muscular control during locomotion influencing the mechanical environment within the joint. This work aimed to examine whether an exercise-induced enhancement of the triceps surae (TS) and quadriceps femoris (QF) muscle-tendon unit (MTU) capacities would affect mechanical and biological markers for knee osteoarthritis in the elderly. Twelve older women completed a 14-week TS and QF MTU exercise intervention, which had already been established as increasing muscle strength and tendon stiffness. Locomotion mechanics and serum cartilage oligomeric matrix protein (COMP) levels were examined during incline walking. MTU mechanical properties were assessed using simultaneously ultrasonography and dynamometry. Post exercise intervention, the elderly had higher TS and QF contractile strength and tendon-aponeurosis stiffness. Regarding the incline gait task, the subjects demonstrated a lower external knee adduction moment and lower knee adduction angular impulse during the stance phase post-intervention. Furthermore, post-intervention compared to pre-intervention, the elderly showed lower external hip adduction moment, but revealed higher plantarflexion pushoff moment. The changes in the external knee adduction moment were significantly correlated with the improvement in ankle pushoff function. Serum COMP concentration increased in response to the 0.5-h incline walking exercise with no differences in the magnitude of increment between pre- and post-intervention. This work emphasizes the important role played by the ankle pushoff function in knee joint mechanical loading during locomotion, and may justify the inclusion of the TS MTU in prevention programs aiming to positively influence specific mechanical markers for knee osteoarthritis in the elderly. However, the study was unable to show that COMP is amenable to change in the elderly following a

  6. Muscle protein degradation and amino acid metabolism during prolonged knee-extensor exercise in humans

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Saltin, B; Wagenmakers, A J

    1999-01-01

    to a substantial increase in net muscle protein degradation, and that a lowering of the starting muscle glycogen content leads to a further increase. The carbon atoms of the branched-chain amino acids (BCAA), glutamate, aspartate and asparagine, liberated by protein degradation, and the BCAA and glutamate......The aim of this study was to investigate whether prolonged one-leg knee-extensor exercise enhances net protein degradation in muscle with a normal or low glycogen content. Net amino acid production, as a measure of net protein degradation, was estimated from leg exchange and from changes...... in the concentrations of amino acids that are not metabolized in skeletal muscle. Experiments were performed at rest and during one-leg knee-extensor exercise in six subjects having one leg with a normal glycogen content and the other with a low glycogen content. Exercise was performed for 90 min at a workload of 60...

  7. Knee extensor muscle strength in middle-aged and older individuals undergoing arthroscopic partial meniscectomy

    DEFF Research Database (Denmark)

    Hall, Michelle; Juhl, Carsten B; Lund, Hans

    2015-01-01

    OBJECTIVE: People with meniscal tears are at high risk to develop or progress knee osteoarthritis. Knee extensor weakness is considered a risk factor for osteoarthritis and is often reported in these individuals. The purpose of this systematic review and meta-analysis was to investigate knee...... for a meniscal tear and used either a healthy control group or the contralateral leg to compare knee extensor muscle strength were included. Methodological quality was assessed using guidelines from the Centre for Reviews and Dissemination. RESULTS: Eleven studies, including predominately males were included (n...... and knee extensor muscle weakness are risk factors for osteoarthritis these results highlight the clinical importance of addressing muscle weakness in these individuals. This article is protected by copyright. All rights reserved....

  8. Intermuscular interaction via myofascial force transmission: Effects of tibialis anterior and extensor digitorum longus length on force transmission from rat extensor digitorum longus muscle

    NARCIS (Netherlands)

    Maas, Huub; Baan, Guus C.; Huijing, P.A.J.B.M.

    2001-01-01

    Force transmission in rat anterior crural compartment, containing tibialis anterior (TA), extensor hallucis longus (EHL) and extensor digitorum longus (EDL) muscles, was investigated. These muscles together with the muscles of the peroneal compartment were excited maximally. Force was measured at

  9. Elbow flexor and extensor muscle weakness in lateral epicondylalgia.

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    Coombes, Brooke K; Bisset, Leanne; Vicenzino, Bill

    2012-05-01

    To evaluate whether deficits of elbow flexor and extensor muscle strength exist in lateral epicondylalgia (LE) in comparison with a healthy control population. Cross-sectional study. 150 participants with unilateral LE were compared with 54 healthy control participants. Maximal isometric elbow flexion and extension strength were measured bilaterally using a purpose-built standing frame such that gripping was avoided. The authors found significant side differences in elbow extensor (-6.54 N, 95% CI -11.43 to -1.65, p=0.008, standardised mean difference (SMD) -0.45) and flexor muscle strength (-11.26 N, 95% CI -19.59 to -2.94, p=0.009, SMD -0.46) between LE and control groups. Within the LE group, only elbow extensor muscle strength deficits between sides was significant (affected-unaffected: -2.94 N, 95% CI -5.44 to -0.44). Small significant deficits of elbow extensor and flexor muscle strength exist in the affected arm of unilateral LE in comparison with healthy controls. Notably, comparing elbow strength between the affected and unaffected sides in unilateral epicondylalgia is likely to underestimate these deficits. Trial Registration Australian New Zealand Clinical Trials Register ACTRN12609000051246.

  10. Measurement of fatigue in knee flexor and extensor muscles.

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    Kawabata, Y; Senda, M; Oka, T; Yagata, Y; Takahara, Y; Nagashima, H; Inoue, H

    2000-04-01

    In order to examine fatigue of the knee flexor and extensor muscles and to investigate the characteristics of muscular fatigue in different sports, a Cybex machine was used to measure muscle fatigue and recovery during isokinetic knee flexion and extension. Eighteen baseball players, 12 soccer players and 13 marathon runners were studied. Each subject was tested in the sitting position and made to perform 50 consecutive right knee bends and stretches at maximum strength. This was done 3 times with an interval of 10 min between each series. The peak torque to body weight ratio and the fatigue rate were determined in each case. In all subjects, the peak torque to body weight ratio was higher for extensors than flexors. Over the 3 trials, the fatigue rate of extensors showed little change, while that of flexors had a tendency to increase. In each subject, knee extensors showed a high fatigue rate but a quick recovery, while knee flexors showed a low fatigue rate but a slow recovery. As the marathon runners had the smallest fatigue rates for both flexors and extensors, we concluded that marathon runners had more stamina than baseball players and soccer players.

  11. An anomalous accessory extensor proprius indicis muscle: A case report

    Directory of Open Access Journals (Sweden)

    Mustafa Kurklu

    2013-12-01

    Full Text Available Variations related to tendon insertion and musculotendinous junction of the extensor proprius indicis muscle are commonly encountered. An anomalous extensor indicis proprius muscle (EIP tendon was detected in a fifty-year-old female cadaver during routine dissection of the right upper extremity. The body of tendon was initiated from the posterior ulna as a one muscle body, then continued as two separate muscle bodies and tendons and finally they were separated into two slips after passing the fourth dorsal compartment. As a radial part, it was divided into two slips at the level of the first metacarpophalangeal joint, and conjugated with the extensor pollicis longus (EPL muscle. Then, as an ulnar part, it was terminated at the radial side of the lateral band of the second metacarpophalangeal joint. Familiarity with the normal anatomy and variations of the tendons may help to prevent confusion and mistakes during tendon repairs, and tendon transfers. [Hand Microsurg 2013; 2(3.000: 122-124

  12. Neck extensor muscle weakness (Dropped head syndrome) following radiotherapy

    International Nuclear Information System (INIS)

    Bhatia, S.; Miller, R.C.; Lachance, D.L.

    2006-01-01

    Background. Dropped head syndrome is an unusual condition in which the head cannot be held upright in its normal anatomic position secondary to pronounced, isolated, neck extensor muscle weakness. Case report. A case of dropped head syndrome in a female with a history of radiotherapy for Hodgkin's lymphoma and a clinical history consistent with multiple sclerosis is presented, and potential etiologies are discussed. Conclusions. Muscular atrophy and lower motor neuron injury secondary to isolated anterior horn cell injury from radiotherapy emerge as the most likely etiology. (author)

  13. The Effects of High-Intensity versus Low-Intensity Resistance Training on Leg Extensor Power and Recovery of Knee Function after ACL-Reconstruction

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    Theresa Bieler

    2014-01-01

    Full Text Available Objective. Persistent weakness is a common problem after anterior cruciate ligament- (ACL- reconstruction. This study investigated the effects of high-intensity (HRT versus low-intensity (LRT resistance training on leg extensor power and recovery of knee function after ACL-reconstruction. Methods. 31 males and 19 females were randomized to HRT (n=24 or LRT (n=26 from week 8–20 after ACL-reconstruction. Leg extensor power, joint laxity, and self-reported knee function were measured before and 7, 14, and 20 weeks after surgery. Hop tests were assessed before and after 20 weeks. Results. Power in the injured leg was 90% (95% CI 86–94% of the noninjured leg, decreasing to 64% (95% CI 60–69% 7 weeks after surgery. During the resistance training phase there was a significant group by time interaction for power (P=0.020. Power was regained more with HRT compared to LRT at week 14 (84% versus 73% of noninjured leg, resp.; P=0.027 and at week 20 (98% versus 83% of noninjured leg, resp.; P=0.006 without adverse effects on joint laxity. No other between-group differences were found. Conclusion. High-intensity resistance training during rehabilitation after ACL-reconstruction can improve muscle power without adverse effects on joint laxity.

  14. ''Dropped-head'' syndrome due to isolated myositis of neck extensor muscles: MRI findings

    International Nuclear Information System (INIS)

    Gaeta, Michele; Mazziotti, Silvio; Blandino, Alfredo; Toscano, Antonio; Rodolico, Carmelo; Mazzeo, Anna

    2006-01-01

    MRI findings of a patient with dropped-head syndrome due to focal myositis of the neck extensor muscles are presented. MRI showed oedematous changes and marked enhancement of the neck extensor muscles. After therapy MRI demonstrated disappearance of the abnormal findings. (orig.)

  15. The variation of the strength of neck extensor muscles and semispinalis capitis muscle size with head and neck position.

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    Rezasoltani, A; Nasiri, R; Faizei, A M; Zaafari, G; Mirshahvelayati, A S; Bakhshidarabad, L

    2013-04-01

    Semispinalis capitis muscle (SECM) is a massive and long cervico-thoracic muscle which functions as a main head and neck extensor muscle. The aim of this study was to detect the effect of head and neck positions on the strength of neck extensor muscles and size of SECM in healthy subjects. Thirty healthy women students voluntarily participated in this study. An ultrasonography apparatus (Hitachi EUB 525) and a system of tension-meter were used to scan the right SECM at the level of third cervical spine and to measure the strength of neck extensor muscles at three head and neck positions. Neck extensor muscles were stronger in neutral than flexion or than extension positions while the size of SECM was larger in extension than neutral or than flexion position. The force generation capacity of the main neck extensor muscle was lower at two head and neck flexion and extension positions than neutral position. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Investigation Of Wrist Flexor/Extensor Muscle Strength Following Arthroscopic Surgical Treatment Of Lateral Epicondylitis

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    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.

  17. The influence of fat infiltration of back extensor muscles on osteoporotic vertebral fractures.

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    So, Kwang-Young; Kim, Dae-Hee; Choi, Dong-Hyuk; Kim, Choong-Young; Kim, Jeong-Seok; Choi, Yong-Soo

    2013-12-01

    Retrospective study. To investigate the influence of fat infiltration at low back extensor muscles on osteoporotic vertebral fracture. In persons with stronger back muscles, the risk of osteoporotic vertebral fractures will likely be lower than in those persons with weaker back muscles. However, the degree of influence of fat infiltration of the back extensor muscle on osteoporotic vertebral fracture remains controversial. Two hundred and thirty-seven patients who had undergone lumbar spine magnetic resonance imaging and bone mineral density (BMD) were enrolled in this study. The amount of low back extensor muscle was determined using the pseudocoloring technique on an axial view of the L3 level. The patients were divided into two groups: osteoporotic vertebral fracture group (group A) and non-fracture group (group B). The amount of low back extensor muscle is compared with BMD, degenerative change of disc, osteophyte grade of facet joint and promontory angle to reveal the association between these factors. A negative correlation is found between age and the amount of low back extensor muscle (p=0.001). The amount of low back extensor muscle in group A and group B was 60.3%±14.5% and 64.2%±9.3% respectively, thus showing a significantly smaller amount of low back extensor muscle in the osteoporotic vertebral fracture group (p=0.015). Fat infiltration of low back extensor muscle was increased in osteoporotic vertebral fracture patients. Therefore, fat infiltration of low back extensor muscle in an elderly person may be a risk factor of osteoporotic vertebral fracture.

  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. Myostatin dysfunction impairs force generation in extensor digitorum longus muscle and increases exercise-induced protein efflux from extensor digitorum longus and soleus muscles.

    Science.gov (United States)

    Baltusnikas, Juozas; Kilikevicius, Audrius; Venckunas, Tomas; Fokin, Andrej; Bünger, Lutz; Lionikas, Arimantas; Ratkevicius, Aivaras

    2015-08-01

    Myostatin dysfunction promotes muscle hypertrophy, which can complicate assessment of muscle properties. We examined force generating capacity and creatine kinase (CK) efflux from skeletal muscles of young mice before they reach adult body and muscle size. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of Berlin high (BEH) mice with dysfunctional myostatin, i.e., homozygous for inactivating myostatin mutation, and with a wild-type myostatin (BEH+/+) were studied. The muscles of BEH mice showed faster (P myostatin dysfunction leads to impairment in muscle force generating capacity in EDL and increases susceptibility of SOL and EDL to protein loss after exercise.

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

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    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. Knee extensor muscle weakness is a risk factor for development of knee osteoarthritis

    DEFF Research Database (Denmark)

    Oiestad, B E; Juhl, C B; Eitzen, I

    2015-01-01

    The objective of this study was to perform a systematic review and meta-analysis on the association between knee extensor muscle weakness and the risk of developing knee osteoarthritis. A systematic review and meta-analysis was conducted with literature searches in Medline, SPORTDiscus, EMBASE......, CINAHL, and AMED. Eligible studies had to include participants with no radiographic or symptomatic knee osteoarthritis at baseline; have a follow-up time of a minimum of 2 years, and include a measure of knee extensor muscle strength. Hierarchies for extracting data on knee osteoarthritis and knee...... extensor muscle strength were defined prior to data extraction. Meta-analysis was applied on the basis of the odds ratios (ORs) of developing symptomatic knee osteoarthritis or radiographic knee osteoarthritis in subjects with knee extensor muscle weakness. ORs for knee osteoarthritis and 95% confidence...

  2. Measurement of maximal isometric torque and muscle quality of the knee extensors and flexors in healthy 50- to 70-year-old women.

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    Francis, Peter; Toomey, Clodagh; Mc Cormack, William; Lyons, Mark; Jakeman, Philip

    2017-07-01

    Muscle quality is defined as strength per unit muscle mass. The aim of this study was to measure the maximal voluntary isometric torque of the knee extensor and flexor muscle groups in healthy older women and to develop an index of muscle quality based on the combined knee extensor and flexor torque per unit lean tissue mass (LTM) of the upper leg. One hundred and thirty-six healthy 50- to 70-year-old women completed an initial measurement of isometric peak torque of the knee extensors and flexors (Con-Trex MJ; CMV AG, Dubendorf, Switzerland) that was repeated 7 days later. Subsequently, 131 women returned for whole- and regional-body composition analysis (iDXA ™ ; GE Healthcare, Chalfont St Giles, Buckinghamshire, UK). Isometric peak torque demonstrated excellent within-assessment reliability for both the knee extensors and flexors (ICC range: 0·991-1·000). Test-retest reliability was lower (ICC range: 0·777-0·828) with an observed mean increase of 5% in peak torque [6·2 (17·2) N m] on the second day of assessment (Ptorque (-12·2%; P = 0·001) was double that of the relative, non-significant, median difference in upper leg LTM (-5·3%; P = 0·102) between those in the 5th and 6th decade. The majority of difference in peak isometric torque came from the knee extensors (15·1 N m, Ptorque normalized for upper leg LTM (muscle quality) was 8% lower between decades (P = 0·029). These findings suggest strength per unit tissue may provide a better indication of age-related differences in muscle quality prior to change in LTM. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  3. The influence of lumbar extensor muscle fatigue on lumbar-pelvic coordination during weightlifting.

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    Hu, Boyi; Ning, Xiaopeng

    2015-01-01

    Lumbar muscle fatigue is a potential risk factor for the development of low back pain. In this study, we investigated the influence of lumbar extensor muscle fatigue on lumbar-pelvic coordination patterns during weightlifting. Each of the 15 male subjects performed five repetitions of weightlifting tasks both before and after a lumbar extensor muscle fatiguing protocol. Lumbar muscle electromyography was collected to assess fatigue. Trunk kinematics was recorded to calculate lumbar-pelvic continuous relative phase (CRP) and CRP variability. Results showed that fatigue significantly reduced the average lumbar-pelvic CRP value (from 0.33 to 0.29 rad) during weightlifting. The average CRP variability reduced from 0.17 to 0.15 rad, yet this change ws statistically not significant. Further analyses also discovered elevated spinal loading during weightlifting after the development of lumbar extensor muscle fatigue. Our results suggest that frequently experienced lumbar extensor muscle fatigue should be avoided in an occupational environment. Lumbar extensor muscle fatigue generates more in-phase lumbar-pelvic coordination patterns and elevated spinal loading during lifting. Such increase in spinal loading may indicate higher risk of back injury. Our results suggest that frequently experienced lumbar muscle fatigue should be avoided to reduce the risk of LBP.

  4. Function and structure of the deep cervical extensor muscles in patients with neck pain.

    Science.gov (United States)

    Schomacher, Jochen; Falla, Deborah

    2013-10-01

    The deep cervical extensors are anatomically able to control segmental movements of the cervical spine in concert with the deep cervical flexors. Several investigations have confirmed changes in cervical flexor muscle control in patients with neck pain and as a result, effective evidence-based therapeutic exercises have been developed to address such dysfunctions. However, knowledge on how the deep extensor muscles behave in patients with neck pain disorders is scare. Structural changes such as higher concentration of fat within the muscle, variable cross-sectional area and higher proportions of type II fibres have been observed in the deep cervical extensors of patients with neck pain compared to healthy controls. These findings suggest that the behaviour of the deep extensors may be altered in patients with neck pain. Consistent with this hypothesis, a recent series of studies confirm that patients display reduced activation of the deep cervical extensors as well as less defined activation patterns. This article provides an overview of the various different structural and functional changes in the deep neck extensor muscles documented in patients with neck pain. Relevant recommendations for the management of muscle dysfunction in patients with neck pain are presented. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Anatomical variation of radial wrist extensor muscles: a study in cadavers

    Directory of Open Access Journals (Sweden)

    Soubhagya Ranjan Nayak

    2008-01-01

    Full Text Available OBJECTIVE: The tendons of the extensor carpi radialis longus and brevis muscles are quite useful in tendon transfer, such as in correction of finger clawing and restoration of thumb opposition. Knowledge of additional radial wrist extensor muscle bellies with independent tendons is useful in the above-mentioned surgical procedures. METHODS: The skin, subcutaneous tissue, and antebrachial fascia of 48 (24 on the right side and 24 on left side male upper limb forearms were dissected. The following aspects were then analyzed: (a the presence of additional muscle bellies of radial wrist extensors, (b the origin and insertion of the additional muscle, and (c measurements of the muscle bellies and their tendons. RESULTS: Five out of 48 upper limbs (10.41% had additional radial wrist extensors; this occurred in 3 out of 24 left upper limbs (12.5% and 2 out of 24 right upper limbs (8.3%. In one of the right upper limbs, two additional muscles were found. The length and width of each additional muscle belly and its tendon ranged between 2 - 15cm by 0.35 - 6.4cm and 2.8 - 20.8cm by 0.2 0.5cm, respectively. The additional radial wrist extensor tendons in our study basically originated either from the extensor carpi radialis longus or brevis muscles and were inserted at the base of the 2nd or 3rd metacarpal bone. CONCLUSION: The present study will inform surgeons about the different varieties of additional radial wrist extensors and the frequency of their occurrence.

  6. Net joint moments and muscle activation in barbell squats without and with restricted anterior leg rotation.

    Science.gov (United States)

    Chiu, Loren Z F; vonGaza, Gabriella L; Jean, Liane M Y

    2017-01-01

    Muscle utilisation in squat exercise depends on technique. The purpose of this study was to compare net joint moments (NJMs) and muscle activation during squats without and with restricted leg dorsiflexion. Experienced men (n = 5) and women (n = 4) performed full squats at 80% one repetition maximum. 3D motion analysis, force platform and (EMG) data were collected. Restricting anterior leg rotation reduced anterior leg (P = 0.001) and posterior thigh (P squat depth, ankle plantar flexor (P squats. Hip extensor NJM (P = 0.14) was not different between squat types at maximum squat depth. Vastus lateralis (P > 0.05), vastus medialis (P > 0.05) and rectus femoris (P > 0.05) EMG were not different between squat types. Unrestricted squats have higher ankle plantar flexor and knee extensor NJM than previously reported from jumping and landing. However, ankle plantar flexor and knee extensor NJM are lower in restricted squats than previous studies of jumping and landing. The high NJM in unrestricted squat exercise performed through a full range of motion suggests this squat type would be more effective to stimulate adaptations in the lower extremity musculature than restricted squats.

  7. ''Dropped-head'' syndrome due to isolated myositis of neck extensor muscles: MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Gaeta, Michele; Mazziotti, Silvio; Blandino, Alfredo [University of Messina, Department of Radiological Sciences, Messina (Italy); Toscano, Antonio; Rodolico, Carmelo; Mazzeo, Anna [University of Messina, Department of Neurosciences, Psychiatry and Anaesthesiology, Messina (Italy)

    2006-02-15

    MRI findings of a patient with dropped-head syndrome due to focal myositis of the neck extensor muscles are presented. MRI showed oedematous changes and marked enhancement of the neck extensor muscles. After therapy MRI demonstrated disappearance of the abnormal findings. (orig.)

  8. Low-level activity of the trunk extensor muscles causes electromyographic manifestations of fatigue in absence of decreased oxygenation

    NARCIS (Netherlands)

    Dieën, J.H. van; Westebring van der; Putten, E.P.; Kingma, I.; Looze, M.P. de

    2009-01-01

    This study was designed to determine whether trunk extensor fatigue occurs during low-level activity and whether this is associated with a drop in muscle tissue oxygenation. Electromyography (EMG) feedback was used to impose constant activity in a part of the trunk extensor muscles. We hypothesized

  9. Early-onset dropped head syndrome after radiotherapy for head and neck cancer: dose constraints for neck extensor muscles

    International Nuclear Information System (INIS)

    Inaba, Koji; Nakamura, Satoshi; Okamoto, Hiroyuki; Kashihara, Tairo; Kobayashi, Kazuma; Harada, Ken; Kitaguchi, Mayuka; Sekii, Shuhei; Takahashi, Kana; Murakami, Naoya; Ito, Yoshinori; Igaki, Hiroshi; Uno, Takashi; Itami, Jun

    2016-01-01

    Dropped head syndrome (DHS) is a famous but unusual late complication of multimodality treatment for head and neck carcinoma. We reported this early-onset complication and analyzed the dose to the neck extensor muscles. We examined the records of three patients with DHS after radiotherapy. The doses to the neck extensor muscles were compared between three patients with DHS and nine patients without DHS. The mean dose to the neck extensor muscles of the three patients with DHS were 58.5 Gy, 42.3 Gy and 60.9 Gy, while the dose was <50 Gy in all nine patients in the control group. The onset of this syndrome was 5 months, 6 months and 15 months. The early-onset DHS may have something to do with dose to the neck extensor muscles. The proposed dose to the neck extensor muscles might be <46 Gy (or at least <50 Gy)

  10. 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.

  11. [Fall risk assessment and knee extensor muscle activity in elderly people].

    Science.gov (United States)

    Oya, Yukiko; Nakamura, Masumi; Tabata, Emi; Morizono, Ryo; Mori, Sachiko; Kimuro, Yukari; Horikawa, Etsuo

    2008-05-01

    The purpose of this study was to analyze relationships between the history of falls, tripping, sway, and knee extensor muscle strengths as a tool for fall risk assessment in elderly people. We examined effective fall prevention measures. We investigated 102 elderly volunteers in the community. The subjects were classified according to history of falls, tripping, sway and 5 performance tests conducted to assess fall risk including Timed up-and-go test (TUG), Functional Reach test (FR), Hand grip and Reaction time (RT). In addition, the time serial data of the knee extensor muscle strength were acquired using a hand-held dynamometer. In comparison to the non-faller group, the faller group showed a significantly higher incident rate of tripping and sway. A frequency analysis using the Maximum Entropy Method revealed that the fallers group showed lower peak frequency (p=0.025). Also, the slope of the logarithmical spectrum was less steep in the fallers group (p=0.035). Also results from analysis of the peak force latency from the beginning of measurement to 50%, 80%, and 100% muscle strength, also showed that the faller group took more time for maximal voluntary contraction. The frequency analysis of the time series date of peak force latency of knee extensor muscle strength revealed that the muscle activity differs in faller compared to non-fallers. This study suggested that knee extensor muscle isometric performance could possibly be used as a new tool for fall risk assessment. We concluded that exercises to raise maximal muscle strength and muscle response speed are useful for the prevention of falls.

  12. The Reliability of Isometer 2 Device in Measuring of Cervical Flexor and Extensor Muscles Strength

    Directory of Open Access Journals (Sweden)

    Asghar Reza Soltan-Zadeh

    2006-07-01

    Full Text Available Objective: The strength of a group of muscles can be measured by muscle strength test, employing a force measuring instrument. In order to monitor the effectiveness of a therapeutic or training programs we need a reliable technique which is also accurate in repeated measurements. The purpose of this study was to examine the reliability of an isometric neck muscle force measurement device.  Materials & Methods: Thirty seven healthy non athlete subjects (18 males and 19 females, aged 18-25 participated in this analytical study. The maximal isometric contractions of the neck extensor and flexor muscles were measured in different times and different days and by two different testers. A new sensitive “load cell” was applied to our previously designed neck muscle force measurement apparatus. Results: The results of the inter-trail, test retest, and inter rater reliability (0.86 < ICC < 0.98 , 2.2< Sw <5.1 N indicated that the neck muscle force measurements were highly repeatable and less variable between measurements. There were no statistically significant differences in neck muscle force measurements, between times, between days and between retsters. Maximum isometric contractions were significantly higher in males than in the females (p < 0.001. Women’s neck muscle strengths were 30.8% and 46.1% of men in cervical extension and cervical flexion. Conclusion: In this study we used a new model (Isometer 2 of our previous apparatus (Isometer. The isometric strength of neck flexor and extensor muscles which was measured by Isometer 2 appeared to be a reliable and useful method for measuring the force of the neck extensor and flexor muscles.

  13. 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.

  14. Electromyographic analysis of the vertebral extensor muscles during the Biering-Sorensen Test

    Directory of Open Access Journals (Sweden)

    Ligia Moreira de Santana

    2014-03-01

    Full Text Available The purpose of the study was to analyze the electromyographic signal of the multifidus, longissimus thoracis and the lumbar iliocostalis muscles during the Biering-Sorensen test in subjects without lower back pain. Twenty volunteers performed the test on three separate occasions. An analysis of variance detected a difference between the three test times (p = 0.0026. For the frequency domain, it was observed that there were differences between the multifidus and the lumbar erectors muscles; longissimus and iliocostalis muscles. However, in the time domain analysis, no difference was observed. As the values of the slope coefficients of median frequencies were higher for the multifidus muscle, compared to the longissimus and lumbar iliocostalis muscles, this may indicate a higher tendency toward muscle fatigue. Therefore, considering the applied methodology, the study of electromyographic signals in the frequency domain should be considered as an instrument to assess fatigue of the spinal extensor muscles in clinical situations.

  15. Myofascial force transmission causes interaction between adjacent muscles and connective tissue: Effects of blunt dissection and compartmental fasciotomy on length force characteristics of rat extensor digitorum longus muscle

    NARCIS (Netherlands)

    Huijing, P.A.J.B.M.; Baan, G.C.

    2001-01-01

    Muscles within the anterior tibial compartment (extensor digitorum longus: EDL. tibialis anterior: TA, and extensor hallucis longus muscles: EHL) and within the peroneal compartment were excited simultaneously and maximally. The ankle joint was fixed kept at 90°. For EDL length force characteristics

  16. Muscle power is an important measure to detect deficits in muscle function in hip osteoarthritis: a cross-sectional study.

    Science.gov (United States)

    Bieler, Theresa; Magnusson, Stig Peter; Christensen, Helle Elisabeth; Kjaer, Michael; Beyer, Nina

    2017-07-01

    To investigate between-leg differences in hip and thigh muscle strength and leg extensor power in patients with unilateral hip osteoarthritis. Further, to compare between-leg differences in knee extensor strength and leg extensor power between patients and healthy peers. Seventy-two patients (60-87 years) with radiographic and symptomatic hip osteoarthritis not awaiting hip replacement and 35 healthy peers (63-82 years) were included. Hip and thigh muscle strength and leg extensor power were measured in patients and knee extensor strength and leg extensor power in healthy. The symptomatic extremity in patients was significantly (p hip muscles (8-17%), knee extensors (11%) and leg extensor power (19%). Healthy older adults had asymmetry in knee extensor strength (6%, p hip osteoarthritis. Implications for Rehabilitation Even in patients with mild symptoms not awaiting hip replacement a generalized muscle weakening of the symptomatic lower extremity seems to be present. Between-leg differences in leg extensor power (force × velocity) appears to be relatively large (19%) in patients with unilateral hip osteoarthritis in contrast to healthy peers who show no asymmetry. Compared to muscle strength the relationship between functional performance and leg extensor power seems to be stronger, and more strongly related to power of the symptomatic lower extremity. Our results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with mild symptoms not awaiting hip replacement.

  17. Are fatigue-related EMG-parameters correlated to trunk extensor muscles fatigue induced by the Sörensen test?

    OpenAIRE

    Demoulin Christophe; George, Florian; Matheve, Thomas; Jidovtseff, Boris; Vanderthommen, Marc

    2016-01-01

    The Sorensen test has been extensively studied and is a rapid, simple, and reproducible evaluation of the trunk extensor muscles [1]. It is often considered as a fatigue test because fatigue-related electromyographic (EMG) parameters change throughout the test [2]; however, only recently it has been confirmed that this test induces a decrease of trunk extensor force during a maximal voluntary contraction (MVC) [3], which best characterises muscle fatigue. The main aim of this stud...

  18. Impact of Fat Infiltration in Cervical Extensor Muscles on Cervical Lordosis and Neck Pain: A Cross-Sectional Study.

    Science.gov (United States)

    Kim, Choong-Young; Lee, Sang-Min; Lim, Seong-An; Choi, Yong-Soo

    2018-06-01

    Weakness of cervical extensor muscles causes loss of cervical lordosis, which could also cause neck pain. The aim of this study was to investigate the impact of fat infiltration in cervical extensor muscles on cervical lordosis and neck pain. Fifty-six patients who suffered from neck pain were included in this study. Fat infiltration in cervical extensor muscles was measured at each level of C2-3 and C6-7 using axial magnetic resonance imaging. The visual analogue scale (VAS), 12-Item Short Form Health Survey (SF-12), and Neck Disability Index (NDI) were used for clinical assessment. The mean fat infiltration was 206.3 mm 2 (20.3%) at C2-3 and 240.6 mm 2 (19.5%) at C6-7. Fat infiltration in cervical extensor muscles was associated with high VAS scores at both levels ( p = 0.047 at C2-3; p = 0.009 at C6-7). At C2-3, there was a negative correlation between fat infiltration of the cervical extensor muscles and cervical lordosis (r = -0.216; p = 0.020). At C6-7, fat infiltration in the cervical extensor muscles was closely related to NDI ( p = 0.003) and SF-12 ( p > 0.05). However, there was no significant correlation between cervical lordosis and clinical outcomes (VAS, p = 0.112; NDI, p = 0.087; and SF-12, p > 0.05). These results suggest that fat infiltration in the upper cervical extensor muscles has relevance to the loss of cervical lordosis, whereas fat infiltration in the lower cervical extensor muscles is associated with cervical functional disability.

  19. 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.

  20. The effect of age and unilateral leg immobilization for 2 weeks on substrate utilization during moderate intensity exercise in human skeletal muscle

    DEFF Research Database (Denmark)

    Vigelsø, Andreas; Gram, Martin; Dybboe, Rie

    2016-01-01

    in older than in young men, and while young men demonstrated net leg glycerol release during exercise, older men showed net glycerol uptake. At baseline, IMTG, muscle pyruvate dehydrogenase complex activity, protein content of adipose triglyceride lipase (ATGL), acetyl-CoA carboxylase 2, AMP-activated......; 23 ± 1 years) and older (n = 15; 68 ± 1 years) men, while the contralateral leg served as control. After immobilization, the participants performed two-legged isolated knee-extensor exercise at 20 ± 1 Watt (∼50% Wattmax ) for 45 min with catheters inserted in the brachial artery and both femoral...... veins. Biopsy samples obtained from vastus lateralis muscles of both legs before and after exercise were used for analysis of substrates, protein content and enzyme activities. During exercise, leg substrate utilization (RQ) did not differ between groups or legs. Leg fatty acid (FA) uptake was greater...

  1. The Effects of High-Intensity versus Low-Intensity Resistance Training on Leg Extensor Power and Recovery of Knee Function after ACL-Reconstruction

    DEFF Research Database (Denmark)

    Bieler, Theresa; Sobol, Nanna Aue; Andersen, Lars L

    2014-01-01

    OBJECTIVE: Persistent weakness is a common problem after anterior cruciate ligament- (ACL-) reconstruction. This study investigated the effects of high-intensity (HRT) versus low-intensity (LRT) resistance training on leg extensor power and recovery of knee function after ACL-reconstruction. METH...

  2. Proximal forearm extensor muscle strain is reduced when driving nails using a shock-controlled hammer.

    Science.gov (United States)

    Buchanan, Kimberly A; Maza, Maria; Pérez-Vázquez, Carlos E; Yen, Thomas Y; Kijowski, Richard; Liu, Fang; Radwin, Robert G

    2016-10-01

    Repetitive hammer use has been associated with strain and musculoskeletal injuries. This study investigated if using a shock-control hammer reduces forearm muscle strain by observing adverse physiological responses (i.e. inflammation and localized edema) after use. Three matched framing hammers were studied, including a wood-handle, steel-handle, and shock-control hammer. Fifty volunteers were randomly assigned to use one of these hammers at a fatiguing pace of one strike every second, to seat 20 nails in a wood beam. Magnetic resonance imaging was used to scan the forearm muscles for inflammation before the task, immediately after hammering, and one to two days after. Electromyogram signals were measured to estimate grip exertions and localized muscle fatigue. High-speed video was used to calculate the energy of nail strikes. While estimated grip force was similar across the three hammers, the shock-control hammer had 40% greater kinetic energy upon impact and markedly less proximal extensor muscle edema than the wood-handle and steel-handle hammers, immediately after use (phandle shock can mitigate strain in proximal forearm extensor muscles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Anomalous bilateral contribution of extensor pollicis longus and muscle fusion of the first compartment of the wrist

    Directory of Open Access Journals (Sweden)

    Rodrigo César Rosa

    2016-04-01

    Full Text Available Knowledge of the anatomical variations of the muscles of the first dorsal compartments of the wrist is clinically relevant to De Quervain's tenosynovitis and to reconstructive surgeries. In the literature, there are many reports of the presence of multiple insertion tendons in the first dorsal compartment of the wrist, but few reports describe occurrences of fusion and muscle contributions. This case report describes an anomalous bilateral contribution of the extensor pollicis longus. This anomalous contribution was found through a slender auxiliary tendon that crossed laterally under the extensor retinaculum, entered the first dorsal compartment of the wrist and merged with the tendon of the extensor pollicis brevis muscle. In the same cadaver in which this contribution was present, there was atypical muscle fusion of the abductor pollicis longus muscle and extensor pollicis brevis muscle. In conclusion, anomalous bilateral contribution of the extensor pollicis longus muscle and atypical muscle fusion, concomitant with a variant insertion pattern, are the highlight of this case report. Furthermore, it is concluded that additional tendons may be effectively used in reconstructive surgeries, but that there is a need for knowledge of the possible numerical and positional variations of these tendons, with a view to making more effective surgical plans.

  4. Sex comparisons of non-local muscle fatigue in human elbow flexors and knee extensors

    Science.gov (United States)

    Ye, Xin; Beck, Travis W.; Wages, Nathan P.; Carr, Joshua C.

    2018-01-01

    Objectives: To examine non-local muscle fatigue (NLMF) in both contralateral homologous and non-related heterogonous muscles for both sexes. Methods: Ten men and nine women participated in this study. After the familiarization visit, subjects completed four separate randomly sequenced experimental visits, during which the fatiguing interventions (six sets of 30-second maximal isometric contractions) were performed on either their right elbow flexors or knee extensors. Before (Pre-) and after (Post-) the fatiguing interventions, the isometric strength and the corresponding surface electromyographic (EMG) amplitude were measured for the non-exercised left elbow flexors or knee extensors. Results: For the non-exercised elbow flexors, the isometric strength decreased for both sexes (sex combined mean±SE: Pre vs. Post=339.67±18.02 N vs. 314.41±16.37 N; pisometric knee extension strength for men (Pre vs. Post =845.02±66.26 N vs. 817.39±67.64 N; p=0.019), but not for women. Conclusions: The presence of NMLF can be affected by factors such as sex and muscle being tested. Women are less likely to demonstrate NLMF in lower body muscle groups. PMID:29504584

  5. Lumbar extensor muscle force control is associated with disability in people with chronic low back pain.

    Science.gov (United States)

    Pranata, Adrian; Perraton, Luke; El-Ansary, Doa; Clark, Ross; Fortin, Karine; Dettmann, Tim; Brandham, Robert; Bryant, Adam

    2017-07-01

    The ability to control lumbar extensor force output is necessary for daily activities. However, it is unknown whether this ability is impaired in chronic low back pain patients. Similarly, it is unknown whether lumbar extensor force control is related to the disability levels of chronic low back pain patients. Thirty-three chronic low back pain and 20 healthy people performed lumbar extension force-matching task where they increased and decreased their force output to match a variable target force within 20%-50% maximal voluntary isometric contraction. Force control was quantified as the root-mean-square-error between participants' force output and target force across the entire, during the increasing and decreasing portions of the force curve. Within- and between-group differences in force-matching error and the relationship between back pain group's force-matching results and their Oswestry Disability Index scores were assessed using ANCOVA and linear regression respectively. Back pain group demonstrated more overall force-matching error (mean difference=1.60 [0.78, 2.43], Pback pain group demonstrated more force-matching error while increasing than decreasing force output (mean difference=1.74, Pback pain group (R 2 =0.19, P=0.006). Lumbar extensor muscle force control is compromised in chronic low back pain patients. Force-matching error predicts disability, confirming the validity of our force control protocol for chronic low back pain patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Catalase-positive microperoxisomes in rat soleus and extensor digitorum longus muscle fiber types

    Science.gov (United States)

    Riley, Danny A.; Bain, James L. W.; Ellis, Stanley

    1988-01-01

    The size, distribution, and content of catalase-reactive microperoxisomes were investigated cytochemically in three types of muscle fibers from the soleus and the extensor digitorum longus (EDL) of male rats. Muscle fibers were classified on the basis of the mitochondrial content and distribution, the Z-band widths, and the size and shape of myofibrils as the slow-twitch oxidative (SO), the fast-twitch oxidative glycolytic (FOG), and the fast-twitch glycolytic (FG) fibers. It was found that both the EDL and soleus SO fibers possessed the largest microperoxisomes. A comparison of microperoxisome number per muscle fiber area or the microperoxisome area per fiber area revealed following ranking, starting from the largest number and the area-ratio values: soleus SO, EDL SO, EDL FOG, and EDL FG.

  7. Variant Branching Pattern of Dorsalis Pedis Artery Accompanied with Anomalous Presence of Extensor Hallucis Brevis Muscle

    Directory of Open Access Journals (Sweden)

    Ashwini Aithal Padur

    2017-10-01

    Full Text Available During routine dissection, we came across multiple variations in the dorsum of the right foot. Dorsalis pedis artery (DPA presented with an unusual branching pattern. The arcuate artery was completely absent, and hence three tarsal branches arose from lateral side of DPA. The first branch continued as first dorsal metatarsal artery, the second branch continued as the second dorsal metatarsal artery, and the third branch continued as third dorsal metatarsal artery which also provided a small twig to the fourth intermetatarsal space as the fourth dorsal metatarsal artery. We also observed the unique presence of extensor hallucis brevis muscle with the origin from the medial part of superior surface of the calcaneus and inserted to proximal phalanx of great toe. Since the DPA was just beneath this muscle, anomalous presence of the muscle may lead to compression of DPA. Awareness regarding such variations is critical for angiographers, vascular surgeons, reconstructive and plastic surgeons.

  8. Reconstruction of long digital extensor tendon by cranial tibial muscle fascia graft in a dog.

    Science.gov (United States)

    Sabiza, Soroush; Khajeh, Ahmad; Naddaf, Hadi

    2016-01-01

    Tendon rupture in dogs is generally the result of a direct trauma. This report described the use of adjacent muscle autogenic fascial graft for reconstruction of distal rupture of long digital extensor tendon in a dog. A two-year-old male mix breed dog, was presented with a non-weight bearing lameness of the right hind limb and a deep rupture of lateral side of right tarsus. History taking revealed that this rupture appeared without any apparent cause, when walking around the farm, three days before. Radiography was done and no fracture was observed. Hyperextension of right tarsal joint compared to left limb was observed. Under general anesthesia, after dissections of the ruptured area, complete rupture of long digital extensor tendon was revealed. Then, we attempted to locate the edge of the tendon, however, the tendon length was shortened approximately 1 cm. Hence, a strip of 1 cm length from fascia of cranial tibial muscle was harvested to fill the defect. The graft was sutured to the two ends of tendon using locking loop pattern. Subcutaneous layers and the skin were sutured routinely. Ehmer sling bandage was applied to prevent weight bearing on the surgical region. Re-examination and phone contact with the owner eight weeks and six months postoperatively revealed a poor lameness and excellent function of the dog, respectively. It could be concluded that the fascia of adjacent muscles can be used as an autogenic graft for reconstruction of some tendon ruptures.

  9. The minimum sit-to-stand height test: reliability, responsiveness and relationship to leg muscle strength.

    Science.gov (United States)

    Schurr, Karl; Sherrington, Catherine; Wallbank, Geraldine; Pamphlett, Patricia; Olivetti, Lynette

    2012-07-01

    To determine the reliability of the minimum sit-to-stand height test, its responsiveness and its relationship to leg muscle strength among rehabilitation unit inpatients and outpatients. Reliability study using two measurers and two test occasions. Secondary analysis of data from two clinical trials. Inpatient and outpatient rehabilitation services in three public hospitals. Eighteen hospital patients and five others participated in the reliability study. Seventy-two rehabilitation unit inpatients and 80 outpatients participated in the clinical trials. The minimum sit-to-stand height test was assessed using a standard procedure. For the reliability study, a second tester repeated the minimum sit-to-stand height test on the same day. In the inpatient clinical trial the measures were repeated two weeks later. In the outpatient trial the measures were repeated five weeks later. Knee extensor muscle strength was assessed in the clinical trials using a hand-held dynamometer. The reliability for the minimum sit-to-stand height test was excellent (intraclass correlation coefficient (ICC) 0.91, 95% confidence interval (CI) 0.81-0.96). The standard error of measurement was 34 mm. Responsiveness was moderate in the inpatient trial (effect size: 0.53) but small in the outpatient trial (effect size: 0.16). A small proportion (8-17%) of variability in minimum sit-to-stand height test was explained by knee extensor muscle strength. The minimum sit-to-stand height test has excellent reliability and moderate responsiveness in an inpatient rehabilitation setting. Responsiveness in an outpatient rehabilitation setting requires further investigation. Performance is influenced by factors other than knee extensor muscle strength.

  10. Trajectory of self-reported pain and function and knee extensor muscle strength in young patients undergoing arthroscopic surgery for meniscal tears: A systematic review and meta-analysis.

    Science.gov (United States)

    Thorlund, Jonas Bloch; Østengaard, Lasse; Cardy, Nathan; Wilson, Fiona; Jørgensen, Claus; Juhl, Carsten Bogh

    2017-08-01

    To investigate the trajectory of patient reported pain and function and knee extensor muscle strength over time in young individuals undergoing arthroscopic meniscal surgery. Systematic review and meta-analysis METHODS: Six databases were searched up to October 13th, 2016. People aged 30 years or younger undergoing surgery for a meniscal tear. and comparator: (1) Self-reported pain and function in patients undergoing meniscal surgery compared to a non-operative control group (2). Knee extensor strength in the leg undergoing surgery compared to a healthy control group or the contra-lateral leg. Methodological quality was assessed using the SIGN 50 guidelines. No studies were found on patient reported pain and function. Six studies, including 137 patients were included in the analysis on knee extensor muscle strength. Knee extensor muscle strength was impaired in the injured leg prior to surgery and was still reduced compared with control data up to 12 months after surgery (SMD: -1.16) (95% CI: -1.83; -0.49). All included studies were assessed to have a high risk of bias. No studies were found comparing the trajectory of self-reported pain and function in patients undergoing arthroscopic surgery compared with non-operative treatments for young patients with meniscal tears. Knee extensor strength seemed to be impaired up to 12 months after surgery in young patients undergoing surgery for meniscal tears. The results of the present study should be interpreted with caution due to a limited number of available studies with high risk of bias including relatively few patients. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  11. Muscle fatigue and exhaustion during dynamic leg exercise in normoxia and hypobaric hypoxia

    DEFF Research Database (Denmark)

    Fulco, C S; Lewis, S F; Frykman, Peter

    1996-01-01

    and during exercise. MVC force was 578 +/- 29 N in normoxia and 569 +/- 29 N in hypobaria before exercise and fell, at exhaustion, to similar levels (265 +/- 10 and 284 +/- 20 N for normoxia and hypobaria, respectively; P > 0.05) that were higher (P ...Using an exercise device that integrates maximal voluntary static contraction (MVC) of knee extensor muscles with dynamic knee extension, we compared progressive muscle fatigue, i.e., rate of decline in force-generating capacity, in normoxia (758 Torr) and hypobaric hypoxia (464 Torr). Eight...... healthy men performed exhaustive constant work rate knee extension (21 +/- 3 W, 79 +/- 2 and 87 +/- 2% of 1-leg knee extension O2 peak uptake for normoxia and hypobaria, respectively) from knee angles of 90-150 degrees at a rate of 1 Hz. MVC (90 degrees knee angle) was performed before dynamic exercise...

  12. The Artificial Gravity Bed Rest Pilot Project: Effects on Knee Extensor and Plantar Flexor Muscle Groups

    Science.gov (United States)

    Caiozzo, V. J.; Haddad, F.; Lee, S.; Baker, M.; Baldwin, K. M.

    2007-01-01

    The goal of this project was to examine the effects of artificial gravity (2.5 g) on skeletal muscle strength and key anabolic/catabolic markers known to regulate muscle mass. Two groups of subjects were selected for study: 1) a 21 day-bed rest (BR) control (C) group (N=7); and 2) an AG group (N=8), which was exposed to 21 days of bed-rest plus daily 1 hr exposures to AG (2.5 g). This particular experiment was part of an integrated AG Pilot Project sponsored by NASA/Johnson Space Center. The in vivo torque-velocity relationships of the knee extensors and plantar flexors of the ankle were determined pre and post treatment. Also, pre- and post treatment biopsy samples were obtained from both the vastus lateralis and soleus muscles and were used, in part, for a series of analyses on gene expression (mRNA abundance) of key factors implicated in the anabolic versus catabolic state of the muscle. Post/Pre toque-velocity determinations revealed greater decrements in knee extensor performance in the C versus AG group (P less than 0.04). The plantar flexor muscle group of the AG subjects actually demonstrated a net gain in torque-velocity relationship; whereas, in the C group the overall post/pre responses declined (AG vs C; P less than 0.001). Measurements of muscle fiber cross-sectional area (for both muscles) demonstrated a loss of approx. 20% in the C group while no losses were evident in the AG group. RT-PCR analyses of muscle biopsy specimens demonstrated that markers of growth and cytoskeletal integrity (IGF-1, IGF-1 BP4, mechano growth factor, total RNA, and pro-collagen 3a) were higher in the AG group, whereas catabolic markers (myostatin and atrogen) were elevated in the C group. Importantly, these patterns were seen in both muscles. Based on these observations we conclude that paradigms of AG have the potential to maintain the functional, biochemical, and structural homeostasis of skeletal muscle in the face of chronic unloading states. These findings also

  13. 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.

  14. Reliability of contractile properties of the knee extensor muscles in individuals with post-polio syndrome.

    Directory of Open Access Journals (Sweden)

    Eric L Voorn

    Full Text Available To assess the reliability of contractile properties of the knee extensor muscles in 23 individuals with post-polio syndrome (PPS and 18 age-matched healthy individuals.Contractile properties of the knee extensors were assessed from repeated electrically evoked contractions on 2 separate days, with the use of a fixed dynamometer. Reliability was determined for fatigue resistance, rate of torque development (MRTD, and early and late relaxation time (RT50 and RT25, using the intraclass correlation coefficient (ICC and standard error of measurement (SEM, expressed as % of the mean.In both groups, reliability for fatigue resistance was good, with high ICCs (>0.90 and small SEM values (PPS: 7.1%, healthy individuals: 7.0%. Reliability for contractile speed indices varied, with the best values found for RT50 (ICCs>0.82, SEM values <2.8%. We found no systematic differences between test and retest occasions, except for RT50 in healthy subjects (p = 0.016.In PPS and healthy individuals, the reliability of fatigue resistance, as obtained from electrically evoked contractions is high. The reliability of contractile speed is only moderate, except for RT50 in PPS, demonstrating high reliability.This was the first study to examine the reliability of electrically evoked contractile properties in individuals with PPS. Our results demonstrate its potential to study mechanisms underlying muscle fatigue in PPS and to evaluate changes in contractile properties over time in response to interventions or from natural course.

  15. Recombinant Uncarboxylated Osteocalcin Per Se Enhances Mouse Skeletal Muscle Glucose Uptake in both Extensor Digitorum Longus and Soleus Muscles

    Directory of Open Access Journals (Sweden)

    Xuzhu Lin

    2017-11-01

    Full Text Available Emerging evidence suggests that undercarboxylated osteocalcin (ucOC improves muscle glucose uptake in rodents. However, whether ucOC can directly increase glucose uptake in both glycolytic and oxidative muscles and the possible mechanisms of action still need further exploration. We tested the hypothesis that ucOC per se stimulates muscle glucose uptake via extracellular signal-regulated kinase (ERK, adenosine monophosphate-activated protein kinase (AMPK, and/or the mechanistic target of rapamycin complex 2 (mTORC2-protein kinase B (AKT-AKT substrate of 160 kDa (AS160 signaling cascade. Extensor digitorum longus (EDL and soleus muscles from male C57BL/6 mice were isolated, divided into halves, and then incubated with ucOC with or without the pretreatment of ERK inhibitor U0126. ucOC increased muscle glucose uptake in both EDL and soleus. It also enhanced phosphorylation of ERK2 (Thr202/Tyr204 and AS160 (Thr642 in both muscle types and increased mTOR phosphorylation (Ser2481 in EDL only. ucOC had no significant effect on the phosphorylation of AMPKα (Thr172. The inhibition of ucOC-induced ERK phosphorylation had limited effect on ucOC-stimulated glucose uptake and AS160 phosphorylation in both muscle types, but appeared to inhibit the elevation in AKT phosphorylation only in EDL. Taken together, ucOC at the physiological range directly increased glucose uptake in both EDL and soleus muscles in mouse. The molecular mechanisms behind this ucOC effect on muscle glucose uptake seem to be muscle type-specific, involving enhanced phosphorylation of AS160 but limitedly modulated by ERK phosphorylation. Our study suggests that, since ucOC increases muscle glucose uptake without insulin, it could be considered as a potential agent to improve muscle glucose uptake in insulin resistant conditions.

  16. Functional and morphological adaptations to aging in knee extensor muscles of physically active men.

    Science.gov (United States)

    Baroni, Bruno Manfredini; Geremia, Jeam Marcel; Rodrigues, Rodrigo; Borges, Marcelo Krás; Jinha, Azim; Herzog, Walter; Vaz, Marco Aurélio

    2013-10-01

    It is not known if a physically active lifestyle, without systematic training, is sufficient to combat age-related muscle and strength loss. Therefore, the purpose of this study was to evaluate if the maintenance of a physically active lifestyle prevents muscle impairments due to aging. To address this issue, we evaluated 33 healthy men with similar physical activity levels (IPAQ = 2) across a large range of ages. Functional (torque-angle and torque-velocity relations) and morphological (vastus lateralis muscle architecture) properties of the knee extensor muscles were assessed and compared between three age groups: young adults (30 ± 6 y), middle-aged subjects (50 ± 7 y) and elderly subjects (69 ± 5 y). Isometric peak torques were significantly lower (30% to 36%) in elderly group subjects compared with the young adults. Concentric peak torques were significantly lower in the middle aged (18% to 32%) and elderly group (40% to 53%) compared with the young adults. Vastus lateralis thickness and fascicles lengths were significantly smaller in the elderly group subjects (15.8 ± 3.9 mm; 99.1 ± 25.8 mm) compared with the young adults (19.8 ± 3.6 mm; 152.1 ± 42.0 mm). These findings suggest that a physically active lifestyle, without systematic training, is not sufficient to avoid loss of strength and muscle mass with aging.

  17. Muscle response to leg lengthening during distraction osteogenesis.

    Science.gov (United States)

    Thorey, Fritz; Bruenger, Jens; Windhagen, Henning; Witte, Frank

    2009-04-01

    Continuous lengthening of intact muscles during distraction osteogenesis leads to an increase of sarcomeres and enhances the regeneration of tendons and blood vessels. A high distraction rate leads to an excessive leg and muscle lengthening and might cause damages of muscle fibers with fibrosis, necrosis, and muscle weakness. Complications like muscle contractures or atrophy after postoperative immobilization emphazize the importance of muscles and their function in the clinical outcome. In an animal model of distraction osteogenesis, 18 sheep were operated with an external fixator followed by 4 days latency, 21 days distraction (1.25 mm per day) and 51 days consolidation. The anatomical location (gastrocnemius, peroneus tertius, and first flexor digitorum longus muscle), dimension and occurrence of muscular defects were characterized histologically. The callus formation and leg axis was monitored by weekly X-rays. Additionally, serum creatine kinase was analyzed during a distraction and consolidation period. Significant signs of muscle lesions in all three observed muscles can be found postoperatively, whereas normal callus formation and regular leg axis was observed radiologically. The peroneus tertius and first flexor digitorum longus muscles were found to have significantly more signs of fibrosis, inflammatory, and necrosis. Creatine kinase showed two peaks: 4 and 39 days postoperative as an indication of muscle damage and regeneration. The study implicates that muscle damages should be considered when a long-distance distraction osteogenesis is planned. The surgeon should consider these muscle responses and individually discuss a two-stage treatment or additional muscle tendon releases to minimize the risk of muscle damages.

  18. Muscle power is an important measure to detect deficits in muscle function in hip osteoarthritis

    DEFF Research Database (Denmark)

    Bieler, Theresa; Magnusson, Stig Peter; Christensen, Helle Elisabeth

    2017-01-01

    that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with hip osteoarthritis. Implications for Rehabilitation Even in patients with mild symptoms not awaiting hip replacement a generalized muscle weakening......: The symptomatic extremity in patients was significantly (p asymmetry in knee extensor strength (6%, p ... in patients, but had no asymmetry in leg extensor power. CONCLUSIONS: Patients had generalized weakening of the affected lower extremity and numerically the largest asymmetry was evident for leg extensor power. In contrast, healthy peers had no asymmetry in leg extensor power. These results indicate...

  19. Sex differences in muscle morphology of the knee flexors and knee extensors.

    Directory of Open Access Journals (Sweden)

    Fearghal P Behan

    Full Text Available Females experience higher risk of anterior cruciate ligament (ACL injuries; males experience higher risk of hamstring strain injuries. Differences in injury may be partially due to sex differences in knee flexor (KF to knee extensor (KE muscle size ratio and the proportional size of constituent muscles.To compare the absolute and proportional size, and mass distribution, of individual KE and KF muscles, as well as overall size and balance (size ratio of these muscle groups between the sexes.T1-weighted axial plane MR images (1.5T of healthy untrained young males and females (32 vs 34 were acquired to determine thigh muscle anatomical cross-sectional area (ACSA. Maximal ACSA (ACSAmax of constituent muscles, summated for KF and KE muscle groups, and the KF:KE ratio were calculated.Females had 25.3% smaller KE ACSAmax (70.9±12.1 vs 93.6±10.3 cm2; P<0.001 and 29.6% smaller KF ACSAmax than males (38.8±7.3cm2 vs 55.1±7.3cm2; P<0.001. Consequently, females had lower KF:KE ACSA ratio (P = 0.031. There were sex differences in the proportional size of 2/4 KE and 5/6 KF. In females, vastus lateralis (VL, biceps femoris long-head (BFlh and semimembranosus (SM were a greater proportion and sartorius (SA, gracilis (GR and biceps femoris short-head (BFsh a smaller proportion of their respective muscle groups compared to males (All P<0.05.Sex differences in KF:KE ACSAmax ratio may contribute to increased risk of ACL injury in females. Sex discrepancies in absolute and proportional size of SA, GR, VL and BFlh may contribute further anatomical explanations for sex differences in injury incidence.

  20. Surgical Treatment of Traumatic Myositis Ossificans of the Extensor Carpi Radialis Muscle in a Dog.

    Science.gov (United States)

    Morton, Bridget A; Hettlich, Bianca F; Pool, Roy R

    2015-07-01

    To report clinical signs, diagnostic imaging findings, and outcome in a dog with traumatic myositis ossificans of the origin of the extensor carpi radialis muscle. Clinical report. An 8-month-old intact female Irish Setter Dog. After radiographic and computed tomographic evaluation of an osseous proliferation arising from the cranial cortex of the right distal humeral diaphysis, the protruding bone was surgically removed and evaluated by histopathology. Traumatic myositis ossificans was successfully treated with surgical removal of the osseous proliferation resulting in improved postoperative range of motion of the right elbow joint. There was no evidence of lameness or abnormal bone regrowth associated with the surgical site radiographically at follow up. Surgical removal of a traumatic myositis ossificans lesion resulted in full return to function in a young, competitive show dog. © Copyright 2014 by The American College of Veterinary Surgeons.

  1. β-alanine supplementation improves isometric endurance of the knee extensor muscles

    Directory of Open Access Journals (Sweden)

    Sale Craig

    2012-06-01

    Full Text Available Abstract Background We examined the effect of four weeks of β-alanine supplementation on isometric endurance of the knee extensors at 45% maximal voluntary isometric contraction (MVIC. Methods Thirteen males (age 23 ± 6 y; height 1.80 ± 0.05 m; body mass 81.0 ± 10.5 kg, matched for pre-supplementation isometric endurance, were allocated to either a placebo (n = 6 or β-alanine (n = 7; 6.4 g·d-1 over 4 weeks supplementation group. Participants completed an isometric knee extension test (IKET to fatigue, at an intensity of 45% MVIC, before and after supplementation. In addition, two habituation tests were completed in the week prior to the pre-supplementation test and a further practice test was completed in the week prior to the post-supplementation test. MVIC force, IKET hold-time, and impulse generated were recorded. Results IKET hold-time increased by 9.7 ± 9.4 s (13.2% and impulse by 3.7 ± 1.3 kN·s-1 (13.9% following β-alanine supplementation. These changes were significantly greater than those in the placebo group (IKET: t(11 = 2.9, p ≤0.05; impulse: t(11 = 3.1, p ≤ 0.05. There were no significant changes in MVIC force in either group. Conclusion Four weeks of β-alanine supplementation at 6.4 g·d-1 improved endurance capacity of the knee extensors at 45% MVIC, which most likely results from improved pH regulation within the muscle cell as a result of elevated muscle carnosine levels.

  2. Magnetic Resonance Assessment of Hypertrophic and Pseudo-Hypertrophic Changes in Lower Leg Muscles of Boys with Duchenne Muscular Dystrophy and Their Relationship to Functional Measurements.

    Directory of Open Access Journals (Sweden)

    Ravneet S Vohra

    Full Text Available The primary objectives of this study were to evaluate contractile and non-contractile content of lower leg muscles of boys with Duchenne muscular dystrophy (DMD and determine the relationships between non-contractile content and functional abilities.Lower leg muscles of thirty-two boys with DMD and sixteen age matched unaffected controls were imaged. Non-contractile content, contractile cross sectional area and non-contractile cross sectional area of lower leg muscles (tibialis anterior, extensor digitorum longus, peroneal, medial gastrocnemius and soleus were assessed by magnetic resonance imaging (MRI. Muscle strength, timed functional tests and the Brooke lower extremity score were also assessed.Non-contractile content of lower leg muscles (peroneal, medial gastrocnemius, and soleus was significantly greater than control group (p<0.05. Non-contractile content of lower leg muscles correlated with Brooke score (rs = 0.64-0.84 and 30 feet walk (rs = 0.66-0.80. Dorsiflexor (DF and plantarflexor (PF specific torque was significantly different between the groups.Overall, non-contractile content of the lower leg muscles was greater in DMD than controls. Furthermore, there was an age dependent increase in contractile content in the medial gastrocnemius of boys with DMD. The findings of this study suggest that T1 weighted MR images can be used to monitor disease progression and provide a quantitative estimate of contractile and non-contractile content of tissue in children with DMD.

  3. Comparison of the electrical activity in upper trapezius and wrist extensor muscles during two typewriting conditions

    Directory of Open Access Journals (Sweden)

    João Carlos Comel

    Full Text Available Introduction The proper use of the position of the arm and wrist while typing may reduce muscle overload and prevent musculoskeletal disorders.Objective To evaluate the electromyographic activity of upper trapezius and wrist extensor muscles during two typewriting conditions.Materials and methods : Six healthy females (Xage = 42 years,SD= 10, (Xheight = 1.65m, SD = 0.05 and (Xweight = 71kg, SD = 16 participated in this study. The task was performed with a newly developed arm support and without the support. A perceived exertion scale was used with all subjects. An ANOVA with repeated measures was used to verify differences in perceived exertion and root mean square (RMS.Results There were no statistically significant differences for the RMS between the typewriting tasks. The condition without arm support presented a significantly greater mean velocity and amount of words typed (P= 0.02; P= 0.03 and there was a significant difference in perceived exertion during the condition without arm support (P= 0.03. Electromyographic activity did not present differences.Conclusion The muscle electrical activity was not altered regardless the arm support and occurred the improvement of the perceived exertion after 10 minutes of typing without support. Long-term studies are needed.

  4. Muscle activity of leg muscles during unipedal stance on therapy devices with different stability properties.

    Science.gov (United States)

    Wolburg, Thomas; Rapp, Walter; Rieger, Jochen; Horstmann, Thomas

    2016-01-01

    To test the hypotheses that less stable therapy devices require greater muscle activity and that lower leg muscles will have greater increases in muscle activity with less stable therapy devices than upper leg muscles. Cross-sectional laboratory study. Laboratory setting. Twenty-five healthy subjects. Electromyographic activity of four lower (gastrocnemius medialis, soleus, tibialis anterior, peroneus longus) and four upper leg muscles (vastus medialis and lateralis, biceps femoris, semitendinosus) during unipedal quiet barefoot stance on the dominant leg on a flat rigid surface and on five therapy devices with varying stability properties. Muscle activity during unipedal stance differed significantly between therapy devices (P < 0.001). The order from lowest to highest relative muscle activity matched the order from most to least stable therapy device. There was no significant interaction between muscle location (lower versus upper leg) and therapy device (P = 0.985). Magnitudes of additional relative muscle activity for the respective therapy devices differed substantially among lower extremity muscles. The therapy devices offer a progressive increase in training intensity, and thus may be useful for incremental training programs in physiotherapeutic practice and sports training programs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Humeral external rotation handling by using the Bobath concept approach affects trunk extensor muscles electromyography in children with cerebral palsy.

    Science.gov (United States)

    Grazziotin Dos Santos, C; Pagnussat, Aline S; Simon, A S; Py, Rodrigo; Pinho, Alexandre Severo do; Wagner, Mário B

    2014-10-20

    This study aimed to investigate the electromyographic activity of cervical and trunk extensors muscles in children with cerebral palsy during two handlings according to the Bobath concept. A crossover trial involving 40 spastic diplegic children was conducted. Electromyography (EMG) was used to measure muscular activity at sitting position (SP), during shoulder internal rotation (IR) and shoulder external rotation (ER) handlings, which were performed using the elbow joint as key point of control. Muscle recordings were performed at the fourth cervical (C4) and at the tenth thoracic (T10) vertebral levels. The Gross Motor Function Classification System (GMFCS) was used to assess whether muscle activity would vary according to different levels of severity. Humeral ER handling induced an increase on EMG signal of trunk extensor muscles at the C4 (P=0.007) and T10 (P<0.001) vertebral levels. No significant effects were observed between SP and humeral IR handling at C4 level; However at T10 region, humeral IR handling induced an increase of EMG signal (P=0.019). Humeral ER resulted in an increase of EMG signal at both levels, suggesting increase of extensor muscle activation. Furthermore, the humeral ER handling caused different responses on EMG signal at T10 vertebra level, according to the GMFCS classification (P=0.017). In summary, an increase of EMG signal was observed during ER handling in both evaluated levels, suggesting an increase of muscle activation. These results indicate that humeral ER handling can be used for diplegic CP children rehabilitation to facilitate cervical and trunk extensor muscles activity in a GMFCS level-dependent manner. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Comparison Between Elite and Subelite Swimmers on Dry Land and Tumble Turn Leg Extensor Force-Time Characteristics.

    Science.gov (United States)

    Jones, Julian V; Pyne, David B; Haff, G Greg; Newton, Robert U

    2018-06-01

    Jones, JV, Pyne, DB, Haff, GG, and Newton, RU. Comparison between elite and subelite swimmers on dry land and tumble turn leg extensor force-time characteristics. J Strength Cond Res 32(6): 1762-1769, 2018-Elite swimmers demonstrate faster swimming turn times that are potentially a result of having better strength-power characteristics than subelite swimmers. We quantified differences between dry-land and swimming turn force-time characteristics in elite swimmers and subelite swimmers. Subelite (11 males: 17.4 ± 0.6 years; 10 females: 17.1 ± 0.6 years) and elite swimmers (15 male: 23.2 ± 2.3 years; 7 female: 21.6 ± 2.5 years) were tested in a cross-sectional design. All swimmers performed a body weight and loaded (20 kg females, 30 kg males) squat jump (SJ) on a portable force platform. On the same day, all swimmers completed swimming turn analyses using a force platform fixed within the pool wall. The magnitude of difference between groups was estimated using a standardized mean difference (effect size statistic). Elite male and female swimmers had superior swimming turn and dry-land force-time characteristics to subelite swimmers in all tests. The standardized mean differences between groups ranged from small to very large. The largest differences were SJ peak velocity unloaded (3.07 ± 1.0 m·s males, 3.49 ± 2.29 m·s females; standardized mean difference ± 90% confidence limits) and SJ peak power unloaded (2.59 ± 0.79 w male, 2.80 ± 1.64 w female) with elite male and female swimmers having a ∼25-50% higher performance than the subelites in both characteristics. Elite swimmers exhibit superior strength and power characteristics for the swimming turn compared with younger and less experienced swimmers. A well-planned and executed strength and conditioning program is needed for emerging swimmers to develop these qualities, as they transition to senior levels.

  7. An MRI volumetric study for leg muscles in congenital clubfoot.

    Science.gov (United States)

    Ippolito, Ernesto; Dragoni, Massimiliano; Antonicoli, Marco; Farsetti, Pasquale; Simonetti, Giovanni; Masala, Salvatore

    2012-10-01

    To investigate both volume and length of the three muscle compartments of the normal and the affected leg in unilateral congenital clubfoot. Volumetric magnetic resonance imaging (VMRI) of the anterior, lateral and postero-medial muscular compartments of both the normal and the clubfoot leg was obtained in three groups of seven patients each, whose mean age was, respectively, 4.8 months, 11.1 months and 4.7 years. At diagnosis, all the unilateral congenital clubfeet had a Pirani score ranging from 4.5 to 5.5 points, and all of them had been treated according to a strict Ponseti protocol. All the feet had percutaneous lengthening of the Achilles tendon. A mean difference in both volume and length was found between the three muscular compartments of the leg, with the muscles of the clubfoot side being thinner and shorter than those of the normal side. The distal tendon of the tibialis anterior, peroneus longus and triceps surae (Achilles tendon) were longer than normal on the clubfoot side. Our study shows that the three muscle compartments of the clubfoot leg are thinner and shorter than normal in the patients of the three groups. The difference in the musculature volume of the postero-medial compartment between the normal and the affected side increased nine-fold from age group 2 to 3, while the difference in length increased by 20 %, thus, showing that the muscles of the postero-medial compartment tend to grow in both thickness and length much less than the muscles of the other leg compartments.

  8. Electromyographic activity of the trunk extensor muscles: effect of varying hip position and lumbar posture during Roman chair exercise.

    Science.gov (United States)

    Mayer, John M; Verna, Joe L; Manini, Todd M; Mooney, Vert; Graves, James E

    2002-11-01

    To evaluate the effect of hip position and lumbar posture on the surface electromyographic activity of the trunk extensors during Roman chair exercise. Descriptive, repeated measures. University-based musculoskeletal research laboratory. Twelve healthy volunteers (7 men, 5 women; age range, 18-35y) without a history of low back pain were recruited from a university setting. Not applicable. Surface electromyographic activity was recorded from the lumbar extensor, gluteal, and hamstring musculature during dynamic Roman chair exercise. For each muscle group, electromyographic activity (mV/rep) was compared among exercises with internal hip rotation and external hip rotation and among exercises by using a typical lumbar posture (nonbiphasic) and a posture that accentuated lumbar lordosis (biphasic). For the lumbar extensors, electromyographic activity during exercise was 18% greater with internal hip rotation than external hip rotation (Phamstrings, there was no difference in electromyographic activity between internal and external hip rotation or between biphasic and nonbiphasic postures (P >.05). The level of recruitment of the lumbar extensors can be modified during Roman chair exercise by altering hip position and lumbar posture. Clinicians can use these data to develop progressive exercise protocols for the lumbar extensors with a variety of resistance levels without the need for complex equipment. Copyright 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

  9. Association between Thigh Muscle Volume and Leg Muscle Power in Older Women.

    Directory of Open Access Journals (Sweden)

    Ulrich Lindemann

    Full Text Available The construct of sarcopenia is still discussed with regard to best appropriate measures of muscle volume and muscle function. The aim of this post-hoc analysis of a cross-sectional experimental study was to investigate and describe the hierarchy of the association between thigh muscle volume and measurements of functional performance in older women. Thigh muscle volume of 68 independently living older women (mean age 77.6 years was measured via magnetic resonance imaging. Isometric strength was assessed for leg extension in a movement laboratory in sitting position with the knee flexed at 90° and for hand grip. Maximum and habitual gait speed was measured on an electronic walk way. Leg muscle power was measured during single leg push and during sit-to-stand performance. Thigh muscle volume was associated with sit-to-stand performance power (r = 0.628, leg push power (r = 0.550, isometric quadriceps strength (r = 0.442, hand grip strength (r = 0.367, fast gait speed (r = 0.291, habitual gait speed (r = 0.256, body mass index (r = 0.411 and age (r = -0.392. Muscle power showed the highest association with thigh muscle volume in healthy older women. Sit-to-stand performance power showed an even higher association with thigh muscle volume compared to single leg push power.

  10. A study on the strength of leg extention and leg curl exercise measured with the "Tremax System" and the "ADR" (Aero Dynamic Resistance System)

    OpenAIRE

    安藤, 勝英

    1995-01-01

    This is a study on the nature of the extensor and flexor muscles by the leg extention and leg curl exercise. The strength of the static muscles were measured with the "Tremax system" and for the strength of the dynamic muscles the "ADR" was used. Measuring the strength of the extensor muscles at bar no.1 to 4 of the Tremax System,it comes to a maximum at bar no.2 (extention 60°) but it declines radically when approaching extention 0°. Compared to the extensor muscles, the flexor muscules show...

  11. Magnetic Resonance Assessment of Hypertrophic and Pseudo-Hypertrophic Changes in Lower Leg Muscles of Boys with Duchenne Muscular Dystrophy and Their Relationship to Functional Measurements.

    Science.gov (United States)

    Vohra, Ravneet S; Lott, Donovan; Mathur, Sunita; Senesac, Claudia; Deol, Jasjit; Germain, Sean; Bendixen, Roxanna; Forbes, Sean C; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

    2015-01-01

    The primary objectives of this study were to evaluate contractile and non-contractile content of lower leg muscles of boys with Duchenne muscular dystrophy (DMD) and determine the relationships between non-contractile content and functional abilities. Lower leg muscles of thirty-two boys with DMD and sixteen age matched unaffected controls were imaged. Non-contractile content, contractile cross sectional area and non-contractile cross sectional area of lower leg muscles (tibialis anterior, extensor digitorum longus, peroneal, medial gastrocnemius and soleus) were assessed by magnetic resonance imaging (MRI). Muscle strength, timed functional tests and the Brooke lower extremity score were also assessed. Non-contractile content of lower leg muscles (peroneal, medial gastrocnemius, and soleus) was significantly greater than control group (pmuscles correlated with Brooke score (rs = 0.64-0.84) and 30 feet walk (rs = 0.66-0.80). Dorsiflexor (DF) and plantarflexor (PF) specific torque was significantly different between the groups. Overall, non-contractile content of the lower leg muscles was greater in DMD than controls. Furthermore, there was an age dependent increase in contractile content in the medial gastrocnemius of boys with DMD. The findings of this study suggest that T1 weighted MR images can be used to monitor disease progression and provide a quantitative estimate of contractile and non-contractile content of tissue in children with DMD.

  12. The Comparing the Leg Muscles Electromyography during Single Leg Drop Landing in Pesplanus and Normal Men

    Directory of Open Access Journals (Sweden)

    mostafa bazvand

    2016-03-01

    Full Text Available Objective: pesplanus is one of the changes that brings about changes in muscle activation patterns. Being aware of muscles activity changes in various standing positions among pesplanus patients provides insights into preventing lower extremity injuries in this population. The aim of this study was to compare leg muscles electromyography during various standing positions in pesplanus and normal subjects. Methods: 60 healthy male university students, 30 subjects with pesplanus deformity (with average age 23/54±3/57 year, average height 175/34±7/62 cm, average weight 74/87±10/72 kg and 30 normal subjects (with average age 22/97±2/38 year, average height 176/6±5/59 cm, average weight 73/58±8/36 kg participated in this comparative study. Deformity of pesplanus was assessed with navicular drop test. Each subject performed single-leg landing dropping from 30cm height onto a force platform where muscles activity was recorded with EMG device. For data analysis, Matlab and Spss softwares were used and independent sample t-test was used to compare the dependent variables at a significance level of P &le 0/05. Results: Significant differences were observed between the two groups for the activities of the longus peroneus and anterior tibialis muscles ( p&le0/05 while no significant differences were observed in other muscles. Conclusion: The changes in the normal structure of the foot might affect muscle activities during standing, which can cause changes in the injury patterns. Therefore, it is proposed that focusing on corrective exercises and therapy plan can reduce these risks.

  13. Effects of combined and classic training on different isometric rate of force development parameters of leg extensors in female volleyball players: Discriminative analysis approach

    Directory of Open Access Journals (Sweden)

    Rajić Branislav

    2013-01-01

    Full Text Available Background: The aim of this study is to verify the effects of the combined and classic training of different isometric rates of force development (RFD parameters of legs. Materials and Methods: Three groups of female athletes was tested: Experimental group (N = 12, classically trained group (N = 11, and control group (N = 20 of athletes. The isometric "standing leg extension" and "Rise on Toes" tests were conducted to evaluate the maximal force, time necessary time to reach it and the RFD analyzed at 100 ms, 180 ms, 250 ms from the onset, and 50-100% of its maximal result. Results: The maximal RFD of legs and calves are dominant explosive parameters. Special training enhanced the RFD of calves of GROUP SPEC at 100 ms (P = 0.05, at 180 ms (P = 0.039, at 250 ms (P = 0.039, at 50% of the F max (P = 0.031 and the F max (P = 0.05. Domination of GROUP SPEC toward GROUP CLASS and GROUP CONTROL is in case of legs at 100 ms (P = 0.04; at 180 ms (P = 0.04; at 250 ms (P = 0.00; at 50% of the F max (P = 0.01 and at the F max (P = 0.00; in case of calves at 100 ms (P = 0.07; 180 ms (P = 0.001; at 250 ms (P = 0.00; at 50% of the F max (P = 0.00 and at F max (P = 0.000. Conclusion: Dominant explosive factors are maximal RFD of leg extensors and calves, and legs at 250ms. Specific training enhanced explosiveness of calves of GROUP SPEC general and partial domination of GROUP SPEC by 87% over GROUP CLASS , and 35% over GROUP CONTROL .

  14. THE EFFECTS OF SINGLE LEG HOP PROGRESSION AND DOUBLE LEGS HOP PROGRESSION EXERCISE TO INCREASE SPEED AND EXPLOSIVE POWER OF LEG MUSCLE

    Directory of Open Access Journals (Sweden)

    Nining W. Kusnanik

    2015-05-01

    Full Text Available The main purpose of this study was to determine the effect of single leg hop progression and double legs hop progression exercise to increase speed and explosive power of leg muscles. Plyometric is one of the training methods that can increase explosive power. There are many models of plyometric training including single leg hop progression and double leg hop progression. This research was experimental using match subject design techniques. The subjects of this study were 39 students who joined basketball school club. There were 3 groups in this study: Group 1 were 13 students who given sin¬gle leg hop progression exercise, Group 2 were 13 students who given double legs hop progression exercise, Group 3 were 13 students who given conventional exercise. The data was collected during pre test and post test by testing 30m speed running and vertical jump. The data was analyzed using Analysis of Varians (Anova. It was found that there were significantly increased on speed and explosive power of leg muscles of Group 1 and Group 2. It can be stated that single leg hop progression exercise was more effective than double leg hop progression exercise. The recent findings supported the hypothesis that single leg hop progression and double legs hop progression exercise can increase speed and explosive power of leg muscles. These finding were supported by some previous studies (Singh, et al, 2011; Shallaby, H.K., 2010. The single leg hop progression is more effective than double legs hop progression. This finding was consistent with some previous evidences (McCurdy, et al, 2005; Makaruk et al, 2011.

  15. 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.

  16. Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes

    Directory of Open Access Journals (Sweden)

    Josh L. Secomb, Sophia Nimphius, Oliver R.L. Farley, Lina E. Lundgren, Tai T. Tran, Jeremy M. Sheppard

    2015-12-01

    Full Text Available The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ and squat jump (SJ, and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23 and female (n = 7 surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isometric mid-thigh pull (IMTP. In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73 were identified between the thickness of the vastus lateralis (VL and lateral gastrocnemius (LG muscles, and VL pennation angle and; peak force (PF in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59 were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59 also present with IMTP PF. These results suggest that greater thickness of the VL and LG were related to improved maximal dynamic and isometric strength, likely due to increased hypertrophy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle.

  17. Effects of chronic administration of clenbuterol on contractile properties and calcium homeostasis in rat extensor digitorum longus muscle.

    Science.gov (United States)

    Sirvent, Pascal; Douillard, Aymerick; Galbes, Olivier; Ramonatxo, Christelle; Py, Guillaume; Candau, Robin; Lacampagne, Alain

    2014-01-01

    Clenbuterol, a β2-agonist, induces skeletal muscle hypertrophy and a shift from slow-oxidative to fast-glycolytic muscle fiber type profile. However, the cellular mechanisms of the effects of chronic clenbuterol administration on skeletal muscle are not completely understood. As the intracellular Ca2+ concentration must be finely regulated in many cellular processes, the aim of this study was to investigate the effects of chronic clenbuterol treatment on force, fatigue, intracellular calcium (Ca2+) homeostasis and Ca2+-dependent proteolysis in fast-twitch skeletal muscles (the extensor digitorum longus, EDL, muscle), as they are more sensitive to clenbuterol-induced hypertrophy. Male Wistar rats were chronically treated with 4 mg.kg-1 clenbuterol or saline vehicle (controls) for 21 days. Confocal microscopy was used to evaluate sarcoplasmic reticulum Ca2+ load, Ca2+-transient amplitude and Ca2+ spark properties. EDL muscles from clenbuterol-treated animals displayed hypertrophy, a shift from slow to fast fiber type profile and increased absolute force, while the relative force remained unchanged and resistance to fatigue decreased compared to control muscles from rats treated with saline vehicle. Compared to control animals, clenbuterol treatment decreased Ca2+-transient amplitude, Ca2+ spark amplitude and frequency and the sarcoplasmic reticulum Ca2+ load was markedly reduced. Conversely, calpain activity was increased by clenbuterol chronic treatment. These results indicate that chronic treatment with clenbuterol impairs Ca2+ homeostasis and this could contribute to the remodeling and functional impairment of fast-twitch skeletal muscle.

  18. Heterogeneous recruitment of quadriceps muscle portions and fibre types during moderate intensity knee-extensor exercise: effect of thigh occlusion

    DEFF Research Database (Denmark)

    Krustrup, Peter; Söderlund, Karin; Relu, Mihai U.

    2009-01-01

    temperature increase (DeltaT(m)) in RF was 0.52+/-0.09 degrees C, which was 57% and 73% higher (Pmuscle CP in slow twitch (ST) and fast......The involvement of quadriceps femoris muscle portions and fibre type recruitment was studied during submaximal knee-extensor exercise without and with thigh occlusion (OCC) and compared with responses during intense exercise. Six healthy male subjects performed 90-s of moderate exercise without...... twitch (FT) fibres was 81% and 91% of resting levels, respectively, with lower (Pfibres had CP levels below mean-1 SD, respectively, with corresponding values for FT fibres being 41...

  19. Muscle Activity in Single- vs. Double-Leg Squats.

    Science.gov (United States)

    DeFOREST, Bradley A; Cantrell, Gregory S; Schilling, Brian K

    Muscular activity, vertical displacement and ground reaction forces of back squats (BS), rear-leg elevated split squats (RLESS) and split squats (SS) were examined. Nine resistance-trained men reported for two sessions. The first session consisted of the consent process, practice, and BS 1-repetition maximum testing. In the second session, participants performed the three exercises while EMG, displacment and ground reaction force data (one leg on plate) were collected. EMG data were collected from the gluteus maximus (GMX), biceps femoris (BF), semitendinosus (ST), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), tibialis anterior (TA), and medial gastrocnemius (MGas) of the left leg (non-dominant, front leg for unilateral squats). Load for BS was 85% one repetition maximum, and RLESS and SS were performed at 50% of BS load. Repeated measures ANOVA was used to compare all variables for the three exercises, with Bonferroni adjustments for post hoc multiple comparisons, in addition to calculation of standardized mean differences (ES). Muscle activity was similar between exercises except for biceps femoris, which was significantly higher during RLESS than SS during both concentric and eccentric phases (ES = 2.11; p=0.012 and ES= 2.19; p=0.008), and significantly higher during BS than the SS during the concentric phase (ES = 1.78; p=0.029). Vertical displacement was similar between all exercises. Peak vertical force was similar between BS and RLESS and significantly greater during RLESS than SS (ES = 3.03; p=0.001). These findings may be helpful in designing resistance training programs by using RLESS if greater biceps femoris activity is desired.

  20. Trajectory of self-reported pain and function and knee extensor muscle strength in young patients undergoing arthroscopic surgery for meniscal tears

    DEFF Research Database (Denmark)

    Thorlund, Jonas Bloch; Østengaard, Lasse; Cardy, Nathan

    2017-01-01

    . PATIENTS AND INTERVENTION: People aged 30 years or younger undergoing surgery for a meniscal tear. OUTCOMES: and comparator: (1) Self-reported pain and function in patients undergoing meniscal surgery compared to a non-operative control group (2). Knee extensor strength in the leg undergoing surgery...... the trajectory of self-reported pain and function in patients undergoing arthroscopic surgery compared with non-operative treatments for young patients with meniscal tears. Knee extensor strength seemed to be impaired up to 12 months after surgery in young patients undergoing surgery for meniscal tears...

  1. Baseline Mechanical and Neuromuscular Profile of Knee Extensor and Flexor Muscles in Professional Soccer Players at the Start of the Pre-Season.

    Science.gov (United States)

    García-García, Oscar; Serrano-Gómez, Virginia; Hernández-Mendo, Antonio; Morales-Sánchez, Verónica

    2017-09-01

    The aim of the study was to determine the mechanical and neuromuscular profile of knee extensor and flexor muscles in professional soccer players at the start of the pre-season, and to calculate percentages for symmetry, as well as examine differences according to the player's positional role. The vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF) and biceps femoris (BF) of 16 professional soccer players were evaluated by means of tensiomyography (TMG) on the first day of the pre-season. A paired-samples t test (p < .05) was used to compare the dominant and non-dominant lower limb. One-way ANOVA was applied, with the positional role as an independent factor. No differences were observed between the dominant and non-dominant leg. The highest degree of symmetry corresponded to the VM (92.5 ± 2.7%), and the lowest to the BF (80.7 ± 10.9%). The positional role was associated with significant differences in some of the variables for the BF, RF and VM, although only the half-relaxation time in the BF and the time to sustain force in the VM differed across all the playing positions considered. TMG was shown to be a useful way of evaluating the neuromuscular characteristics of soccer players at the start of the pre-season, and of establishing baseline values for individual players.

  2. Baseline Mechanical and Neuromuscular Profile of Knee Extensor and Flexor Muscles in Professional Soccer Players at the Start of the Pre-Season

    Directory of Open Access Journals (Sweden)

    García-García Oscar

    2017-08-01

    Full Text Available The aim of the study was to determine the mechanical and neuromuscular profile of knee extensor and flexor muscles in professional soccer players at the start of the pre-season, and to calculate percentages for symmetry, as well as examine differences according to the player’s positional role. The vastus medialis (VM, vastus lateralis (VL, rectus femoris (RF and biceps femoris (BF of 16 professional soccer players were evaluated by means of tensiomyography (TMG on the first day of the pre-season. A paired-samples t test (p < .05 was used to compare the dominant and non-dominant lower limb. One-way ANOVA was applied, with the positional role as an independent factor. No differences were observed between the dominant and non-dominant leg. The highest degree of symmetry corresponded to the VM (92.5 ± 2.7%, and the lowest to the BF (80.7 ± 10.9%. The positional role was associated with significant differences in some of the variables for the BF, RF and VM, although only the half-relaxation time in the BF and the time to sustain force in the VM differed across all the playing positions considered. TMG was shown to be a useful way of evaluating the neuromuscular characteristics of soccer players at the start of the pre-season, and of establishing baseline values for individual players.

  3. Activation amplitude and temporal synchrony among back extensor and abdominal muscles during a controlled transfer task: comparison of men and women.

    Science.gov (United States)

    Hubley-Kozey, Cheryl L; Butler, Heather L; Kozey, John W

    2012-08-01

    Muscle synergies are important for spinal stability, but few studies examine temporal responses of spinal muscles to dynamic perturbations. This study examined activation amplitudes and temporal synergies among compartments of the back extensor and among abdominal wall muscles in response to dynamic bidirectional moments of force. We further examined whether responses were different between men and women. 19 women and 18 men performed a controlled transfer task. Surface electromyograms from bilateral sites over 6 back extensor compartments and 6 abdominal wall muscle sites were analyzed using principal component analysis. Key features were extracted from the measured electromyographic waveforms capturing amplitude and temporal variations among muscle sites. Three features explained 97% of the variance. Scores for each feature were computed for each measured waveform and analysis of variance found significant (pWomen had more differences among muscle sites than men for the lateral flexion moment feature. For the abdominal wall muscles the oblique muscles responded with synergies related to fiber orientation, with women having higher amplitudes and more responsiveness to the lateral flexion moment than men. Synergies between the abdominal and back extensor sites as the moment demands change are discussed. These findings illustrate differential activation among erector spinae compartments and abdominal wall muscle sites supporting a highly organized pattern of response to bidirectional external moments with asynchronies more apparent in women. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Differential glucose uptake in quadriceps and other leg muscles during one-legged dynamic submaximal knee-extension exercise

    DEFF Research Database (Denmark)

    Kalliokoski, Kari K; Boushel, Robert; Langberg, Henning

    2011-01-01

    One-legged dynamic knee-extension exercise (DKE) is a widely used model to study the local cardiovascular and metabolic responses to exercise of the quadriceps muscles. In this study, we explored the extent to which different muscles of the quadriceps are activated during exercise using positron...... emission tomography (PET) determined uptake of [18F]-fluoro-deoxy-glucose (GU) during DKE. Five healthy male subjects performed DKE at 25 W for 35 min and both the contracting and contralateral resting leg were scanned with PET from mid-thigh and distally. On average, exercise GU was the highest...

  5. Comparative proteomic profiling of soleus, extensor digitorum longus, flexor digitorum brevis and interosseus muscles from the mdx mouse model of Duchenne muscular dystrophy.

    Science.gov (United States)

    Carberry, Steven; Brinkmeier, Heinrich; Zhang, Yaxin; Winkler, Claudia K; Ohlendieck, Kay

    2013-09-01

    Duchenne muscular dystrophy is due to genetic abnormalities in the dystrophin gene and represents one of the most frequent genetic childhood diseases. In the X-linked muscular dystrophy (mdx) mouse model of dystrophinopathy, different subtypes of skeletal muscles are affected to a varying degree albeit the same single base substitution within exon 23 of the dystrophin gene. Thus, to determine potential muscle subtype-specific differences in secondary alterations due to a deficiency in dystrophin, in this study, we carried out a comparative histological and proteomic survey of mdx muscles. We intentionally included the skeletal muscles that are often used for studying the pathomechanism of muscular dystrophy. Histological examinations revealed a significantly higher degree of central nucleation in the soleus and extensor digitorum longus muscles compared with the flexor digitorum brevis and interosseus muscles. Muscular hypertrophy of 20-25% was likewise only observed in the soleus and extensor digitorum longus muscles from mdx mice, but not in the flexor digitorum brevis and interosseus muscles. For proteomic analysis, muscle protein extracts were separated by fluorescence two-dimensional (2D) gel electrophoresis. Proteins with a significant change in their expression were identified by mass spectrometry. Proteomic profiling established an altered abundance of 24, 17, 19 and 5 protein species in the dystrophin-deficient soleus, extensor digitorum longus, flexor digitorum brevis and interosseus muscle, respectively. The key proteomic findings were verified by immunoblot analysis. The identified proteins are involved in the contraction-relaxation cycle, metabolite transport, muscle metabolism and the cellular stress response. Thus, histological and proteomic profiling of muscle subtypes from mdx mice indicated that distinct skeletal muscles are differentially affected by the loss of the membrane cytoskeletal protein, dystrophin. Varying degrees of perturbed protein

  6. Anatomía arterial de los colgajos musculares de extensor carpi radialis longus y extensor carpi radialis brevis para su uso en transferencia muscular funcional libre Arterial anatomy of the extensor carpi radialis longus and extensor carpi radialis brevis muscle flaps related to its use in free functioning muscle transfer

    Directory of Open Access Journals (Sweden)

    A. Rodríguez Lorenzo

    2008-09-01

    ón anatómica del nervio radial con el pedículo del ECRL hace que no sea posible su transferencia como colgajo libre sin sacrificar la rama motora del nervio radial en la mayor parte de los casos.The arterial anatomy of the Extensor Carpi Radialis Longus and Brevis (ECRL, ECRB flaps is herein described in order to provide the vascular basis to be used as free muscle transfer for facial reanimation. We used 29 fresh above-elbow human arms injected by means of two diferent techniques.Latex-injection was performed in 18 arms and the modified lead oxide-gelatine injection technique was performed in 11 arms. The ECRL and ECRB with their pedicles were dissected, photodocumented and radiographied.The number, length and calibers of the muscle pedicles were recorded. The intramuscular vascular pattern and the relations of the main pedicles of the muscles with the radial nerve were also noted. Two vascular patterns were found following the Mathes and Nahai Classification of the Vascular Anatomy of the Muscles (number of pedicles and its dominance: Type I (37,9% of ECRL and 20,7% of ECRB dissections and Type II (62,1% of ECRL and 79,3% of ECRB dissections. The dominant pedicle for the ECRL (with an average caliber of 1,73 mm and an average length of pedicle of 32,32 mm is a branch of the radial recurrent artery in 100% of the dissections and the dominant pedicle for the ECRB (with an average caliber of 1,11 mm and an average length of pedicle of 27,77 mm a branch of the radial artery in 68,9% of the dissections and a branch of radial recurrent artery in 31,1% of the cases. As a conclusion, ECRL and ECRB muscle flaps present two types of vascular patterns: type I and type II.Type II pattern is the most common in our study. The anatomical features of both muscles (vascular basis,presence of an important fascial layer, contour and length of the muscle, make them reliable as free muscles flaps for facial reanimation, however, the relation between the dominant pedicle for the ECRL

  7. Can a fatigue test of the isolated lumbar extensor muscles of untrained young men predict strength progression in a resistance exercise program?

    NARCIS (Netherlands)

    Helmhout, P.; Staal, B.; Dijk, J. van; Harts, C.; Bertina, F.; Bie, R. de

    2010-01-01

    AIM: The aim of this exploratory study was to investigate the predictive value of a fatigue test of the lumbar extensor muscles for training progression in a group of 28 healthy but predominantly sedentary male students, in an 8-week resistance exercise program. METHODS: A three-phased fatigue test

  8. Interdependence of torque, joint angle, angular velocity and muscle action during human multi-joint leg extension.

    Science.gov (United States)

    Hahn, Daniel; Herzog, Walter; Schwirtz, Ansgar

    2014-08-01

    Force and torque production of human muscles depends upon their lengths and contraction velocity. However, these factors are widely assumed to be independent of each other and the few studies that dealt with interactions of torque, angle and angular velocity are based on isolated single-joint movements. Thus, the purpose of this study was to determine force/torque-angle and force/torque-angular velocity properties for multi-joint leg extensions. Human leg extension was investigated (n = 18) on a motor-driven leg press dynamometer while measuring external reaction forces at the feet. Extensor torque in the knee joint was calculated using inverse dynamics. Isometric contractions were performed at eight joint angle configurations of the lower limb corresponding to increments of 10° at the knee from 30 to 100° of knee flexion. Concentric and eccentric contractions were performed over the same range of motion at mean angular velocities of the knee from 30 to 240° s(-1). For contractions of increasing velocity, optimum knee angle shifted from 52 ± 7 to 64 ± 4° knee flexion. Furthermore, the curvature of the concentric force/torque-angular velocity relations varied with joint angles and maximum angular velocities increased from 866 ± 79 to 1,238 ± 132° s(-1) for 90-50° knee flexion. Normalised eccentric forces/torques ranged from 0.85 ± 0.12 to 1.32 ± 0.16 of their isometric reference, only showing significant increases above isometric and an effect of angular velocity for joint angles greater than optimum knee angle. The findings reveal that force/torque production during multi-joint leg extension depends on the combined effects of angle and angular velocity. This finding should be accounted for in modelling and optimisation of human movement.

  9. Fatigue-related changes in motor-unit synchronization of quadriceps muscles within and across legs

    NARCIS (Netherlands)

    Boonstra, T.W.; Daffertshofer, A.; van Ditshuizen, J.C.; van den Heuvel, M.R.C.; Hofman, C.; Willigenburg, N.W.; Beek, P.J.

    2008-01-01

    Two experiments were conducted to examine effects of muscle fatigue on motor-unit synchronization of quadriceps muscles (rectus femoris, vastus medialis, vastus lateralis) within and between legs. We expected muscle fatigue to result in an increased common drive to different motor units of

  10. Possibility of leg muscle hypertrophy by ambulation in older adults: a brief review

    Directory of Open Access Journals (Sweden)

    Ozaki H

    2013-03-01

    Full Text Available Hayao Ozaki,1 Jeremy P Loenneke,2 Robert S Thiebaud,2 Joel M Stager,3 Takashi Abe31Juntendo University, Inzai, Chiba, Japan; 2Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA; 3Department of Kinesiology, Indiana University, Bloomington, IN, USAAbstract: It is known that ambulatory exercises such as brisk walking and jogging are potent stimuli for improving aerobic capacity, but it is less understood whether ambulatory exercise can increase leg muscle size and function. The purpose of this brief review is to discuss whether or not ambulatory exercise elicits leg muscle hypertrophy in older adults. Daily ambulatory activity with moderate (>3 metabolic equivalents [METs], which is defined as the ratio of the work metabolic rate to the resting metabolic rate intensity estimated by accelerometer is positively correlated with lower body muscle size and function in older adults. Although there is conflicting data on the effects of short-term training, it is possible that relatively long periods of walking, jogging, or intermittent running for over half a year can increase leg muscle size among older adults. In addition, slow-walk training with a combination of leg muscle blood flow restriction elicits muscle hypertrophy only in the blood flow restricted leg muscles. Competitive marathon running and regular high intensity distance running in young and middle-aged adults may not produce leg muscle hypertrophy due to insufficient recovery from the damaging running bout, although there have been no studies that have investigated the effects of running on leg muscle morphology in older subjects. It is clear that skeletal muscle hypertrophy can occur independently of exercise mode and load.Keywords: aerobic exercise, muscle mass, aging, strength, sarcopenia

  11. ALTERATION OF MUSCLE FUNCTION AFTER ELECTRICAL STIMULATION BOUT OF KNEE EXTENSORS AND FLEXORS

    Directory of Open Access Journals (Sweden)

    Marc Vanderthommen

    2012-12-01

    Full Text Available The purpose was to study the effects on muscle function of an electrical stimulation bout applied unilaterally on thigh muscles in healthy male volunteers. One group (ES group, n = 10 received consecutively 100 isometric contractions of quadriceps and 100 isometric contractions of hamstrings (on-off ratio 6-6 s induced by neuromuscular electrical stimulations (NMES. Changes in muscle torque, muscle soreness (0-10 VAS, muscle stiffness and serum creatine kinase (CK activity were assessed before the NMES exercise (pre-ex as well as 24h (d+1, 48h (d+2 and 120h (d+5 after the bout. A second group (control group, n = 10 were submitted to the same test battery than the ES group and with the same time-frame. The between-group comparison indicated a significant increase in VAS scores and in serum levels of CK only in the ES group. In the ES group, changes were more pronounced in hamstrings than in quadriceps and peaked at d+2 (quadriceps VAS scores = 2.20 ± 1.55 a.u. (0 at pre-ex; hamstrings VAS scores = 3.15 ± 2.14 a.u. (0 at pre-ex; hip flexion angle = 62 ± 5° (75 ± 6° at pre-ex; CK activity = 3021 ± 2693 IU·l-1 (136 ± 50 IU·l-1 at pre-ex. The results of the present study suggested the occurrence of muscle damage that could have been induced by the peculiar muscle recruitment in NMES and the resulting overrated mechanical stress. The sensitivity to the damaging effects of NMES appeared higher in the hamstrings than in quadriceps muscles

  12. Fibre type composition of soleus and extensor digitorum longus muscles in normal female inbred Lewis rats

    Czech Academy of Sciences Publication Activity Database

    Soukup, Tomáš; Zachařová, Gisela; Smerdu, V.

    2002-01-01

    Roč. 104, č. 4 (2002), s. 399-405 ISSN 0065-1281 R&D Projects: GA ČR GA304/00/1653 Grant - others:CZ - SI Czech-Slovenian Intergovernmental S&T Co-operation(XC) - Institutional research plan: CEZ:AV0Z5011922 Keywords : inbred Lewis rats * skeletal muscles * soleus and EDL muscles Subject RIV: FH - Neurology Impact factor: 0.867, year: 2002

  13. Effects of Constant and Doublet Frequency Electrical Stimulation Patterns on Force Production of Knee Extensor Muscles.

    Directory of Open Access Journals (Sweden)

    Carole Cometti

    Full Text Available This study compared knee extensors' neuromuscular fatigue in response to two 30-minute stimulation patterns: constant frequency train (CFT and doublet frequency train (DFT. Fifteen men underwent two separate sessions corresponding to each pattern. Measurements included torque evoked by each contraction and maximal voluntary contractions (MVC measured before and immediately after the stimulation sessions. In addition, activation level and torque evoked during doublets (Pd and tetanic contractions at 80-Hz (P80 and 20-Hz (P20 were determined in six subjects. Results indicated greater mean torque during the DFT stimulation session as compared with CFT. But, no difference was obtained between the two stimulation patterns for MVC and evoked torque decreases. Measurements conducted in the subgroup depicted a significant reduction of Pd, P20 and P80. Statistical analyses also revealed bigger P20 immediate reductions after CFT than after DFT. We concluded that DFT could be a useful stimulation pattern to produce and maintain greater force with quite similar fatigue than CFT.

  14. Back extensor muscle endurance test scores in coal miners in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, M.; Latimer, J.; Jamieson, M. [University of Sydney, Sydney, NSW (Australia). Faculty of Health and Science, School of Physiotherapy

    2003-06-01

    Low back pain is a common complaint among those working in the Australian coal mining industry. One test that may be predictive of first-time episodes of low back pain is the Biering-Sorensen test of back extensor endurance strength. While this test has been evaluated in overseas sedentary populations, normative data and the discriminative ability of the test have not been evaluated with coal miners. Eighty-eight coal miners completed a questionnaire for known risk factors for low back pain, performed the Biering-Sorensen test, and undertook a test of aerobic fitness. Data analysis was performed to describe the groups and to determine whether any significant difference existed between those with a past history of low back pain and those without. Significantly lower than expected holding times were found in this group of coal miners (mean 113 s). This result was significantly lower than demonstrated in previous studies. When holding times for those with a past history of low back pain were compared with times for those with no history of low back pain, the difference was not statistically significant, nor was there a significant difference in fitness between those with a past history of low back pain and those without. It is concluded that coal miners in Australia have lower than normal Biering-Sorensen holding times. This lower back holding time does not differ between coal miners with a past history of low back pain and those without.

  15. Decreased torque and electromyographic activity in the extensor thigh muscles in chondromalacia patellae.

    Science.gov (United States)

    Väätäinen, U; Airaksinen, O; Jaroma, H; Kiviranta, I

    1995-01-01

    The alterations in thigh muscle properties of chondromalacia patellae patients during isometric and dynamic endurance tests were studied using a variokinetic knee testing system linked to surface EMG. A total of 41 patients (chondromalacia group) with arthroscopically certified chondromalacia of the patella were studied. The control group consisted of 31 healthy adult volunteers with no history of knee pain or trauma. Peak torque values were 21% (p chondromalacia group than in the control group. The decrease in the ratio between integrated EMG (IEMG) and measured force were found in all parts of the quadriceps femoris muscle in patients with chondromalacia of the patella in isometric extension. No change in the normalized IEMG levels of the thigh muscles were found between chondromalacia patients and controls in dynamic endurance test. The severity of the chondromalacia of the patella did not affect the level of electromyographic activation in thigh muscles. The ratio of normalized EMG levels of vastus medialis and vastus lateralis did not differ between the groups. The present study showed that chondromalacia patellae patients have reduced force and electromyographic activation levels of quadriceps femoris muscle. Especially, the explosive strength of the quadriceps femoris muscle is reduced.

  16. [Statistical (Poisson) motor unit number estimation. Methodological aspects and normal results in the extensor digitorum brevis muscle of healthy subjects].

    Science.gov (United States)

    Murga Oporto, L; Menéndez-de León, C; Bauzano Poley, E; Núñez-Castaín, M J

    Among the differents techniques for motor unit number estimation (MUNE) there is the statistical one (Poisson), in which the activation of motor units is carried out by electrical stimulation and the estimation performed by means of a statistical analysis based on the Poisson s distribution. The study was undertaken in order to realize an approximation to the MUNE Poisson technique showing a coprehensible view of its methodology and also to obtain normal results in the extensor digitorum brevis muscle (EDB) from a healthy population. One hundred fourteen normal volunteers with age ranging from 10 to 88 years were studied using the MUNE software contained in a Viking IV system. The normal subjects were divided into two age groups (10 59 and 60 88 years). The EDB MUNE from all them was 184 49. Both, the MUNE and the amplitude of the compound muscle action potential (CMAP) were significantly lower in the older age group (page than CMAP amplitude ( 0.5002 and 0.4142, respectively pphisiology of the motor unit. The value of MUNE correlates better with the neuromuscular aging process than CMAP amplitude does.

  17. Lean and Obese Zucker Rat Extensor Digitorum Longus Muscle high-frequency electrical stimulation (HFES Data: Regulation of p70S6kinase Associated Proteins

    Directory of Open Access Journals (Sweden)

    Kevin M. Rice

    2018-02-01

    Full Text Available Anaerobic exercise has been advocated as a prescribed treatment for the management of diabetes: however, alterations in exercise-induced signaling remain largely unexplored in the diabetic muscle. Here, we compare the basal and the in situ contraction-induced phosphorylation of the AKT, GSK3beta, mTor, p70s6K, Pten, and Shp2 in the lean and obese (fa/fa Zucker rat Extensor Digitorum Longus (EDL muscle following a single bout of contractile stimuli. This article represents data associated with prior publications from our lab (Katta et al., 2009a, 2009b; Tullgren et al., 1991 [1–3] and concurrent Data in Brief articles (Ginjupalli et al., 2017a, 2017b; Rice et al., 2017a, 2017b [4–7]. Keywords: Diabetes, Skeletal muscle, High-frequency electrical stimulation (HFES, Zucker rat, Extensor Digitorum Longus, p70s6k

  18. Bed rest attenuates sympathetic and pressor responses to isometric exercise in antigravity leg muscles in humans.

    Science.gov (United States)

    Kamiya, Atsunori; Michikami, Daisaku; Shiozawa, Tomoki; Iwase, Satoshi; Hayano, Junichiro; Kawada, Toru; Sunagawa, Kenji; Mano, Tadaaki

    2004-05-01

    Although spaceflight and bed rest are known to cause muscular atrophy in the antigravity muscles of the legs, the changes in sympathetic and cardiovascular responses to exercises using the atrophied muscles remain unknown. We hypothesized that bed rest would augment sympathetic responses to isometric exercise using antigravity leg muscles in humans. Ten healthy male volunteers were subjected to 14-day 6 degrees head-down bed rest. Before and after bed rest, they performed isometric exercises using leg (plantar flexion) and forearm (handgrip) muscles, followed by 2-min postexercise muscle ischemia (PEMI) that continues to stimulate the muscle metaboreflex. These exercises were sustained to fatigue. We measured muscle sympathetic nerve activity (MSNA) in the contralateral resting leg by microneurography. In both pre- and post-bed-rest exercise tests, exercise intensities were set at 30 and 70% of the maximum voluntary force measured before bed rest. Bed rest attenuated the increase in MSNA in response to fatiguing plantar flexion by approximately 70% at both exercise intensities (both P antigravity leg muscles.

  19. Aberrant femoral torsion presenting with frog-leg squatting mimicking gluteal muscle contracture.

    Science.gov (United States)

    Chiang, Chia-Ling; Tsai, Meng-Yuan; Chang, Wei-Ning; Chen, Clement Kuen-Huang

    2012-04-01

    Patients with frog-leg squatting have restricted internal rotation and adduction of the affected hips during sitting or squatting. In the surgical literature, the cause generally has been presumed to arise from and be pathognomonic for gluteal muscle contracture. However, we have encountered patients with frog-leg squatting but without gluteal muscle contracture. We therefore raised the following questions: What are the imaging features of patients with frog-leg squatting? Do conditions other than gluteal muscle contracture manifest frog-leg squatting? We retrospectively reviewed the MR images of 67 patients presenting with frog-leg squatting from April 1998 to July 2010. There were four females and 63 males; their mean age was 22.2 years (range, 4-50 years). During MRI readout, we observed aberrant axes of some femoral necks and obtained additional CT to measure femoral torsion angles in 59 of the 67 patients. MR images of 27 (40%) patients had signs of gluteal muscle contracture. Twenty-two (33%) patients (40 femora) had aberrant femoral torsion, including diminished anteversion (range, 6°-0°; average, 3.9°) in 11 femora of eight patients and femoral retroversion (range, muscle contracture or aberrant femoral torsion. The observation of aberrant femoral torsion was not anticipated before imaging studies. In addition to gluteal muscle contracture, aberrant femoral torsion can be a cause of frog-leg squatting. Level II, diagnostic study. See the guidelines for Authors for a complete description of levels of evidence.

  20. Comparing two methods to record maximal voluntary contractions and different electrode positions in recordings of forearm extensor muscle activity: Refining risk assessments for work-related wrist disorders.

    Science.gov (United States)

    Dahlqvist, Camilla; Nordander, Catarina; Granqvist, Lothy; Forsman, Mikael; Hansson, Gert-Åke

    2018-01-01

    Wrist disorders are common in force demanding industrial repetitive work. Visual assessment of force demands have a low reliability, instead surface electromyography (EMG) may be used as part of a risk assessment for work-related wrist disorders. For normalization of EMG recordings, a power grip (hand grip) is often used as maximal voluntary contraction (MVC) of the forearm extensor muscles. However, the test-retest reproducibility is poor and EMG amplitudes exceeding 100% have occasionally been recorded during work. An alternative MVC is resisted wrist extension, which may be more reliable. To compare hand grip and resisted wrist extension MVCs, in terms of amplitude and reproducibility, and to examine the effect of electrode positioning. Twelve subjects participated. EMG from right forearm extensors, from four electrode pairs, was recorded during MVCs, on three separate occasions. The group mean EMG amplitudes for resisted wrist extension were 1.2-1.7 times greater than those for hand grip. Resisted wrist extension showed better reproducibility than hand grip. The results indicate that the use of resisted wrist extension is a more accurate measurement of maximal effort of wrist extensor contractions than using hand grip and should increase the precision in EMG recordings from forearm extensor muscles, which in turn will increase the quality of risk assessments that are based on these.

  1. THE ROLE OF LEG AND TRUNK MUSCLES PROPRIOCEPTION ON STATIC AND DYNAMIC POSTURAL CONTROL

    Directory of Open Access Journals (Sweden)

    SEYED Hossein Hosseinimehr

    2010-04-01

    Full Text Available The proprioception information is a prerequisite for balance, body’s navigation system, and the movement coordinator. Due to changes between the angles of ankle, knee, and hip joints the aforementioned information are important in the coordination of the limbs and postural balance. The aim of this study was to investigate therole of leg and trunk muscles proprioception on static and dynamic postural control. Thirty males students of physical education and sport sciences (age =21.23 ± 2.95 years, height = 170.4 ± 5.1 cm, and weight = 70.7 ± 5.6 kg participated in this study volunteered. Vibration (100HZ was used to disturb of proprioception. Vibrationoperated on leg muscle (gasterocnemius and trunk muscles (erector spine muscle, at L1 level. Leg stance time and Star Excursion Balance Test were used for evaluation of static and dynamic postural control respectively.Subjects performed pre and post (with operated vibration leg stance time and star excursion balance test. Paired sample test used for investigation the effect of vibration on leg and trunk muscles in static and dynamic postural control. Result of this study showed in static postural control, there is no significant difference between pre and post test (operated vibration in leg and trunk muscles (p≤0.05. In contrast there is significant difference indynamic postural control between pre and post test in leg muscles in 8 directions of star excursion balance test (p≤0.05 while there is only significant difference in trunk muscle in antrolateral and lateral of star excursion balance test (p≤0.05. During physical training such conditions like fatigue and injury can disturbproprioceptions’ information. Thus, due to the importance of this information we recommend that coaches'additionally specific trainings any sport used specific exercises to enhance the proprioception information

  2. Extensor Tendon Injuries

    Science.gov (United States)

    ... All Topics A-Z Videos Infographics Symptom Picker Anatomy Bones Joints Muscles Nerves Vessels Tendons About Hand Surgery What is a Hand Surgeon? What is a Hand Therapist? Media Find a Hand Surgeon Home Anatomy Extensor Tendon Injuries Email to a friend * required ...

  3. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    Science.gov (United States)

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect–machine hybrid legged robot). PMID:25140875

  4. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Directory of Open Access Journals (Sweden)

    Feng Cao

    Full Text Available In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot.

  5. Corticospinal excitability of the ankle extensor muscles is enhanced in ballet dancers.

    Science.gov (United States)

    Saito, Sakiko; Obata, Hiroki; Endoh, Takashi; Kuno-Mizumura, Mayumi; Nakazawa, Kimitaka

    2014-09-01

    We tested the corticospinal excitability of the soleus muscle in ballet dancers to clarify whether the presumed long-term repetition of the specific plantarflexion results in changes of excitability in this neural pathway. We compared motor evoked potentials of the soleus muscle at rest and during isometric contraction of the plantar flexors in dancers and non-dancers. The amplitudes of motor evoked potentials elicited by transcranial magnetic stimulation during contraction were examined against the background electromyographic activity. A regression line was calculated for each subject. Results showed that the slope of the regression line is significantly greater in the dancer group than in the control group, suggesting that the corticospinal tract of ballet dancers has adapted to long-term repetition of plantarflexion in daily ballet training.

  6. Creatine Loading Does Not Preserve Muscle Mass or Strength During Leg Immobilization in Healthy, Young Males

    NARCIS (Netherlands)

    Backx, Evelien M.P.; Hangelbroek, Roland; Snijders, Tim; Verscheijden, Marie Louise; Verdijk, Lex B.; Groot, de Lisette C.P.G.M.; Loon, van Luc J.C.

    2017-01-01

    Background: A short period of leg immobilization leads to rapid loss of muscle mass and strength. Creatine supplementation has been shown to increase lean body mass in active individuals and can be used to augment gains in muscle mass and strength during prolonged resistance-type exercise

  7. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    OpenAIRE

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, ...

  8. Normal mitochondrial function and increased fat oxidation capacity in leg and arm muscles in obese humans

    DEFF Research Database (Denmark)

    Ara, I; Larsen, S; Stallknecht, Bente Merete

    2011-01-01

    was that fat oxidation during exercise might be differentially preserved in leg and arm muscles after weight loss.Methods:Indirect calorimetry was used to calculate fat and carbohydrate oxidation during both progressive arm-cranking and leg-cycling exercises. Muscle biopsy samples were obtained from musculus...... deltoideus (m. deltoideus) and m. vastus lateralis muscles. Fibre-type composition, enzyme activity and O(2) flux capacity of saponin-permeabilized muscle fibres were measured, the latter by high-resolution respirometry.Results:During the graded exercise tests, peak fat oxidation during leg cycling...... and the relative workload at which it occurred (FatMax) were higher in PO and O than in C. During arm cranking, peak fat oxidation was higher in O than in C, and FatMax was higher in O than in PO and C. Similar fibre-type composition was found between groups. Plasma adiponectin was higher in PO than in C and O...

  9. Leg blood flow is impaired during small muscle mass exercise in patients with COPD

    DEFF Research Database (Denmark)

    Iepsen, Ulrik Winning; Munch, Gregers Druedal Wibe; Rugbjerg, Mette

    2017-01-01

    to both endothelium-independent (SNP) and endothelium-dependent (ACh) stimulation. The results suggests that leg muscle blood flow is impaired during small muscle mass exercise in patients with COPD possibly due to impaired formation of prostacyclin and increased levels of endothelin-1.......Skeletal muscle blood flow is regulated to match the oxygen demand and dysregulation could contribute to exercise intolerance in patients with COPD. We measured leg hemodynamics and metabolites from vasoactive compounds in muscle interstitial fluid and plasma at rest, during one-legged knee...... the formation of interstitial prostacyclin (vasodilator) was only increased in the controls. There was no difference between groups in the nitrite/nitrate levels (vasodilator) in plasma or interstitial fluid during exercise. Moreover, patients and controls showed similar vasodilatory capacity in response...

  10. Arm and leg substrate utilization and muscle adaptation after prolonged low-intensity training

    DEFF Research Database (Denmark)

    Helge, Jørn Wulff

    2010-01-01

    This review will focus on current data where substrate metabolism in arm and leg muscle is investigated and discuss the presence of higher carbohydrate oxidation and lactate release observed during arm compared with leg exercise. Furthermore, a basis for a possible difference in substrate partiti...... at comparable workloads. Finally, the influence and capacity of low-intensity training to influence metabolic fitness in the face of a limited effect on aerobic fitness will be challenged....... partitioning between endogenous and exogenous substrate during arm and leg exercise will be debated. Moreover the review will probe if differences between arm and leg muscle are merely a result of different training status rather than a qualitative difference in limb substrate regulation. Along this line...... the review will address the available studies on low-intensity training performed separately with arm or legs or as whole-body training to evaluate if this leads to different adaptations in arm and leg muscle resulting in different substrate utilization patterns during separate arm or leg exercise...

  11. Muscle interstitial ATP and norepinephrine concentrations in the human leg during exercise and ATP infusion

    DEFF Research Database (Denmark)

    Mortensen, Stefan P.; Gonzalez-Alonso, Jose; Nielsen, Jens Jung

    2009-01-01

    ATP and NE concentrations to gain insight into the interstitial and intravascular mechanisms by which ATP causes muscle vasodilation and sympatholysis. Leg hemodynamics and muscle interstitial nucleotide and norepinephrine (NE) concentrations were measured during: 1) femoral arterial ATP infusion (0......, respectively (Pcontracting muscle (Pmuscle, whereas interstitial NE concentrations increased similarly in both active...... and inactive muscles. These results suggest that the vasodilatory and sympatholytic effects of intraluminal ATP are mainly mediated via endothelial prinergic receptors. Intraluminal ATP and muscle contractions appear to modulate sympathetic nerve activity by inhibiting the effect of NE rather than blunting its...

  12. Optimizing the Distribution of Leg Muscles for Vertical Jumping.

    Directory of Open Access Journals (Sweden)

    Jeremy D Wong

    Full Text Available A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas-which determine the maximum force deliverable by the muscles-constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of

  13. Optimizing the Distribution of Leg Muscles for Vertical Jumping

    Science.gov (United States)

    Wong, Jeremy D.; Bobbert, Maarten F.; van Soest, Arthur J.; Gribble, Paul L.; Kistemaker, Dinant A.

    2016-01-01

    A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas—which determine the maximum force deliverable by the muscles—constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of the skeletal

  14. Recovery of atrophic leg muscles in the hemiplegics due to cerebrovascular accidents

    International Nuclear Information System (INIS)

    Odajima, Natsu; Ishiai, Sumio; Okiyama, Ryouichi; Furukawa, Tetsuo; Tsukagoshi, Hiroshi.

    1988-01-01

    Thirty-five patients with hemiplegia due to cerebrovascular accidents were studied with regared to the muscle wastings before and after rehabilitation training. Hemiplegics were composed of 12 improved and 23 non-improved patients. The CT scan was carried out at the midportion of the thigh and largest-diameter section of the calf. Muscle size of each cross-sectional area was measured on CT image and the increase of size (ΔS) in each muscle after training was calculated. The ΔS of quadriceps femoris was correlated with that of whole cross-section of the thigh. The gracilis in non-affected side was not correlated with that of whole muscles. In both legs, there was an increase in leg muscle size after training. These changes were nost marked in the non-affected side of the improved patients. After training the difference between the two limbs remained unchanged. Recovery of muscle wasting in both legs was seen first in the quadriceps in thigh and flexors in calf. Gracilis was relatively unchanged in comparison with other muscles. Remarkable increase of muscle size in non-affected side was worthwhile to note. (author)

  15. Recovery of atrophic leg muscles in the hemiplegics due to cerebrovascular accidents. Computed tomographic study

    Energy Technology Data Exchange (ETDEWEB)

    Odajima, Natsu; Ishiai, Sumio; Okiyama, Ryouichi; Furukawa, Tetsuo; Tsukagoshi, Hiroshi.

    1988-02-01

    Thirty-five patients with hemiplegia due to cerebrovascular accidents were studied with regared to the muscle wastings before and after rehabilitation training. Hemiplegics were composed of 12 improved and 23 non-improved patients. The CT scan was carried out at the midportion of the thigh and largest-diameter section of the calf. Muscle size of each cross-sectional area was measured on CT image and the increase of size (..delta..S) in each muscle after training was calculated. The ..delta..S of quadriceps femoris was correlated with that of whole cross-section of the thigh. The gracilis in non-affected side was not correlated with that of whole muscles. In both legs, there was an increase in leg muscle size after training. These changes were nost marked in the non-affected side of the improved patients. After training the difference between the two limbs remained unchanged. Recovery of muscle wasting in both legs was seen first in the quadriceps in thigh and flexors in calf. Gracilis was relatively unchanged in comparison with other muscles. Remarkable increase of muscle size in non-affected side was worthwhile to note.

  16. Loss of knee extensor torque complexity during fatiguing isometric muscle contractions occurs exclusively above the critical torque.

    Science.gov (United States)

    Pethick, Jamie; Winter, Samantha L; Burnley, Mark

    2016-06-01

    The complexity of knee extensor torque time series decreases during fatiguing isometric muscle contractions. We hypothesized that because of peripheral fatigue, this loss of torque complexity would occur exclusively during contractions above the critical torque (CT). Nine healthy participants performed isometric knee extension exercise (6 s of contraction, 4 s of rest) on six occasions for 30 min or to task failure, whichever occurred sooner. Four trials were performed above CT (trials S1-S4, S1 being the lowest intensity), and two were performed below CT (at 50% and 90% of CT). Global, central, and peripheral fatigue were quantified using maximal voluntary contractions (MVCs) with femoral nerve stimulation. The complexity of torque output was determined using approximate entropy (ApEn) and the detrended fluctuation analysis-α scaling exponent (DFA-α). The MVC torque was reduced in trials below CT [by 19 ± 4% (means ± SE) in 90%CT], but complexity did not decrease [ApEn for 90%CT: from 0.82 ± 0.03 to 0.75 ± 0.06, 95% paired-samples confidence intervals (CIs), 95% CI = -0.23, 0.10; DFA-α from 1.36 ± 0.01 to 1.32 ± 0.03, 95% CI -0.12, 0.04]. Above CT, substantial reductions in MVC torque occurred (of 49 ± 8% in S1), and torque complexity was reduced (ApEn for S1: from 0.67 ± 0.06 to 0.14 ± 0.01, 95% CI = -0.72, -0.33; DFA-α from 1.38 ± 0.03 to 1.58 ± 0.01, 95% CI 0.12, 0.29). Thus, in these experiments, the fatigue-induced loss of torque complexity occurred exclusively during contractions performed above the CT. Copyright © 2016 the American Physiological Society.

  17. Factors associated with upper leg muscle strength in knee osteoarthritis: A scoping review

    Directory of Open Access Journals (Sweden)

    Arjan H de Zwart

    2017-11-01

    Full Text Available Objective: Muscle weakness is common and strongly related to clinical outcome in patients with knee or hip osteoarthritis. To date, there is no clear overview of the information on factors associated with muscle strength in knee and hip osteoarthritis. The aim of this paper is to provide an overview of current knowledge on factors associated with upper leg muscle strength in this population. Design: The framework of a scoping review was chosen. MEDLINE database was searched systematically up to 22 April 2017. Studies that described a relationship between a factor and muscle strength in knee or hip osteoarthritis were included. Results: A total of 65 studies met the inclusion criteria. In studies of knee osteoarthritis, 4 factors were consistently found to be associated with lower muscle strength. Due to the low number of studies on hip osteoarthritis no conclusions could be drawn on associations. Conclusion: Lower muscle quality, physical inactivity, more severe joint degeneration, and higher pain are reported to be associated with lower strength in the upper leg muscles in knee osteoarthritis. Future research into knee osteoarthritis should focus on other potential determinants of muscle strength, such as muscle quantity, muscle activation, nutrition and vitamins, and inflammation. In hip osteoarthritis, more research is needed into all potential determinants.

  18. Bilateral differences in muscle fascicle architecture are not related to the preferred leg in jumping athletes.

    Science.gov (United States)

    Aeles, Jeroen; Lenchant, Sietske; Vanlommel, Liesbeth; Vanwanseele, Benedicte

    2017-07-01

    In many sports, athletes have a preferred leg for sport-specific tasks, such as jumping, which leads to strength differences between both legs, yet the underlying changes in force-generating mechanical properties of the muscle remain unknown. The purpose of this study was to investigate whether the muscle architecture of the medial gastrocnemius (MG) is different between both legs in well-trained jumping athletes and untrained individuals. In addition, we investigated the effect of two ankle joint positions on ultrasound muscle architecture measurements. Muscle architecture of both legs was measured in 16 athletes and 11 untrained individuals at two ankle joint angles: one with the ankle joint in a tendon slack length (TSL) angle and one in a 90° angle. Fascicle lengths and pennation angles at TSL were not different between the preferred and non-preferred legs in either group. The comparison between groups showed no difference in fascicle length, but greater pennation angles were found in the athletes (21.7° ± 0.5°) compared to the untrained individuals (19.8° ± 0.6°). Analyses of the muscle architecture at a 90° angle yielded different results, mainly in the comparison between groups. These results provide only partial support for the notion of training-induced changes in muscle architecture as only differences in pennation angles were found between athletes and untrained individuals. Furthermore, our results provide support to the recommendation to take into account the tension-length relationship and to measure muscle architecture at individually determined tendon slack joint angles.

  19. Regulation of PDH in human arm and leg muscles at rest and during intense exercise

    DEFF Research Database (Denmark)

    Kiilerich, Kristian; Birk, Jesper Bratz; Damsgaard, Rasmus

    2008-01-01

    To test the hypothesis that pyruvate dehydrogenase (PDH) is differentially regulated in specific human muscles, regulation of PDH was examined in triceps, deltoid, and vastus lateralis at rest and during intense exercise. To elicit considerable glycogen use, subjects performed 30 min of exhaustive...... arm cycling on two occasions and leg cycling exercise on a third day. Muscle biopsies were obtained from deltoid or triceps on the arm exercise days and from vastus lateralis on the leg cycling day. Resting PDH protein content and phosphorylation on PDH-E1 alpha sites 1 and 2 were higher (P ....05) in vastus lateralis than in triceps and deltoid as was the activity of oxidative enzymes. Net muscle glycogen utilization was similar in vastus lateralis and triceps ( approximately 50%) but less in deltoid (likely reflecting less recruitment of deltoid), while muscle lactate accumulation was approximately...

  20. Skeletal muscle glucose uptake during dynamic exercise in humans

    DEFF Research Database (Denmark)

    Richter, Erik; Kiens, Bente; Saltin, Bengt

    1988-01-01

    uptake was not compensated for by increased uptake of free fatty acids but was accompanied by decreases in plasma insulin and increases in plasma epinephrine and norepinephrine. During work with large muscle masses, arterial lactate increased to approximately 6 mM, and net leg lactate release reverted......To study the role of muscle mass in glucoregulation, six subjects worked with the knee extensors of one leg on a specially constructed cycle ergometer. The knee extensors of one leg worked either alone or in combination with the knee extensors of the other leg and/or with the arms. Substrate usage...... to net lactate uptake. Decreased glucose uptake could not be explained by decreased perfusion. It is concluded that thigh muscle glucose uptake is affected by the size of the total muscle mass engaged in exercise. The decrease in thigh glucose uptake, when arm cranking was added and O2 uptake...

  1. Are substrate use during exercise and mitochondrial respiratory capacity decreased in arm and leg muscle in type 2 diabetes?

    DEFF Research Database (Denmark)

    Larsen, Steen; Ara, I; Rabøl, R

    2009-01-01

    and carbohydrate oxidation during both progressive arm-cranking and leg-cycling exercises. Muscle biopsies from arm and leg were obtained. Fibre type, as well as O(2) flux capacity of saponin-permeabilised muscle fibres were measured, the latter by high resolution respirometry, in patients with type 2 diabetes...

  2. Hemodynamic Changes in Rat Leg Muscles during Tourniquet-induced Ischemia-reperfusion Injury Observed by Near-infrared Spectroscopy

    Science.gov (United States)

    2009-07-01

    leg muscle during pressure increase (Arbabi et al 1999) and in the human leg muscle during exercise (Breit et al 1997, Egun et al 2002, van den Brand...time of flight measurement. Phys Med Biol 1988;33:1433–42. [PubMed: 3237772] Egun A, Farooq V, Torella F, Cowley R, Thorniley MS, McCollum CN. The

  3. Predicting muscle forces during the propulsion phase of single leg triple hop test.

    Science.gov (United States)

    Alvim, Felipe Costa; Lucareli, Paulo Roberto Garcia; Menegaldo, Luciano Luporini

    2018-01-01

    Functional biomechanical tests allow the assessment of musculoskeletal system impairments in a simple way. Muscle force synergies associated with movement can provide additional information for diagnosis. However, such forces cannot be directly measured noninvasively. This study aims to estimate muscle activations and forces exerted during the preparation phase of the single leg triple hop test. Two different approaches were tested: static optimization (SO) and computed muscle control (CMC). As an indirect validation, model-estimated muscle activations were compared with surface electromyography (EMG) of selected hip and thigh muscles. Ten physically healthy active women performed a series of jumps, and ground reaction forces, kinematics and EMG data were recorded. An existing OpenSim model with 92 musculotendon actuators was used to estimate muscle forces. Reflective markers data were processed using the OpenSim Inverse Kinematics tool. Residual Reduction Algorithm (RRA) was applied recursively before running the SO and CMC. For both, the same adjusted kinematics were used as inputs. Both approaches presented similar residuals amplitudes. SO showed a closer agreement between the estimated activations and the EMGs of some muscles. Due to inherent EMG methodological limitations, the superiority of SO in relation to CMC can be only hypothesized. It should be confirmed by conducting further studies comparing joint contact forces. The workflow presented in this study can be used to estimate muscle forces during the preparation phase of the single leg triple hop test and allows investigating muscle activation and coordination. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Blood pressure and the contractility of a human leg muscle.

    Science.gov (United States)

    Luu, Billy L; Fitzpatrick, Richard C

    2013-11-01

    These studies investigate the relationships between perfusion pressure, force output and pressor responses for the contracting human tibialis anterior muscle. Eight healthy adults were studied. Changing the height of tibialis anterior relative to the heart was used to control local perfusion pressure. Electrically stimulated tetanic force output was highly sensitive to physiological variations in perfusion pressure showing a proportionate change in force output of 6.5% per 10 mmHg. This perfusion-dependent change in contractility begins within seconds and is reversible with a 53 s time constant, demonstrating a steady-state equilibrium between contractility and perfusion pressure. These stimulated contractions did not produce significant cardiovascular responses, indicating that the muscle pressor response does not play a major role in cardiovascular regulation at these workloads. Voluntary contractions at forces that would require constant motor drive if perfusion pressure had remained constant generated a central pressor response when perfusion pressure was lowered. This is consistent with a larger cortical drive being required to compensate for the lost contractility with lower perfusion pressure. The relationship between contractility and perfusion for this large postural muscle was not different from that of a small hand muscle (adductor pollicis) and it responded similarly to passive peripheral and active central changes in arterial pressure, but extended over a wider operating range of pressures. If we consider that, in a goal-oriented motor task, muscle contractility determines central motor output and the central pressor response, these results indicate that muscle would fatigue twice as fast without a pressor response. From its extent, timing and reversibility we propose a testable hypothesis that this change in contractility arises through contraction- and perfusion-dependent changes in interstitial K(+) concentration.

  5. Leg muscle activation during gait in Parkinson's disease : Adaptation and interlimb coordination

    NARCIS (Netherlands)

    Dietz, [No Value; Zijlstra, W; Prokop, T; Berger, W

    1995-01-01

    Adaptation in leg muscle activity and coordination between lower limbs were studied during walking on a treadmill with split belts in one group of parkinsonian patients and one of age-matched healthy subjects. Four different belt speeds (0.25/0.5/0.75/1.0 m/sec) were applied in selected combinations

  6. Quantitation of progressive muscle fatigue during dynamic leg exercise in humans

    DEFF Research Database (Denmark)

    Fulco, C S; Lewis, S F; Frykman, Peter

    1995-01-01

    , a product of a contraction rate (1 Hz), force measured at the ankle, and distance of ankle movement from 90 degrees to 150 degrees of KE, was precisely controlled. Lack of rise in myoelectric activity in biceps femoris of the active leg during DKE and MVC was consistent with restriction of muscle action...

  7. Dissociation between lactate and proton exchange in muscle during intense exercise in man

    DEFF Research Database (Denmark)

    Bangsbo, Jens; Juel, Carsten; Hellsten, Ylva

    1997-01-01

    1. Transport of lactate, H+ and fluid across muscle sarcolemma was studied in contracting muscles under varying blood acid-base conditions. 2. Subjects performed two-legged submaximal knee-extensor exercise for 29-35 min consisting of warming up for 5 min followed by 10 min of leg exercise (L1...

  8. Muscle power is an independent determinant of pain and quality of life in knee osteoarthritis

    Science.gov (United States)

    OBJECTIVE: This study examined the relationships between leg muscle strength, power, and perceived disease severity in subjects with knee osteoarthritis (OA) in order to determine whether dynamic leg extensor muscle power would be associated with pain and quality of life in knee OA. METHODS: Baseli...

  9. Toe blood pressure and leg muscle oxygenation with body posture.

    Science.gov (United States)

    Rosales-Velderrain, Armando; Cardno, Michael; Mateus, Jaime; Kumar, Ravindra; Schlabs, Thomas; Hargens, Alan R

    2011-05-01

    In 1980 Katkov and Chestukhin measured blood pressures and oxygenation invasively at various body tilt angles at different locations on the body, including the foot. To our knowledge, such measurements have not been performed noninvasively. Therefore, the purpose of this study was to measure toe blood pressure (TBP) and lower limb muscle oxygenation noninvasively at various body tilt angles, and to assess the use of a Finometer for noninvasive TBP measurements. Our noninvasive results are compared with those performed by Katkov and Chestukhin. We hypothesized that: 1) the Finometer provides a noninvasive measurement of TBP at different tilt angles; and 2) muscle oxygenation is highest with 0 and -6 degrees, and decreases with increased head-up tilt (HUT). There were 10 subjects who were exposed to different body tilt angles (-6, 0, 10, 30, 70, and 90 degrees). At each angle we measured TBP noninvasively with a Finometer and muscle tissue oxygenation by near infrared spectroscopy. We found a strong correlation between TBP using the Finometer and TBP predicted by adding the hydrostatic component due to body tilt to the standard arm blood pressure measurement. At 10, 30, 70, and 90 degrees both TBP and tissue oxygenation were significantly different from the 0 degree (supine) level. Oxygenation decreased and TBP increased with higher HUT angles. No differences were observed in TBP or oxygenation between -6 and 0 degree. The Finometer accurately measures TBP noninvasively with body tilt. Also, muscle oxygenation is highest at small HUT angles and decreases with increased HUT.

  10. Relationship between the Modified Modified Ashworth Scale and the Biomechanical Measure in Assessing Knee Extensor Muscle Spasticity in Patients with Post-Stroke Hemiparesia:A Pilot Study

    Directory of Open Access Journals (Sweden)

    N. Nakhostin Ansari

    2014-07-01

    Full Text Available Introduction & Objective: The Modified Modified Ashworth Scale (MMAS is a clinical meas-ure that has been recently developed for the assessment of muscle spasticity. There is a dearth of research on the validity of the MMAS. The aim of the present study was to investi-gate the relationship between the MMAS and the biomechanical measure of work-velocity slope in assessing knee extensor muscle spasticity in patients with hemiparesia. Materials & Methods: Fourteen patients with post-stroke hemiparesia were included in this cross sectional study. Knee extensor spasticity was assessed with MMAS. An isokinetic dy-namometer was used to impose knee passive flexion with the angular velocity of 10, 30, 60, and 90 °/Sec to measure Torque-angle data. Work (Joule was calculated at each velocity to determine the slope of the work-velocity curves as the biomechanical measure of muscle spasticity. Results: The mean work decreased as the velocity increased but was not statistically signifi-cant (P = 0.07. The mean slope was – 0.35 [J /(°/Sec]. There was no significant correlation between the MMAS and the work-velocity slope (r =0.31, P = 0.28. Conclusion: There was no significant relationship between the MMAS and the biomechanical measure of work-velocity slope. Further studies with larger sample size are suggested. (Sci J Hamadan Univ Med Sci 2014; 21 (2: 131-136

  11. Coordinated development of muscles and tendon-like structures: early interactions in the Drosophila leg

    Directory of Open Access Journals (Sweden)

    cedric esoler

    2016-02-01

    Full Text Available The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates during the early steps of leg development, we affect the spatial localisation of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes.

  12. Human Leg Model Predicts Muscle Forces, States, and Energetics during Walking.

    Science.gov (United States)

    Markowitz, Jared; Herr, Hugh

    2016-05-01

    Humans employ a high degree of redundancy in joint actuation, with different combinations of muscle and tendon action providing the same net joint torque. Both the resolution of these redundancies and the energetics of such systems depend on the dynamic properties of muscles and tendons, particularly their force-length relations. Current walking models that use stock parameters when simulating muscle-tendon dynamics tend to significantly overestimate metabolic consumption, perhaps because they do not adequately consider the role of elasticity. As an alternative, we posit that the muscle-tendon morphology of the human leg has evolved to maximize the metabolic efficiency of walking at self-selected speed. We use a data-driven approach to evaluate this hypothesis, utilizing kinematic, kinetic, electromyographic (EMG), and metabolic data taken from five participants walking at self-selected speed. The kinematic and kinetic data are used to estimate muscle-tendon lengths, muscle moment arms, and joint moments while the EMG data are used to estimate muscle activations. For each subject we perform an optimization using prescribed skeletal kinematics, varying the parameters that govern the force-length curve of each tendon as well as the strength and optimal fiber length of each muscle while seeking to simultaneously minimize metabolic cost and maximize agreement with the estimated joint moments. We find that the metabolic cost of transport (MCOT) values of our participants may be correctly matched (on average 0.36±0.02 predicted, 0.35±0.02 measured) with acceptable joint torque fidelity through application of a single constraint to the muscle metabolic budget. The associated optimal muscle-tendon parameter sets allow us to estimate the forces and states of individual muscles, resolving redundancies in joint actuation and lending insight into the potential roles and control objectives of the muscles of the leg throughout the gait cycle.

  13. Human Leg Model Predicts Muscle Forces, States, and Energetics during Walking.

    Directory of Open Access Journals (Sweden)

    Jared Markowitz

    2016-05-01

    Full Text Available Humans employ a high degree of redundancy in joint actuation, with different combinations of muscle and tendon action providing the same net joint torque. Both the resolution of these redundancies and the energetics of such systems depend on the dynamic properties of muscles and tendons, particularly their force-length relations. Current walking models that use stock parameters when simulating muscle-tendon dynamics tend to significantly overestimate metabolic consumption, perhaps because they do not adequately consider the role of elasticity. As an alternative, we posit that the muscle-tendon morphology of the human leg has evolved to maximize the metabolic efficiency of walking at self-selected speed. We use a data-driven approach to evaluate this hypothesis, utilizing kinematic, kinetic, electromyographic (EMG, and metabolic data taken from five participants walking at self-selected speed. The kinematic and kinetic data are used to estimate muscle-tendon lengths, muscle moment arms, and joint moments while the EMG data are used to estimate muscle activations. For each subject we perform an optimization using prescribed skeletal kinematics, varying the parameters that govern the force-length curve of each tendon as well as the strength and optimal fiber length of each muscle while seeking to simultaneously minimize metabolic cost and maximize agreement with the estimated joint moments. We find that the metabolic cost of transport (MCOT values of our participants may be correctly matched (on average 0.36±0.02 predicted, 0.35±0.02 measured with acceptable joint torque fidelity through application of a single constraint to the muscle metabolic budget. The associated optimal muscle-tendon parameter sets allow us to estimate the forces and states of individual muscles, resolving redundancies in joint actuation and lending insight into the potential roles and control objectives of the muscles of the leg throughout the gait cycle.

  14. Fatty infiltrate in the cervical extensor muscles is not a feature of chronic, insidious-onset neck pain

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, J. [Division of Physiotherapy, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane (Australia); Department of Physical Therapy, Rueckert-Hartman School for Health Professions, Regis University, Denver, Colorado (United States); Centre for Magnetic Resonance, University of Queensland, Brisbane (Australia)], E-mail: jelltt@regis.edu; Sterling, M. [Division of Physiotherapy, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane (Australia); Noteboom, J.T. [Department of Physical Therapy, Rueckert-Hartman School for Health Professions, Regis University, Denver, Colorado (United States); Darnell, R. [Division of Physiotherapy, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane (Australia); Galloway, G. [Centre for Magnetic Resonance, University of Queensland, Brisbane (Australia); Jull, G. [Division of Physiotherapy, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane (Australia)

    2008-06-15

    Aim: To investigate the presence of fatty infiltrate in the cervical extensor musculature in patients with insidious-onset neck pain to better understand the possible pathophysiology underlying such changes in chronic whiplash-associated disorders (WAD). Materials and methods: A sample of convenience of 23 women with persistent insidious-onset neck pain (mean age 29.2 {+-} 6.9 years) was recruited for the study. Magnetic resonance imaging (MRI) was used to quantify fatty infiltration in the cervical extensor musculature. Quantitative Sensory Testing (QST; pressure and thermal pain thresholds) was performed as sensory features are present in chronic whiplash. Self-reported pain and disability, as well as psychological distress, were measured using the Neck Disability Index (NDI) and the General Health Questionnaire-28 (GHQ-28), respectively. Results: Measures were compared with those of a previous dataset of chronic whiplash patients (n = 79, mean age 29.7 {+-} 7.8 years). Using a classification tree, insidious-onset neck pain was clearly identified from whiplash (p < 0.001), based on the presence of MRI fatty infiltrate in the cervical extensor musculature (0/102 individuals) and altered temperature thresholds (cold; 3/102 individuals). Conclusion: Fatty infiltrates in the cervical extensor musculature and widespread hyperalgesia were not features of the insidious-onset neck pain group in this study; whereas these features have been identified in patients with chronic WAD. This novel finding may enable a better understanding of the underlying pathophysiological processes in patients with chronic whiplash.

  15. Fatty infiltrate in the cervical extensor muscles is not a feature of chronic, insidious-onset neck pain

    International Nuclear Information System (INIS)

    Elliott, J.; Sterling, M.; Noteboom, J.T.; Darnell, R.; Galloway, G.; Jull, G.

    2008-01-01

    Aim: To investigate the presence of fatty infiltrate in the cervical extensor musculature in patients with insidious-onset neck pain to better understand the possible pathophysiology underlying such changes in chronic whiplash-associated disorders (WAD). Materials and methods: A sample of convenience of 23 women with persistent insidious-onset neck pain (mean age 29.2 ± 6.9 years) was recruited for the study. Magnetic resonance imaging (MRI) was used to quantify fatty infiltration in the cervical extensor musculature. Quantitative Sensory Testing (QST; pressure and thermal pain thresholds) was performed as sensory features are present in chronic whiplash. Self-reported pain and disability, as well as psychological distress, were measured using the Neck Disability Index (NDI) and the General Health Questionnaire-28 (GHQ-28), respectively. Results: Measures were compared with those of a previous dataset of chronic whiplash patients (n = 79, mean age 29.7 ± 7.8 years). Using a classification tree, insidious-onset neck pain was clearly identified from whiplash (p < 0.001), based on the presence of MRI fatty infiltrate in the cervical extensor musculature (0/102 individuals) and altered temperature thresholds (cold; 3/102 individuals). Conclusion: Fatty infiltrates in the cervical extensor musculature and widespread hyperalgesia were not features of the insidious-onset neck pain group in this study; whereas these features have been identified in patients with chronic WAD. This novel finding may enable a better understanding of the underlying pathophysiological processes in patients with chronic whiplash

  16. Sexual dimorphism of extensor carpi radialis muscle size, isometric force, relaxation rate and stamina during the breeding season of the frog Rana temporaria Linnaeus 1758.

    Science.gov (United States)

    Navas, Carlos A; James, Rob S

    2007-02-01

    Mating success of individual male frogs within explosive breeding species can depend on their ability to compete for a mate and to hold onto that mate during amplexus. Such importance of amplexus has resulted in the evolution of sexual dimorphism in the morphology and contractile characteristics of the anuran forelimb muscles used during amplexus. The aims of our study were to use an explosive breeding frog (Rana temporaria) during the breeding season to compare extensor carpi radialis (ECR) muscle length, mass, isometric activation times, relaxation times, absolute force, relative force (stress) and fatigue between male and female frogs. We found that ECR muscle mass and length were greater (tenfold and 1.4-fold, respectively), absolute tetanic muscle force and relative tetanic force (stress) were greater (16-fold and 2.2-fold, respectively) and relaxation times were slower in males than in females. Male ECR muscles incompletely relaxed during fatigue tests and showed less fatigue than female muscles. These sex differences are likely to be beneficial to the male frogs in allowing them to produce relatively high absolute muscle forces for prolonged periods of time to hold onto their mate during amplexus.

  17. Rupture of the medial gastrocnemius muscle during namaz praying: an unusual cause of tennis leg.

    Science.gov (United States)

    Yilmaz, Cengiz; Orgenc, Yaman; Ergenc, Ruken; Erkan, Nazif

    2008-12-01

    The aim of this retrospective study is to report a unique group of patients in whom rupture of the medial gastrocnemius muscle (tennis leg) occurred during namaz praying. We reviewed the sonographic and/or MR imaging findings of 543 patients who were referred for the evaluation of leg pain and swelling during the last 7 years. Fourteen patients with a final diagnosis of tennis leg that occured during namaz praying were included in this study. Nine of 14 (64.2%) patients had incomplete and the remainder 5 (35.8%) patients had a partial tear at the musculotendinous junction (MTJ). Four of 14 (28.6%) patients were mistaken for deep vein thrombosis (DVT) on the basis of clinical findings and presentation. Associated fluid collection between the gastrocnemius and soleus muscle was noted in 11 (78.5%) patients. Isolated fluid collection between the gastrocnemius and soleus muscle without disruption of the gastrocnemius muscle was seen in 1 patient. Rupture of the medial gastrocnemius muscle may occur during namaz praying. The clinical presentation is not always characteristic and may simulate DVT. US and MRI are useful diagnostic tools to establish the correct diagnosis and prompt further treatment.

  18. A combination of resistance and endurance training increases leg muscle strength in COPD

    DEFF Research Database (Denmark)

    Iepsen, Ulrik Winning; Jørgensen, Karsten Juhl; Ringbæk, Thomas

    2015-01-01

    Resistance training (RT) is thought to be effective in preventing muscle depletion, whereas endurance training (ET) is known to improve exercise capacity and health-related quality of life (HRQoL) in chronic obstructive pulmonary disease (COPD). Our objectives were to assess the efficiency...... improvements in HRQoL, walking distance and exercise capacity. However, we found moderate quality evidence of a significant increase in leg muscle strength favouring a combination of RT and ET (standardized mean difference of 0.69 (95% confidence interval: 0.39-0.98). In conclusion, we found significantly...... increased leg muscle strength favouring a combination of RT with ET compared with ET alone. Therefore, we recommend that RT should be incorporated in rehabilitation of COPD together with ET....

  19. Computed tomographic findings of leg muscles in the hemiplegics due to cerebrovascular accidents

    International Nuclear Information System (INIS)

    Odajima, Natsu; Ishiai, Sumio; Kotera, Minoru; Furukawa, Tetsuo; Tsukagoshi, Hiroshi.

    1986-01-01

    The computed tomography (CT) scan was performed in 52 hemiplegics due to cerebrovascular accidents and 12 normal controls on the mid-portion of the thigh and the largest-diameter section of the calf. Muscle size and average CT density of the muscle were measured. The salient feature was hypertrophic gracilis muscle of the hemiplegic side. Other muscles were more atrophied with lower CT density compared with those of the contralateral side. The size of the quadriceps muscle was especially small. The ratio of the quadriceps to all the thigh muscles in cross section was significantly smaller in affected side of hemiplegics than that of normal controls. This was observed even in normal side of the hemiplegics but the ratios of adductor and flexor muscles of the thigh showed no difference. Hypertrophy of gracilis muscle with high CT density was observed only on hemiplegic side. Muscle atrophies were marked in non-ambulatory patients. The ratios of quadriceps and saltorius muscles of thigh in non-ambulatory patients were significantly smaller than those of ambulatory patients. It could not be detected that there is relationship of the sevirity of the muscle atrophy and parietal lobe dysfunction. This atrophy considered to be the result of disuse of the paralyzed leg and pyramidal tract dysfunction. (author)

  20. Maintained peak leg and pulmonary VO2 despite substantial reduction in muscle mitochondrial capacity

    DEFF Research Database (Denmark)

    Boushel, Robert; Gnaiger, E.; Larsen, F. J.

    2015-01-01

    We recently reported the circulatory and muscle oxidative capacities of the arm after prolonged low-intensity skiing in the arctic (Boushel et al., 2014). In the present study, leg VO2 was measured by the Fick method during leg cycling while muscle mitochondrial capacity was examined on a biopsy ...... at a higher mitochondrial p50. These findings support the concept that muscle mitochondrial respiration is submaximal at VO2max , and that mitochondrial volume can be downregulated by chronic energy demand....

  1. Motor-neuron pool excitability of the lower leg muscles after acute lateral ankle sprain.

    Science.gov (United States)

    Klykken, Lindsey W; Pietrosimone, Brian G; Kim, Kyung-Min; Ingersoll, Christopher D; Hertel, Jay

    2011-01-01

    Neuromuscular deficits in leg muscles that are associated with arthrogenic muscle inhibition have been reported in people with chronic ankle instability, yet whether these neuromuscular alterations are present in individuals with acute sprains is unknown. To compare the effect of acute lateral ankle sprain on the motor-neuron pool excitability (MNPE) of injured leg muscles with that of uninjured contralateral leg muscles and the leg muscles of healthy controls. Case-control study. Laboratory. Ten individuals with acute ankle sprains (6 females, 4 males; age= 19.2 ± 3.8 years, height= 169.4 ± 8.5 cm, mass= 66.3 ± 11.6 kg) and 10 healthy individuals(6 females,4 males; age= 20.6 ± 4.0 years, height = 169.9 ± 10.6 cm, mass= 66.3 ± 10.2 kg) participated. The independent variables were group (acute ankle sprain, healthy) and limb (injured, uninjured). Separate dependent t tests were used to determine differences in MNPE between legs. The MNPE of the soleus, fibularis longus, and tibialis anterior was measured by the maximal Hoffmann reflex (H(max)) and maximal muscle response (M(max)) and was then normalized using the H(max):M(max) ratio. The soleus MNPE in the ankle-sprain group was higher in the injured limb (H(max):M(max) = 0.63; 95% confidence interval [Cl],0.46, 0.80) than the uninjured limb (H(max):M(max) = 0.47; 95%Cl, 0.08, 0.93)(t(6) = 3.62,P =.01).In the acute ankle-sprain group, tibialis anterior MNPE tended to be lower in the injured ankle (H(max):M(max) =0.06; 95% Cl, 0.01, 0.10) than in the uninjured ankle (H(max):M(max) =0.22; 95%Cl, 0.09, 0.35),but this finding was not different (t(9) =-2.01, P =.07). No differences were detected between injured (0.22; 95% Cl, 0.14, 0.29) and uninjured (0.25; 95%Cl, 0.12, 0.38) ankles for the fibularis longus in the ankle-sprain group (t(9) =-0.739, P =.48). We found no side-to-side differences in any muscle among the healthy group. Facilitated MNPE was present in the involved soleus muscle of patients with acute

  2. Control of leg movements driven by EMG activity of shoulder muscles

    Directory of Open Access Journals (Sweden)

    Valentina eLa Scaleia

    2014-10-01

    Full Text Available During human walking there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here we present a novel approach for associating the electromyographic (EMG activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural coordination between arms and legs. Nine healthy subjects were asked to walk at different constant and variable speeds (3-5 km/h, while EMG activity of shoulder (deltoid muscles and the kinematics of walking were recorded. To ensure a high level of EMG activity in deltoid, the subjects performed slightly larger arm swinging than they usually do. The temporal structure of the burst-like EMG activity was used to predict the spatiotemporal kinematic pattern of the forthcoming step. A comparison of actual and predicted stride leg kinematics showed a high degree of correspondence (r>0.9. This algorithm has been also implemented in pilot experiments for controlling avatar walking in a virtual reality setup and an exoskeleton during overground stepping. The proposed approach may have important implications for the design of human-machine interfaces and neuroprosthetic technologies such as those of assistive lower limb exoskeletons.

  3. 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.

  4. Magnetic resonance imaging analysis of the upper cervical spine extensor musculature in an asymptomatic cohort: an index of fat within muscle

    International Nuclear Information System (INIS)

    Elliott, J.M.; Galloway, G.J.; Jull, G.A.; Noteboom, J.T.; Centeno, C.J.; Gibbon, W.W.

    2005-01-01

    AIM: To establish a simple method to quantify muscle/fat constituents in cervical muscles of asymptomatic women using magnetic resonance imaging (MRI), and to determine whether there is an age effect within a defined age range. MATERIALS AND METHODS: MRI of the upper cervical spine was performed for 42 asymptomatic women aged 18-45 years. The muscle and fat signal intensities on axial spin echo T1-weighted images were quantitatively classified by taking a ratio of the pixel intensity profiles of muscle against those of intermuscular fat for the rectus capitis posterior major and minor and inferior obliquus capitis muscles bilaterally. Inter- and intra-examiner agreement was scrutinized. RESULTS: The average relative values of fat within the upper cervical musculature compared with intermuscular fat indicated that there were only slight variations in indices between the three sets of muscles. There was no significant correlation between age and fat indices. There were significant differences for the relative fat within the muscle compared with intermuscular fat and body mass index for the right rectus capitis posterior major and right and left inferior obliquus capitis muscles (p=0.032). Intraclass correlation coefficients for intraobserver agreement ranged from 0.94 to 0.98. Inter-rater agreement of the measurements ranged from 0.75 to 0.97. CONCLUSION: A quantitative measure of muscle/fat constituents has been developed, and results of this study indicate that relative fatty infiltration is not a feature of age in the upper cervical extensor muscles of women aged 18-45 years

  5. Magnetic resonance imaging analysis of the upper cervical spine extensor musculature in an asymptomatic cohort: an index of fat within muscle

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, J.M. [Division of Physiotherapy, University of Queensland, Brisbane, QLD (Australia)]. E-mail: jimelliott@plbb.net; Galloway, G.J. [Center for Magnetic Resonance, University of Queensland, Brisbane, QLD (Australia); Jull, G.A. [Division of Physiotherapy, University of Queensland, Brisbane, QLD (Australia); Noteboom, J.T. [Department of Physical Therapy, Regis University, Denver, CO, USA (United States); Centeno, C.J. [Centeno Clinic, Westminster, CO, USA (United States); Gibbon, W.W. [Department of Radiology, School of Medicine, University of Queensland, Brisbane, QLD (Australia)

    2005-03-01

    AIM: To establish a simple method to quantify muscle/fat constituents in cervical muscles of asymptomatic women using magnetic resonance imaging (MRI), and to determine whether there is an age effect within a defined age range. MATERIALS AND METHODS: MRI of the upper cervical spine was performed for 42 asymptomatic women aged 18-45 years. The muscle and fat signal intensities on axial spin echo T1-weighted images were quantitatively classified by taking a ratio of the pixel intensity profiles of muscle against those of intermuscular fat for the rectus capitis posterior major and minor and inferior obliquus capitis muscles bilaterally. Inter- and intra-examiner agreement was scrutinized. RESULTS: The average relative values of fat within the upper cervical musculature compared with intermuscular fat indicated that there were only slight variations in indices between the three sets of muscles. There was no significant correlation between age and fat indices. There were significant differences for the relative fat within the muscle compared with intermuscular fat and body mass index for the right rectus capitis posterior major and right and left inferior obliquus capitis muscles (p=0.032). Intraclass correlation coefficients for intraobserver agreement ranged from 0.94 to 0.98. Inter-rater agreement of the measurements ranged from 0.75 to 0.97. CONCLUSION: A quantitative measure of muscle/fat constituents has been developed, and results of this study indicate that relative fatty infiltration is not a feature of age in the upper cervical extensor muscles of women aged 18-45 years.

  6. Relationship between lower extremity isometric muscle strength and standing balance in patients with multiple sclerosis.

    Science.gov (United States)

    Citaker, Seyit; Guclu-Gunduz, Arzu; Yazici, Gokhan; Bayraktar, Deniz; Nazliel, Bijen; Irkec, Ceyla

    2013-01-01

    Muscle strength and standing balance decrease in patients with Multiple Sclerosis (MS). The aim of the present study was to investigate the relationship between the lower extremity isometric muscle strength and standing balance in patients with MS. Forty-seven patients with MS and 10 healthy volunteers were included. Neurological disability level was assessed using Expanded Disability Status Scale (EDSS). Isometric strength of seven lower extremity muscles (hip flexor-extensor-abductor-adductor, knee flexor-extensor, and ankle dorsal flexor) was assessed using hand-held dynamometer. Duration of static one-leg standing balance was measured using digital chronometer. Hip flexor-extensor-abductor-adductor, knee flexor-extensor, and ankle dorsal flexor isometric muscle strength, and duration of one-leg standing balance were decreased in patients with MS when compared with controls (p isometric muscle strength and EDSS level was related duration of one-leg standing balance in patients with MS. All assessed lower extremity isometric muscle strength (except ankle dorsal flexor) was related with EDSS. Hip flexor-extensor-abductor-adductor, knee flexor-extensor, and ankle dorsal flexor isometric muscle strength decreases in ambulatory MS patients. Lower extremity muscle weakness and neurological disability level are related with imbalance in MS population. Hip and knee region muscles weakness increases the neurological disability level. For the better balance and decrease neurological disability level whole lower extremity muscle strengthening should be included in rehabilitation programs.

  7. The effects of surface condition on abdominal muscle activity during single-legged hold exercise.

    Science.gov (United States)

    Ha, Sung-min; Oh, Jae-seop; Jeon, In-cheol; Kwon, Oh-yun

    2015-02-01

    To treat low-back pain, various spinal stability exercises are commonly used to improve trunk muscle function and strength. Because human movement for normal daily activity occurs in multi-dimensions, the importance of exercise in multi-dimensions or on unstable surfaces has been emphasized. Recently, a motorized rotating platform (MRP) for facilitating multi-dimensions dynamic movement was introduced for clinical use. However, the abdominal muscle activity with this device has not been reported. The purpose of this study was to compare the abdominal muscle activity (rectus abdominis, external and internal oblique muscles) during an active single-leg-hold (SLH) exercise on a floor (stable surface), foam roll, and motorized rotating platform (MRP). Thirteen healthy male subjects participated in this study. Using electromyography, the abdominal muscle activity was measured while the subjects performed SLH exercises on floor (stable surface), foam roll, and MRP. There were significant differences in the abdominal muscle activities among conditions (P.05) (Fig. 2). After the Bonferroni correction, however, no significant differences among conditions remained, except for differences in both side IO muscle activity between the floor and foam roll conditions (padjexercises on a foam roll and MRP is more effective increased activities of both side of RA and IO, and Rt. EO compared to floor condition. However, there were no significant differences in abdominal muscles activity in the multiple comparison between conditions (mean difference were smaller than the standard deviation in the abdominal muscle activities) (padj>0.017), except for differences in both side IO muscle activity between the floor (stable surface) and foam roll (padj<0.017) (effect size: 0.79/0.62 (non-supporting/supporting leg) for foam-roll versus floor). Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Experience with peroneus brevis muscle flaps for reconstruction of distal leg and ankle defects

    Directory of Open Access Journals (Sweden)

    Babu Bajantri

    2013-01-01

    Full Text Available Objective: Peroneus brevis is a muscle in the leg which is expendable without much functional deficit. The objective of this study was to find out its usefulness in coverage of the defects of the lower leg and ankle. Patients and Methods: A retrospective analysis of the use of 39 pedicled peroneus brevis muscle flaps used for coverage of defects of the lower leg and ankle between November 2010 and December 2012 was carried out. The flaps were proximally based for defects of the lower third of the leg in 12 patients and distally based for reconstruction of defects of the ankle in 26 patients, with one patient having flaps on both ankles. Results: Partial flap loss in critical areas was found in four patients requiring further flap cover and in non-critical areas in two patients, which were managed with a skin graft. Three of the four critical losses occurred when we used it for covering defects over the medial malleolus. There was no complete flap loss in any of the patients. Conclusion: This flap has a unique vascular pattern and fails to fit into the classification of the vasculature of muscles by Mathes and Nahai. The unusual feature is an axial vessel system running down the deep aspect of the muscle and linking the perforators from the peroneal artery and anterior tibial artery, which allows it to be raised proximally or distally on a single perforator. The flap is simple to raise and safe for the reconstruction of small-to moderate-sized skin defects of the distal third of the tibia and all parts of the ankle except the medial malleolus, which is too far from the pedicle of the distally based flap. The donor site can be closed primarily to provide a linear scar. The muscle flap thins with time to provide a good result aesthetically at the primary defect.

  9. [Electromyographic determination of the fatigability of respiratory and leg muscles before and after aortocoronary bypass operation].

    Science.gov (United States)

    Worth, H; Grundmann, C; Goeckenjan, G; Smidt, U; Irlich, G; Loogen, F

    1984-01-01

    To study the effect of postoperative confinement to bed on respiratory muscle fatigue, 31 male subjects (age, 34-66 years) undergoing coronary artery revascularization were examined. Fatigue of both respiratory muscles (musculi intercostales externi) and leg muscles (musculus gastrocnemius) was determined by electromyography prior to and 7 and 12 days after operation. Additionally, oscillatory resistance to breathing and phase angle were measured. Pre- and postoperative routine lung function tests were performed. A comparison between preoperative and postoperative measurements reveals that respiratory as well as leg muscle fatigue occurred at higher loads during the preoperative and the second postoperative than during the first postoperative determination. After surgery vital capacity, total lung capacity, 1-second capacity, and, to a lower extent, thoracic gas volume were diminished, while specific airway conductance, oscillatory resistance to breathing, phase angle, residual volume, and relative 1-second capacity remained unchanged. The constancy of the latter parameters indicates that neither airway obstruction nor a significant restriction of the lung and/or thorax occurred due to surgery. Therefore, the increase of respiratory muscle fatigue after surgery may more probably be attributed to a lack of training of respiratory muscles which may contribute to limitation of ventilation in bedridden patients.

  10. The influence of lower leg configurations on muscle force variability.

    Science.gov (United States)

    Ofori, Edward; Shim, Jaeho; Sosnoff, Jacob J

    2018-04-11

    The maintenance of steady contractions is required in many daily tasks. However, there is little understanding of how various lower limb configurations influence the ability to maintain force. The purpose of the current investigation was to examine the influence of joint angle on various lower-limb constant force contractions. Nineteen adults performed knee extension, knee flexion, and ankle plantarflexion isometric force contractions to 11 target forces, ranging from 2 to 95% maximal voluntary contraction (MVC) at 2 angles. Force variability was quantified with mean force, standard deviation, and the coefficient of variation of force output. Non-linearities in force output were quantified with approximate entropy. Curve fitting analyses were performed on each set of data from each individual across contractions to further examine whether joint angle interacts with global functions of lower-limb force variability. Joint angle had significant effects on the model parameters used to describe the force-variability function for each muscle contraction (p force output were more explained by force level in smaller angle conditions relative to the larger angle conditions (p force production. Biomechanical factors, such as joint angle, along with neurophysiological factors should be considered together in the discussion of the dynamics of constant force production. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Lower leg muscle involvement in Duchenne muscular dystrophy: an MR imaging and spectroscopy study

    International Nuclear Information System (INIS)

    Torriani, Martin; Townsend, Elise; Thomas, Bijoy J.; Bredella, Miriam A.; Ghomi, Reza H.; Tseng, Brian S.

    2012-01-01

    To describe the involvement of lower leg muscles in boys with Duchenne muscular dystrophy (DMD) by using MR imaging (MRI) and spectroscopy (MRS) correlated to indices of functional status. Nine boys with DMD (mean age, 11 years) and eight healthy age- and BMI-matched boys (mean age, 13 years) prospectively underwent lower leg MRI, 1H-MRS of tibialis anterior (TA) and soleus (SOL) for lipid fraction measures, and 31P-MRS for pH and high-energy phosphate measures. DMD subjects were evaluated using the Vignos lower extremity functional rating, and tests including 6 min walk test (6MWT) and 10 m walk. DMD subjects had highest fatty infiltration scores in peroneal muscles, followed by medial gastrocnemius and soleus. Compared to controls, DMD boys showed higher intramuscular fat (P = 0.04), lipid fractions of TA and SOL (P = 0.02 and 0.003, respectively), pH of anterior compartment (P = 0.0003), and lower phosphocreatine/inorganic phosphorus ratio of posterior compartment (P = 0.02). The Vignos rating correlated with TA (r = 0.79, P = 0.01) and SOL (r = 0.71, P = 0.03) lipid fractions. The 6MWT correlated with fatty infiltration scores of SOL (r = -0.76, P = 0.046), medial (r = -0.80, P = 0.03) and lateral (r = -0.84, P = 0.02) gastrocnemius, intramuscular fat (r = -0.80, P = 0.03), and SOL lipid fraction (r = -0.89, P = 0.007). Time to walk 10 m correlated with anterior compartment pH (r = 0.78, P = 0.04). Lower leg muscles of boys with DMD show a distinct involvement pattern and increased adiposity that correlates with functional status. Lower leg MRI and 1H-MRS studies may help to noninvasively demonstrate the severity of muscle involvement. (orig.)

  12. Lower leg muscle involvement in Duchenne muscular dystrophy: an MR imaging and spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Torriani, Martin [Massachusetts General Hospital and Harvard Medical School, Division of Musculoskeletal Imaging and Intervention, Boston, MA (United States); Massachusetts General Hospital, Musculoskeletal Imaging and Intervention, Department of Radiology, Boston, MA (United States); Townsend, Elise [MGH Institute of Health Professions and Massachusetts General Hospital, Boston, MA (United States); Thomas, Bijoy J.; Bredella, Miriam A.; Ghomi, Reza H. [Massachusetts General Hospital and Harvard Medical School, Division of Musculoskeletal Imaging and Intervention, Boston, MA (United States); Tseng, Brian S. [Massachusetts General Hospital and Harvard Medical School, Pediatric Neuromuscular Clinic, Boston, MA (United States); Novartis Institute of Biomedical Research, Cambridge, MA (United States)

    2012-04-15

    To describe the involvement of lower leg muscles in boys with Duchenne muscular dystrophy (DMD) by using MR imaging (MRI) and spectroscopy (MRS) correlated to indices of functional status. Nine boys with DMD (mean age, 11 years) and eight healthy age- and BMI-matched boys (mean age, 13 years) prospectively underwent lower leg MRI, 1H-MRS of tibialis anterior (TA) and soleus (SOL) for lipid fraction measures, and 31P-MRS for pH and high-energy phosphate measures. DMD subjects were evaluated using the Vignos lower extremity functional rating, and tests including 6 min walk test (6MWT) and 10 m walk. DMD subjects had highest fatty infiltration scores in peroneal muscles, followed by medial gastrocnemius and soleus. Compared to controls, DMD boys showed higher intramuscular fat (P = 0.04), lipid fractions of TA and SOL (P = 0.02 and 0.003, respectively), pH of anterior compartment (P = 0.0003), and lower phosphocreatine/inorganic phosphorus ratio of posterior compartment (P = 0.02). The Vignos rating correlated with TA (r = 0.79, P = 0.01) and SOL (r = 0.71, P = 0.03) lipid fractions. The 6MWT correlated with fatty infiltration scores of SOL (r = -0.76, P = 0.046), medial (r = -0.80, P = 0.03) and lateral (r = -0.84, P = 0.02) gastrocnemius, intramuscular fat (r = -0.80, P = 0.03), and SOL lipid fraction (r = -0.89, P = 0.007). Time to walk 10 m correlated with anterior compartment pH (r = 0.78, P = 0.04). Lower leg muscles of boys with DMD show a distinct involvement pattern and increased adiposity that correlates with functional status. Lower leg MRI and 1H-MRS studies may help to noninvasively demonstrate the severity of muscle involvement. (orig.)

  13. Acute effects of maximal isometric muscle action of the elbow extensors on contralateral dynamic task of the elbow flexors: a pilot study

    Directory of Open Access Journals (Sweden)

    Cauê V La Scala Teixeira

    2017-12-01

    Full Text Available ABSTRACT Aim the aim was to investigate the influence of a maximal isometric muscle action of the elbow extensors on the contralateral dynamic task of the elbow flexors. Methods Seventeen recreationally trained men (23.3 ± 4.9 yrs, BMI: 24.8 ± 2.2 Kg/m² underwent two randomized different testing sessions separated by one week. In the control session (CON all subjects performed a maximum number of repetitions test (RMs at 75%1RM using the right elbow flexors. The experimental session (EXP was similar to the CON; however, all subjects were instructed to perform RMs at 75%1RM by using the right elbow flexors and maintaining the maximal voluntary contraction of the left elbow extensors during the test. RMs, rating of perceived exertion (RPE, and training volume (TV were measured and compared between sessions. Results The EXP showed a significant 10.4% increase on the RMs (13.8 vs. 12.5, p < 0.001, d = 0.44 and 12.1% increase in TV (238.0 vs. 212.4 kg, p < 0.001, d = 0.43 than CON. No differences were observed for RPE between sessions. Conclusion The maximum voluntary contraction of the left elbow extensors increased the RMs of the contralateral elbow flexors, reflecting a higher TV, and no differences in the RPE. Our results suggest that the investigated method may be a viable and practical alternative to increase the acute strength performance of elbow flexors when using submaximal loads.

  14. CT findings of leg muscles in the hemiplegics due to cerebrovascular accidents. Correlation to disuse atrophy

    Energy Technology Data Exchange (ETDEWEB)

    Odajima, Natsu; Ishiai, Sumio; Okiyama, Ryouichi; Furukawa, Tetsuo; Tsukagoshi, Hiroshi

    1987-09-01

    Muscle wastings in hemiplegics due to cerebrovascular accidents were studied with CT scanning in the mid-portion of the thigh and largest-diameter section of the calf bilaterally. Muscle size and average CT density of muscle were measured. The 80 patients were classified into one of the following three stages of disability, i.e. stage 1, severely disabled (wheel-chair-bound but capable of self care (20 patients)); stage 2, moderately disabled (poorly ambulatory (41 patients)); and stage 3, mildly disabled (well ambulatory (19 patients)). Muscle cross-sectional area and CT density in both legs of non-ambulatory patients were smaller and lower than those of other groups. The atrophic change was marked in the affected side, but it was also noticeable in the non-affected side. Gracilis muscle was relatively well spared in all 3 stages. These CT findings of hemiplegics were similar to those of disuse atropy in patients with knee or hip joint lesions. Atrophy was seen first in the quadriceps in thigh and flexor muscle group in calf. These findings were similar to the systemic myogenic or neurogenic atrophies. Although gracilis and sartorius muscles were spared in these systemic deseases, only gracilis muscle was spared in hemiplegics and in patients with disuse atrophy. The ratios of the size of quadriceps, adductor group and sartorius muscle of thigh in affected side to that of non-affected side were smaller in more severely disabled group. Those of the other muscles showed no differences among each stages. In stage 3, there was significant negative correlation between the ratio of quadriceps muscle and periods from the attack. There was no relationship between the severity of the muscle atrophy and parietal lobe lesion. The atrophy is considered to be the result of disuse from immobilization.

  15. CT findings of leg muscles in the hemiplegics due to cerebrovascular accidents

    International Nuclear Information System (INIS)

    Odajima, Natsu; Ishiai, Sumio; Okiyama, Ryouichi; Furukawa, Tetsuo; Tsukagoshi, Hiroshi.

    1987-01-01

    Muscle wastings in hemiplegics due to cerebrovascular accidents were studied with CT scanning in the mid-portion of the thigh and largest-diameter section of the calf bilaterally. Muscle size and average CT density of muscle were measured. The 80 patients were classified into one of the following three stages of disability, i.e. stage 1, severely disabled (wheel-chair-bound but capable of self care [20 patients]); stage 2, moderately disabled (poorly ambulatory [41 patients]); and stage 3, mildly disabled (well ambulatory [19 patients]). Muscle cross-sectional area and CT density in both legs of non-ambulatory patients were smaller and lower than those of other groups. The atrophic change was marked in the affected side, but it was also noticeable in the non-affected side. Gracilis muscle was relatively well spared in all 3 stages. These CT findings of hemiplegics were similar to those of disuse atropy in patients with knee or hip joint lesions. Atrophy was seen first in the quadriceps in thigh and flexor muscle group in calf. These findings were similar to the systemic myogenic or neurogenic atrophies. Although gracilis and sartorius muscles were spared in these systemic deseases, only gracilis muscle was spared in hemiplegics and in patients with disuse atrophy. The ratios of the size of quadriceps, adductor group and sartorius muscle of thigh in affected side to that of non-affected side were smaller in more severely disabled group. Those of the other muscles showed no differences among each stages. In stage 3, there was significant negative correlation between the ratio of quadriceps muscle and periods from the attack. There was no relationship between the severity of the muscle atrophy and parietal lobe lesion. The atrophy is considered to be the result of disuse from immobilization. (author)

  16. Análise eletromiográfica e força do grupo muscular extensor do punho durante isquemia induzida Electromyographic analysis and strength of the wrist extensor muscle group during induced ischemia

    Directory of Open Access Journals (Sweden)

    CCA Bandeira

    2009-02-01

    Full Text Available OBJETIVO: Avaliar o efeito da isquemia induzida sobre os parâmetros do sinal eletromiográfico e a força do grupo muscular extensor do punho (GMEP em mulheres saudáveis. MÉTODOS: Participaram 13 voluntárias, destras, sedentárias, com idade de 23,38±2,32 anos e índice de massa corporal (IMC de 20,68±1,87kg/m². Para determinar a força do GMEP, foram realizadas 3 contrações isométricas voluntárias máximas (CIVM, utilizando-se uma célula de carga por 15 segundos, com intervalos de 2 minutos entre cada contração, sendo todo procedimento repetido por 3 dias não consecutivos. A isquemia foi realizada por 5 minutos, utilizando um esfigmomanômetro posicionado no braço dominante e inflado até a ausência do fluxo sanguíneo, confirmada pelo ultrassom Doppler. Para coleta do sinal eletromiográfico do GMEP, utilizou-se o equipamento EMG1000 (Lynx® com eletrodo de superfície diferencial (Lynx®. Foram coletadas 3 CIVM por 15 segundos, com intervalo de 30 segundos entre elas, nas situações de pré-isquemia; isquemia; pós-isquemia imediata (pós-1 e pós-isquemia tardia (pós-2 - após 10 minutos do início da isquemia. Para análise dos parâmetros do sinal eletromiográfico, root mean square (RMS, e frequência mediana do espectro de potência do sinal foi utilizado o software MATLAB 6.5.1. Para análise estatística, foram utilizados os testes de Friedman e ANOVA two-way. RESULTADOS: A isquemia promoveu redução significativa (pOBJECTIVE: To analyze the effect of induced ischemia on the parameters of electromyographic signals and the strength of the wrist extensor muscle group (WEMG in healthy women. METHODS: Thirteen right-handed sedentary subjects aged 23.38±2.32 years old, with body mass index (BMI of 20.68±1.87kg/m², took part. To determine WEMG strength, three maximal voluntary isometric contractions (MVIC were performed using a load cell for 15 seconds, with 2 minutes intervals between contractions. The entire

  17. Influence of unstable footwear on lower leg muscle activity, volume change and subjective discomfort during prolonged standing.

    Science.gov (United States)

    Karimi, Zanyar; Allahyari, Teimour; Azghani, Mahmood Reza; Khalkhali, Hamidreza

    2016-03-01

    The present study was an attempt to investigate the effect of unstable footwear on lower leg muscle activity, volume change and subjective discomfort during prolonged standing. Ten healthy subjects were recruited to stand for 2 h in three footwear conditions: barefoot, flat-bottomed shoe and unstable shoe. During standing, lower leg discomfort and EMG activity of medial gastrocnemius (MG) and tibialis anterior (TA) muscles were continuously monitored. Changes in lower leg volume over standing time also were measured. Lower leg discomfort rating reduced significantly while subjects standing on unstable shoe compared to the flat-bottomed shoe and barefoot condition. For lower leg volume, less changes also were observed with unstable shoe. The activity level and variation of right MG muscle was greater with unstable shoe compared to the other footwear conditions; however regarding the left MG muscle, significant difference was found between unstable shoe and flat-bottomed shoe only for activity level. Furthermore no significant differences were observed for the activity level and variation of TA muscles (right/left) among all footwear conditions. The findings suggested that prolonged standing with unstable footwear produces changes in lower leg muscles activity and leads to less volume changes. Perceived discomfort also was lower for this type of footwear and this might mean that unstable footwear can be used as ergonomic solution for employees whose work requires prolonged standing. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  18. Quantification of leg muscle perfusion using thallium-201 single photon emission computed tomography

    International Nuclear Information System (INIS)

    Oshima, M.; Akanabe, H.; Sakuma, S.; Yano, T.; Nishikimi, N.; Shionoya, S.

    1989-01-01

    The purpose of this study is to quantify leg muscle perfusion with 201 Tl single photon emission computed tomography (SPECT). Six normal controls and 21 patients with peripheral arterial disease underwent this examination. Thallium-201 leg SPECT of both stress and redistribution was performed using a dual-headed digital gamma camera. Each slice of transverse images was normalized with pixels and whole-body counts. In normal controls, the activity of posterior tibial muscle components was significantly higher than that of anterior tibial muscle components (p less than 0.001). In 14 components, where patients had insignificant lesions, profile curves were normal in 10 (71%). In 62 components, where patients had arteriographically significant lesions, stress profile curves were abnormal in 57 (92%) compared with normal controls. Approximately, in half (28/62) components which had significant lesions, profile curves showed redistribution after 3 hr compared with normal redistribution curves. In three patients who underwent successful bypass graftings, the activity of each muscle component returned to a normal range

  19. Decreased muscle oxygenation and increased arterial blood flow in the non-exercising limb during leg exercise.

    Science.gov (United States)

    Shiroishi, Kiyoshi; Kime, Ryotaro; Osada, Takuya; Murase, Norio; Shimomura, Kousuke; Katsumura, Toshihito

    2010-01-01

    We evaluated arterial blood flow, muscle tissue oxygenation and muscle metabolism in the non-exercising limb during leg cycling exercise. Ten healthy male volunteers performed a graded leg cycling exercise at 0, 40, 80, 120 and 160 watts (W) for 5 min each. Tissue oxygenation index (TOI) of the non-exercising left forearm muscle was measured using a near-infrared spatially resolved spectroscopy (NIR(SRS)), and non-exercising forearm blood flow ((NONEX)FBF) in the brachial artery was also evaluated by a Doppler ultrasound system. We also determined O(2) consumption of the non-exercising forearm muscle (NONEXV(O)(2mus)) by the rate of decrease in O(2)Hb during arterial occlusion at each work rate. TOI was significantly decreased at 160 W (p exercising muscle may be reduced, even though (NONEX)FBF increases at high work rates during leg cycling exercise.

  20. Myosin heavy-chain isoforms in the flight and leg muscles of hummingbirds and zebra finches.

    Science.gov (United States)

    Velten, Brandy P; Welch, Kenneth C

    2014-06-01

    Myosin heavy chain (MHC) isoform complement is intimately related to a muscle's contractile properties, yet relatively little is known about avian MHC isoforms or how they may vary with fiber type and/or the contractile properties of a muscle. The rapid shortening of muscles necessary to power flight at the high wingbeat frequencies of ruby-throated hummingbirds and zebra finches (25-60 Hz), along with the varied morphology and use of the hummingbird hindlimb, provides a unique opportunity to understand how contractile and morphological properties of avian muscle may be reflected in MHC expression. Isoforms of the hummingbird and zebra finch flight and hindlimb muscles were electrophoretically separated and compared with those of other avian species representing different contractile properties and fiber types. The flight muscles of the study species operate at drastically different contraction rates and are composed of different histochemically defined fiber types, yet each exhibited the same, single MHC isoform corresponding to the chicken adult fast isoform. Thus, despite quantitative differences in the contractile demands of flight muscles across species, this isoform appears necessary for meeting the performance demands of avian powered flight. Variation in flight muscle contractile performance across species may be due to differences in the structural composition of this conserved isoform and/or variation within other mechanically linked proteins. The leg muscles were more varied in their MHC isoform composition across both muscles and species. The disparity in hindlimb MHC expression between hummingbirds and the other species highlights previously observed differences in fiber type composition and thrust production during take-off. Copyright © 2014 the American Physiological Society.

  1. Neck Flexor and Extensor Muscle Endurance in Subclinical Neck Pain: Intrarater Reliability, Standard Error of Measurement, Minimal Detectable Change, and Comparison With Asymptomatic Participants in a University Student Population.

    Science.gov (United States)

    Lourenço, Ana S; Lameiras, Carina; Silva, Anabela G

    2016-01-01

    The aims of this study were to assess intrarater reliability and to calculate the standard error of measurement (SEM) and minimal detectable change (MDC) for deep neck flexor and neck extensor muscle endurance tests, and compare the results between individuals with and without subclinical neck pain. Participants were students of the University of Aveiro reporting subclinical neck pain and asymptomatic participants matched for sex and age to the neck pain group. Data on endurance capacity of the deep neck flexors and neck extensors were collected by a blinded assessor using the deep neck flexor endurance test and the extensor endurance test, respectively. Intraclass correlation coefficients (ICCs), SEM, and MDC were calculated for measurements taken within a session by the same assessor. Differences between groups for endurance capacity were investigated using a Mann-Whitney U test. The deep neck flexor endurance test (ICC = 0.71; SEM = 6.91 seconds; MDC = 19.15 seconds) and neck extensor endurance test (ICC = 0.73; SEM = 9.84 minutes; MDC = 2.34 minutes) are reliable. No significant differences were found between participants with and without neck pain for both tests of muscle endurance (P > .05). The endurance capacity of the deep neck flexors and neck extensors can be reliably measured in participants with subclinical neck pain. However, the wide SEM and MDC might limit the sensitivity of these tests. Copyright © 2016. Published by Elsevier Inc.

  2. Ischemia Increases the Twitch Latent Period in the Soleus and Extensor Carpi Radialis Longus Muscles from Adult Rats.

    Science.gov (United States)

    Morales, Camilo; Fierro, Leonardo

    2017-10-01

    Complete ischemia and reperfusion effects on twitch force (∫(F·t)), twitch latent period (TLP), maximal rate of rise of twitch tension (δF/δt) max , and twitch maximum relaxation rate (TMRR) were assessed. We divided 36 adult rats into four groups; two control groups (n = 9), a group undergoing 1 hour of ischemia followed by 1 hour of reperfusion (n = 9), and one group exposed to 2 hours of ischemia followed by 1 hour of reperfusion (n = 9). We have induced twitch contractions every 10 minutes in the soleus and the extensor carpi radialis longus (ECRL). Twitch contractions were recorded and then analyzed for ∫(F·t), TLP, (δF/δt) max , and TMRR. During 1 hour and 40 minutes of ischemia, TLP increased to 179 ± 24% (p values.

  3. EFFECT OF MODERATE ALTITUDE ON PERIPHERAL MUSCLE OXYGENATION DURING LEG RESISTANCE EXERCISE IN YOUNG MALES

    Directory of Open Access Journals (Sweden)

    Toshio Matsuoka

    2004-09-01

    Full Text Available Training at moderate altitude (~1800m is often used by athletes to stimulate muscle hypoxia. However, limited date is available on peripheral muscle oxidative metabolism at this altitude (1800AL. The purpose of this study was to determine whether acute exposure to 1800AL alters muscle oxygenation in the vastus lateralis muscle during resistance exercise. Twenty young active male subjects (aged 16 - 21 yr performed up to 50 repetitions of the parallel squat at 1800AL and near sea level (SL. They performed the exercise protocol within 3 h after arrival at 1800 AL. During the exercise, the changes in oxygenated hemoglobin (OxyHb in the vastus lateralis muscle, arterial oxygen saturation (SpO2, and heart rate were measured using near infrared continuous wave spectroscopy (NIRcws and pulse oximetry, respectively. Changes in OxyHb were expressed by Deff defined as the relative index of the maximum change ratio (% from the resting level. OxyHb in the vastus lateralis muscle decreased dramatically from the resting level immediately after the start of exercise at both altitudes. The Deff during exercise was significantly (p < 0.001 lower at 1800AL (60.4 ± 6.2 % than at near SL (74.4 ± 7.6 %. SpO2 during exercise was significantly (p < 0.001 lower at 1800AL (92.0 ± 1.7 % than at near SL (96.7 ± 1.2 %. Differences (SL - 1800AL in Deff during exercise correlated fairly strongly with differences in SpO2 during exercise (r = 0.660. These results suggested that acute exposure to moderate altitude caused a more dramatical decrease in peripheral muscle oxygenation during leg resistance exercise. It is salient to note, therefore , that peripheral muscle oxygenation status at moderate altitude could be evaluated using NIRcws and that moderate altitudes might be effectively used to apply hypoxic stress on peripheral muscles.

  4. Bilateral anterior tarsal tunnel syndrome variant secondary to extensor hallucis brevis muscle hypertrophy in a ballet dancer: a case report.

    Science.gov (United States)

    Tennant, Joshua N; Rungprai, Chamnanni; Phisitkul, Phinit

    2014-12-01

    We present a case of bilateral anterior tarsal tunnel syndrome secondary EHB hypertrophy in a dancer, with successful treatment with bilateral EHB muscle excisions for decompression. The bilateral presentation of this case with the treatment of EHB muscle excision is the first of its type reported in the literature. Copyright © 2014 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  5. Ankle muscle activity modulation during single-leg stance differs between children, young adults and seniors.

    Science.gov (United States)

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

    2018-02-01

    Incomplete maturation and aging-induced declines of the neuromuscular system affect postural control both in children and older adults and lead to high fall rates. Age-specific comparisons of the modulation of ankle muscle activation and behavioral center of pressure (COP) indices during upright stance have been rarely conducted. The objective of the present study was to quantify aging effects on a neuromuscular level. Thus, surface electromyography (SEMG) modulation and co-activity of ankle muscles during single-leg standing was compared in healthy children, young adults and seniors. Postural steadiness (velocity and mean sway frequency of COP), relative muscle activation (SEMG modulation) and co-activation of two ankle muscles (tibialis anterior, TA; soleus, SO) were examined during single-leg stance in 19 children [age, 9.7 (SD 0.5) years], 30 adults [23.3 (1.5) years] and 29 seniors [62.7 (6.1) years]. Velocity of COP in medio-lateral and anterior-posterior directions, mean sway frequency in anterior-posterior direction, relative muscle activation (TA and SO) and co-activation revealed large age effects (P  0.14). Post-hoc comparisons indicated higher COP velocities, anterior-posterior frequencies, relative SO activation and co-activation in children and seniors when compared with adults. Relative TA activation was higher in children and adults compared with seniors (P seniors seems to be counteracted with higher TA/SO co-activity and SO modulation. However, TA modulation is higher in children and adults, whereas seniors' TA modulation capacity is diminished. An aging-induced decline of TA motor units might account for deteriorations of TA modulation in seniors.

  6. Intermittent pneumatic leg compressions acutely upregulate VEGF and MCP-1 expression in skeletal muscle.

    Science.gov (United States)

    Roseguini, Bruno T; Mehmet Soylu, S; Whyte, Jeffrey J; Yang, H T; Newcomer, Sean; Laughlin, M Harold

    2010-06-01

    Application of intermittent pneumatic compressions (IPC) is an extensively used therapeutic strategy in vascular medicine, but the mechanisms by which this method works are unclear. We tested the hypothesis that acute application (150 min) of cyclic leg compressions in a rat model signals upregulation of angiogenic factors in skeletal muscle. To explore the impact of different pressures and frequency of compressions, we divided rats into four groups as follows: 120 mmHg (2 s inflation/2 s deflation), 200 mmHg (2 s/2 s), 120 mmHg (4 s/16 s), and control (no intervention). Blood flow and leg oxygenation (study 1) and the mRNA expression of angiogenic mediators in the rat tibialis anterior muscle (study 2) were assessed after a single session of IPC. In all three groups exposed to the intervention, a modest hyperemia (approximately 37% above baseline) between compressions and a slight, nonsignificant increase in leg oxygen consumption (approximately 30%) were observed during IPC. Compared with values in the control group, vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1) mRNA increased significantly (P < 0.05) only in rats exposed to the higher frequency of compressions (2 s on/2 s off). Endothelial nitric oxide synthase, matrix metalloproteinase-2, and hypoxia-inducible factor-1alpha mRNA did not change significantly following the intervention. These findings show that IPC application augments the mRNA content of key angiogenic factors in skeletal muscle. Importantly, the magnitude of changes in mRNA expression appeared to be modulated by the frequency of compressions such that a higher frequency (15 cycles/min) evoked more robust changes in VEGF and MCP-1 compared with a lower frequency (3 cycles/min).

  7. Prophylactic knee bracing alters lower-limb muscle forces during a double-leg drop landing.

    Science.gov (United States)

    Ewing, Katie A; Fernandez, Justin W; Begg, Rezaul K; Galea, Mary P; Lee, Peter V S

    2016-10-03

    Anterior cruciate ligament (ACL) injury can be a painful, debilitating and costly consequence of participating in sporting activities. Prophylactic knee bracing aims to reduce the number and severity of ACL injury, which commonly occurs during landing maneuvers and is more prevalent in female athletes, but a consensus on the effectiveness of prophylactic knee braces has not been established. The lower-limb muscles are believed to play an important role in stabilizing the knee joint. The purpose of this study was to investigate the changes in lower-limb muscle function with prophylactic knee bracing in male and female athletes during landing. Fifteen recreational athletes performed double-leg drop landing tasks from 0.30m and 0.60m with and without a prophylactic knee brace. Motion analysis data were used to create subject-specific musculoskeletal models in OpenSim. Static optimization was performed to calculate the lower-limb muscle forces. A linear mixed model determined that the hamstrings and vasti muscles produced significantly greater flexion and extension torques, respectively, and greater peak muscle forces with bracing. No differences in the timings of peak muscle forces were observed. These findings suggest that prophylactic knee bracing may help to provide stability to the knee joint by increasing the active stiffness of the hamstrings and vasti muscles later in the landing phase rather than by altering the timing of muscle forces. Further studies are necessary to quantify whether prophylactic knee bracing can reduce the load placed on the ACL during intense dynamic movements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Glucose uptake heterogeneity of the leg muscles is similar between patients with multiple sclerosis and healthy controls during walking.

    Science.gov (United States)

    Kindred, John H; Ketelhut, Nathaniel B; Rudroff, Thorsten

    2015-02-01

    Difficulties in ambulation are one of the main problems reported by patients with multiple sclerosis. A previous study by our research group showed increased recruitment of muscle groups during walking, but the influence of skeletal muscle properties, such as muscle fiber activity, has not been fully elucidated. The purpose of this investigation was to use the novel method of calculating glucose uptake heterogeneity in the leg muscles of patients with multiple sclerosis and compare these results to healthy controls. Eight patients with multiple sclerosis (4 men) and 8 healthy controls (4 men) performed 15 min of treadmill walking at a comfortable self-selected speed following muscle strength tests. Participants were injected with ≈ 8 mCi of [(18)F]-fluorodeoxyglucose during walking after which positron emission tomography/computed tomography imaging was performed. No differences in muscle strength were detected between multiple sclerosis and control groups (P>0.27). Within the multiple sclerosis, group differences in muscle volume existed between the stronger and weaker legs in the vastus lateralis, semitendinosus, and semimembranosus (Pmuscle group or individual muscle of the legs (P>0.16, P≥0.05). Patients with multiple sclerosis and healthy controls showed similar muscle fiber activity during walking. Interpretations of these results, with respect to our previous study, suggest that walking difficulties in patients with multiple sclerosis may be more associated with altered central nervous system motor patterns rather than alterations in skeletal muscle properties. Published by Elsevier Ltd.

  9. Metabolism of branched-chain amino acids in leg muscles from tail-cast suspended intact and adrenalectomized rats

    Science.gov (United States)

    Jaspers, Stephen R.; Henriksen, Erik; Jacob, Stephan; Tischler, Marc E.

    1989-01-01

    The effects of muscle unloading, adrenalectomy, and cortisol treatment on the metabolism of branched-chain amino acids in the soleus and extensor digitorum longus of tail-cast suspended rats were investigated using C-14-labeled lucine, isoleucine, and valine in incubation studies. It was found that, compared to not suspended controls, the degradation of branched-chain amino acids in hind limb muscles was accelerated in tail-cast suspended rats. Adrenalectomy was found to abolish the aminotransferase flux and to diminish the dehydrogenase flux in the soleus. The data also suggest that cortisol treatment increases the rate of metabolism of branched-chain amino acids at the dehydrogenase step.

  10. Distal muscle activity alterations during the stance phase of gait in restless leg syndrome (RLS) patients.

    Science.gov (United States)

    Dafkin, Chloe; Green, Andrew; Olivier, Benita; McKinon, Warrick; Kerr, Samantha

    2018-05-01

    To assess if there is a circadian variation in electromyographical (EMG) muscle activity during gait in restless legs syndrome (RLS) patients and healthy control participants. Gait assessment was done in 14 RLS patients and 13 healthy control participants in the evening (PM) and the morning (AM). Muscle activity was recorded bilaterally from the tibialis anterior (TA), lateral gastrocnemius (GL), rectus femoris (RF) and biceps femoris (BF) muscles. A circadian variation during the stance phase in only TA (PM > AM, p  Controls, p < 0.05) during early stance and decreased GL activity (RLS < Controls, p < 0.01) during terminal stance in comparison to control participants in the evening. No other significant differences were noted between RLS patients and control participants. Activation of GL during the swing phase was noted in 79% of RLS patients and in 23% of control participants in the morning compared to 71% and 38% in the evening, respectively. EMG muscle activity shows no circadian variation in RLS patients. Evening differences in gait muscle activation patterns between RLS patients and control participants are evident. These results extend our knowledge about alterations in spinal processing during gait in RLS. A possible explanation for these findings is central pattern generator sensitization caused by increased sensitivity in cutaneous afferents in RLS patients. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Passive stiffness of monoarticular lower leg muscles is influenced by knee joint angle.

    Science.gov (United States)

    Ateş, Filiz; Andrade, Ricardo J; Freitas, Sandro R; Hug, François; Lacourpaille, Lilian; Gross, Raphael; Yucesoy, Can A; Nordez, Antoine

    2018-03-01

    While several studies demonstrated the occurrence of intermuscular mechanical interactions, the physiological significance of these interactions remains a matter of debate. The purpose of this study was to quantify the localized changes in the shear modulus of the gastrocnemius lateralis (GL), monoarticular dorsi- and plantar-flexor muscles induced by a change in knee angle. Participants underwent slow passive ankle rotations at the following two knee positions: knee flexed at 90° and knee fully extended. Ultrasound shear wave elastography was used to assess the muscle shear modulus of the GL, soleus [both proximally (SOL-proximal) and distally (SOL distal)], peroneus longus (PERL), and tibialis anterior (TA). This was performed during two experimental sessions (experiment I: n = 11; experiment II: n = 10). The shear modulus of each muscle was compared between the two knee positions. The shear modulus was significantly higher when the knee was fully extended than when the knee was flexed (P passive muscle force, these results provide evidence of a non-negligible intermuscular mechanical interaction between the human lower leg muscles during passive ankle rotations. The role of these interactions in the production of coordinated movements requires further investigation.

  12. Postural adjustments associated with voluntary contraction of leg muscles in standing man.

    Science.gov (United States)

    Nardone, A; Schieppati, M

    1988-01-01

    The postural adjustments associated with a voluntary contraction of the postural muscles themselves have been studied in the legs of normal standing men. We focussed on the following questions. Do postural adjustments precede the focal movement as in the case of movements of the upper limb? Which muscle(s) are involved in the task of stabilizing posture? Can the same postural muscle be activated in postural stabilization and in voluntary movement at the same time, in spite of the opposite changes in activity possibly required by these conditions? Six subjects standing on a dynamometric platform were asked to rise onto the tips their toes by contracting their soleus muscles, or to rock on their heels by contracting their tibialis anterior muscles. The tasks were made in a reaction time (RT) situation or in a self-paced mode, standing either freely or holding onto a stable structure. Surface EMGs of leg and thigh muscles, and the foot-floor reaction forces were recorded. The following results were obtained in the RT mode, standing freely. 1. Rising onto toe tips: a striking silent period in soleus preceded its voluntary activation; during this silent period, a tibialis anterior burst could be observed in three subjects; these anticipatory activities induced a forward sway, as monitored by a change in the force exerted along the x axis of the platform. 2. Rocking on heels: an enhancement in tonic EMG of soleus was observed before tibialis anterior voluntary burst, at a mean latency from the go-signal similar to that of the silent period; this anticipatory activity induced a backward body sway. 3. Choice RT conditions showed that the above anticipatory patterns in muscle activity were pre-programmed, specific for the intended tasks, and closely associated with the focal movement. When both tasks were performed in a self-paced mode, all the above EMG and mechanical features were more pronounced and unfolded in time. If the subjects held onto the frame, the early

  13. The role of eccentric regime of leg muscle work in alpine skiing

    Directory of Open Access Journals (Sweden)

    Ropret Robert

    2017-01-01

    Full Text Available Alpine skiing is characterized by a great number of leg movements with muscle contractions in eccentric regime. The role of these movements is to absorb gravitation and inertial forces, manage skis more precisely and maintain balance. Recent studies have determined the volume, duration and intenisty of eccentric contractions as well as the basic characteristics of movement amplitudes and velocities. Based on the previous findings the experiments involving eccentric training using a bicycle ergometer confirmed a positive impact that this kind of training has on increasing maximum power, strength, endurance, coordination, injury prevention, metabolic work efficiency, more efficient work with longer muscle length and its role in miming skiers' movements. This paper is an review of the studies so far in the field of kinematics, skiing dynamics and the effect of eccentric training on the development of athletes' performances.

  14. Tennis in hot and cool conditions decreases the rapid muscle torque production capacity of the knee extensors but not of the plantar flexors

    Science.gov (United States)

    Girard, Olivier; Racinais, Sébastien; Périard, Julien D

    2014-01-01

    Objectives To assess the time course of changes in rapid muscle force/torque production capacity and neuromuscular activity of lower limb muscles in response to prolonged (∼2 h) match-play tennis under heat stress. Methods The rates of torque development (RTD) and electromyographic activity (EMG; ie, root mean square) rise were recorded from 0 to 30, –50, –100 and –200 ms during brief (3–5 s) explosive maximal isometric voluntary contractions (MVC) of the knee extensors (KE) and plantar flexors (PF), along with the peak RTD within the entirety of the torque-time curve. These values were recorded in 12 male tennis players before (prematch) and after (postmatch, 24 and 48 h) match-play in HOT (∼37°C) and COOL (∼22°C) conditions. Results The postmatch core temperature was greater in the HOT (∼39.4°C) vs COOL (∼38.7°C) condition (ptorque. Furthermore, the rate of KE EMG activity rise remained unchanged. Conversely, the PF contractile RTD and rate of EMG activity rise were unaffected by the exercise or environmental conditions. Conclusions In the KE, a reduction in maximal torque production capacity following prolonged match-play tennis appears to account for the decrease in the rate of torque development, independent of environmental conditions, while remaining unchanged in the PF. PMID:24668381

  15. Lower leg muscle density is independently associated with fall status in community-dwelling older adults.

    Science.gov (United States)

    Frank-Wilson, A W; Farthing, J P; Chilibeck, P D; Arnold, C M; Davison, K S; Olszynski, W P; Kontulainen, S A

    2016-07-01

    Muscle density is a risk factor for fractures in older adults; however, its association with falls is not well described. After adjusting for biologically relevant confounding factors, a unit decrease in muscle density was associated with a 17 % increase in odds of reporting a fall, independent of functional mobility. Falls are the leading cause of injury, disability, and fractures in older adults. Low muscle density (i.e., caused by muscle adiposity) and functional mobility have been identified as risk factors for incident disability and fractures in older adults; however, it is not known if these are also independently associated with falls. The purpose of this study was to explore the associations of muscle density and functional mobility with fall status. Cross-sectional observational study of 183 men and women aged 60-98 years. Descriptive data, including a 12-month fall recall, Timed Up and Go (TUG) test performance, lower leg muscle area, and density. Odds ratio (OR) of being a faller were calculated, adjusted for age, sex, body mass index, general health status, diabetes, and comorbidities. Every mg/cm(3) increase in muscle density (mean 70.2, SD 2.6 mg/cm(3)) independently reduced the odds of being a faller by 19 % (OR 0.81 [95 % CI 0.67 to 0.97]), and every 1 s longer TUG test time (mean 9.8, SD 2.6 s) independently increased the odds by 17 % (OR 1.17 [95 % CI 1.01 to 1.37]). When both muscle density and TUG test time were included in the same model, only age (OR 0.93 [95 % CI 0.87 to 0.99]) and muscle density (OR 0.83 [95 % CI 0.69 to 0.99]) were independently associated with fall status. Muscle density was associated with fall status, independent of functional mobility. Muscle density may compliment functional mobility tests as a biometric outcome for assessing fall risk in well-functioning older adults.

  16. The effects of anthropometry and leg muscle power on drive and transition phase of acceleration

    DEFF Research Database (Denmark)

    Nikolaidis, Pantelis T.; Ingebrigtsen, Jørgen; Jeffreys, Ian

    2016-01-01

    Background: The aim of this study was to examine the effect of anthropometry and leg muscle power on accelerative ability and its phases (drive and transition). METHODS: Thirty-six soccer players (age 12.4±1.2 years, body mass 49.9±8.9 kg and height 154.2±10.3 cm) were tested twice, in the beginn......Background: The aim of this study was to examine the effect of anthropometry and leg muscle power on accelerative ability and its phases (drive and transition). METHODS: Thirty-six soccer players (age 12.4±1.2 years, body mass 49.9±8.9 kg and height 154.2±10.3 cm) were tested twice......, in the beginning and in the end of competitive season, for anthropometric characteristics, countermovement jump and 20-meter acceleration (split 0-10 meters and 10-20 meters, indices of drive and transition, respectively). The soccer players were grouped according to seasonal changes in 20-meter acceleration (δacc...

  17. ACTN3 R577X polymorphism and explosive leg-muscle power in elite basketball players.

    Science.gov (United States)

    Garatachea, Nuria; Verde, Zoraida; Santos-Lozano, Alejandro; Yvert, Thomas; Rodriguez-Romo, Gabriel; Sarasa, Francisco J; Hernández-Sánchez, Sonsoles; Santiago, Catalina; Lucia, Alejandro

    2014-03-01

    To determine the association of the ACTN3 R577X polymorphism with leg-muscle explosive power in Spanish (white) elite basketball players and controls. 100 (60 men) elite basketball players (cases) and 283 nonathletic controls. The authors assessed power performance by means of the vertical-squat and countermovement-jump tests. Genotype distributions did not differ between groups (cases: 37.0% [RR], 42.0% [RX], and 21.0% [XX]; controls: 31.8% [RR], 49.8% [RX], and 18.4% [XX]; P = .353). The authors did not observe any effect of the ACTN3 R577X polymorphism on study phenotypes in either group, including when they performed the analyses separately in men and women. They found no association between the ACTN3 R577X polymorphism and the likelihood of being an elite basketball player using the dominant or the recessive model, and the results remained unaltered when the analyses were adjusted for sex, weight, height, and age or when performed for men and women separately. Although the ACTN3 R577X is associated with explosive muscle performance and this phenotype is important in the sport of basketball (ie, during jumps), the authors found no association with leg explosive power in elite basket players or with the status of being this type of athlete.

  18. BUILDING A BETTER GLUTEAL BRIDGE: ELECTROMYOGRAPHIC ANALYSIS OF HIP MUSCLE ACTIVITY DURING MODIFIED SINGLE-LEG BRIDGES.

    Science.gov (United States)

    Lehecka, B J; Edwards, Michael; Haverkamp, Ryan; Martin, Lani; Porter, Kambry; Thach, Kailey; Sack, Richard J; Hakansson, Nils A

    2017-08-01

    Gluteal strength plays a role in injury prevention, normal gait patterns, eliminating pain, and enhancing athletic performance. Research shows high gluteal muscle activity during a single-leg bridge compared to other gluteal strengthening exercises; however, prior studies have primarily measured muscle activity with the active lower extremity starting in 90 ° of knee flexion with an extended contralateral knee. This standard position has caused reports of hamstring cramping, which may impede optimal gluteal strengthening. The purpose of this study was to determine which modified position for the single-leg bridge is best for preferentially activating the gluteus maximus and medius. Cross-Sectional. Twenty-eight healthy males and females aged 18-30 years were tested in five different, randomized single-leg bridge positions. Electromyography (EMG) electrodes were placed on subjects' gluteus maximus, gluteus medius, rectus femoris, and biceps femoris of their bridge leg (i.e., dominant or kicking leg), as well as the rectus femoris of their contralateral leg. Subjects performed a maximal voluntary isometric contraction (MVIC) for each tested muscle prior to performing five different bridge positions in randomized order. All bridge EMG data were normalized to the corresponding muscle MVIC data. A modified bridge position with the knee of the bridge leg flexed to 135 ° versus the traditional 90 ° of knee flexion demonstrated preferential activation of the gluteus maximus and gluteus medius compared to the traditional single-leg bridge. Hamstring activation significantly decreased (p bridge by flexing the active knee to 135 ° instead of 90 ° minimizes hamstring activity while maintaining high levels of gluteal activation, effectively building a bridge better suited for preferential gluteal activation. 3.

  19. The Effects of Active Straight Leg Raising on Tonicity and Activity of Pelvic Stabilizer Muscles

    Directory of Open Access Journals (Sweden)

    Azadeh Shadmehr

    2011-01-01

    Full Text Available Objective: Active straight leg raising (SLR test is advocated as a valid diagnostic method in diagnosis of sacroiliac joint (SIJ dysfunction that can assess the quality of load transfer between trunk and lower limb. The aim of this study is Comparison of changes in tonicity and activity of pelvic stabilizer muscles during active SLR, between healthy individuals and patients with sacroiliac joint pain. Materials & Methods: A case – control study was designed in 26 women (19-50 years old. With use of simple sampling, surface electromyography from rectus abdominis, external oblique, internal oblique, adductor longus, erector spine, gluteus maximus and biceps femoris was recorded in 26 subjects (15 healthy females and 11 females with sacroiliac pain in resting position and during active SLR test. Resting muscle tonicity and rms during ramp time and hold time in active SLR test were assessed by non parametric-two independent sample test. Results: Biceps femoris activity in resting position was significantly larger in patients group (P<0.05. During the active SLR, the women with sacroiliac joint pain used much less activity in some pelvic stabilizer muscles compared to the healthy subjects (P<0.05. Conclusion: The increased resting tonicity of biceps femoris and decreased activity of pelvic stabilizer muscles in subjects with sacroiliac joint pain, suggests an alteration in the strategy for lumbopelvic stabilization that may disrupt load transference through the pelvis.

  20. Structural Response of Lower Leg Muscles in Compression: A Low Impact Energy Study Employing Volunteers, Cadavers and the Hybrid III.

    Science.gov (United States)

    Dhaliwal, Trilok S; Beillas, Philippe; Chou, Clifford C; Prasad, Priya; Yang, King H; King, Albert I

    2002-11-01

    Little has been reported in the literature on the compressive properties of muscle. These data are needed for the development of finite element models that address impact of the muscles, especially in the study of pedestrian impact. Tests were conducted to characterize the compressive response of muscle. Volunteers, cadaveric specimens and a Hybrid III dummy were impacted in the posterior and lateral aspect of the lower leg using a free flying pendulum. Volunteer muscles were tested while tensed and relaxed. The effects of muscle tension were found to influence results, especially in posterior leg impacts. Cadaveric response was found to be similar to that of the relaxed volunteer. The resulting data can be used to identify a material law using an inverse method.

  1. Muscle stiffness of posterior lower leg in runners with a history of medial tibial stress syndrome.

    Science.gov (United States)

    Saeki, J; Nakamura, M; Nakao, S; Fujita, K; Yanase, K; Ichihashi, N

    2018-01-01

    Previous history of medial tibial stress syndrome (MTSS) is a risk factor for MTSS relapse, which suggests that there might be some physical factors that are related to MTSS development in runners with a history of MTSS. The relationship between MTSS and muscle stiffness can be assessed in a cross-sectional study that measures muscle stiffness in subjects with a history of MTSS, who do not have pain at the time of measurement, and in those without a history of MTSS. The purpose of this study was to compare the shear elastic modulus, which is an index of muscle stiffness, of all posterior lower leg muscles of subjects with a history of MTSS and those with no history and investigate which muscles could be related to MTSS. Twenty-four male collegiate runners (age, 20.0±1.7 years; height, 172.7±4.8 cm; weight, 57.3±3.7 kg) participated in this study; 14 had a history of MTSS, and 10 did not. The shear elastic moduli of the lateral gastrocnemius, medial gastrocnemius, soleus, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and tibialis posterior were measured using shear wave elastography. The shear elastic moduli of the flexor digitorum longus and tibialis posterior were significantly higher in subjects with a history of MTSS than in those with no history. However, there was no significant difference in the shear elastic moduli of other muscles. The results of this study suggest that flexor digitorum longus and tibialis posterior stiffness could be related to MTSS. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Effects of β₂-agonists on force during and following anoxia in rat extensor digitorum longus muscle

    DEFF Research Database (Denmark)

    Fredsted, A; Gissel, H; Ortenblad, N

    2012-01-01

    of salbutamol on force recovery were prevented by blocking the Na(+),K(+)- pumps with ouabain or by blocking glycolysis with 2-deoxyglucose. Dibutyryl cAMP (1 mM) or theophylline (1 mM) also improved force recovery remarkably. In anoxic muscles, salbutamol decreased intracellular Na(+), increased (86)Rb uptake...

  3. Intermittent pneumatic compression of legs increases microcirculation in distant skeletal muscle.

    Science.gov (United States)

    Liu, K; Chen, L E; Seaber, A V; Johnson, G W; Urbaniak, J R

    1999-01-01

    Intermittent pneumatic compression has been established as a method of clinically preventing deep vein thrombosis, but the mechanism has not been documented. This study observed the effects of intermittent pneumatic compression of legs on the microcirculation of distant skeletal muscle. The cremaster muscles of 80 male rats were exposed, a specially designed intermittent pneumatic-compression device was applied to both legs for 60 minutes, and the microcirculation of the muscles was assessed by measurement of the vessel diameter in three categories (10-20, 21-40, and 41-70 microm) for 120 minutes. The results showed significant vasodilation in arterial and venous vessels during the application of intermittent pneumatic compression, which disappeared after termination of the compression. The vasodilation reached a maximum 30 minutes after initiation of the compression and could be completely blocked by an inhibitor of nitric oxide synthase, NG-monomethyl-L-arginine (10 micromol/min). A 120-minute infusion of NG-monomethyl-L-arginine, beginning coincident with 60 minutes of intermittent pneumatic compression, resulted in a significant decrease in arterial diameter that remained at almost the same level after termination of the compression. The magnitude of the decrease in diameter in the group treated with intermittent pneumatic compression and NG-monomethyl-L-arginine was comparable with that in the group treated with NG-monomethyl-L-arginine alone. The results imply that the production of nitric oxide is involved in the positive influence of intermittent pneumatic compression on circulation. It is postulated that the rapid increase in venous velocity induced by intermittent pneumatic compression produces strong shear stress on the vascular endothelium, which stimulates an increased release of nitric oxide and thereby causes systemic vasodilation.

  4. Using leg muscles as shock absorbers: theoretical predictions and experimental results of drop landing performance.

    Science.gov (United States)

    Minetti, A E; Ardigò, L P; Susta, D; Cotelli, F

    1998-12-01

    The use of muscles as power dissipators is investigated in this study, both from the modellistic and the experimental points of view. Theoretical predictions of the drop landing manoeuvre for a range of initial conditions have been obtained by accounting for the mechanical characteristics of knee extensor muscles, the limb geometry and assuming maximum neural activation. Resulting dynamics have been represented in the phase plane (vertical displacement versus speed) to better classify the damping performance. Predictions of safe landing in sedentary subjects were associated to dropping from a maximum (feet) height of 1.6-2.0 m (about 11 m on the moon). Athletes can extend up to 2.6-3.0 m, while for obese males (m = 100 kg, standard stature) the limit should reduce to 0.9-1.3 m. These results have been calculated by including in the model the estimated stiffness of the 'global elastic elements' acting below the squat position. Experimental landings from a height of 0.4, 0.7, 1.1 m (sedentary males (SM) and male (AM) and female (AF) athletes from the alpine ski national team) showed dynamics similar to the model predictions. While the peak power (for a drop height of about 0.7 m) was similar in SM and AF (AM shows a +40% increase, about 33 W/kg), AF stopped the downward movement after a time interval (0.219 +/- 0.030 s) from touch-down 20% significantly shorter than SM. Landing strategy and the effect of anatomical constraints are discussed in the paper.

  5. Histological Characteristics of Leg Muscles of 56-Day Old Pheasants Hatched from Eggs of Different Eggshell Colour

    Directory of Open Access Journals (Sweden)

    Dragan Zikic

    2015-05-01

    Full Text Available The aim of this paper was to examine the histological characteristics of leg muscles of pheasants hatched from eggs of a different colour. From muscle samples (M. biceps femoris of 56-day old pheasants hatched from eggs of different colour (dark brown, light brown, brown/green, blue/green histological preparations were made. Following parameters were examined: diameter of muscle cells, volume density of connective tissue in muscles, nucleo-cytoplasmatic ratio of muscle cells. Results showed that diameter of muscle cells was smaller in pheasants hatched from blue/green eggs compared to all other examinated groups. There was no differences in volume density of connective tissue in muscles between groups. Nucleo-cytoplasmatic ratio of muscle cells was higher in pheasants hatched from blue/green eggs compared to all other examinated groups. From obtained results it can be concluded that pheasants hatched from blue/green eggs had weaker muscle development than pheasants hatched from eggs of other eggshell colour. Cause of this could be related to structural differences of eggshells of various colour. This leads to weaker development of embryos and chicks hatched from blue/green eggs which reflects on differences in development of leg muscles.

  6. Postmortem changes in physiochemical and sensory properties of red snow crab (Chionoecetes japonicus leg muscle during freeze storage

    Directory of Open Access Journals (Sweden)

    Joon-Young Jun

    2017-07-01

    Full Text Available Abstract In order to evaluate the maximal storable period of the raw crab for a non-thermal muscle separation, the quality changes of the leg meat of red snow crab (Chionoecetes japonicus during freeze storage were investigated. Fresh red snow crabs were stored at −20 °C for 7 weeks, and the leg muscle was separated by a no heating separation (NHS method every week. During the storage, considerable loss of the leg muscle did not occur and microbiological risk was very low. In contrast, discoloration appeared at 2-week storage on around carapace and the leg muscle turned yellow at storage 3-week. In physiochemical parameters, protein and free amino acids gradually decreased with storage time, expected that proteolytic enzymes still activated at −20 °C. At 4-week storage, the sensory acceptance dropped down below point 4 as low as inedible and notable inflection points in pH and acidity were observed. The volatile base nitrogen was low, though a little increase was recorded. These results suggested that the maximal storable period at −20 °C of the raw material was within 2 weeks and it was depended on external factor such as the discoloration. The present study might be referred as basic data for approaches to solve quality loss occurred in non-thermal muscle separation.

  7. Preliminary observations on high energy phosphates and metabolic pathway and transporter potentials in extensor carpi radialis brevis and trapezius muscles of women with work-related myalgia.

    Science.gov (United States)

    Green, Howard J; Ranney, Don; Burnett, Margaret; Galvin, Patti; Kyle, Natasha; Lounsbury, David; Ouyang, Jing; Smith, Ian C; Stewart, Riley; Tick, Heather; Tupling, A Russell

    2014-11-01

    This study compared both the extensor carpi radialis brevis (ECRB) and the trapezius (TRAP) muscles of women with work-related myalgia (WRM) with healthy controls (CON) to determine whether abnormalities existed in cellular energy status and the potentials of the various metabolic pathways and segments involved in energy production and substrate transport. For both the ECRB (CON, n = 6-9; WRM, n = 13) and the TRAP (CON, n = 6-7; WRM, n = 10), no differences (P > 0.05) were found for the concentrations (in millimoles per kilogram of dry mass) of ATP, PCr, lactate, and glycogen. Similarly, with one exception, the maximal activities (in moles per milligram of protein per hour) of mitochondrial enzymes representative of the citric acid cycle (CAC), the electron transport chain (ETC), and β-oxidation, as well as the cytosolic enzymes involved in high energy phosphate transfer, glycogenolysis, glycolysis, lactate oxidation, and glucose phosphorylation were not different (P > 0.05). The glucose transporters GLUT1 and GLUT4, and the monocarboxylate transporters MCT1 and MCT4, were also normal in WRM. It is concluded that, in general, abnormalities in the resting energy and substrate state, the potential of the different metabolic pathways and segments, as well as the glucose and monocarboxylate transporters do not appear to be involved in the cellular pathophysiology of WRM.

  8. Test-retest reliability of maximal leg muscle power and functional performance measures in patients with severe osteoarthritis (OA)

    DEFF Research Database (Denmark)

    Villadsen, Allan; Roos, Ewa M.; Overgaard, Søren

    Abstract : Purpose To evaluate the reliability of single-joint and multi-joint maximal leg muscle power and functional performance measures in patients with severe OA. Background Muscle power, taking both strength and velocity into account, is a more functional measure of lower extremity muscle...... and scheduled for unilateral total hip (n=9) or knee (n=11) replacement. Patients underwent a test battery on two occasions separated by approximately one week (range 7 to 11 days). Muscle power was measured using: 1. A linear encoder, unilateral lower limb isolated single-joint dynamic movement, e.g. knee...... flexion 2. A leg extension press, unilateral multi-joint knee and hip extension Functional performance was measured using: 1. 20 m walk usual pace 2. 20 m walk maximal pace 3. 5 times chair stands 4. Maximal number of knee bends/30sec Pain was measured on a VAS prior to and after conducting the entire...

  9. A neuro-mechanical model of a single leg joint highlighting the basic physiological role of fast and slow muscle fibres of an insect muscle system.

    Directory of Open Access Journals (Sweden)

    Tibor Istvan Toth

    Full Text Available In legged animals, the muscle system has a dual function: to produce forces and torques necessary to move the limbs in a systematic way, and to maintain the body in a static position. These two functions are performed by the contribution of specialized motor units, i.e. motoneurons driving sets of specialized muscle fibres. With reference to their overall contraction and metabolic properties they are called fast and slow muscle fibres and can be found ubiquitously in skeletal muscles. Both fibre types are active during stepping, but only the slow ones maintain the posture of the body. From these findings, the general hypothesis on a functional segregation between both fibre types and their neuronal control has arisen. Earlier muscle models did not fully take this aspect into account. They either focused on certain aspects of muscular function or were developed to describe specific behaviours only. By contrast, our neuro-mechanical model is more general as it allows functionally to differentiate between static and dynamic aspects of movement control. It does so by including both muscle fibre types and separate motoneuron drives. Our model helps to gain a deeper insight into how the nervous system might combine neuronal control of locomotion and posture. It predicts that (1 positioning the leg at a specific retraction angle in steady state is most likely due to the extent of recruitment of slow muscle fibres and not to the force developed in the individual fibres of the antagonistic muscles; (2 the fast muscle fibres of antagonistic muscles contract alternately during stepping, while co-contraction of the slow muscle fibres takes place during steady state; (3 there are several possible ways of transition between movement and steady state of the leg achieved by varying the time course of recruitment of the fibres in the participating muscles.

  10. Tracking control of a leg rehabilitation machine driven by pneumatic artificial muscles using composite fuzzy theory.

    Science.gov (United States)

    Chang, Ming-Kun

    2014-01-01

    It is difficult to achieve excellent tracking performance for a two-joint leg rehabilitation machine driven by pneumatic artificial muscles (PAMs) because the system has a coupling effect, highly nonlinear and time-varying behavior associated with gas compression, and the nonlinear elasticity of bladder containers. This paper therefore proposes a T-S fuzzy theory with supervisory control in order to overcome the above problems. The T-S fuzzy theory decomposes the model of a nonlinear system into a set of linear subsystems. In this manner, the controller in the T-S fuzzy model is able to use simple linear control techniques to provide a systematic framework for the design of a state feedback controller. Then the LMI Toolbox of MATLAB can be employed to solve linear matrix inequalities (LMIs) in order to determine controller gains based on the Lyapunov direct method. Moreover, the supervisory control can overcome the coupling effect for a leg rehabilitation machine. Experimental results show that the proposed controller can achieve excellent tracking performance, and guarantee robustness to system parameter uncertainties.

  11. Muscle oxygen kinetics at onset of intense dynamic exercise in humans

    DEFF Research Database (Denmark)

    Bangsbo, J; Krustrup, P; González-Alonso, J

    2000-01-01

    The present study examined the onset and the rate of rise of muscle oxidation during intense exercise in humans and whether oxygen availability limits muscle oxygen uptake in the initial phase of intense exercise. Six subjects performed 3 min of intense one-legged knee-extensor exercise [65.3 +/-...

  12. Pneumatic Artificial Muscles Force Modelling and the Position and Stiffness Control on the Knee Joint of the Musculoskeletal Leg

    Directory of Open Access Journals (Sweden)

    Jingtao Lei

    2017-03-01

    Full Text Available Pneumatic artificial muscles (PAMs have properties similar to biological muscle and are widely used in robotics as actuators. A musculoskeletal leg mechanism driven by PAMs is presented in this paper. The joint stiffness of the musculoskeletal bionic leg for jumping movement needs to be analysed. The synchronous control on the position and stiffness of the joint is important to improve the flexibility of leg. The accurate force model of PAM is the foundation to achieving better control and dynamic jumping performance. The experimental platform of PAM is conducted, and the static equal pressure experiments are performed to obtain the PAM force model. According to the testing data, parameter identification method is adopted to determine the force model of PAM. A simulation on the position and stiffness control of the knee joint is performed, and the simulation results show the effectiveness of the presented method.

  13. Leg pain

    Science.gov (United States)

    ... in the blood Medicines (such as diuretics and statins) Muscle fatigue or strain from overuse, too much exercise, or holding a muscle in the same position for a long time An injury can also cause leg pain from: A torn or overstretched muscle ( strain ) Hairline ...

  14. Female PFP patients present alterations in eccentric muscle activity but not the temporal order of activation of the vastus lateralis muscle during the single leg triple hop test.

    Science.gov (United States)

    Kalytczak, Marcelo Martins; Lucareli, Paulo Roberto Garcia; Dos Reis, Amir Curcio; Bley, André Serra; Biasotto-Gonzalez, Daniela Aparecida; Correa, João Carlos Ferrari; Politti, Fabiano

    2018-04-07

    This study aimed to compare the concentric and eccentric activity and the temporal order of peak activity of the hip and knee muscles between women with patellofemoral pain (PFP) and healthy women during the single leg triple hop test (SLTHT). Electromyographic (EMG) and Kinematic data were collected from 14 healthy women (CG) and 14 women diagnosed with PFP (PFG) during a single session of the single leg triple hop test. Integral surface electromyography (iEMG) data of the hip and knee muscles in eccentric and concentric phases and the length of time that each muscle needed to reach the maximal peak of muscle activity were calculated. The iEMG in the eccentric phase was significantly higher (p < 0.05) than the concentric phase, for the gluteus maximus and gluteus medius muscles (CG and PFG) and for the vastus lateralis muscle (PFG). The vastus lateralis muscle was the first muscle to reach the highest peak of activity in the PFG, and the third to reach this peak in the CG. In the present study, the activity of the vastus lateralis muscle during the eccentric phase of the jump was greater than concentric phase, as a temporal anticipation of its peak in activity among women with PFP. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Quantification of muscle oxygenation and flow of healthy volunteers during cuff occlusion of arm and leg flexor muscles and plantar flexion exercise

    Science.gov (United States)

    Durduran, Turgut; Yu, Guoqiang; Zhou, Chao; Lech, Gwen; Chance, Britton; Yodh, Arjun G.

    2003-07-01

    A hybrid instrument combining near infrared and diffuse correlation spectroscopies was used to measure muscle oxygenation and blood flow dynamics during cuff occlusion and ischemia. Measurements were done on six healthy subjects on their arm and leg flexor muscles. Hemodynamic response was characterized for blood oxygen saturation, total hemoglobin concenration and relative blood flow speed. The characterization allowed us to define the normal response range as well as showing the feasibility of using a hybrid instrument for dynamic measurements.

  16. The effects of a muscle resistance program on the functional capacity, knee extensor muscle strength and plasma levels of IL-6 and TNF-alpha in pre-frail elderly women: a randomized crossover clinical trial--a study protocol.

    Science.gov (United States)

    Lustosa, Lygia P; Coelho, Fernanda M; Silva, Juscelio P; Pereira, Daniele S; Parentoni, Adriana N; Dias, João M D; Dias, Rosangela C; Pereira, Leani S M

    2010-07-28

    With the increase in the elderly population, a growing number of chronic degenerative diseases and a greater dependency on caregivers have been observed. Elderly persons in states of frailty remain more susceptible to significant health complications. There is evidence of an inverse relationship between plasma levels of inflammatory mediators and levels of functionality and muscle strength, suggesting that muscle-strengthening measures can aid in inflammatory conditions. The purpose of this study will be verified the effect of a muscle-strengthening program with load during a ten-week period in pre-frail elderly women with attention to the following outcomes: (1) plasma levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha), (2) functional capacity and (3) knee extensor muscle strength. The study design is a randomized crossover clinical trial evaluating 26 elderly women (regardless of their race and/or social condition) who are community residents, older than 65, and classified as pre-frail according to the criteria previously described by Fried et al. (2004). All subjects will be assessed using the Timed up and go and 10-Meter Walk Test functional tests. The plasma levels of IL-6 and TNF-alpha will be assessed by ELISA (enzyme-linked immunosorbent assay) with high sensitivity kits (QuantikineHS, R&D Systems Minneapolis, MN, U.S.). Knee extensor muscle strength will be assessed using the Byodex System 3 Pro(R) isokinetic dynamometer at angular speeds of 60 and 180 degrees/s. The intervention will consist of strengthening exercises of the lower extremities at 50 to 70% of 1RM (maximal resistance) three times per week for ten weeks. The volunteers will be randomized into two groups: group E, the intervention group, and group C, the control group that did not initiate any new activities during the initial study period (ten weeks). After the initial period, group C will begin the intervention and group E will maintain everyday activities without

  17. The effects of a muscle resistance program on the functional capacity, knee extensor muscle strength and plasma levels of IL-6 and TNF-α in pre-frail elderly women: a randomized crossover clinical trial - a study protocol

    Directory of Open Access Journals (Sweden)

    Dias João MD

    2010-07-01

    Full Text Available Abstract Background With the increase in the elderly population, a growing number of chronic degenerative diseases and a greater dependency on caregivers have been observed. Elderly persons in states of frailty remain more susceptible to significant health complications. There is evidence of an inverse relationship between plasma levels of inflammatory mediators and levels of functionality and muscle strength, suggesting that muscle-strengthening measures can aid in inflammatory conditions. The purpose of this study will be verified the effect of a muscle-strengthening program with load during a ten-week period in pre-frail elderly women with attention to the following outcomes: (1 plasma levels of interleukin-6 (IL-6 and tumor necrosis factor alpha (TNF-α, (2 functional capacity and (3 knee extensor muscle strength. Methods/Design The study design is a randomized crossover clinical trial evaluating 26 elderly women (regardless of their race and/or social condition who are community residents, older than 65, and classified as pre-frail according to the criteria previously described by Fried et al. (2004. All subjects will be assessed using the Timed up and go and 10-Meter Walk Test functional tests. The plasma levels of IL-6 and TNF-α will be assessed by ELISA (enzyme-linked immunosorbent assay with high sensitivity kits (Quantikine®HS, R&D Systems Minneapolis, MN, U.S.. Knee extensor muscle strength will be assessed using the Byodex System 3 Pro® isokinetic dynamometer at angular speeds of 60 and 180°/s. The intervention will consist of strengthening exercises of the lower extremities at 50 to 70% of 1RM (maximal resistance three times per week for ten weeks. The volunteers will be randomized into two groups: group E, the intervention group, and group C, the control group that did not initiate any new activities during the initial study period (ten weeks. After the initial period, group C will begin the intervention and group E will

  18. A unilateral open door laminoplasty technique: prospective analysis of the relationship between midline extensor muscle preservation and postoperative neck pain.

    Science.gov (United States)

    Park, Jin Hoon; Jeong, Eui-Kyun; Lee, Moon Kyu; Chul Rhim, Seung; Roh, Sung Woo; Kim, Jeoung Hee; Jeon, Sang Ryong

    2015-02-01

    Since laminoplasty was first introduced, several techniques have been developed to reduce postoperative neck pain and progressive kyphosis following this procedure. We describe the importance of deep muscle preservation to prevent postoperative neck pain following cervical posterior surgery, using the inter-muscular plane. We performed cervical laminoplasty on 10 patients from March to July 2012. The mean follow-up duration was 14.6 (range 12-18) months, and the mean age was 58.8 (48-68) years. There were eight men and two women in the study cohort, which consisted of eight cases of cervical spondylotic myelopathy and two cases of ossification of the posterior longitudinal ligament. The Japanese Orthopaedic Association (JOA) score and neck disability index (NDI) score were assessed before and at 6 and 12 months after surgery. The numeric rating scale (NRS) for neck pain was evaluated at 1, 3, 6, and 12 months after surgery. CT scan was performed immediately after the operation, and a radiograph was performed preoperatively and during the follow-up evaluation at 1, 3, 6, and 12 months after surgery. The preoperative JOA and NDI scores improved in all patients. Although there were two patients who complained of moderate postoperative neck pain (NRS 4 and 5), their condition gradually improved. Seven patients had mild or no neck pain (below NRS 3) at the 12 month follow-up. In addition, the cervical alignment was well maintained in all but one patient. Although larger prospective cohorts, longer follow-up periods, and comparative analyses are still needed, the clinical and radiological outcomes observed in the short 12 month period in this small cohort are promising. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Does intermittent pneumatic leg compression enhance muscle recovery after strenuous eccentric exercise?

    Science.gov (United States)

    Cochrane, D J; Booker, H R; Mundel, T; Barnes, M J

    2013-11-01

    Intermittent pneumatic compression (IPC) has gained rapid popularity as a post-exercise recovery modality. Despite its widespread use and anecdotal claims for enhancing muscle recovery there is no scientific evidence to support its use. 10 healthy, active males performed a strenuous bout of eccentric exercise (3 sets of 100 repetitions) followed by IPC treatment or control performed immediately after exercise and at 24 and 48 h post-exercise. Muscular performance measurements were taken prior to exercise and 24, 48 and 72 h post-exercise and included single-leg vertical jump (VJ) and peak and average isometric [knee angle 75º] (ISO), concentric (CON) and eccentric (ECC) contractions performed at slow (30° · s⁻¹) and fast (180° · s⁻¹) velocities. Plasma creatine kinase (CK) samples were taken at pre- and post-exercise 24, 48 and 72 h. Strenuous eccentric exercise resulted in a significant decrease in peak ISO, peak and average CON (30° · s⁻¹) at 24 h compared to pre-exercise for both IPC and control, however VJ performance remained unchanged. There were no significant differences between conditions (IPC and control) or condition-time interactions for any of the contraction types (ISO, CON, ECC) or velocities (CON, ECC 30° · s⁻¹ and 180° · s⁻¹). However, CK was significantly elevated at 24 h compared to pre-exercise in both conditions (IPC and control). IPC did not attenuate muscle force loss following a bout of strenuous eccentric exercise in comparison to a control. While IPC has been used in the clinical setting to treat pathologic conditions, the parameters used to treat muscle damage following strenuous exercise in healthy participants are likely to be very different than those used to treat pathologic conditions. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Fiber type composition of unoperated rat soleus and extensor digitorum longus muscles after unilateral isotransplantation of a foreign muscle in long-term experiments

    Czech Academy of Sciences Publication Activity Database

    Soukup, Tomáš; Smerdu, V.; Zachařová, Gisela

    2009-01-01

    Roč. 58, č. 2 (2009), s. 253-262 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA304/05/0327; GA ČR(CZ) GA304/08/0256; GA MŠk(CZ) LC554 Grant - others:EC(XE) LSH-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : muscle transplantations * muscle fiber types * myosin heavy chains Subject RIV: ED - Physiology Impact factor: 1.430, year: 2009

  1. 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

  2. Decreased task duration and unchanged trunk muscle activity in low-back pain patients during stair climbing after back extensor muscle fatigue

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Østergaard, Gert Værge; Brogner, Heidi Marie

    Low-back pain (LBP) is a major problem. Spine control and stability mechanisms are important but the knowledge of these parameters in functions is sparse. 7 healthy / 5 recurrent mild-to-moderate LBP patients participated in assessment of abdominal, lumbar and gluteal muscles' surface EMG and video...

  3. Stabilometric response during single-leg stance after lower limb muscle fatigue

    Directory of Open Access Journals (Sweden)

    Carlos A. V. Bruniera

    2013-10-01

    Full Text Available OBJECTIVE: This study sought to analyze the effect of muscle fatigue induced by active isotonic resistance training at a moderate intensity by measuring the knee extension motion during the stabilometric response in a single-leg stance among healthy university students who perform resistance training on a regular basis. METHOD: Eleven healthy university students were subjected to a one-repetition maximum (1RM test. In addition, stabilometric assessment was performed before and after the intervention and consisted of a muscle fatiguing protocol, in which knee extension was selected as the fatiguing task. The Shapiro-Wilk test was used to investigate the normality of the data, and the Wilcoxon test was used to compare the stabilometric parameters before and after induction of muscle fatigue, at a significance level of p≤0.05. Descriptive statistics were used in the analysis of the volunteers' age, height, body mass, and body mass index (BMI. RESULTS: The sample population was 23.1±2.7 years of age, averaged 1.79.2±0.07 m in height and 75.6±8.0 Kg in weight, and had a BMI of 23.27±3.71 Kg.m-2. The volunteers performed exercises 3.36±1.12 days/week and achieved a load of 124.54±22.07 Kg on 1RM and 74.72±13.24 Kg on 60% 1RM. The center of pressure (CoP oscillation on the mediolateral plane before and after fatigue induction was 2.89±0.89 mm and 4.09±0.59 mm, respectively, while the corresponding values on the anteroposterior plane were 2.5±2.2 mm and 4.09±2.26 mm, respectively. The CoP oscillation amplitude on the anteroposterior and mediolateral planes exhibited a significant difference before and after fatigue induction (p=0.04 and p=0.05, respectively. CONCLUSIONS: The present study showed that muscle fatigue affects postural control, particularly with the mediolateral and anteroposterior CoP excursion.

  4. Muscle glycogen content and glucose uptake during exercise in humans: influence of prior exercise and dietary manipulation

    DEFF Research Database (Denmark)

    Steensberg, Adam; van Hall, Gerrit; Keller, Charlotte

    2002-01-01

    on two occasions: one after 60 min of two-legged cycling (16 h prior to the experimental trial) followed by a high carbohydrate diet (HCHO) and the other after the same exercise followed by a low carbohydrate diet (LCHO) (Series 2). Muscle glycogen was decreased by 40 % when comparing the pre-exercised......There are many factors that can influence glucose uptake by contracting skeletal muscle during exercise and although one may be intramuscular glycogen content, this relationship is at present not fully elucidated. To test the hypothesis that muscle glycogen concentration influences glucose uptake...... during exercise, 13 healthy men were studied during two series of experiments. Seven men completed 4 h of two-legged knee extensor exercise 16 h after reducing of muscle glycogen by completing 60 min of single-legged cycling (Series 1). A further six men completed 3 h of two-legged knee extensor exercise...

  5. Placebo effect of an inert gel on experimentally induced leg muscle pain

    Directory of Open Access Journals (Sweden)

    James G Hopker

    2010-11-01

    Full Text Available James G Hopker1, Abigail J Foad2, Christopher J Beedie2, Damian A Coleman2, Geoffrey Leach11Centre for Sports Studies, University of Kent, Chatham, Kent, UK; 2Department of Sports Science, Tourism and Leisure, Canterbury Christ Church University, Canterbury, Kent, UKPurpose: This study examined the therapeutic effects of an inert placebo gel on experimentally induced muscle pain in a sports therapy setting. It aimed to investigate the degree to which conditioned analgesia, coupled with an expectation of intervention, was a factor in subsequent analgesia.Methods: Participants were sixteen male and eight female sports therapy students at a UK University. With institutional ethics board approval and following informed consent procedures, each was exposed to pain stimulus in the lower leg in five conditions, ie, conditioning, prebaseline, experimental (two placebo gel applications, and postbaseline. In conditioning trials, participants identified a level of pain stimulus equivalent to a perceived pain rating of 6/10. An inert placebo gel was then applied to the site with the explicit instruction that it was an analgesic. Participants were re-exposed to the pain stimulus, the level of which, without their knowledge, had been decreased, creating the impression of an analgesic effect resulting from the gel. In experimental conditions, the placebo gel was applied and the level of pain stimulus required to elicit a pain rating of 6/10 recorded.Results: Following application of the placebo gel, the level of pain stimulus required to elicit a pain rating of 6/10 increased by 8.2%. Application of the placebo gel significantly decreased participant’s perceptions of muscle pain (P = 0.001.Conclusion: Subjects’ experience and expectation of pain reduction may be major factors in the therapeutic process. These factors should be considered in the sports therapeutic environment.Keywords: conditioning, expectation, perception, positive belief, sports therapy

  6. Evaluation of a muscle pump-activating device for non-healing venous leg ulcers.

    Science.gov (United States)

    Harris, Connie; Duong, Rochelle; Vanderheyden, Gwen; Byrnes, Beth; Cattryse, Renee; Orr, Ava; Keast, David

    2017-12-01

    This evaluation involves an innovative muscle pump-activating device (geko™) as an adjunctive therapy with best practices for non-healing venous leg ulcers (VLUs). Stimulating the common peroneal nerve (at the fibular head), the geko™ device creates a response that acts as foot and calf muscle pumps, increasing venous, arterial and microcirculatory flow. The aim was to evaluate and determine if the geko™ is effective in this population and if it should be added to the medical supply formulary. In all, 12 patients with 18 recalcitrant VLUs (defined as less than 30% reduction in wound size in 30 days with best practices) in two community settings in Ontario consented to the evaluation and were treated with the geko™ for up to 20 weeks. A total of 44% of wounds healed, and 39% decreased in size. One patient non-adherent with the geko™ and best practices had deterioration in his or her wounds. With the patients as their own control, the mean weekly healing rate with the geko™ was 9·35% (±SD 0·10) compared to 0·06% (±SD 0·10) prior to baseline, which was statistically significant (P devices in 7 of 12 (58%) patients. One patient stopped the device due to rash, while another had to take breaks from using the device. Subsequently, the manufacturer (FirstKind Ltd) has developed a new device and protocol specific to the requirements of wound therapy to minimise this response. This small case series demonstrated the highly significant effectiveness of the geko™ device in these hard-to-heal VLUs. Further evaluations to determine dose and patient selection criteria are underway. © 2017 The Authors. International Wound Journal published by Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  7. Precooling leg muscle improves intermittent sprint exercise performance in hot, humid conditions.

    Science.gov (United States)

    Castle, Paul C; Macdonald, Adam L; Philp, Andrew; Webborn, Anthony; Watt, Peter W; Maxwell, Neil S

    2006-04-01

    We used three techniques of precooling to test the hypothesis that heat strain would be alleviated, muscle temperature (Tmu) would be reduced, and as a result there would be delayed decrements in peak power output (PPO) during exercise in hot, humid conditions. Twelve male team-sport players completed four cycling intermittent sprint protocols (CISP). Each CISP consisted of twenty 2-min periods, each including 10 s of passive rest, 5 s of maximal sprint against a resistance of 7.5% body mass, and 105 s of active recovery. The CISP, preceded by 20 min of no cooling (Control), precooling via an ice vest (Vest), cold water immersion (Water), and ice packs covering the upper legs (Packs), was performed in hot, humid conditions (mean +/- SE; 33.7 +/- 0.3 degrees C, 51.6 +/- 2.2% relative humidity) in a randomized order. The rate of heat strain increase during the CISP was faster in Control than Water and Packs (P body or whole body cooling.

  8. Leg muscle mass and composition in relation to lower extremity performance in men and women aged 70 to 79 : the health, aging and body composition study

    NARCIS (Netherlands)

    Visser, Marjolein; Kritchevsky, Stephen B; Goodpaster, Bret H; Newman, Anne B; Nevitt, Michael; Stamm, Elizabeth; Harris, Tamara B

    OBJECTIVES: The loss of muscle mass with aging, or sarcopenia, is hypothesized to be associated with the deterioration of physical function. Our aim was to determine whether low leg muscle mass and greater fat infiltration in the muscle were associated with poor lower extremity performance (LEP).

  9. Muscle activity during leg strengthening exercise using free weights and elastic resistance: effects of ballistic vs controlled contractions.

    Science.gov (United States)

    Jakobsen, Markus Due; Sundstrup, Emil; Andersen, Christoffer H; Aagaard, Per; Andersen, Lars L

    2013-02-01

    The present study's aim was to evaluate muscle activity during leg exercises using elastic vs. isoinertial resistance at different exertion and loading levels, respectively. Twenty-four women and eighteen men aged 26-67 years volunteered to participate in the experiment. Electromyographic (EMG) activity was recorded in nine muscles during a standardized forward lunge movement performed with dumbbells and elastic bands during (1) ballistic vs. controlled exertion, and (2) at low, medium and high loads (33%, 66% and 100% of 10 RM, respectively). The recorded EMG signals were normalized to MVC EMG. Knee joint angle was measured using electronic inclinometers. The following results were obtained. Loading intensity affected EMG amplitude in the order: lowBallistic contractions always produced greater EMG activity than slow controlled contractions, and for most muscles ballistic contractions with medium load showed similar EMG amplitude as controlled contractions with high load. At flexed knee joint positions with elastic resistance, quadriceps and gluteus EMG amplitude during medium-load ballistic contractions exceeded that recorded during high-load controlled contractions. Quadriceps and gluteus EMG amplitude increased at flexed knee positions. In contrast, hamstrings EMG amplitude remained constant throughout ROM during dumbbell lunge, but increased at more extended knee joint positions during lunges using elastic resistance. Based on these results, it can be concluded that lunges performed using medium-load ballistic muscle contractions may induce similar or even higher leg muscle activity than lunges using high-load slow-speed contractions. Consequently, lunges using elastic resistance appear to be equally effective in inducing high leg muscle activity as traditional lunges using isoinertial resistance. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Focal vibration of quadriceps muscle enhances leg power and decreases knee joint laxity in female volleyball players.

    Science.gov (United States)

    Brunetti, O; Botti, F M; Roscini, M; Brunetti, A; Panichi, R; Filippi, G M; Biscarini, A; Pettorossi, V E

    2012-12-01

    This double-blind randomized controlled study aims at determining the effect of repeated muscle vibration (rMV) on explosive and reactive leg power and on knee laxity of female volleyball players. Eighteen voluntary volleyball athletes, belonging to the same senior regional level team (age=22.7 ± 3 years, height=180.3 ± 5 cm, mass= 64 ± 4 kg) were assigned to three groups (N.=6) for vibration on contracted quadriceps (VC), vibration on relaxed muscle (VR), and sham vibration (NV), respectively. Intervention consisted in 3 rMV sessions performed in 3 consecutive days. In each session, 100 Hz, 300-500 μm amplitude vibratory stimuli were bilaterally delivered to the quadriceps in three consecutive 10-minutes applications. Explosive and reactive leg power and knee joint laxity were evaluated 1 day before, and 1, 30, and 240 days after intervention. In VC group, explosive and reactive leg power increased respectively by ~16% and ~9% at 1 day, by ~19% and ~11% at 30 days and by ~26% and ~13% at 240 days, concomitantly knee laxity decreased by ~6%, ~15% and ~18% at the same times. These changes were significantly larger than in the other groups, in which leg power increment and knee joint laxity reduction remained close to ~3%, ~5% and ~10% at 1, 30 and 240 days, respectively. Combined bilateral voluntary contraction and rMV of the quadriceps muscles is a short-lasting, non-invasive technique that can significantly and persistently improve muscle performance and knee laxity in volleyball women players.

  11. Near-Infrared Spectroscopic Measurement of the Effect of Leg Dominance on Muscle Oxygen Saturation During Cycling

    Science.gov (United States)

    Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.

    2011-01-01

    The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of

  12. Pharmacological enhancement of leg and muscle microvascular blood flow does not augment anabolic responses in skeletal muscle of young men under fed conditions.

    Science.gov (United States)

    Phillips, Bethan E; Atherton, Philip J; Varadhan, Krishna; Wilkinson, Daniel J; Limb, Marie; Selby, Anna L; Rennie, Michael J; Smith, Kenneth; Williams, John P

    2014-01-15

    Skeletal muscle anabolism associated with postprandial plasma aminoacidemia and insulinemia is contingent upon amino acids (AA) and insulin crossing the microcirculation-myocyte interface. In this study, we hypothesized that increasing muscle microvascular blood volume (flow) would enhance fed-state anabolic responses in muscle protein turnover. We studied 10 young men (23.2 ± 2.1 yr) under postabsorptive and fed [iv Glamin (∼10 g AA), glucose ∼7.5 mmol/l] conditions. Methacholine was infused into the femoral artery of one leg to determine, via bilateral comparison, the effects of feeding alone vs. feeding plus pharmacological vasodilation. We measured leg blood flow (LBF; femoral artery) by Doppler ultrasound, muscle microvascular blood volume (MBV) by contrast-enhanced ultrasound (CEUS), muscle protein synthesis (MPS) and breakdown (MPB; a-v balance modeling), and net protein balance (NPB) using [1,2-(13)C2]leucine and [(2)H5]phenylalanine tracers via gas chromatography-mass spectrometry (GC-MS). Indexes of anabolic signaling/endothelial activation (e.g., Akt/mTORC1/NOS) were assessed using immunoblotting techniques. Under fed conditions, LBF (+12 ± 5%, P anabolism.

  13. Sex Comparison of Knee Extensor Size, Strength and Fatigue Adaptation to Sprint Interval Training.

    Science.gov (United States)

    Bagley, Liam; Al-Shanti, Nasser; Bradburn, Steven; Baig, Osamah; Slevin, Mark; McPhee, Jamie S

    2018-03-12

    Regular sprint interval training (SIT) improves whole-body aerobic capacity and muscle oxidative potential, but very little is known about knee extensor anabolic or fatigue resistance adaptations, or whether effects are similar for males and females. The purpose of this study was to compare sex-related differences in knee extensor size, torque-velocity relationship and fatigability adaptations to 12 weeks SIT. Sixteen males and fifteen females (mean (SEM) age: 41 (±2.5) yrs) completed measurements of total body composition assessed by DXA, quadriceps muscle cross-sectional area (CSAQ) assessed by MRI, the knee extensor torque-velocity relationship (covering 0 - 240°·sec) and fatigue resistance, which was measured as the decline in torque from the first to the last of 60 repeated concentric knee extensions performed at 180°·sec. SIT consisted of 4 x 20 second sprints on a cycle ergometer set at an initial power output of 175% of power at VO2max, three times per week for 12 weeks. CSAQ increased by 5% (p=0.023) and fatigue resistance improved 4.8% (p=0.048), with no sex differences in these adaptations (sex comparisons: p=0.140 and p=0.282, respectively). Knee extensor isometric and concentric torque was unaffected by SIT in both males and females (p>0.05 for all velocities). 12 weeks SIT, totalling 4 minutes very intense cycling per week, significantly increased fatigue resistance and CSAQ similarly in males and females, but did not significantly increase torque in males or females. These results suggest that SIT is a time-effective training modality for males and females to increase leg muscle size and fatigue resistance.

  14. Timing of muscle response to a sudden leg perturbation: comparison between adolescents and adults with Down syndrome.

    Directory of Open Access Journals (Sweden)

    Maria Stella Valle

    Full Text Available Movement disturbances associated with Down syndrome reduce mechanical stability, worsening the execution of important tasks such as walking and upright standing. To compensate these deficits, persons with Down syndrome increase joint stability modulating the level of activation of single muscles or producing an agonist-antagonist co-activation. Such activations are also observed when a relaxed, extended leg is suddenly released and left to oscillate passively under the influence of gravity (Wartenberg test. In this case, the Rectus femoris of adults with Down syndrome displayed peaks of activation after the onset of the first leg flexion. With the aim to verify if these muscular reactions were acquired during the development time and to find evidences useful to give them a functional explanation, we used the Wartenberg test to compare the knee joint kinematics and the surface electromyography of the Rectus femoris and Biceps femoris caput longus between adolescents and adults with Down syndrome. During the first leg flexion, adolescents and adults showed single Rectus femoris activations while, a restricted number of participants exhibited agonist-antagonist co-activations. However, regardless the pattern of activation, adults initiated the muscle activity significantly later than adolescents. Although most of the mechanical parameters and the total movement variability were similar in the two groups, the onset of the Rectus femoris activation was well correlated with the time of the minimum acceleration variability. Thus, in adolescents the maximum mechanical stability occurred short after the onset of the leg fall, while adults reached their best joint stability late during the first flexion. These results suggest that between the adolescence and adulthood, persons with Down syndrome explore a temporal window to select an appropriate timing of muscle activation to overcome their inherent mechanical instability.

  15. Exercise induces transient transcriptional activation of the PGC-1a gene in human skeletal muscle

    DEFF Research Database (Denmark)

    Pilegaard, Henriette; Saltin, Bengt; Neufer, P. Darrell

    2003-01-01

    Endurance exercise training induces mitochondrial biogenesis in skeletal muscle. The peroxisome proliferator activated receptor co-activator 1a (PGC-1a) has recently been identified as a nuclear factor critical for coordinating the activation of genes required for mitochondrial biogenesis in cell...... culture and rodent skeletal muscle. To determine whether PGC-1a transcription is regulated by acute exercise and exercise training in human skeletal muscle, seven male subjects performed 4 weeks of one-legged knee extensor exercise training. At the end of training, subjects completed 3 h of two......-legged knee extensor exercise. Biopsies were obtained from the vastus lateralis muscle of both the untrained and trained legs before exercise and after 0, 2, 6 and 24 h of recovery. Time to exhaustion (2 min maximum resistance), as well as hexokinase II (HKII), citrate synthase and 3-hydroxyacyl...

  16. Ultrasound measurement of the size of the anterior tibial muscle group: the effect of exercise and leg dominance

    LENUS (Irish Health Repository)

    McCreesh, Karen

    2011-09-13

    Abstract Background Knowledge of normal muscle characteristics is crucial in planning rehabilitation programmes for injured athletes. There is a high incidence of ankle and anterior tibial symptoms in football players, however little is known about the effect of limb dominance on the anterior tibial muscle group (ATMG). The purpose of this study was to assess the effect of limb dominance and sports-specific activity on ATMG thickness in Gaelic footballers and non-football playing controls using ultrasound measurements, and to compare results from transverse and longitudinal scans. Methods Bilateral ultrasound scans were taken to assess the ATMG size in 10 Gaelic footballers and 10 sedentary controls (age range 18-25 yrs), using a previously published protocol. Both transverse and longitudinal images were taken. Muscle thickness measurements were carried out blind to group and side of dominance, using the Image-J programme. Results Muscle thickness on the dominant leg was significantly greater than the non-dominant leg in the footballers with a mean difference of 7.3%, while there was no significant dominance effect in the controls (p < 0.05). There was no significant difference between the measurements from transverse or longitudinal scans. Conclusions A significant dominance effect exists in ATMG size in this group of Gaelic footballers, likely attributable to the kicking action involved in the sport. This should be taken into account when rehabilitating footballers with anterior tibial pathology. Ultrasound is a reliable tool to measure ATMG thickness, and measurement may be taken in transverse or longitudinal section.

  17. Intramuscular fatty acid metabolism in contracting and non-contracting human skeletal muscle

    DEFF Research Database (Denmark)

    Sacchetti, M; Saltin, B; Osada, T

    2002-01-01

    The present study was undertaken to investigate the fate of blood-borne non-esterified fatty acids (NEFA) entering contracting and non-contracting knee extensor muscles of healthy young individuals. [U-(13)C]-palmitate was infused into a forearm vein during 5 h of one-legged knee extensor exercis...... and degraded and that the metabolic fate of plasma NEFA entering the muscle is influenced by muscle contraction, so that a higher proportion is directed towards oxidation at the expense of storage in mTAG.......The present study was undertaken to investigate the fate of blood-borne non-esterified fatty acids (NEFA) entering contracting and non-contracting knee extensor muscles of healthy young individuals. [U-(13)C]-palmitate was infused into a forearm vein during 5 h of one-legged knee extensor exercise.......05) in the contracting muscle, whereas it was unchanged in the non-contracting muscle. The uptake of plasma NEFA, as well as the proportion directed towards oxidation, was higher in the exercising compared to the non-exercising leg, whereas the rate of palmitate incorporation into mTAG was fourfold lower (0.70 +/- 0...

  18. Leg and trunk muscle coordination and postural sway during increasingly difficult standing balance tasks in young and older adults.

    Science.gov (United States)

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

    2016-09-01

    Ageing impairs body balance and increases older adults' fall risk. Balance training can improve intrinsic fall risk factors. However, age comparisons of muscle activity responses during balance tasks are lacking. This study investigated relative muscle activity, muscle coordination and postural sway during various recommended static balance training tasks. Muscle activity (%MVC), amplitude ratios (AR) and co-activity (CAI) were determined during standing tasks for 30s (1: double limb stance on a foam surface, eyes open; 2: double limb stance on firm ground, eyes closed; 3: double limb stance, feet in step position on a foam surface, eyes open; 4: double limb stance, feet in step position on firm ground, eyes closed; 5: single limb stance on firm ground, eyes open) in 20 healthy young adults (24±2 y) and 20 older adults (73±6 y). Surface electromyography (SEMG) was applied (SENIAM guidelines) to ankle (tibialis anterior, soleus, medial gastrocnemius, peroneus longus) and thigh (vastus lateralis, vastus medialis, biceps femoris, semitendinosus) muscles (non-dominant leg). Electrodes over trunk (multifidus and internal oblique) muscles were applied bilaterally. Two- to six-fold higher levels of relative muscle activity were found in older adults for ankle (0.0002adults for the trunk (0.001older adults for the ankle (0.009Older adults had higher electrophysiological costs for all stance conditions. Muscle coordination showed inverse activity patterns at the ankle and trunk. Optimal balance and strength training programs should take into account age-specific alterations in muscle activity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Ballistic movements of jumping legs implemented as variable components of cricket behaviour.

    Science.gov (United States)

    Hustert, R; Baldus, M

    2010-12-01

    Ballistic accelerations of a limb or the whole body require special joint mechanisms in many animals. Specialized joints can be moved by stereotypic or variable motor control during motor patterns with and without ballistic components. As a model of variable motor control, the specialized femur-tibia (knee) joints of cricket (Acheta domesticus) hindlegs were studied during ballistic kicking, jumping and swimming and in non-ballistic walking. In this joint the tendons of the antagonistic flexor and the extensor muscles attach at different distances from the pivot and the opposed lever arms form an angle of 120 deg. A 10:1 ratio of their effective lever arms at full knee flexion helps to prepare for most ballistic extensions: the tension of the extensor can reach its peak while it is restrained by flexor co-contraction. In kicks, preparatory flexion is rapid and the co-contraction terminates just before knee extensions. Therefore, mainly the stored tension of the extensor muscle accelerates the small mass of the tibia. Jumps are prepared with slower extensor-flexor co-contractions that flex both knees simultaneously and then halt to rotate both legs outward to a near horizontal level. From there, catapult extension of both knees accelerates the body, supported by continued high frequency motor activity to their tibia extensor muscles during the ongoing push-off from the substrate. Premature extension of one knee instantly takes load from the lagging leg that extends and catches up, which finally results in a straight jump. In swimming, synchronous ballistic power strokes of both hindlegs drive the tibiae on a ventral-to-posterior trajectory through the water, well coordinated with the swimming patterns of all legs. In walking, running and climbing the steps of the hindlegs range between 45 deg flexion and 125 deg extension and use non-ballistic, alternating activity of knee flexor and extensor muscles. Steep climbing requires longer bursts from the extensor tibiae

  20. Muscle ion transporters and antioxidative proteins have different adaptive potential in arm than in leg skeletal muscle with exercise training

    DEFF Research Database (Denmark)

    Mohr, Magni; Nielsen, Tobias Schmidt; Weihe, Pál

    2017-01-01

    for 15 weeks, and pre- and postintervention biopsies were obtained from deltoideus and vastus lateralis muscle. Before training, monocarboxylate transporter 4 (MCT4), Na(+)/K(+) pump α2, and superoxide dismutase 2 (SOD2) expressions were lower (P ... occurred exclusively in vastus lateralis muscle. The increased (P MCT4 and SOD2 in deltoid muscle after HIS and vastus lateralis muscle after SOC were similar. In conclusion, arm musculature displays lower basal ROS, La(-), K(+) handling capability but higher Na(+)-dependent H...

  1. Effect of a patella support brace on myoelectric activity of knee joint muscles during single leg landing

    Directory of Open Access Journals (Sweden)

    Fatemeh Salariesker

    2013-06-01

    Full Text Available Introduction: Patellfemoral pain syndrome is one of the most common knee joint problems that affect athletes and non-athletes. Knee brace is often used as a treatment method for patellar realignment. The aim of the present study was to determine the effects of a patella support brace on myoelectric activity of selected knee muscles during single leg landing in healthy females. Materials and Methods: 19 healthy female students (Mean age: 23.6±1.98 years, height: 163.5±5.88 cm, weight: 62.3±3.6 kg participated in this study. Myoelectric activity of biceps femoris, semitendinosus, vastus medialis and vastus lateralis were collected during single leg landing in with and without using the patella support brace conditions.Results: Use of the patella support brace had no significant effect on myoelectric activity for the semitendinosus (p=0.668, vastus medialis (VM (p=0.915 and vastus lateralis (VL (P=0.134, while myoelectric activity for biceps femoris (p=0.005 and ratio of VM/VL myoelectric activity significantly increased (p=0.045. Conclusion: Our results revealed that biceps femoris activity and vastus medialis/vastus lateralis ratio increased after using patella support brace during single leg landing. Further studies on kinematic and kinetic variables are needed to describe these changes in muscular activity when using the patella support brace.

  2. Reduced glycogen availability is associated with an elevation in HSP72 in contracting human skeletal muscle

    DEFF Research Database (Denmark)

    Febbraio, Mark A; Steensberg, Adam; Walsh, Rory

    2002-01-01

    To test the hypothesis that a decrease in intramuscular glycogen availability may stimulate heat shock protein expression, seven men depleted one leg of muscle glycogen the day before performing 4-5 h of exhaustive, two-legged knee extensor exercise at 40 % of leg peak power output. Subjects...... and both femoral veins and blood was sampled from these catheters prior to exercise and at 1 h intervals during exercise and into recovery for the measurement of arterial-venous differences in serum HSP72. Plasma creatine kinase (CK) was also measured from arterial blood samples. Pre-exercise muscle...

  3. The validity of anthropometric leg muscle volume estimation across a wide spectrum: from able-bodied adults to individuals with a spinal cord injury.

    Science.gov (United States)

    Layec, Gwenael; Venturelli, Massimo; Jeong, Eun-Kee; Richardson, Russell S

    2014-05-01

    The assessment of muscle volume, and changes over time, have significant clinical and research-related implications. Methods to assess muscle volume vary from simple and inexpensive to complex and expensive. Therefore this study sought to examine the validity of muscle volume estimated simply by anthropometry compared with the more complex proton magnetic resonance imaging ((1)H-MRI) across a wide spectrum of individuals including those with a spinal cord injury (SCI), a group recognized to exhibit significant muscle atrophy. Accordingly, muscle volume of the thigh and lower leg of eight subjects with a SCI and eight able-bodied subjects (controls) was determined by anthropometry and (1)H-MRI. With either method, muscle volumes were significantly lower in the SCI compared with the controls (P muscle volume were strongly correlated to the values assessed by (1)H-MRI in both the thigh (r(2) = 0.89; P muscle volume compared with (1)H-MRI in both the thigh (mean bias = 2407cm(3)) and the lower (mean bias = 170 cm(3)) leg. Thus with an appropriate correction for this systemic overestimation, muscle volume estimated from anthropometric measurements is a valid approach and provides acceptable accuracy across a spectrum of adults with normal muscle mass to a SCI and severe muscle atrophy. In practical terms this study provides the formulas that add validity to the already simple and inexpensive anthropometric approach to assess muscle volume in clinical and research settings.

  4. Relations Between Lower Body Isometric Muscle Force Characteristics and Start Performance in Elite Male Sprint Swimmers

    Directory of Open Access Journals (Sweden)

    Igor Beretić

    2013-12-01

    Full Text Available The aim of the present study was twofold. The first aim was to examine the influence of absolute and relative lower body muscle force on kinematic component which determine the start performance. The second aim was to create multiregressional model which could use as a tool for swimming coaches with the purpose to start performance control and improvement. Twenty seven high-level trained male competitive swimmers all members of the Serbian National Youth and Senior Swimming Team (Age = 21.1 ± 4.3 yrs., Height = 1. 89 ± 0.10 m, Weight = 81.6 ± 8.4 kg, 50m freestyle - long course = 24.36 ± 0.86 s performed two trials of standing leg extensors isometric muscle force testing and three swimming start trials corresponding to 10m distance. The average start time significantly correlated with variables of leg extensors maximum voluntary force (Fmax, r = -0.559, p = 0.002, leg extensors relative muscle voluntary force (Frel, r = -0.727, p < 0.001, leg extensors specific rate of force development (RFD50%, r = -0.338, p = 0.047 and leg extensors relative value of specific rate of force development (RFD50%rel, r = -0.402, p = 0.040. Regression equation for t10m prediction was defined by following variables: maximum voluntary isometric force of leg extensors muscles at absolute and relative level (Fmax and Frel, as well as a specific rate of force development of the same muscle groups (RFD50% and RFD50%rel at absolute and relative level too with 74.4% of explained variance. Contractile abilities indicators of the leg extensors muscles included consideration: Fmax, RFD50%, Frel and RFD50%rel showed significant correlation with swimming start times on 10m. Additionally, the results suggest that swimmers, who possess greater isometric maximum force and specific rate of force development at absolute and relative levels, tend to be able to swim faster on initial 10m swim start perforamnce.

  5. The effects of gender, level of co-contraction, and initial angle on elbow extensor muscle stiffness and damping under a step increase in elbow flexion moment.

    Science.gov (United States)

    Lee, Yunju; Ashton-Miller, James A

    2011-10-01

    Flexion buckling of an arm under the large ground reaction loads associated with arresting a fall to the ground increases the risk for head and thorax injuries. Yet, the factors that determine the arm buckling load remain poorly understood. We tested the hypothesis in 18 healthy young adults that neither gender, triceps co-contraction level (i.e., 25, 50, or 75% MVC) nor elbow angle would affect the rotational stiffness and damping resistance to step changes in elbow flexion loading. Data on the step response were gathered using optoelectronic markers (150 Hz) and myoelectric activity measurements (2 kHz), and an inverse dynamics analysis was used to estimate elbow extensor stiffness and damping coefficients. A repeated-measures analysis of variance showed that gender (p = 0.032), elbow flexion angle and co-contraction level (both p initial elbow flexion angle and maximum co-contraction, female stiffness and damping coefficients were 18 and 30% less, respectively, than male values after normalization by body height and weight. We conclude that the maximum extensor rotational stiffness and damping at the elbow is lower in women than in men of the same body size, and varies with triceps co-contraction level and initial elbow angle.

  6. Straight-leg rasing in 'short hamstrings'. An experimental study of muscle elasticy and defense reactions.

    NARCIS (Netherlands)

    Göeken, Ludwig Nanno Hiltjo

    1988-01-01

    The central guestion asked in this thesis is whether an Experimental Straight-Leg Raising test (E.S.L.R.) can contribute to the solution of a diagnostical problem frequently encountered in rehabilitation medicine. It concerns the determination of the cause of the movement restriction in patients who

  7. Relation between knee extensors' strength, postural stability and variability of centre of pressure displacement during gait in adult women

    Directory of Open Access Journals (Sweden)

    Eliza C. de Souza

    2017-03-01

    Full Text Available Background: It has been shown that variability of walking is related to fall risk similarly as postural control and muscle strength. Joint potential of this group of variables for fall risk assessment is promising, however research interested in relations between them is lacking. Objective: The aim of this study was to investigate the relation between knee extensors' strength, centre of pressure (COP velocity during one-leg stance and variability of COP displacement during various phases of gait cycle in middle-age women. Methods: A single group of 40 healthy women (age 56 ± 4.2 years took part in the study. For assessment of knee extensors' strength (peak torque and average work during concentric and eccentric contractions an isokinetic dynamometer was used. Mean velocity of COP during one-leg stance in anterior-posterior (AP and medial-lateral (ML directions was assessed on a force plate on a rigid surface with eyes open (two 30 s trials. Variability of COP displacement was assessed for loading response, midstance, terminal stance and preswing gait cycle phases (determined by vertical ground reaction force in AP and ML directions. It was measured by two force plates positioned in the middle of an 8 m walkway (5 trials at a self-selected speed. For statistical analysis of relationships between variables Pearson correlation was applied. Results: Our results showed significant correlations between eccentric peak torque and COP velocity in AP direction during one-leg stance, eccentric and concentric peak torque and COP variability during loading response in both ML and AP directions and during terminal stance in AP direction. Conclusion: Loading response and terminal stance seems to be more related to knee extensors' strength. Variables derived from postural stability assessment during one-leg stance are independent from variables derived from assessment of COP displacement variability during walking.

  8. Human skeletal muscle fatty acid and glycerol metabolism during rest, exercise and recovery

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Sacchetti, M; Rådegran, G

    2002-01-01

    glycerol uptake was observed, which was substantially higher during exercise. Total body skeletal muscle FA and glycerol uptake/release was estimated to account for 18-25 % of whole body R(d) or R(a). In conclusion: (1) skeletal muscle FA and glycerol metabolism, using the leg arterial-venous difference......This study was conducted to investigate skeletal muscle fatty acid (FA) and glycerol kinetics and to determine the contribution of skeletal muscle to whole body FA and glycerol turnover during rest, 2 h of one-leg knee-extensor exercise at 65 % of maximal leg power output, and 3 h of recovery....... To this aim, the leg femoral arterial-venous difference technique was used in combination with a continuous infusion of [U-(13)C]palmitate and [(2)H(5)]glycerol in five post-absorptive healthy volunteers (22 +/- 3 years). The influence of contamination from non-skeletal muscle tissues, skin and subcutaneous...

  9. MRI-based screening for metabolic insufficiency of leg muscle during aerobic exercise in Cystic Fibrosis

    NARCIS (Netherlands)

    Jeneson, J.A.L.; Werkman, M.S.; Blanken, N.; Oorschot, van J.W.M.; Ent, van der K.; Arets, H.G.; Hulzebos, H.J.; Takken, T.

    2012-01-01

    There is evidence for mitochondrial dysfunction in various tissues in Cystic Fibrosis (CF) including muscle. Among others, a slow rate of high-energy phosphate resynthesis following exercise involving single limb muscle activity was found in human CF using in vivo 31P magnetic resonance spectroscopy

  10. Training affects muscle phospholipid fatty acid composition in humans

    DEFF Research Database (Denmark)

    Helge, Jørn Wulff; Wu, B J; Willer, Mette

    2001-01-01

    on the muscle membrane phospholipid fatty acid composition in humans. Seven male subjects performed endurance training of the knee extensors of one leg for 4 wk. The other leg served as a control. Before, after 4 days, and after 4 wk, muscle biopsies were obtained from the vastus lateralis. After 4 wk......, the phospholipid fatty acid contents of oleic acid 18:1(n-9) and docosahexaenoic acid 22:6(n-3) were significantly higher in the trained (10.9 +/- 0.5% and 3.2 +/- 0.4% of total fatty acids, respectively) than the untrained leg (8.8 +/- 0.5% and 2.6 +/- 0.4%, P fatty acids...... was significantly lower in the trained (11.1 +/- 0.9) than the untrained leg (13.1 +/- 1.2, P fatty acid composition. Citrate synthase activity was increased by 17% in the trained compared with the untrained leg (P

  11. Efeitos da crioterapia e facilitação neuromuscular proprioceptiva sobre a força muscular nas musculaturas flexora e extensora de joelho Effects of cryotherapy and proprioceptive neuromuscular facilitation on muscle strength at the flexor and extensor muscles of the knee

    Directory of Open Access Journals (Sweden)

    Daiana Moreira Mortari

    2009-12-01

    Full Text Available As musculaturas flexora e extensora do joelho são freqüentemente lesionadas devido a um desequilíbrio entre esses grupos. Recursos térmicos, como a crioterapia, e técnicas de alongamento, como a técnica mantém-relaxa da facilitação neuromuscular proprioceptiva (FNP, influenciam a flexibilidade e força muscular, proporcionando maior homogeneidade entre essas musculaturas e diminuindo a incidência de lesões. Este estudo objetivou verificar os efeitos da crioterapia e da FNP sobre a força das musculaturas flexora e extensora de joelho. A amostra foi composta por 18 mulheres com idade entre 18 e 24 anos, não-praticantes de atividade física regular, divididas em dois grupos: um submetido a crioterapia e o outro à técnica mantém-relaxa da FNP. Antes e após uma sessão de aplicação das técnicas foi feita avaliação isocinética. A aplicação da técnica mantém-relaxa provocou aumento da força em ambas as musculaturas em ambos os membros, atingindo nível de significância nos flexores do membro inferior direito (p=0,04. A crioterapia diminuiu a força dos extensores e exerceu efeito contrário sobre os flexores, tendo gerado aumento significativo nos flexores do membro inferior direito (p=0,035. Quando comparadas as técnicas, a técnica mantém-relaxa gerou maiores valores de pico de torque, principalmente nos extensores do membro inferior esquerdo (p=0,042. Conclui-se que a técnica mantém-relaxa da FNP gerou maiores valores no pico de torque em relação à crioterapia.Knee extensor and flexor muscles are often injured due to an imbalance between these groups, which may lead to a deficit in muscle performance. Thermal resources, such as cryotherapy, and stretching techniques, such as the "hold-relax" of proprioceptive neuromuscular facilitation (PNF, influence flexibility and muscle strength and may reduce the chances of muscle tendon injuries. The aim of the study was to verify the effects of cryotherapy and of the PNF

  12. Monitoring of color and pH in muscles of pork leg (m. adductor and m. semimembranosus

    Directory of Open Access Journals (Sweden)

    Martina Bednářová

    2014-02-01

    Full Text Available In order to identify PSE pork meat, pH and color testing was performed directly in a cutting plant (72 hours post mortem in this research. Specifically pork leg muscles musculi adductor (AD and semimembranosus (SM from five selected suppliers (A, B, C, D, E were examined. Twenty samples of meat for each muscle were examined from each supplier. The measured pH values ranged from 5.43 to 5.63, and the L* values from 46.13 to 57.18. No statistically significant differences in pH values and color were detected among the various suppliers with the exception of the a* and b* parameters for two suppliers, namely A and B (p<0.01. On the contrary, a statistically significant difference (p<0.5 was recorded between individual muscles (AD/SM across all the suppliers (A, B, C, D, E with the exception of a* parameter from suppliers B, C, D, E, and pH values for the E supplier. Our results revealed that individual muscles differ in values of pH and color. In comparison with literature, pH and lightness L* values in musculus adductor point to PSE (pale, soft and exudative meat, while the values of musculus semimebranosus to RFN (red, firm and non-exudative. Use of PSE meat in production of meat products can cause several problems. In particular, it causes light color, low water-holding capacity, poor fat emulsifying ability, lower yield, granular or crumbly texture and poor consistency of the finished product. Therefore classification of the meat directly cutting plant may be possible solution for this problem. The finished product pruduces from muscles of musculi semimembranosus can obtain better quality than the finished product from musculi adductor.

  13. Effect of pillow size preference on extensor digitorum communis muscle strength and electromyographic activity during maximal contraction in healthy individuals: A pilot study

    Directory of Open Access Journals (Sweden)

    Jia-Chi Wang

    2015-03-01

    Conclusion: The results suggest that anatomical body measurements are not good predictors of optimal pillow height. As EDC muscle strength is affected by pillow height preference, maximal EDC muscle strength may be a useful complement for selecting the optimal pillow size.

  14. Contribution of Leg-Muscle Forces to Paddle Force and Kayak Speed During Maximal-Effort Flat-Water Paddling.

    Science.gov (United States)

    Nilsson, Johnny E; Rosdahl, Hans G

    2016-01-01

    The purpose was to investigate the contribution of leg-muscle-generated forces to paddle force and kayak speed during maximal-effort flat-water paddling. Five elite male kayakers at national and international level participated. The participants warmed up at progressively increasing speeds and then performed a maximal-effort, nonrestricted paddling sequence. This was followed after 5 min rest by a maximal-effort paddling sequence with the leg action restricted--the knee joints "locked." Left- and right-side foot-bar and paddle forces were recorded with specially designed force devices. In addition, knee angular displacement of the right and left knees was recorded with electrogoniometric technique, and the kayak speed was calculated from GPS signals sampled at 5 Hz. The results showed that reduction in both push and pull foot-bar forces resulted in a reduction of 21% and 16% in mean paddle-stroke force and mean kayak speed, respectively. Thus, the contribution of foot-bar force from lower-limb action significantly contributes to kayakers' paddling performance.

  15. Characteristics and preliminary observations of the influence of electromyostimulation on the size and function of human skeletal muscle during 30 days of simulated microgravity

    Science.gov (United States)

    Duvoisin, Marc R.; Convertino, Victor A.; Buchanan, Paul; Gollnick, Philip A.; Dudley, Gary A.

    1989-01-01

    The effect of transcutaneous electromyostimulation (EMS) on the development of atrophy and the loss of strength in lower limb musculature in humans exposed to microgravity was determined in three subjects who received EMS twice daily in a 3-d on/1-d off cycle on their dominant leg during 30 days of bedrest. The output waveform from the stimulator was sequenced to the knee extensors, knee flexors, ankle extensors, and ankle flexors, and caused three isometric contractions of each muscle group per minute. It was found that, in the dominant leg, EMS acted to attenuate the changes caused by bedrest, such as reductions in the leg volume, muscle compartment size, cross-sectional area of slow- and fast-twitch fibers, strength, and aerobic enzyme activities, and an increase in leg compliance.

  16. Trunk and hip muscle recruitment patterns during the prone leg extension following a lateral ankle sprain: A prospective case study pre and post injury

    Directory of Open Access Journals (Sweden)

    Lehman Gregory J

    2006-02-01

    Full Text Available Abstract Background and case presentation The prone leg extension (PLE is commonly used to identify dysfunction of muscle recruitment patterns. The prone leg extension is theorized to identify proximal muscle disturbances which are a result of distal injury or dysfunction (i.e. an ankle sprain. This case study compares the trunk and hip muscle (bilateral lower erector spine, ipsilateral hamstring and ipsilateral gluteus maximus timing during a PLE of a 27 year old female runner during a healthy state (pre ankle sprain and 2 and 8 weeks post ankle sprain. Results and discussion The gluteus maximus muscle onsets at 8 weeks post injury appeared to occur earlier compared with 2 weeks post injury. The Right Erector Spinae at 8 weeks post injury was also active earlier compared with the participant's non-injured state. A large degree of variability can be noted within trials on the same day for all muscle groups. Conclusion An acute ankle injury did not result in a delay in gluteus maximus muscle activation. The utility of the prone leg extension as a clinical and functional test is questionable due to the normal variability seen during the test and our current inability to determine what is normal and what is dysfunctional.

  17. Impact of a single session of intermittent pneumatic leg compressions on skeletal muscle and isolated artery gene expression in rats.

    Science.gov (United States)

    Roseguini, Bruno T; Arce-Esquivel, Arturo A; Newcomer, Sean C; Laughlin, M H

    2011-12-01

    Intermittent pneumatic leg compressions (IPC) have proven to be an effective noninvasive approach for treatment of patients with claudication, but the mechanisms underlying the clinical benefits remain elusive. In the present study, a rodent model of claudication produced by bilateral ligation of the femoral artery was used to investigate the acute impact of a single session of IPC (150 min) on hemodynamics, skeletal muscle (tibialis anterior), and isolated collateral artery (perforating artery) expression of a subset of genes associated with inflammation and vascular remodeling. In addition, the effect of compression frequency (15 vs. 3 compressions/min) on the expression of these factors was studied. In ligated animals, IPC evoked an increase of monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant 1 (CXCL1) mRNA (P < 0.01) and immunostaining (P < 0.05), as well as a minor increase in VEGF immunostaining in the muscle endomysium 150 min postintervention. Further, collateral arteries from these animals showed an increased expression of MCP-1 (approximately twofold, P = 0.02). These effects were most evident in the group exposed to the high-frequency protocol (15 compressions/min). In contrast, IPC in sham-operated control animals evoked a modest initial upregulation of VEGF (P = 0.01), MCP-1 (P = 0.02), and CXCL1 (P = 0.03) mRNA in the muscle without concomitant changes in protein levels. No changes in gene expression were observed in arteries isolated from sham animals. In conclusion, IPC acutely up-regulates the expression of important factors involved in vascular remodeling in the compressed muscle and collateral arteries in a model of hindlimb ischemia. These effects appear to be dependent on the compression frequency, such that a high compression frequency (15 compressions/min) evokes more consistent and robust effects compared with the frequency commonly employed clinically to treat patients with claudication (3

  18. Improvement in upper leg muscle strength underlies beneficial effects of exercise therapy in knee osteoarthritis: secondary analysis from a randomised controlled trial

    NARCIS (Netherlands)

    Knoop, J.; Steultjens, M.P.M.; Roorda, L.D.; Lems, W.F.; van der Esch, M.; Thorstensson, C.A.; Twisk, J.W.R.; Bierma-Zeinstra, S.M.A.; van der Leeden, M.; Dekker, J.

    2015-01-01

    Objectives: Although exercise therapy is effective for reducing pain and activity limitations in patients with knee osteoarthritis (OA), the underlying mechanisms are unclear. This study aimed to evaluate if improvements in neuromuscular factors (i.e. upper leg muscle strength and knee

  19. Contribution of Leg Muscle Explosive Power and Eye-Hand Coordination to The Accuracy Smash of Athletes in Volleyball Club of Universitas Islam Riau

    Directory of Open Access Journals (Sweden)

    Mimi Yulianti

    2017-11-01

    Full Text Available The purpose of this study was to determine the contribution of leg muscle explosive power and eye-hand coordination. The type of research was correlational. The population in this study was all athletes who actively follow the training as many as 20 people and using total sampling technique. Thus the sample in this study amounted to 20 men athletes. The data were collected using the measurement test on the three variables: the leg muscle explosive power data was using vertical jump test, eyehand coordination was using ballwerfen und fangen test and smash accuracy was using smash accuracy test. The data were analyzed by product moment correlation and double correlation and then continued with contribution of the determinant formula. Based on data analysis found that there was contribution of leg muscle explosive power equal to 35,52%, eye-hand coordination equal to 20,79%, and both equal to 40,70% regarding to the accuracy smash of volleyball atletes of Universitas Islam Riau. It was concluded that there was contribution of leg muscle explosive power and eye-hand coordination to the smash accuracy of volleyball athlete of Universitas Islam Riau.

  20. Leg for life? The use of sartorius muscle flap for the treatment of an infected vascular reconstructions after VA-ECMO use. A case report

    Directory of Open Access Journals (Sweden)

    George V. Patrut

    2015-01-01

    Conclusion: Although ischemic complications associated with VA-ECMO are accepted by intensivists under the slogan “leg for life”, for the repair of the femoral artery in the presence of groin infection the sartorius muscle remains an efficient solution for limb salvage.

  1. Bilateral idiopathic calf muscle hypertrophy: an exceptional cause of unsightly leg curvature.

    Science.gov (United States)

    Herlin, C; Chaput, B; Rivier, F; Doucet, J C; Bigorre, M; Captier, G

    2015-04-01

    The authors present the management of a young female patient who presented with longstanding bilateral calf muscle hypertrophy, with no known cause. Taking into account the patient's wishes and the fact that the hypertrophy was mainly located in the posteromedial compartment, we chose to carry out a subtotal bilateral resection of medial gastrocnemius muscles. This procedure was performed with an harmonic scalpel, permitting a excellent cosmetic result while avoiding complications or functional impairment. After a reviewing of the commonly used techniques, the authors discuss the chosen surgical approach taking into account its clinical particularity. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  2. Determining physiological cross-sectional area of extensor carpi radialis longus and brevis as a whole and by regions using 3D computer muscle models created from digitized fiber bundle data.

    Science.gov (United States)

    Ravichandiran, Kajeandra; Ravichandiran, Mayoorendra; Oliver, Michele L; Singh, Karan S; McKee, Nancy H; Agur, Anne M R

    2009-09-01

    Architectural parameters and physiological cross-sectional area (PCSA) are important determinants of muscle function. Extensor carpi radialis longus (ECRL) and brevis (ECRB) are used in muscle transfers; however, their regional architectural differences have not been investigated. The aim of this study is to develop computational algorithms to quantify and compare architectural parameters (fiber bundle length, pennation angle, and volume) and PCSA of ECRL and ECRB. Fiber bundles distributed throughout the volume of ECRL (75+/-20) and ECRB (110+/-30) were digitized in eight formalin embalmed cadaveric specimens. The digitized data was reconstructed in Autodesk Maya with computational algorithms implemented in Python. The mean PCSA and fiber bundle length were significantly different between ECRL and ECRB (p < or = 0.05). Superficial ECRL had significantly longer fiber bundle length than the deep region, whereas the PCSA of superficial ECRB was significantly larger than the deep region. The regional quantification of architectural parameters and PCSA provides a framework for the exploration of partial tendon transfers of ECRL and ECRB.

  3. Muscle activity during leg strengthening exercise using free weights and elastic resistance

    DEFF Research Database (Denmark)

    Jakobsen, Markus Due; Sundstrup, Emil; Andersen, Christoffer H

    2013-01-01

    ) activity was recorded in nine muscles during a standardized forward lunge movement performed with dumbbells and elastic bands during (1) ballistic vs. controlled exertion, and (2) at low, medium and high loads (33%, 66% and 100% of 10 RM, respectively). The recorded EMG signals were normalized to MVC EMG...

  4. Association between leg strength and muscle cross-sectional area of the quadriceps femoris with the physical activity level in octogenarians.

    Science.gov (United States)

    Latorre-Román, Pedro Á; Arévalo-Arévalo, Juan Manuel; García-Pinillos, Felipe

    2016-06-03

    Aging is a complex physiological process whose main feature is the progressive loss of functionality, which may be delayed or attenuated by improving physical fitness.  To determine the association between leg strength and the muscle cross-sectional area of the quadriceps femoris in relation to physical activity level in the elderly.  Thirty-two functionally autonomous people over 80 years (men: 82.80±2.09 years; women: 83.77±4.09 years) participated in this study. The Barthel Index, the Yale Physical Activity Survey and the Chair Stand Test were the instruments used.  There were significant differences between sexes in muscle area (pmen. The muscle area and the Chair Stand Test correlated significantly with the walk index (r=0.445, pactivity index (r=0.430, pactivity index, muscle area and the Chair Stand Test, only the latter behaved as a predictor variable.  Muscle strength and muscle mass of quadriceps showed a significant association with the physical activity level in older people. Leg muscle strength was useful to reveal muscle mass and physical activity level in older people, which is relevant as a clinical practice indicator.

  5. Phosphorylation potential in the dominant leg is lower, and [ADPfree] is higher in calf muscles at rest in endurance athletes than in sprinters and in untrained subjects.

    Science.gov (United States)

    Zoladz, J A; Kulinowski, P; Zapart-Bukowska, J; Grandys, M; Majerczak, J; Korzeniewski, B; Jasiński, A

    2007-12-01

    It has been reported that various types of mammalian muscle fibers differ regarding the content of several metabolites at rest. However, to our knowledge no data have been reported in the literature, concerning the muscle energetic status at rest in high class athletes when considering the dominant and non-dominant leg separately. We have hypothesised that due to higher mechanical loads on the dominant leg in athletes, the metabolic profile in the dominant leg at rest in the calf muscles, characterized by [PCr], [ADP(free)], [AMP(free)] and DeltaG(ATP), will significantly differ among endurance athletes, sprinters and untrained individuals. In this study we determined the DeltaG(ATP) and adenine phosphates concentrations in the dominant and non-dominant legs in untrained subjects (n = 6), sprinters (n = 10) and endurance athletes (n = 7) at rest. The (mean +/- SD) age of the subjects was 23.4 +/- 4.3 years. Muscle metabolites were measured in the calf muscles at rest, by means of (31)P-MRS, using a 4.7 T superconducting magnet (Bruker). When taking into account mean values in the left and right leg, phosphocreatine concentration ([PCr]) and DeltaG(ATP) were significantly lower (p<0.05, Wilcoxon-Mann-Whitney test), and [ADP(free)] was significantly higher (p = 0.04) in endurance athletes than in untrained subjects. When considering the differences between the left and right leg, [PCr] in the dominant leg was significantly lower in endurance athletes than in sprinters (p = 0.01) and untrained subjects (p = 0.02) (25.91 +/- 2.87 mM; 30.02 +/- 3.12 mM and 30.71 +/- 2.88 mM, respectively). The [ADP(free)] was significantly higher (p = 0.02) in endurance athletes than in sprinters and untrained subjects (p = 0.02) (42.19 +/- 13.44 microM; 27.86 +/- 10.19 microM; 25.35 +/- 10.97 microM, respectively). The DeltaG(ATP) in the dominant leg was significantly lower (p = 0.02) in endurance athletes than in sprinters and untrained subjects (p = 0.01) (-60.53 +/- 2.03 kJ.M(-1

  6. Muscle activity and spine load during anterior chain whole body linkage exercises: the body saw, hanging leg raise and walkout from a push-up.

    Science.gov (United States)

    McGill, Stuart; Andersen, Jordan; Cannon, Jordan

    2015-01-01

    This study examined anterior chain whole body linkage exercises, namely the body saw, hanging leg raise and walkout from a push-up. Investigation of these exercises focused on which particular muscles were challenged and the magnitude of the resulting spine load. Fourteen males performed the exercises while muscle activity, external force and 3D body segment motion were recorded. A sophisticated and anatomically detailed 3D model used muscle activity and body segment kinematics to estimate muscle force, and thus sensitivity to each individual's choice of motor control for each task. Gradations of muscle activity and spine load characteristics were observed across tasks. On average, the hanging straight leg raise created approximately 3000 N of spine compression while the body saw created less than 2500 N. The hanging straight leg raise created the highest challenge to the abdominal wall (>130% MVC in rectus abdominis, 88% MVC in external oblique). The body saw resulted in almost 140% MVC activation of the serratus anterior. All other exercises produced substantial abdominal challenge, although the body saw did so in the most spine conserving way. These findings, along with consideration of an individual's injury history, training goals and current fitness level, should assist in exercise choice and programme design.

  7. Age-related differences in the response of leg muscle cross-sectional area and water diffusivity measures to a period of supine rest.

    Science.gov (United States)

    Lorbergs, Amanda L; Noseworthy, Michael D; MacIntyre, Norma J

    2015-06-01

    The object was to assess whether cross-sectional area (CSA) and water diffusion properties of leg muscles in young and older women change with increased time spent in supine rest. Healthy young (n = 9, aged 20-30 years) and older (n = 9, aged 65-75 years) women underwent MRI scanning of the right leg at baseline, 30 and 60 min of supine rest. Muscle CSA was derived from proton density images. Water diffusion properties [apparent diffusion coefficient (ADC) and fractional anisotropy (FA)] of the tibialis anterior and posterior, soleus, and medial and lateral heads of the gastrocnemius were derived from diffusion tensor imaging (DTI). Repeated measures ANOVAs and Bonferroni post hoc tests determined the effects of time and group on each muscle outcome. In both groups, muscle CSA and FA did not significantly change over time, whereas ADC significantly decreased. A greater decline at 30 min for young women was only observed for ADC in the medial gastrocnemius. Regardless of age, ADC values decreased with fluid shift associated with time spent supine, whereas CSA and FA were not affected. For leg muscle assessment in young and older women, DTI scanning protocols should consider the amount of time spent in a recumbent position.

  8. Childhood development of common drive to a human leg muscle during ankle dorsiflexion and gait

    DEFF Research Database (Denmark)

    Hvass Petersen, Tue; Kliim-Due, Mette; Farmer, Simon F.

    2010-01-01

    static ankle dorsiflexion. A significant correlation with age was also found in the 15-25 Hz frequency band (beta) during static foot dorsiflexion. Chi2 analysis of differences of coherence between different age groups of children (4-6, 7-9, 10-12, and 13-15 yrs of age) revealed a significant lower...... to precisely control the ankle joint position with age, which may be contingent on maturation of corticospinal control of the foot dorsiflexor muscles....

  9. 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...

  10. Intermittent pneumatic leg compressions enhance muscle performance and blood flow in a model of peripheral arterial insufficiency.

    Science.gov (United States)

    Roseguini, Bruno T; Arce-Esquivel, Arturo A; Newcomer, Sean C; Yang, Hsiao T; Terjung, Ronald; Laughlin, M H

    2012-05-01

    Despite the escalating prevalence in the aging population, few therapeutic options exist to treat patients with peripheral arterial disease. Application of intermittent pneumatic leg compressions (IPC) is regarded as a promising noninvasive approach to treat this condition, but the clinical efficacy, as well the mechanistic basis of action of this therapy, remain poorly defined. We tested the hypothesis that 2 wk of daily application of IPC enhances exercise tolerance by improving blood flow and promoting angiogenesis in skeletal muscle in a model of peripheral arterial insufficiency. Male Sprague-Dawley rats were subjected to bilateral ligation of the femoral artery and randomly allocated to treatment or sham groups. Animals were anesthetized daily and exposed to 1-h sessions of bilateral IPC or sham treatment for 14-16 consecutive days. A third group of nonligated rats was also studied. Marked increases in treadmill exercise tolerance (∼33%, P < 0.05) and improved muscle performance in situ (∼10%, P < 0.05) were observed in IPC-treated animals. Compared with sham-treated controls, blood flow measured with isotope-labeled microspheres during in situ contractions tended to be higher in IPC-treated animals in muscles composed of predominantly fast-twitch white fibers, such as the plantaris (∼93%, P = 0.02). Capillary contacts per fiber and citrate synthase activity were not significantly altered by IPC treatment. Collectively, these data indicate that IPC improves exercise tolerance in a model of peripheral arterial insufficiency in part by enhancing blood flow to collateral-dependent tissues.

  11. Activation timing of postural muscles of lower legs and prediction of postural disturbance during bilateral arm flexion in older adults.

    Science.gov (United States)

    Yaguchi, Chie; Fujiwara, Katsuo; Kiyota, Naoe

    2017-12-22

    Activation timings of postural muscles of lower legs and prediction of postural disturbance were investigated in young and older adults during bilateral arm flexion in a self-timing task and an oddball task with different probabilities of target presentation. Arm flexion was started from a standing posture with hands suspended 10 cm below the horizontal level in front of the body, in which postural control focused on the ankles is important. Fourteen young and 14 older adults raised the arms in response to the target sound signal. Three task conditions were used: 15 and 45% probabilities of the target in the oddball task and self-timing. Analysis items were activation timing of postural muscles (erector spinae, biceps femoris, and gastrocnemius) with respect to the anterior deltoid (AD), and latency and amplitude of the P300 component of event-related brain potential. For young adults, all postural muscles were activated significantly earlier than AD under each condition, and time of preceding gastrocnemius activation was significantly longer in the order of the self-timing, 45 and 15% conditions. P300 latency was significantly shorter, and P300 amplitude was significantly smaller under the 45% condition than under the 15% condition. For older adults, although all postural muscles, including gastrocnemius, were activated significantly earlier than AD in the self-timing condition, only activation timing of gastrocnemius was not significantly earlier than that of AD in oddball tasks, regardless of target probability. No significant differences were found between 15 and 45% conditions in onset times of all postural muscles, and latency and amplitude of P300. These results suggest that during arm movement, young adults can achieve sufficient postural preparation in proportion to the probability of target presentation in the oddball task. Older adults can achieve postural control using ankle joints in the self-timing task. However, in the oddball task, older adults

  12. Effects of short-term isokinetic training with reciprocal knee extensors agonist and antagonist muscle actions : A controlled and randomized trial

    NARCIS (Netherlands)

    Cunha, Rafael; Carregaro, Rodrigo L.; Martorelli, André; Vieira, Amilton; Oliveira, Ana B.; Bottaro, Martim

    Background: Previous studies have shown that preloading an antagonist muscle may increase the acute agonist neuromuscular performance. In addition, studies have suggested that very short-term resistance exercise (RE) programs may also be useful to increase strength and muscular performance.

  13. Complex Anatomic Abnormalities of the Lower Leg Muscles and Tendons Associated With Phocomelia: A Case Report.

    Science.gov (United States)

    Hodo, Thomas; Hamrick, Mark; Melenevsky, Yulia

    Musculoskeletal anatomy is widely known to have components that stray from the norm in the form of variant muscle and tendon presence, absence, origin, insertion, and bifurcation. Although these variant muscles and tendons might be deemed incidental and insignificant findings by most, they can be important contributors to pathologic physiology or, more importantly, an option for effective treatment. In the present case report, we describe a patient with phocomelia and Müllerian abnormalities secondary to in utero thalidomide exposure. The patient had experienced recurrent bilateral foot pain accompanied by numbness, stiffness, swelling, and longstanding pes planus. These symptoms persisted despite conservative treatment with orthotics, steroids, and nonsteroidal anti-inflammatory drugs. Radiographic imaging showed dysmorphic and degenerative changes of the ankle and foot joints. Further investigation with magnetic resonance imaging revealed complex anatomic abnormalities, including the absence of the posterior tibialis and peroneus brevis, lateralization of the peroneus longus, and the presence of a variant anterior compartment muscle. The variant structure was likely a previously described anterior compartment variant, anterior fibulocalcaneus, and might have been a source of the recurrent pain. Also, the absence of the posterior tibialis might have caused the pes planus in the present patient, considering that posterior tibialis tendon dysfunction is the most common cause of acquired pes planus. Although thalidomide infrequently affects the lower extremities, its effects on growth and development were likely the cause of this rare array of anatomic abnormalities and resulting ankle and foot pathologic features. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Does peroperative external pneumatic leg muscle compression prevent post-operative venous thrombosis in neurosurgery?

    Science.gov (United States)

    Bynke, O; Hillman, J; Lassvik, C

    1987-01-01

    Post-operative deep venous thrombosis (DVT) is a frequent and potentially life-threatening complication in neurosurgery. In this field of surgery, with its special demands for exact haemostasis, prophylaxis against deep venous thrombosis with anticoagulant drugs has been utilized only reluctantly. Postoperative pneumatic muscle compression (EPC) has been shown to be effective, although there are several practical considerations involved with this method which limit its clinical applicability. In the present study per-operative EPC was evaluated and was found to provide good protection against DVT in patients with increased risk from this complication. This method has the advantage of being effective, safe, inexpensive and readily practicable.

  15. Effect of Feedback Corrective Exercise on Knee Valgus and Electromyographic Activity of Lower Limb Muscles in Single Leg Squat

    Directory of Open Access Journals (Sweden)

    Negar Koorosh-fard

    2015-07-01

    Full Text Available Objective: The aim of this study was assessing the effect of feedback correcting exercise in front of mirror during running on frontal plane knee and pelvic kinematic and electromyography activity of some lower extremity muscles in single leg squat (SLS. Materials & Methods: This study was quasi experimental. 23 active female subjects participated in two experimental and control groups with mean age (21.86± 2.43 years .experimental group contains subjects with knee valgus and pelvic drop angle more than a mean plus one standard deviation of the population in functional SLS. Muscular activity (RMS of gluteus maximus, Gluteus medius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus, angle of knee valgus and pelvic drop were register in end of SLS Pre and post of 8 training sessions. Comparing Variable has done with independent t statistical test between 2 groups and pair sample t test within each groups with significant level of 0.05. Results: Statistical analysis Before training showed no significant differences in pelvic drop between two groups (P&ge0.05, but knee valgus angle was significantly more than control group (P&le0.05. In spit that most muscle activities (% MVC except biceps femoris (P&le0.05, were greater in experimental group, no significant difference (P&ge0.05 has seen in two groups. Comparing pre and post test has showed no significant difference in knee valgus of experimental group, however it decreased around 2 degrees and although %MVC decreased in all muscles, just rectuse femoris has shown significant difference (P&le0.05. No significant difference has seen in control group in all variables (P&ge0.05. Conclusion: Findings showed poor neuromuscular control in experimental group which improved to some extent after training because lower muscle activity and energy consumption in specific movement with similar kinematic indicate improvement of motor control or cause learning. It seems that

  16. Improvement in upper leg muscle strength underlies beneficial effects of exercise therapy in knee osteoarthritis: secondary analysis from a randomised controlled trial.

    Science.gov (United States)

    Knoop, J; Steultjens, M P M; Roorda, L D; Lems, W F; van der Esch, M; Thorstensson, C A; Twisk, J W R; Bierma-Zeinstra, S M A; van der Leeden, M; Dekker, J

    2015-06-01

    Although exercise therapy is effective for reducing pain and activity limitations in patients with knee osteoarthritis (OA), the underlying mechanisms are unclear. This study aimed to evaluate if improvements in neuromuscular factors (i.e. upper leg muscle strength and knee proprioception) underlie the beneficial effects of exercise therapy in patients with knee OA. Secondary analyses from a randomised controlled trial, with measurements at baseline, 6 weeks, 12 weeks and 38 weeks. Rehabilitation centre. One hundred and fifty-nine patients diagnosed with knee OA. Exercise therapy. Changes in pain [numeric rating scale (NRS)] and activity limitations [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale and get-up-and-go test] during the study period. Independent variables were changes in upper leg muscle strength and knee joint proprioception (i.e. motion sense) during the study period. Longitudinal regression analyses (generalised estimating equation) were performed to analyse associations between changes in upper leg muscle strength and knee proprioception with changes in pain and activity limitations. Improved muscle strength was significantly associated with reductions in NRS pain {B coefficient -2.5 [95% confidence interval (CI) -3.7 to -1.4], meaning that every change of 1 unit of strength was linked to a change of -2.5 units of pain}, WOMAC physical function (-8.8, 95% CI -13.4 to -4.2) and get-up-and-go test (-1.7, 95% CI -2.4 to -1.0). Improved proprioception was not significantly associated with better outcomes of exercise therapy (P>0.05). Upper leg muscle strengthening is one of the mechanisms underlying the beneficial effects of exercise therapy in patients with knee OA. Copyright © 2014 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

  17. T₂ mapping provides multiple approaches for the characterization of muscle involvement in neuromuscular diseases: a cross-sectional study of lower leg muscles in 5-15-year-old boys with Duchenne muscular dystrophy.

    Science.gov (United States)

    Arpan, Ishu; Forbes, Sean C; Lott, Donovan J; Senesac, Claudia R; Daniels, Michael J; Triplett, William T; Deol, Jasjit K; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

    2013-03-01

    Skeletal muscles of children with Duchenne muscular dystrophy (DMD) show enhanced susceptibility to damage and progressive lipid infiltration, which contribute to an increase in the MR proton transverse relaxation time (T₂). Therefore, the examination of T₂ changes in individual muscles may be useful for the monitoring of disease progression in DMD. In this study, we used the mean T₂, percentage of elevated pixels and T₂ heterogeneity to assess changes in the composition of dystrophic muscles. In addition, we used fat saturation to distinguish T₂ changes caused by edema and inflammation from fat infiltration in muscles. Thirty subjects with DMD and 15 age-matched controls underwent T₂ -weighted imaging of their lower leg using a 3-T MR system. T₂ maps were developed and four lower leg muscles were manually traced (soleus, medial gastrocnemius, peroneal and tibialis anterior). The mean T₂ of the traced regions of interest, width of the T₂ histograms and percentage of elevated pixels were calculated. We found that, even in young children with DMD, lower leg muscles showed elevated mean T₂, were more heterogeneous and had a greater percentage of elevated pixels than in controls. T₂ measures decreased with fat saturation, but were still higher (P muscles than in controls. Further, T₂ measures showed positive correlations with timed functional tests (r = 0.23-0.79). The elevated T₂ measures with and without fat saturation at all ages of DMD examined (5-15 years) compared with unaffected controls indicate that the dystrophic muscles have increased regions of damage, edema and fat infiltration. This study shows that T₂ mapping provides multiple approaches that can be used effectively to characterize muscle tissue in children with DMD, even in the early stages of the disease. Therefore, T₂ mapping may prove to be clinically useful in the monitoring of muscle changes caused by the disease process or by therapeutic interventions in DMD

  18. Chronic impairment of leg muscle blood flow following cardiac catheterization in childhood

    International Nuclear Information System (INIS)

    Skovranek, J.; Samanek, M.

    1979-01-01

    In 99 patients with congenital heart defects or chronic respiratory disease without clinical symptoms of disturbances in peripheral circulation, resting and maximal blood flow in the anterior tibial muscle of both extremities were investigated 2.7 yrs (average) after cardiac catheterization. The method used involved 133 Xe clearance. Resting blood flow was normal and no difference could be demonstrated between the extremity originally used for catheterization and the contralateral control extremity. No disturbance in maximal blood flow could be proved in the extremity used for catheterization by the venous route only. Maximal blood flow was significantly lower in that extremity where the femoral artery had been catheterized or cannulated for pressure measurement and blood sampling. The disturbance in maximal flow was shown regardless of whether the arterial catheterization involved the Seldinger percutaneous technique, arteriotomy, or mere cannulation of the femoral artery. The values in the involved extremity did not differ significantly from the values in a healthy population

  19. Anatomical aspects of the nerves of the leg and foot of the giant anteater (Myrmecophaga tridactyla, Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    V.S. Cruz

    2014-10-01

    Full Text Available Although distal stifle joint nerve distribution has been well established in domestic animals, this approach is scarcely reported in wild animals. Therefore, the aim of this study was to describe the nerves of the leg and foot of Myrmecophaga tridactyla with emphasis on their ramification, distribution, topography and territory of innervation. For this purpose, six adult cadavers fixed and preserved in 10% formalin solution were used. The nerves of the leg and foot of the M. tridactyla were the saphenous nerve (femoral nerve branch, fibular and tibial nerves and lateral sural cutaneous nerve (branches of the sciatic nerve and caudal sural cutaneous nerve (tibial nerve branch. The saphenous nerve branches to the skin, the craniomedial surface of the leg, the medial surface of the tarsal and metatarsal regions and the dorsomedial surface of the digits I and II (100% of cases, III (50% of cases and IV (25% of cases. The lateral sural cutaneous nerve innervates the skin of the craniolateral region of the knee and leg. The fibular nerve innervates the flexor and extensor muscles of the tarsal region of the digits and skin of the craniolateral surface of the leg and dorsolateral surface of the foot. The tibial nerve innervates the extensor muscles of the tarsal joint and flexor, adductor and abductor muscles of the digits and the skin of the plantar surface. The caudal sural cutaneous nerve innervates the skin of the caudal surface of the leg. The nerves responsible for the leg and foot innervation were the same as reported in domestic and wild animals, but with some differences, such as the more distal division of the common fibular nerve, the absence of dorsal metatarsal branches of the deep fibular nerve and a greater involvement of the saphenous nerve in the digital innervation with branches to the digits III and IV, in addition to digits I and II.

  20. Acute impact of intermittent pneumatic leg compression frequency on limb hemodynamics, vascular function, and skeletal muscle gene expression in humans.

    Science.gov (United States)

    Sheldon, Ryan D; Roseguini, Bruno T; Thyfault, John P; Crist, Brett D; Laughlin, M H; Newcomer, Sean C

    2012-06-01

    The mechanisms by which intermittent pneumatic leg compression (IPC) treatment effectively treats symptoms associated with peripheral artery disease remain speculative. With the aim of gaining mechanistic insight into IPC treatment, the purpose of this study was to investigate the effect of IPC frequency on limb hemodynamics, vascular function, and skeletal muscle gene expression. In this two study investigation, healthy male subjects underwent an hour of either high-frequency (HF; 2-s inflation/3-s deflation) or low-frequency (LF; 4-s inflation/16-s deflation) IPC treatment of the foot and calf. In study 1 (n = 11; 23.5 ± 4.7 yr), subjects underwent both HF and LF treatment on separate days. Doppler/ultrasonography was used to measure popliteal artery diameter and blood velocity at baseline and during IPC treatment. Flow-mediated dilation (FMD) and peak reactive hyperemia blood flow (RHBF) were determined before and after IPC treatment. In study 2 (n = 19; 22.0 ± 4.6 yr), skeletal muscle biopsies were taken from the lateral gastrocnemius of the treated and control limb at baseline and at 30- and 150-min posttreatment. Quantitative PCR was used to assess mRNA concentrations of genes associated with inflammation and vascular remodeling. No treatment effect on vascular function was observed. Cuff deflation resulted in increased blood flow (BF) and shear rate (SR) in both treatments at the onset of treatment compared with baseline (P < 0.01). BF and SR significantly diminished by 45 min of HF treatment only (P < 0.01). Both treatments reduced BF and SR and elevated oscillatory shear index compared with baseline (P < 0.01) during cuff inflation. IPC decreased the mRNA expression of cysteine-rich protein 61 from baseline and controls (P <0 .01) and connective tissue growth factor from baseline (P < 0.05) in a frequency-dependent manner. In conclusion, a single session of IPC acutely impacts limb hemodynamics and skeletal muscle gene expression in a frequency

  1. 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.

  2. Passive leg movement enhances interstitial VEGF protein, endothelial cell proliferation, and eNOS mRNA content in human skeletal muscle

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Rufener, Nora; Nielsen, Jens J

    2008-01-01

    .05) in blood flow without a significant enhancement in oxygen uptake. Muscle interstitial fluid was sampled with microdialysis technique and analyzed for vascular endothelial growth factor (VEGF) protein and for the effect on endothelial cell proliferation. Biopsies obtained from the musculus vastus lateralis...... to cultured endothelial cells revealed that dialysate obtained during leg movement induced a 3.2-fold higher proliferation rate (P level fourfold above resting levels. VEGF mRNA and MMP-2 mRNA levels were...

  3. Clinical Significance of Presence of Extensor Indicis Brevis Manus – A Case Report

    Directory of Open Access Journals (Sweden)

    N Esakkiammal

    2017-11-01

    Full Text Available Anatomical variations of additional muscles and tendons are commonly encountered in extensor aspect of forearm and hand during surgeries and dissections. There are reports on different kinds of variations like, extra tendons, additional bellies, and abnormal attachments of the muscle. Surgeons should have the knowledge about these variations for muscle or tendon grafting and also to plan surgeries. While dissecting the extensor compartment forearm and dorsum of hand of an elderly female cadaver, an anomalous muscle belly was noticed on dorsum of hand bilaterally alongwith the main tendon of extensor indicis muscle. This additional belly of extensor indicis muscle was called Extensor Indicis Brevis Manus (EIBM. This muscle originated from the dorsal carpal ligament and joined the main tendon of extensor indicis muscle in both the hands. Awareness of existence of this kind of variation is important for clinicians and surgeons for a correct diagnosis and eventual surgery in patients presenting with a cyst on the dorsum of hand, to avoid accidental mishaps.

  4. Low blood flow at onset of moderate-intensity exercise does not limit muscle oxygen uptake

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan P; Saltin, Bengt

    2010-01-01

    The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 +/- 1 W, mean +/- SD) without (Con) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (N(G)-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25-50% lower (P ... +/- 12 vs. 262 +/- 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset...

  5. AMP kinase expression and activity in human skeletal muscle: effects of immobilization, retraining, and creatine supplementation

    DEFF Research Database (Denmark)

    Eijnde, Bert O.; Derave, Wim; Wojtaszewski, Jørgen

    2005-01-01

    The effects of leg immobilization and retraining in combination with oral creatine intake on muscle AMP-activated protein kinase (AMPK) protein expression and phosphorylation status were investigated. A double-blind trial was performed in young healthy volunteers (n = 22). A cast immobilized...... the right leg for 2 wk, whereafter the knee-extensor muscles of that leg were retrained for 6 wk. Half of the subjects received creatine monohydrate throughout the study (Cr; from 15 g down to 2.5 g daily), and the others ingested placebo (P; maltodextrin). Before and after immobilization and retraining...... that immobilization-induced muscle inactivity for 2 wk does not alter AMPK a1-, a2-, and ß2-subunit expression or a-AMPK phosphorylation status. Furthermore, the present observations indicate that AMPK probably is not implicated in the previously reported beneficial effects of oral creatine supplementation on muscle...

  6. On the relationship between lower extremity muscles activation and peak vertical and posterior ground reaction forces during single leg drop landing.

    Science.gov (United States)

    Mahaki, M; Mi'mar, R; Mahaki, B

    2015-10-01

    Anterior cruciate ligament (ACL) injury continues to be an important medical issue for athletes participating in sports. Vertical and posterior ground reaction forces have received considerable attention for their potential influence on ACL injuries. The purpose of this study was to examine the relationship between electromyographic activity of lower extremity muscles and the peak vertical and posterior ground reaction forces during single leg drop landing. Thirteen physical education male students participated in this correlation study. Electromyographic activities of gluteus medius, biceps femoris, medial gastrocnemius, soleus as well as anterior tibialis muscles along with ground reaction forces were measured. Participants performed single-leg landing from a 0.3 m height on to a force platform. Landing was divided into two phases: 100 ms preceding ground contact and 100 ms proceeding ground contact. Pearson correlation test was used to determine the relationships between these muscles activity and peak vertical and posterior ground reaction forces. The results of the study indicated that the activity of soleus and tibialis anterior in pre-landing phase were positively correlated with peak vertical ground reaction force ([P≤0.04], [P≤0.008], respectively). However, no significant correlation was found between the activities of other muscles in pre-landing phase and peak vertical as well as peak posterior ground reaction forces. Also, no significant correlation was found between the activities of muscles in post-landing phase and peak vertical as well as peak posterior ground reaction forces. Soleus loading shifts the proximal tibia posterior at the knee joint and tibialis anterior prevent hyperporonation of the ankle, a mechanisms of ACL injury. Hence, neuromuscular training promoting preparatory muscle activity in these muscles may reduce the incidence of ACL injuries.

  7. [Absolute and relative strength-endurance of the knee flexor and extensor muscles: a reliability study using the IsoMed 2000-dynamometer].

    Science.gov (United States)

    Dirnberger, J; Wiesinger, H P; Stöggl, T; Kösters, A; Müller, E

    2012-09-01

    Isokinetic devices are highly rated in strength-related performance diagnosis. A few years ago, the broad variety of existing products was extended by the IsoMed 2000-dynamometer. In order for an isokinetic device to be clinically useful, the reliability of specific applications must be established. Although there have already been single studies on this topic for the IsoMed 2000 concerning maximum strength measurements, there has been no study regarding the assessment of strength-endurance so far. The aim of the present study was to establish the reliability for various methods of quantification of strength-endurance using the IsoMed 2000. A sample of 33 healthy young subjects (age: 23.8 ± 2.6 years) participated in one familiarisation and two testing sessions, 3-4 days apart. Testing consisted of a series 30 full effort concentric extension-flexion cycles of the right knee muscles at an angular velocity of 180 °/s. Based on the parameters Peak, Torque and Work for each repetition, indices of absolute (KADabs) and relative (KADrel) strength-endurance were derived. KADabs was calculated as the mean value of all testing repetitions, KADrel was determined in two ways: on the one hand, as the percentage decrease between the first and the last 5 repetitions (KADrelA) and on the other, as the negative slope derived from the linear regression equitation of all repetitions (KADrelB). Detection of systematic errors was performed using paired sample t-tests, relative and absolute reliability were examined using intraclass correlation coefficient (ICC 2.1) and standard error of measurement (SEM%), respectively. In general, for extension measurements concerning KADabs and - in an weakened form - KADrel high ICC -values of 0.76-0.89 combined with clinically acceptable values of SEM% of 1.2-5.9 % could be found. For flexion measurements this only applies to KADabs, whereas results for KADrel turned out to be clearly weaker with ICC- and SEM% values of 0.42-0.62 and 9

  8. Effect of Body Mass Index on Postural Balance and Muscle Strength in Children Aged 8-10 years

    Directory of Open Access Journals (Sweden)

    Lucky Prasetiowati

    2017-04-01

    Full Text Available Background:Childhood overweight and obesity, which are considered as global epidemic, can be assessed using Body Mass Index (BMI. BMI difference can lead to anatomic changes due to an increased body load. This increase might also affect motor performance, including changes in postural balance and muscle strength. Aims and Objectives: to explain the influence of BMI on postural balance and lower limb muscle strength and to assess the correlation between those two variables in children aged 8-10 years. Material and methods:The sample consisted of 63 children aged 8-10 years, which were divided in 3 groups: BMI-normal, BMI-overweight, and BMI-obese. The postural balance was assessed using single leg balance test on MatScan and the Center Of Pressure (COP area was recorded. Isometric muscle strength of hip extensor and knee extensor were measured using a hand-held dynamometer. Results: Obese children had significantly largerCOP area than overweight (p = 0.004 and normal weight children (p = 0.000.There were no significant differences in hip extensor muscle strength between obese children with overweight and normal weight children (p=0.527. The absolute knee extensor muscle strength in obese group was significantly higher than the overweight and normal group (p = 0.003. However the relative muscle strength of lower limb for obese children was significantly lower than for normal weight. There was no significant correlation between absolute hip extensor and knee extensor muscles strength with COP area. Conclusion: Obese children have decreased postural balance and increased absolute knee extensormuscle strength significantly when compared to overweight and normal children. There is no significant correlation between postural balance and muscle strength.

  9. Interleukin-6 production in contracting human skeletal muscle is influenced by pre-exercise muscle glycogen content

    DEFF Research Database (Denmark)

    Steensberg, A; Febbraio, M A; Osada, T

    2001-01-01

    1. Prolonged exercise results in a progressive decline in glycogen content and a concomitant increase in the release of the cytokine interleukin-6 (IL-6) from contracting muscle. This study tests the hypothesis that the exercise-induced IL-6 release from contracting muscle is linked to the intram......1. Prolonged exercise results in a progressive decline in glycogen content and a concomitant increase in the release of the cytokine interleukin-6 (IL-6) from contracting muscle. This study tests the hypothesis that the exercise-induced IL-6 release from contracting muscle is linked...... to the intramuscular glycogen availability. 2. Seven men performed 5 h of a two-legged knee-extensor exercise, with one leg with normal, and one leg with reduced, muscle glycogen content. Muscle biopsies were obtained before (pre-ex), immediately after (end-ex) and 3 h into recovery (3 h rec) from exercise in both...... legs. In addition, catheters were placed in one femoral artery and both femoral veins and blood was sampled from these catheters prior to exercise and at 1 h intervals during exercise and into recovery. 3. Pre-exercise glycogen content was lower in the glycogen-depleted leg compared with the control...

  10. Effects of short-term isokinetic training with reciprocal knee extensors agonist and antagonist muscle actions: A controlled and randomized trial

    Directory of Open Access Journals (Sweden)

    Rafael Cunha

    2013-04-01

    Full Text Available BACKGROUND: Previous studies have shown that preloading an antagonist muscle may increase the acute agonist neuromuscular performance. In addition, studies have suggested that very short-term resistance exercise (RE programs may also be useful to increase strength and muscular performance. OBJECTIVES: To evaluate the effects of three days of RE using a reciprocal action method on the muscular performance of healthy men and to compare these effects with those of a traditional RE group. METHOD: Thirty-three men (21.1 ± 2.3 years were randomly assigned to one of three groups: 1 reciprocal (REC; knee flexion immediately followed by a knee extension exercise; 2 traditional (TRA; non-preload; a concentric knee extension exercise; and 3 control (CON; no exercise. The REC and TRA subjects performed four sets of 10 repetitions at 60º/s with one minute of rest. The pre- and post-RE tests included two sets of four maximal concentric repetitions at 60º/s and 180º/s. A 3x2 ANOVA with Tukey post-hoc was used to analyze the differences in peak torque (PT, rating of acceleration development (RAD and time to peak torque (TIMEtorque. RESULTS: A significant PT increase was found for REC and TRA (p CONTEXTUALIZAÇÃO: Estudos demonstraram que a pré-ativação de músculos antagonistas pode aumentar o desempenho neuromuscular agonista. Além disso, estudos sugerem que programas de exercício resistido (ER de curta duração podem ser úteis para aumentar a força muscular e o desempenho. OBJETIVOS: Avaliar os efeitos de três sessões de ER por meio do método de ações recíprocas no desempenho muscular de homens sadios e comparar com um grupo de ER tradicional. MÉTODO: Trinta e três homens (21,1 ± 2,3 anos foram randomicamente alocados em três grupos: Recíproco (REC: uma repetição de flexão do joelho imediatamente seguida por uma de extensão do joelho; Tradicional (TRA: exercício concêntrico de extensão do joelho e Controle (CON: não realizaram

  11. Selective contribution of each hamstring muscle to anterior cruciate ligament protection and tibiofemoral joint stability in leg-extension exercise: a simulation study.

    Science.gov (United States)

    Biscarini, Andrea; Botti, Fabio Massimo; Pettorossi, Vito Enrico

    2013-09-01

    A biomechanical model was developed to simulate the selective effect of the co-contraction force provided by each hamstring muscle on the shear and compressive tibiofemoral joint reaction forces, during open kinetic-chain knee-extension exercises. This model accounts for instantaneous values of knee flexion angle [Formula: see text], angular velocity and acceleration, and for changes in magnitude, orientation, and application point of external resistance. The tibiofemoral shear force (TFSF) largely determines the tensile force on anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). Biceps femoris is the most effective hamstring muscle in decreasing the ACL-loading TFSF developed by quadriceps contractions for [Formula: see text]. In this range, the semimembranosus generates the dominant tibiofemoral compressive force, which enhances joint stability, opposes anterior/posterior tibial translations, and protects cruciate ligaments. The semitendinosus force provides the greatest decreasing gradient of ACL-loading TFSF for [Formula: see text], and the greatest increasing gradient of tibiofemoral compressive force for [Formula: see text]. However, semitendinosus efficacy is strongly limited by its small physiological section. Hamstring muscles behave as a unique muscle in enhancing the PCL-loading TFSF produced by quadriceps contractions for [Formula: see text]. The levels of hamstrings co-activation that suppress the ACL-loading TFSF considerably shift when the knee angular acceleration is changed while maintaining the same level of knee extensor torque by a concurrent adjustment in the magnitude of external resistance. The knowledge of the specific role and the optimal activation level of each hamstring muscle in ACL protection and tibiofemoral stability are fundamental for planning safe and effective rehabilitative knee-extension exercises.

  12. Voluntary enhanced cocontraction of hamstring muscles during open kinetic chain leg extension exercise: its potential unloading effect on the anterior cruciate ligament.

    Science.gov (United States)

    Biscarini, Andrea; Benvenuti, Paolo; Botti, Fabio M; Brunetti, Antonella; Brunetti, Orazio; Pettorossi, Vito E

    2014-09-01

    A number of research studies provide evidence that hamstring cocontraction during open kinetic chain knee extension exercises enhances tibiofemoral (TF) stability and reduces the strain on the anterior cruciate ligament. To determine the possible increase in hamstring muscle coactivation caused by a voluntary cocontraction effort during open kinetic chain leg-extension exercises, and to assess whether an intentional hamstring cocontraction can completely suppress the anterior TF shear force during these exercises. Descriptive laboratory study. Knee kinematics as well as electromyographic activity in the semitendinosus (ST), semimembranosus (SM), biceps femoris (BF), and quadriceps femoris muscles were measured in 20 healthy men during isotonic leg extension exercises with resistance (R) ranging from 10% to 80% of the 1-repetition maximum (1RM). The same exercises were also performed while the participants attempted to enhance hamstring coactivation through a voluntary cocontraction effort. The data served as input parameters for a model to calculate the shear and compressive TF forces in leg extension exercises for any set of coactivation patterns of the different hamstring muscles. For R≤ 40% 1RM, the peak coactivation levels obtained with intentional cocontraction (l) were significantly higher (P hamstring muscle, maximum level l was reached at R = 30% 1RM, corresponding to 9.2%, 10.5%, and 24.5% maximum voluntary isometric contraction (MVIC) for the BF, ST, and SM, respectively, whereas the ratio l/l 0 reached its maximum at R = 20% 1RM and was approximately 2, 3, and 4 for the BF, SM, and ST, respectively. The voluntary enhanced coactivation level l obtained for R≤ 30% 1RM completely suppressed the anterior TF shear force developed by the quadriceps during the exercise. In leg extension exercises with resistance R≤ 40% 1RM, coactivation of the BF, SM, and ST can be significantly enhanced (up to 2, 3, and 4 times, respectively) by a voluntary hamstring

  13. Gender differences in rotation of the shank during single-legged drop landing and its relation to rotational muscle strength of the knee.

    Science.gov (United States)

    Kiriyama, Shinya; Sato, Haruhiko; Takahira, Naonobu

    2009-01-01

    Increased shank rotation during landing has been considered to be one of the factors for noncontact anterior cruciate ligament injuries in female athletes. There have been no known gender differences in rotational knee muscle strength, which is expected to inhibit exaggerated shank rotation. Women have less knee external rotator strength than do men. Lower external rotator strength is associated with increased internal shank rotation at the time of landing. Controlled laboratory study. One hundred sixty-nine healthy young subjects (81 female and 88 male; age, 17.0 +/- 1.0 years) volunteered to participate in this study. The subjects performed single-legged drop landings from a 20-cm height. Femoral and shank kinematics were measured using a 3D optoelectronic tracking system during the drop landings, and then the joint angles around the knee (flexion/extension, valgus/varus, and internal/external rotation) were calculated. The maximal isometric rotational muscle strength of the knee was measured at 30 degrees of knee flexion in a supine position using a dynamometer. The female subjects had significantly less external shank rotation strength than did the male subjects (P external rotation strength and the peak shank internal rotation angle during landing (r = -0.322, P external rotator strength. This may lead to large shank internal rotation movement during the single-legged drop landing. Improving strength training of the external rotator muscle may help decrease the rates of anterior cruciate ligament injury in female athletes.

  14. The influence of foot arch on ankle joint torques andon sEMG signal amplitude in selected lower leg muscles

    Directory of Open Access Journals (Sweden)

    Żebrowska Kinga

    2016-09-01

    Full Text Available Introduction: This study sought to assess the influence of proper foot arch on electromyographic activity of selected lower limb muscles. The aim of this work was to evaluate the effects of foot arch on the activity of selected muscles and to determine whether electromyography might help to identify types of flat feet resulting from muscle- or ligament-related causes.

  15. 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.

  16. 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.

  17. Muscle Cramps

    Science.gov (United States)

    ... Talk to your provider about the risks and benefits of medicines. How can I prevent muscle cramps? To prevent muscle cramps, you can Stretch your muscles, especially before exercising. If you often get leg cramps at night, ...

  18. Technetium-99m sestamibi leg scintigraphy for non-invasive assessment of propionyl-l-carnitine induced changes in skeletal muscle metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Cittanti, C. [Department of Nuclear Medicine, University of Ferrara (Italy); Colamussi, P. [Department of Nuclear Medicine, University of Ferrara (Italy); Giganti, M. [Department of Nuclear Medicine, University of Ferrara (Italy); Orlandi, C. [MEDCO Research, Inc., North Carolina (United States); Uccelli, L. [Department of Nuclear Medicine, University of Ferrara (Italy); Manfrini, S. [Surgical Pathology Institute, University of Ferrara (Italy); Azzena, G. [Surgical Pathology Institute, University of Ferrara (Italy); Piffanelli, A. [Department of Nuclear Medicine, University of Ferrara (Italy)

    1997-07-01

    Carnitine derivatives, such as propionyl-l-carnitine (PLC), have been shown to improve walking distance in patients with obstructive peripheral artery disease (PAOD). The aim of this study was to ascertain whether technetium-99m sestamibi leg scintigraphy may be a useful tool in the evaluation of changes in skeletal muscle metabolism induced by chronic therapy with PLC. Twenty patients with clinical and instrumental evidence of PAOD were randomly assigned to a 3-month period of therapy with either PLC or placebo. Rest {sup 99m}Tc-sestamibi leg scintigraphy and echo-Doppler sonography were performed on all subjects immediately before and upon completion of the treatment period. At the end of the protocol the following results were observed in patients who underwent PLC administration: (a) a significant increase in both thigh and calf {sup 99m}Tc-sestamibi uptake, in comparison with baseline values (P<0.001); (b) the absence of statistically significant modifications of Doppler blood flow indices of the lower limbs. In conclusion, after chronic administration of PLC, a significant increment in skeletal muscle uptake of {sup 99m}Tc-sestamibi was demonstrated without any apparent change in regional blood flow. This fact, if proven in further studies, may suggest a role for this tracer as a non-invasive probe of tissue bioenergetics. (orig.). With 4 figs., 4 tabs.

  19. Use of muscle synergies and wavelet transforms to identify fatigue during squatting.

    Science.gov (United States)

    Smale, Kenneth B; Shourijeh, Mohammad S; Benoit, Daniel L

    2016-06-01

    The objective of this study was to supplement continuous wavelet transforms with muscle synergies in a fatigue analysis to better describe the combination of decreased firing frequency and altered activation profiles during dynamic muscle contractions. Nine healthy young individuals completed the dynamic tasks before and after they squatted with a standard Olympic bar until complete exhaustion. Electromyography (EMG) profiles were analyzed with a novel concatenated non-negative matrix factorization method that decomposed EMG signals into muscle synergies. Muscle synergy analysis provides the activation pattern of the muscles while continuous wavelet transforms output the temporal frequency content of the EMG signals. Synergy analysis revealed subtle changes in two-legged squatting after fatigue while differences in one-legged squatting were more pronounced and included the shift from a general co-activation of muscles in the pre-fatigue state to a knee extensor dominant weighting post-fatigue. Continuous wavelet transforms showed major frequency content decreases in two-legged squatting after fatigue while very few frequency changes occurred in one-legged squatting. It was observed that the combination of methods is an effective way of describing muscle fatigue and that muscle activation patterns play a very important role in maintaining the overall joint kinetics after fatigue. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Diffusion Properties and 3D Architecture of Human Lower Leg Muscles Assessed with Ultra-High-Field-Strength Diffusion-Tensor MR Imaging and Tractography: Reproducibility and Sensitivity to Sex Difference and Intramuscular Variability.

    Science.gov (United States)

    Fouré, Alexandre; Ogier, Augustin C; Le Troter, Arnaud; Vilmen, Christophe; Feiweier, Thorsten; Guye, Maxime; Gondin, Julien; Besson, Pierre; Bendahan, David

    2018-05-01

    Purpose To demonstrate the reproducibility of the diffusion properties and three-dimensional structural organization measurements of the lower leg muscles by using diffusion-tensor imaging (DTI) assessed with ultra-high-field-strength (7.0-T) magnetic resonance (MR) imaging and tractography of skeletal muscle fibers. On the basis of robust statistical mapping analyses, this study also aimed at determining the sensitivity of the measurements to sex difference and intramuscular variability. Materials and Methods All examinations were performed with ethical review board approval; written informed consent was obtained from all volunteers. Reproducibility of diffusion tensor indexes assessment including eigenvalues, mean diffusivity, and fractional anisotropy (FA) as well as muscle volume and architecture (ie, fiber length and pennation angle) were characterized in lower leg muscles (n = 8). Intramuscular variability and sex differences were characterized in young healthy men and women (n = 10 in each group). Student t test, statistical parametric mapping, correlation coefficients (Spearman rho and Pearson product-moment) and coefficient of variation (CV) were used for statistical data analysis. Results High reproducibility of measurements (mean CV ± standard deviation, 4.6% ± 3.8) was determined in diffusion properties and architectural parameters. Significant sex differences were detected in FA (4.2% in women for the entire lower leg; P = .001) and muscle volume (21.7% in men for the entire lower leg; P = .008), whereas architecture parameters were almost identical across sex. Additional differences were found independently of sex in diffusion properties and architecture along several muscles of the lower leg. Conclusion The high-spatial-resolution DTI assessed with 7.0-T MR imaging allows a reproducible assessment of structural organization of superficial and deep muscles, giving indirect information on muscle function. © RSNA, 2018 Online supplemental material is

  1. Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication

    DEFF Research Database (Denmark)

    Mackey, Abigail L; Rasmussen, Lotte Klejs; Kadi, Fawzi

    2016-01-01

    muscles of one leg. Muscle biopsies were collected from the vastus lateralis muscles before and after stimulation (2.5 h and 2, 7, and 30 d) and were assessed for satellite cells and regeneration by immunohistochemistry and real-time RT-PCR, and we also measured telomere length. After injury, and compared...... activation of satellite cells and muscle remodeling during large-scale regeneration of injured human skeletal muscle.-Mackey, A. L., Rasmussen, L. K., Kadi, F., Schjerling, P., Helmark, I. C., Ponsot, E., Aagaard, P., Durigan, J. L. Q., Kjaer, M. Activation of satellite cells and the regeneration of human......With this study we investigated the role of nonsteroidal anti-inflammatory drugs (NSAIDs) in human skeletal muscle regeneration. Young men ingested NSAID [1200 mg/d ibuprofen (IBU)] or placebo (PLA) daily for 2 wk before and 4 wk after an electrical stimulation-induced injury to the leg extensor...

  2. Muscle morphometric effect of anterior cruciate ligament injury measured by computed tomography: aspects on using non-injured leg as control

    Science.gov (United States)

    2013-01-01

    Background Anterior cruciate ligament (ACL) tears are common, functionally disabling, and predispose to subsequent injuries and early onset of osteoarthritis in the knee. Injuries result in muscular atrophy and impaired muscular activation. To optimize surgical methods and rehabilitation strategies, knowledge of the effects of ACL injuries on muscles size and function is needed. Asymmetry due to limb dominance implies that the effect of ACL-injury might be different in right-sided and left-sided injuries which, should be taken in account when evaluating the effect of an injury. Evaluation of the effects of injuries is usually made with the contralateral leg as control. The aim of this study is to describe the effect of ACL-injuries on thigh muscle size and also to analyze feasibility of using contralateral limb as control. Methods Sixty-two patients scheduled to undergo ACL reconstruction were examined with computed tomography (CT). Muscle cross sectional area (CSA) was recorded for quadriceps, hamstrings, gracilis and sartorius 15 cm above the knee joint. Comparisons were made between the injured and non-injured side and between individuals separated by gender and side of injury. Comparisons were also made for patients with or without concomitant meniscal tear, for patients differing in time between injury and examinations and for patients with different level of physical activity after the injury. Results Quadriceps CSA was 5% smaller on the injured side. There was an indication that the muscles of the right thigh were generally bigger than those of the left thigh. The difference between the injured and the non-injured side was larger for right-sided injuries than for left-sided. There was also a greater difference in semimembranosus for women than for men. There were no differences related to meniscal injury, time since injury or physical activity. Conclusion The use of contralateral leg for evaluating the effect of ACL-injury is often the only available

  3. Mechanisms of activation of muscle branched-chain alpha-keto acid dehydrogenase during exercise in man

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; MacLean, D A; Saltin, B

    1996-01-01

    1. Exercise leads to activation (dephosphorylation) of the branched-chain alpha-keto acid dehydrogenase (BCKADH). Here we investigate the effect of low pre-exercise muscle glycogen content and of branched-chain amino acid (BCAA) ingestion on the activity of BCKADH at rest and after 90 min of one......-leg knee-extensor exercise at 65% maximal one-leg power output in five subjects. 2. Pre-exercise BCAA ingestion (308 mg BCAAs (kg body wt)-1) caused an increased muscle BCAA uptake, a higher intramuscular BCAA concentration and activation of BCKADH both at rest (9 +/- 1 versus 25 +/- 5% for the control...... and BCAA test, respectively) and after exercise (27 +/- 4 versus 54 +/- 7%). 3. At rest the percentage active BCKADH was not different, 6 +/- 2% versus 5 +/- 1%, in the normal and low glycogen content leg (392 +/- 21 and 147 +/- 34 mumol glycosyl units (g dry muscle)-1, respectively). The post...

  4. Low blood flow at onset of moderate intensity exercise does not limit muscle oxygen uptake

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan Peter; Saltin, Bengt

    2010-01-01

    The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion of i....... Additionally, prostanoids and/or NO appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise. Key words: Oxygen delivery, oxygen extraction, nitric oxide, prostanoids.......The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (NOS; L-NMMA) and cyclooxygenase (COX; indomethacin) in order to inhibit the synthesis of nitric oxide (NO) and prostanoids, respectively.. Leg blood flow and leg oxygen delivery throughout exercise was 25-50 % lower (P

  5. The neuromechanical functional contractile properties of the thigh muscles measured using tensiomyography in male athletes and non-athletes

    Directory of Open Access Journals (Sweden)

    Toskić Lazar

    2016-01-01

    Full Text Available Involuntary neuromechanical muscle contractile properties, especially of the extensor muscles and knee joint flexors as the largest muscle groups of the caudal part of the body, play an important role in both everyday movement and sport. Based on these data we can obtain important information on the functional properties of muscles. The basic means of evaluation of the functional involuntary neuromechanical muscles contractile properties is the non-invasive tensiomyographic method (TMG. The aim of this study was to determine the differences between the involuntary neuromechanical contractile properties of the thigh muscles measured using the TMG method on a sample of male athletes and non-athletes. The sample of participants was made up of 17 athletes and 10 non-athletes. By applying the multivariate analysis of variance (MANOVA and the t-test, we achieved results which indicate that of the overall 30 variables, a difference was determined among 13 of them. Most of the differences were determined for the extensor muscles of the right knee, especially of the rectus femoris muscle. It was also shown that in addition to the main knee joint extensor muscle (rectus femoris the main knee joint flexor muscle (biceps femoris also takes part in the definition of the difference between athletes and non-athletes. The results have shown that the following variables: contraction time (Tc and delay contraction time (Td are the functional parameters for which the highest difference between athletes and non-athletes were determined (from t = -2.284, p < 0.05 for the vastus lateralis of the right leg to t = -4.018, p < 0.01 for the rectus femoris of the left leg. These results have shown that it is possible to determine the differences in the functional involuntary neuromechanical contractile properties of the thigh muscles among trained and untrained individuals using the tensiomyographic method, but at the same time indicated that these differences were very

  6. Efficacy of Nintendo Wii Training on Mechanical Leg Muscle Function and Postural Balance in Community-Dwelling Older Adults

    DEFF Research Database (Denmark)

    Jorgensen, Martin G; Laessoe, Uffe; Hendriksen, Carsten

    2013-01-01

    BACKGROUND: Older adults show increased risk of falling and major risk factors include impaired lower extremity muscle strength and postural balance. However, the potential positive effect of biofeedback-based Nintendo Wii training on muscle strength and postural balance in older adults is unknown....... METHODS: This randomized controlled trial examined postural balance and muscle strength in community-dwelling older adults (75±6 years) pre- and post-10 weeks of biofeedback-based Nintendo Wii training (WII, n = 28) or daily use of ethylene vinyl acetate copolymer insoles (controls [CON], n = 30). Primary...... end points were maximal muscle strength (maximal voluntary contraction) and center of pressure velocity moment during bilateral static stance. RESULTS: Intention-to-treat analysis with adjustment for age, sex, and baseline level showed that the WII group had higher maximal voluntary contraction...

  7. Two weeks of one-leg immobilization decreases skeletal muscle respiratory capacity equally in young and elderly men

    DEFF Research Database (Denmark)

    Gram, Martin; Vigelsø Hansen, Andreas; Yokota, Takashi

    2014-01-01

    Physical inactivity affects human skeletal muscle mitochondrial oxidative capacity but the influence of aging combined with physical inactivity is not known. This study investigates the effect of two weeks of immobilization followed by six weeks of supervised cycle training on muscle oxidative...... capacity in 17 young (23±1years) and 15 elderly (68±1years) healthy men. We applied high-resolution respirometry in permeabilized fibers from muscle biopsies at inclusion after immobilization and training. Furthermore, protein content of mitochondrial complexes I-V, mitochondrial heat shock protein 70 (mt......HSP70) and voltage dependent anion channel (VDAC) were measured in skeletal muscle by Western blotting. The elderly men had lower content of complexes I-V and mtHSP70 but similar respiratory capacity and content of VDAC compared to the young. In both groups the respiratory capacity and protein content...

  8. The effect of swinging the arms on muscle activation and production of leg force during ski skating at different skiing speeds.

    Science.gov (United States)

    Göpfert, Caroline; Lindinger, Stefan J; Ohtonen, Olli; Rapp, Walter; Müller, Erich; Linnamo, Vesa

    2016-06-01

    The study investigated the effects of arm swing during leg push-off in V2-alternate/G4 skating on neuromuscular activation and force production by the leg muscles. Nine skilled cross-country skiers performed V2-alternate skating without poles at moderate, high, and maximal speeds, both with free (SWING) and restricted arm swing (NOSWING). Maximal speed was 5% greater in SWING (P<0.01), while neuromuscular activation and produced forces did not differ between techniques. At both moderate and high speed the maximal (2% and 5%, respectively) and average (both 5%) vertical force and associated impulse (10% and 14%) were greater with SWING (all P<0.05). At high speed range of motion and angular velocity of knee flexion were 24% greater with SWING (both P<0.05), while average EMG of m. biceps femoris was 31% lower (all P<0.05) in SWING. In a similar manner, the average EMG of m. vastus medialis and m. biceps femoris were lower (17% and 32%, P<0.05) during the following knee extension. Thus, swinging the arms while performing V2-alternate can enhance both maximal speed and skiing economy at moderate and, in particularly, high speeds. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Technetium-99m sestamibi leg scintigraphy for non-invasive assessment of propionyl-l-carnitine induced changes in skeletal muscle metabolism

    International Nuclear Information System (INIS)

    Cittanti, C.; Colamussi, P.; Giganti, M.; Orlandi, C.; Uccelli, L.; Manfrini, S.; Azzena, G.; Piffanelli, A.

    1997-01-01

    Carnitine derivatives, such as propionyl-l-carnitine (PLC), have been shown to improve walking distance in patients with obstructive peripheral artery disease (PAOD). The aim of this study was to ascertain whether technetium-99m sestamibi leg scintigraphy may be a useful tool in the evaluation of changes in skeletal muscle metabolism induced by chronic therapy with PLC. Twenty patients with clinical and instrumental evidence of PAOD were randomly assigned to a 3-month period of therapy with either PLC or placebo. Rest 99m Tc-sestamibi leg scintigraphy and echo-Doppler sonography were performed on all subjects immediately before and upon completion of the treatment period. At the end of the protocol the following results were observed in patients who underwent PLC administration: (a) a significant increase in both thigh and calf 99m Tc-sestamibi uptake, in comparison with baseline values (P 99m Tc-sestamibi was demonstrated without any apparent change in regional blood flow. This fact, if proven in further studies, may suggest a role for this tracer as a non-invasive probe of tissue bioenergetics. (orig.). With 4 figs., 4 tabs

  10. Protein turnover in the breast muscle of broiler chicks and studies addressing chlorine dioxide sanitation of hatching eggs, poultry leg problems and wheat middling diets for laying hens

    International Nuclear Information System (INIS)

    Patterson, P.H.

    1988-01-01

    Developmental changes occurred in breast muscle Ks measured by 14 C-tyrosine incorporation at 10, 16, 22 and 34 days of age. Protein synthesis rates decreased as the birds matures: 30 to 11.2%/d between 10 and 34 days of age. In a second study birds fed diets low in lysine or protein-energy had reduced fractional rates of protein synthesis and free tyrosine, branched chain and large neutral amino acid concentrations as compared to control birds the same body weight. Artificial weight loading and reduced dietary protein levels were used to study the effects of body weight on the severity of leg deformities in chicks and poults. Experiments investigating the practicality of wheat middlings as an alternate feedstuff for laying hens suggested that high levels in the diet will reduce egg production, feed conversion, hen livability and egg yolk color. Lastly, chlorine dioxide foam and dipping solutions were compared with formaldehyde fumigation for sanitizing hatching eggs

  11. Extramuscular myofascial force transmission within the rat anterior tibial compartment: Proximodistal differences in muscle force

    NARCIS (Netherlands)

    Huijing, P.A.J.B.M.; Baan, G.C.

    2001-01-01

    Intramuscular connective tissues are continuous to extramuscular connective tissues. If force is transmitted there, differences should be present between force at proximal and distal attachments of muscles. Extensor digitorum longus (EDL), tibialis anterior (TA), and extensor hallucis longus muscles

  12. Identification of hemostatic genes expressed in human and rat leg muscles and a novel gene (LPP1/PAP2A suppressed during prolonged physical inactivity (sitting

    Directory of Open Access Journals (Sweden)

    Zderic Theodore W

    2012-10-01

    Full Text Available Abstract Background Partly because of functional genomics, there has been a major paradigm shift from solely thinking of skeletal muscle as contractile machinery to an understanding that it can have roles in paracrine and endocrine functions. Physical inactivity is an established risk factor for some blood clotting disorders. The effects of inactivity during sitting are most alarming when a person develops the enigmatic condition in the legs called deep venous thrombosis (DVT or “coach syndrome,” caused in part by muscular inactivity. The goal of this study was to determine if skeletal muscle expresses genes with roles in hemostasis and if their expression level was responsive to muscular inactivity such as occurs in prolonged sitting. Methods Microarray analyses were performed on skeletal muscle samples from rats and humans to identify genes associated with hemostatic function that were significantly expressed above background based on multiple probe sets with perfect and mismatch sequences. Furthermore, we determined if any of these genes were responsive to models of physical inactivity. Multiple criteria were used to determine differential expression including significant expression above background, fold change, and non-parametric statistical tests. Results These studies demonstrate skeletal muscle tissue expresses at least 17 genes involved in hemostasis. These include the fibrinolytic factors tetranectin, annexin A2, and tPA; the anti-coagulant factors TFPI, protein C receptor, PAF acetylhydrolase; coagulation factors, and genes necessary for the posttranslational modification of these coagulation factors such as vitamin K epoxide reductase. Of special interest, lipid phosphate phosphatase-1 (LPP1/PAP2A, a key gene for degrading prothrombotic and proinflammatory lysophospholipids, was suppressed locally in muscle tissue within hours after sitting in humans; this was also observed after acute and chronic physical inactivity conditions

  13. Identification of hemostatic genes expressed in human and rat leg muscles and a novel gene (LPP1/PAP2A) suppressed during prolonged physical inactivity (sitting)

    Science.gov (United States)

    2012-01-01

    Background Partly because of functional genomics, there has been a major paradigm shift from solely thinking of skeletal muscle as contractile machinery to an understanding that it can have roles in paracrine and endocrine functions. Physical inactivity is an established risk factor for some blood clotting disorders. The effects of inactivity during sitting are most alarming when a person develops the enigmatic condition in the legs called deep venous thrombosis (DVT) or “coach syndrome,” caused in part by muscular inactivity. The goal of this study was to determine if skeletal muscle expresses genes with roles in hemostasis and if their expression level was responsive to muscular inactivity such as occurs in prolonged sitting. Methods Microarray analyses were performed on skeletal muscle samples from rats and humans to identify genes associated with hemostatic function that were significantly expressed above background based on multiple probe sets with perfect and mismatch sequences. Furthermore, we determined if any of these genes were responsive to models of physical inactivity. Multiple criteria were used to determine differential expression including significant expression above background, fold change, and non-parametric statistical tests. Results These studies demonstrate skeletal muscle tissue expresses at least 17 genes involved in hemostasis. These include the fibrinolytic factors tetranectin, annexin A2, and tPA; the anti-coagulant factors TFPI, protein C receptor, PAF acetylhydrolase; coagulation factors, and genes necessary for the posttranslational modification of these coagulation factors such as vitamin K epoxide reductase. Of special interest, lipid phosphate phosphatase-1 (LPP1/PAP2A), a key gene for degrading prothrombotic and proinflammatory lysophospholipids, was suppressed locally in muscle tissue within hours after sitting in humans; this was also observed after acute and chronic physical inactivity conditions in rats, and exercise was

  14. Transversal stiffness of fibers and desmin content in leg muscles of rats under gravitational unloading of various durations.

    Science.gov (United States)

    Ogneva, I V

    2010-12-01

    The aim of this research was the analysis of structural changes in various parts of the sarcolemma and contractile apparatus of muscle fibers by measuring their transversal stiffness by atomic force microscopy under gravitational unloading. Soleus, medial gastrocnemius, and tibialis anterior muscles of Wistar rats were the objects of the study. Gravitational unloading was carried out by antiorthostatic suspension of hindlimbs for 1, 3, 7, and 12 days. It was shown that the transversal stiffness of different parts of the contractile apparatus of soleus muscle fibers decreases during gravitational unloading in the relaxed, calcium-activated, and rigor states, the fibers of the medial gastrocnemius show no changes, whereas the transversal stiffness of tibialis anterior muscle increases. Thus the transversal stiffness of the sarcolemma in the relaxed state is reduced in all muscles, which may be due to the direct action of gravity as an external mechanical factor that can influence the tension on a membrane. The change of sarcolemma stiffness in activated fibers, which is due probably to the transfer of tension from the contractile apparatus, correlates with the dynamics of changes in the content of desmin.

  15. Intra-rater reliability and agreement of muscle strength, power and functional performance measures in patients with hip osteoarthritis

    DEFF Research Database (Denmark)

    Bieler, Theresa; Magnusson, S Peter; Kjær, Michael

    2014-01-01

    OBJECTIVE: To investigate the reliability and agreement of measures of lower extremity muscle strength, power and functional performance in patients with hip osteoarthritis at different time intervals, and to compare these with the same measures in healthy peers. DESIGN: Intra-rater test...... extensor power, and functional performance (8-foot Up & Go, stair climbing, chair stand and 6-min walk) were measured in patients, and quadriceps strength, leg extensor power and functional performance were measured in healthy peers. Systematic error, reliability and agreement were calculated. RESULTS......-retest separated by 1, 2, or 2.5 weeks in patients, and 1 week in healthy peers. SUBJECTS: Patients with hip osteoarthritis (age range 61-83 years) with 1 (n = 37), 2 (n = 35), or 2.5 weeks (n = 15) between tests, and 35 healthy peers (age range 63-82 years). METHODS: Maximal isometric hip and thigh strength, leg...

  16. Hemodynamic changes in rat leg muscles during tourniquet-induced ischemia-reperfusion injury observed by near-infrared spectroscopy

    International Nuclear Information System (INIS)

    Kim, J G; Lee, J; Tromberg, B J; Brenner, M; Roe, J; Walters, T J

    2009-01-01

    In this study, we hypothesized that non-invasive continuous wave near-infrared spectroscopy (CWNIRS) can determine the severity or reversibility of muscle damage due to ischemia/reperfusion (I/R), and the results will be highly correlated with those from physical examination and histological analysis. To test this hypothesis, we performed CWNIRS measurements on two groups of male Sprague-Dawley rats (∼400 g) that underwent 2 h (n = 6) or 3 h (n = 7) of pneumatic tourniquet application (TKA). Tissue oxyhemoglobin [HbO 2 ] and deoxyhemoglobin [Hb] concentration changes were monitored during the 2 h or 3 h of 250 mmHg TKA and for an additional 2 h post-TKA. Rats were euthanized 24 h post-TKA and examined for injury, edema and viability of muscles. Contralateral muscles served as controls for each animal. In both groups, [HbO 2 ] dropped immediately, then gradually decreased further after TKA and then recovered once the tourniquet was released. However, releasing after 2 h of TKA caused [HbO 2 ] to overshoot above the baseline during reperfusion while the 3 h group continued to have lower [HbO 2 ] than baseline. We found a significant correlation between the elapsed time from tourniquet release to the first recovery peak of [HbO 2 ] and the muscle weight ratio between tourniquet and contralateral limb muscles (R = 0.86). Hemodynamic patterns from non-invasive CWNIRS demonstrated significant differences between 2 h and 3 h I/R. The results demonstrate that CWNIRS may be useful as a non-invasive prognostic tool for conditions involving vascular compromise such as extremity compartment syndrome

  17. [Reconstruction of the extensor pollicis longus tendon by transposition of the extensor indicis tendon].

    Science.gov (United States)

    Loos, A; Kalb, K; Van Schoonhoven, J; Landsleitner Dagger, B

    2003-12-01

    Rupture of the extensor pollicis longus-tendon (EPL) is a frequent complication after distal radius fractures. Other traumatic and non-traumatic reasons for this tendon lesion are known, including a theory about a disorder in the blood supply to the tendon itself. We examined 40 patients after reconstruction of the EPL-tendon in a mean follow-up time of 30 months. All patients were clinically examined and a DASH questionnaire was answered by all patients. The method to reconstruct the EPL-tendon was the transposition of the extensor indicis-tendon. After the operations the thumb was put in a splint for four weeks in a "hitch-hiker's-position". 31 ruptures of the tendon (77.5 %) were a result of trauma. In 20 of them (50 %) a distal radius fracture had occurred. Clinical examination included measurements of the movement of the thumb- and index-finger joints, the grip strength and the maximal span of the hand. Significant differences were not found. The isolated extension of the index finger was possible in all patients. But it was reduced in ten cases which represent 25 %. Our results were evaluated by the Geldmacher score to evaluate the reconstruction of the EPL-tendon. 20 % excellent, 65 % good, 12.5 % fair and 2.5 % poor results were reached. The Geldmacher score was used critically. We suggest its modification for the evaluation of thumb abduction. The DASH score reached a functional value of ten points which represents a very good result. In conclusion the extensor indicis-transposition is a safe method to reconstruct the EPL-tendon. Its substantial advantage is taking a healthy muscle as the motor, thereby avoiding the risk of using a degenerated muscle in late tendon reconstruction. A powerful extension of the index finger will be maintained by physical education. Generally, the loss of the extension of the index finger is negligible. It does not disturb the patients. But it has to be discussed with the patient before the operation.

  18. A practical approach to assess leg muscle oxygenation during ramp-incremental cycle ergometry in heart failure

    Directory of Open Access Journals (Sweden)

    A.C. Barroco

    2017-10-01

    Full Text Available Heart failure is characterized by the inability of the cardiovascular system to maintain oxygen (O2 delivery (i.e., muscle blood flow in non-hypoxemic patients to meet O2 demands. The resulting increase in fractional O2 extraction can be non-invasively tracked by deoxygenated hemoglobin concentration (deoxi-Hb as measured by near-infrared spectroscopy (NIRS. We aimed to establish a simplified approach to extract deoxi-Hb-based indices of impaired muscle O2 delivery during rapidly-incrementing exercise in heart failure. We continuously probed the right vastus lateralis muscle with continuous-wave NIRS during a ramp-incremental cardiopulmonary exercise test in 10 patients (left ventricular ejection fraction <35% and 10 age-matched healthy males. Deoxi-Hb is reported as % of total response (onset to peak exercise in relation to work rate. Patients showed lower maximum exercise capacity and O2 uptake-work rate than controls (P<0.05. The deoxi-Hb response profile as a function of work rate was S-shaped in all subjects, i.e., it presented three distinct phases. Increased muscle deoxygenation in patients compared to controls was demonstrated by: i a steeper mid-exercise deoxi-Hb-work rate slope (2.2±1.3 vs 1.0±0.3% peak/W, respectively; P<0.05, and ii late-exercise increase in deoxi-Hb, which contrasted with stable or decreasing deoxi-Hb in all controls. Steeper deoxi-Hb-work rate slope was associated with lower peak work rate in patients (r=–0.73; P=0.01. This simplified approach to deoxi-Hb interpretation might prove useful in clinical settings to quantify impairments in O2 delivery by NIRS during ramp-incremental exercise in individual heart failure patients.

  19. Haemodynamic responses to exercise, ATP infusion and thigh compression in humans: insight into the role of muscle mechanisms on cardiovascular function

    DEFF Research Database (Denmark)

    Gonzalez-Alonso, J.; Mortensen, S.P.; Jeppesen, Tina Dysgaard

    2008-01-01

    on cardiovascular function during exercise, we determined leg and systemic haemodynamic responses in healthy men during (1) incremental one-legged knee-extensor exercise, (2) step-wise femoral artery ATP infusion at rest, (3) passive exercise (n=10), (4)femoral vein or artery ATP infusion (n=6), and (5) cyclic...... exercise also increased blood flow (DeltaLBF 0.7 +/- 0.1 l min(-1)), yet the increase in muscle and systemic perfusion, unrelated to elevations in aerobic metabolism, accounted only for approximately 5% of peak exercise hyperaemia.Likewise, thigh compressions alone or in combination with passive exercise...

  20. The Effect of Ratio of Contraction to Relaxation Durations in PNF Exercises on the Muscle Strength and Range of Motion of Hip Joint

    Directory of Open Access Journals (Sweden)

    Hossein Rashedi

    2015-09-01

    Full Text Available Objective: The aim of the present study was to compare the effect of ratios of contraction- Relaxation on the muscle strength and range of motion of hip joint in PNF exercises. Methods: Thirty nine nonathletic male students (Mean±SD; age, 13±1.2 years; body mass, 55±9.8 kg were assigned .Three groups designated as I, II and III groups. The ratios of contraction to relaxation periods for groups were 1, 2 and 3 respectively. Training program included three sessions per week (CR-PNF for 6 weeks. Measurements of hip extensors muscles stretch and strength were performed at the beginning and at the end of training using an inclinometer (during leg raise test and dynamometer. Data were analyzed using dependent samples t-test and one-way ANOVA. Results: The results of the present study showed significant increases in hip extensor muscles flexibility and strength for three groups. This increase the in the strength in group I equaled 6 kg, in group II 4 kg and in group III 7 kg. The amount of increase in the hip extensor muscles flexibility in group I, II and II were 15, 8 and 12 degrees, respectively. The increase in these two variables was significant and similar in all three groups. Conclusion: Different contraction to relaxation ratio normally, 0.5, 1 and 2, did not show any meaningful differences on hip extensor muscular strength and hip range of motion.

  1. Postexercise blood flow restriction does not enhance muscle hypertrophy induced by multiple-set high-load resistance exercise.

    Science.gov (United States)

    Madarame, Haruhiko; Nakada, Satoshi; Ohta, Takahisa; Ishii, Naokata

    2018-05-01

    To test the applicability of postexercise blood flow restriction (PEBFR) in practical training programmes, we investigated whether PEBFR enhances muscle hypertrophy induced by multiple-set high-load resistance exercise (RE). Seven men completed an eight-week RE programme for knee extensor muscles. Employing a within-subject design, one leg was subjected to RE + PEBFR, whereas contralateral leg to RE only. On each exercise session, participants performed three sets of unilateral knee extension exercise at approximately 70% of their one-repetition maximum for RE leg first, and then performed three sets for RE + PEBFR leg. Immediately after completion of the third set, the proximal portion of the RE + PEBFR leg was compressed with an air-pressure cuff for 5 min at a pressure ranging from 100 to 150 mmHg. If participants could perform 10 repetitions for three sets in two consecutive exercise sessions, the work load was increased by 5% at the next exercise session. Muscle thickness and strength of knee extensor muscles were measured before and after the eight-week training period and after the subsequent eight-week detraining period. There was a main effect of time but no condition × time interaction or main effect of condition for muscle thickness and strength. Both muscle thickness and strength increased after the training period independent of the condition. This result suggests that PEBFR would not be an effective training method at least in an early phase of adaptation to high-load resistance exercise. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  2. The relation between knee muscle strength and performance tests in orienteering athletes.

    Science.gov (United States)

    Çinar-Medeni, Özge; Colakoglu, Fatma F; Yüce, Koray; Ipekoğlu, Gökhan; Baltaci, Gul

    2016-11-01

    The aim of this study was to analyze the effect of knee muscle strength on performance tests in orienteers. Thirty-seven orienteers were voluntarily included in this study. Isokinetic knee flexor and extensor muscles' strength was assessed at 120°/s velocity for both "dominant leg" (DL) and "non-dominant leg" (NDL). "Single-legged hop test" (SLHT), "flamingo balance test" (FBT), "star excursion balance test" (SEBT), vertical jump-and-reach test (for anaerobic power), T-drill test and 20-meter shuttle run test (for aerobic power) were carried out. Correlation and regression analyses were performed on the data. VO2max levels showed moderate correlations with DL's "flexor peak torque" (FPT) and NDL's "extensor peak torque" (EPT) and FPT values respectively (r=0.49, r=0.38, r=0.58). FPT of NDL was a predictor of VO2max level (R2=0.33). Anaerobic power has a relationship with EPT of NDL (r=0.43) and T-drill test with EPT and FPT values of both DL and NDL respectively (r=-0.35, r=-0.63, r=-0.53, r=-0.58). EPT of NDL was a predictor for anaerobic power (R2=0.19) and FPT of DL for agility (R2=0.40). Nonparametric linear regression results showed that EPT is a predictor in DL (median slope=-0.71, P=0.01), and FPT in NDL (median slope=-0.90, P=0.006) for FBT. FPT was a predictor of SEBT scores for both legs (0.13extensor muscle strength are of importance to improve orienteering performance.

  3. Efficacy of Nintendo Wii training on mechanical leg muscle function and postural balance in community-dwelling older adults: a randomized controlled trial.

    Science.gov (United States)

    Jorgensen, Martin G; Laessoe, Uffe; Hendriksen, Carsten; Nielsen, Ole Bruno Faurholt; Aagaard, Per

    2013-07-01

    Older adults show increased risk of falling and major risk factors include impaired lower extremity muscle strength and postural balance. However, the potential positive effect of biofeedback-based Nintendo Wii training on muscle strength and postural balance in older adults is unknown. This randomized controlled trial examined postural balance and muscle strength in community-dwelling older adults (75±6 years) pre- and post-10 weeks of biofeedback-based Nintendo Wii training (WII, n = 28) or daily use of ethylene vinyl acetate copolymer insoles (controls [CON], n = 30). Primary end points were maximal muscle strength (maximal voluntary contraction) and center of pressure velocity moment during bilateral static stance. Intention-to-treat analysis with adjustment for age, sex, and baseline level showed that the WII group had higher maximal voluntary contraction strength (18%) than the control group at follow up (between-group difference = 269 N, 95% CI = 122; 416, and p = .001). In contrast, the center of pressure velocity moment did not differ (1%) between WII and CON at follow-up (between-group difference = 0.23 mm(2)/s, 95% CI = -4.1; 4.6, and p = .92). For secondary end points, pre-to-post changes favoring the WII group were evident in the rate of force development (p = .03), Timed Up and Go test (p = .01), short Falls Efficacy Scale-International (p = .03), and 30-second repeated Chair Stand Test (p = .01). Finally, participants rated the Wii training highly motivating at 5 and 10 weeks into the intervention. Biofeedback-based Wii training led to marked improvements in maximal leg muscle strength (maximal voluntary contraction; rate of force development) and overall functional performance in community-dwelling older adults. Unexpectedly, static bilateral postural balance remained unaltered with Wii training. The high level of participant motivation suggests that biofeedback-based Wii exercise may ensure a high degree of compliance to home- and/or community

  4. Fiber orientation measurements by diffusion tensor imaging improve hydrogen-1 magnetic resonance spectroscopy of intramyocellular lipids in human leg muscles.

    Science.gov (United States)

    Valaparla, Sunil K; Gao, Feng; Daniele, Giuseppe; Abdul-Ghani, Muhammad; Clarke, Geoffrey D

    2015-04-01

    Twelve healthy subjects underwent hydrogen-1 magnetic resonance spectroscopy ([Formula: see text]) acquisition ([Formula: see text]), diffusion tensor imaging (DTI) with a [Formula: see text]-value of [Formula: see text], and fat-water magnetic resonance imaging (MRI) using the Dixon method. Subject-specific muscle fiber orientation, derived from DTI, was used to estimate the lipid proton spectral chemical shift. Pennation angles were measured as 23.78 deg in vastus lateralis (VL), 17.06 deg in soleus (SO), and 8.49 deg in tibialis anterior (TA) resulting in a chemical shift between extramyocellular lipids (EMCL) and intramyocellular lipids (IMCL) of 0.15, 0.17, and 0.19 ppm, respectively. IMCL concentrations were [Formula: see text], [Formula: see text], and [Formula: see text] in SO, VL, and TA, respectively. Significant differences were observed in IMCL and EMCL pairwise comparisons in SO, VL, and TA ([Formula: see text]). Strong correlations were observed between total fat fractions from [Formula: see text] and Dixon MRI for VL ([Formula: see text]), SO ([Formula: see text]), and TA ([Formula: see text]). Bland-Altman analysis between fat fractions (FFMRS and FFMRI) showed good agreement with small limits of agreement (LoA): [Formula: see text] (LoA: [Formula: see text] to 0.69%) in VL, [Formula: see text] (LoA: [Formula: see text] to 1.33%) in SO, and [Formula: see text] (LoA: [Formula: see text] to 0.47%) in TA. The results of this study demonstrate the variation in muscle fiber orientation and lipid concentrations in these three skeletal muscle types.

  5. Enhanced muscle blood flow with intermittent pneumatic compression of the lower leg during plantar flexion exercise and recovery.

    Science.gov (United States)

    Zuj, K A; Prince, C N; Hughson, R L; Peterson, S D

    2018-02-01

    This study tested the hypothesis that intermittent compression of the lower limb would increase blood flow during exercise and postexercise recovery. Data were collected from 12 healthy individuals (8 men) who performed 3 min of standing plantar flexion exercise. The following three conditions were tested: no applied compression (NoComp), compression during the exercise period only (ExComp), and compression during 2 min of standing postexercise recovery. Doppler ultrasound was used to determine superficial femoral artery (SFA) blood flow responses. Mean arterial pressure (MAP) and cardiac stroke volume (SV) were assessed using finger photoplethysmography, with vascular conductance (VC) calculated as VC = SFA flow/MAP. Compared with the NoComp condition, compression resulted in increased MAP during exercise [+3.5 ± 4.1 mmHg (mean ± SD)] but not during postexercise recovery (+1.6 ± 5.9 mmHg). SV increased with compression during both exercise (+4.8 ± 5.1 ml) and recovery (+8.0 ± 6.6 ml) compared with NoComp. There was a greater increase in SFA flow with compression during exercise (+52.1 ± 57.2 ml/min) and during recovery (+58.6 ± 56.7 ml/min). VC immediately following exercise was also significantly greater in the ExComp condition compared with the NoComp condition (+0.57 ± 0.42 ml·min -1 ·mmHg -1 ), suggesting the observed increase in blood flow during exercise was in part because of changes in VC. Results from this study support the hypothesis that intermittent compression applied during exercise and recovery from exercise results in increased limb blood flow, potentially contributing to changes in exercise performance and recovery. NEW & NOTEWORTHY Blood flow to working skeletal muscle is achieved in part through the rhythmic actions of the skeletal muscle pump. This study demonstrated that the application of intermittent pneumatic compression during the diastolic phase of the cardiac cycle, to mimic the mechanical

  6. Assessment of leg muscle activity using toe tapping in patients with Parkinson's disease: comparison of two types of toe tapping.

    Science.gov (United States)

    Taniguchi, Seira; Peper, Ferdinand; Shimokawa, Tetsuya

    2018-05-01

    [Purpose] This study investigates two types of toe tapping, i.e., "closed," with both feet on the floor, and "open," in which the foot does not touch the ground, and evaluates their usefulness in combination with monitoring of muscle activity during toe tapping. [Subjects and Methods] The study enrolled 11 patients with Parkinson's disease (PD) and 9 controls (Controls). The tibialis anterior (TA) and gastrocnemius (GS) muscle activity during toe tapping was measured using surface electromyography. [Results] In closed tapping, the minima in GS activation with the first tap was significantly higher in patients with PD than in Controls. In open tapping, the coefficient of variation (CV) of local maxima in TA activation was significantly higher in patients with PD than in Controls. In both types of tapping, the CV of extrema in GS activities increased with disease duration, but this may be due to the long-term administration of Levodopa, which itself tends to cause excessive GS activities. [Conclusion] Closed tapping is suitable for the assessment of GS activity and can detect excessive activities, which is observed as visible movement. Open tapping, on the other hand, is suitable for assessment of TA activity.

  7. 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

  8. Distribution of skeletal muscle involvement in autosomal recessive distal muscular dystrophy

    International Nuclear Information System (INIS)

    Mizusawa, Hidehiro; Nakanishi, Takao; Kobayashi, Fumie.

    1987-01-01

    Distribution of skeletal muscle involvement in 5 cases with autosomal recessive distal muscular dystrophy was studied clinically and by computed tomography (CT). Manual muscle test showed muscle involvement with a predilection for flexors in the lower leg and adductors in the thigh. Flexion and extension of the thigh and the lower leg was impaired to similar degree. In progressed cases, neck flexors and trunk muscles were also affected mildly. CT disclosed more clearly the preferential involvement of flexors in the lower leg, and involvement of both hamstrings · adductors group and extensors group of the thigh to similar degree. However, m. popliteus was curiously well preserved. In addition, there was a stage showing high density and hypertrophy of m. sartorius, m. gracilis, m. adductor, m. biceps femoris, m. semimenbranosus, m. semitendinosus or m. rectus femoris, which in thought to be compensatory hypertrophy. M. gluteus minimus in the pelvic girdle and m. dorsi proprii in the trunk were also liable to be affected. The CT findings are regarded as characteristic features noted clearly before muscle weakness and atrophy become apparent clinically. CT is very useful for distinguishing distal muscular dystrophy from rimmed vacuolar distal myopathy in which m. quadriceps femoris and flexors of the lower leg are usually well preserved without compensatory hypertrophy on CT. (author)

  9. Bilateral movements increase sustained extensor force in the paretic arm.

    Science.gov (United States)

    Kang, Nyeonju; Cauraugh, James H

    2018-04-01

    Muscle weakness in the extensors poststroke is a common motor impairment. Unfortunately, research is unclear on whether bilateral movements increase extensor force production in the paretic arm. This study investigated sustained force production while stroke individuals maximally extended their wrist and fingers on their paretic arm. Specifically, we determined isometric force production in three conditions: (a) unilateral paretic arm, (b) unilateral nonparetic arm, and (c) bilateral (both arms executing the same movement simultaneously). Seventeen chronic stroke patients produced isometric sustained force by executing wrist and fingers extension in unilateral and bilateral contraction conditions. Mean force, force variability (coefficient of variation), and signal-to-noise ratio were calculated for each contraction condition. Analysis of two-way (Arm × Type of Condition: 2 × 2; Paretic or Nonparetic Arm × Unilateral or Bilateral Conditions) within-subjects ANOVAs revealed that the bilateral condition increased sustained force in the paretic arm, but reduced sustained force in the nonparetic arm. Further, although the paretic arm exhibited more force variability and less signal-to-noise ratio than the nonparetic arm during a unilateral condition, there were no differences when participants simultaneously executed isometric contractions with both arms. Our unique findings indicate that bilateral contractions transiently increased extensor force in the paretic arm. Implications for Rehabilitation Bilateral movements increased isometric wrsit extensor force in paretic arms and redcued force in nonparetic arms versus unilateral movements. Both paretic and nonparetic arms produced similar force variability and signal-to-noise ratio during bilateral movements. Increased sustained force in the paretic arm during the bilateral condition indicates that rehabilitation protocols based on bilateral movements may be beneficial for functional recovery.

  10. Four cases of variations in the forearm extensor musculature in a study of hundred limbs and review of literature

    Directory of Open Access Journals (Sweden)

    Rao Mohandas

    2006-01-01

    Full Text Available All surgeons must bear in mind the existence of muscular variations when performing common tendon transfers. Presence of additional bellies and tendons of existing muscles or presence of additional muscles in unusual locations might misguide a surgeon, during surgery and also during diagnosis. In the present paper we are reporting four cases of variations encountered during the study of extensor muscles of the forearm in 100 limbs. In Case 1, additional bellies of extensor carpi radialis longus and extensor carpi radialis brevis and multiple tendons of insertion of abductor pollicis longus were observed in a single limb. In Case 2, an additional belly of the abductor pollicis longus was observed. In Case 3, a short muscle on the dorsum of the hand going to the index finger [extensor indicis brevis (EIB] was found in addition to the normal extensor indicis (EI. It was also observed that some of the most superficial fleshy fibers of EIB were getting inserted into the tendon of EI. In Case 4, a rare incidence of extensor digiti medii proprius was observed. Further, the related literature is reviewed and the clinical and surgical importance of these muscular variations in diagnosis and proper planning of treatment is discussed.

  11. The automatic pelvic floor muscle response to the active straight leg raise in cases with pelvic girdle pain and matched controls.

    Science.gov (United States)

    Stuge, Britt; Sætre, Kaja; Ingeborg Hoff, Brækken

    2013-08-01

    The active straight leg raise (ASLR) test has been proposed as a clinical test for the assessment of pelvic girdle pain (PGP). Little is known about the activation of the pelvic floor muscles (PFM) during ASLR. The main aim of this study was to examine the automatic PFM contraction during ASLR. Specific aims were to compare automatic contraction to rest and to voluntary contraction, to compare PFM contraction during ASLR with and without compression and to examine whether there were any differences in PFM contraction between women with and without clinically diagnosed PGP during ASLR. Forty-nine pairs of women participated in a cross-sectional study with individual, one-to-one matched cases and controls. PFM was assessed by reliable and valid 3D ultrasound at rest, during voluntary and automatic contraction. Test-retest data for the levator hiatus during ASLR showed good repeatability. Significantly automatic PFM contractions occurred when ASLR tests were performed. There was a strong positive correlation between voluntary and automatic PFM contractions. Manual compression reduced the automatic PFM contraction during ASLR by 62-66%. There were no significant differences between cases and controls in reduction of levator hiatus or muscle length from rest to automatic contractions during ASLR. Interestingly, a significantly smaller levator hiatus was found in women with PGP than in controls, at rest, during an automatic contraction with ASLR and during voluntary contraction. In conclusion, a significant automatic PFM contraction occurred during ASLR, both in cases and in controls. Women with PGP had a significantly smaller levator hiatus than controls. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Effects of a low-intensity strength-training program on knee-extensor strength and functional ability of frail older people

    NARCIS (Netherlands)

    Westhoff, M.H.; Stemmerik, L.; Boshuizen, H.C.

    2000-01-01

    This study's purpose was to investigate whether a 10-week low-intensity strength-training program could improve strength of the knee extensors and functional ability. Participants 65 years and older with low knee-extensor muscle strength were randomized into an exercise (n = 11) and a control group

  13. Surgery-induced changes and early recovery of hip-muscle strength, leg-press power, and functional performance after fast-track total hip arthroplasty: a prospective cohort study.

    Directory of Open Access Journals (Sweden)

    Bente Holm

    Full Text Available By measuring very early changes in muscle strength and functional performance after fast-track total hip arthroplasty (THA, post-operative rehabilitation, introduced soon after surgery, can be designed to specifically target identified deficits.Firstly, to quantify changes (compared to pre-operative values in hip muscle strength, leg-press power, and functional performance in the first week after THA, and secondly, to explore relationships between the muscle strength changes, and changes in hip pain, systemic inflammation, and thigh swelling.Prospective, cohort study.Convenience sample of patients receiving a THA at Copenhagen University Hospital, Hvidovre, Denmark, between March and December 2011.Thirty-five patients (65.9 ± 7.2 years undergoing THA.Hip muscle strength, leg-press power, performance-based function, and self-reported disability were determined prior to, and 2 and 8 days after, THA (Day 2 and 8, respectively. Hip pain, thigh swelling, and C-Reactive Protein were also determined.Five patients were lost to follow-up. Hip muscle strength and leg press power were substantially reduced at Day 2 (range of reductions: 41-58%, P<0.001, but less pronounced at Day 8 (range of reductions: 23-31%, P<0.017. Self-reported symptoms and function (HOOS: Pain, Symptoms, and ADL improved at Day 8 (P<0.014. Changes in hip pain, C-Reactive Protein, and thigh swelling were not related to the muscle strength and power losses.Hip muscle strength and leg-press power decreased substantially in the first week after THA - especially at Day 2 - with some recovery at Day 8. The muscle strength loss and power loss were not related to changes in hip pain, systemic inflammation, or thigh swelling. In contrast, self-reported symptoms and function improved. These data on surgery-induced changes in muscle strength may help design impairment-directed, post-operative rehabilitation to be introduced soon after surgery.ClinicalTrials.gov NCT01246674.

  14. Functional adaptation of tendon and skeletal muscle to resistance training in three patients with genetically verified classic Ehlers Danlos Syndrome

    DEFF Research Database (Denmark)

    Møller, Mathias Bech; Kjær, Michael; Svensson, René Brüggebusch

    2014-01-01

    undergoing muscle strength training. We investigated patients with classical Ehlers Danlos Syndrome (EDS) (collagen type V defect) who display articular hypermobility, skin extensibility and tissue fragility. METHODS: subjects underwent strength training 3 times a week for 4 months and were tested before...... and after intervention in regards to muscle strength, tendon mechanical properties, and muscle function. RESULTS: three subjects completed the scheduled 48 sessions and had no major adverse events. Mean isometric leg extension force and leg extensor power both increased by 8 and 11% respectively (358 to 397...... sway-area of the participants decreased by 26% (0.144 to 0.108 m(2)). On the subscale of CIS20 the participants lowered their average subjective fatigue score from 33 to 25. CONCLUSION: in this small pilot study, heavy resistance training was both feasible and effective in classic Ehlers Danlos...

  15. Adiposity, physical activity, and muscle quality are independently related to physical function performance in middle-aged postmenopausal women.

    Science.gov (United States)

    Ward-Ritacco, Christie L; Adrian, Amanda L; Johnson, Mary Ann; Rogers, Laura Q; Evans, Ellen M

    2014-10-01

    Poor physical function performance is associated with risks for disability in late life; however, determinants of physical function are not well characterized in middle-aged women. The aim of this cross-sectional study was to examine the contributions of body composition, physical activity, muscle capacity, and muscle quality to physical function performance. Postmenopausal women (N = 64; mean [SD] age, 58.6 [3.6] y) were assessed for body composition via dual-energy x-ray absorptiometry, for physical activity via accelerometer (steps per day), and for physical function via Timed Up and Go, 30-second chair stand, and 6-minute walk. Leg strength was assessed using isokinetic dynamometry at 60° second. Leg power was assessed with the Nottingham Leg Extensor Power Rig. Muscle quality was calculated as (1) the ratio of leg strength at 60° second to upper leg lean mass and (2) the ratio of leg power to total lower body lean mass. Regression analyses revealed the following: (1) age and muscle quality calculated with leg power are independently related to Timed Up and Go, explaining 12% and 11% of the variance, respectively (P quality calculated with leg strength are independently related to 30-second chair stand, explaining 12% and 10% of the variance, respectively (P quality calculated with leg strength, steps per day, and adiposity are independent predictors of 6-minute walk, collectively explaining 51% of the variance. In postmenopausal women, a more optimal body composition (including lower adiposity and higher lean mass) and higher levels of physical activity are associated with better physical function performance at midlife.

  16. Assessment of leg muscles mechanical capacities: Which jump, loading, and variable type provide the most reliable outcomes?

    Science.gov (United States)

    García-Ramos, Amador; Feriche, Belén; Pérez-Castilla, Alejandro; Padial, Paulino; Jaric, Slobodan

    2017-07-01

    This study aimed to explore the strength of the force-velocity (F-V) relationship of lower limb muscles and the reliability of its parameters (maximum force [F 0 ], slope [a], maximum velocity [V 0 ], and maximum power [P 0 ]). Twenty-three men were tested in two different jump types (squat and countermovement jump: SJ and CMJ), performed under two different loading conditions (free weight and Smith machine: Free and Smith) with 0, 17, 30, 45, 60, and 75 kg loads. The maximum and averaged values of F and V were obtained for the F-V relationship modelling. All F-V relationships were strong and linear independently whether observed from the averaged across the participants (r ≥ 0.98) or individual data (r = 0.94-0.98), while their parameters were generally highly reliable (F 0 [CV: 4.85%, ICC: 0.87], V 0 [CV: 6.10%, ICC: 0.82], a [CV: 10.5%, ICC: 0.81], and P 0 [CV: 3.5%, ICC: 0.93]). Both the strength of the F-V relationships and the reliability of their parameters were significantly higher for (1) the CMJ over the SJ, (2) the Free over the Smith loading type, and (3) the maximum over the averaged F and V variables. In conclusion, although the F-V relationships obtained from all the jumps tested were linear and generally highly reliable, the less appropriate choice for testing the F-V relationship could be through the averaged F and V data obtained from the SJ performed either in a Free weight or in a Smith machine. Insubstantial differences exist among the other combinations tested.

  17. Comparative anatomy and muscle architecture of selected hind limb muscles in the Quarter Horse and Arab.

    Science.gov (United States)

    Crook, T C; Cruickshank, S E; McGowan, C M; Stubbs, N; Wakeling, J M; Wilson, A M; Payne, R C

    2008-02-01

    The Quarter Horse (bred for acceleration) and the Arab (bred for endurance) are situated at either end of the equine athletic spectrum. Studies into the form and function of the leg muscles in human sprint and endurance runners have demonstrated that differences exist in their muscle architecture. It is not known whether similar differences exist in the horse. Six Quarter Horse and six Arab fresh hind limb cadavers were dissected to gain information on the muscle mass and architecture of the following muscles: gluteus medius; biceps femoris; semitendinosus; vastus lateralis; gastrocnemius; tibialis cranialis and extensor digitorum longus. Specifically, muscle mass, fascicle length and pennation angle were quantified and physiological cross-sectional area (PCSA) and maximum isometric force were estimated. The hind limb muscles of the Quarter Horse were of a significantly greater mass, but had similar fascicle lengths and pennation angles when compared with those of the Arab; this resulted in the Quarter Horse hind limb muscles having greater PCSAs and hence greater isometric force potential. This study suggests that Quarter Horses as a breed inherently possess large strong hind limb muscles, with the potential to accelerate their body mass more rapidly than those of the Arab.

  18. Does change in isolated lumbar extensor muscle function correlate with good clinical outcome? A secondary analysis of data on change in isolated lumbar extension strength, pain, and disability in chronic low back pain.

    Science.gov (United States)

    Steele, James; Fisher, James; Perrin, Craig; Conway, Rebecca; Bruce-Low, Stewart; Smith, Dave

    2018-01-12

    Secondary analysis of data from studies utilising isolated lumbar extension exercise interventions for correlations among changes in isolated lumbar extension strength, pain, and disability. Studies reporting isolated lumbar extension strength changes were examined for inclusion criteria including: (1) participants with chronic low back pain, (2) intervention ≥ four weeks including isolated lumbar extension exercise, (3) outcome measures including isolated lumbar extension strength, pain (Visual Analogue Scale), and disability (Oswestry Disability Index). Six studies encompassing 281 participants were included. Correlations among change in isolated lumbar extension strength, pain, and disability. Participants were grouped as "met" or "not met" based on minimal clinically important changes and between groups comparisons conducted. Isolated lumbar extension strength and Visual Analogue Scale pooled analysis showed significant weak to moderate correlations (r = -0.391 to -0.539, all p Disability Index pooled analysis showed significant weak correlations (r = -0.349 to -0.470, all p disability, isolated lumbar extension strength changes were greater for those "met" compared with those "not met" (p disability. This study shows significant correlations between increases in isolated lumbar extension strength and reductions in pain and disability. Strengthening of the lumbar extensor musculature could be considered an important target for exercise interventions.

  19. Neuromuscular blockade of slow twitch muscle fibres elevates muscle oxygen uptake and energy turnover during submaximal exercise in humans

    DEFF Research Database (Denmark)

    Krustrup, Peter; Secher, Niels; Relu, Mihai U.

    2008-01-01

    We tested the hypothesis that a greater activation of fast-twitch (FT) fibres during dynamic exercise leads to a higher muscle oxygen uptake (VO2 ) and energy turnover as well as a slower muscle on-kinetics. Subjects performed one-legged knee-extensor exercise for 10 min at an intensity of 30 W...... without (CON) and with (CUR) arterial injections of the non-depolarizing neuromuscular blocking agent cisatracurium. In CUR, creatine phosphate (CP) was unaltered in slow twitch (ST) fibres and decreased (P fibres, whereas in CON, CP decreased (P ... at a contraction frequency of 1 Hz, and that the muscle VO2 kinetics is slowed by FT fibre activation....

  20. Relationship between Muscle Function, Muscle Typology and Postural Performance According to Different Postural Conditions in Young and Older Adults.

    Science.gov (United States)

    Paillard, Thierry

    2017-01-01

    Although motor output of the postural function clearly influences postural performance in young and older subjects, no relationship has been formally established between them. However, the relationship between lower-extremity muscle strength/power and postural performance is often pointed out, especially in older subjects. In fact, the influence of motor output may vary according to the postural condition considered (e.g., static, dynamic, challenging, disturbing). In static postural condition, there may be a relationship between lower-extremity muscle strength and postural performance when the value of muscle strength is below a certain threshold in older subjects. Above this threshold of muscle strength, this relationship may disappear. In dynamic postural condition, lower-extremity muscle power could facilitate compensatory postural actions, limiting induced body imbalance likely to generate falls in older subjects. In young subjects, there could be a relationship between very early rapid torque of the leg extensor muscles and postural performance. In the case of postural reaction to (external) perturbations, a high percentage of type II muscle fibers could be associated with the ability to react quickly to postural perturbations in young subjects, while it may enable a reduction in the risk of falls in older subjects. In practice, in older subjects, muscle strength and/or power training contributes to reducing the risk of falls, as well as slowing down the involution of muscle typology regarding type II muscle fibers.

  1. Skeletal muscle water T2 as a biomarker of disease status and exercise effects in patients with Duchenne muscular dystrophy.

    Science.gov (United States)

    Mankodi, Ami; Azzabou, Noura; Bulea, Thomas; Reyngoudt, Harmen; Shimellis, Hirity; Ren, Yupeng; Kim, Eunhee; Fischbeck, Kenneth H; Carlier, Pierre G

    2017-08-01

    The purpose of this study was to examine exercise effects on muscle water T 2 in patients with Duchenne muscular dystrophy (DMD). In 12 DMD subjects and 19 controls, lower leg muscle fat (%) was measured by Dixon and muscle water T 2 and R 2 (1/T 2 ) by the tri-exponential model. Muscle water R 2 was measured again at 3 hours after an ankle dorsiflexion exercise. The muscle fat fraction was higher in DMD participants than in controls (p muscle. Muscle water T 2 was measured independent of the degree of fatty degeneration in DMD muscle. At baseline, muscle water T 2 was higher in all but the extensor digitorum longus muscles of DMD participants than controls (p muscle torque (p muscle water R 2 decreased (T 2 increased) after exercise from baseline in DMD subjects and controls with greater changes in the target muscles of the exercise than in ankle plantarflexor muscles. Skeletal muscle water T 2 is a sensitive biomarker of the disease status in DMD and of the exercise response in DMD patients and controls. Published by Elsevier B.V.

  2. Impulsive ankle push-off powers leg swing in human walking.

    Science.gov (United States)

    Lipfert, Susanne W; Günther, Michael; Renjewski, Daniel; Seyfarth, Andre

    2014-04-15

    Rapid unloading and a peak in power output of the ankle joint have been widely observed during push-off in human walking. Model-based studies hypothesize that this push-off causes redirection of the body center of mass just before touch-down of the leading leg. Other research suggests that work done by the ankle extensors provides kinetic energy for the initiation of swing. Also, muscle work is suggested to power a catapult-like action in late stance of human walking. However, there is a lack of knowledge about the biomechanical process leading to this widely observed high power output of the ankle extensors. In our study, we use kinematic and dynamic data of human walking collected at speeds between 0.5 and 2.5 m s(-1) for a comprehensive analysis of push-off mechanics. We identify two distinct phases, which divide the push-off: first, starting with positive ankle power output, an alleviation phase, where the trailing leg is alleviated from supporting the body mass, and second, a launching phase, where stored energy in the ankle joint is released. Our results show a release of just a small part of the energy stored in the ankle joint during the alleviation phase. A larger impulse for the trailing leg than for the remaining body is observed during the launching phase. Here, the buckling knee joint inhibits transfer of power from the ankle to the remaining body. It appears that swing initiation profits from an impulsive ankle push-off resulting from a catapult without escapement.

  3. Utilização do esfigmomanômetro na avaliação da força dos músculos extensores e flexores da articulação do joelho em militares Utilización del esfigmomanómetro en la evaluación de la fuerza de los músculos extensores y flexores de la articulación de la rodilla en militares Use of the sphygmomanometer in the evaluation of the knee joint flexor and extensor muscle strength in militaries

    Directory of Open Access Journals (Sweden)

    Claudionor Delgado

    2004-10-01

    ón se obtuvieron en la prueba de ejecución (Make test, en la mesa flexo-extensora Inbaf y registradas por EM Tycos. El análisis de los datos fue descriptiva, aplicándose la prueba "t" de Student para comparar los valores promedios, adoptándose un nivel de significancia de p 0,05. En los ángulos de 90 grados para la extensión y 30 grados para la flexión de la rodilla, no se observaron diferencias significativas intragrupos (p BASES AND OBJECTIVE: This is a comparative and descriptive study that aims at analyzing the strength for the different angles of the knee flexion and extension in militaries. The objective of this study was to evaluate the extensor and flexor muscles of the knee joint for different angles by means of the Modified Sphygmomanometer (MS in healthy militaries. METHODS: The sample was composed of 31 militaries as follows: 19 male and 12 female with average age of 26.5 ± 5.8 years; respective average height of 162.00 ± 0.06 (cm and 175.00 ± 0.06 (cm and average body mass of 56.83 ± 5.85 (kg and 73.25 ± 10.46 (kg. The evaluation methodology was the one proposed by Helewa, Goldsmith and Smithe (1981 using Modified Sphygmomanometer (MS. The maximal isometric contractions at 30º of flexion and 30º/90º of extension were obtained in the Make test, in the Inbaf flexion-extension table and recorded by the MS Tycos. The data was analyzed using the "t" Student-test to compare the averages, and the significance level adopted was p > 0.05. RESULTS: In both the female and the male groups, significant difference was only observed between angles of 30 and 90 degrees of the right knee extension (p > 0.05. At angles of 90 degrees for the knee extension and of 30 degrees for knee flexion, no intra-groups significant differences were observed (p > 0.05. CONCLUSION: Militaries present strength differences between knee joint anterior and posterior muscular groups at the different angles studied. The methodology used showed to be satisfactory for the strength

  4. Oral glucose ingestion attenuates exercise-induced activation of 5'-AMP-activated protein kinase in human skeletal muscle

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Birk, Jesper Bratz; Klein, Ditte Kjærsgaard

    2006-01-01

    5'-AMP-activated protein kinase (AMPK) has been suggested to be a 'metabolic master switch' regulating various aspects of muscle glucose and fat metabolism. In isolated rat skeletal muscle, glucose suppresses the activity of AMPK and in human muscle glycogen loading decreases exercise-induced AMPK...... activation. We hypothesized that oral glucose ingestion during exercise would attenuate muscle AMPK activation. Nine male subjects performed two bouts of one-legged knee-extensor exercise at 60% of maximal workload. The subjects were randomly assigned to either consume a glucose containing drink or a placebo...... drink during the two trials. Muscle biopsies were taken from the vastus lateralis before and after 2 h of exercise. Plasma glucose was higher (6.0 +/- 0.2 vs. 4.9 +/- 0.1 mmol L-1, P

  5. Distribution of skeletal muscle involvement in autosomal recessive distal muscular dystrophy. A clinical and computed tomographic study

    Energy Technology Data Exchange (ETDEWEB)

    Mizusawa, Hidehiro; Nakanishi, Takao; Kobayashi, Fumie

    1987-02-01

    Distribution of skeletal muscle involvement in 5 cases with autosomal recessive distal muscular dystrophy was studied clinically and by computed tomography (CT). Manual muscle test showed muscle involvement with a predilection for flexors in the lower leg and adductors in the thigh. Flexion and extension of the thigh and the lower leg was impaired to similar degree. In progressed cases, neck flexors and trunk muscles were also affected mildly. CT disclosed more clearly the preferential involvement of flexors in the lower leg, and involvement of both hamstrings center dot adductors group and extensors group of the thigh to similar degree. However, m. popliteus was curiously well preserved. In addition, there was a stage showing high density and hypertrophy of m. sartorius, m. gracilis, m. adductor, m. biceps femoris, m. semimenbranosus, m. semitendinosus or m. rectus femoris, which in thought to be compensatory hypertrophy. M. gluteus minimus in the pelvic girdle and m. dorsi proprii in the trunk were also liable to be affected. The CT findings are regarded as characteristic features noted clearly before muscle weakness and atrophy become apparent clinically. CT is very useful for distinguishing distal muscular dystrophy from rimmed vacuolar distal myopathy in which m. quadriceps femoris and flexors of the lower leg are usually well preserved without compensatory hypertrophy on CT.

  6. Training and muscle ammonia and amino acid metabolism in humans during prolonged exercise

    DEFF Research Database (Denmark)

    Graham, T E; Turcotte, L P; Kiens, Bente

    1995-01-01

    We studied the responses of NH3 and amino acids (AA) to prolonged exercise (3 h) in trained (Tr; n = 6) and untrained (Utr; n = 6) men. Each subject exercised the knee extensor muscles of one leg at 60% of maximum capacity. Thigh blood flow and femoral arteriovenous differences (0, 30, 60, 120, 150......, and 180 min) as well as muscle biopsies (0, 120, and 180 min) were taken for NH3 and AA measurements. In both groups, muscle Glu decreased (P ....4 +/- 6.8 mmol/kg wet wt in Tr and Utr, respectively. Tr had greater (P muscle Tau, Phe, Ala, and Glu. Both groups had a large Glu uptake and effluxes of NH3, Gln, and Ala as well as essential AA. The latter implies that there was a net protein catabolism. The efflux of NH3 and Gln was much...

  7. Exercise induced effects on muscle function and range of motion in patients with hip osteoarthritis

    DEFF Research Database (Denmark)

    Bieler, Theresa; Siersma, Volkert; Magnusson, S Peter

    2018-01-01

    BACKGROUND AND PURPOSE: Patients with hip osteoarthritis have impairments in muscle function (muscle strength and power) and hip range of motion (ROM), and it is commonly believed that effective clinical management of osteoarthritis should address these impairments to reduce pain and disability......-two patients were randomized to either 4 months of physiotherapist-supervised, moderate, progressive, strength training (n = 50), physiotherapist-supervised NW (n = 50), or unsupervised HBE (n = 52). Maximal isometric hip and thigh muscle strength and leg extensor power and active hip ROM were assessed...... at baseline 2, 4, and 12 months. RESULTS: Intention-to-treat-analyses did not show any significant between-group differences for improvements in muscle strength and power or ROM at any time points. Short-term significant (p

  8. Injury of leg somatotopy of corticospinal tract at corona radiata by ventriculoperitoneal shunt: A case report.

    Science.gov (United States)

    Jang, Sung Ho; Kwon, Younghyeon

    2018-03-01

    A 45-year-old right-handed female patient suffered head trauma after being hit by a truck that ran into a house. The patient lost consciousness for 1 hour and experienced posttraumatic amnesia for 1 month after the accident. She underwent conservative management for a subdural hematoma in the left frontotemporal lobes and intracerebral hematoma in the left frontal lobe. The patient's Glasgow Coma Scale score was 11. She underwent a VP shunt operation, approached through the right posterior parietal area of the brain, at 4 months after onset. Approximately, 6 months after onset, she was admitted to the rehabilitation department of a university hospital. She presented with moderate weakness of the left leg: Medical Research Council scores: hip flexor; 3, knee extensor; 3+, ankle dorsiflexor; 3-. Brain magnetic resonance imaging revealed a leukomalactic lesion in the right posterior corona radiata along the shunt. On 6-month (2 months after the shunt operation) diffusion tensor tractography, the left CST showed partial injury in the posterior portion compared with the right CST. On 6-month transcranial magnetic stimulation study, the motor-evoked potential obtained at the left tibialis anterior muscle revealed lower amplitude than that on the right side. Injury of leg somatotopy of a CST was demonstrated in a patient with leg weakness following a VP shunt operation.

  9. Relationship between isometric thigh muscle strength and minimum clinically important differences in knee function in osteoarthritis: data from the osteoarthritis initiative.

    Science.gov (United States)

    Ruhdorfer, Anja; Wirth, Wolfgang; Eckstein, Felix

    2015-04-01

    To determine the relationship between thigh muscle strength and clinically relevant differences in self-assessed lower leg function. Isometric knee extensor and flexor strength of 4,553 Osteoarthritis Initiative participants (2,651 women and 1,902 men) was related to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function scores by linear regression. Further, groups of male and female participant strata with minimum clinically important differences (MCIDs) in WOMAC function scores (6 of 68 units) were compared across the full range of observed values and to participants without functional deficits (WOMAC score 0). The effect of WOMAC knee pain and body mass index on the above relationships was explored using stepwise regression. Per regression equations, a 3.7% reduction in extensor strength and a 4.0% reduction in flexor strength were associated with an MCID in WOMAC function in women, and, respectively, a 3.6% and 4.8% reduction in men. For strength divided by body weight, reductions were 5.2% and 6.7%, respectively, in women and 5.8% and 6.7%, respectively, in men. Comparing MCID strata across the full observed range of WOMAC function confirmed the above estimates and did not suggest nonlinear relationships across the spectrum of observed values. WOMAC pain correlated strongly with WOMAC function, but extensor (and flexor) muscle strength contributed significant independent information. Reductions of approximately 4% in isometric muscle strength and of 6% in strength per body weight were related to a clinically relevant difference in WOMAC functional disability. Longitudinal studies will need to confirm these relationships within persons. Muscle extensor (and flexor) strength (per body weight) provided significant independent information in addition to pain in explaining variability in lower leg function. Copyright © 2015 by the American College of Rheumatology.

  10. Inibição muscular dos extensores do joelho em sujeitos acometidos por condromalácia patelar e osteoartrite do joelho - um estudo de revisão sistemática Knee extensor muscle inhibition in subjects with chondromalacia patellae and knee osteoarthritis - a systematic review

    Directory of Open Access Journals (Sweden)

    Klauber Dalcero Pompeo

    2012-06-01

    Full Text Available A inibição muscular (IM tem sido reportada como um dos fatores associados à fraqueza muscular presente na osteoartrite (OA e condromalácia patelar (CP, sendo inclusive associada com a etiologia e a progressão. Entretanto, parece existir uma lacuna na literatura em relação a estudos de revisão que avaliaram o grau de IM de sujeitos acometidos por CP e OA. O objetivo do estudo foi reunir os resultados de estudos que investigaram o grau de IM na OA e CP e identificar possíveis diferenças na IM que estejam associadas aos estágios do processo degenerativo. Foram incluídos nesta revisão sistemática estudos transversais e/ou experimentais publicados nas bases de dados PubMed, Scopus, SciELO e Cochrane entre 1990 e 2010 que avaliaram a IM por meio da técnica de interpolação de abalo publicados. Os dados referentes à população, protocolo de IM, qualidade dos estudos e resultados de IM foram sumariados e apresentados em Tabelas. Para análise da qualidade, utilizou-se a escala de PEDro. Após a aplicação dos critérios de inclusão, 13 artigos foram incluídos na revisão sistemática (OA=9 e CP=4. A partir da análise dos dados, observou-se uma IM maior na CP em comparação à OA. Contudo, a variabilidade metodológica e a falta de informações sobre os protocolos de IM indicam a necessidade de novos estudos experimentais a fim de que se possa determinar com maior precisão a relação entre a IM e as doenças degenerativas articulares.Muscle inhibition (MI has been reported as one of the factors associated with muscle weakness present in osteoarthritis (OA and chondromalacia patellae (CP, including being associated with the etiology and progression. However, there seems to be a gap in the literature regarding the review studies that assessed the degree of IM subjects affected by CP and OA. The main objective of study was bringing together the results of studies that investigated the degree of OA in the MI and CP and to identify

  11. PGC-1beta is downregulated by training in human skeletal muscle: no effect of training twice every second day vs. once daily on expression of the PGC-1 family

    DEFF Research Database (Denmark)

    Mortensen, Ole Hartvig; Plomgaard, Peter; Fischer, Christian P

    2007-01-01

    We hypothesized that the peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) family of transcriptional coactivators (PGC-1alpha, PGC-1beta, and PRC) is differentially regulated by training once daily vs. training twice daily every second day and that this difference might...... be observed in the acute response to endurance exercise. Furthermore, we hypothesized that expression levels of the PGC-1 family differ with muscular fiber-type composition. Thus, before and after 10 wk of knee extensor endurance training, training one leg once daily and the other leg twice daily every second...... day, keeping the total amount of training for the legs equal, skeletal muscle mRNA expression levels of PGC-1alpha, PGC-1beta, and PRC were determined in young healthy men (n = 7) in response to 3 h of acute exercise. No significant difference was found between the two legs, suggesting that regulation...

  12. Broken Leg

    Science.gov (United States)

    ... the leg, which can result in a fracture. Stress fractures outside of sport situations are more common in people who have: ... shoes. Choose the appropriate shoe for your favorite sports or activities. And ... can prevent stress fractures. Rotate running with swimming or biking. If ...

  13. Levels of myosin heavy chain mRNA transcripts and protein isoforms in the fast extensor digitorum longus muscle of 7-month-old rats with chronic thyroid status alterations

    Czech Academy of Sciences Publication Activity Database

    Vadászová, Adriana; Hudecová, S.; Križanová, O.; Soukup, Tomáš

    2006-01-01

    Roč. 55, č. 6 (2006), s. 707-710 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA304/05/0327 Grant - others:VEGA(SK) 2/4106; NATO(XE) 979876; SAV(SK) APVT-51-027404; MYORES(XE) 511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : myosin heavy chain isoforms * thyroid hormones * muscle differentiation Subject RIV: ED - Physiology Impact factor: 2.093, year: 2006

  14. Degree of thoracic kyphosis and peak torque of trunk flexors and extensors among healthy women.

    Science.gov (United States)

    Granito, Renata Neves; Aveiro, Mariana Chaves; Rennó, Ana Claudia Muniz; Oishi, Jorge; Driusso, Patricia

    2014-01-01

    The aim of this study was to analyze the effects of aging on the degree of thoracic kyphosis and peak torque of the trunk flexor and extensor muscles among women without a densitometric diagnosis of osteoporosis. Thirty women were selected to make up three groups: young women (n = 10; 24.60 ± 2.27 years of age); adults (n = 10; 43.50 ± 2.88); and elderly women (n = 10; 62.40 ± 2.67). Bone mineral density (BMD), degree of thoracic kyphosis and peak torque of the trunk flexors and extensors were evaluated. Differences between the groups were evaluated using the Kruskal-Wallis ANOVA and Mann-Whitney U tests. Pearson's correlation coefficient was used to assess correlations between the variables. The significance level was taken to be 5% (p ≤ 0.05). The elderly group presented a greater degree of thoracic kyphosis (p = 0.009) and lower peak torque of the trunk flexors and extensors than the young group. The adult group presented lower peak torque of the trunk than the young group. A negative correlation was observed between age and peak torque of the trunk flexors and extensors (p ≤ 0.001), and a positive correlation between age and the degree of thoracic kyphosis (r = 0.58; p ≤ 0.001). The elderly group presented higher values for the eccentric/concentric ratio of the peak torque for flexors (p = 0.03) and extensors (p = 0.02). This study suggests that physiological aging may be associated with a greater degree of thoracic kyphosis and lower muscle strength of the trunk flexors and extensors. Moreover, the elderly women showed a relative capacity for preservation of eccentric strength.

  15. Degree of thoracic kyphosis and peak torque of trunk flexors and extensors among healthy women,

    Directory of Open Access Journals (Sweden)

    Renata Neves Granito

    2014-06-01

    Full Text Available OBJECTIVE: The aim of this study was to analyze the effects of aging on the degree of thoracic kyphosis and peak torque of the trunk flexor and extensor muscles among women without a densitometric diagnosis of osteoporosis.METHODS: Thirty women were selected to make up three groups: young women (n = 10; 24.60 ± 2.27 years of age; adults (n = 10; 43.50 ± 2.88; and elderly women (n= 10; 62.40 ± 2.67. Bone mineral density (BMD, degree of thoracic kyphosis and peak torque of the trunk flexors and extensors were evaluated. Differences between the groups were evaluated using the Kruskal-Wallis ANOVA and Mann-Whitney U tests. Pearson's correlation coefficient was used to assess correlations between the variables. The significance level was taken to be 5% (p < 0.05.RESULTS: The elderly group presented a greater degree of thoracic kyphosis (p = 0.009 and lower peak torque of the trunk flexors and extensors than the young group. The adult group presented lower peak torque of the trunk than the young group. A negative correlation was observed between age and peak torque of the trunk flexors and extensors (p < 0.001, and a positive correlation between age and the degree of thoracic kyphosis (r = 0.58; p < 0.001. The elderly group presented higher values for the eccentric/concentric ratio of the peak torque for flexors (p = 0.03 and extensors (p = 0.02.CONCLUSION: This study suggests that physiological aging may be associated with a greater degree of thoracic kyphosis and lower muscle strength of the trunk flexors and extensors. Moreover, the elderly women showed a relative capacity for preservation of eccentric strength.

  16. Isometric elbow extensors strength in supine- and prone-lying positions.

    Science.gov (United States)

    Abdelzaher, Ibrahim E; Ababneh, Anas F; Alzyoud, Jehad M

    2013-01-01

    The purpose of this study was to compare isometric strength of elbow extensors measured in supine- and prone-lying positions at elbow flexion angles of 45 and 90 degrees. Twenty-two male subjects under single-blind procedures participated in the study. Each subject participated in both supine-lying and prone-lying measuring protocols. Calibrated cable tensiometer was used to measure isometric strength of the right elbow extensors and a biofeedback electromyography was used to assure no substitution movements from shoulder girdle muscles. The mean values of isometric strength of elbow extensors measured from supine-lying position at elbow flexion angles of 45 and 90 degrees were 11.1  ±  4.2 kg and 13.1  ±  4.6 kg, while those measured from prone-lying position were 9.9  ±  3.6 kg and 12  ±  4.2 kg, respectively. There is statistical significant difference between the isometric strength of elbow extensors measured from supine-lying position at elbow flexion angles of 45 and 90 degrees compared to that measured from prone-lying position (p  isometric strength of elbow extensors since supine-lying starting position is better than prone-lying starting position.

  17. Multi-slice MRI reveals heterogeneity in disease distribution along the length of muscle in Duchenne muscular dystrophy.

    Science.gov (United States)

    Chrzanowski, Stephen M; Baligand, Celine; Willcocks, Rebecca J; Deol, Jasjit; Schmalfuss, Ilona; Lott, Donovan J; Daniels, Michael J; Senesac, Claudia; Walter, Glenn A; Vandenborne, Krista

    2017-09-01

    Duchenne muscular dystrophy (DMD) causes progressive pathologic changes to muscle secondary to a cascade of inflammation, lipid deposition, and fibrosis. Clinically, this manifests as progressive weakness, functional loss, and premature mortality. Though insult to whole muscle groups is well established, less is known about the relationship between intramuscular pathology and function. Differences of intramuscular heterogeneity across muscle length were assessed using an ordinal MRI grading scale in lower leg muscles of boys with DMD and correlated to patient's functional status. Cross sectional T 1 weighted MRI images with fat suppression were obtained from ambulatory boys with DMD. Six muscles (tibialis anterior, extensor digitorum longus, peroneus, soleus, medial and lateral gastrocnemii) were graded using an ordinal grading scale over 5 slice sections along the lower leg length. The scores from each slice were combined and results were compared to global motor function and age. Statistically greater differences of involvement were observed at the proximal ends of muscle compared to the midbellies. Multi-slice assessment correlated significantly to age and the Vignos functional scale, whereas single-slice assessment correlated to the Vignos functional scale only. Lastly, differential disease involvement of whole muscle groups and intramuscular heterogeneity were observed amongst similar age subjects. A multi-slice ordinal MRI grading scale revealed that muscles are not uniformly affected, with more advanced disease visible near the tendons in a primarily ambulatory population with DMD. A geographically comprehensive evaluation of the heterogeneously affected muscle in boys with DMD may more accurately assess disease involvement.

  18. Six weeks' aerobic retraining after two weeks' immobilization restores leg lean mass and aerobic capacity but does not fully rehabilitate leg strenght in young and older men

    DEFF Research Database (Denmark)

    Vigelsø Hansen, Andreas; Gram, Martin; Wiuff, Caroline

    2015-01-01

    OBJECTIVE: To determine the effect of aerobic retraining as rehabilitation after short-term leg immobilization on leg strength, leg work capacity, leg lean mass, leg muscle fibre type composition and leg capillary supply, in young and older men. SUBJECTS AND DESIGN: Seventeen young (23 ± 1 years...... immobilization had marked effects on leg strength, and work capacity and 6 weeks' retraining was sufficient to increase, but not completely rehabilitate, muscle strength, and to rehabilitate aerobic work capacity and leg lean mass (in the young men)....

  19. Effects of strength training program on hip extensors and knee extensors strength of lower limb in children with spastic diplegic cerebral palsy.

    Science.gov (United States)

    Aye, Thanda; Thein, Soe; Hlaing, Thaingi

    2016-01-01

    [Purpose] The purpose of this study was to determine whether strength training programs for hip extensors and knee extensors improve gross motor function of children with cerebral palsy in Myanmar. [Subjects and Methods] Forty children (25 boys and 15 girls, mean age: 6.07 ± 2.74 years) from National Rehabilitation Hospital, Yangon, Myanmar, who had been diagnosed with spastic diplegic cerebral palsy, Gross Motor Classification System I and II participated in a 6-week strength training program (45 minutes per day, 3 days per week) on hip and knee extensors. Assessment was made, before and after intervention, of the amount of training weight in pounds, as well as Gross Motor Function Measure (GMFM) dimensions D (standing) and E (walking, running, jumping). [Results] All scores had increased significantly after the strength-training program. [Conclusion] A simple method of strength-training program for hip and knee extensors might lead to improved muscle strength and gross motor function in children with spastic diplegic cerebral palsy.

  20. Neuromuscular blockade of slow twitch muscle fibres elevates muscle oxygen uptake and energy turnover during submaximal exercise in humans.

    Science.gov (United States)

    Krustrup, Peter; Secher, Niels H; Relu, Mihai U; Hellsten, Ylva; Söderlund, Karin; Bangsbo, Jens

    2008-12-15

    We tested the hypothesis that a greater activation of fast-twitch (FT) fibres during dynamic exercise leads to a higher muscle oxygen uptake (VO2 ) and energy turnover as well as a slower muscle on-kinetics. Subjects performed one-legged knee-extensor exercise for 10 min at an intensity of 30 W without (CON) and with (CUR) arterial injections of the non-depolarizing neuromuscular blocking agent cisatracurium. In CUR, creatine phosphate (CP) was unaltered in slow twitch (ST) fibres and decreased (P fibres, whereas in CON, CP decreased (P fibres, respectively. From 127 s of exercise, muscle VO2 was higher (P muscle VO2 response was slower (P muscle homogenate CP was lowered (P muscle lactate production was similar in CUR and CON (37.8 +/- 4.1 versus 35.2 +/- 6.2 mmol). Estimated total muscle ATP turnover was 19% higher (P fibres are less efficient than ST fibres in vivo at a contraction frequency of 1 Hz, and that the muscle VO2 kinetics is slowed by FT fibre activation.

  1. Bed rest reduces metabolic protein content and abolishes exercise-induced mRNA responses in human skeletal muscle

    DEFF Research Database (Denmark)

    Jørgensen, Stine Ringholm; Biensø, Rasmus S; Kiilerich, Kristian

    2011-01-01

    Background: The aim was to test the hypothesis that one week of bed rest will reduce mitochondrial number and expression and activity of oxidative proteins in human skeletal muscle, but that exercise-induced intracellular signaling as well as mRNA and microRNA (miR) responses are maintained after......-legged knee extensor exercise performed before and after bed rest. Results: Maximal oxygen uptake decreased 5% and exercise endurance decreased non-significantly 25% by bed rest. Bed rest reduced skeletal muscle mitochondrial DNA/nuclear DNA content 15%, hexokinase II and sirtuin 1 protein content ~45%, 3...... bed rest. Research Design and Methods: Twelve young, healthy, male subjects completed 7 days of bed rest with vastus lateralis muscle biopsies taken before and after bed rest. In addition, muscle biopsies were obtained from 6 of the subjects prior to, immediately after and 3h after 45 min one...

  2. Muscle cramps

    Science.gov (United States)

    ... the lower leg/calf Back of the thigh (hamstrings) Front of the thigh (quadriceps) Cramps in the ... Names Cramps - muscle Images Chest stretch Groin stretch Hamstring stretch Hip stretch Thigh stretch Triceps stretch References ...

  3. Dystrophic calcification in muscles of legs in calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia syndrome: Accurate evaluation of the extent with 99mTc-methylene diphosphonate single photon emission computed tomography/computed tomography

    International Nuclear Information System (INIS)

    Chakraborty, Partha Sarathi; Karunanithi, Sellam; Dhull, Varun Singh; Kumar, Kunal; Tripathi, Madhavi

    2015-01-01

    We present the case of a 35-year-old man with calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia variant scleroderma who presented with dysphagia, Raynaud's phenomenon and calf pain. 99m Tc-methylene diphosphonate bone scintigraphy was performed to identify the extent of the calcification. It revealed extensive dystrophic calcification in the left thigh and bilateral legs which was involving the muscles and was well-delineated on single photon emission computed tomography/computed tomography. Calcinosis in scleroderma usually involves the skin but can be found in deeper periarticular tissues. Myopathy is associated with a poor prognosis

  4. Dynamic extensor brace for lateral epicondylitis.

    NARCIS (Netherlands)

    Faes, M.C.; Akker, B. van den; Lint, J.A. de; Kooloos, J.G.M.; Hopman, M.T.E.

    2006-01-01

    Lateral epicondylitis (tennis elbow) is a common, often disabling ailment. Based on the failure of current therapies, a new dynamic extensor brace has been developed. In this study, the effects of application of this brace for 3 months on the most important and disabling symptoms of patients with

  5. Isometric hip muscle strength in posttraumatic below-knee amputees

    Directory of Open Access Journals (Sweden)

    Jandrić Slavica

    2007-01-01

    Full Text Available Background/Aim. Traumas and war injuries, next to chronic occlusive artery disease and diabetes mellitus-derived complications, are the most frequent cause of the lower limbs amputation. They affect mostly younger population that need a higher level of activities as compared with the elderly. Medical rehabilitation is very significant for the muscle performance improvement in this population providing their social reintegration. The aim of this study was to investigate the effect of below-knee amputation on the hip isometric muscle strength and effect of rehabilitation on improvement of hip muscle strength in below-knee amputees, secondary to war wounding. Methods. Forty below-knee amputees (after war wounding, average age 35.6±10.6 years, that were included in primary rehabilitation program with prosthetics, were examined. Objective parameters were used to evaluate therapeutical effects. Isometric muscle strength of hip flexors, extensors, abductors and adductors was measured by dynamometer and expressed in Newton (N at admission, control and discharge for each patient. Average length of the treatment was 51 ± 34.1 days. Results. For isometric hip flexors (t = - 1.99346, p < 0.05, extensors (t = -4.629073, p < 0.001, abductors (t = -4.9408, p < 0.001 and adductors (t = -2.00228, p < 0.05, muscle strength was significantly less on the amputated than on nonamputated side. The highest differences in muscle strength between amputated and nonamputated limbs were noted for hip abductors (26.6% and extensors (23.3%. There was significant improvement of mean values of strength for all examined hip muscles after rehabilitation and prosthetics for both legs in comparison to beginning of the therapy. The hip abductor on the amputated side was for 19.4% weaker after rehabilitation in comparison to the nonamputated limb. Conclusion. Decreases of isometric muscle strength in all examined hip muscles were observed, more in the amputated limb. Rehabilitation

  6. Exercise training, but not resveratrol, improves metabolic and inflammatory status in skeletal muscle of aged men

    DEFF Research Database (Denmark)

    Olesen, Jesper; Gliemann Hybholt, Lasse; Biensøe, Rasmus S

    2014-01-01

    Aim: To investigate the metabolic and anti-inflammatory effects of resveratrol alone and when combined with exercise training in skeletal muscle of aged human subjects. Material and Methods: Healthy physically inactive men (60-72 year old) were randomized into either 8 weeks of daily intake of 250...... mg resveratrol or placebo or into 8 weeks of high intensity exercise training with 250 mg resveratrol or placebo. Before and after the interventions, resting blood samples and muscle biopsies were obtained and a one-leg knee-extensor endurance exercise test (KEE) was performed. Results: Exercise...... with no significant additive or adverse effects of resveratrol on these parameters. Despite an overall ~25% reduction in total acetylation level in skeletal muscle with resveratrol, no exclusive resveratrol-mediated metabolic effects were observed on the investigated parameters. Notably however, resveratrol blunted...

  7. Electrophysiologic evaluation of lumbosacral single nerve roots using compound muscle action potentials.

    Science.gov (United States)

    Ogura, Taku; Shikata, Hideto; Hase, Hitoshi; Mori, Masaki; Hayashida, Taturo; Osawa, Toru; Mikami, Yasuo; Kubo, Toshikazu

    2003-10-01

    Transcutaneous electrical stimulation applied to the vertebral column produces compound muscle action potentials (CMAPs) from the leg muscles. Using this method, we evaluated the efferent pathways of the lumbosacral nerve roots. The subjects were 26 healthy volunteers and 31 patients with lumbar disc herniation (LDH). CMAP recordings were obtained from the bilateral vastus medialis, tibialis anterior, extensor digitorum brevis, and abductor hallucis muscles using low-output-impedance stimulation. In normal subjects, the CMAP latency increased linearly with the distance between the stimulating electrode and the recording electrode, with little difference in latency between the left and the right sides in each subject. The CMAP amplitude was significantly lower in the patients with LDH, and the latency was also prolonged when the stimulating electrode was placed above the lesion. This technique may thus be a useful noninvasive method for assessing lumbosacral nerve root function in patients with LDH.

  8. Variation of the Surface of the Longissimus Dorsi (LD Muscle and the Section of the Leg of Mutton at Young Sheep of Different Breed Structures

    Directory of Open Access Journals (Sweden)

    Elena Ilişiu

    2010-10-01

    Full Text Available The research was done on carcasses from the slaughter of young male sheep intensively fattened belonging to the local Tsigai race of mountain ecotype and its half-breeds with Suffolk and German blackface (GCCN. The purpose of the research was to determine Logissimus dorsi (LD and leg of moutton area, because these parts provide information on Ist meat quality. Research results have noted that lots of half-breeds achieved higher Longissimus dorsi (LD and leg of moutton area, compared with the pure breed batch. Compared with Tsigai breed, Longissimus dorsi (LD area deterrmined was higher with 10,75% to Suffolk x Tsigai half-breeds, and 0,07% respectively to German Blackface x Tsigai half-breeds. Leg of moutton area was higher with 17,27% to Suffolk x Tsigai halfbreeds, and 2,75% respectively to German Blackface x Tsigai half-breeds. Research carried out special information on Ist meat quality on carcass.

  9. Leg oxygen uptake in the initial phase of intense exercise is slowed by a marked reduction in oxygen delivery

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Nyberg, Michael Permin; Mortensen, Stefan Peter

    2013-01-01

    -extensor exercise (60±3 W) for 4 min in a control setting (CON) and with arterial infusion of L-NMMA and indomethacin in the working leg to reduce blood flow by inhibiting formation of nitric oxide and prostanoids (double blockade; DB). In DB leg blood flow (LBF) and oxygen delivery during the first minute...

  10. Muscle Power Is an Independent Determinant of Pain and Quality of Life in Knee Osteoarthritis.

    Science.gov (United States)

    Reid, Kieran F; Price, Lori Lyn; Harvey, William F; Driban, Jeffrey B; Hau, Cynthia; Fielding, Roger A; Wang, Chenchen

    2015-12-01

    This study examined the relationships between leg muscle strength, power, and perceived disease severity in subjects with knee osteoarthritis (OA) in order to determine whether dynamic leg extensor muscle power would be associated with pain and quality of life in knee OA. Baseline data on 190 subjects with knee OA (mean ± SD age 60.2 ± 10.4 years, body mass index 32.7 ± 7.2 kg/m(2) ) were obtained from a randomized controlled trial. Knee pain was measured using the Western Ontario and McMaster Universities Osteoarthritis Index, and health-related quality of life was assessed using the Short Form 36 (SF-36). One-repetition maximum (1RM) strength was assessed using the bilateral leg press, and peak muscle power was measured during 5 maximum voluntary velocity repetitions at 40% and 70% of 1RM. In univariate analysis, greater muscle power was significantly associated with pain (r = -0.17, P power was a significant independent predictor of pain (P ≤ 0.05) and PCS scores (P ≤ 0.04). However, muscle strength was not an independent determinant of pain or quality of life (P ≥ 0.06). Muscle power is an independent determinant of pain and quality of life in knee OA. Compared to strength, muscle power may be a more clinically important measure of muscle function within this population. New trials to systematically examine the impact of muscle power training interventions on disease severity in knee OA are particularly warranted. © 2015, American College of Rheumatology.

  11. 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

  12. 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.

  13. 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

  14. Effects of graded exercise-induced dehydration and rehydration on circulatory markers of oxidative stress across the resting and exercising human leg.

    Science.gov (United States)

    Laitano, Orlando; Kalsi, Kameljit Kaur; Pearson, James; Lotlikar, Makra; Reischak-Oliveira, Alvaro; González-Alonso, José

    2012-05-01

    Exercise in the heat enhances oxidative stress markers in the human circulation, but the contribution of active skeletal muscle and the influence of hydration status remain unknown. To address this question, we measured leg exchange of glutathione (GSH), glutathione disulfide (GSSG), superoxide dismutase activity (SOD) and isoprostanes in seven males at rest and during submaximal one-legged knee extensor exercise in the following four conditions: (1) control euhydration (0% reduction in body mass), (2) mild-dehydration (2%), (3) moderate-dehydration (3.5%), (4) rehydration (0%). In all resting and control exercise conditions, a net GSH uptake was observed across the leg. In contrast, a significant leg release of GSH into the circulation (-354 ± 221 μmol/min, P exercise with moderate-dehydration, which was still present following full rehydration (-206 ± 122 μmol/min, P exercise, mild and moderate-dehydration decreased both femoral venous erythrocyte SOD activity (195 ± 6 vs. 180 ± 5 U/L, P release GSH into the circulation under moderate dehydration and subsequent rehydration, possibly to enhance the antioxidant defense.

  15. 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

  16. Corticospinal excitability changes following prolonged muscle tendon vibration

    NARCIS (Netherlands)

    Steyvers, M.; Levin, O.; Baelen, M.G.M. van; Swinnen, S.P.

    2003-01-01

    The present experiment addressed the time course of corticospinal excitability changes following interventional muscle tendon vibration. Using transcranial magnetic stimulation, motor evoked potentials of the flexor carpi radialis and extensor carpi radialis brevis muscle were recorded for a period

  17. Calprotectin is released from human skeletal muscle tissue during exercise

    DEFF Research Database (Denmark)

    Mortensen, Ole Hartvig; Andersen, Kasper; Fischer, Christian

    2008-01-01

    Skeletal muscle has been identified as a secretory organ. We hypothesized that IL-6, a cytokine secreted from skeletal muscle during exercise, could induce production of other secreted factors in skeletal muscle. IL-6 was infused for 3 h into healthy young males (n = 7) and muscle biopsies obtained...... in skeletal muscle following IL-6 infusion compared to controls. Furthermore, S100A8 and S100A9 mRNA levels were up-regulated 5-fold in human skeletal muscle following cycle ergometer exercise for 3 h at approximately 60% of in young healthy males (n = 8). S100A8 and S100A9 form calprotectin, which is known...... as an acute phase reactant. Plasma calprotectin increased 5-fold following acute cycle ergometer exercise in humans, but not following IL-6 infusion. To identify the source of calprotectin, healthy males (n = 7) performed two-legged dynamic knee extensor exercise for 3 h with a work load of approximately 50...

  18. MUSCLE ACTIVITY RESPONSE TO EXTERNAL MOMENT DURING SINGLE-LEG DROP LANDING IN YOUNG BASKETBALL PLAYERS: THE IMPORTANCE OF BICEPS FEMORIS IN REDUCING INTERNAL ROTATION OF KNEE DURING LANDING

    Directory of Open Access Journals (Sweden)

    Meguru Fujii

    2012-06-01

    Full Text Available Internal tibial rotation with the knee close to full extension combined with valgus collapse during drop landing generally results in non-contact anterior cruciate ligament (ACL injury. The purpose of this study was to investigate the relationship between internal rotation of the knee and muscle activity from internal and external rotator muscles, and between the internal rotation of knee and externally applied loads on the knee during landing in collegiate basketball players. Our hypothesis was that the activity of biceps femoris muscle would be an important factor reducing internal knee rotation during landing. The subjects were 10 collegiate basketball students: 5 females and 5 males. The subjects performed a single-leg drop landing from a 25-cm height. Femoral and tibial kinematics were measured using a 3D optoelectronic tracking system during the drop landings, and then the knee angular motions were determined. Ground reaction forces and muscle activation patterns (lateral hamstring and medial hamstring were simultaneously measured and computed. Results indicated that lower peak internal tibial rotation angle at the time of landing was associated with greater lateral hamstring activity (r = -0.623, p < 0.001. When gender was considered, the statistically significant correlation remained only in females. There was no association between the peak internal tibial rotation angle and the knee internal rotation moment. Control of muscle activity in the lateral to medial hamstring would be an important factor in generating sufficient force to inhibit excessive internal rotation during landing. Strengthening the biceps femoris might mitigate the higher incidence of non-contact ACL injury in female athletes

  19. Knee extensor strength and body weight in adolescent men and the risk of knee osteoarthritis by middle age

    DEFF Research Database (Denmark)

    Turkiewicz, Aleksandra; Timpka, Simon; Thorlund, Jonas Bloch

    2017-01-01

    be attributed to knee injury and adult occupation. CONCLUSION: Higher knee extensor strength in adolescent men was associated with increased risk of knee OA by middle age, challenging the current tenet of low muscle strength being a risk factor for OA. We confirmed higher weight to be a strong risk factor......OBJECTIVES: To assess the extent to which knee extensor strength and weight in adolescence are associated with knee osteoarthritis (OA) by middle age. METHODS: We studied a cohort of 40 121 men who at age 18 years in 1969/1970 underwent mandatory conscription in Sweden. We retrieved data...

  20. Wpływ prądów TENS średniej częstotliwości na czynność bioelektyczną mięśni prostowników nadgarstka = The influence of mid-frequency TENS currents on bioelectrical activity of the wrist extensor muscles

    Directory of Open Access Journals (Sweden)

    Grzegorz Srokowski

    2015-09-01

    wrist extensor muscle and ulnaris showed a decrease in firing rate of bioelectric muscle under the influence of currents of medium frequency TENS. This study allows for an objective document activity involved in muscle movement during functional activities. 2. Kinesiology EMG allows for quick and effective action possible to verify TENS currents during the rehabilitation procedure, it is an effective therapeutic method.   Key words: electrostimulation, TENS, EMG.

  1. 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.

  2. Surgery-induced changes and early recovery of hip-muscle strength, leg-press power, and functional performance after fast-track total hip arthroplasty

    DEFF Research Database (Denmark)

    Holm, Bente; Thorborg, Kristian; Husted, Henrik

    2013-01-01

    By measuring very early changes in muscle strength and functional performance after fast-track total hip arthroplasty (THA), post-operative rehabilitation, introduced soon after surgery, can be designed to specifically target identified deficits.......By measuring very early changes in muscle strength and functional performance after fast-track total hip arthroplasty (THA), post-operative rehabilitation, introduced soon after surgery, can be designed to specifically target identified deficits....

  3. [Insertion of gluteus maximus tendo-chilles lengthening with Z-shaped for the treatment of severe gluteal muscle contracture].

    Science.gov (United States)

    Chen, Huan-shi; Yang, Xiao-long

    2015-06-01

    To investigate clinical curative effects of gluteal muscle contracture release combined with insertion of gluteus maximus tendo-chilles lengthening with Z-shaped in treating severe gluteal muscles contracture. From 2006 May to 2011 May, 20 patients (35 sides) with severe gluteal muscle contracture were collected, including 12 males and 8 females, aged from 8 to 34 years old with an average of 13 years old; the courses of disease ranged from 3 to 21 years. All patients manifested abnormal gait at different degree, knees close together cannot squat,positive syndrome of Ober, positive test of alice leg. Gluteus contracture fascia release were performed firstly in operation, then insertion of tendo-chilles lengthening with Z-shaped were carried out. Preoperative and postoperative gait, and knee flexion hip extensor squat test, cross leg test, adduction and internal rotary activity of hip joint, stretch strength and motor ability after hip abduction were observed and compared. Twenty patients were followed up for 1 to 5 years. Gluteus maximus were released thoroughly, and snapping hip was disappeared, Ober syndrome were negative. There was significant differences in knee flexion hip extensor squat test, adduction and internal rotary activity of hip joint,stretch before and after operation (Pmuscle strength was protected,stretch strength and motor ability of hip joint were recovered well. Among them,31 cases got excellent results and 4 good. For severe gluteal muscles contracture,insertion of gluteus maximus tendo-chilles lengthening with Z-shaped performed after gluteus contracture fascia release could release gluteal muscle contracture to the greatest extent and obtain postoperative curative effect without resection of normal hip muscle fibers and destroy joint capsule.

  4. Propulsion phase of the single leg triple hop test in women with patellofemoral pain syndrome: a biomechanical study.

    Directory of Open Access Journals (Sweden)

    Andre Serra Bley

    Full Text Available Asymmetry in the alignment of the lower limbs during weight-bearing activities is associated with patellofemoral pain syndrome (PFPS, caused by an increase in patellofemoral (PF joint stress. High neuromuscular demands are placed on the lower limb during the propulsion phase of the single leg triple hop test (SLTHT, which may influence biomechanical behavior. The aim of the present cross-sectional study was to compare kinematic, kinetic and muscle activity in the trunk and lower limb during propulsion in the SLTHT using women with PFPS and pain free controls. The following measurements were made using 20 women with PFPS and 20 controls during propulsion in the SLTHT: kinematics of the trunk, pelvis, hip, and knee; kinetics of the hip, knee and ankle; and muscle activation of the gluteus maximus (GM, gluteus medius (GMed, biceps femoris (BF and vastus lateralis (VL. Differences between groups were calculated using three separate sets of multivariate analysis of variance for kinematics, kinetics, and electromyographic data. Women with PFPS exhibited ipsilateral trunk lean; greater trunk flexion; greater contralateral pelvic drop; greater hip adduction and internal rotation; greater ankle pronation; greater internal hip abductor and ankle supinator moments; lower internal hip, knee and ankle extensor moments; and greater GM, GMed, BL, and VL muscle activity. The results of the present study are related to abnormal movement patterns in women with PFPS. We speculated that these findings constitute strategies to control a deficient dynamic alignment of the trunk and lower limb and to avoid PF pain. However, the greater BF and VL activity and the extensor pattern found for the hip, knee, and ankle of women with PFPS may contribute to increased PF stress.

  5. Propulsion phase of the single leg triple hop test in women with patellofemoral pain syndrome: a biomechanical study.

    Science.gov (United States)

    Bley, Andre Serra; Correa, João Carlos Ferrari; Dos Reis, Amir Curcio; Rabelo, Nayra Deise Dos Anjos; Marchetti, Paulo Henrique; Lucareli, Paulo Roberto Garcia

    2014-01-01

    Asymmetry in the alignment of the lower limbs during weight-bearing activities is associated with patellofemoral pain syndrome (PFPS), caused by an increase in patellofemoral (PF) joint stress. High neuromuscular demands are placed on the lower limb during the propulsion phase of the single leg triple hop test (SLTHT), which may influence biomechanical behavior. The aim of the present cross-sectional study was to compare kinematic, kinetic and muscle activity in the trunk and lower limb during propulsion in the SLTHT using women with PFPS and pain free controls. The following measurements were made using 20 women with PFPS and 20 controls during propulsion in the SLTHT: kinematics of the trunk, pelvis, hip, and knee; kinetics of the hip, knee and ankle; and muscle activation of the gluteus maximus (GM), gluteus medius (GMed), biceps femoris (BF) and vastus lateralis (VL). Differences between groups were calculated using three separate sets of multivariate analysis of variance for kinematics, kinetics, and electromyographic data. Women with PFPS exhibited ipsilateral trunk lean; greater trunk flexion; greater contralateral pelvic drop; greater hip adduction and internal rotation; greater ankle pronation; greater internal hip abductor and ankle supinator moments; lower internal hip, knee and ankle extensor moments; and greater GM, GMed, BL, and VL muscle activity. The results of the present study are related to abnormal movement patterns in women with PFPS. We speculated that these findings constitute strategies to control a deficient dynamic alignment of the trunk and lower limb and to avoid PF pain. However, the greater BF and VL activity and the extensor pattern found for the hip, knee, and ankle of women with PFPS may contribute to increased PF stress.

  6. Open extensor tendon injuries: an epidemiologic study.

    Science.gov (United States)

    Patillo, Dominic; Rayan, Ghazi M

    2012-01-01

    To report the epidemiology, mechanism, anatomical location, distribution, and severity of open extensor tendon injuries in the digits, hand, and forearm as well as the frequency of associated injuries to surrounding bone and soft tissue. Retrospective chart review was conducted for patients who had operative repair of open digital extensor tendon injuries in all zones within an 11-year period. Data was grouped according to patient characteristics, zone of injury, mechanism of injury, and presence of associated injury. Statistical analysis was used to determine the presence of relevant associations. Eighty-six patients with 125 severed tendons and 105 injured digits were available for chart reviews. Patients were predominantly males (83%) with a mean age of 34.2 years and the dominant extremity was most often injured (60%). The thumb was the most commonly injured (25.7%), followed by middle finger (24.8), whereas small finger was least affected (10.5%). Sharp laceration was the most common mechanism of injury (60%), and most of these occurred at or proximal to the metacarpophalangeal joints. Most saw injuries occurred distal to the metacarpophalangeal joint. Zone V was the most commonly affected in the fingers (27%) while zone VT was the most commonly affected in the thumb (69%). Associated injuries to bone and soft tissue occurred in 46.7% of all injuries with saw and crush/avulsions being predictive of fractures and damage to the underlying joint capsule. The extensor mechanism is anatomically complex, and open injuries to the dorsum of the hand, wrist, and forearm, especially of crushing nature and those inflicted by saws, must be thoroughly evaluated. Associated injuries should be ruled out in order to customize surgical treatment and optimize outcome.

  7. A Morphometric Analysis of Fibularis Tertius Muscle in Eastern Indian Population

    Directory of Open Access Journals (Sweden)

    Gyanaranjan Nayak

    2017-10-01

    Full Text Available Introduction: Fibularis tertius is a unipennate muscle of extensor compartment of leg exclusively found in humans. Fibularis tertius muscle flap is used for transposition and correcting any laxity in the ankle joint by foot surgeons. Variable insertion of the muscle may play a role in causation of torsional stress as observed in certain fractures of foot. Aim: To study the incidence of fibularis tertius muscle with its dimensions and note the variations in origin and insertion of the muscle in cadaveric limbs. Materials and Methods: Hundred cadaveric lower limbs (50 right and 50 left were dissected and analysed macroscopically to find out the incidence, dimensions and variations in origin and insertion of the fibularis tertius muscle. Results: Fibularis tertius was present in all the limbs. It was inserted to fourth or fifth metatarsals. The length and width of the muscle and its tendon were also noted. Conclusion: Distal attachment of fibularis tertius is variable making a precise knowledge of the muscle necessary for foot surgeons in performing tendoplasty or tendon transfer surgeries.

  8. Alpha adrenergic receptor blockade increases capillarisation and fractional O2 extraction and lowers blood flow in contracting human skeletal muscle

    DEFF Research Database (Denmark)

    Mortensen, Stefan P; Egginton, Stuart; Madsen, Mads

    2017-01-01

    AIM: To investigate the effect of elevated basal shear stress on angiogenesis in humans, and the role of enhanced skeletal muscle capillarisation on blood flow and O2 extraction. METHODS: Limb haemodynamics and O2 extraction was measured at rest and during one-leg knee-extensor exercise (12 and 24W......) in 10 healthy untrained young men before and after 4 weeks treatment with an α1 receptor-antagonist (Terazosin, 1-2 mg day(-1) ). Corresponding biopsies were taken from the m. vastus lateralis. RESULTS: Resting leg blood flow was increased by 57% 6 hours following Terazosin treatment (P... basal capillary-to-fibre ratio was 1.69±0.08 and increased to 1.90±0.08 after treatment (Pblood flow and venous lactate levels lower (6-7%; P

  9. Effects of aging and exercise training on leg hemodynamics and oxidative metabolism in the transition from rest to steady state exercise

    DEFF Research Database (Denmark)

    Piil, Peter Bergmann; Jørgensen, Tue Smith; Egelund, Jon

    2018-01-01

    hemodynamics and oxidative metabolism in the transition from rest to steady state exercise engaging the knee-extensor muscles in young (n=15, 25{plus minus}1 years) and older (n=15, 72{plus minus}1 years) subjects before and after a period of aerobic high-intensity exercise training. To enhance cGMP signaling....... The rate of increase in leg VO2 was, however, similar in the two groups as a result of higher ( PGMP signaling did not affect the rate of increase in blood flow or VO2 in either group. Exercise training augmented ( P.... A lower blood flow response in aging does not appear to be a result of reduced cGMP signaling....

  10. Quantifying Leg Movement Activity During Sleep.

    Science.gov (United States)

    Ferri, Raffaele; Fulda, Stephany

    2016-12-01

    Currently, 2 sets of similar rules for recording and scoring leg movement (LM) exist, including periodic LM during sleep (PLMS) and periodic LM during wakefulness. The former were published in 2006 by a task force of the International Restless Legs Syndrome Study Group, and the second in 2007 by the American Academy of Sleep Medicine. This article reviews the basic recording methods, scoring rules, and computer-based programs for PLMS. Less frequent LM activities, such as alternating leg muscle activation, hypnagogic foot tremor, high-frequency LMs, and excessive fragmentary myoclonus are briefly described. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Tuberculosis tenosynovitis of the extensor tendons of the wrist

    OpenAIRE

    Mrabet, Dalila; Ouenniche, Kmar; Mizouni, Habiba; Ounaies, Mouna; Khémiri, Chékib; Sahli, Héla; Sellami, Slaheddine

    2011-01-01

    Mycobacterial tuberculous tenosynovitis of the extensor tendon sheath is an extremely rare manifestation of extrapulmonary tuberculosis. The diagnosis may be easily delayed because of its non-specific clinical signs. We report a new case of tuberculous tenosynovitis of the extensor without concomitant pulmonary tuberculosis or documented immunodeficiency.

  12. Muscle oxygenation of vastus lateralis and medialis muscles during alternating and pulsed current electrical stimulation.

    Science.gov (United States)

    Aldayel, Abdulaziz; Muthalib, Makii; Jubeau, Marc; McGuigan, Michael; Nosaka, Kazunori

    2011-05-01

    This study compared between alternating and pulsed current electrical muscle stimulation (EMS) for muscle oxygenation and blood volume during isometric contractions. Nine healthy men (23-48 years) received alternating current EMS (2500 Hz) modulated at 75 Hz on the knee extensors of one leg, and pulsed current EMS (75 Hz) for the other leg separated by 2 weeks in a randomised, counter-balanced order. Pulse duration (400 μs), on-off ratio (5-15 s) and other stimulation parameters were matched between conditions and 30 isometric contractions were induced at the knee joint angle of 100° (0° full extension). Changes in tissue oxygenation index (∆TOI) and total hemoglobin volume (∆tHb) of vastus lateralis and medialis muscles over 30 contractions were assessed by a near-infrared spectroscopy, and were compared between conditions by a two-way repeated measures ANOVA. Peak torque produced during EMS increased over 30 contractions in response to the increase in the stimulation intensity for pulsed current, but not for the alternating current EMS. The torque during each isometric contraction was less stable in alternating than pulsed current EMS. The changes in ∆TOI amplitude during relaxation phases and ∆tHb amplitude were not significantly different between conditions. However, the decreases in ∆TOI amplitude during contraction phases from baseline were significantly (P < 0.05) greater for the pulsed current than alternating current from the 18th contraction (-15.6 ± 2.3 vs. -8.9 ± 1.8%) to 30th contraction (-10.7 ± 1.8 vs. -4.8 ± 1.5%). These results suggest that the muscles were less activated in the alternating current EMS when compared with the pulsed current EMS.

  13. Individual Muscle use in Hamstring Exercises by Soccer Players Assessed using Functional MRI.

    Science.gov (United States)

    Fernandez-Gonzalo, R; Tesch, P A; Linnehan, R M; Kreider, R B; Di Salvo, V; Suarez-Arrones, L; Alomar, X; Mendez-Villanueva, A; Rodas, G

    2016-06-01

    This study used functional magnetic resonance imaging (fMRI) to compare individual muscle use in exercises aimed at preventing hamstring injuries. Thirty-six professional soccer players were randomized into 4 groups, each performing either Nordic hamstring, flywheel leg curl, Russian belt or conic-pulley exercise. MRIs were performed before and immediately after a bout of 4 sets of 8 repetitions. Pre-post exercise differences in contrast shift (T2) were analyzed for the long (BFLh) and short head (BFSh) of biceps femoris, semitendinosus (ST), semimembranosus (SM) and gracilis (GR) muscles. Flywheel leg curl increased (Phamstring, GR (39%), ST (16%) and BFSh (14%) showed increased T2 (Phamstring and GR muscle use. However, no single exercise executed was able to increase T2 of all hamstring and synergist muscles analyzed. It is therefore suggested that multiple exercises must be carried out to bring in, and fully activate all knee flexors and hip extensors. © Georg Thieme Verlag KG Stuttgart · New York.

  14. Immobilization increases interleukin-6, but not tumour necrosis factor-a, release from the leg during exercise in humans

    DEFF Research Database (Denmark)

    Reihmane, Dace; Hansen, Andreas Vigelsø; Jensen, Martin Gram

    2013-01-01

    have now studied the temporal relationship of leg IL-6 and TNF-a release before and during isolated two-legged exercise after 14 days of one-leg immobilization (IM) while the other leg served as the control (CON) leg. Fifteen healthy male subjects (mean ± SEM age, 23 ± 1 years; body mass index, 23.......6 ± 0.7 kg m; and maximal oxygen uptake, 46.8 ± 1.4 ml kg min) performed 45 min of two-legged dynamic knee-extensor exercise at 19.6 ± 0.8 W. Arterial and femoral venous blood samples from the CON and the IM leg were collected every 15 min during exercise, and leg blood flow was measured with Doppler...

  15. Kinaesthetic ipsilateral and crossed extensor plantar response: A new way to elicit upgoing toe sign (Babinski response?

    Directory of Open Access Journals (Sweden)

    Abraham Kuruvilla

    2011-01-01

    Full Text Available We describe a phenomenon of "kinaesthetic extensor plantar response" in advanced pyramidal dysfunction, an interesting observation noted in a patient with dorsal myelopathy. A 44-year-old woman presented with one-year history of gradually progressive weakness and stiffness of both lower limbs along with urge incontinence of urine. Examination showed spontaneous elicitation of extensor plantar response while assessing the tone by rolling method as well as on noxious stimulation of the thigh. Magnetic resonance imaging (MRI of the dorsal spine and digital subtraction angiography showed the presence of spinal dural arteriovenous fistula causing myelopathy. This case exemplifies the fact that in advanced pyramidal dysfunction, not only the receptive field of Babinski reflex may extend to the leg or thigh, but may also integrate with other modalities of stimulation, such as the rolling movement. The possible underlying pathophysiology of such a phenomenon is discussed.

  16. 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.

  17. Leg Injuries and Disorders

    Science.gov (United States)

    ... are important for motion and standing. Playing sports, running, falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint dislocations, and fractures. ...

  18. Knee extensor strength and body weight in adolescent men and the risk of knee osteoarthritis by middle age.

    Science.gov (United States)

    Turkiewicz, Aleksandra; Timpka, Simon; Thorlund, Jonas Bloch; Ageberg, Eva; Englund, Martin

    2017-10-01

    To assess the extent to which knee extensor strength and weight in adolescence are associated with knee osteoarthritis (OA) by middle age. We studied a cohort of 40 121 men who at age 18 years in 1969/1970 underwent mandatory conscription in Sweden. We retrieved data on isometric knee extensor strength, weight, height, smoking, alcohol consumption, parental education and adult occupation from Swedish registries. We identified participants diagnosed with knee OA or knee injury from 1987 to 2010 through the National Patient Register. We estimated the HR of knee OA using multivariable-adjusted Cox proportional regression model. To assess the influence of adult knee injury and occupation, we performed a formal mediation analysis. The mean (SD) knee extensor strength was 234 (47) Nm, the mean (SD) weight was 66 (9.3) kg. During 24 years (median) of follow-up starting at the age of 35 years, 2049 persons were diagnosed with knee OA. The adjusted HR (95% CI) of incident knee OA was 1.12 (1.06 to 1.18) for each SD of knee extensor strength and 1.18 (1.15 to 1.21) per 5 kg of body weight. Fifteen per cent of the increase in OA risk due to higher knee extensor strength could be attributed to knee injury and adult occupation. Higher knee extensor strength in adolescent men was associated with increased risk of knee OA by middle age, challenging the current tenet of low muscle strength being a risk factor for OA. We confirmed higher weight to be a strong risk factor for knee OA. © 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.

  19. The effect of targeted exercise on knee-muscle function in patients with persistent hamstring deficiency following ACL reconstruction

    DEFF Research Database (Denmark)

    Bregenhof, Bo; Jørgensen, Uffe; Aagaard, Per

    2018-01-01

    BACKGROUND: Anterior cruciate ligament (ACL) reconstruction, using hamstring auto-graft is a common surgical procedure, which often leads to persistent hamstring muscle-strength deficiency and reduced function. The purpose of this randomized controlled trial (RCT) is to investigate the effect...... at 12-24 months' post surgery, will be recruited through outpatient clinics and advertisements. Patients will be randomized to a 12-week progressive, strength and neuromuscular exercise group (SNG) with supervised training twice weekly or a control intervention (CON) consisting of a home-based, low......-intensity exercise program. Outcome measures include between-group change in maximal isometric knee-flexor strength (primary outcome) and knee-extensor muscle strength, hamstring-to-quadriceps strength ratios of the leg that has been operated on and Knee injury and Osteoarthritis Outcome Score (KOOS) (secondary...

  20. Associations between measures of gait stability, leg strength and fear of falling

    NARCIS (Netherlands)

    Toebes, M.J.P.; Hoozemans, M.J.M.; Dekker, J.; van Dieen, J.H.

    2015-01-01

    Fear of falling (FoF) in elderly frequently leads to decreased quality of life. FoF is suggested to be associated with changes in gait quality and muscle strength with aging. The aim of this study was to determine whether gait quality and maximal voluntary torque (MVT) of knee extensor muscles are

  1. Partial body weight support treadmill training speed influences paretic and non-paretic leg muscle activation, stride characteristics, and ratings of perceived exertion during acute stroke rehabilitation.

    Science.gov (United States)

    Burnfield, Judith M; Buster, Thad W; Goldman, Amy J; Corbridge, Laura M; Harper-Hanigan, Kellee

    2016-06-01

    Intensive task-specific training is promoted as one approach for facilitating neural plastic brain changes and associated motor behavior gains following neurologic injury. Partial body weight support treadmill training (PBWSTT), is one task-specific approach frequently used to improve walking during the acute period of stroke recovery (training parameters and physiologic demands during this early recovery phase. To examine the impact of four walking speeds on stride characteristics, lower extremity muscle demands (both paretic and non-paretic), Borg ratings of perceived exertion (RPE), and blood pressure. A prospective, repeated measures design was used. Ten inpatients post unilateral stroke participated. Following three familiarization sessions, participants engaged in PBWSTT at four predetermined speeds (0.5, 1.0, 1.5 and 2.0mph) while bilateral electromyographic and stride characteristic data were recorded. RPE was evaluated immediately following each trial. Stride length, cadence, and paretic single limb support increased with faster walking speeds (p⩽0.001), while non-paretic single limb support remained nearly constant. Faster walking resulted in greater peak and mean muscle activation in the paretic medial hamstrings, vastus lateralis and medial gastrocnemius, and non-paretic medial gastrocnemius (p⩽0.001). RPE also was greatest at the fastest compared to two slowest speeds (ptraining at the slowest speeds. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Per meal dose and frequency of protein consumption is associated with lean mass and muscle performance.

    Science.gov (United States)

    Loenneke, Jeremy P; Loprinzi, Paul D; Murphy, Caoileann H; Phillips, Stuart M

    2016-12-01

    It has been hypothesized that for older adults evenly distributing consumption of protein at 30-40 g per meal throughout the day may result in more favorable retention of lean mass and muscular strength. Such a thesis has not, to our knowledge, been tested outside of short-term studies or acute measures of muscle protein synthesis. To examine whether the number of times an individual consumed a minimum of 30 g of protein at a meal is associated with leg lean mass and knee extensor strength. Data from the 1999-2002 NHANES were used, with 1081 adults (50-85 y) constituting the analytic sample. A "multiple pass" 24-h dietary interview format was used to collect detailed information about the participants' dietary intake. Knee extensor strength was assessed objectively using the Kin Com MP dynamometer. Leg lean mass was estimated from whole-body dual-energy X-ray absorptiometry (DXA) scans. Participants with 1 vs. 0 (β adjusted  = 23.6, p = 0.002) and 2 vs. 0 (β adjusted  = 51.1, p = 0.001) meals of ≥30 g protein/meal had greater strength and leg lean mass (1 vs. 0, β adjusted  = 1160, p frequency with leg lean mass and strength plateaued at ∼45 g protein/meal for those consuming 2 vs. 0 meals above the evaluated protein/meal threshold. However, for those with only 1 meal at or above the evaluated threshold, the response plateaued at 30 g/meal. Leg lean mass mediated the relationship between protein frequency and strength, with the proportion of the total effect mediated being 64%. We found that more frequent consumption of meals containing between 30 and 45 g protein/meal produced the greatest association with leg lean mass and strength. Thus, the consumption of 1-2 daily meals with protein content from 30 to 45 g may be an important strategy for increasing and/or maintaining lean body mass and muscle strength with aging. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  3. Muscular activity and torque of the foot dorsiflexor muscles during decremental isometric test: A cross-sectional study.

    Science.gov (United States)

    Ruiz-Muñoz, Maria; González-Sánchez, Manuel; Martín-Martín, Jaime; Cuesta-Vargas, Antonio I

    2017-06-01

    To analyse the torque variation level that could be explained by the muscle activation (EMG) amplitude of the three major foot dorsiflexor muscles (tibialis anterior (TA), extensor digitorum longus (EDL), extensor hallucis longus (EHL)) during isometric foot dorsiflexion at different intensities. In a cross-sectional study, forty-one subjects performed foot dorsiflexion at 100%, 75%, 50% and 25% of maximal voluntary contractions (MVC) with the hip and knee flexed 90° and the ankle in neutral position (90° between leg and foot). Three foot dorsiflexions were performed for each intensity. Outcome variables were: maximum (100% MVC) and relative torque (75%, 50%, 25% MVC), maximum and relative EMG amplitude. A linear regression analysis was calculated for each intensity of the isometric foot dorsiflexion. The degree of torque variation (dependent variable) from the independent variables explain (EMG amplitude of the three major foot dorsiflexor muscles) the increases when the foot dorsiflexion intensity is increased, with values of R 2 that range from 0.194 (during 25% MVC) to 0.753 (during 100% MVC). The reliability of the outcome variables was excellent. The EMG amplitude of the three main foot dorsiflexors exhibited more variance in the dependent variable (torque) when foot dorsiflexion intensity increases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Leg vascular and skeletal muscle mitochondrial adaptations to aerobic high-intensity exercise training are enhanced in the early postmenopausal phase

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Egelund, Jon; Mandrup Jensen, Camilla Maria

    2017-01-01

    the haemodynamic response to acute exercise in matched pre- and postmenopausal women before and after 12 weeks of aerobic high intensity exercise training. Twenty premenopausal and 16 early postmenopausal (3.1 ± 0.5 [mean ± SEM] years after final menstrual period) women only separated by 4 (50 ± 0 versus 54 ± 1...... receptor α (ERRα) were increased (P training in the postmenopausal women whereas only the levels of mitochondrial complex V, eNOS, and COX-2 were increased (P aerobic......Exercise training leads to favourable adaptations within skeletal muscle; however, this effect of exercise training may be blunted in postmenopausal women due to the loss of oestrogens. Furthermore, postmenopausal women may have an impaired vascular response to acute exercise. We examined...

  5. Foot, leg, and ankle swelling

    Science.gov (United States)

    Swelling of the ankles - feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... Foot, leg, and ankle swelling is common when the person also: Is overweight Has a blood clot in the leg Is older Has ...

  6. Isometric muscle strength and mobility capacity in children with cerebral palsy.

    Science.gov (United States)

    Dallmeijer, Annet J; Rameckers, Eugene A; Houdijk, Han; de Groot, Sonja; Scholtes, Vanessa A; Becher, Jules G

    2017-01-01

    To determine the relationship between isometric leg muscle strength and mobility capacity in children with cerebral palsy (CP) compared to typically developing (TD) peers. Participants were 62 children with CP (6-13 years), able to walk with (n = 10) or without (n = 52) walking aids, and 47 TD children. Isometric muscle strength of five muscle groups of the leg was measured using hand-held dynamometry. Mobility capacity was assessed with the 1-min walk, the 10-m walk, sit-to-stand, lateral-step-up and timed-stair tests. Isometric strength of children with CP was reduced to 36-82% of TD. When adjusted for age and height, the percentage of variance in mobility capacity that was explained by isometric strength of the leg muscles was 21-24% (walking speed), 25% (sit-to-stand), 28% (lateral-step-up) and 35% (timed-stair) in children with CP. Hip abductors and knee flexors had the largest contribution to the explained variance, while knee extensors showed the weakest correlation. Weak or no associations were found between strength and mobility capacity in TD children. Isometric strength, especially hip abductor and knee flexor strength, is moderately related to mobility capacity in children with CP, but not in TD children. To what extent training of these muscle groups will lead to better mobility capacity needs further study. Implications for Rehabilitation Strength training in children with cerebral palsy (CP) may be targeted more specifically at hip abductors and knee flexors. The moderate associations imply that large improvements in mobility capacity may not be expected when strength increases.

  7. EFFECTS OF CONCENTRIC AND ECCENTRIC MUSCLE ACTIONS ON SERUM MYOSTATIN AND FOLLISTATIN-LIKE RELATED GENE LEVELS

    Directory of Open Access Journals (Sweden)

    Lemuel Taylor

    2004-12-01

    Full Text Available The present study determined the effects of concentric and eccentric muscle actions on the contents of serum myostatin and follistatin-like related gene (FLRG. Eight untrained males performed one exercise bout with each leg, separated by three weeks. One bout consisted of 7 sets of 10 repetitions of eccentric muscle actions of the knee extensors at 150% of the concentric 1-RM while the other bout consisted of 7 sets of 10 repetitions of concentric muscle actions at 75% 1-RM. The legs used and the bouts performed were randomized. Five days prior to each exercise bout, baseline measurements were taken for muscle strength. For both bouts, a venous blood sample was obtained immediately prior to exercise and again at 6, 24, and 48 hr post-exercise. Data were analyzed with 2 X 4 (bout x test ANOVA (p < 0.05. Increases in serum myostatin and FLRG occurred with each exercise bout and, excluding 48 hr post-exercise, were significantly correlated to one another (p < 0.05. After eccentric exercise, peak increases of 68% and 50% (p < 0.05 were observed for myostatin and FLRG, respectively. Similar increases of 54% and 44% (p < 0.05 were observed after concentric muscle actions. There was no significant difference in expression of myostatin or FLRG as a function of muscle action type. Our results suggest that a single bout of exercise with either eccentric or concentric muscle actions appear to elicit a similar increase in serum myostatin and FLRG. Therefore, the type of muscle action may not be as much a mitigating factor for increasing serum myostatin and FLRG rather than the muscle action per se.

  8. An automatic hinge system for leg orthoses

    NARCIS (Netherlands)

    Rietman, J. S.; Goudsmit, J.; Meulemans, D.; Halbertsma, J. P. K.; Geertzen, J. H. B.

    2004-01-01

    This paper describes a new automatic hinge system for leg orthoses, which provides knee stability in stance, and allows knee-flexion during swing. Indications for the hinge system are a paresis or paralysis of the quadriceps muscles. Instrumented gait analysis was performed in three patients, fitted

  9. An automatic hinge system for leg orthoses

    NARCIS (Netherlands)

    Rietman, J.S.; Goudsmit, J.; Meulemans, D.; Halbertsma, J.P.K.; Geertzen, J.H.B.

    This paper describes a new, automatic hinge system for leg orthoses, which provides knee stability in stance, and allows knee-flexion during swing. Indications for the hinge system are a paresis or paralysis of the quadriceps muscles. Instrumented gait analysis was performed in three patients,

  10. X-Ray Exam: Femur (Upper Leg)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Femur (Upper Leg) KidsHealth / For Parents / X- ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

  11. Effects of Balance Training on Postural Sway, Leg Extensor Strength, and Jumping Height in Adolescents

    Science.gov (United States)

    Granacher, Urs; Gollhofer, Albert; Kriemler, Susi

    2010-01-01

    Deficits in strength of the lower extremities and postural control have been associated with a high risk of sustaining sport-related injuries. Such injuries often occur during physical education (PE) classes and mostly affect the lower extremities. Thus, the objectives of this study were to investigate the effects of balance training on postural…

  12. Isolated Tuberculous Tenosynovitis of the Anterior Tibial and Extensor Digitorum Longus Tendons

    Directory of Open Access Journals (Sweden)

    Berhan Genç

    2013-01-01

    Full Text Available Musculoskeletal system is involved in 1-5% of extrapulmonary cases of tuberculosis. Tuberculous tenosynovitis is a rare form of musculoskeletal tuberculosis. Tuberculosis of the tendon sheath in the hand has been seen in a few cases. Involvement of the tendons of the leg is less common. Diagnosis is not easy as there are no specific clinical symptoms or signs. A 33-year-old male presented with painful swelling in the distal right lower limb that caused restriction of movement. Imaging studies showed inflammation and infection of the extensor digitorium longus and tibialis anterior tendons. Histopathological studies showed a necrotizing granulomatous inflammation in the synovial tissue. A diagnosis of tuberculosis was made and medical treatment was initiated that proved successful. Patient remained infection-free at 26-month follow-up examination.

  13. Stimulated echo diffusion tensor imaging and SPAIR T2 -weighted imaging in chronic exertional compartment syndrome of the lower leg muscles.

    Science.gov (United States)

    Sigmund, Eric E; Sui, Dabang; Ukpebor, Obehi; Baete, Steven; Fieremans, Els; Babb, James S; Mechlin, Michael; Liu, Kecheng; Kwon, Jane; McGorty, KellyAnne; Hodnett, Philip A; Bencardino, Jenny

    2013-11-01

    To evaluate the performance of diffusion tensor imaging (DTI) in the evaluation of chronic exertional compartment syndrome (CECS) as compared to T2 -weighted (T2w) imaging. Using an Institutional Review Board (IRB)-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant protocol, spectral adiabatic inversion recovery (SPAIR) T2w imaging and stimulated echo DTI were applied to eight healthy volunteers and 14 suspected CECS patients before and after exertion. Longitudinal and transverse diffusion eigenvalues, mean diffusivity (MD), and fractional anisotropy (FA) were measured in seven calf muscle compartments, which in patients were classified by their response on T2w: normal (20% change). Mixed model analysis of variance compared subject groups and compartments in terms of response factors (post/pre-exercise ratios) of DTI parameters. All diffusivities significantly increased (P DTI shows promise as an ancillary imaging method in the diagnosis and understanding of the pathophysiology in CECS. Future studies may explore its utility in predicting response to treatment. Copyright © 2013 Wiley Periodicals, Inc.

  14. Reliability and Validity of a New Method for Isometric Back Extensor Strength Evaluation Using A Hand-Held Dynamometer.

    Science.gov (United States)

    Park, Hee-Won; Baek, Sora; Kim, Hong Young; Park, Jung-Gyoo; Kang, Eun Kyoung

    2017-10-01

    To investigate the reliability and validity of a new method for isometric back extensor strength measurement using a portable dynamometer. A chair equipped with a small portable dynamometer was designed (Power Track II Commander Muscle Tester). A total of 15 men (mean age, 34.8±7.5 years) and 15 women (mean age, 33.1±5.5 years) with no current back problems or previous history of back surgery were recruited. Subjects were asked to push the back of the chair while seated, and their isometric back extensor strength was measured by the portable dynamometer. Test-retest reliability was assessed with intraclass correlation coefficient (ICC). For the validity assessment, isometric back extensor strength of all subjects was measured by a widely used physical performance evaluation instrument, BTE PrimusRS system. The limit of agreement (LoA) from the Bland-Altman plot was evaluated between two methods. The test-retest reliability was excellent (ICC=0.82; 95% confidence interval, 0.65-0.91). The Bland-Altman plots demonstrated acceptable agreement between the two methods: the lower 95% LoA was -63.1 N and the upper 95% LoA was 61.1 N. This study shows that isometric back extensor strength measurement using a portable dynamometer has good reliability and validity.

  15. V1 and v2b interneurons secure the alternating flexor-extensor motor activity mice require for limbed locomotion.

    Science.gov (United States)

    Zhang, Jingming; Lanuza, Guillermo M; Britz, Olivier; Wang, Zhi; Siembab, Valerie C; Zhang, Ying; Velasquez, Tomoko; Alvarez, Francisco J; Frank, Eric; Goulding, Martyn

    2014-04-02

    Reciprocal activation of flexor and extensor muscles constitutes the fundamental mechanism that tetrapod vertebrates use for locomotion and limb-driven reflex behaviors. This aspect of motor coordination is controlled by inhibitory neurons in the spinal cord; however, the identity of the spinal interneurons that serve this function is not known. Here, we show that the production of an alternating flexor-extensor motor rhythm depends on the composite activities of two classes of ventrally located inhibitory neurons, V1 and V2b interneurons (INs). Abrogating V1 and V2b IN-derived neurotransmission in the isolated spinal cord results in a synchronous pattern of L2 flexor-related and L5 extensor-related locomotor activity. Mice lacking V1 and V2b inhibition are unable to articulate their limb joints and display marked deficits in limb-driven reflex movements. Taken together, these findings identify V1- and V2b-derived neurons as the core interneuronal components of the limb central pattern generator (CPG) that coordinate flexor-extensor motor activity. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Association between muscle strength and metabolic syndrome in older Korean men and women: the Korean Longitudinal Study on Health and Aging.

    Science.gov (United States)

    Yang, Eun Joo; Lim, Soo; Lim, Jae-Young; Kim, Ki Woong; Jang, Hak Chul; Paik, Nam-Jong

    2012-03-01

    The objective of the study was to investigate the association between metabolic syndrome (MS) and muscle strength in community-dwelling older men and women in Korea. Korean men and women 65 years and older living in a single, typical South Korean city (n = 647) were enrolled in the Korean Longitudinal Study on Health and Aging study. The diagnosis of MS was evaluated according to the definition of the National Cholesterol Education Program Adult Treatment Panel III. Isokinetic muscle strength of the knee extensors, as determined by peak torque per body weight (newton meter per kilogram) and hand-grip strength per body weight (newton per kilogram), was measured. Participants without MS had greater leg muscle strength and grip strength per weight. The effect of MS on muscle strength was more prominent in men than in women in our study population. Only men showed a significant interaction between MS and age for muscle strength (P = .014), and the effect was greater in men aged 65 to 74 years compared with those older than 75 years (119.2 ± 31.2 vs 134.5 ± 24.3 N m/kg). Participants with MS had weaker knee extensor strength after controlling the covariates (β = -90.80, P = .003), and the interaction term (age × MS × male sex) was significant (β = 1.00, P = .017). Metabolic syndrome is associated with muscle weakness, and this relationship is particularly pronounced in men. Age can modify the impact of MS on muscle strength. Men aged 65 to 74 years with MS need a thorough assessment of muscle strength to prevent disability. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Changes in muscle cross-sectional area, muscle force, and jump performance during 6 weeks of progressive whole-body vibration combined with progressive, high intensity resistance training

    Science.gov (United States)

    Rosenberger, A.; Beijer, Å.; Johannes, B.; Schoenau, E.; Mester, J.; Rittweger, J.; Zange, J.

    2017-01-01

    Objectives: We hypothesized that progressive whole-body vibration (WBV) superimposed to progressive high intensity resistance training has greater effects on muscle cross-sectional area (CSA), muscle force of leg muscles, and jump performance than progressive high intensity resistance training alone. Methods: Two groups of healthy male subjects performed either 6 weeks of Resistive Vibration Exercise (RVE, squats and heel raises with WBV, n=13) or Resistive Exercise (RE, squats and heel raises without WBV, n=13). Squats under RVE required indispensable weight loading on the forefoot to damp harmful vibrations to the head. Time, intervention, and interaction effects were analyzed. Results: After 6 weeks of training, knee extensor CSA, isometric knee extension force, and counter movement jump height increased equally in both groups (time effect, P<0.001, P≤0.02, and P≤0.03, respectively), whereas only in RVE ankle plantar flexor CSA and isometric ankle plantar flexion force reached significance or a tendency, respectively, (time effect, P=0.015 and P=0.069, respectively; intervention effect also for the latter, P=0.006). Drop jump contact time did significantly more improve in RVE (interaction effect, P=0.042). Conclusions: RVE showed better training effects than RE only in plantar flexor muscles. RVE seems to be suitable in professional sports with a special focus on calf muscles. PMID:28574410

  18. Multiple muscle tear after fall on buttock-role of conservative management and exercise for early recovery and return to play.

    Science.gov (United States)

    Adhau, Rajesh; Angrish, Piyush; Ahuja, Ashok; Sandhu, Avtar Singh

    2014-04-01

    to describe role of alternative management as an approach to management and rehabilitation of multiple hip muscles tears by the use of 1 RM (Repetition Maximum) testing and hip muscle strengthening program along with the use of sports specific drills for rehabilitation and recovery. There is very limited literature describing multiple hip muscle tears and the conservative management of the same. 1RM testing and strengthening of hip muscles is an approach that is able to help in the return to sports of an athlete without surgical intervention. the patient, is a 21-year-old male hockey player who presented with pain right buttock, right lower leg and a limp on the right side while walking. Physical examination revealed a positive Trendelenburg sign both in stance and gait phase. Hip rotational movements showed a normal range of motion, there was a severe pain in the right buttock on movements which he described at 8/10 on VAS (Visual Analogue Scale). Strength assessment revealed weakness of the right hip flexors and extensors and also of the abductor and external hip rotator muscles. Treatment protocol followed was based on 1 RM testing of muscles and hip strengthening exercises and sports specific drills. following the intervention, the patient reported pain at 0/10 VAS while doing all activities and also showed good muscle control with no limp. this highlights an alternative protocol for treating multiple hip muscle tears and illustrates the importance of 1 RM testing as a part of examination and sports medicine intervention.

  19. 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.

  20. Sex Differences in Neuromuscular Fatigability of the Knee Extensors Post-Stroke

    Directory of Open Access Journals (Sweden)

    Meghan Kirking

    2017-01-01

    Full Text Available Background and Purpose: Despite the implications of optimizing strength training post-stroke, little is known about the differences in fatigability between men and women with chronic stroke. The purpose of this study was to determine the sex differences in knee extensor muscle fatigability and potential mechanisms in individuals with stroke. Methods: Eighteen participants (10 men, eight women with chronic stroke (≥6 months and 23 (12 men, 11 women nonstroke controls participated in the study. Participants performed an intermittent isometric contraction task (6 s contraction, 3 s rest at 30% of maximal voluntary contraction (MVC torque until failure to maintain the target torque. Electromyography was used to determine muscle activation and contractile properties were assessed with electrical stimulation of the quadriceps muscles. Results: Individuals with stroke had a briefer task duration (greater fatigability than nonstroke individuals (24.1 ± 17 min vs. 34.9 ± 16 min. Men were more fatigable than women for both nonstroke controls and individuals with stroke (17.9 ± 9 min vs. 41.6 ± 15 min. Individuals with stroke had less fatigue-related changes in muscle contractile properties and women with stroke differed in their muscle activation strategy during the fatiguing contractions. Conclusions: Men and women fatigue differently post-stroke and this may be due to the way they neurally activate muscle groups.

  1. Low muscle glycogen and elevated plasma free fatty acid modify but do not prevent exercise-induced PDH activation in human skeletal muscle

    DEFF Research Database (Denmark)

    Kiilerich, Kristian; Gudmundsson, Mikkel; Birk, Jesper Bratz

    2010-01-01

    to the contra-lateral leg (CON) the day before the experiment day. On the experimental days, plasma FFA was ensured normal or remained elevated by consuming breakfast rich (low FFA) or poor (high FFA) in carbohydrate, 2 hours before performing 20 min of two-legged knee extensor exercise. Vastus lateralis...

  2. Effects of low-level laser therapy applied before or after plyometric exercise on muscle damage markers: randomized, double-blind, placebo-controlled trial.

    Science.gov (United States)

    Fritsch, Carolina Gassen; Dornelles, Maurício Pinto; Severo-Silveira, Lucas; Marques, Vanessa Bernardes; Rosso, Isabele de Albuquerque; Baroni, Bruno Manfredini

    2016-12-01

    Promising effects of phototherapy on markers of exercise-induced muscle damage has been already demonstrated in constant load or isokinetic protocols. However, its effects on more functional situations, such as plyometric exercises, and when is the best moment to apply this treatment (pre- or post-exercise) remain unclear. Therefore, the purpose of this study was to investigate the effect of low-level laser therapy (LLLT) before or after plyometric exercise on quadriceps muscle damage markers. A randomized, double-blinded, placebo-controlled trial was conducted with 24 healthy men, 12 at pre-exercise treatment group and 12 at post-exercise treatment group. Placebo and LLLT (810 nm, 200 mW per diode, 6 J per diode, 240 J per leg) were randomly applied on right/left knee extensor muscles of each volunteer before/after a plyometric exercise protocol. Muscular echo intensity (ultrasonography images), soreness (visual analogue scale - VAS), and strength impairment (maximal voluntary contraction - MVC) were assessed at baseline, 24, 48, and 72 h post-exercise. Legs treated with LLLT before or after exercise presented significantly smaller increments of echo intensity (values up to 1 %) compared to placebo treatments (increased up to ∼7 %). No significant treatment effect was found for VAS and MVC, although a trend toward better results on LLLT legs have been found for VAS (mean values up to 30 % lesser than placebo leg). In conclusion, LLLT applied before or after plyometric exercise reduces the muscle echo intensity response and possibly attenuates the muscle soreness. However, these positive results were not observed on strength impairment.

  3. Lower extremity muscle functions during full squats.

    Science.gov (United States)

    Robertson, D G E; Wilson, Jean-Marie J; St Pierre, Taunya A

    2008-11-01

    The purpose of this research was to determine the functions of the gluteus maximus, biceps femoris, semitendinosus, rectus femoris, vastus lateralis, soleus, gastrocnemius, and tibialis anterior muscles about their associated joints during full (deep-knee) squats. Muscle function was determined from joint kinematics, inverse dynamics, electromyography, and muscle length changes. The subjects were six experienced, male weight lifters. Analyses revealed that the prime movers during ascent were the monoarticular gluteus maximus and vasti muscles (as exemplified by vastus lateralis) and to a lesser extent the soleus muscles. The biarticular muscles functioned mainly as stabilizers of the ankle, knee, and hip joints by working eccentrically to control descent or transferring energy among the segments during scent. During the ascent phase, the hip extensor moments of force produced the largest powers followed by the ankle plantar flexors and then the knee extensors. The hip and knee extensors provided the initial bursts of power during ascent with the ankle extensors and especially a second burst from the hip extensors adding power during the latter half of the ascent.

  4. Pictorial essay: Ultrasonography in 'tennis leg'.

    Science.gov (United States)

    Shah, Jeshil R; Shah, Bipin R; Shah, Ankit B

    2010-11-01

    Tennis leg is caused by a rupture of the medial head of the gastrocnemius muscle, usually at its distal musculotendinous junction region. However, tears in this muscle and its tendon are also included under the term 'tennis leg'. It is seen regularly in practice and is an important cause of a painful calf. The common USG findings include: disruption of the pinnate pattern of the distal medial gastrocnemius, usually near the junction of the triceps surae (which is the echogenic line between the gastrocnemius, the soleus, and the plantaris muscles), fluid tracking along the fascia, adjacent hematoma, and intramuscular tears as well as hematomas. USG is useful for confirming the diagnosis, excluding other causes of a painful calf, for assessing the severity of the disease, and in follow-up.

  5. Customizing Extensor Reconstruction in Vascularized Toe Joint Transfers to Finger Proximal Interphalangeal Joints: A Strategic Approach for Correcting Extensor Lag.

    Science.gov (United States)

    Loh, Charles Yuen Yung; Hsu, Chung-Chen; Lin, Cheng-Hung; Chen, Shih-Heng; Lien, Shwu-Huei; Lin, Chih-Hung; Wei, Fu-Chan; Lin, Yu-Te

    2017-04-01

    Vascularized toe proximal interphalangeal joint transfer allows the restoration of damaged joints. However, extensor lag and poor arc of motion have been reported. The authors present their outcomes of treatment according to a novel reconstructive algorithm that addresses extensor lag and allows for consistent results postoperatively. Vascularized toe joint transfers were performed in a consecutive series of 26 digits in 25 patients. The average age was 30.5 years, with 14 right and 12 left hands. Reconstructed digits included eight index, 10 middle, and eight ring fingers. Simultaneous extensor reconstructions were performed and eight were centralization of lateral bands, five were direct extensor digitorum longus-to-extensor digitorum communis repairs, and 13 were central slip reconstructions. The average length of follow-up was 16.7 months. The average extension lag was 17.9 degrees. The arc of motion was 57.7 degrees (81.7 percent functional use of pretransfer toe proximal interphalangeal joint arc of motion). There was no significant difference in the reconstructed proximal interphalangeal joint arc of motion for the handedness (p = 0.23), recipient digits (p = 0.37), or surgical experience in vascularized toe joint transfer (p = 0.25). The outcomes of different techniques of extensor mechanism reconstruction were similar in terms of extensor lag, arc of motion, and reconstructed finger arc of motion compared with the pretransfer toe proximal interphalangeal joint arc of motion. With this treatment algorithm, consistent outcomes can be produced with minimal extensor lag and maximum use of potential toe proximal interphalangeal joint arc of motion. Therapeutic, IV.

  6. 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

  7. Modulation of recurrent inhibition from knee extensors to ankle motoneurones during human walking

    DEFF Research Database (Denmark)

    Lamy, Jean-Charles; Iglesias, Caroline; Lackmy, Alexandra

    2008-01-01

    The neural control for muscle coordination during human locomotion involves spinal and supraspinal networks, but little is known about the exact mechanisms implicated. The present study focused on modulation of heteronymous recurrent inhibition from knee extensors to ankle motoneurones at different...... times in the gait cycle, when quadriceps (Quad) muscle activity overlaps that in tibialis anterior (TA) and soleus (Sol). The effects of femoral nerve stimulation on ankle motoneurones were investigated during treadmill walking and during tonic co-contraction of Quad and TA/Sol while standing. Recurrent...... inhibition of TA motoneurones depended on the level of background EMG, and was similar during walking and standing for matched background EMG levels. On the other hand, recurrent inhibition in Sol was reduced in early stance, with respect to standing, and enhanced in late stance. Reduced inhibition in Sol...

  8. Walking on high heels changes muscle activity and the dynamics of human walking significantly

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Svendsen, Morten Bo Søndergaard; Nørreslet, Andreas

    2012-01-01

    The aim of the study was to investigate the distribution of net joint moments in the lower extremities during walking on high-heeled shoes compared with barefooted walking at identical speed. Fourteen female subjects walked at 4 km/h across three force platforms while they were filmed by five...... digital video cameras operating at 50 frames/second. Both barefooted walking and walking on high-heeled shoes (heel height: 9 cm) were recorded. Net joint moments were calculated by 3D inverse dynamics. EMG was recorded from eight leg muscles. The knee extensor moment peak in the first half of the stance...... phase was doubled when walking on high heels. The knee joint angle showed that high-heeled walking caused the subjects to flex the knee joint significantly more in the first half of the stance phase. In the frontal plane a significant increase was observed in the knee joint abductor moment and the hip...

  9. Effects of wearing lower leg compression sleeves on locomotion economy.

    Science.gov (United States)

    Kurz, Eduard; Anders, Christoph

    2018-09-01

    The purpose of this investigation was to assess the effect of compression sleeves on muscle activation cost during locomotion. Twenty-two recreationally active men (age: 25 ± 3 years) ran on a treadmill at four different speeds (ordered sequence of 2.8, 3.3, 2.2, and 3.9 m/s). The tests were performed without (control situation, CON) and while wearing specially designed lower leg compression sleeves (SL). Myoelectric activity of five lower leg muscles (tibialis anterior, fibularis longus, lateral and medial head of gastrocnemius, and soleus) was captured using Surface EMG. To assess muscle activation cost, the cumulative muscle activity per distance travelled (CMAPD) of the CON and SL situations was determined. Repeated measures analyses of variance were performed separately for each muscle. The analyses revealed a reduced lower leg muscle activation cost with respect to test situation for SL for all muscles (p  0.18). The respective significant reductions of CMAPD values during SL ranged between 4% and 16% and were largest at 2.8 m/s. The findings presented point towards an improved muscle activation cost while wearing lower leg compression sleeves during locomotion that have potential to postpone muscle fatigue.

  10. Fatigue and muscle-tendon stiffness after stretch-shortening cycle and isometric exercise.

    Science.gov (United States)

    Toumi, Hechmi; Poumarat, Georges; Best, Thomas M; Martin, Alain; Fairclough, John; Benjamin, Mike

    2006-10-01

    The purpose of the present study was to compare vertical jump performance after 2 different fatigue protocols. In the first protocol, subjects performed consecutive sets of 10 repetitions of stretch-shortening cycle (SSC) contractions. In the second protocol, successive sets of 10 repetitions of isometric contractions were performed for 10 s with the knee at 90 degrees of flexion. The exercises were stopped when the subjects failed to reach 50% of their maximum voluntary isometric contractions. Maximal isometric force and maximal concentric power were assessed by performing supine leg presses, squat jumps, and drop jumps. Surface EMG was used to determine changes in muscle activation before and after fatigue. In both groups, the fatigue exercises reduced voluntary isometric force, maximal concentric power, and drop jump performance. Kinematic data showed a decrease in knee muscle-tendon stiffness accompanied by a lengthened ground contact time. EMG analysis showed that the squat and drop jumps were performed similarly before and after the fatigue exercise for both groups. Although it was expected that the stiffness would decrease more after SSC than after isometric fatigue (as a result of a greater alteration of the reflex sensitivity SSC), our results showed that both protocols had a similar effect on knee muscle stiffness during jumping exercises. Both fatigue protocols induced muscle fatigue, and the decrease in jump performance was linked to a decrease in the strength and stiffness of the knee extensor muscles.

  11. Are the hamstrings from the drive leg or landing leg more active in baseball pitchers? An electromyographic study.

    Science.gov (United States)

    Erickson, Brandon J; Zaferiou, Antonia; Chalmers, Peter N; Ruby, Deana; Malloy, Phillip; Luchetti, Timothy J; Verma, Nikhil N; Romeo, Anthony A

    2017-11-01

    Ulnar collateral ligament reconstruction (UCLR) has become a common procedure among baseball players of all levels. There are several graft choices in performing UCLR, one of which is a hamstring (gracilis or semitendinosus) autograft. It is unclear whether the hamstring muscle from a pitcher's drive leg (ipsilateral side of the UCLR) or landing leg (contralateral side of the UCLR) is more active during the pitching motion. We hypothesized that the landing leg semitendinosus will be more electromyographically active than the drive leg. Healthy, elite male pitchers aged 16-21 years were recruited. Sixteen pitchers (average age, 17.6 ± 1.6 years; 67% threw right handed) underwent electromyographic analysis. Pitchers threw 5 fastballs at 100% effort from the wind-up with electromyographic analysis of every pitch. Activation of the semitendinosus and biceps femoris in both legs was compared within pitchers and between pitchers. Hamstring activity was higher in the drive leg than in the landing leg during each phase and in sum, although the difference was significant only during the double support phase (P = .021). On within-pitcher analysis, 10 of 16 pitchers had significantly more sum hamstring activity in the drive leg than in the landing leg, while only 4 of 16 had more activity in the landing leg (P = .043). During the baseball pitch, muscle activity of the semitendinosus was higher in the drive leg than in the landing leg in most pitchers. Surgeons performing UCLR using hamstring autograft should consider harvesting the graft from the pitcher's landing leg to minimize disruption to the athlete's pitching motion. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  12. Congenital hypertrophy of multiple intrinsic muscles of the foot.

    Science.gov (United States)

    Shiraishi, Tomohiro; Park, Susam; Niu, Atushi; Hasegawa, Hiromi

    2014-12-01

    Congenital hypertrophy of a single intrinsic muscle of the foot is rare, and as far as we know, only six cases have been reported. We describe a case of congenital anomaly that showed hypertrophy of multiple intrinsic muscles of the foot; the affected muscles were all the intrinsic muscles of the foot except the extensor digitorum brevis or extensor hallucis. Other tissues such as adipose tissue, nervous tissue, or osseous tissue showed no abnormalities. To reduce the volume of the foot we removed parts of the enlarged muscles.

  13. Work-related pain in extrinsic finger extensor musculature of instrumentalists is associated with intracellular pH compartmentation during exercise.

    Directory of Open Access Journals (Sweden)

    Angel Moreno-Torres

    Full Text Available BACKGROUND: Although non-specific pain in the upper limb muscles of workers engaged in mild repetitive tasks is a common occupational health problem, much is unknown about the associated structural and biochemical changes. In this study, we compared the muscle energy metabolism of the extrinsic finger extensor musculature in instrumentalists suffering from work-related pain with that of healthy control instrumentalists using non-invasive phosphorus magnetic resonance spectroscopy ((31P-MRS. We hypothesize that the affected muscles will show alterations related with an impaired energy metabolism. METHODOLOGY/PRINCIPAL FINDINGS: We studied 19 volunteer instrumentalists (11 subjects with work-related pain affecting the extrinsic finger extensor musculature and 8 healthy controls. We used (31P-MRS to find deviations from the expected metabolic response to exercise in phosphocreatine (PCr, inorganic phosphate (Pi, Pi/PCr ratio and intracellular pH kinetics. We observed a reduced finger extensor exercise tolerance in instrumentalists with myalgia, an intracellular pH compartmentation in the form of neutral and acid compartments, as detected by Pi peak splitting in (31P-MRS spectra, predominantly in myalgic muscles, and a strong association of this pattern with the condition. CONCLUSIONS/SIGNIFICANCE: Work-related pain in the finger extrinsic extensor muscles is associated with intracellular pH compartmentation during exercise, non-invasively detectable by (31P-MRS and consistent with the simultaneous energy production by oxidative metabolism and glycolysis. We speculate that a deficit in energy production by oxidative pathways may exist in the affected muscles. Two possible explanations for this would be the partial and/or local reduction of blood supply and the reduction of the muscle oxidative capacity itself.

  14. Work-Related Pain in Extrinsic Finger Extensor Musculature of Instrumentalists Is Associated with Intracellular pH Compartmentation during Exercise

    Science.gov (United States)

    Moreno-Torres, Angel; Rosset-Llobet, Jaume; Pujol, Jesus; Fàbregas, Sílvia; Gonzalez-de-Suso, Jose-Manuel

    2010-01-01

    Background Although non-specific pain in the upper limb muscles of workers engaged in mild repetitive tasks is a common occupational health problem, much is unknown about the associated structural and biochemical changes. In this study, we compared the muscle energy metabolism of the extrinsic finger extensor musculature in instrumentalists suffering from work-related pain with that of healthy control instrumentalists using non-invasive phosphorus magnetic resonance spectroscopy (31P-MRS). We hypothesize that the affected muscles will show alterations related with an impaired energy metabolism. Methodology/Principal Findings We studied 19 volunteer instrumentalists (11 subjects with work-related pain affecting the extrinsic finger extensor musculature and 8 healthy controls). We used 31P-MRS to find deviations from the expected metabolic response to exercise in phosphocreatine (PCr), inorganic phosphate (Pi), Pi/PCr ratio and intracellular pH kinetics. We observed a reduced finger extensor exercise tolerance in instrumentalists with myalgia, an intracellular pH compartmentation in the form of neutral and acid compartments, as detected by Pi peak splitting in 31P-MRS spectra, predominantly in myalgic muscles, and a strong association of this pattern with the condition. Conclusions/Significance Work-related pain in the finger extrinsic extensor muscles is associated with intracellular pH compartmentation during exercise, non-invasively detectable by 31P-MRS and consistent with the simultaneous energy production by oxidative metabolism and glycolysis. We speculate that a deficit in energy production by oxidative pathways may exist in the affected muscles. Two possible explanations for this would be the partial and/or local reduction of blood supply and the reduction of the muscle oxidative capacity itself. PMID:20161738

  15. Effects of whole-body cryotherapy (-110 °C) on proprioception and indices of muscle damage.

    Science.gov (United States)

    Costello, J T; Algar, L A; Donnelly, A E

    2012-04-01

    The purpose of this study was to investigate the effects of whole-body cryotherapy (WBC) on proprioceptive function, muscle force recovery following eccentric muscle contractions and tympanic temperature (T(TY) ). Thirty-six subjects were randomly assigned to a group receiving two 3-min treatments of -110 ± 3 °C or 15 ± 3 °C. Knee joint position sense (JPS), maximal voluntary isometric contraction (MVIC) of the knee extensors, force proprioception and T(TY) were recorded before, immediately after the exposure and again 15 min later. A convenience sample of 18 subjects also underwent an eccentric exercise protocol on their contralateral left leg 24 h before exposure. MVIC (left knee), peak power output (PPO) during a repeated sprint on a cycle ergometer and muscles soreness were measured pre-, 24, 48 and 72h post-treatment. WBC reduced T(TY) , by 0.3 °C, when compared with the control group (P<0.001). However, JPS, MVIC or force proprioception was not affected. Similarly, WBC did not effect MVIC, PPO or muscle soreness following eccentric exercise. WBC, administered 24 h after eccentric exercise, is ineffective in alleviating muscle soreness or enhancing muscle force recovery. The results of this study also indicate no increased risk of proprioceptive-related injury following WBC. © 2011 John Wiley & Sons A/S.

  16. A single bout of whole-leg, peristaltic pulse external pneumatic compression upregulates PGC-1α mRNA and endothelial nitric oxide sythase protein in human skeletal muscle tissue.

    Science.gov (United States)

    Kephart, Wesley C; Mobley, C Brooks; Fox, Carlton D; Pascoe, David D; Sefton, JoEllen M; Wilson, Trent J; Goodlett, Michael D; Kavazis, Andreas N; Roberts, Michael D; Martin, Jeffrey S

    2015-07-01

    What is the central question of this study? Does 60 min of peristaltic pulse external pneumatic compression (EPC) alter gene and protein expression patterns related to metabolism, vascular biology, redox balance and inflammation in vastus lateralis biopsy samples? What is the main finding and its importance? A single bout of EPC transiently upregulates PGC-1α mRNA, while also upregulating endothelial nitric oxide synthase protein and nitric oxide metabolite concentrations in vastus lateralis biopsy samples. We investigated whether a single 60 min bout of whole-leg, lower pressure external pneumatic compression (EPC) altered select vascular, metabolic, antioxidant and inflammation-related mRNAs. Ten participants (eight male, two female; aged 22.0 ± 0.4 years) reported to the laboratory 4 h postprandial, and vastus lateralis muscle biopsies were obtained before (PRE) and 1 and 4 h after EPC treatment. Messenger RNA expression was analysed using real-time RT-PCR, and significant mRNA findings were investigated further by Western blot analysis of respective protein concentrations. Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) mRNA increased by 77% 1 h following EPC compared with PRE levels (P = 0.005), but no change in protein concentration 1 or 4 h post-EPC was observed. Increases in endothelial nitric oxide sythase (eNOS) mRNA (+44%) and superoxide dismutase 2 (SOD2) mRNA (+57%) 1 h post-EPC as well as an increase in interleukin-10 mRNA (+132%) 4 h post-EPC compared with PRE levels were observed, but only approached significance (P = 0.076, 0.077 and 0.074, respectively). Interestingly, eNOS protein (+40%, P = 0.025) and nitrate and nitrite (NOx) concentrations (+69%, P = 0.025) increased 1-4 h post-EPC. Moreover, SOD2 protein tended to increase from PRE to 4 h post-EPC (+43%, P = 0.074), although no changes in tissue 4-hydroxnonenal levels was observed. An acute bout of EPC transiently upregulates PGC-1α mRNA, while also upregulating e

  17. Lyden-af-Leg

    DEFF Research Database (Denmark)

    Toft, Herdis

    Præsentation af seniorforsker-projekt Lyden-af-Leg i et traderingsperspektiv og med indledende fokus på YouTube som traderings-platform.......Præsentation af seniorforsker-projekt Lyden-af-Leg i et traderingsperspektiv og med indledende fokus på YouTube som traderings-platform....

  18. 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…

  19. Sonography findings in tears of the extensor pollicis longus tendon and correlation with CT, MRI and surgical findings

    International Nuclear Information System (INIS)

    Ruiz Santiago, Fernando; Garofano Plazas, Pilar; Fernandez, Juan Miguel Tristan

    2008-01-01

    We present our experience in the diagnosis of extensor pollicis longus tendon tears using different imaging methods. In the past 2 years, 12 patients (7 males, 5 females) with extension deficit of distal phalanx of thumb were diagnosed with extensor pollicis longus tendon (EPL) rupture by means of different imaging methods. The ultrasound pattern consisted of a gap between tendon stumps occupied by a continuous (eight cases) or discontinuous (four cases) attenuated hypoechoic string. In nine cases, the tendon ends were identified as a thickened stump-like structure. In the other three cases, tendon stumps were attenuated and mixed with atrophic muscle or wrist subcutaneous fat. All ultrasound findings were confirmed by CT, MR and/or surgical findings

  20. Degree of thoracic kyphosis and peak torque of trunk flexors and extensors among healthy women☆☆☆

    Science.gov (United States)

    Granito, Renata Neves; Aveiro, Mariana Chaves; Rennó, Ana Claudia Muniz; Oishi, Jorge; Driusso, Patricia

    2014-01-01

    Objective The aim of this study was to analyze the effects of aging on the degree of thoracic kyphosis and peak torque of the trunk flexor and extensor muscles among women without a densitometric diagnosis of osteoporosis. Methods Thirty women were selected to make up three groups: young women (n = 10; 24.60 ± 2.27 years of age); adults (n = 10; 43.50 ± 2.88); and elderly women (n = 10; 62.40 ± 2.67). Bone mineral density (BMD), degree of thoracic kyphosis and peak torque of the trunk flexors and extensors were evaluated. Differences between the groups were evaluated using the Kruskal–Wallis ANOVA and Mann–Whitney U tests. Pearson's correlation coefficient was used to assess correlations between the variables. The significance level was taken to be 5% (p ≤ 0.05). Results The elderly group presented a greater degree of thoracic kyphosis (p = 0.009) and lower peak torque of the trunk flexors and extensors than the young group. The adult group presented lower peak torque of the trunk than the young group. A negative correlation was observed between age and peak torque of the trunk flexors and extensors (p ≤ 0.001), and a positive correlation between age and the degree of thoracic kyphosis (r = 0.58; p ≤ 0.001). The elderly group presented higher values for the eccentric/concentric ratio of the peak torque for flexors (p = 0.03) and extensors (p = 0.02). Conclusion This study suggests that physiological aging may be associated with a greater degree of thoracic kyphosis and lower muscle strength of the trunk flexors and extensors. Moreover, the elderly women showed a relative capacity for preservation of eccentric strength. PMID:26229814

  1. The effect of knee extensor open kinetic chain resistance training in the ACL-injured knee.

    Science.gov (United States)

    Barcellona, Massimo G; Morrissey, Matthew C; Milligan, Peter; Clinton, Melissa; Amis, Andrew A

    2015-11-01

    To investigate the effect of different loads of knee extensor open kinetic chain resistance training on anterior knee laxity and function in the ACL-injured (ACLI) knee. Fifty-eight ACLI subjects were randomised to one of three (12-week duration) training groups. The STAND group trained according to a standardised rehabilitation protocol. Subjects in the LOW and HIGH group trained as did the STAND group but with the addition of seated knee extensor open kinetic chain resistance training at loads of 2 sets of 20 repetition maximum (RM) and 20 sets of 2RM, respectively. Anterior knee laxity and measurements of physical and subjective function were performed at baseline, 6 and 12 weeks. Thirty-six subjects were tested at both baseline and 12 weeks (STAND n = 13, LOW n = 11, HIGH n = 12). The LOW group demonstrated a reduction in 133 N anterior knee laxity between baseline and 12 weeks testing when compared to the HIGH and the STAND groups (p = 0.009). Specifically, the trained-untrained knee laxity decreased an average of approximately 5 mm in the LOW group while remaining the same in the other two groups. Twelve weeks of knee extensor open kinetic chain resistance training at loads of 2 sets of 20RM led to a reduction in anterior knee laxity in the ACLI knee. This reduction in laxity does not appear to offer any significant short-term functional advantages when compared to a standard rehabilitation protocol. These results indicate that knee laxity can be decreased with resistance training of the thigh muscles. Randomised controlled trial, Level II.

  2. Muscle performance following an acute bout of plyometric training combined with low or high intensity weight exercise.

    Science.gov (United States)

    Beneka, Anastasia G; Malliou, Paraskevi K; Missailidou, Victoria; Chatzinikolaou, Athanasios; Fatouros, Ioannis; Gourgoulis, Vassilios; Georgiadis, Elias

    2013-01-01

    To determine the time course of performance responses after an acute bout of plyometric exercise combined with high and low intensity weight training, a 3-group (including a control group), repeated-measures design was employed. Changes in performance were monitored through jumping ability by measuring countermovement and squat jumping, and strength performance assessment through isometric and isokinetic testing of knee extensors (at two different velocities). Participants in both experimental groups performed a plyometric protocol consisting of 50 jumps over 50 cm hurdles and 50 drop jumps from a 50 cm plyometric box. Additionally, each group performed two basic weight exercises consisting of leg presses and leg extensions at 90-95% of maximum muscle strength for the high intensity group and 60% of maximum muscle strength for the low intensity group. The results of the study suggest that an acute bout of intense plyometric exercise combined with weight exercise induces time-dependent changes in performance, which are also dependent on the nature of exercise protocol and testing procedures. In conclusion, acute plyometric exercise with weight exercise may induce a substantial decline in jumping performance for as long as 72 hours but not in other forms of muscle strength.

  3. Gene Expression Profiling in Slow-Type Calf Soleus Muscle of 30 Days Space-Flown Mice.

    Directory of Open Access Journals (Sweden)

    Guido Gambara

    Full Text Available Microgravity exposure as well as chronic disuse are two main causes of skeletal muscle atrophy in animals and humans. The antigravity calf soleus is a reference postural muscle to investigate the mechanism of disuse-induced maladaptation and plasticity of human and rodent (rats or mice skeletal musculature. Here, we report microgravity-induced global gene expression changes in space-flown mouse skeletal muscle and the identification of yet unknown disuse susceptible transcripts found in soleus (a mainly slow phenotype but not in extensor digitorum longus (a mainly fast phenotype dorsiflexor as functional counterpart to soleus. Adult C57Bl/N6 male mice (n = 5 flew aboard a biosatellite for 30 days on orbit (BION-M1 mission, 2013, a sex and age-matched cohort were housed in standard vivarium cages (n = 5, or in a replicate flight habitat as ground control (n = 5. Next to disuse atrophy signs (reduced size and myofiber phenotype I to II type shift as much as 680 differentially expressed genes were found in the space-flown soleus, and only 72 in extensor digitorum longus (only 24 genes in common compared to ground controls. Altered expression of gene transcripts matched key biological processes (contractile machinery, calcium homeostasis, muscle development, cell metabolism, inflammatory and oxidative stress response. Some transcripts (Fzd9, Casq2, Kcnma1, Ppara, Myf6 were further validated by quantitative real-time PCR (qRT-PCR. Besides previous reports on other leg muscle types we put forth for the first time a complete set of microgravity susceptible gene transcripts in soleus of mice as promising new biomarkers or targets for optimization of physical countermeasures and rehabilitation protocols to overcome disuse atrophy conditions in different clinical settings, rehabilitation and spaceflight.

  4. Electromyographic analyses of muscle pre-activation induced by single joint exercise.

    Science.gov (United States)

    Júnior, Valdinar A R; Bottaro, Martim; Pereira, Maria C C; Andrade, Marcelino M; P Júnior, Paulo R W; Carmo, Jake C

    2010-01-01

    To investigate whether performing a low-intensity, single-joint exercises for knee extensors was an efficient strategy for increasing the number of motor units recruited in the vastus lateralis muscle during a subsequent multi-joint exercises. Nine healthy male participants (23.33+/-3.46 yrs) underwent bouts of exercise in which knee extension and 45 degrees , and leg press exercises were performed in sequence. In the low-intensity bout (R30), 15 unilateral knee extensions were performed, followed by 15 repetitions of the leg presses at 30% and 60% of one maximum repetition load (1-MR), respectively. In the high-intensity bout (R60), the same sequence was performed, but the applied load was 60% of 1-MR for both exercises. A single set of 15 repetitions of the leg press at 60% of 1-MR was performed as a control exercise (CR). The surface electromyographic signals of the vastus lateralis muscle were recorded by means of a linear electrode array. The root mean square (RMS) values were determined for each repetition of the leg press, and linear regressions were calculated from these results. The slopes of the straight lines obtained were then normalized using the linear coefficients of the regression equations and compared using one-way ANOVAs for repeated measures. The slopes observed in the CR were significantly lower than those in the R30 and R60 (precruitment of motor units was more effective when a single-joint exercise preceded the multi-joint exercise. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number ACTRN12609000413224.

  5. Curcumin and Piperine Supplementation and Recovery Following Exercise Induced Muscle Damage: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Barthélémy Delecroix, Abd Elbasset Abaïdia, Cédric Leduc, Brian Dawson, Grégory Dupont

    2017-03-01

    Full Text Available The aim of this study was to analyze the effects of oral consumption of curcumin and piperine in combination on the recovery kinetics after exercise-induced muscle damage. Forty-eight hours before and following exercise-induced muscle damage, ten elite rugby players consumed curcumin and piperine (experimental condition or placebo. A randomized cross-over design was performed. Concentric and isometric peak torque for the knee extensors, one leg 6 seconds sprint performance on a non-motorized treadmill, counter movement jump performance, blood creatine kinase concentration and muscle soreness were assessed immediately after exercise, then at 24h, 48h and 72h post-exercise. There were moderate to large effects of the exercise on the concentric peak torque for the knee extensors (Effect size (ES = -1.12; Confidence interval at 90% (CI90%: -2.17 to -0.06, the one leg 6 seconds sprint performance (ES=-1.65; CI90% = -2.51to -0.80 and the counter movement jump performance (ES = -0.56; CI90% = -0.81 to -0.32 in the 48h following the exercise. There was also a large effect of the exercise on the creatine kinase level 72h after the exercise in the control group (ES = 3.61; CI90%: 0.24 to 6.98. This decrease in muscle function and this elevation in creatine kinase indicate that the exercise implemented was efficient to induce muscle damage. Twenty four hours post-exercise, the reduction (from baseline in sprint mean power output was moderately lower in the experimental condition (-1.77 ± 7.25%; 1277 ± 153W in comparison with the placebo condition (-13.6 ± 13.0%; 1130 ± 241W (Effect Size = -1.12; Confidence Interval 90%=-1.86 to -0.86. However, no other effect was found between the two conditions. Curcumin and piperine supplementation before and after exercise can attenuate some, but not all, aspects of muscle damage.

  6. The Motor and the Brake of the Trailing Leg in Human Walking: Leg Force Control Through Ankle Modulation and Knee Covariance

    Science.gov (United States)

    Toney, Megan E.; Chang, Young-Hui

    2016-01-01

    Human walking is a complex task, and we lack a complete understanding of how the neuromuscular system organizes its numerous muscles and joints to achieve consistent and efficient walking mechanics. Focused control of select influential task-level variables may simplify the higher-level control of steady state walking and reduce demand on the neuromuscular system. As trailing leg power generation and force application can affect the mechanical efficiency of step-to-step transitions, we investigated how joint torques are organized to control leg force and leg power during human walking. We tested whether timing of trailing leg force control corresponded with timing of peak leg power generation. We also applied a modified uncontrolled manifold analysis to test whether individual or coordinated joint torque strategies most contributed to leg force control. We found that leg force magnitude was adjusted from step-to-step to maintain consistent leg power generation. Leg force modulation was primarily determined by adjustments in the timing of peak ankle plantar-flexion torque, while knee torque was simultaneously covaried to dampen the effect of ankle torque on leg force. We propose a coordinated joint torque control strategy in which the trailing leg ankle acts as a motor to drive leg power production while trailing leg knee torque acts as a brake to refine leg power production. PMID:27334888

  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. Progressive Resistance Training and Cancer Testis (PROTRACT) - Efficacy of resistance training on muscle function, morphology and inflammatory profile in testicular cancer patients undergoing chemotherapy: design of a randomized controlled trial

    DEFF Research Database (Denmark)

    Christensen, Jesper F; Andersen, Jesper L; Adamsen, Lis

    2011-01-01

    of developing considerable long-term morbidity, including second malignant neoplasms, cardiovascular disease, and pulmonary toxicity. One neglected side effect is the significant muscular fatigue mentioned by many patients with testicular cancer both during and after treatment. Very limited information exists....... Primary outcome: mean fiber area and fiber type composition measured by histochemical analyses, satellite cells and levels of protein and mRNA expression of intracellular mediators of protein turnover. Secondary outcomes: maximum muscle strength and muscle power measured by maximum voluntary contraction...... and leg-extensor-power tests, body composition assessed by DXA scan, and systemic inflammation analyzed by circulating inflammatory markers, lipid and glucose metabolism in blood samples. Health related Quality of Life (QoL) will be assessed by validated questionnaires (EORTC QLQ-C30, SF-36). DISCUSSION...

  9. Increased response to insulin of glucose metabolism in the 6-day unloaded rat soleus muscle

    Science.gov (United States)

    Henriksen, Erik J.; Tischler, Marc E.; Johnson, David G.

    1986-01-01

    Hind leg muscles of female rats were unloaded by tail cast suspension for 6 days. In the fresh-frozen unloaded soleus, the significantly greater concentration of glycogen correlated with a lower activity ratio of glycogen phosphorylase (p less than 0.02). The activity ratio of glycogen synthase also was lower (p less than 0.001), possibly due to the higher concentration of glycogen. In isolated unloaded soleus, insulin (0.1 milliunit/ml) increased the oxidation of D(U-C-14) glucose, release of lactate and pyruvate, incorporation of D-(U-C-14) glucose into glycogen, and the concentration of glucose 6-phosphate more (p less than 0.05) than in the weight-bearing soleus. At physiological doses of insulin, the percent of maximal uptake of 2-deoxy-D-(1,2-H-3) glucose/muscle also was greater in the unloaded soleus. Unloading of the soleus increased, by 50 percent the concentration of insuling receptors, due to no decrease in total receptor number during muscle atrophy. This increase may account for the greater response of glucose metabolism to insulin in this muscle. The extensor digitorum longus, which generally shows little response to unloading, displayed no differential response of glucose metabolism to insulin.

  10. RESTLESS LEGS SYNDROME

    Directory of Open Access Journals (Sweden)

    Dmitriy Valer'evich Artem'ev

    2009-01-01

    Full Text Available The paper describes the epidemiology, etiology, pathogenesis, clinical picture, diagnosis, differential diagnosis, and treatment of restless legs syndrome. Recommendations are given how to choose therapeutic modalities and drugs in relation to different factors.

  11. Does mental exertion alter maximal muscle activation?

    Directory of Open Access Journals (Sweden)

    Vianney eRozand

    2014-09-01

    Full Text Available Mental exertion is known to impair endurance performance, but its effects on neuromuscular function remain unclear. The purpose of this study was to test the hypothesis that mental exertion reduces torque and muscle activation during intermittent maximal voluntary contractions of the knee extensors. Ten subjects performed in a randomized order three separate mental exertion conditions lasting 27 minutes each: i high mental exertion (incongruent Stroop task, ii moderate mental exertion (congruent Stroop task, iii low mental exertion (watching a movie. In each condition, mental exertion was combined with ten intermittent maximal voluntary contractions of the knee extensor muscles (one maximal voluntary contraction every 3 minutes. Neuromuscular function was assessed using electrical nerve stimulation. Maximal voluntary torque, maximal muscle activation and other neuromuscular parameters were similar across mental exertion conditions and did not change over time. These findings suggest that mental exertion does not affect neuromuscular function during intermittent maximal voluntary contractions of the knee extensors.

  12. Transfer of extensor digiti minimi and extensor carpi ulnaris nerve branches to the intrinsic motor nerve branches: A histological study on cadaver.

    Science.gov (United States)

    Namazi, H; Haji Vandi, S

    2017-06-01

    In cases of high ulnar and median nerve palsy, result of nerve repair in term of intrinsic muscle recovery is unsatisfactory. Distal nerve transfer can alleviate the regeneration time and improve the results. Transfer of the extensor digiti minimi (EDM) and extensor carpi ulnaris (ECU) nerve branches to the deep branch of ulnar nerve (DBUN)/recurrent branch of median nerve (RMN) at wrist had been used to restore intrinsic hand function but, incomplete recovery occurred. The axon count at the donor nerve has a strong influence on the final results. This cadaveric study aims to analyses the histology of this nerve transfer to evaluate whether these donor nerves are suitable for this transfer or another donor nerve may be considered. Ten cadaveric upper limbs dissected to identify the location of the EDM, ECU, RMN and DBUN. Surface area, fascicle count, and axon number was determined by histological methods. The mean of axon number in the EDM, ECU, RMN and DBUN branches was 5931, 7355, 30960 and 35426, respectively. In this study, the number of axons in the EDM and ECU branches was 37% (13281/35426) of that in the DBUN. Also, the number of axons in the EDM and ECU branches was 42% (13281/30960) of that in the RMN. The axon count data showed an unfavorable match between the EDM, ECU and DBUN/RMN. Therefore, it is suggested that another donor nerve with higher axon number to be considered. Cadaver study (histological study). Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  13. Muscle fatigue in relation to forearm pain and tenderness among professional computer users

    DEFF Research Database (Denmark)

    Thomsen, GF; Johnson, PW; Svendsen, Susanne Wulff

    2007-01-01

    ABSTRACT: BACKGROUND: To examine the hypothesis that forearm pain with palpation tenderness in computer users is associated with increased extensor muscle fatigue. METHODS: Eighteen persons with pain and moderate to severe palpation tenderness in the extensor muscle group of the right forearm...... response was not explained by differences in the MVC or body mass index. CONCLUSION: Computer users with forearm pain and moderate to severe palpation tenderness had diminished forearm extensor muscle fatigue response. Additional studies are necessary to determine whether this result reflects an adaptive...... and twenty gender and age matched referents without such complaints were enrolled from the Danish NUDATA study of neck and upper extremity disorders among technical assistants and machine technicians. Fatigue of the right forearm extensor muscles was assessed by muscle twitch forces in response to low...

  14. Dynamic Leg Exercise Improves Tolerance to Lower Body Negative Pressure

    Science.gov (United States)

    Watenpaugh, D. E.; Ballard, R. E.; Stout, M. S.; Murthy, G.; Whalen, R. T.; Hargens, A. R.

    1994-01-01

    These results clearly demonstrate that dynamic leg exercise against the footward force produced by LBNP substantially improves tolerance to LBNP, and that even cyclic ankle flexion without load bearing also increases tolerance. This exercise-induced increase of tolerance was actually an underestimate, because subjects who completed the tolerance test while exercising could have continued for longer periods. Exercise probably increases LBNP tolerance by multiple mechanisms. Tolerance was increased in part by skeletal muscle pumping venous blood from the legs. Rosenhamer and Linnarsson and Rosenhamer also deduced this for subjects cycling during centrifugation, although no measurements of leg volume were made in those studies: they found that male subjects cycling at 98 W could endure 3 Gz centrifugation longer than when they remained relaxed during centrifugation. Skeletal muscle pumping helps maintain cardiac filling pressure by opposing gravity-, centrifugation-, or LBNP-induced accumulation of blood and extravascular fluid in the legs.

  15. 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.

  16. The effect of an intensive exercise programme on leg function in chronic stroke patients: a pilot study with one-year follow-up.

    Science.gov (United States)

    Stock, Roland; Mork, Paul Jarle

    2009-09-01

    To investigate the effect of two weeks of intensive exercise on leg function in chronic stroke patients and to evaluate the feasibility of an intensive exercise programme in a group setting. Pilot study with one-group pre-test post-test design with two pre-tests and one-year follow-up. Inpatient rehabilitation hospital. Twelve hemiparetic patients completed the intervention. Ten patients participated at one-year follow-up. Six hours of daily intensive exercise for two weeks with focus on weight-shifting towards the affected side and increased use of the affected extremity during functional activities. An insole with nubs in the shoe of the non-paretic limb was used to reinforce weight-shift toward the affected side. Timed Up and Go, Four Square Step Test, gait velocity, gait symmetry and muscle strength in knee and ankle muscles. Maximal gait velocity (P = 0.002) and performance time (seconds) on Timed Up and Go (mean, SD; 12.2, 3.8 vs. 9.4, 3.2) and Four Square Step Test improved from pre- to post-test (P = 0.005). Improvements remained significant at follow-up. Preferred gait velocity and gait symmetry remained unchanged. Knee extensor (Pstroke patients. Most improvements persisted at the one-year follow-up.

  17. Effect of transcutaneous electrical muscle stimulation on postoperative muscle mass and protein synthesis

    DEFF Research Database (Denmark)

    Vinge, O; Edvardsen, L; Jensen, F

    1996-01-01

    In an experimental study, 13 patients undergoing major elective abdominal surgery were given postoperative transcutaneous electrical muscle stimulation (TEMS) to the quadriceps femoris muscle on one leg; the opposite leg served as control. Changes in cross-sectional area (CSA) and muscle protein ...... protein synthesis and muscle mass after abdominal surgery and should be evaluated in other catabolic states with muscle wasting.......In an experimental study, 13 patients undergoing major elective abdominal surgery were given postoperative transcutaneous electrical muscle stimulation (TEMS) to the quadriceps femoris muscle on one leg; the opposite leg served as control. Changes in cross-sectional area (CSA) and muscle protein...... synthesis were assessed by computed tomography and ribosome analysis of percutaneous muscle biopsies before surgery and on the sixth postoperative day. The percentage of polyribosomes in the ribosome suspension decreased significantly (P

  18. The interaction between the vastus medialis and vastus intermedius and its influence on the extensor apparatus of the knee joint.

    Science.gov (United States)

    Grob, Karl; Manestar, Mirjana; Filgueira, Luis; Kuster, Markus S; Gilbey, Helen; Ackland, Timothy

    2018-03-01

    Although the vastus medialis (VM) is closely associated with the vastus intermedius (VI), there is a lack of data regarding their functional relationship. The purpose of this study was to investigate the anatomical interaction between the VM and VI with regard to their origins, insertions, innervation and function within the extensor apparatus of the knee joint. Eighteen human cadaveric lower limbs were investigated using macro-dissection techniques. Six limbs were cut transversely in the middle third of the thigh. The mode of origin, insertion and nerve supply of the extensor apparatus of the knee joint were studied. The architecture of the VM and VI was examined in detail, as was their anatomical interaction and connective tissue linkage to the adjacent anatomical structures. The VM originated medially from a broad hammock-like structure. The attachment site of the VM always spanned over a long distance between: (1) patella, (2) rectus femoris tendon and (3) aponeurosis of the VI, with the insertion into the VI being the largest. VM units were inserted twice-once on the anterior and once on the posterior side of the VI. The VI consists of a complex multi-layered structure. The layers of the medial VI aponeurosis fused with the aponeuroses of the tensor vastus intermedius and vastus lateralis. Together, they form the two-layered intermediate layer of the quadriceps tendon. The VM and medial parts of the VI were innervated by the same medial division of the femoral nerve. The VM consists of multiple muscle units inserting into the entire VI. Together, they build a potential functional muscular complex. Therefore, the VM acts as an indirect extensor of the knee joint regulating and adjusting the length of the extensor apparatus throughout the entire range of motion. It is of clinical importance that, besides the VM, substantial parts of the VI directly contribute to the medial pull on the patella and help to maintain medial tracking of the patella during knee

  19. Artificial Leg Design and Control Research of a Biped Robot with Heterogeneous Legs Based on PID Control Algorithm

    Directory of Open Access Journals (Sweden)

    Hualong Xie

    2015-04-01

    Full Text Available A biped robot with heterogeneous legs (BRHL is proposed to provide an ideal test-bed for intelligent bionic legs (IBL. To make artificial leg gait better suited to a human, a four-bar mechanism is used as its knee joint, and a pneumatic artificial muscle (PAM is used as its driving source. The static mathematical model of PAM is established and the mechanical model of a single degree of freedom of a knee joint driven by PAM is analyzed. A control simulation of an artificial leg based on PID control algorithm is carried out and the simulation results indicate that the artificial leg can simulate precisely a normal human walking gait.

  20. Effect of mental fatigue on induced tremor in human knee extensors.

    Science.gov (United States)

    Budini, Francesco; Lowery, Madeleine; Durbaba, Rade; De Vito, Giuseppe

    2014-06-01

    In this study, the effects of mental fatigue on mechanically induced tremor at both a low (3-6Hz) and high (8-12Hz) frequency were investigated. The two distinct tremor frequencies were evoked using two springs of different stiffness, during 20s sustained contractions of the knee extensor muscles at 30% maximum voluntary contraction (MVC) before and after 100min of a mental fatigue task, in 12 healthy (29±3.7years) participants. Mental fatigue resulted in a 6.9% decrease in MVC and in a 9.4% decrease in the amplitude of the agonist muscle EMG during sustained 30% MVC contractions in the induced high frequency only. Following the mental fatigue task, the coefficient of variation and standard deviation of the force signal decreased at 8-12Hz induced tremor by 31.7% and 35.2% respectively, but not at 3-6Hz induced tremor. Similarly, the maximum value and area underneath the peak in the power spectrum of the force signal decreased by 55.5% and 53.1% respectively in the 8-12Hz range only. In conclusion, mental fatigue decreased mechanically induced 8-12Hz tremor and had no effect on induced 3-6Hz tremor. We suggest that the reduction could be attributed to the decreased activation of the agonist muscles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Approach to leg edema

    Directory of Open Access Journals (Sweden)

    Fulvio Pomero

    2017-09-01

    Full Text Available Edema is defined as a palpable swelling caused by an increase in interstitial fluid volume. Leg edema is a common problem with a wide range of possible causes and is the result of an imbalance in the filtration system between the capillary and interstitial spaces. Major causes of edema include venous obstruction, increased capillary permeability and increased plasma volume secondary to sodium and water retention. In both hospital and general practice, the patient with a swollen leg presents a common dilemma in diagnosis and treatment. The cause may be trivial or life-threatening and it is often difficult to determine the clinical pathway. The diagnosis can be narrowed by categorizing the edema according to its duration, distribution (unilateral or bilateral and accompanying symptoms. This work provides clinically oriented recommendations for the management of leg edema in adults.

  2. Leg som ustyrlig deltagelseskultur

    DEFF Research Database (Denmark)

    Toft, Herdis

    2017-01-01

    - og spilteoretikere Johan Huizinga og Roger Caillois. Deres teorier og begrebsdannelser har været brugt til at påpege leg dels som et æstetisk baseret betydningssystem, dels som et affektivt og stemningsbaseret oplevelsessystem samt endelig som et socialt baseret relationssystem. I artiklen vælger vi...... at fokusere på leg som et socialt baseret relationssystem og yderligere zoome ind på et af legens systemiske væsenstræk, nemlig brugen af regulerbare regelsæt, som legerne uden ’politi’ forhandler sig frem til før, under og efter legen. Fælles for Huizinga og Caillois er, at de knytter leg uløseligt sammen...

  3. Leg og dannelse

    DEFF Research Database (Denmark)

    Skovbjerg, Helle Marie

    2017-01-01

    lederen i det pædagogiske tidskrift Asterisk: ”Leg i skolen, leg i klasserummet, ja legende læring i skolen udgør derimod en enorm, seriøs og ubrugt læringsressource – ikke alene med effekter på kreativiteten, men også på den faglige læring” (Holm, 2015, p. 2). Legens værdi gøres altså først og fremmest...

  4. Venous leg ulcers

    Science.gov (United States)

    2008-01-01

    Introduction Leg ulcers usually occur secondary to venous reflux or obstruction, but 20% of people with leg ulcers have arterial disease, with or without venous disorders. Between 1.5 and 3.0/1000 people have active leg ulcers. Prevalence increases with age to about 20/1000 in people aged over 80 years. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of standard treatments, adjuvant treatments, and organisational interventions for venous leg ulcers? What are the effects of interventions to prevent recurrence of venous leg ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 80 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: compression bandages and stockings, cultured allogenic (single or bilayer) skin replacement, debriding agents, dressings (cellulose, collagen, film, foam, hyaluronic acid-derived, semi-occlusive alginate), hydrocolloid (occlusive) dressings in the presence of compression, intermittent pneumatic compression, intravenous prostaglandin E1, larval therapy, laser treatment (low-level), leg ulcer clinics, multilayer elastic system, multilayer elastomeric (or non-elastomeric) high-compression regimens or bandages, oral treatments (aspirin, flavonoids, pentoxifylline, rutosides, stanozolol, sulodexide, thromboxane alpha2 antagonists, zinc), peri

  5. Muscle blood flow at onset of dynamic exercise in humans.

    Science.gov (United States)

    Rådegran, G; Saltin, B

    1998-01-01

    To evaluate the temporal relationship between blood flow, blood pressure, and muscle contractions, we continuously measured femoral arterial inflow with ultrasound Doppler at onset of passive exercise and voluntary, one-legged, dynamic knee-extensor exercise in humans. Blood velocity and inflow increased (P dicrotic and diastolic blood pressure notches, respectively. Mechanical hindrance occurred (P dicrotic notch. The increase in blood flow (Q) was characterized by a one-component (approximately 15% of peak power output), two-component (approximately 40-70% of peak power output), or three-component exponential model (> or = 75% of peak power output), where Q(t) = Qpassive + delta Q1.[1 - e-(t - TD1/tau 1)]+ delta Q2.[1 - e-(t - TD2/tau 2)]+ delta Q3.[1 - e-(t - TD3/tau 3)]; Qpassive, the blood flow during passive leg movement, equals 1.17 +/- 0.11 l/min; TD is the onset latency; tau is the time constant; delta Q is the magnitude of blood flow rise; and subscripts 1-3 refer to the first, second, and third components of the exponential model, respectively. The time to reach 50% of the difference between passive and voluntary asymptotic blood flow was approximately 2.2-8.9 s. The blood flow leveled off after approximately 10-150 s, related to the power outputs. It is concluded that the elevation in blood flow with the first duty cycle(s) is due to muscle mechanical factors, but vasodilators initiate a more potent amplification within the second to fourth contraction.

  6. Spontaneous atraumatic extensor pollicis longus rupture in the nonrheumatoid population.

    Science.gov (United States)

    Rada, Erin M; Shridharani, Sachin M; Lifchez, Scott D

    2013-01-01

    Extensor pollicis longus (EPL) tendon rupture is a well-described phenomenon in patients with rheumatoid arthritis. Mechanisms of EPL tendon rupture in the nonrheumatoid population have also been described and include traumatic rupture, repetitive motion strain, and steroid injection into the tendon. The operative records for patients undergoing extensor pollicis longus reconstruction by the senior author were reviewed. Patients with a history of trauma to the wrist or inflammatory arthropathy were excluded. We identified 3 patients who presented with spontaneous EPL tendon rupture. These patients reported no risk factors (as listed earlier) or inciting event. All 3 patients had some exposure to local steroids but this exposure was not at the site of subsequent tendon rupture. All patients were operatively repaired and went on to full recovery of EPL function. In patients with sudden loss of extension of the thumb interphalangeal joint, a thorough history of steroid exposure including local steroid exposure remote to the affected EPL tendon may be relevant.

  7. Multiple Tophaceous Gout of Hand with Extensor Tendon Rupture

    Directory of Open Access Journals (Sweden)

    Haruki Tobimatsu

    2017-01-01

    Full Text Available A 45-year-old man presented with painless subcutaneous masses bilaterally on his hands and loss of motion or contracture of the fingers. Initially, drug therapy to reduce the serum uric acid was administered and was expected to reduce the tophi. However, during observation at the clinic, spontaneous rupture of an extensor tendon occurred, and surgical repair of the tendon and resection of the masses were performed. Surgical exploration of the right hand showed hypertrophic white-colored crystal deposits that both surrounded and invaded the extensor digitorum communis of the index finger, which was ruptured. Histopathologic examination of the specimen demonstrated findings consistent with gouty tophi. Tophaceous gout can induce a rupture of tendons during clinical observation, and surgical resection of the tophi might be needed to prevent ruptures.

  8. The effects of a passive exoskeleton on muscle activity, discomfort and endurance time in forward bending work.

    Science.gov (United States)

    Bosch, Tim; van Eck, Jennifer; Knitel, Karlijn; de Looze, Michiel

    2016-05-01

    Exoskeletons may form a new strategy to reduce the risk of developing low back pain in stressful jobs. In the present study we examined the potential of a so-called passive exoskeleton on muscle activity, discomfort and endurance time in prolonged forward-bended working postures. Eighteen subjects performed two tasks: a simulated assembly task with the trunk in a forward-bended position and static holding of the same trunk position without further activity. We measured the electromyography for muscles in the back, abdomen and legs. We also measured the perceived local discomfort. In the static holding task we determined the endurance, defined as the time that people could continue without passing a specified discomfort threshold. In the assembly task we found lower muscle activity (by 35-38%) and lower discomfort in the low back when wearing the exoskeleton. Additionally, the hip extensor activity was reduced. The exoskeleton led to more discomfort in the chest region. In the task of static holding, we observed that exoskeleton use led to an increase in endurance time from 3.2 to 9.7 min, on average. The results illustrate the good potential of this passive exoskeleton to reduce the internal muscle forces and (reactive) spinal forces in the lumbar region. However, the adoption of an over-extended knee position might be, among others, one of the concerns when using the exoskeleton. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  9. Restless Legs Syndrome

    Science.gov (United States)

    ... disorder, particularly if they experience onset at an early age; many years may pass before symptoms occur regularly. top What causes restless legs syndrome? In most cases, the cause of RLS is unknown (called primary RLS). However, RLS has a genetic component and ...

  10. The mangled lower leg

    NARCIS (Netherlands)

    Hoogendoorn, Jochem Maarten

    2002-01-01

    A surgeon faced with a patient presenting with an open tibial/fibular fracture in combination with severe damage of the surrounding soft tissues, has to make the difficult decision whether to attempt salvage or to perform an immediate amputation of the leg. Until late in the nineteenth century the

  11. TRAINING-INDUCED CHANGES IN THE TOPOGRAPHY OF MUSCLE TORQUES AND MAXIMAL MUSCLE TORQUES IN BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Krzysztof Buśko

    2012-01-01

    Full Text Available The aim of the study was to detect changes in the maximal muscle torques in male basketball players during a two-year training cycle. We verified the hypothesis that different workloads applied during the preparation and competition periods would result in changes in the maximal muscle torques of the athletes (increase during the former and decrease or no change during the latter period accompanied by no alteration of the percent muscle topography of all the muscle groups tested. The examinations were conducted on nine senior male basketball players from the Polish national team. Estimations of the muscle torques in static conditions were performed at the end of the preparation (measurements I and III and competition (measurements II and IV periods of a two-year training cycle. Eleven muscle groups were studied including flexors and extensors of the trunk and flexors and extensors of the shoulder, the elbow, the hip, the knee, and the ankle. Muscle torques of the shoulder and the elbow insignificantly decreased except for the muscle torque of the flexors of the shoulder. Muscle torques of the flexors and extensors of the trunk as well as of the flexors and extensors of the hip, the knee, and the ankle increased between measurements I and III and between measurements I and IV with the only exception being the muscle torque of the flexors of the knee (which significantly decreased by 7.4% In the case of the flexors and extensors of the trunk and the flexors and extensors of the hip, the changes appeared to be significant. The sum of the muscle torques of the upper limbs markedly decreased between the preparation (measurement I and competition (measurement IV periods. The sum of the muscle torques of the trunk and the lower limbs and the sum of the muscle torques of the eleven muscle groups significantly increased between measurements I and IV. Percent muscle topography significantly decreased for the flexors and extensors of the shoulder and the

  12. Whole-body electromyostimulation as a means to impact muscle mass and abdominal body fat in lean, sedentary, older female adults: subanalysis of the TEST-III trial

    Directory of Open Access Journals (Sweden)

    Kemmler W

    2013-10-01

    Full Text Available Wolfgang Kemmler, Simon von StengelInstitute of Medical Physics, University of Erlangen-Nürnberg, Erlangen, GermanyBackground: The primary aim of this study was to determine the effect of 12 months of whole-body electromyostimulation (WB-EMS exercise on appendicular muscle mass and abdominal fat mass in subjects specifically at risk for sarcopenia and abdominal obesity, but unable or unwilling to exercise conventionally.Methods: Forty-six lean, nonsportive (<60 minutes of exercise per week, elderly women (aged 75 ± 4 years with abdominal obesity according to International Diabetes Federation criteria were randomly assigned to either a WB-EMS group (n=23 which performed 18 minutes of intermittent, bipolar WB-EMS (85 Hz three sessions in 14 days or an "active" control group (n=23. Whole-body and regional body composition was assessed by dual energy X-ray absorptiometry to determine appendicular muscle mass, upper leg muscle mass, abdominal fat mass, and upper leg fat mass. Maximum strength of the leg extensors was determined isometrically by force plates.Results: After 12 months, significant intergroup differences were detected for the primary endpoints of appendicular muscle mass (0.5% ± 2.0% for the WB-EMS group versus −0.8% ± 2.0% for the control group, P=0.025 and abdominal fat mass (−1.2% ± 5.9% for the WB-EMS group versus 2.4% ± 5.8% for the control group, P=0.038. Further, upper leg lean muscle mass changed favorably in the WB-EMS group (0.5% ± 2.5% versus −0.9% ± 1.9%, in the control group, P=0.033, while effects for upper leg fat mass were borderline nonsignificant (−0.8% ± 3.5% for the WB-EMS group versus 1.0% ± 2.6% for the control group, P=0.050. With respect to functional parameters, the effects for leg extensor strength were again significant, with more favorable changes in the WB-EMS group (9.1% ± 11.2% versus 1.0% ± 8.1% in the control group, P=0.010.Conclusion: In summary, WB-EMS showed positive effects on the

  13. Leg tissue composition and physico-chemical parameters of sheep meat fed annatto coproduct

    Directory of Open Access Journals (Sweden)

    Dorgival Morais de Lima Júnior

    2017-10-01

    Full Text Available Our objective was to evaluate leg tissue composition and physico-chemical quality parameters of sheep meat fed with increasing levels of annatto coproduct. 32 male uncastrated animals without a defined breed were randomized in four treatments (0, 100, 200 and 300 g kg-1 of annatto coproduct in the DM diet. After 78 days of confinement, the animals were slaughtered and body components were recorded. Reconstituted leg weight, total muscle weight, biceps weight and semitendinosus weight showed a negative linear behavior (P 0.05 were found for leg tissue composition (%, muscle:bone ratio, relative fat or leg muscle. Meat physico-chemical parameters (color, shear force, water retention capacity and cooking losses were not affected by the inclusion of the annatto coproduct in the diet. The annatto coproduct can be included in up to 300 g kg-1 of dietary dry matter without negative effects to the leg tissue composition (% and physical parameters of confined sheep meat.

  14. Surface EMG characteristics of people with multiple sclerosis during static contractions of the knee extensors.

    Science.gov (United States)

    Scott, Sasha M; Hughes, Adrienne R; Galloway, Stuart D R; Hunter, Angus M

    2011-01-01

    This study was designed to determine whether any alterations existed in surface electromyography (sEMG) in people with multiple sclerosis (MS) during isometric contractions of the knee extensors. Fifteen people with MS and 14 matched controls (mean ± SD age and body mass index 53·7 ± 10·5 versus 54·6 ± 9·6 years and 27·7 ± 6·1 versus 26·5 ± 4, respectively) completed 20%, 40%, 60% and 80% of their maximal voluntary contraction (MVC) of the knee extensors. sEMG was recorded from the vastus lateralis where muscle fibre conduction velocity (MFCV) and sEMG amplitude (RMS) were assessed. Body composition was determined using dual-energy X-ray absorptiometry and physical activity with the use of accelerometry. People with MS showed significantly (P<0·05) faster MFCV during MVC (6·6 ± 2·7 versus 4·7 ± 1·4 m s(-1) ) and all submaximal contractions, while RMS was significantly (P<0·05) less (0·11 ± 0·03 versus 0·24 ± 0·06 mV) in comparison with the controls. MVC along with specific thigh lean mass to torque, rate of force development and mean physical activity were significantly (P<0·01) less in PwMS. People with MS have elevated MFCV alongside reduced RMS during isometric contraction. This elevation in MFCV should be accounted for when interpreting sEMG from people with MS. © 2010 University of Stirling. Clinical physiology and Functional Imaging © 2010 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

  15. Fatigue effects on tracking performance and muscle activity

    NARCIS (Netherlands)

    Huysmans, M.A.; Hoozemans, M.J.M.; van der Beek, A.J.; de Looze, M.P.; van Dieen, J.H.

    2008-01-01

    It has been suggested that fatigue affects proprioception and consequently movement accuracy, the effects of which may be counteracted by increased muscle activity. To determine the effects of fatigue on tracking performance and muscle activity in the M. extensor carpi radialis (ECR), 11 female

  16. 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.

  17. Activation of plantar flexor muscles is constrained by multiple muscle synergies rather than joint torques.

    Directory of Open Access Journals (Sweden)

    Takahito Suzuki

    Full Text Available Behavioral evidence has suggested that a small number of muscle synergies may be responsible for activating a variety of muscles. Nevertheless, such dimensionality reduction may also be explained using the perspective of alternative hypotheses, such as predictions based on linear combinations of joint torques multiplied by corresponding coefficients. To compare the explanatory capacity of these hypotheses for describing muscle activation, we enrolled 12 male volunteers who performed isometric plantar flexor contractions at 10-100% of maximum effort. During each plantar flexor contraction, the knee extensor muscles were isometrically contracted at 0%, 50%, or 100% of maximum effort. Electromyographic activity was recorded from the vastus lateralis, medial gastrocnemius (MG, lateral gastrocnemius (LG, and soleus muscles and quantified using the average rectified value (ARV. At lower plantar flexion torque, regression analysis identified a clear linear relationship between the MG and soleus ARVs and between the MG and LG ARVs, suggesting the presence of muscle synergy (r2 > 0.65. The contraction of the knee extensor muscles induced a significant change in the slope of this relationship for both pairs of muscles (MG × soleus, P = 0.002; MG × LG, P = 0.006. Similarly, the slope of the linear relationship between the plantar flexion torque and the ARV of the MG or soleus changed significantly with knee extensor contraction (P = 0.031 and P = 0.041, respectively. These results suggest that muscle synergies characterized by non-mechanical constraints are selectively recruited according to whether contraction of the knee extensor muscles is performed simultaneously, which is relatively consistent with the muscle synergy hypothesis.

  18. Torze kolenních extenzorových svalů během izometrických cvičení a ruská elektrická stimulace po zranění kolenních vazů Knee extensor muscles' torque during isometric exercises and russian electrical stimulation following a knee ligament injury

    Directory of Open Access Journals (Sweden)

    Maciej Płaszewski

    2007-02-01

    Full Text Available Dobrovolné izometrické cvičení (VOL i neuromuskulární elektrická stimulace (NMES jsou metody rozvoje statické svalové síly. Používají se v programech pro rozvoj síly u zdravých svalů a také pro zotavování svalové funkce za určitých ortopedických podmínek. Obě metody se používají pro zpomalování svalové atrofie a ztráty síly v důsledku imobilizace kolena po zranění (Eriksson & Häggmark, 1979; Ingemann-Hansen & Halkjær-Kristensen, 1985; Johnson, 1988; Wigerstad-Lossing, Tromby, Jonsson, Morelli, Peterson, & Rentröm, 1988. NMES může vyvolat záškuby nebo tetanické svalové kontrakce, a to v závislosti na frekvenci proudových impulsů. Během tetanické stimulace jsou hlavními rysy nácvikových režimů: 1 cyklus zapnutí/vypnutí (pracovní cyklus, tvořený dobou kontrakce a dobou uvolnění; 2 počet kontrakcí; 3 intenzita kontrakcí (dána proudovou amplitudou nebo tolerancí subjektu. Voluntary isometric exercise (VOL and neuromuscular electrical stimulation (NMES are both methods of static muscle strength and girth training. They are applied in strength training programs to healthy muscle as well as for muscle function recovery under certain orthopaedic conditions. Both methods are used to retard muscle atrophy and strength loss resulting from post injury knee immobilization (Eriksson & Häggmark, 1979; Ingemann-Hansen & Halkjær-Kristensen, 1985; Johnson, 1988; Wigerstad-Lossing, Tromby, Jonsson, Morelli, Peterson, & Rentröm, 1988. NMES can elicit twitch or tetanic muscle contractions, determined by current pulse frequency. During tetanic stimulation, the main features of training regimes are: 1 on/off cycle (or duty cycle, made up of the time of contraction plus rest time; 2 the number of contractions; 3 the intensity of contractions (determined by the current amplitude and/or the subject’s tolerance.

  19. Dynamically Stable Legged Locomotion.

    Science.gov (United States)

    1983-01-27

    digitai~y thro)ugh a ribbon cable. lhe dcsign effort required to mount power sources and computing u(m board would hive distracted us fiorn our main...angular momentum. "The model used in this paper, shown in Fig. 6-1, has 3 single springy leg that articular •s ,ith respect to a body about a simple hince

  20. Two Legged Walking Robot

    OpenAIRE

    Kraus, V.

    2015-01-01

    The aim of this work is to construct a two-legged wirelessly controlled walking robot. This paper describes the construction of the robot, its control electronics, and the solution of the wireless control. The article also includes a description of the application to control the robot. The control electronics of the walking robot are built using the development kit Arduino Mega, which is enhanced with WiFi module allowing the wireless control, a set of ultrasonic sensors for detecting obstacl...

  1. Dynamically Stable Legged Locomotion

    Science.gov (United States)

    1981-11-30

    the laboratory. Harry Asada, Wayne Book, Nancy Cornelius, Sesh Murthy and Ivan Sutherland read various drafts of this report, for which we are...particularly helpful in providing an atmosphere where things could get started. Craig Fields and Clint Kelly deserve special credit for letting the idea of...legged technology capture their imaginations, even before we could show them tangible results. We are especially indebted to Ivan Sutherland for his

  2. Legāti

    OpenAIRE

    Segliņa, Aiga

    2010-01-01

    Autore teorētiski analizē legāta jēdzienu testamentārās mantošanas ietvaros un atspoguļo praktiska pētījuma rezultātus. Teorētiskā daļa apskata legāta nodibināšanas formu un spēkā esamību, tā iegūšanu un atraidīšanu, izpildi un zaudēšanu, novēlējuma robežas un aprobežojumus. Pētījums veikts aptaujas veidā ar mērķi noskaidrot, cik liela Latvijas iedzīvotāju daļa apzinās legāta nodrošinātās priekšrocības testamentārajā mantošanā. Apskatīts notāra neitralitātes jautājums attiecībā pret mantošana...

  3. Development and Physical Control Research on Prototype Artificial Leg

    Directory of Open Access Journals (Sweden)

    Fei Li

    2016-03-01

    Full Text Available To provide an ideal platform for research on intelligent bionic leg (IBL, this paper proposes a model of a biped robot with heterogeneous legs (BRHL. A prototype of an artificial leg is developed based on biological structure and motion principle analysis of human lower extremities. With regard to the driving sources, servomotors are chosen for the hip joint and ankle joint, while pneumatic muscle actuators (PMAs are chosen for the knee joint. The control system of the bionic artificial leg is designed and a physical experimental platform is established. The physical control experiments are done based on proportional-integral-derivative (PID control strategy. The experimental results show that such a system can realize the expected goals.

  4. Mechanical evidence that flamingos can support their body on one leg with little active muscular force.

    Science.gov (United States)

    Chang, Young-Hui; Ting, Lena H

    2017-05-01

    Flamingos (Phoenicopteridae) often stand and sleep on one leg for long periods, but it is unknown how much active muscle contractile force they use for the mechanical demands of standing on one leg: body weight support and maintaining balance. First, we demonstrated that flamingo cadavers could passively support body weight on one leg without any muscle activity while adopting a stable, unchanging, joint posture resembling that seen in live flamingos. By contrast, the cadaveric flamingo could not be stably held in a two-legged pose, suggesting a greater necessity for active muscle force to stabilize two-legged versus one-legged postures. Our results suggest that flamingos engage a passively engaged gravitational stay apparatus (proximally located) for weight support during one-legged standing. Second, we discovered that live flamingos standing on one leg have markedly reduced body sway during quiescent versus alert behaviours, with the point of force application directly under the distal joint, reducing the need for muscular joint torque. Taken together, our results highlight the possibility that flamingos stand for long durations on one leg without exacting high muscular forces and, thus, with little energetic expenditure. © 2017 The Author(s).

  5. X-Ray Exam: Lower Leg (Tibia and Fibula)

    Science.gov (United States)

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