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Sample records for submaximal cycle ergometer

  1. Actual Versus Predicted Cardiovascular Demands in Submaximal Cycle Ergometer Testing.

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    Hoehn, Amanda M; Mullenbach, Megan J; Fountaine, Charles J

    The Astrand-Rhyming cycle ergometer test (ARCET) is a commonly administered submaximal test for estimating aerobic capacity. Whereas typically utilized in clinical populations, the validity of the ARCET to predict VO 2max in a non-clinical population, especially female, is less clear. Therefore, the purpose of this study was to determine the accuracy of the ARCET in a sample of healthy and physically active college students. Subjects (13 females, 10 males) performed a maximal cycle ergometer test to volitional exhaustion to determine VO 2max . At least 48 hours later, subjects performed the ARCET protocol. Predicted VO 2max was calculated following the ARCET format using the age corrected factor. There was no significant difference (p=.045) between actual (41.0±7.97 ml/kg/min) and predicted VO 2max (40.3±7.58 ml/kg/min). When split for gender there was a significant difference between actual and predicted VO 2 for males, (45.1±7.74 vs. 42.7±8.26 ml/kg/min, p=0.029) but no significant difference observed for females, (37.9±6.9 vs. 38.5±6.77 ml/kg/min, p=0.675). The correlation between actual and predicted VO 2 was r=0.84, phealthy college population of both male and female subjects. Implications of this study suggest the ARCET can be used to assess aerobic capacity in both fitness and clinical settings where measurement via open-circuit spirometry is either unavailable or impractical.

  2. A new submaximal cycle ergometer test for prediction of VO2max.

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    Ekblom-Bak, E; Björkman, F; Hellenius, M-L; Ekblom, B

    2014-04-01

    Maximal oxygen uptake (VO2max) is an important, independent predictor of cardiovascular health and mortality. Despite this, it is rarely measured in clinical practice. The aim of this study was to create and evaluate a submaximal cycle ergometry test based on change in heart rate (HR) between a lower standard work rate and an individually chosen higher work rate. In a mixed population (n = 143) with regard to sex (55% women), age (21-65 years), and activity status (inactive to highly active), a model included change in HR per unit change in power, sex, and age for the best estimate of VO2max. The association between estimated and observed VO2max for the mixed sample was r = 0.91, standard error of estimate = 0.302 L/min, and mean measured VO2max = 3.23 L/min. The corresponding coefficient of variation was 9.3%, a significantly improved precision compared with one of the most commonly used submaximal exercise tests, the Åstrand test, which in the present study was estimated to be 18.1%. Test-retest reliability analysis over 1 week revealed no mean difference in the estimated VO2max (-0.02 L/min, 95% confidence interval: -0.07-0.03). The new test is low-risk, easily administered, and valid for a wide capacity range, and is therefore suitable in situations as health evaluations in the general population. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. A New Submaximal Rowing Test to Predict 2,000-m Rowing Ergometer Performance

    NARCIS (Netherlands)

    Otter, Ruby T. A.; Brink, Michel S.; Lamberts, Robert P.; Lemmink, Koen A. P. M.

    Otter, RTA, Brink, MS, Lamberts, RP, and Lemmink, KAPM. A new submaximal rowing test to predict 2,000-m rowing ergometer performance. J Strength Cond Res 29(9): 2426-2433, 2015-The purpose of this study was to assess predictive value of a new submaximal rowing test (SmRT) on 2,000-m ergometer rowing

  4. Comparison of Exercise Performance on Rowing and Cycle Ergometers.

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    Mahler, Donald A.; And Others

    1987-01-01

    The purpose of this study was to compare exercise performance and cardiorespiratory responses on the rowing ergometer with those on the cycle ergometer. Findings are presented and explained. (Author/MT)

  5. A New Submaximal Rowing Test to Predict 2,000-m Rowing Ergometer Performance.

    Science.gov (United States)

    Otter, Ruby T A; Brink, Michel S; Lamberts, Robert P; Lemmink, Koen A P M

    2015-09-01

    The purpose of this study was to assess predictive value of a new submaximal rowing test (SmRT) on 2,000-m ergometer rowing time-trial performance in competitive rowers. In addition, the reliability of the SmRT was investigated. Twenty-four competitive male rowers participated in this study. After determining individual HRmax, all rowers performed an SmRT followed by a 2,000-m rowing ergometer time trial. In addition, the SmRT was performed 4 times (2 days in between) to determine the reliability. The SmRT consists of two 6-minute stages of rowing at 70 and 80% HRmax, followed by a 3-minute stage at 90% HRmax. Power was captured during the 3 stages, and 60 seconds of heart rate recovery (HRR60s) was measured directly after the third stage. Results showed that predictive value of power during the SmRT on 2,000-m rowing time also increased with stages. CVTEE% is 2.4, 1.9, and 1.3%. Pearson correlations (95% confidence interval [95% CI]) were -0.73 (-0.88 to -0.45), -0.80 (-0.94 to -0.67), and -0.93 (-0.97 to -0.84). 2,000-m rowing time and HRR60s showed no relationship. Reliability of power during the SmRT improved with the increasing intensity of the stages. The coefficient of variation (CVTEM%) was 9.2, 5.6, and 0.4%. Intraclass correlation coefficients (ICC) and 95% CI were 0.91 (0.78-0.97), 0.92 (0.81-0.97), and 0.99 (0.97-1.00). The CVTEM% and ICC of HRR60s were 8.1% and 0.93 (0.82-0.98). In conclusion, the data of this study shows that the SmRT is a reliable test that it is able to accurately predict 2,000-m rowing time on an ergometer. The SmRT is a practical and valuable submaximal test for rowers, which can potentially assist with monitoring, fine-tuning and optimizing training prescription in rowers.

  6. Spinal loads during cycling on an ergometer.

    Directory of Open Access Journals (Sweden)

    Antonius Rohlmann

    Full Text Available Cycling on an ergometer is an effective exercise for improving fitness. However, people with back problems or previous spinal surgery are often not aware of whether cycling could be harmful for them. To date, little information exists about spinal loads during cycling. A telemeterized vertebral body replacement allows in vivo measurement of implant loads during the activities of daily living. Five patients with a severe compression fracture of a lumbar vertebral body received these implants. During one measurement session, four of the participants exercised on a bicycle ergometer at various power levels. As the power level increased, the maximum resultant force and the difference between the maximum and minimum force (force range during each pedal revolution increased. The average maximum-force increases between the two power levels 25 and 85 W were 73, 84, 225 and 75 N for the four patients. The corresponding increases in the force range during a pedal revolution were 84, 98, 166 and 101 N. There were large variations in the measured forces between the patients and also within the same patient, especially for high power levels. In two patients, the maximum forces during high-power cycling were higher than the forces during walking measured on the same day. Therefore, the authors conclude that patients with back problems should not cycle at high power levels shortly after surgery as a precaution.

  7. The Measurement of Maximal (Anaerobic Power Output on a Cycle Ergometer: A Critical Review

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    Tarak Driss

    2013-01-01

    Full Text Available The interests and limits of the different methods and protocols of maximal (anaerobic power ( assessment are reviewed: single all-out tests versus force-velocity tests, isokinetic ergometers versus friction-loaded ergometers, measure of during the acceleration phase or at peak velocity. The effects of training, athletic practice, diet and pharmacological substances upon the production of maximal mechanical power are not discussed in this review mainly focused on the technical (ergometer, crank length, toe clips, methodological (protocols and biological factors (muscle volume, muscle fiber type, age, gender, growth, temperature, chronobiology and fatigue limiting in cycling. Although the validity of the Wingate test is questionable, a large part of the review is dedicated to this test which is currently the all-out cycling test the most often used. The biomechanical characteristics specific of maximal and high speed cycling, the bioenergetics of the all-out cycling exercises and the influence of biochemical factors (acidosis and alkalosis, phosphate ions… are recalled at the beginning of the paper. The basic knowledge concerning the consequences of the force-velocity relationship upon power output, the biomechanics of sub-maximal cycling exercises and the study on the force-velocity relationship in cycling by Dickinson in 1928 are presented in Appendices.

  8. Design and testing of an MRI-compatible cycle ergometer for non-invasive cardiac assessments during exercise

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    Gusso Silmara

    2012-03-01

    Full Text Available Abstract Background Magnetic resonance imaging (MRI is an important tool for cardiac research, and it is frequently used for resting cardiac assessments. However, research into non-pharmacological stress cardiac evaluation is limited. Methods We aimed to design a portable and relatively inexpensive MRI cycle ergometer capable of continuously measuring pedalling workload while patients exercise to maintain target heart rates. Results We constructed and tested an MRI-compatible cycle ergometer for a 1.5 T MRI scanner. Resting and sub-maximal exercise images (at 110 beats per minute were successfully obtained in 8 healthy adults. Conclusions The MRI-compatible cycle ergometer constructed by our research group enabled cardiac assessments at fixed heart rates, while continuously recording power output by directly measuring pedal force and crank rotation.

  9. An Innovative Ergometer to Measure Neuromuscular Fatigue Immediately after Cycling.

    Science.gov (United States)

    Doyle-Baker, Douglas; Temesi, John; Medysky, Mary E; Holash, Robert J; Millet, Guillaume Y

    2018-02-01

    When assessing neuromuscular fatigue (NMF) from dynamic exercise using large muscle mass (e.g., cycling), most studies have delayed measurement for 1 to 3 min after task failure. This study aimed to determine the reliability of an innovative cycling ergometer permitting the start of fatigue measurement within 1 s after cycling. Twelve subjects participated in two experimental sessions. Knee-extensor NMF was assessed by electrical nerve and transcranial magnetic stimulation with both a traditional chair setup (PRE- and POST-Chair, 2 min postexercise) and the new cycling ergometer (PRE, every 3 min during incremental exercise and POST-Bike, at task failure). The reduction in maximal voluntary contraction force POST-Bike (63% ± 12% PRE; P cycling protocol (P > 0.05). Vastus lateralis and rectus femoris M-wave and motor-evoked potential areas showed fair to excellent reliability (ICC, 0.45-0.88). The reduction in maximal voluntary contraction and Db100 was greater on the cycling ergometer than the isometric chair. The innovative cycling ergometer is a reliable tool to assess NMF during and immediately postexercise. This will allow fatigue etiology during dynamic exercise with large muscle mass to be revisited in various populations and environmental conditions.

  10. Determining power outputs for cycle ergometers with different sized flywheels.

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    Gledhill, N; Jamnik, R

    1995-01-01

    A number of cycle ergometers are presently being used in a variety of laboratory applications for which the quantification of power output is required. To calculate the power output of cycle ergometers with varying sized flywheels, the circumference of the resistance track on the flywheel is multiplied by the number of flywheel revolutions produced with one complete revolution of the pedal. This provides the "effective distance travelled," and by selecting an appropriate combination of pedalling rate plus flywheel resistance, any desired power output can be produced.

  11. Submaximal cardiopulmonary thresholds on a robotics-assisted tilt table, a cycle and a treadmill: a comparative analysis.

    Science.gov (United States)

    Saengsuwan, Jittima; Nef, Tobias; Laubacher, Marco; Hunt, Kenneth J

    2015-11-10

    The robotics-assisted tilt table (RATT), including actuators for tilting and cyclical leg movement, is used for rehabilitation of severely disabled neurological patients. Following further engineering development of the system, i.e. the addition of force sensors and visual bio-feedback, patients can actively participate in exercise testing and training on the device. Peak cardiopulmonary performance parameters were previously investigated, but it also important to compare submaximal parameters with standard devices. The aim of this study was to evaluate the feasibility of the RATT for estimation of submaximal exercise thresholds by comparison with a cycle ergometer and a treadmill. 17 healthy subjects randomly performed six maximal individualized incremental exercise tests, with two tests on each of the three exercise modalities. The ventilatory anaerobic threshold (VAT) and respiratory compensation point (RCP) were determined from breath-by-breath data. VAT and RCP on the RATT were lower than the cycle ergometer and the treadmill: oxygen uptake (V'O2) at VAT was [mean (SD)] 1.2 (0.3), 1.5 (0.4) and 1.6 (0.5) L/min, respectively (p < 0.001); V'O2 at RCP was 1.7 (0.4), 2.3 (0.8) and 2.6 (0.9) L/min, respectively (p = 0.001). High correlations for VAT and RCP were found between the RATT vs the cycle ergometer and RATT vs the treadmill (R on the range 0.69-0.80). VAT and RCP demonstrated excellent test-retest reliability for all three devices (ICC from 0.81 to 0.98). Mean differences between the test and retest values on each device were close to zero. The ventilatory equivalent for O2 at VAT for the RATT and cycle ergometer were similar and both were higher than the treadmill. The ventilatory equivalent for CO2 at RCP was similar for all devices. Ventilatory equivalent parameters demonstrated fair-to-excellent reliability and repeatability. It is feasible to use the RATT for estimation of submaximal exercise thresholds: VAT and RCP on the RATT were lower than the

  12. Analysis of anaerobic capacity in rowers using Wingate test on cycle and rowing ergometer.

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    Klasnja, Aleksandar; Barak, Otto; Popadić-Gaćesa, Jelena; Drapsin, Miodrag; Knezević, Aleksandar; Grujić, Nikola

    2010-01-01

    The 30-s all-out Wingate test has been used in athletes of all sport specialties to measure the capacity for short duration, high power output while cycling. The aim of this study was to establish differences in measuring anaerobic capacity between the classic Wingate test on a cycling ergometer and the modified Wingate test on a rowing ergometer in rowers. A group of20 rowers was tested by both the cycle and rowing ergometers during 30s of maximum power to test anaerobic capacity and to make correlation between these tests. The parameters measured were the peak power and mean power. The peak power on the cycling ergometer was 475 +/- 75.1W and 522.4 +/- 81W (p rowing ergometer. The mean power on the cycling ergometer and the rowing ergometer was 344.4 +/- 51.1W and 473.7W +/- 67.2, (p rowing ergometer. By correlating the anaerobic parameters of the classic Wingate test and a modified Wingate test on the rowing ergometer a significant positive correlation was detected in the peak power (r = 0.63, p rowing ergometer compared to the cycling ergometer due to a better mechanical efficiency. It is concluded that the modified Wingate test on the rowing ergometer can be used in rowers for testing their anaerobic capacity as a sport specific test ergometer since it provides more precise results.

  13. Recruitment of single muscle fibers during submaximal cycling exercise

    NARCIS (Netherlands)

    Altenburg, T.M.; Degens, H.; van Mechelen, W.; Sargeant, A.J.; de Haan, A.

    2007-01-01

    In literature, an inconsistency exists in the submaximal exercise intensity at which type II fibers are activated. In the present study, the recruitment of type I and II fibers was investigated from the very beginning and throughout a 45-min cycle exercise at 75% of the maximal oxygen uptake, which

  14. Physical efficiency and activity energy expenditure in term pregnancy females measured during cardiopulmonary exercise tests with a supine cycle ergometer.

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    Jędrzejko, Maciej; Nowosielski, Krzysztof; Poręba, Ryszard; Ulman-Włodarz, Izabela; Bobiński, Rafał

    2016-12-01

    To evaluate physical efficiency and activity energy expenditure (AEE) in term pregnancy females during cardiopulmonary exercise tests with a supine cycle ergometer. The study comprised 22 healthy full-term pregnancy women with uncomplicated pregnancies hospitalized in the Department of Gynecology and Obstetrics, Specialist Teaching Hospital in Tychy, Poland. All subjects underwent cardiopulmonary exercise tests (CPET) on a supine cycle ergometer. The 12-min, three-stage, progressive, symptom-limited submaximal test protocol (up to 80% HRmax) was used. Pulsometry was used to record HR on a beat-to-beat analysis and to calculate AEE. Respiratory responses were measured by ergospirometer and a computer system on a breath-by-breath basis at rest, during exercise and at restitution. In the studied population, VO2max was established at the level of 2.19 ± 0.33 L/min in ergospirometry and 2.04 ± 025 L/min in pulsometry. Physical efficiency calculated for sub-maximal exercise by use of the Davis equation was 30.52 ± 0.12%. AEE, based on VO2 in various phases of the CPET, was 0.47, 0.71 and 0.88 L/min for phases 25, 50 and 75 W. Based on ergospirometer readouts, AEE was 10.60, 16.11 and 20.94 kJ/min for phases 25, 50 and 75 W. Overall mean AEE (determined by pulsometry) was 10.59  kJ/min. CPET testing did not have any negative effect upon the health or life of the neonates involved in the study. Submaximal CPET up to 80% HRmax with a supine cycle ergometer is a safe and precise method for assessing work efficiency in term pregnancy women.

  15. A Systematic Review of Submaximal Cycle Tests to Predict, Monitor, and Optimize Cycling Performance.

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    Capostagno, Benoit; Lambert, Michael I; Lamberts, Robert P

    2016-09-01

    Finding the optimal balance between high training loads and recovery is a constant challenge for cyclists and their coaches. Monitoring improvements in performance and levels of fatigue is recommended to correctly adjust training to ensure optimal adaptation. However, many performance tests require a maximal or exhaustive effort, which reduces their real-world application. The purpose of this review was to investigate the development and use of submaximal cycling tests that can be used to predict and monitor cycling performance and training status. Twelve studies met the inclusion criteria, and 3 separate submaximal cycling tests were identified from within those 12. Submaximal variables including gross mechanical efficiency, oxygen uptake (VO2), heart rate, lactate, predicted time to exhaustion (pTE), rating of perceived exertion (RPE), power output, and heart-rate recovery (HRR) were the components of the 3 tests. pTE, submaximal power output, RPE, and HRR appear to have the most value for monitoring improvements in performance and indicate a state of fatigue. This literature review shows that several submaximal cycle tests have been developed over the last decade with the aim to predict, monitor, and optimize cycling performance. To be able to conduct a submaximal test on a regular basis, the test needs to be short in duration and as noninvasive as possible. In addition, a test should capture multiple variables and use multivariate analyses to interpret the submaximal outcomes correctly and alter training prescription if needed.

  16. Which factors determine the freely chosen cadence during submaximal cycling?

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    Vercruyssen, Fabrice; Brisswalter, Jeanick

    2010-03-01

    The present review of cycling science focuses on the identification of criteria that affect the freely chosen cadence (FCC) during submaximal exercise of short and prolonged durations. Cadence selection during submaximal cycling constitutes a potential parameter affecting the endurance performance in subjects of varying aerobic fitness level and experience. The activity constraints such as specificity (e.g. cycle bout of triathlon) and exercise duration may play an important role in the selection of cadence and must be taken into consideration in the task description. The 'holistic' approach of this review is based on a multifactorial analysis considering the cycling constraints, and the physiological and biomechanical factors of cadence selection so as to establish any interrelationships between these factors. During cycle bouts of short duration (<15 min), it has been well argued that experienced cyclists, trained runners and triathletes adopt high cadences (80-100 rpm) systematically above the energetically optimal cadence (EOC) at which the oxygen uptake is minimal (55-65 rpm). The choice of a high cadence has been shown to be dependent upon several factors, such as the aerobic fitness level, the reduction in forces applied to the cranks, the lower extremity net joint moments and minimal neuromuscular fatigue. However, with increasing exercise duration the FCC has been reported to be close to the EOC exclusively in endurance athletes practising a variety of activities, suggesting an impact of training mode on the muscular adaptations and the organisation of the movement pattern. Copyright 2009 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  17. Effects of music tempo upon submaximal cycling performance.

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    Waterhouse, J; Hudson, P; Edwards, B

    2010-08-01

    In an in vivo laboratory controlled study, 12 healthy male students cycled at self-chosen work-rates while listening to a program of six popular music tracks of different tempi. The program lasted about 25 min and was performed on three occasions--unknown to the participants, its tempo was normal, increased by 10% or decreased by 10%. Work done, distance covered and cadence were measured at the end of each track, as were heart rate and subjective measures of exertion, thermal comfort and how much the music was liked. Speeding up the music program increased distance covered/unit time, power and pedal cadence by 2.1%, 3.5% and 0.7%, respectively; slowing the program produced falls of 3.8%, 9.8% and 5.9%. Average heart rate changes were +0.1% (faster program) and -2.2% (slower program). Perceived exertion and how much the music was liked increased (faster program) by 2.4% and 1.3%, respectively, and decreased (slower program) by 3.6% and 35.4%. That is, healthy individuals performing submaximal exercise not only worked harder with faster music but also chose to do so and enjoyed the music more when it was played at a faster tempo. Implications of these findings for improving training regimens are discussed.

  18. Changes of heart rate variability and prefrontal oxygenation during Tai Chi practice versus arm ergometer cycling.

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    Lu, Xi; Hui-Chan, Christina Wan-Ying; Tsang, William Wai-Nam

    2016-11-01

    [Purpose] Exercise has been shown to improve cardiovascular fitness and cognitive function. Whether the inclusion of mind over exercise would increase parasympathetic control of the heart and brain activities more than general exercise at a similar intensity is not known. The aim of this study was to compare the effects of Tai Chi (mind-body exercise) versus arm ergometer cycling (body-focused exercise) on the heart rate variability and prefrontal oxygenation level. [Subjects and Methods] A Tai Chi master was invited to perform Tai Chi and arm ergometer cycling with similar exercise intensity on two separate days. Heart rate variability and prefrontal oxyhemoglobin levels were measured continuously by a RR recorder and near-infrared spectroscopy, respectively. [Results] During Tai Chi exercise, spectral analysis of heart rate variability demonstrated a higher high-frequency power as well as a lower low-frequency/high-frequency ratio than during ergometer cycling, suggesting increased parasympathetic and decreased sympathetic control of the heart. Also, prefrontal oxyhemoglobin and total hemoglobin levels were higher than those during arm ergometer exercise. [Conclusion] These findings suggest that increased parasympathetic control of the heart and prefrontal activities may be associated with Tai Chi practice. Having a "mind" component in Tai Chi could be more beneficial for older adults' cardiac health and cognitive function than body-focused ergometer cycling.

  19. Development and assessment of the Monark cycle ergometer for anaerobic muscular exercise

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    Frederick, F. A.; Langevin, R. C.; Miletti, J.; Sacco, M.; Murphy, M. M.

    1983-07-01

    This report describes the system developed by this Institute to measure anaerobic power production using the protocol developed at the Wingate Institute in Israel. This test consists of 30 seconds of maximal cycling (or cranking) exercise against a resistance determined according to the body weight of the subject. The system consists of a modified Monark cycle ergometer, a universal counter to monitor flywheel revolutions, and a desktop computer for timing, control, and data processing. The modification of the ergometer for the instantaneous application of resistance is presented. In addition, the methods used to measure pedal revolutions and to calibrate the ergometer, and the analysis of the forces acting on the flywheel are described. Finally, a description of the procedure used in the performance of the Wingate test and a summary of the actual data output are presented.

  20. Oxidative stress and immune system analysis after cycle ergometer use in critical patients

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    Eduardo Eriko Tenório de França

    Full Text Available OBJECTIVE: The passive cycle ergometer aims to prevent hypotrophy and improve muscle strength, with a consequent reduction in hospitalization time in the intensive care unit and functional improvement. However, its effects on oxidative stress and immune system parameters remain unknown. The aim of this study is to analyze the effects of a passive cycle ergometer on the immune system and oxidative stress in critical patients. METHODS: This paper describes a randomized controlled trial in a sample of 19 patients of both genders who were on mechanical ventilation and hospitalized in the intensive care unit of the Hospital Agamenom Magalhães. The patients were divided into two groups: one group underwent cycle ergometer passive exercise for 30 cycles/min on the lower limbs for 20 minutes; the other group did not undergo any therapeutic intervention during the study and served as the control group. A total of 20 ml of blood was analysed, in which nitric oxide levels and some specific inflammatory cytokines (tumour necrosis factor alpha (TNF-α, interferon gamma (IFN-γ and interleukins 6 (IL-6 and 10 (IL-10 were evaluated before and after the study protocol. RESULTS: Regarding the demographic and clinical variables, the groups were homogeneous in the early phases of the study. The nitric oxide analysis revealed a reduction in nitric oxide variation in stimulated cells (p=0.0021 and those stimulated (p=0.0076 after passive cycle ergometer use compared to the control group. No differences in the evaluated inflammatory cytokines were observed between the two groups. CONCLUSION: We can conclude that the passive cycle ergometer promoted reduced levels of nitric oxide, showing beneficial effects on oxidative stress reduction. As assessed by inflammatory cytokines, the treatment was not associated with changes in the immune system. However, further research in a larger population is necessary for more conclusive results.

  1. Effects of a Non-Circular Chainring on Sprint Performance During a Cycle Ergometer Test

    OpenAIRE

    Hintzy, Frédérique; Grappe, Frédéric; Belli, Alain

    2016-01-01

    Non-circular chainrings have been reported to alter the crank angular velocity profile over a pedal revolution so that more time is spent in the effective power phase. The purpose of this study was to determine whether sprint cycling performance could be improved using a non-circular chainring (Osymetric: ellipticity 1.25 and crank lever mounted nearly perpendicular to the major axis), in comparison with a circular chainring. Twenty sprint cyclists performed an 8 s sprint on a cycle ergometer...

  2. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer.

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    Alves-Pinto, Ana; Blumenstein, Tobias; Turova, Varvara; Lampe, Renée

    2016-01-01

    Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP). However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility. Electromyographic (EMG) recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions. Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist-antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation pattern correlated significantly with the degree of spasticity. This study confirmed the occurrence of altered lower leg muscle activation patterns in patients with CP during cycling on a recumbent ergometer. There is a need to develop feedback systems that can inform patients and therapists of an incorrect muscle activation during cycling and support the training of a more physiological activation

  3. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer

    Science.gov (United States)

    Alves-Pinto, Ana; Blumenstein, Tobias; Turova, Varvara; Lampe, Renée

    2016-01-01

    Objective Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP). However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility. Methods Electromyographic (EMG) recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions. Results Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist–antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation pattern correlated significantly with the degree of spasticity. Conclusion This study confirmed the occurrence of altered lower leg muscle activation patterns in patients with CP during cycling on a recumbent ergometer. There is a need to develop feedback systems that can inform patients and therapists of an incorrect muscle activation during cycling and support the training

  4. Changes of muscle torque after sprint and endurance training performed on the cycle ergometer

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    A Mastalerz

    2008-09-01

    Full Text Available The aim of this work was the specification of the influence of the sprint and endurance training performed on the cycle ergometer on changes of muscle torque. Forty three students of the Academy of Physical Education in Warsaw took part in the study. They were divided into 4 groups and performing the cycle ergometer training consisting of 5 intermittent efforts (2 min break: S10 group- the sprint training (maximal efforts performed with the 10% body weight load; S5 group- the sprint training (maximal efforts conducted with 5% body weight load; W80 group – endurance training (the effort power equal 250 W, single – 3 min effort equal 45 kJ, the pedalling rate – 80 rpm, load 31,0 N appended on the cycle ergometer scale; W45 group – endurance training (the effort power equal 250 W, single – 3 min effort equal 45 kJ, the pedalling rate 45 rpm, load 55.0 N appended on the cycle ergometer scale. The four - week sprint training conducted on the cycle ergometer elicited the increase of the torque of the hip extensors and flexors in S10 and S5 group; extensors of the knee joint in S5 group and plantar flexors in S10 group. The four week endurance training carried out on the cycle ergometer caused the increase of the torque of hip extensors in groups W80 and W45, extensors of the knee joint and plantar flexors in group W45 as well the lowering of the torque of hip flexors in W80 and W45 group and the knee joint flexors in all groups. The significant increase of the sum of the 5 examined muscle groups torque was observed after the sprint training only. Some significant differences between the sprint and endurance training considered hip flexors and the sum of 5 examined muscle groups torque. The endurance training elicited the significant decrease of an hip flexors-to-extensors index value in groups W80 and W45 and of the knee joint in group W45.

  5. Variability of Respiration and Metabolism: Responses to Submaximal Cycling and Running.

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    Armstrong, Lawrence E.; Costill, David L.

    1985-01-01

    This investigation examined day-to-day variations in metabolic measurements during submaximal running and cycling. Significant differences were found in the oxygen uptake (VO2) of runners and cyclists and the minute ventilation (VE) of cyclists while running, but blood lactic acid (HLA) did not differ day to day. (Author/MT)

  6. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer

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    Alves-Pinto A

    2016-06-01

    Full Text Available Ana Alves-Pinto,1,* Tobias Blumenstein,1,* Varvara Turova,1 Renée Lampe1,2 1Research Unit of the Buhl-Strohmaier Foundation for Cerebral Palsy and Paediatric Neuroorthopaedics, Orthopaedic Department, Klinikum rechts der Isar, 2Markus Würth Professorship, Technical University of Munich, Munich, Germany *These authors contributed equally to this work Objective: Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP. However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility.Methods: Electromyographic (EMG recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions.Results: Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist–antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation

  7. Air-braked cycle ergometers: validity of the correction factor for barometric pressure.

    Science.gov (United States)

    Finn, J P; Maxwell, B F; Withers, R T

    2000-10-01

    Barometric pressure exerts by far the greatest influence of the three environmental factors (barometric pressure, temperature and humidity) on power outputs from air-braked ergometers. The barometric pressure correction factor for power outputs from air-braked ergometers is in widespread use but apparently has never been empirically validated. Our experiment validated this correction factor by calibrating two air-braked cycle ergometers in a hypobaric chamber using a dynamic calibration rig. The results showed that if the power output correction for changes in air resistance at barometric pressures corresponding to altitudes of 38, 600, 1,200 and 1,800 m above mean sea level were applied, then the coefficients of variation were 0.8-1.9% over the range of 160-1,597 W. The overall mean error was 3.0 % but this included up to 0.73 % for the propagated error that was associated with errors in the measurement of: a) temperature b) relative humidity c) barometric pressure d) force, distance and angular velocity by the dynamic calibration rig. The overall mean error therefore approximated the +/- 2.0% of true load that was specified by the Laboratory Standards Assistance Scheme of the Australian Sports Commission. The validity of the correction factor for barometric pressure on power output was therefore demonstrated over the altitude range of 38-1,800 m.

  8. Reproducibility of incremental maximal cycle ergometer tests in healthy recreationally active subjects

    DEFF Research Database (Denmark)

    Dideriksen, Kasper; Mikkelsen, Ulla Ramer

    2015-01-01

    PURPOSE: Testing of the ventilatory threshold (VT) and maximal oxygen uptake (VO2 peak) is relevant for the evaluation of a range of training studies, clinical trials and cross-sectional studies. Due to a possible learning effect, a familiarization test is often performed to increase test......-averaging intervals (60, 30, 15, 10 and 5 s) for the determination of VO2 peak to compare test results and reproducibility. METHODS: Thirteen recreational triathletes completed three identical incremental maximal cycle ergometer tests. The initial workload was 75 and 100 watt (W) for women and men, respectively...

  9. MUSCLE FATIGUE INCREASES METABOLIC COSTS OF ERGOMETER CYCLING WITHOUT CHANGING VO2 SLOW COMPONENT

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    Aivaras Ratkevicius

    2006-09-01

    Full Text Available The aim of the present study was to investigate effects of muscle fatigue on oxygen costs of ergometer cycling and slow component of pulmonary oxygen uptake (VO2 kinetics. Seven young men performed 100 drop jumps (drop height of 40 cm with 20 s of rest after each jump. After the subsequent hour of rest, they cycled at 70, 105, 140 and 175 W, which corresponded to 29.6 ± 5.4, 39.4 ± 7.0, 50.8 ± 8.4 and 65.8 ± 11.8 % of VO2peak, respectively, for 6 min at each intensity with 4-min intervals of rest in between the exercise bouts. The VO2 response to cycling after the exercise (fatigue condition was compared to ergometer cycling without prior exercise (control condition. From 3rd to 6th min of cycling at 105, 140 and 175 W, VO2 was higher (p < 0.05-0.01 when cycling in the fatigue compared to the control condition. Slow component of VO2 kinetics was observed when cycling at 175 W in the control condition (0.17 ± 0.09, l·min-1, mean ± SD, but tended to decrease in the fatigue condition (0.13 ± 0.15 l·min-1. In summary, results of the study are in agreement with the hypothesis that muscle fatigue increases oxygen costs of cycling exercise, but does not affect significantly the slow component of pulmonary oxygen uptake (VO2 kinetics

  10. Optimal Resistive Forces for Maximizing the Reliability of Leg Muscles Capacities Tested on a Cycle Ergometer.

    Science.gov (United States)

    García-Ramos, Amador; Torrejón, Alejandro; Morales-Artacho, Antonio J; Pérez-Castilla, Alejandro; Jaric, Slobodan

    2017-09-27

    This study determined the optimal resistive forces for testing muscle capacities through the standard cycle ergometer test (one resistive force applied) and a recently developed two-point method (two resistive forces used for force-velocity modelling). Twenty-six men were tested twice on maximal sprints performed on a leg cycle ergometer against 5 flywheel resistive forces (R1-R5). The reliability of the cadence and maximum power measured against the 5 individual resistive forces, as well as the reliability of the force-velocity relationship parameters obtained from the selected two-point methods (R1-R2, R1-R3, R1-R4, and R1-R5) were compared. The reliability of outcomes obtained from individual resistive forces was high except for R5. As a consequence, the combination of R1 (≈175 rpm) and R4 (≈110 rpm) provided the most reliable two-point method (CV: 1.46%-4.04%; ICC: 0.89-0.96). Although the reliability of power capacity was similar for the R1-R4 two-point method (CV: 3.18%; ICC: 0.96) and the standard test (CV: 3.31%; ICC: 0.95), the two-point method should be recommended because it also reveals maximum force and velocity capacities. Finally, we conclude that the two-point method in cycling should be based on 2 distant resistive forces, but avoiding cadences below 110 rpm.

  11. Potentiation of sprint cycling performance: the effects of a high-inertia ergometer warm-up.

    Science.gov (United States)

    Munro, Lynne A; Stannard, Stephen R; Fink, Philip W; Foskett, Andrew

    2017-07-01

    Participant and protocol factors affect post-activation potentiation response. Performance enhancement is more consistent in highly-trained participants following multiple sets of a biomechanically similar conditioning activity. Providing optimal conditions, 6 international-level sprint cyclists executed multiple sets of short maximal conditioning contractions on a high-inertia ergometer before metered sprint performance. Three trial conditions were completed on separate days after a standardised warm-up: dynamic (DYN: 4 × 4 crank-cycles), isometric (ISO: 4 × 5-sec maximal voluntary contraction (MVC)), and control (CON: rest). Performance was measured from standing start to maximum velocity on an inertial-load ergometer at baseline (Pre), 4 (Post4), 8 (Post8) and 16 (Post16) min post-conditioning. Performance and biomechanical measures were assessed across 4 sprint segments, with magnitude-based inferences used to assess the likelihood that any affect was beneficial. Performance time only improved in DYN Post4, a 3.9% reduction during the first crank cycle (92% likely). On the ascending limb of the power-cadence relationship, peak torque and average power increased by 6.2% (94% likely) and 4.0% (87% likely), respectively. In ISOPost16, optimal cadence increased (82% likely) and average power improved over the descending limb (76% likely). DYN and ISO potentiated extremities of the torque-cadence relationship at distinct recovery times post-conditioning. This study suggests merit in including a high-inertia warm-up for sprint cycling.

  12. Effects of Beetroot Juice Supplementation on a 30-s High-Intensity Inertial Cycle Ergometer Test

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    Raul Domínguez

    2017-12-01

    Full Text Available Background: Beetroot juice (BJ is rich in inorganic nitrates and has proved effective at increasing blood nitric oxide (NO levels. When used as a supplement BJ has shown an ergogenic effect on cardiorespiratory resistance exercise modalities, yet few studies have examined its impact on high intensity efforts. Objective: To assess the effects of BJ intake on anaerobic performance in a Wingate test. Methods: Fifteen trained men (age 21.46 ± 1.72 years, height 1.78 ± 0.07 cm and weight 76.90 ± 8.67 kg undertook a 30-s maximum intensity test on an inertial cycle ergometer after drinking 70 mL of BJ (5.6 mmol NO3− or placebo. Results: Despite no impacts of BJ on the mean power recorded during the test, improvements were produced in peak power (6% (p = 0.034, average power 0–15 s (6.7% (p = 0.048 and final blood lactate levels (82.6% (p < 0.001, and there was a trend towards a shorter time taken to attain peak power (−8.4% (p = 0.055. Conclusions: Supplementation with BJ has an ergonomic effect on maximum power output and on average power during the first 15 s of a 30-s maximum intensity inertial cycle ergometer test.

  13. Effect of L-ornithine hydrochloride ingestion on intermittent maximal anaerobic cycle ergometer performance and fatigue recovery after exercise.

    Science.gov (United States)

    Demura, Shinichi; Morishita, Koji; Yamada, Takayoshi; Yamaji, Shunsuke; Komatsu, Miho

    2011-11-01

    L-Ornithine plays an important role in ammonia metabolism via the urea cycle. This study aimed to examine the effect of L-ornithine hydrochloride ingestion on ammonia metabolism and performance after intermittent maximal anaerobic cycle ergometer exercise. Ten healthy young adults (age, 23.8 ± 3.9 year; height, 172.3 ± 5.5 cm; body mass, 67.7 ± 6.1 kg) with regular training experience ingested L-ornithine hydrochloride (0.1 g/kg, body mass) or placebo after 30 s of maximal cycling exercise. Five sets of the same maximal cycling exercise were conducted 60 min after ingestion, and maximal cycling exercise was conducted after a 15 min rest. The intensity of cycling exercise was based on each subject's body mass (0.74 N kg(-1)). Work volume (watt), peak rpm (rpm) before and after intermittent maximal ergometer exercise and the following serum parameters were measured before ingestion, immediately after exercise and 15 min after exercise: ornithine, ammonia, urea, lactic acid and glutamate. Peak rpm was significantly greater with L-ornithine hydrochloride ingestion than with placebo ingestion. Serum ornithine level was significantly greater with L-ornithine hydrochloride ingestion than with placebo ingestion immediately and 15 min after intermittent maximal cycle ergometer exercise. In conclusion, although maximal anaerobic performance may be improved by L-ornithine hydrochloride ingestion before intermittent maximal anaerobic cycle ergometer exercise, the above may not depend on increase of ammonia metabolism with L-ornithine hydrochloride.

  14. Comparison of power output during ergometer and track cycling in adolescent cyclists.

    Science.gov (United States)

    Nimmerichter, Alfred; Williams, Craig A

    2015-04-01

    The aim of this study is to establish the level of agreement between test performance of young elite cyclists in a laboratory and a track field-based trial. Fourteen adolescent cyclists (age: 14.8 ± 1.1 years; (Equation is included in full-text article.): 63.5 ± 5.6 ml·min(-1)·kg(-1)) performed 3 tests of 10 seconds, 1 minute, and 3 minutes on an air-braked ergometer (Wattbike) and on a 250-m track using their own bikes mounted with mobile power meters (SRM). The agreement between the maximum and mean power output (Pmax and Pmean) measured on the Wattbike and SRM was assessed with the 95% limits of agreement (LoA). Power output was strongly correlated between Wattbike and SRM for all tests (r = 0.94-0.96; p track cycling during all tests. The bias and 95% LoA were 76 ± 78 W (8.8 ± 9.5%; p = 0.003, d = 0.38) for Pmax10s and 82 ± 55 W (10.9 ± 7.9%; p track field-based test using a mobile ergometer. These results might be attributed to the technical ability of the riders and their experience to optimize gearing and cadence to maximize performance. Prediction of field-based testing on the track from laboratory tests should be used with caution.

  15. Cycle ergometer and inspiratory muscle training offer modest benefit compared with cycle ergometer alone: a comprehensive assessment in stable COPD patients

    Directory of Open Access Journals (Sweden)

    Wang K

    2017-09-01

    Full Text Available Kai Wang,1,* Guang-qiao Zeng,2,* Rui Li,1,* Yu-wen Luo,1 Mei Wang,1 Yu-he Hu,1 Wen-hui Xu,1 Lu-qian Zhou,2 Rong-chang Chen,2 Xin Chen1 1Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China; 2Department of Respiratory Medicine, The State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China *These authors contributed equally to this work Background: Cycle ergometer training (CET has been shown to improve exercise performance of the quadriceps muscles in patients with COPD, and inspiratory muscle training (IMT may improve the pressure-generating capacity of the inspiratory muscles. However, the effects of combined CET and IMT remain unclear and there is a lack of comprehensive assessment.Materials and methods: Eighty-one patients with COPD were randomly allocated to three groups: 28 received 8 weeks of CET + IMT (combined training group, 27 received 8 weeks of CET alone (CET group, and 26 only received 8 weeks of free walking (control group. Comprehensive assessment including respiratory muscle strength, exercise capacity, pulmonary function, dyspnea, quality of life, emotional status, nutritional status, and body mass index, airflow obstruction, and exercise capacity index were measured before and after the pulmonary rehabilitation program.Results: Respiratory muscle strength, exercise capacity, inspiratory capacity, dyspnea, quality of life, depression and anxiety, and nutritional status were all improved in the combined training and CET groups when compared with that in the control group (P<0.05 after pulmonary rehabilitation program. Inspiratory muscle strength increased significantly in the combined training group when compared with that in the CET group (ΔPImax [maximal inspiratory pressure] 5.20±0.89 cmH2O vs 1.32±0.91 cmH2O

  16. Effects of Pedal Speed and Crank Length on Pedaling Mechanics during Submaximal Cycling

    Science.gov (United States)

    BARRATT, PAUL RICHARD; MARTIN, JAMES C.; ELMER, STEVE J.; KORFF, THOMAS

    2016-01-01

    ABSTRACT During submaximal cycling, the neuromuscular system has the freedom to select different intermuscular coordination strategies. From both a basic science and an applied perspective, it is important to understand how the central nervous system adjusts pedaling mechanics in response to changes in pedaling conditions. Purpose To determine the effect of changes in pedal speed (a marker of muscle shortening velocity) and crank length (a marker of muscle length) on pedaling mechanics during submaximal cycling. Methods Fifteen trained cyclists performed submaximal isokinetic cycling trials (90 rpm, 240 W) using pedal speeds of 1.41 to 1.61 m·s−1 and crank lengths of 150 to 190 mm. Joint powers were calculated using inverse dynamics. Results Increases in pedal speed and crank length caused large increases knee and hip angular excursions and velocities (P 0.05). Joint moments and joint powers were less affected by changes in the independent variables, but some interesting effects and trends were observed. Most noteworthy, knee extension moments and powers tended to decrease, whereas hip extension power tended to increase with an increase in crank length. Conclusions The distribution of joint moments and powers is largely maintained across a range of pedaling conditions. The crank length induced differences in knee extension moments, and powers may represent a trade-off between the central nervous system’s attempts to simultaneously minimize muscle metabolic and mechanical stresses. These results increase our understanding of the neural and mechanical mechanisms underlying multi-joint task performance, and they have practical relevance to coaches, athletes, and clinicians. PMID:26559455

  17. Slow volume changes in calf and thigh during cycle ergometer exercise.

    Science.gov (United States)

    Stick, C; Heinemann, W; Witzleb, E

    1990-01-01

    To study the transcapillary fluid movements in the human lower limb in the upright body position and during muscle exercise, the slow changes in thigh and calf volumes were measured by mercury-in-rubber-strain gauge plethysmography. Measurements were carried out on 20 healthy volunteers while sitting, standing and doing cycle ergometer exercise at intensities of 50 and 100-W. A plethysmographic recording of slow extravascular volume changes during muscle exercise was possible because movement artefacts were eliminated by low-pass filtering. While standing and sitting the volumes of both thigh and calf increased due to enhanced transcapillary filtration. While standing the mean rate of increase was 0.13%.min-1 in the calf and 0.09%.min-1 in the thigh. During cycle ergometer exercise at 50 and 100 W, the calf volume decreased with a mean rate of -0.09.min-1. In contrast, the thigh volume did not change significantly during exercise at 50 W and increased at 100 W. Most of the increase occurred during the first half of the experimental period i.e. between min 2 and 12, amounting to +0.6%. Thus, simultaneous measurements revealed opposite changes in the thigh and calf. This demonstrates that the conflicting findings reported in the literature may have occurred because opposite changes can occur in different muscle groups of the working limb at the same time. Lowered venous pressure, increased lymph flow and increased tissue pressure in the contracting muscle are considered to have caused the reduction in calf volume during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Effect of caffeine intake on critical power model parameters determined on a cycle ergometer

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    Marcus Vinicius Machado

    2010-01-01

    Full Text Available The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg or placebo (maltodextrin 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively. The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p< 0.01. A high association (r2 was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively. We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.

  19. Low-protein vegetarian diet does not have a short-term effect on blood acid–base status but raises oxygen consumption during submaximal cycling

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    Hietavala Enni-Maria

    2012-11-01

    Full Text Available Abstract Background Acid–base balance refers to the equilibrium between acids and bases in the human body. Nutrition may affect acid–base balance and further physical performance. With the help of PRAL (potential renal acid load, a low-protein vegetarian diet (LPVD was designed to enhance the production of bases in body. The aim of this study was to investigate if LPVD has an effect on blood acid–base status and performance during submaximal and maximal aerobic cycling. Methods Nine healthy, recreationally active men (age 23.5 ± 3.4 yr participated in the study and were randomly divided into two groups in a cross-over study design. Group 1 followed LPVD for 4 days and group 2 ate normally (ND before performing a cycle ergometer test. The test included three 10-min stages at 40, 60 and 80% of VO2max. The fourth stage was performed at 100% of VO2max until exhaustion. After 10–16 days, the groups started a second 4-day diet, and at the end performed the similar ergometer test. Venous blood samples were collected at the beginning and at the end of both diet periods and after every stage cycled. Results Diet caused no significant difference in venous blood pH, strong ion difference (SID, total concentration of weak acids (Atot, partial pressure of CO2 (pCO2 or HCO3- at rest or during cycling between LPVD and ND. In the LPVD group, at rest SID significantly increased over the diet period (38.6 ± 1.8 vs. 39.8 ± 0.9, p=0.009. Diet had no significant effect on exercise time to exhaustion, but VO2 was significantly higher at 40, 60 and 80% of VO2max after LPVD compared to ND (2.03 ± 0.25 vs. 1.82 ± 0.21 l/min, p=0.035; 2.86 ± 0.36 vs. 2.52 ± 0.33 l/min, p Conclusion There was no difference in venous blood acid–base status between a 4-day LPVD and ND. VO2 was increased during submaximal cycling after LPVD suggesting that the exercise economy was poorer. This had no further effect on maximal aerobic performance. More studies are needed to

  20. Different cycle ergometer outcomes in severely obese men and women without documented cardiopulmonary morbidities before bariatric surgery

    NARCIS (Netherlands)

    Dolfing, JG; Dubois, EF; Wolffenbuttel, BHR; ten Hoor-Aukema, NM; Schweitzer, DH

    Study objectives: The number of severely obese patients undergoing bariatric surgery is increasing. No incremental cycle ergometer data are available in this category of patients. The current study was undertaken to provide information and to compare outcomes between severely obese men and women

  1. Effect of Changes in Cycle Ergometer Settings on Bioelectrical Activity in Selected Muscles of the Lower Limbs

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    Staszkiewicz Robert

    2017-12-01

    Full Text Available Introduction. The aim of this study was to measure the duration of biopotentials in selected muscles of the lower limbs, evaluate the time of elevated bioelectrical activity in these muscles, and identify similarities and differences in electrical phenomena that occur in the muscles for various external settings of a cycle ergometer.

  2. Effects of modified electrical stimulation-induced leg cycle ergometer training for individuals with spinal cord injury

    NARCIS (Netherlands)

    Janssen, T.W.J.; Pringle, D.D.

    2008-01-01

    Computer-controlled electrical stimulation (ES)-induced leg cycle ergometer (ES-LCE) exercise can be beneficial for individuals with spinal cord injury (SCI), but exercise performance is often insufficient for eliciting continuous gains in cardiopulmonary training adaptations. The first purpose of

  3. Intensive cycle ergometer training improves gait speed and endurance in patients with Parkinson's disease: A comparison with treadmill training.

    Science.gov (United States)

    Arcolin, Ilaria; Pisano, Fabrizio; Delconte, Carmen; Godi, Marco; Schieppati, Marco; Mezzani, Alessandro; Picco, Daniele; Grasso, Margherita; Nardone, Antonio

    2015-01-01

    Cycle ergometer training improves gait in the elderly, but its effect in patients with Parkinson's disease (PD) is not completely known. Twenty-nine PD inpatients were randomized to treadmill (n = 13, PD-T) or cycle ergometer (n = 16, PD-C) training for 3 weeks, 1 hour/day. Outcome measures were distance travelled during the 6-min walking test (6MWT), spatio-temporal variables of gait assessed by baropodometry, the Timed Up and Go (TUG) duration, the balance score through the Mini-BESTest, and the score of the Unified Parkinson's Disease Rating Scale (UPDRS). Sex, age, body mass index, disease duration, Hoehn-Yahr staging, comorbidity and medication did not differ between groups. At end of training, ANCOVA showed significant improvement, of similar degree, in both groups for 6MWT, speed, step length and cadence of gait, TUG, Mini-BESTest and UPDRS. This pilot study shows that cycle ergometer training improves walking parameters and reduces clinical signs of PD, as much as treadmill training does. Gait velocity is accompanied by step lengthening, making the gait pattern close to that of healthy subjects. Cycle ergometer is a valid alternative to treadmill for improving gait in short term in patients with PD.

  4. Effects of a Non-Circular Chainring on Sprint Performance During a Cycle Ergometer Test

    Directory of Open Access Journals (Sweden)

    Frédérique Hintzy, Frédéric Grappe, Alain Belli

    2016-06-01

    Full Text Available Non-circular chainrings have been reported to alter the crank angular velocity profile over a pedal revolution so that more time is spent in the effective power phase. The purpose of this study was to determine whether sprint cycling performance could be improved using a non-circular chainring (Osymetric: ellipticity 1.25 and crank lever mounted nearly perpendicular to the major axis, in comparison with a circular chainring. Twenty sprint cyclists performed an 8 s sprint on a cycle ergometer against a 0.5 N/kg-1 friction force in four crossing conditions (non-circular or circular chainring with or without clipless pedal. Instantaneous force, velocity and power were continuously measured during each sprint. Three main characteristic pedal downstrokes were selected: maximal force (in the beginning of the sprint, maximal power (towards the middle, and maximal velocity (at the end of the sprint. Both average and instantaneous force, velocity and power were calculated during the three selected pedal downstrokes. The important finding of this study was that the maximal power output was significantly higher (+ 4.3%, p < 0.05 when using the non-circular chainring independent from the shoe-pedal linkage condition. This improvement is mainly explained by a significantly higher instantaneous external force that occurs during the downstroke. Non-circular chainring can have potential benefits on sprint cycling performance.

  5. Low doses of caffeine reduce heart rate during submaximal cycle ergometry

    Directory of Open Access Journals (Sweden)

    Wetter Thomas J

    2007-10-01

    Full Text Available Abstract Background The purpose of this study was to examine the cardiovascular effects of two low-levels of caffeine ingestion in non habitual caffeine users at various submaximal and maximal exercise intensities. Methods Nine male subjects (19–25 yr; 83.3 ± 3.1 kg; 184 ± 2 cm, underwent three testing sessions administered in a randomized and double-blind fashion. During each session, subjects were provided 4 oz of water and a gelatin capsule containing a placebo, 1.5 mg/kg caffeine, or 3.0 mg/kg caffeine. After thirty minutes of rest, a warm-up (30 Watts for 2 min the pedal rate of 60 rpm was maintained at a steady-state output of 60 watts for five minutes; increased to 120 watts for five minutes and to 180 watts for five minutes. After a 2 min rest the workload was 180 watts for one minute and increased by 30 watts every minute until exhaustion. Heart rate (HR was measured during the last 15-seconds of each minute of submaximal exercise. Systolic blood pressure (BP was measured at rest and during each of the three sub-maximal steady state power outputs. Minute ventilation (VE, Tidal volume (VT, Breathing frequency (Bf, Rating of perceived exertion (RPE, Respiratory exchange ratio (RER, and Oxygen consumption (VO2 were measured at rest and during each minute of exercise. Results Caffeine at 1.5 and 3.0 mg/kg body weight significantly lowered (p E, VT, VO2, RPE, maximal power output or time to exhaustion. Conclusion In non habitual caffeine users it appears that consuming a caffeine pill (1.5 & 3.0 mg/kg at a dose comparable to 1–3 cups of coffee lowers heart rate during submaximal exercise but not at near maximal and maximal exercise. In addition, this caffeine dose also only appears to affect systolic blood pressure at rest but not during cycling exercise.

  6. Effects of a Non-Circular Chainring on Sprint Performance During a Cycle Ergometer Test

    Science.gov (United States)

    Hintzy, Frédérique; Grappe, Frédéric; Belli, Alain

    2016-01-01

    Non-circular chainrings have been reported to alter the crank angular velocity profile over a pedal revolution so that more time is spent in the effective power phase. The purpose of this study was to determine whether sprint cycling performance could be improved using a non-circular chainring (Osymetric: ellipticity 1.25 and crank lever mounted nearly perpendicular to the major axis), in comparison with a circular chainring. Twenty sprint cyclists performed an 8 s sprint on a cycle ergometer against a 0.5 N/kg-1 friction force in four crossing conditions (non-circular or circular chainring with or without clipless pedal). Instantaneous force, velocity and power were continuously measured during each sprint. Three main characteristic pedal downstrokes were selected: maximal force (in the beginning of the sprint), maximal power (towards the middle), and maximal velocity (at the end of the sprint). Both average and instantaneous force, velocity and power were calculated during the three selected pedal downstrokes. The important finding of this study was that the maximal power output was significantly higher (+ 4.3%, p pedal linkage condition. This improvement is mainly explained by a significantly higher instantaneous external force that occurs during the downstroke. Non-circular chainring can have potential benefits on sprint cycling performance. Key points The Osymetric non-circular chainring significantly maximized crank power by 4.3% during sprint cycling, in comparison with a circular chainring. This maximal power output improvement was due to significant higher force developed when the crank was in the effective power phase. This maximal power output improvement was independent from the shoe-pedal linkage condition. Present benefits provided by the non-circular chainring on pedalling kinetics occurred only at high cadences. PMID:27274658

  7. Achilles tendinopathy alters stretch shortening cycle behaviour during a sub-maximal hopping task.

    Science.gov (United States)

    Debenham, James R; Travers, Mervyn J; Gibson, William; Campbell, Amity; Allison, Garry T

    2016-01-01

    To describe stretch shortening cycle behaviour of the ankle and lower limb in patients with Achilles tendinopathy (AT) and establish differences with healthy volunteers. Between-subjects case-controlled. Fifteen patients with AT (mean age 41.2±12.7 years) and 11 healthy volunteers (CON) (mean age 23.2±6.7 years) performed sub-maximal single-limb hopping on a custom built sledge-jump system. Using 3D motion analysis and surface EMG, temporal kinematic (lower limb stiffness, ankle angle at 80ms pre-contact, ankle angle at contact, peak ankle angle, ankle stretch amplitude) and EMG measures (onset, offset and peak times relative to contact) were captured. Data between AT and CON were compared statistically using a linear mixed model. Patients with AT exhibited significantly increased lower limb stiffness when compared to healthy volunteers (pbehaviour during sub-maximal hopping when compared with healthy volunteers. Patients with AT hop with greater lower limb stiffness, in a greater degree of ankle dorsiflexion and have a greater stretch amplitude. Likewise, delayed muscle activity is evident. These findings have implications in terms of informing the understanding of the pathoaetiology and management of AT. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  8. Slide-based ergometer rowing

    DEFF Research Database (Denmark)

    Vinther, Anders; Alkjær, T; Kanstrup, I-L

    2012-01-01

    Force production profile and neuromuscular activity during slide-based and stationary ergometer rowing at standardized submaximal power output were compared in 14 male and 8 female National Team rowers. Surface electromyography (EMG) was obtained in selected thoracic and leg muscles along with sy...

  9. Heart rate regulation during cycle-ergometer exercise via event-driven biofeedback.

    Science.gov (United States)

    Argha, Ahmadreza; Su, Steven W; Celler, Branko G

    2017-03-01

    This paper is devoted to the problem of regulating the heart rate response along a predetermined reference profile, for cycle-ergometer exercises designed for training or cardio-respiratory rehabilitation. The controller designed in this study is a non-conventional, non-model-based, proportional, integral and derivative (PID) controller. The PID controller commands can be transmitted as biofeedback auditory commands, which can be heard and interpreted by the exercising subject to increase or reduce exercise intensity. However, in such a case, for the purposes of effectively communicating to the exercising subject a change in the required exercise intensity, the timing of this feedback signal relative to the position of the pedals becomes critical. A feedback signal delivered when the pedals are not in a suitable position to efficiently exert force may be ineffective and this may, in turn, lead to the cognitive disengagement of the user from the feedback controller. This note examines a novel form of control system which has been expressly designed for this project. The system is called an "actuator-based event-driven control system". The proposed control system was experimentally verified using 24 healthy male subjects who were randomly divided into two separate groups, along with cross-validation scheme. A statistical analysis was employed to test the generalisation of the PID tunes, derived based on the average transfer functions of the two groups, and it revealed that there were no significant differences between the mean values of root mean square of the tracking error of two groups (3.9 vs. 3.7 bpm, [Formula: see text]). Furthermore, the results of a second statistical hypothesis test showed that the proposed PID controller with novel synchronised biofeedback mechanism has better performance compared to a conventional PID controller with a fixed-rate biofeedback mechanism (Group 1: 3.9 vs. 5.0 bpm, Group 2: 3.7 vs. 4.4 bpm, [Formula: see text]).

  10. The Cross-Validation of the United States Air Force Submaximal Cycle Ergometer Test to Estimate Aerobic Capacity

    Science.gov (United States)

    1994-06-01

    Technology Division 2504 D Drive, Suite 1 AL/CF-TR-1994-0046 Arooks Air Force Base- ,TX 78235-5104 11. SUPPLEMENTARY NOTES Armstrong Laboratory...0Ahm" II u . )00 LL • ,I * I* I o,- ’ r4 -. r-CR nN6 %i q -1 -c t- *N oo C21, %0V 0%a Mtl 00t No 0 o w 0 c. C6 00 -0-O0’- 0 . C 0*hs r I IF S.p El No...pressure, and breathing will be monitored. You will wear headgear with an attached mouthpiece to monitor your breathing. You will also wear electrodes to

  11. Live high:train low increases muscle buffer capacity and submaximal cycling efficiency.

    Science.gov (United States)

    Gore, C J; Hahn, A G; Aughey, R J; Martin, D T; Ashenden, M J; Clark, S A; Garnham, A P; Roberts, A D; Slater, G J; McKenna, M J

    2001-11-01

    This study investigated whether hypoxic exposure increased muscle buffer capacity (beta(m)) and mechanical efficiency during exercise in male athletes. A control (CON, n=7) and a live high:train low group (LHTL, n=6) trained at near sea level (600 m), with the LHTL group sleeping for 23 nights in simulated moderate altitude (3000 m). Whole body oxygen consumption (VO2) was measured under normoxia before, during and after 23 nights of sleeping in hypoxia, during cycle ergometry comprising 4 x 4-min submaximal stages, 2-min at 5.6 +/- 0.4 W kg(-1), and 2-min 'all-out' to determine total work and VO(2peak). A vastus lateralis muscle biopsy was taken at rest and after a standardized 2-min 5.6 +/- 0.4 W kg(-1) bout, before and after LHTL, and analysed for beta(m) and metabolites. After LHTL, beta(m) was increased (18%, P buffer capacity. Further, reduced VO2 during normoxic exercise after LHTL suggests that improved exercise efficiency is a fundamental adaptation to LHTL.

  12. Different cycle ergometer outcomes in severely obese men and women without documented cardiopulmonary morbidities before bariatric surgery.

    Science.gov (United States)

    Dolfing, Jacqueline G; Dubois, Emile F; Wolffenbuttel, Bruce H R; ten Hoor-Aukema, Nienke M; Schweitzer, Dave H

    2005-07-01

    The number of severely obese patients undergoing bariatric surgery is increasing. No incremental cycle ergometer data are available in this category of patients. The current study was undertaken to provide information and to compare outcomes between severely obese men and women during physical exercise. Cross-sectional study. Twenty-two men and 34 women, all with a body mass index (BMI) of at least 40 kg/m(2), were selected from among persons participating in a dedicated weight management program that was carried out in the outpatient clinic of a large teaching hospital. Body composition was estimated with bioelectrical impedance. Oxygen uptake (Vo(2)) was obtained by breath-by-breath minute ventilation (ventilated hood) and was measured under resting energy expenditure (REE) conditions. Endurance was measured with an incremental cycle ergometer test. Male and female groups were balanced for mean (+/- SD) age (42.7 +/- 7.6 vs 41.8 +/- 8.9 years, respectively), BMI (43.0 +/- 4.9 vs 41.3 +/- 5.2 kg/m(2), respectively), and fat weight (55.5 +/- 14.0 vs 56.8 +/- 2.2 kg, respectively). Fat-free mass (FFM), FFM index, fasting blood glucose level, insulin level, REE, and Vo(2) at rest and during subjective maximal endurance were higher in the male group. However, maximal Vo(2) (women, 119 +/- 19% predicted; men, 92 +/- 16% predicted) and anaerobic threshold were higher in the female group (women, 64 +/- 12% predicted; men, 48 +/- 76% predicted, respectively; p endurance than was predicted according to standards in comparison with obese women. The cycle ergometer data indicated that male gender was associated with less physical fitness.

  13. Design of a web-based health promotion system and its practical implementation for cycle ergometer exercise.

    Science.gov (United States)

    Wang, Z; Kiryu, T

    2004-01-01

    Health promotion is a very active topic in recent years. Most people want to exercise regularly, but there are various obstacles to keep staying motivated in their busy life today. In this paper, we propose a system design on a proven enterprise architecture that aims to support in constituting a comprehensive infrastructure for a wellness exercise environment. The design extends normal health promotion model to address cost-efficient and forward-looking for future health industry. Moreover, web-based technology has been widely adopted to implement a platform-nature solution in a heterogeneous computing environment based on the Internet. In particular, a Self-describing strategy for effectively developing and deploying exercise programs has been originally proposed and contrived. By applying the design to cycle ergometer exercise, we presented a practical exercise system realizing easy-to-use operation interfaces on a web browser. The web-based cycle ergometer exercise system was proved to be workable in our feasibility experiments.

  14. Oxygen uptake in water polo, comparison and agreement in cycle ergometer and eggbeater kick: A pilot study

    Directory of Open Access Journals (Sweden)

    Ligia Ignêz Engelmann

    Full Text Available Abstract The aim of this study was to compare and verify the agreement of maximal oxygen uptake (VO2 max values obtained from tests on land and in water. Twelve recreational water polo players (30.5 ± 7.7 years; 79.2 ± 7.2 kg body mass; 179.1 ± 5.9 cm height were assessed in two phases: (1 in laboratory with maximal test on a cycle ergometer and (2 in a swimming pool with maximal test in eggbeater kick. Maximum values obtained in the two tests (respectively, cycle ergometer, and eggbeater kick: VO2 max = 40.2 ± 2.7 ml.kg-1.min-1 and 38.4 ± 5.7 ml.kg-1.min-1; RER = 1.17 ± 0.08 and 1.19 ± 0.12; HR max = 181.4 ± 11.7 bpm and 179 ± 11.7 bpm; IEP = 20 and 20 did not show significant differences. According to the Bland-Altman analyses, there were acceptable limits of agreement between the two tests (land and water. Therefore, it can be concluded that the eggbeater kick test is a specific and valid protocol to asses VO2 max in water polo players.

  15. Effect of chain wheel shape on crank torque, freely chosen pedal rate, and physiological responses during submaximal cycling

    DEFF Research Database (Denmark)

    Hansen, Ernst Albin; Jensen, Kurt; Hallén, Jostein

    2009-01-01

    . A musculoskeletal simulation model supported the idea that a contributing factor to the observed difference in blood lactate concentration may be slightly reduced muscle activity around the phase where peak crank torque occurs during cycling with the Biopace chain wheel. In that particular phase of the crank......The development of noncircular chain wheels for the enhancement of cycling performance has been in progress for a long time and continues apace. In this study we tested whether submaximal cycling using a non-circular (Biopace) versus a circular chain wheel resulted in lower peak crank torque...... chain wheel at 180 W at 65 and 90 rpm for recording of crank torque profiles, and at their freely chosen pedal rate for recording of pedal rate and metabolic response, including oxygen uptake and blood lactate concentration. Crank torque profiles were similar between the two chain wheels during cycling...

  16. Ergometer rowing with and without slides

    DEFF Research Database (Denmark)

    Larsen, Anders Holsgaard; Jensen, K

    2010-01-01

    A rowing ergometer can be placed on a slide to imitate 'on-water' rowing. The present study examines I) possible differences in biomechanical and physiological variables of ergometer rowing with and without slides and II) potential consequences on training load during exercise. 7 elite oars......-women rowed in a randomized order in a slide or stationary ergometer at 3 predefined submaximal and at maximal intensity. Oxygen uptake was measured and biomechanical variables of the rowing were calculated based upon handle force (force transducer) and velocity/length (potentiometer) of the stroke. Stroke...

  17. Comparison of VO[subscript 2] Maximum Obtained from 20 m Shuttle Run and Cycle Ergometer in Children with and without Developmental Coordination Disorder

    Science.gov (United States)

    Cairney, John; Hay, John; Veldhuizen, Scott; Faught, Brent

    2010-01-01

    Oxygen consumption at peak physical exertion (VO[subscript 2] maximum) is the most widely used indicator of cardiorespiratory fitness. The purpose of this study was to compare two protocols for its estimation, cycle ergometer testing and the 20 m shuttle run, among children with and without probable developmental coordination disorder (pDCD). The…

  18. Exposure to a combination of heat and hyperoxia during cycling at submaximal intensity does not alter thermoregulatory responses

    Directory of Open Access Journals (Sweden)

    C Zinner

    2016-02-01

    Full Text Available In this study, we tested the hypothesis that breathing hyperoxic air (FinO2 = 0.40 while exercising in a hot environment exerts negative effects on the total tissue level of haemoglobin concentration (tHb; core (Tcore and skin (Tskin temperatures; muscle activity; heart rate; blood concentration of lactate; pH; partial pressure of oxygen (PaO2 and carbon dioxide; arterial oxygen saturation (SaO2; and perceptual responses. Ten well-trained male athletes cycled at submaximal intensity at 21°C or 33°C in randomized order: first for 20 min while breathing normal air (FinO2 = 0.21 and then 10 min with FinO2 = 0.40 (HOX. At both temperatures, SaO2 and PaO2, but not tHb, were increased by HOX. Tskin and perception of exertion and thermal discomfort were higher at 33°C than 21°C (p 0.07. Blood lactate and heart rate were higher at 33°C than 21°C. In conclusion, during 30 min of submaximal cycling at 21°C or 33°C, Tcore, Tskin and Tbody, tHb, muscle activity and ratings of perceived exertion and thermal discomfort were the same under normoxic and hyperoxic conditions. Accordingly, breathing hyperoxic air (FinO2 = 0.40 did not affect thermoregulation under these conditions.

  19. In vivo hip joint loads and pedal forces during ergometer cycling.

    Science.gov (United States)

    Damm, P; Dymke, J; Bender, A; Duda, G; Bergmann, G

    2017-07-26

    The rising prevalence of osteoarthritis and an increase in total hip replacements calls for attention to potential therapeutic activities. Cycling is considered as a low impact exercise for the hip joint and hence recommended. However, there are limited data about hip joint loading to support this claim. The aim of this study was to measure synchronously the in vivo hip joint loads and pedal forces during cycling. The in vivo hip joint loads were measured in 5 patients with instrumented hip implants. Data were collected at several combinations of power and cadence, at two saddle heights. Joint loads and pedal forces showed strong linear correlation with power. So the relationship between the external pedal forces and internal joint forces was shown. While cycling at different cadences the minimum joint loads were acquired at 60RPM. The lower saddle height configuration results in an approximately 15% increase compared to normal saddle height. The results offered new insights into the actual effects of cycling on the hip joint and can serve as useful tools while developing an optimum cycling regimen for individuals with coxarthrosis or following total hip arthroplasty. Due to the relatively low contact forces, cycling at a moderate power level of 90W at a normal saddle height is suitable for patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Cycling on rollers: Kreitler fan resistance at submaximal levels of effort.

    Science.gov (United States)

    Reiser, R F; Hart, C R

    2008-03-01

    The goal of this investigation was to characterize the commercially available fan unit for the KreitlerAlloy rollers at submaximal levels of effort (cyclist rode six times at each of three fan inlet settings (closed, half, and full open) and five fan speeds (900, 1800, 2700, 3600, and 4500 rpm). Fan power requirements were isolated by subtracting roller resistance from separate trials. Power requirements relative to fan inlet and fan speed possessed a significant interaction with the main effects for each also significant (all p or = 0.997). Fan resistance was virtually non existent at 900 rpm. Fan resistance then significantly increased with increasing fan speed and inlet opening. At 4500 rpm power requirements of the fan reached 269 +/- 6, 352 +/- 7, and 406 +/- 9 W with the inlet closed, half, and fully open, respectively (p training and testing environments.

  1. Lactate and ammonia concentration in blood and sweat during incremental cycle ergometer exercise

    NARCIS (Netherlands)

    Ament, W; Huizenga, [No Value; Mook, GA; Gips, CH; Verkerke, GJ

    It is known that the concentrations of ammonia and lactate in blood increase during incremental exercise. Sweat also contains lactate and ammonia. The aim of the present study was to investigate the physiological response of lactate and ammonia in plasma and sweat during a stepwise incremental cycle

  2. Heavy strength training improves running and cycling performance following prolonged submaximal work in well-trained female athletes.

    Science.gov (United States)

    Vikmoen, Olav; Rønnestad, Bent R; Ellefsen, Stian; Raastad, Truls

    2017-03-01

    The purpose of this study was to investigate the effects of adding heavy strength training to female duathletes' normal endurance training on both cycling and running performance. Nineteen well-trained female duathletes ( V O 2max cycling: 54 ± 3 ml∙kg -1 ∙min -1 , VO 2max running: 53 ± 3 ml∙kg -1 ∙min -1 ) were randomly assigned to either normal endurance training ( E , n  = 8) or normal endurance training combined with strength training ( E+S , n  = 11). The strength training consisted of four lower body exercises [3 × 4-10 repetition maximum (RM)] twice a week for 11 weeks. Running and cycling performance were assessed using 5-min all-out tests, performed immediately after prolonged periods of submaximal work (3 h cycling or 1.5 h running). E+S increased 1RM in half squat (45 ± 22%) and lean mass in the legs (3.1 ± 4.0%) more than E Performance during the 5-min all-out test increased in both cycling (7.0 ± 4.5%) and running (4.7 ± 6.0%) in E+S, whereas no changes occurred in E The changes in running performance were different between groups. E+S reduced oxygen consumption and heart rate during the final 2 h of prolonged cycling, whereas no changes occurred in E No changes occurred during the prolonged running in any group. Adding strength training to normal endurance training in well-trained female duathletes improved both running and cycling performance when tested immediately after prolonged submaximal work. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  3. External And Internal Work Of A T-6 Paraplegic Propelling A Wheelchair And Arm Cranking A Cycle Ergometer: Case Study

    Science.gov (United States)

    Novak, Charles W.

    1982-02-01

    In this, the International Year of the Disabled, attention is directed among other areas toward rehabilitation and sports participation of wheelchair users. As an application of movement analysis in medicine and rehabilitation and as an application of sports research using biomechanics, this investigation was performed to compare the results of two methods of gathering data on the stress of wheelchair propelling at equivalent work loads and to account for differences in physiological responses with a mechanical analysis of wheelchair propelling. Physiological data collected were heart rate, systolic blood pressure, and rate-pressure product. A biomechanical cinematography analysis was used to determine external work in wheelchair propelling and to determine the extent to which modifications in segment actionsoccurred during increasing magnitude of work. A cycle ergometer was adjusted to replicate external work loads performed during wheelchair propelling. A t-test of equivalent external work loads indicated that heart rate was not different between the two exercise modes at the .05 level of significance. The t-test did indicate a significant difference in systolic blood pressure and rate-pressure product at the .05 level of significance. The biomechanical analysis of wheelchair propelling established that an increase in external work was accomplished by a decrease in the range of motion and an increase in the speed of movement. During cycle ergometry the range and speed of movement remained the same while resistance was increased. Results of the study established that while heart rate for equivalent external work loads was the same for wheelchair propelling and arm cranking cycle ergometry, systolic blood pressure and rate-pressure product were not the same. The suggestion was that some means of propelling a wheelchair other than that which is con-sidered "standard" might be considered which produces less stressful responses in wheelchair users.

  4. Effects of Ramadan observance on repeated cycle ergometer sprinting and associated inflammatory and oxidative stress responses in trained young men

    Directory of Open Access Journals (Sweden)

    Hatem Bouhlel

    2016-03-01

    Full Text Available Aim: was to assess the effects of Ramadan observance upon repeated sprints and associated inflammatory and oxidative stress responses. Methods: Ten young trained boxers were tested during a control period (C, at the end of the first week (R-1, and during the fourth week of Ramadan observance (R-4. On each occasion, they performed three vertical jumps, 10 x 6 s repeated sprints on a cycle ergometer, followed by three final vertical jumps 1 min after. Surface electrodes measured the EMG activity of the vastus lateralis during jumps performed before and after sprinting. Oxidative stress (malondialdehyde, total antioxidant and catalase, inflammatory markers (C-reactive protein, Interleukin-6 and homocysteine, muscle damage (CPK and LDH and blood glucose were measured at rest and after completing the exercise protocol. Results: The overall sprint performance was reduced at R-1 compared to C (-6.3 ± 1.2%, p = 0.025, but had recovered by R-4. Jump height decreased after the repeated sprints (p

  5. Reliability of Upright and Supine Power Measurements Using an Inertial Load Cycle Ergometer

    Science.gov (United States)

    Wickwire, P. J.; Leach, M.; Ryder, J.; Ploutz-Snyder, R.; Ploutz-Snyder, L.

    2011-01-01

    Practical, reliable, and time efficient methods of measuring muscular power are desirable for both research and applied testing situations. The inertial-load cycling method (ILC; Power/Cycle, Austin, TX) requires subjects to pedal as fast as possible against the inertial load of a flywheel for only 3-5 seconds, which could help reduce the time and effort required for maximal power testing. PURPOSE: 1) To test the intramachine reliability of ILC over 3 separate sessions, 2) to compare postural stance (upright vs. supine) during testing, and 3) to compare the maximal power (Pmax) output measured using ILC to that obtained from traditional isokinetic and leg press testing. METHODS: Subjects (n = 12) were tested on 4 non-consecutive days. The following tests were done on the first day of testing: isometric knee extension, isokinetic knee extension at several speeds, isokinetic power/endurance at 180/sec (Biodex System 4), leg press maximal isometric force, and leg press power/endurance. The other 3 days consisted exclusively of ILC testing. Subjects performed 6 ILC tests in an upright position and 6 ILC tests in a supine position on each day. The starting position was counterbalanced. Mixed-effects linear modeling was used to determine if any differences existed between testing days and between upright and supine for Pmax and revolutions per minute at Pmax (RPMpk). Mixed-modeling was also used to calculate intraclass correlation coefficients (ICC) to determine the reliability of the ILC on each testing day for Pmax and RPMpk (ICCs were calculated separately for upright and supine). gKendall fs Tau a h was used to determine the association between ILC Pmax and isokinetic and leg press data. RESULTS: For Pmax, significant differences were found between days 1 and 2 (upright: p = 0.018; supine: p = 0.014) and between days 1 and 3 (upright: p = 0.001; supine: p = 0.002), but not between days 2 and 3 (upright: p = 0.422; supine: p = 0.501). Pmax ICC values were greater than

  6. Modeling trajectories of perceived leg exertion during maximal cycle ergometer exercise in children and adolescents.

    Science.gov (United States)

    Huebner, Marianne; Zhang, Zhen; Therneau, Terry; McGrath, Patrick; Pianosi, Paolo

    2014-01-09

    Borg developed scales for rating pain and perceived exertion in adults that have also been used in pediatric populations. Models describing functional relationships between perceived exertion and work capacity have not been studied in children. We compared different models and their fits to individual trajectories and assessed the variability in these trajectories. Ratings of perceived exertion (RPE) were collected from 79 children. Progressive cycle ergonometric testing was performed to maximal work capacity with test duration ranging from 6- 12 minutes. Ratings were obtained during each 1-minute increment. Work was normalized to individual maximal work capacity (Wmax). A delay was defined as the fraction of Wmax at which point an increase in ratings of leg fatigue occurred. Such a delay term allows the characterization of trajectories for children whose ratings were initially constant with increasing work. Two models were considered, a delay model and a power model that is commonly used to analyze Borg ratings. Individual model fit was assessed with root mean squared error (RMSE). Functional clustering algorithms were used to identify patterns. Leg tiredness developed quickly for some children while for others there was a delay before an in- creased ratings of leg exertion occurred with increasing work. Models for individual trajectories with the smallest RMSE included a delay and a quadratic term (quadratic-delay model), or a power function and a delay term (power-delay model) compared to a simple power function. The median delay was 40% Wmax (interquartile range (IQR): 26-49%) in a quadratic-delay model, while the median exponent was 1.03 (IQR: 0.83-1.78) in a power-delay model. Nine clusters were identified showing linear or quadratic patterns with or without a delay. Cluster membership did not depend on age, gender or diagnosis. Children and adolescents vary widely in their capacity to rate their perceptions and exhibit different functional relationships

  7. Maximal Oxygen Uptake cannot be Determined in the Incremental Phase of The Lactate Minimum Test on a Cycle Ergometer

    Directory of Open Access Journals (Sweden)

    Willian Eiji Miyagi, Elvis de Souza Malta, Alessandro Moura Zagatto

    2015-06-01

    Full Text Available The aim of this study was to investigate the maximal oxygen uptake (VO2MAX determined using the incremental phase of the lactate minimum test (LM on a cycle ergometer. Fifteen trained men were submitted to a graded exercise test (GXT to evaluate the VO2MAX and LM. The total durations of the GXT and LM were 11.2±1.8 minutes (CI95%:10.2-12.3 minutes and 25.3±3.2 minutes (CI95%:23.5-27.0, respectively. For the variables measured at exhaustion in both the GXT and LM, the oxygen uptake (54.6 ± 8.1 ml·kg−1·min−1vs 50.0 ± 7.7 ml·kg−1·min−1, carbon dioxide production (66.1 ± 7.5 ml·kg−1·min−1 vs 50.4 ± 8.0 ml·kg−1·min−1, ventilation (153.9 ± 19.0 L·min−1 vs 129.9 ± 22.9 L·min−1, respiratory exchange ratio (1.22 ± 0.10 vs1.01 ± 0.05, maximal power output achieved (331.6 ± 45.8 W vs 242.4 ± 41.0 W, heart rate (183.1 ± 6.9 bpm vs175.9 ± 10.6 bpm and lactate (10.5 ± 2.3 mmol·L−1 vs 6.6 ± 2.2 mmol·L−1 were statistically lower in the LM (p < 0.05. However, the values of rating of perceived exertion (17.6 ± 2.5 for GXT and 17.2 ± 2.3 for LM did not differ (ES = 0.12 and CV = 7.8%. There was no good agreement between the values of the VO2MAX from the GXT and VO2PEAK from the LM, as evidenced in the Bland-Altman plot (4.7 ml·kg−1·min−1 and 0.34 L·min−1 of mean differences, respectively, as well as the high values of the upper and lower limits of agreement. We conclude that the VO2PEAK values obtained in the incremental phase of the LM underestimate the VO2MAX.

  8. Mechanical muscle properties and intermuscular coordination in maximal and submaximal cycling: theoretical and practical implications

    OpenAIRE

    Barratt, Paul

    2014-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University The ability of an individual to perform a functional movement is determined by a range of mechanical properties including the force and power producing capabilities of muscle, and the interplay of force and power outputs between different muscle groups (intermuscular coordination). Cycling presents an ideal experimental model to investigate these factors as it is an ecologically valid multi-jo...

  9. Ergometer rowing with and without slides.

    Science.gov (United States)

    Holsgaard-Larsen, A; Jensen, K

    2010-12-01

    A rowing ergometer can be placed on a slide to imitate 'on-water' rowing. The present study examines I) possible differences in biomechanical and physiological variables of ergometer rowing with and without slides and II) potential consequences on training load during exercise. 7 elite oars-women rowed in a randomized order in a slide or stationary ergometer at 3 predefined submaximal and at maximal intensity. Oxygen uptake was measured and biomechanical variables of the rowing were calculated based upon handle force (force transducer) and velocity/length (potentiometer) of the stroke. Stroke frequency was higher (%-difference between conditions) at each intensity level (1-11.4%, prowing. Furthermore, at the 2 highest intensities a lower mean force (4.7-9.0%, prowing no difference was seen in heart rate, mean oxygen uptake and R-value while maximal oxygen deficit was higher (30.8%, prowing. In conclusion the biomechanical load is lower on a slide than on a stationary ergometer. However, as a training tool the slide ergometer seems just as demanding with regard to aerobic energy sources, and for anaerobic sources possibly even higher, compared with the stationary ergometer. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Mechanisms underlying enhancements in muscle force and power output during maximal cycle ergometer exercise induced by chronic β2-adrenergic stimulation in men

    DEFF Research Database (Denmark)

    Hostrup, Morten; Kalsen, Anders; Onslev, Johan

    2015-01-01

    The study was a randomized placebo-controlled trial investigating mechanisms by which chronic β2-adrenergic stimulation enhances muscle force and power output during maximal cycle ergometer exercise in young men. Eighteen trained men were assigned to an experimental group (oral terbutaline 5 mg∙30...... output during 30-s of maximal cycling increased (P≤0.01) by 32±8 and 25±9 W, respectively, with the intervention in TER compared to PLA. Maximal oxygen consumption (V̇o2 max) and time to fatigue during incremental cycling did not change with the intervention. Lean body mass increased by 1.95±0.8 kg (P≤0...... and peak power during maximal cycling induced by chronic β2-adrenergic stimulation in humans....

  11. Maximal Oxygen Uptake cannot be Determined in the Incremental Phase of The Lactate Minimum Test on a Cycle Ergometer.

    Science.gov (United States)

    Miyagi, Willian Eiji; Malta, Elvis de Souza; Zagatto, Alessandro Moura

    2015-06-01

    The aim of this study was to investigate the maximal oxygen uptake (VO2MAX) determined using the incremental phase of the lactate minimum test (LM) on a cycle ergometer. Fifteen trained men were submitted to a graded exercise test (GXT) to evaluate the VO2MAX and LM. The total durations of the GXT and LM were 11.2±1.8 minutes (CI95%:10.2-12.3 minutes) and 25.3±3.2 minutes (CI95%:23.5-27.0), respectively. For the variables measured at exhaustion in both the GXT and LM, the oxygen uptake (54.6 ± 8.1 ml·kg(-1)·min(-1) vs 50.0 ± 7.7 ml·kg(-1)·min(-1)), carbon dioxide production (66.1 ± 7.5 ml·kg(-1)·min(-1) vs 50.4 ± 8.0 ml·kg(-1)·min(-1)), ventilation (153.9 ± 19.0 L·min(-1) vs 129.9 ± 22.9 L·min(-1)), respiratory exchange ratio (1.22 ± 0.10 vs1.01 ± 0.05), maximal power output achieved (331.6 ± 45.8 W vs 242.4 ± 41.0 W), heart rate (183.1 ± 6.9 bpm vs175.9 ± 10.6 bpm) and lactate (10.5 ± 2.3 mmol·L(-1) vs 6.6 ± 2.2 mmol·L(-1)) were statistically lower in the LM (p < 0.05). However, the values of rating of perceived exertion (17.6 ± 2.5 for GXT and 17.2 ± 2.3 for LM) did not differ (ES = 0.12 and CV = 7.8%). There was no good agreement between the values of the VO2MAX from the GXT and VO2PEAK from the LM, as evidenced in the Bland-Altman plot (4.7 ml·kg(-1)·min(-1) and 0.34 L·min(-1) of mean differences, respectively), as well as the high values of the upper and lower limits of agreement. We conclude that the VO2PEAK values obtained in the incremental phase of the LM underestimate the VO2MAX. Key pointsThe VO2MAX is not attained during the incremental phase of the lactate minimum test;The physiological responses at exhaustion during LM are not similar to physiological responses measured during GXT;There is a weak agreement between the peak VO2 measured at exhaustion during LM and the VO2MAX measured during GXT.

  12. Changes in Oxyhemoglobin Concentration in the Prefrontal Cortex and Primary Motor Cortex During Low- and Moderate-Intensity Exercise on a Cycle Ergometer.

    Science.gov (United States)

    Takehara, Nana; Tsubaki, Atsuhiro; Yamazaki, Yudai; Kanaya, Chiaki; Sato, Daisuke; Morishita, Shinichiro; Onishi, Hideaki

    2017-01-01

    The present study investigated whether changes in oxyhemoglobin (O2Hb) concentration over time differed across brain regions according to differences in gross movement intensity. Thirteen healthy adults (21.2 ± 1.0 years, 8 women) participated in this study. After 180 s of rest, the participants performed 600 s of exercise on a cycle ergometer. Exercise intensity was set at 30%VO2peak and 50%VO2peak. The prefrontal cortex (PFC) and primary motor cortex (M1) were chosen as regions of interest. In addition, mean arterial pressure (MAP) and scalp blood flow (SBF) were measured simultaneously. O2Hb concentration in PFC and M1 was significantly decreased in initial phase of the exercise, while it was significantly increased from the mid to final phase for both intensities compared with resting state values (p < 0.01). The O2Hb concentrations in the PFC and M1 were significantly decreased in the initial exercise phase. However, the MAP and SBF values did not exhibit a similar pattern. The main findings of our study were the follows: (1) During cycle ergometer exercise at the 30% and 50% O2Hb peak, the after O2Hb concentrations were transiently decreased in the initial exercise phase, and the concentrations then steadily increased in both the PFC and M1; and (2) the duration of the transient decreases in the O2Hb concentrations varied according to the brain region and exercise intensity.

  13. Prolonged administration of recombinant human erythropoietin increases submaximal performance more than maximal aerobic capacity

    DEFF Research Database (Denmark)

    Thomsen, J J; Rentsch, R L; Robach, P

    2007-01-01

    The effects of recombinant human erythropoietin (rHuEpo) treatment on aerobic power (VO2max) are well documented, but little is known about the effects of rHuEpo on submaximal exercise performance. The present study investigated the effect on performance (ergometer cycling, 20-30 min at 80......HuEpo treatment VO2max increased (PVO2max) was increased by 54.0 and 54.3% (P... week 11), TTE was decreased by 26.8% as compared to pre rHuEpo administration. In conclusion, in healthy non-athlete subjects rHuEpo administration prolongs submaximal exercise performance by about 54% independently of the approximately 12% increase in VO2max....

  14. Effect of caffeine intake on critical power model parameters determined on a cycle ergometer DOI:10.5007/1980-0037.2010v12n1p49

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Machado

    2010-12-01

    Full Text Available The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg or placebo (maltodextrin 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively. The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p< 0.01. A high association (r2 was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively. We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.

  15. Climatic chamber ergometer

    CSIR Research Space (South Africa)

    Atkins, AR

    1968-01-01

    Full Text Available The design and calibration of an ergometer for exercising subjects during calorimetric studies in the climate chamber, are described. The ergometer is built into the climatic chamber and forms an integral part of the whole instrumentation system foe...

  16. Measuring submaximal performance parameters to monitor fatigue and predict cycling performance: a case study of a world-class cyclo-cross cyclist.

    Science.gov (United States)

    Lamberts, Robert P; Rietjens, Gerard J; Tijdink, Hendrik H; Noakes, Timothy D; Lambert, Michael I

    2010-01-01

    Recently a novel submaximal test, known as the Lamberts and Lambert submaximal cycle test (LSCT), has been developed with the purpose of monitoring and predicting changes in cycling performance. Although this test has been shown to be reliable and able to predict cycling performance, it is not known whether it can measure changes in training status. Therefore, the aim of this study was to determine whether the LSCT is able to track changes in performance parameters, and objective and subjective markers of well-being. A world class cyclo-cross athlete (31 years) volunteered to participate in a 10-week observational study. Before and after the study, a peak power output (PPO) test with respiratory gas analysis (VO(2max)) and a 40-km time trial (40-km TT) test were performed. Training data were recorded in a training logbook with a daily assessment of well-being, while a weekly LSCT was performed. After the training period all performance parameters had improved by a meaningful amount (PPO +5.2%; 40-km TT time -2.5%; VO(2max) +1.4%). Increased training loads during weeks 2 and 6 and the subsequent training-induced fatigue was reflected in the increased well-being scores. Changes during the LSCT were most clearly notable in (1) increased power during the first minute of third stage, (2) increased rating of perceived exertion during second and third stages, and (3) a faster heart rate recovery after the third stage. In conclusion, these data suggest that the LSCT is able to track changes in training status and detect the consequences of sharp increases in training loads which seem to be associated with accumulating fatigue.

  17. OMNI and Borg scales for the prescription of cycle ergometer exercise. DOI: 10.5007/1980-0037.2011v13n2p117

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    André Calil e Silva

    2011-02-01

    Full Text Available The Borg and OMNI scales of perceived exertion have been widely validated for the identification of exercise intensity. The objective of this study was to test the agreement between the categories of the Borg (6-20 and OMNI-Cycle scales for the prescription of cycle ergometer exercise and to propose a new conversion table. Twenty-six male indoor cyclists (17-41 years pedalled for 3 min at six self-selected increasing loads. These loads corresponded to categories 9, 11, 13, 15, 17, and 19 of the Borg scale in one session, and to categories 2, 4, 5, 7, 8, and 10 of the OMNI scale in the other session. At the end of each stage, heart rate (HR and power (W were recorded. Pearson’s correlation coefficient between scales was calculated. Agreement between the categories of the scales was tested by ANOVA for repeated measures, followed by the Tukey test (p < 0.05. The correlation between the two scales was high (r = 0.87, p < 0.05. Significant difference between the two scales was observed for HR in the first three categories. W differed significantly only in the first two categories. The conversion tested showed a significant correlation. However, there were significant differences in HR in the first three categories and in W in the first two. The following agreement is proposed: Borg 11, 13, 15, 17, and 19 corresponding to OMNI 2, 4, 7, 8, and 10.

  18. Early rehabilitation using a passive cycle ergometer on muscle morphology in mechanically ventilated critically ill patients in the Intensive Care Unit (MoVe-ICU study): study protocol for a randomized controlled trial.

    Science.gov (United States)

    dos Santos, Laura Jurema; de Aguiar Lemos, Fernando; Bianchi, Tanara; Sachetti, Amanda; Dall' Acqua, Ana Maria; da Silva Naue, Wagner; Dias, Alexandre Simões; Vieira, Silvia Regina Rios

    2015-08-28

    Patients in Intensive Care Units (ICU) are often exposed to prolonged immobilization which, in turn, plays an important role in neuromuscular complications. Exercise with a cycle ergometer is a treatment option that can be used to improve the rehabilitation of patients on mechanical ventilation (MV) in order to minimize the harmful effects of immobility. A single-blind randomized controlled trial (the MoVe ICU study) will be conducted to evaluate and compare the effects of early rehabilitation using a bedside cycle ergometer with conventional physical therapy on the muscle morphology of the knee extensors and diaphragm in critical ill patients receiving MV. A total of 28 adult patients will be recruited for this study from among those admitted to the intensive care department at the Hospital de Clínicas de Porto Alegre. Eligible patients will be treated with MV from a period of 24 to 48 h, will have spent maximum of 1 week in hospital and will not exhibit any characteristics restricting lower extremity mobility. These subjects will be randomized to receive either conventional physiotherapy or conventional physiotherapy with an additional cycle ergometer intervention. The intervention will be administered passively for 20 min, at 20 revolutions per minute (rpm), once per day, 7 days a week, throughout the time the patients remain on MV. Outcomes will be cross-sectional quadriceps thickness, length of fascicle, pennation angle of fascicles, thickness of vastus lateralis muscle, diaphragm thickness and excursion of critical ICU patients on MV measured with ultrasound. The MoVe-ICU study will be the first randomized controlled trial to test the hypothesis that early rehabilitation with a passive cycle ergometer can preserve the morphology of knee extensors and diaphragm in critical patients on MV in ICUs. NCT02300662 (25 November 2014).

  19. Effect of acute exercise-induced fatigue on maximal rate of heart rate increase during submaximal cycling.

    Science.gov (United States)

    Thomson, Rebecca L; Rogers, Daniel K; Howe, Peter R C; Buckley, Jonathan D

    2016-01-01

    Different mathematical models were used to evaluate if the maximal rate of heart rate (HR) increase (rHRI) was related to reductions in exercise performance resulting from acute fatigue. Fourteen triathletes completed testing before and after a 2-h run. rHRI was assessed during 5 min of 100-W cycling and a sigmoidal (rHRIsig) and exponential (rHRIexp) model were applied. Exercise performance was assessed using a 5-min cycling time-trial. The run elicited reductions in time-trial performance (1.34 ± 0.19 to 1.25 ± 0.18 kJ · kg(-1), P exercise HR (73.0 ± 8.4 to 90.5 ± 11.4 beats · min(-1), P exercise and steady-state HR. rHRIsig was reduced following acute exercise-induced fatigue, and correlated with difference in performance.

  20. Balance in single-limb stance in healthy subjects – reliability of testing procedure and the effect of short-duration sub-maximal cycling

    Directory of Open Access Journals (Sweden)

    Roberts David

    2003-06-01

    Full Text Available Abstract Background To assess balance in single-limb stance, center of pressure movements can be registered by stabilometry with force platforms. This can be used for evaluation of injuries to the lower extremities. It is important to ensure that the assessment tools we use in the clinical setting and in research have minimal measurement error. Previous studies have shown that the ability to maintain standing balance is decreased by fatiguing exercise. There is, however, a need for further studies regarding possible effects of general exercise on balance in single-limb stance. The aims of this study were: 1 to assess the test-retest reliability of balance variables measured in single-limb stance on a force platform, and 2 to study the effect of exercise on balance in single-limb stance, in healthy subjects. Methods Forty-two individuals were examined for test-retest reliability, and 24 individuals were tested before (pre-exercise and after (post-exercise short-duration, sub-maximal cycling. Amplitude and average speed of center of pressure movements were registered in the frontal and sagittal planes. Mean difference between test and retest with 95% confidence interval, the intraclass correlation coefficient, and the Bland and Altman graphs with limits of agreement, were used as statistical methods for assessing test-retest reliability. The paired t-test was used for comparisons between pre- and post-exercise measurements. Results No difference was found between test and retest. The intraclass correlation coefficients ranged from 0.79 to 0.95 in all stabilometric variables except one. The limits of agreement revealed that small changes in an individual's performance cannot be detected. Higher values were found after cycling in three of the eight stabilometric variables. Conclusions The absence of systematic variation and the high ICC values, indicate that the test is reliable for distinguishing among groups of subjects. However, relatively large

  1. VO2@RER1.0: a novel submaximal cardiopulmonary exercise index.

    Science.gov (United States)

    Chin, Clifford; Kazmucha, Jeffrey; Kim, Nancy; Suryani, Reny; Olson, Inger

    2010-01-01

    Maximal oxygen consumption (VO2max) is the "gold standard" by which to assess functional capacity; however, it is effort dependent. VO2@RER1.0 is defined when VO2 = VCO2. Between December 22, 1997 and November 9, 2004, 305 pediatric subjects underwent cycle ergometer cardiopulmonary exercise testing, exercised to exhaustion, and reached a peak respiratory exchange ratio > or = 1.10. Group 1 subjects achieved a peak VO2 > or = 80% of predicted VO2max; group 2 subjects achieved a peak VO2 subjects achieved a peak VO2 between 61 and 79% of predicted VO2max. Linear regression analysis was performed for VO2@RER1.0 as a function of predicted VO2 for group 1 subjects. A -2 SD regression line and equation was created. VO2@RER1.0 data from groups 2 and 3 were plotted onto the normative graph. Contingency table and relative-risk analysis showed that an abnormal VO2@RER1.0 predicted an abnormal peak VO2(positive-predictive value 83%, negative-predictive value 85%, sensitivity 84%, and specificity 84%). VO2@RER1.0 is a highly sensitive, specific, and predictive submaximal index of functional capacity. This submaximal index is easy to identify without subjectivity. This index may aid in the evaluation of subjects who cannot exercise to maximal parameters.

  2. Comparison of cardiovascular responses between upright and recumbent cycle ergometers in healthy young volunteers performing low-intensity exercise: assessment of reliability of the oxygen uptake calculated by using the ACSM metabolic equation.

    Science.gov (United States)

    Saitoh, Masakazu; Matsunaga, Atsuhiko; Kamiya, Kentaro; Ogura, Misao N; Sakamoto, Junko; Yonezawa, Ryusuke; Kasahara, Yusuke; Watanabe, Hiroyuki; Masuda, Takashi

    2005-05-01

    To clarify (1) differences in cardiovascular response during low-intensity exercise in the upright versus the recumbent position, and (2) whether the oxygen uptake (V o 2 ) calculated by the American College of Sports Medicine (ACSM) metabolic equation reflects the actual V o 2 at low-intensity testing. Repeated-measures comparison study. University research laboratory. Thirty-one healthy, young volunteers (age, 23+/-2y). Not applicable. Blood pressure, rate pressure product (RPP), V o 2 , oxygen pulse, carbon dioxide output (V co 2 ), and ventilatory equivalent (V e ) were measured during graded exercise testing using upright and recumbent cycle ergometers. The estimated V o 2 was calculated by using the ACSM metabolic equation. Systolic blood pressure, RPP, V o 2 , oxygen pulse, V co 2 , and V e at 15 or 30W were significantly higher in the recumbent position than in the upright one ( P intensity, from 15 to 70W ( P intensity exercise using a recumbent cycle ergometer. The V o 2 estimated using the ACSM metabolic equation did not reflect the actual V o 2 during low-intensity exercise at 70W or less.

  3. Electromyography during pedaling on upright and recumbent ergometer.

    Science.gov (United States)

    Lopes, Alexandre Dias; Alouche, Sandra Regina; Hakansson, Nils; Cohen, Moisés

    2014-02-01

    Ergometers are used during rehabilitation and fitness to restore range of motion, muscular strength, and cardiovascular fitness. The primary difference between upright and recumbent ergometers is that the seat and crank spindle are aligned nearly vertically on upright bicycles and nearly horizontally on recumbent ergometers. In addition, recumbent ergometers are characterized by large seats with backrests to provide support for the upper body and are low to the ground, permitting easier access for wheelchair users and individuals with mobility impairments. Despite the great utility of the recumbent bike, it has not been studied with regard to energy costs or muscular output. This is the first study to investigate the differences between two commercial ergometers by analyzing of lower limb EMG in participants who are not habitual cyclers. Ten non-cyclist males with no history of musculoskeletal lower limb injury pedaled on standard recumbent and upright ergometers. EMG data were recorded from the volunteers' lower limb muscles (rectus femoris, semitendinosus, tibialis anterior, and medial gastrocnemius muscles). EMG signals were normalized to the highest EMG signals recorded for the maximum voluntary isometric contractions (MVIC). The peak normalized EMG value of the studied muscles over the average of the 10 pedal cycles was analyzed. The differences in average peak muscle activity were not statistically significant for any of the four muscles tested. Pedaling a recumbent ergometer resulted in greater activity in two (semitendinosus and tibialis anterior) of the four muscles studied. Only the rectus femoris muscle demonstrated greater activity during upright pedaling. There were no differences in the EMG activity of the muscles studied during pedaling on a standard recumbent and an upright stationary exercise ergometer at moderate workload. This increased understanding of muscle activity during pedaling may be useful in the development of new exercise protocols and

  4. Computer-controlled wheelchair ergometer

    NARCIS (Netherlands)

    R. Niesing (Ruud); F. Eijskoot (F.); R. Kranse (Ries); A.H. den Ouden (A.); J. Storm (J.); D. Veeger (Dirkjan); L.H. van der Woude (Luc); C.J. Snijders (Chris)

    1990-01-01

    textabstractA new wheelchair ergometer has been designed in which a combination of realistic simulation of wheelchair propulsion-with adjustable parameters for rolling resistance, air drag, wind speed and slope-and force measurement has been realised. The static solution enables the measurement of

  5. Addition of vitamin B12 to exercise training improves cycle ergometer endurance in advanced COPD patients: A randomized and controlled study.

    Science.gov (United States)

    Paulin, Fernanda Viana; Zagatto, Alessandro Moura; Chiappa, Gaspar R; Müller, Paulo de Tarso

    2017-01-01

    Vitamin B12 is essential in the homocysteine, mitochondrial, muscle and hematopoietic metabolisms, and its effects on exercise tolerance and kinetics adjustments of oxygen consumption (V'O2p) in rest-to-exercise transition in COPD patients are unknown. This randomized, double-blind, controlled study aimed to verify a possible interaction between vitamin B12 supplementation and these outcomes. After recruiting 69 patients, 35 subjects with moderate-to-severe COPD were eligible and 32 patients concluded the study, divided into four groups (n = 8 for each group): 1. rehabilitation group; 2. rehabilitation plus B12 group; 3. B12 group; and 4. placebo group. The primary endpoint was cycle ergometry endurance before and after 8 weeks and the secondary endpoints were oxygen uptake kinetics parameters (time constant). The prevalence of vitamin B12 deficiency was high (34.4%) and there was a statistically significant interaction (p  0.05 for both). Supplementation with vitamin B12 appears to lead to discrete positive effects on exercise tolerance in groups of subjects with more advanced COPD and further studies are needed to establish indications for long-term supplementation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Blunted Maximal and Submaximal Responses to Cardiopulmonary Exercise Tests in Patients With Parkinson Disease.

    Science.gov (United States)

    Kanegusuku, Hélcio; Silva-Batista, Carla; Peçanha, Tiago; Nieuwboer, Alice; Silva, Natan D; Costa, Luiz A; de Mello, Marco T; Piemonte, Maria E; Ugrinowitsch, Carlos; Forjaz, Cláudia L

    2016-05-01

    To investigate submaximal and maximal responses during maximal cardiopulmonary exercise tests in subjects with Parkinson disease (PD). Cross-sectional. A PD association. A sample (N=68) of subjects with PD (n=48; mean age, 66±8y; modified Hoehn and Yahr stage between 2 and 3; "on" state of medication) and age-matched controls without PD (n=20; mean age, 64±9y). Maximal cardiopulmonary exercise test on a cycle ergometer. Oxygen uptake (V˙o2), systolic blood pressure (SBP), and heart rate assessed at rest, submaximal intensities (ie, anaerobic threshold [AT] and respiratory compensation point), and maximal intensity (peak exercise). Compared with control subjects, subjects with PD had lower V˙o2, heart rate, and SBP at respiratory compensation point and peak exercise (V˙o2: 14.6±3.6mL⋅kg⋅min vs 17.9±5.5mL⋅kg⋅min and 17.7±4.8mL⋅kg⋅min vs 21.5±6.6mL⋅kg⋅min; heart rate: 119±17beats/min vs 139±12beats/min and 132±20beats/min vs 158±13beats/min; SBP: 151±17mmHg vs 172±20mmHg and 166±21mmHg vs 187±24mmHg; P≤.05). They also had lower heart rate at AT (102±14beats/min vs 110±13beats/min; P≤.05), whereas V˙o2 and SBP at this intensity were similar to those of control subjects. Subjects with PD demonstrated blunted metabolic and cardiovascular responses to submaximal and maximal exercise tests, especially at intensities above AT, which are in line with autonomic disturbances present in patients with PD. Future studies need to determine how this affects performance, participation, and responses of these patients to exercise training at different intensities. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  7. Computer-controlled wheelchair ergometer.

    Science.gov (United States)

    Niesing, R; Eijskoot, F; Kranse, R; den Ouden, A H; Storm, J; Veeger, H E; van der Woude, L H; Snijders, C J

    1990-07-01

    A new wheelchair ergometer has been designed in which a combination of realistic simulation of wheelchair propulsion--with adjustable parameters for rolling resistance, air drag, wind speed and slope--and force measurement has been realised. The static solution enables the measurement of physiological and kinesiological parameters. All data from force transducers in seat and backrest, torque transducers in the wheels and force transducers in the wheelframes as well as the acquired speed are sampled in a data-acquisition system. An offline curve processor allows the acquired data to be processed with standard or custom-programmed routines. Preliminary results have been added and are discussed.

  8. How Hinge Positioning in Cross-Country Ski Bindings Affect Exercise Efficiency, Cycle Characteristics and Muscle Coordination during Submaximal Roller Skiing.

    Directory of Open Access Journals (Sweden)

    Conor M Bolger

    Full Text Available The purposes of the current study were to 1 test if the hinge position in the binding of skating skis has an effect on gross efficiency or cycle characteristics and 2 investigate whether hinge positioning affects synergistic components of the muscle activation in six lower leg muscles. Eleven male skiers performed three 4-min sessions at moderate intensity while cross-country ski-skating and using a klapskate binding. Three different positions were tested for the binding's hinge, ranging from the front of the first distal phalange to the metatarsal-phalangeal joint. Gross efficiency and cycle characteristics were determined, and the electromyographic (EMG signals of six lower limb muscles were collected. EMG signals were wavelet transformed, normalized, joined into a multi-dimensional vector, and submitted to a principle component analysis (PCA. Our results did not reveal any changes to gross efficiency or cycle characteristics when altering the hinge position. However, our EMG analysis found small but significant effects of hinge positioning on muscle coordinative patterns (P < 0.05. The changed patterns in muscle activation are in alignment with previously described mechanisms that explain the effects of hinge positioning in speed-skating klapskates. Finally, the within-subject results of the EMG analysis suggested that in addition to the between-subject effects, further forms of muscle coordination patterns appear to be employed by some, but not all participants.

  9. Physiological responses to ergometer and on-water incremental rowing tests.

    Science.gov (United States)

    Vogler, Andrew J; Rice, Anthony J; Gore, Christopher J

    2010-09-01

    This study evaluated the validity of ergometer tests against the criterion of on-water rowing and determined the reliability of field measurements by comparing results between ergometer (ERG) and on-water (OW) tests. Seven male rowers completed incremental tests on a Concept2 rowing ergometer and in a single scull. Average power output, oxygen consumption (VO2), heart rate (HR), blood lactate concentration (BLa) and distance completed were measured during each ERG and OW workload. DATA TREATMENT: Linear regression between power output and HR, BLa, VO2 and distance allowed submaximal results to be compared between ERG and OW tests at equivalent intensities based on five standard power outputs. Submaximal results were analyzed using repeated measure factorial ANOVAs and maximal data used dependent t tests (P < .05), the magnitude of differences were also classified using effect size analyses. The reliability of repeated measurements was established using Typical Error. Differences between ERG and OW submaximal results were not statistically significant for power output, HR, BLa, and VO2, but distance completed (P < .001) was higher during the ERG test. However, the magnitude of physiological response differences between the ERG and OW tests varied between individuals. Mean HR at anaerobic threshold showed good agreement between both tests (r = .81), but the standard error of the estimate was 9 beats per minute. Individual variation in physiological response differences between ERG and OW tests meant that training intensity recommendations from the ERG test were not applicable to on-water training for some rowers, but provided appropriate prescriptions for most athletes.

  10. The Effect of Concurrent Plyometric Training Versus Submaximal Aerobic Cycling on Rowing Economy, Peak Power, and Performance in Male High School Rowers.

    Science.gov (United States)

    Egan-Shuttler, Julian D; Edmonds, Rohan; Eddy, Cassandra; O'Neill, Veronica; Ives, Stephen J

    2017-12-01

    Plyometric training has been shown to increase muscle power, running economy, and performance in athletes. Despite its use by rowing coaches, it is unknown whether plyometrics might improve rowing economy or performance. The purpose was to determine if plyometric training, in conjunction with training on the water, would lead to improved rowing economy and performance. Eighteen male high school rowers were assigned to perform 4 weeks of either plyometric training (PLYO, n = 9) or steady-state cycling below ventilatory threshold (endurance, E, n = 9), for 30 min prior to practice on the water (matched for training volume) 3 days per week. Rowing performance was assessed through a 500-m rowing time trial (TT) and peak rowing power (RP), while rowing economy (RE) was assessed by measuring the oxygen cost over four work rates (90, 120, 150, and 180 W). Rowing economy was improved in both PLYO and E (p  0.05). Finally, RP was moderately higher in the PLYO group post-training (E 569 ± 75 W, PLYO 629 ± 51 W, ES = 0.66) CONCLUSIONS: In a season when the athletes performed no rowing sprint training, 4 weeks of plyometric training improved the 500-m rowing performance and moderately improved peak power. This increase in performance may have been mediated by moderate improvements in rowing power, but not economy, and warrants further investigation.

  11. Perceived exertion and anaerobic threshold during the menstrual cycle.

    Science.gov (United States)

    Stephenson, L A; Kolka, M A; Wilkerson, J E

    1982-01-01

    Six adult females with normal menstrual cycles (28-31 d in length) volunteered to exercise on a bicycle ergometer on five different days of their menstrual cycles (days 2, 8, 14, 20, and 26; day 1 = onset of menstruation). Each day the subjects exercised at a maximum work load (184.4 W) and at four submaximal exercise intensities (45.0, 83.1, 121.4 and 154.4 W). Ratings of perceived exertion (RPE) were obtained during minute 4 of each 5-min submaximal exercise bout and at exhaustion each day. Overall, RPE was linearly correlated with heart rate (r = 0.87) when all exercise intensities and cycle days were considered. There was no statistically significant (P greater than 0.05) change in RPE at any exercise intensity related to cycle day. Factors (expired ventilatory volume, respiratory frequency, tidal volume, end-tidal CO2 tension, and heart rate) that may have affected RPE, maximal aerobic power, and anaerobic threshold (AT) were also statistically unchanged because of cycle day. Anaerobic threshold averaged 68.7% of the VO2max, or 1.592 l . min for all cycle days, as determined by the total expiratory volume/oxygen uptake "break point" method of Wasserman and co-workers (18). These data support the utilization of female subjects with normal menstrual cycles in psychophysiological studies without regard to menstrual cycle phase.

  12. The effect of short-duration sub-maximal cycling on balance in single-limb stance in patients with anterior cruciate ligament injury: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Roberts David

    2004-11-01

    Full Text Available Abstract Background It has previously been shown that an anterior cruciate ligament (ACL injury may lead to impaired postural control, and that the ability to maintain postural control is decreased by fatigue in healthy subjects. To our knowledge, no studies have reported the effect of fatigue on postural control in subjects with ACL injury. This study was aimed at examining the effect of fatigue on balance in single-limb stance in subjects with ACL injury, and to compare the effects, and the ability to maintain balance, with that of a control group of uninjured subjects. Methods Thirty-six patients with unilateral, non-operated, non-acute ACL injury, and 24 uninjured subjects were examined with stabilometry before (pre-exercise and immediately after (post-exercise short-duration, sub-maximal cycling. In addition, the post-exercise measurements were compared, to evaluate the instantaneous ability to maintain balance and any possible recovery. The amplitude and average speed of center of pressure movements were registered in the frontal and sagittal planes. The paired t-test was used for the intra-group comparisons, and the independent t-test for the inter-group comparisons, with Bonferroni correction for multiple comparisons. Results No differences were found in the effects of exercise between the patients and the controls. Analysis of the post-exercise measurements revealed greater effects or a tendency towards greater effects on the injured leg than in the control group. The average speed was lower among the patients than in the control group. Conclusions The results of the present study showed no differences in the effects of exercise between the patients and the controls. However, the patients seemed to react differently regarding ability to maintain balance in single-limb stance directly after exercise than the control group. The lower average speed among the patients may be an expression of different neuromuscular adaptive strategies than

  13. Influence of fatigue on EMG/force ratio and cocontraction in cycling.

    Science.gov (United States)

    Hautier, C A; Arsac, L M; Deghdegh, K; Souquet, J; Belli, A; Lacour, J R

    2000-04-01

    The purpose of the present study was to observe force and power losses and electromyographic manifestations of fatigue during repeated sprints performed on a friction-loaded cycle ergometer. Ten subjects performed 15 maximal 5-s sprints with 25-s rests between them. Power, velocity, and torque were measured during sprints 1 and 13 and during two submaximal constant-velocity (50 rpm) periods of cycling performed before and after the sprints. The EMG signals of five leg muscles were stored to determine the EMG/force ratio of power producer muscles and the coactivation of antagonist muscles. The power producer muscles were activated to the same level during sprints 1 and 13, despite a loss of force, whereas the vastus lateralis muscle was recruited more during the submaximal cycling period under fatigue conditions. This led to an increased EMG/force ratio for the power producer muscles, indicating the peripheral fatigue status of these muscles. Antagonist muscles were less activated during the sprints after fatigue; whereas they stayed unchanged during the last submaximal cycling period. This suggests that there is a decrease in coactivation as agonist force is lost. This decrease in coactivation under fatigue conditions has not been previously reported and is probably due to the training status of the subjects. Subjects may have learned to better use their antagonist muscles to efficiently transfer force and power to the rotating pedal. This coordination can be adapted to cope with fatigue of the power producer muscles.

  14. The Effects of Caffeine Supplementation on Physiological Responses to Submaximal Exercise in Endurance-Trained Men.

    Science.gov (United States)

    Glaister, Mark; Williams, Benjamin Henley; Muniz-Pumares, Daniel; Balsalobre-Fernández, Carlos; Foley, Paul

    2016-01-01

    The aim of this study was to evaluate the effects of caffeine on physiological responses to submaximal exercise, with a focus on blood lactate concentration ([BLa]). Using a randomised, single-blind, crossover design; 16 endurance-trained, male cyclists (age: 38 ± 8 years; height: 1.80 ± 0.05 m; body mass: 76.6 ± 7.8 kg; [Formula: see text]: 4.3 ± 0.6 L∙min-1) completed four trials on an electromagnetically-braked cycle ergometer. Each trial consisted of a six-stage incremental test (3 minute stages) followed by 30 minutes of passive recovery. One hour before trials 2-4, participants ingested a capsule containing 5 mg∙kg-1 of either caffeine or placebo (maltodextrin). Trials 2 and 3 were designed to evaluate the effects of caffeine on various physiological responses during exercise and recovery. In contrast, Trial 4 was designed to evaluate the effects of caffeine on [BLa] during passive recovery from an end-exercise concentration of 4 mmol∙L-1. Relative to placebo, caffeine increased [BLa] during exercise, independent of exercise intensity (mean difference: 0.33 ± 0.41 mmol∙L-1; 95% likely range: 0.11 to 0.55 mmol∙L-1), but did not affect the time-course of [BLa] during recovery (p = 0.604). Caffeine reduced ratings of perceived exertion (mean difference: 0.5 ± 0.7; 95% likely range: 0.1 to 0.9) and heart rate (mean difference: 3.6 ± 4.2 b∙min-1; 95% likely range: 1.3 to 5.8 b∙min-1) during exercise, with the effect on the latter dissipating as exercise intensity increased. Supplement × exercise intensity interactions were observed for respiratory exchange ratio (p = 0.004) and minute ventilation (p = 0.034). The results of the present study illustrate the clear, though often subtle, effects of caffeine on physiological responses to submaximal exercise. Researchers should be aware of these responses, particularly when evaluating the physiological effects of various experimental interventions.

  15. Effect of music on submaximal cycling

    African Journals Online (AJOL)

    Boutcher SH, Trenske M. The effects of sensory deprivation and music on perceived exertion and affect during exercise. Journal of Sport and Exercise. Psychology 1990; 12: 167-76. 4. Grant S, Aitchison T, Henderson E, et al. A comparison of the reproduc- ibility and the sensitivity to change of visual analogue scales, Borg ...

  16. Cardiovascular responses during a submaximal exercise test in patients with Parkinson's disease.

    Science.gov (United States)

    Speelman, Arlène D; Groothuis, Jan T; van Nimwegen, Marlies; van der Scheer, Ellis S; Borm, George F; Bloem, Bastiaan R; Hopman, Maria T E; Munneke, Marten

    2012-01-01

    Patients with Parkinson's disease (PD) are physically less active than controls, and autonomic dysfunction may contribute to this sedentary lifestyle. Specifically, an altered cardiovascular response to physical effort may restrict physical activities. To assess the cardiovascular responses to a submaximal exercise test in PD patients and controls, 546 sedentary PD patients and 29 sedentary healthy controls performed the Åstrand-Rhyming submaximal cycle exercise test. Average heart rate was used to estimate maximal oxygen consumption (VO2max). Variables that may affect submaximal activity in PD patients, including disease severity, fatigue, and level of physical activity in daily life, were recorded. Fewer PD patients (46%) completed the submaximal exercise test successfully than the controls (86%). The estimated VO2max of patients with a successful test was 34% lower than the controls (p physical activities further.

  17. The effect of Sub-maximal exercise-rehabilitation program on cardio-respiratory endurance indexes and oxygen pulse in patients with spastic cerebral palsy

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    M Izadi

    2006-05-01

    Full Text Available Background: Physical or cardio-respiratory fitness are of the best important physiological variables in children with cerebral palsy (CP, but the researches on exercise response of individuals with CP are limited. Our aim was to determine the effect of sub-maximal rehabilitation program (aerobic exercise on maximal oxygen uptake, oxygen pulse and cardio- respiratory physiological variables of children with moderate to severe spastic cerebral palsy diplegia and compare with able-bodied children. Methods: In a controlled clinical trial study, 15 children with diplegia spastic cerebral palsy, were recruited on a voluntarily basis (experimental group and 18 subjects without neurological impairments selected as control group. In CP group, aerobic exercise program performed on the average of exercise intensity (144 beat per minute of heart rate, 3 times a week for 3 months. The time of each exercise session was 20-25 minutes. Dependent variables were measured in before (pretest and after (post test of rehabilitation program through Mac Master Protocol on Tantories cycle ergometer in CP group and compared with the control group. Results: The oxygen pulse (VO2/HR during ergometery protocol was significantly lower in CP group than normal group (P<0.05. No significant statistical difference in maximal oxygen uptake (VO2 max was found between groups. The rehabilitation program leads to little increase of this variable in CP group. After sub-maximal exercise in pretest and post test, the heart rate of patient group was greater than control group, and aerobic exercise leads to significant decrease in heart rate in CP patients(P<0.05. Conclusion: The patients with spastic cerebral palsy, because of high muscle tone, severe spasticity and involuntarily movements have higher energy cost and lower aerobic fitness than normal people. The rehabilitation exercise program can improve physiological function of muscle and cardio-respiratory endurance in these

  18. Validated Predictions of Metabolic Energy Consumption for Submaximal Effort Movement.

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    George A Tsianos

    2016-06-01

    Full Text Available Physical performance emerges from complex interactions among many physiological systems that are largely driven by the metabolic energy demanded. Quantifying metabolic demand is an essential step for revealing the many mechanisms of physical performance decrement, but accurate predictive models do not exist. The goal of this study was to investigate if a recently developed model of muscle energetics and force could be extended to reproduce the kinematics, kinetics, and metabolic demand of submaximal effort movement. Upright dynamic knee extension against various levels of ergometer load was simulated. Task energetics were estimated by combining the model of muscle contraction with validated models of lower limb musculotendon paths and segment dynamics. A genetic algorithm was used to compute the muscle excitations that reproduced the movement with the lowest energetic cost, which was determined to be an appropriate criterion for this task. Model predictions of oxygen uptake rate (VO2 were well within experimental variability for the range over which the model parameters were confidently known. The model's accurate estimates of metabolic demand make it useful for assessing the likelihood and severity of physical performance decrement for a given task as well as investigating underlying physiologic mechanisms.

  19. Comparação entre a utilização de saliva e sangue para determinação do lactato mínimo em cicloergômetro e ergômetro de braço em mesa-tenistas Comparacion entre la utilizacion de saliva y sangre para la determinacion del lactato mínimo en cicloergómetro y ergómetro de brazo en tenistas de mesa Comparison between the use of saliva and blood for the minimum lactate determination in arm ergometer and cycle ergometer in table tennis players

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    Alessandro Moura Zagatto

    2004-12-01

    al test de correlación de Pearson con niveles de significancia de 5%. Los LACmin determinados con muestras de sangre y de saliva tanto para el ergômetro de brazo (LACmin brazo 91,71 ± 12,43; Na+min brazo-saliva 71,99 ± 23,42; K+min brazo-saliva 79,67 ± 17,72, como para el cicloergómetro (LACmin ciclo 157,68 ± 13,48; LACmin ciclo-saliva 135,49 ± 33,2; Na+min ciclo-saliva 121,81 ± 51,31; K+min ciclo-saliva 135,49 ± 33,21 no fueron diferentes significativamente. Con todo, estas intensidades no presentaron correlaciones significativas. Se puede entónces concluir que la utilización de los metabólitos en la saliva para la determinación de la del TLM no parece ser posible para este protocolo cuando los ergómetros utilizados son el ergómetro de brazo isocinético y el cicloergómetro.The aim of this study was to verify if it is possible to determine the lactate minimum test (LMT by saliva sodium (Na+, potassium (K+ and lactate (LAC concentrations in arm ergometer and cycle ergometers. Eight male international-level table tennis players participated in this study. To induce increases of lactate concentration in both ergometers, 30 seconds maximal tests were used with maximal force application in constant 102 rpm in isokinetic arm ergometer (Cybex UBE 2432, and loads of 7.5% of body weight (Kp in cycle ergometer (mechanical Monark. After the anaerobic stimulus in arm ergometer, the incremental test was applied at constant 60 rpm, started at 49 watts and increment loads of 16 watts each three minutes. The LMT intensity was determined with the analysis of the blood lactate (LACmin arm and the saliva concentrations of sodium (Na+min arm-saliva and potassium (K+min arm-saliva. For the cycle ergometer, the incremental test started with an intensity of 85 watts and increments of 17 watts at constant speed of 70 rpm. The stages were also of three minutes. The LACmin was determined using blood and saliva samples (LACmin cycle; Na+min cycle-saliva, K+min cycle

  20. Indirect methods of estimating maximal oxygen uptake on the rowing ergometer

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    A Klusiewicz

    2003-09-01

    Full Text Available The aim of the present study was to develop an indirect method of estimating maximal oxygen uptake in oarsmen and oarswomen on the rowing ergometer based on both the submaximal exercises and the commonly used in this sport maximal exercise-type test that simulates rowing the distance of 2000 m. Forty-four oarsmen and 27 oarswomen from both the national team and the direct back-up were enrolled in the investigations. Two exercise tests on the Concept II rowing ergometer were employed: the submaximal test with incremental power output (anaerobic threshold test and the maximal test, simulating rowing the distance of 2000 m in the shortest possible time (2-km test. During both tests, oxygen uptake and heart rate were recorded and the highest values of these parameters registered during the 2-km test were regarded as the VO2max and HRmax indices, respectively. The linear relation of the oxygen uptake to the power output (W on the ergometer was detected in both the male (VO2=1.1328+0.0113W and female (VO2=0.6652+0.0128W athletes. Comparison of the regression lines demonstrated statistically significant differences between the oarsmen and oarswomen with respect to the intercept and the slope of the lines. Mean values of the directly measured VO2max equaled to 5.48±0.59 and 3.68±0.31 l•min-1 in the groups of oarsmen and oarswomen, respectively. The most accurate predicted values of VO2max were obtained based on the linear regression of VO2max against the mean power output (WM in the 2-km test using the following formulas: VO2max (l•min-1 in the males = 1.682+0.0097 WM; VO2max (l•min-1 in the females = 1.631+0.0088 WM. In the males, the difference between the measured and predicted VO2max (∆%, correlation coefficient (r, standard estimation error (SEE, and total error (TE% equaled to 0.12±4.96 (NS, 0.889 (P<0.001, 0.274, and 4.9, respectively. In the females, these values equaled to 0.43±5.02 (NS, 0.801 (P<0.001, 0.19 and 4.95, respectively

  1. Effect of Kayak Ergometer Elastic Tension on Upper Limb EMG Activity and 3D Kinematics.

    Science.gov (United States)

    Fleming, Neil; Donne, Bernard; Fletcher, David

    2012-01-01

    Despite the prevalence of shoulder injury in kayakers, limited published research examining associated upper limb kinematics and recruitment patterns exists. Altered muscle recruitment patterns on-ergometer vs. on-water kayaking were recently reported, however, mechanisms underlying changes remain to be elucidated. The current study assessed the effect of ergometer recoil tension on upper limb recruitment and kinematics during the kayak stroke. Male kayakers (n = 10) performed 4 by 1 min on-ergometer exercise bouts at 85%VO2max at varying elastic recoil tension; EMG, stroke force and three-dimensional 3D kinematic data were recorded. While stationary recoil forces significantly increased across investigated tensions (125% increase, p kayakers maintained normal upper limb kinematics via additional AD recruitment despite ergometer induced recoil forces. Key pointsKayak ergometer elastic tension significantly alters Anterior Deltoid recruitment patterns.Kayakers maintain optimal arm kinematics despite changing external forces via altered shoulder muscle recruitment.Overhead arm movements account for a high proportion of the kayak stroke cycle.

  2. Cardiac autonomic dysfunction in chronic stroke women is attenuated after submaximal exercise test, as evaluated by linear and nonlinear analysis.

    Science.gov (United States)

    Francica, Juliana Valente; Bigongiari, Aline; Mochizuki, Luís; Scapini, Kátia Bilhar; Moraes, Oscar Albuquerque; Mostarda, Cristiano; Caperuto, Erico Chagas; Irigoyen, Maria Cláudia; De Angelis, Katia; Rodrigues, Bruno

    2015-09-29

    We evaluated cardiac autonomic modulation in women with chronic ischemic stroke (at least 4 years post-stroke) at rest and in response to submaximal exercise test. Fourteen post-stroke women (S group) and 10 healthy women (C group) participated in this study. Autonomic modulation (using linear and nonlinear analysis), blood pressure and metabolic variables at rest were evaluated immediately after the exercise test and during the recovery period (20 min). All participants underwent submaximal exercise test on cycle ergometer with gas analysis. At rest, the S group displayed higher lactate concentration, systolic (SBP) and diastolic blood pressure (DBP) values when compared to C group. Furthermore, the S group had lower heart rate variability (HRV) in time domain (SDNN: S = 30 ± 5 vs. 40 ± 8 ms; rMSSD: S = 14 ± 2 vs. C = 34 ± 3 ms), decreased high frequency band of pulse interval (S = 8.4 ± 2 vs. 33.1 ± 9 %) and 2V pattern of symbolic analysis (S = 17.3 ± 1 vs. 30 ± 3 %) (both indicators of cardiac vagal modulation) when compared to C group. Immediately after exercise, S group presented higher values of lactate, SBP, DBP and double product when compared to C group, as well as decreased heart rate recovery (HRR) measured at the first, second and third minutes. At recovery time, all HRV parameters in time and frequency domains improved in the S group; however, HF band remained lower when compared to C group. After the exercise test, women with chronic stroke presented reduced heart rate variability, reduced cardiac vagal modulation, as well as reduced HRR, while displayed an improvement of heart rate variability and cardiac vagal modulation when compared to their baseline. These results reinforce the importance of a physically active lifestyle for cardiovascular autonomic disorders observed in chronic stroke women.

  3. Assessment of aerobic capacity through blood and ventilatory responses in four different ergometers

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    Alessandro Moura Zagatto

    2013-04-01

    Full Text Available The objective of the study was to compare intensities of respiratory compensation point (RCP,anaerobic threshold at onset blood lactate accumulation (OBLA3,5, and anaerobic threshold at lactate abrupt increase (AnTLAC determined in four different ergometers. Hence, eleven table tennis players (19±1 years performed graded exercise tests on cycle ergometer, arm cranking ergometer, treadmill and specific table tennis test. The respiratory response and lactatemia were measured during the tests. We did not find significant diferences among RCP, AnTLAC and OBLA3,5 in arm cranking ergometer (63.4±4.8W, 66.9±4.5W and 64.5±6.1W, respectively, treadmill (11.4±0.4 km.h-1, 11.3±0.3 km.h-1 and 11.1±0.3 km.h-1, respectively, and specific table tennis test (40.5±1.8 bolas.min-1, 42.6±3.6bolas.min-1 and 42.8±5.6bolas.min-1,respectively. However, the OBLA 3,5 (131.9±6.6W was significantly lower than RCP (149.3±4.9W and AnTLAC (149.3±4.7W in the cycle ergometer. Strong and significant correlation coefficients were found in the specific test for all methods (r range 0.83 to 0.95, in arm cranking ergometer between RCP and OBLA 3,5 (r=0.78, and on treadmill running between OBLA3,5 and AnTLAC (r=0.76.Therefore, we conclude that RCP, OBLA3,5 and AnTLAC seem to correspond to the same physiological phenomenon, mostly during specific table tennis test.

  4. A BIOMECHANICAL ASSESSMENT OF ERGOMETER TASK SPECIFICITY IN ELITE FLATWATER KAYAKERS

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    Neil Fleming

    2012-03-01

    Full Text Available The current study compared EMG, stroke force and 2D kinematics during on-ergometer and on-water kayaking. Male elite flatwater kayakers (n = 10 performed matched exercise protocols consisting of 3 min bouts at heart and stroke rates equivalent to 85% of VO2peak (assessed by prior graded incremental test. EMG data were recorded from Anterior Deltoid (AD, Triceps Brachii (TB, Latissimus Dorsi (LD and Vastus Lateralis (VL via wireless telemetry. Video data recorded at 50 Hz with audio triggers pre- and post-exercise facilitated synchronisation of EMG and kinematic variables. Force data were recorded via strain gauge arrays on paddle and ergometer shafts. EMG data were root mean squared (20ms window, temporally and amplitude normalised, and averaged over 10 consecutive cycles. In addition, overall muscle activity was quantified via iEMG and discrete stroke force and kinematic variables computed. Significantly greater TB and LD mean iEMG activity were recorded on-water (239 ± 15 vs. 179 ± 10 µV. s, p < 0.01 and 158 ± 12 vs. 137 ± 14 µV.s, p < 0.05, respectively, while significantly greater AD activity was recorded on-ergometer (494 ± 66 vs. 340 ± 35 µV.s, p < 0.01. Time to vertical shaft position occurred significantly earlier on-ergometer (p < 0.05. Analysis of stroke force data and EMG revealed that increased AD activity was concurrent with increased external forces applied to the paddle shaft at discrete phases of the on-ergometer stroke cycle. These external forces were associated with the ergometer loading mechanism and were not observed on- water. The current results contradict a previous published hypothesis on shoulder muscle recruitment during on-water kayaking.

  5. Met-enkephalin, beta-endorphin and cortisol responses to sub-maximal exercise after sleep disturbances.

    Science.gov (United States)

    Mougin, F; Simon-Rigaud, M L; Mougin, C; Bourdin, H; Jacquier, M C; Henriet, M T; Davenne, D; Kantelip, J P; Magnin, P; Gaillard, R C

    1992-01-01

    The present study compared the effects of partial sleep deprivation and the effects of an intake of a hypnotic compound (zolpidem) prior to bedtime, on sleep and on hormonal and metabolic adaptations to subsequent exercise. Sleep deprivation consisted of a delayed bedtime and an early getting-up time. Eight young subjects, who slept well and were highly trained athletes, were enrolled in this study. Sleep was recorded polygraphically and the following afternoon exercise was performed on a cycle ergometer for 30 min at 75% of maximal oxygen consumption (VO2max) after a 10-min warm up. Met-enkephalin, beta-endorphin, cortisol, and lactate concentrations were measured at rest and during exercise. The data obtained after experimental sleep, with and without medication were compared with those obtained in the reference condition with normal sleep. Both types of sleep reduction decreased the total sleep time, stage 2 sleep, and rapid eye movement sleep, whereas zolpidem administration did not modify either the duration of sleep or the sleep stages. After the reference night, plasma met-enkephalin did not show any significant change at the end of the submaximal exercise, whereas beta-endorphin, cortisol, and lactic acid concentrations increased significantly in all subjects. The changes in concentration in beta-endorphin were significantly related to the changes in cortisol (r = 0.78; P less than 0.01) and to the changes in plasma lactic acid (r = 0.58; P less than 0.05). Cortisol concentrations were also related to lactic acid values (r = 0.94; P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Caracterização do uso do cicloergômetro para auxiliar no atendimento fisioterapêutico em pacientes críticos Characterization of the use of a cycle ergometer to assist in the physical therapy treatment of critically ill patients

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    Ruy Camargo Pires-Neto

    2013-03-01

    Full Text Available OBJETIVO: Analisar as alterações cardiorrespiratórias de pacientes durante o exercício ativo com um cicloergômetro e verificar a aceitação dos pacientes para realizar esse tipo de atividade. MÉTODOS: Foi realizada uma única intervenção de exercício ativo de membros inferiores no cicloergômetro (sem carga durante 5 minutos. As variáveis frequência cardíaca, pressão arterial, frequência respiratória, saturação periférica de oxigênio e escala de dispneia de Borg foram avaliadas em três momentos: antes, durante e imediatamente após o exercício. Ao final, o paciente respondia um questionário avaliando sua satisfação em relação a esse tipo de atividade. RESULTADOS: Participaram do estudo 38 pacientes (65% masculino com 48±16 anos e SOFA=2 (0-5. Durante o exercício, 55% estavam em ar ambiente e 16% utilizaram algum tipo de suporte ventilatório. Comparando-se os valores iniciais e finais das variáveis analisadas, verificou-se um aumento apenas nas variáveis frequência cardíaca (92±17 e 95±18; pOBJECTIVE: The objective of this study was to use a cycle ergometer to assess cardiorespiratory changes during active exercise and to verify patients' satisfaction with this type of activity. METHODS: A single intervention involving active lower limb exercise was performed with a cycle ergometer (without load for 5 minutes. The following variables were measured before, during and immediately after exercise: heart rate, blood pressure, respiratory rate, peripheral oxygen saturation and the Borg dyspnea scale score. Following the exercise, the patients answered a questionnaire to evaluate their satisfaction with this type of activity. RESULTS: A total of 38 patients (65% male with a mean age of 48 ± 16 years old participated in the study. Enrolled patients presented a sequential organ failure assessment (SOFA score of 2 (0 - 5 scale. During the exercise, 16% of the patients used ventilation support and 55% of them were

  7. Substrate utilization during submaximal exercise in children with a severely obese parent

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    Eaves Audrey D

    2012-05-01

    Full Text Available Abstract Background We have reported a reduction in fatty acid oxidation (FAO at the whole-body level and in skeletal muscle in severely obese (BMI ≥ 40 kg/m2 individuals; this defect is retained in cell culture suggesting an inherent component. The purpose of the current study was to determine if an impairment in whole-body fatty acid oxidation (FAO was also evident in children with a severely obese parent. Methods Substrate utilization during submaximal exercise (cycle ergometer was determined in children ages 8–12 y with a severely obese parent (OP, n = 13 or two lean/non-obese (BMI range of 18 to 28 kg/m2 parents (LP, n = 13. A subgroup of subjects (n = 3/group performed 4 weeks of exercise training with substrate utilization measured after the intervention. Results The children did not differ in age (LP vs. OP, respectively (10.7 ± 0.5 vs. 10.2 ± 0.5 y, BMI percentile (65.3 ± 5.2 vs. 75.9 ± 7, Tanner Stage (1.4 ± 0.2 vs. 1.5 ± 0.2, VO2peak (40.3 ± 2.7 vs. 35.6 ± 2.6 ml/kg/min or physical activity levels (accelerometer. At the same absolute workload of 15 W (~38% VO2peak, RER was significantly (P ≤ 0.05 lower in LP vs. OP (0.83 ± 0.02 vs. 0.87 ± 0.01 which was reflected in a reduced reliance on FAO for energy production in the OP group (58.6 ± 5.1 vs. 43.1 ± 4.0% of energy needs during exercise from FAO. At a higher exercise intensity (~65% VO2peak there were no differences in substrate utilization between LP and OP. After exercise training RER tended to decrease (P = 0.06 at the 15 W workload, suggesting an increased reliance on FAO regardless of group. Conclusions These findings suggest that the decrement in FAO with severe obesity has an inherent component that may be overcome with exercise training.

  8. Analysing visual pattern of skin temperature during submaximal and maximal exercises

    Science.gov (United States)

    Balci, Gorkem Aybars; Basaran, Tahsin; Colakoglu, Muzaffer

    2016-01-01

    Aims of this study were to examine our hypotheses assuming that (a) skin temperature patterns would differ between submaximal exercise (SE) and graded maximal exercise test (GXT) and (b) thermal kinetics of Tskin occurring in SE and GXT might be similar in a homogenous cohort. Core temperature (Tcore) also observed in order to evaluate thermoregulatory responses to SE and GXT. Eleven moderately to well-trained male athletes were volunteered for the study (age: 22.2 ± 3.7 years; body mass: 73.8 ± 6.9 kg; height: 181 ± 6.3 cm; body surface area 1.93 ± 0.1 m2; body fat: 12.6% ± 4.2%; V ˙ O2max: 54 ± 9.9 mL min-1 kg-1). Under stabilized environmental conditions in climatic chamber, GXT to volitional exhaustion and 20-min SE at 60% of VO2max were performed on cycle ergometer. Thermal analyses were conducted in 2-min intervals throughout exercise tests. Tskin was monitored by a thermal camera, while Tcore was recorded via an ingestible telemetric temperature sensor. Thermal kinetic analyses showed that Tskin gradually decreased till the 7.58 ± 1.03th minutes, and then initiated to increase till the end of SE (Rsqr = 0.97), while Tskin gradually decreased throughout the GXT (Rsqr = 0.89). Decrease in the level of Tskin during the GXT was significantly below from the SE [F (4, 40) = 2.67, p = 0.07, ηp2 = 0.211]. In the meantime, Tcore continuously increased throughout the SE and GXT (p 0.05). However, total heat energies were calculated as 261.5 kJ/m2 and 416 kJ/m2 for GXT and SE, respectively (p exercises as expected. Tskin curves patterns found to be associated amongst participants at both GXT and SE. Therefore, Tskin kinetics may ensure an important data for monitoring thermoregulation in exercise.

  9. Efeito de oito semanas de suplementação com creatina monoidratada sobre o trabalho total relativo em esforços intermitentes máximos no cicloergômetro de homens treinados Effect of eight weeks of creatine supplementation on relative total work in intermittent maximal efforts in the cycle ergometer of trained men

    Directory of Open Access Journals (Sweden)

    Leandro Ricardo Altimari

    2006-06-01

    Full Text Available Este estudo investigou o efeito de um longo período de suplementação com creatina monoidratada (Cr m sobre o trabalho total relativo (TTR em esforços intermitentes máximos no cicloergômetro de homens treinados. Vinte seis indivíduos foram divididos aleatoriamente em grupo creatina (CR, n=13 e grupo placebo (PL, n=13. Os sujeitos receberam em sistema duplo-cego, doses de Cr m ou placebo-maltodextrina (20 g.d-1 por 5 dias e 3 g.d-1 durante 51 dias subseqüentes. Os grupos tiveram seus hábitos alimentares e sua condição física previamente controlados. Para determinação do TTR os sujeitos foram submetidos a protocolo de exercício em cicloergômetro composto de três Testes de Wingate de 30s separados por dois minutos recuperação, antes e após o período de suplementação. ANOVA, seguido pelo teste post hoc de Tukey, quando pThis study investigated the effect of long-term supplementation with creatine monohydrate (Cr m on relative total work (RTW in intermittent maximal efforts in the cycle ergometer of trained men. Twenty six individuals were randomly divided in creatine group (CR, n=13 and placebo group (PL, n=13. The subjects received in a double-blind manner, doses of Cr m or placebo-maltodextrin (20 g.d-1 for 5 days and 3 g.d-1 for 51 subsequent days. The groups had their alimentary habits and physical fitness controlled previously. For determination of the RTW the subjects were submitted to exercise protocol in cycle ergometer comprised three 30s Anaerobic Wingate Test interspersed with two minutes recovery, before and after the supplementation period. ANOVA, followed by the Tukey post hoc test, when p<0.05, were used for data treatment. There was a significant time effect for RTW (F1,24=8.00; p<0.05, with the CR group demonstrating significant greater (3% on the RTW production compared to PL group after the supplementation period (690.54 ± 46.83 vs 655.71 ± 74.34 J.kg-1 respectively; p<0.05. The results of the present study

  10. EFFECT OF KAYAK ERGOMETER ELASTIC TENSION ON UPPER LIMB EMG ACTIVITY AND 3D KINEMATICS

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    Neil Fleming

    2012-09-01

    Full Text Available Despite the prevalence of shoulder injury in kayakers, limited published research examining associated upper limb kinematics and recruitment patterns exists. Altered muscle recruitment patterns on-ergometer vs. on-water kayaking were recently reported, however, mechanisms underlying changes remain to be elucidated. The current study assessed the effect of ergometer recoil tension on upper limb recruitment and kinematics during the kayak stroke. Male kayakers (n = 10 performed 4 by 1 min on-ergometer exercise bouts at 85%VO2max at varying elastic recoil tension; EMG, stroke force and three-dimensional 3D kinematic data were recorded. While stationary recoil forces significantly increased across investigated tensions (125% increase, p < 0.001, no significant differences were detected in assessed force variables during the stroke cycle. In contrast, increasing tension induced significantly higher Anterior Deltoid (AD activity in the latter stages (70 to 90% of the cycle (p < 0.05. No significant differences were observed across tension levels for Triceps Brachii or Latissimus Dorsi. Kinematic analysis revealed that overhead arm movements accounted for 39 ± 16% of the cycle. Elbow angle at stroke cycle onset was 144 ± 10°; maximal elbow angle (151 ± 7° occurred at 78 ± 10% into the cycle. All kinematic markers moved to a more anterior position as tension increased. No significant change in wrist marker elevation was observed, while elbow and shoulder marker elevations significantly increased across tension levels (p < 0.05. In conclusion, data suggested that kayakers maintained normal upper limb kinematics via additional AD recruitment despite ergometer induced recoil forces

  11. The effect of submaximal exercise on fibrinolysis.

    Science.gov (United States)

    Fras, Zlatko; Keber, Dusan; Chandler, Wayne L

    2004-04-01

    We studied the relationship between sustained submaximal exercise, increased tissue plasminogen activator (t-PA) levels and decreased hepatic clearance of t-PA. Six healthy male volunteers exercised for 35 min while receiving constant rate infusions of either saline or two different doses of recombinant t-PA for 90 min (40 min before, 35 min during and 15 min after exercise). Liver blood flow was estimated simultaneously by constant rate indocyanine green infusion. Since t-PA is cleared rapidly by the liver in direct proportion to liver blood flow, it was expected that a significant decrease in liver blood flow during sustained submaximal exercise would be associated with a proportional increase in plasma t-PA. During submaximal exercise with a saline (placebo) infusion, steady-state t-PA antigen increased from a resting baseline of 6.3 +/- 3.1 to 15.1 +/- 5.1 ng/ml; with a 20 microg/min t-PA infusion, t-PA antigen increased from 33 +/- 12 to 84 +/- 25 ng/ml during exercise; and with a 40 microg/min t-PA infusion, t-PA antigen increased from 77 +/- 38 to 166 +/- 42 ng/ml during exercise. During submaximal exercise, liver blood flow fell on average 71, 68 and 70%, respectively, during the three procedures, while calculated t-PA clearance decreased on average 59, 59 and 53%. t-PA concentration versus time curves, displayed in proportional units, were similar. The comparable relative increases in endogenous and exogenous t-PA with simultaneous proportional decreases in liver blood flow suggests that diminished hepatic t-PA clearance is the major cause of increased t-PA concentration and blood fibrinolytic activity enhancement during sustained submaximal exercise.

  12. Impact of menstrual cycle phase on the exercise status of young, sedentary women.

    Science.gov (United States)

    Redman, Leanne M; Scroop, Garry C; Norman, Robert J

    2003-11-01

    The purpose of the present study was to compare exercise status during the follicular (FP) and luteal (LP) phases of the menstrual cycle of a single group of young, sedentary women, where the marked differential in the blood concentrations of 17beta-oestradiol ([E(2)]) and progesterone ([P(4)]) has the potential to alter the metabolic response to exercise. Fourteen females [21.8 (4.0) years, peak oxygen uptake ( VO(2peak)) cycle ergometer exercise while measurements were made of several metabolic and hormonal variables. With the incremental exercise test, time to exhaustion, maximal power output and total work done were not different between the two phases, nor were the absolute values for VO(2peak) or the corresponding values for ventilation ( VE), respiratory frequency ( f(R)) and heart rate (HR). Resting, end-exercise and peak (post-exercise) plasma lactate concentrations and the lactate threshold were not different between the two phases either. However, as the workloads increased during the incremental protocol, plasma lactate concentration, carbon dioxide output ( VCO(2)) and the respiratory exchange ratio (RER) all were lower during LP, while oxygen uptake ( VO(2)) was higher. With steady-state submaximal exercise, at workloads corresponding to 25% and 75% of menstrual cycle phase-specific VO(2peak), VO(2) and the oxygen pulse ( VO(2)/HR) were higher and RER and plasma lactate concentration lower during LP. Regardless of phase, [E(2)] increased with both incremental and steady-state submaximal exercise, while [P(4)] was unchanged. It is concluded that while exercise capacity, as defined by VO(2peak) and the lactate threshold, is unaffected by cycle phase in young, sedentary women, the metabolic responses in the LP during both incremental and steady-state submaximal exercise suggest a greater dependence on fat as an energy source.

  13. Effect of BMI on Knee Joint Torques in Ergometer Rowing

    NARCIS (Netherlands)

    Roemer, Karen; Hortobagyi, Tibor; Richter, Chris; Munoz-Maldonado, Yolanda; Hamilton, Stephanie

    2013-01-01

    Although an authoritative panel recommended the use of ergometer rowing as a non-weight-bearing form of exercise for obese adults, the biomechanical characterization of ergometer rowing is strikingly absent. We examined the interaction between body mass index (BMI) relative to the lower extremity

  14. Accuracy and Validity of Commercially Available Kayak Ergometers.

    Science.gov (United States)

    Borges, Thiago Oliveira; Bullock, Nicola; Aitken, David; Coutts, Aaron J

    2017-10-01

    This study compared 3 commercially available ergometers for within- and between-brands difference to a first-principle calibration rig. All ergometers underestimated true mean power, with errors of 27.6% ± 3.7%, 4.5% ± 3.5%, and 22.5% ± 1.9% for the KayakPro, WEBA, and Dansprint, respectively. Within-brand ergometer power differences ranged from 17 ± 9 to 22 ± 11 W for the KayakPro, 3 ± 4 to 4 ± 4 W for the WEBA, and 5 ± 3 to 5 ± 4 W for the Dansprint. The linear-regression analysis showed that most kayak ergometers have a stable coefficient of variation (0.9-1.7%) with a moderate effect size. Taken collectively, these findings show that different ergometers present inconsistent outcomes. Therefore, we suggest that athlete testing be conducted on the same ergometer brand, preferably the same ergometer. Optimally, that ergometer should be calibrated using a first-principle device before any athlete testing block.

  15. The oxidant-antioxidant equilibrium, activities of selected lysosomal enzymes and activity of acute phase protein in peripheral blood of 18-year-old football players after aerobic cycle ergometer test combined with ice-water immersion or recovery at room temperature.

    Science.gov (United States)

    Sutkowy, Paweł; Woźniak, Alina; Boraczyński, Tomasz; Boraczyński, Michał; Mila-Kierzenkowska, Celestyna

    2017-02-01

    The goal of the study was to evaluate the effect of an aerobic exercise bout followed by ice-water immersion or recovery at room temperature on the redox state, activities of selected lysosomal enzymes and activity of α1-antitrypsin (AAT) in the blood of healthy sportsmen. Eleven amateur football players aged 18 were randomly assigned to two similar 30-min aerobic cycle ergometer tests followed by a recovery at room temperature (20 °C; Experiment 1) or ice-water immersion (3 °C, 5 min; Experiment 2). Peripheral blood was collected three times during both study experiments: before (baseline), as well as 20 and 40 min after the recovery or immersion. The concentrations of thiobarbituric acid reactive substances in blood plasma (plTBARS) and erythrocytes (erTBARS) were measured. The erythrocytic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were also determined. In the blood serum, the activities of acid phosphatase (AcP), arylsulphatase (ASA), cathepsin D (CTS D) and AAT were evaluated. The activities of AcP, ASA, CTS D and AAT changed similarly during both experiments. The GPx activity decreased 40 min after the exercise/recovery compared to the baseline activity and was lower than 40 min after the exercise/immersion. The exercise followed by the recovery or immersion had no significant effect on the serum lysosomal and AAT activities in the studied men. The exercise/recovery reduced the hydrogen peroxide concentration in the men's erythrocytes, however the exercise/immersion demonstrated the opposite effect. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. A comparison of electromyography and stroke kinematics during ergometer and on-water rowing.

    Science.gov (United States)

    Fleming, Neil; Donne, Bernard; Mahony, Nicholas

    2014-01-01

    This study assessed muscle recruitment patterns and stroke kinematics during ergometer and on-water rowing to validate the accuracy of rowing ergometry. Male rowers (n = 10; age 21 ± 2 years, height 1.90 ± 0.05 m and body mass 83.3 ± 4.8 kg) performed 3 × 3 min exercise bouts, at heart and stroke rates equivalent to 75, 85 and 95% VO2peak, on both dynamic and stationary rowing ergometers, and on water. During exercise, synchronised data for surface electromyography (EMG) and 2D kinematics were recorded. Overall muscle activity was quantified by the integration of rmsEMG and averaged for each 10% interval of the stroke cycle. Muscle activity significantly increased in rectus femoris (RF) and vastus medialis (VM) (P rowing at discrete 10% intervals of stroke cycle. In addition, the drive/recovery ratio was significantly lower during dynamic ergometry compared to on-water (40 ± 1 vs. 44 ± 1% at 95%, P rowing. These differences may be due to altered acceleration and deceleration of moving masses on-ergometer not perfectly simulating the on-water scenario.

  17. Influence of Ergometer Design on Physiological Responses during Rowing.

    Science.gov (United States)

    Rossi, J; Piponnier, E; Vincent, L; Samozino, P; Messonnier, L

    2015-11-01

    The aim of this study was to compare the physiological responses and rowing efficiency on 2 different rowing ergometers: stationary vs. dynamic ergometers manufactured by Concept2. 11 oarswomen and oarsmen rowed 4 min at 60% and 70% of peak power output on both ergometers (randomized order). Power output, stroke rate, heart rate, oxygen uptake, carbon dioxide production, lactate accumulation and rating of perceived exertion were recorded at each stage on the 2 ergometers. Gross and net efficiencies were computed. Exercise intensity was associated with increases in all parameters. Rowing on dynamic ergometer was associated with higher heart rate, oxygen uptake, carbon dioxide production and stroke rate, concomitantly to lower blood lactate accumulation but also to lower gross and net efficiencies. The present study showed that rowing efficiency and blood lactate accumulation were lower on the Concept2 dynamic ergometer than on its stationary counterpart. If the use of the Concept2 dynamic ergometer may provide some advantages (reduced risk of injuries), its utilization requires a specific evaluation of physiological responses during an incremental exercise for an adapted management of training. © Georg Thieme Verlag KG Stuttgart · New York.

  18. Astronaut Gerald Carr sits on the bicycle ergometer during prelaunch

    Science.gov (United States)

    1973-01-01

    Astronaut Gerald P. Carr, Skylab 4 mission commander, sits on the bicycle ergometer as he takes part in the body mass measurement experiment during a prelaunch physical examination for the crew of the third manned mission.

  19. Reliability of oscillometric central blood pressure responses to submaximal exercise.

    Science.gov (United States)

    Lim, Weijie; Faulkner, James; Lambrick, Danielle; Stoner, Lee

    2016-06-01

    Central blood pressure responses to exercise may provide clinicians with a superior diagnostic and prognostic tool. However, to be of value in a clinical setting these assessments must be simple to conduct and reliable. Using oscillometric pulse wave analysis (PWA), determine the upper limit for between-day reliability of central SBP (cSBP) and central pressure augmentation (AIx) responses to three progressive stages of submaximal exercise in a cohort of young, healthy participants. Fifteen healthy males [25.8 years (SD 5.7), 23.9 kg/m (SD 2.5)] were tested on three different mornings in a fasted state, separated by a maximum of 14 days. Central hemodynamic variables were assessed on the left upper arm. Participants underwent three progressive stages of submaximal cycling at 50 W (low), 100 W (moderate) and 150 W (moderate-hard). During low and moderate-intensity exercise the intra-class correlation coefficient (ICC) values for cSBP (0.79-0.80) and AIx (0.81-0.85) indicated excellent reliability (ICC > 0.75). For the moderate-hard intensity AIx could not be computed, and the ICC for cSBP was adequate (0.72). Findings from this study suggest that, at least in a young, healthy cohort, oscillometric PWA can be used to reliably assess central blood pressure measurements during exercise, up to a moderate intensity. Although further work is required to verify these findings in clinical cohorts, these measurements may potentially provide clinicians with a practical option for obtaining important hemodynamic information beyond that provided by resting peripheral blood pressure.

  20. Rowing ergometer with the slide is more specific to rowers' physiological evaluation.

    Science.gov (United States)

    De Campos Mello, Fernando; Bertuzzi, Rômulo; Franchini, Emerson; Candau, Robin

    2014-01-01

    This study investigated maximal and submaximal performance (power output) and physiological responses (oxygen uptake, heart rate and blood lactate concentration) of eight male rowers to two different incremental tests to exhaustion performed either in a rowing ergometer without (regular) or with the slide, as well as to a 2000 m race simulation, conducted in a randomized order. Peak oxygen uptake ([Formula: see text]O2peak) was statistically higher (3.4%) in the regular test (5.18 ± 0.44 L.min(-1)) compared with the slide condition (5.01 ± 0.37 L.min(-1); P = 0.005). Time for the on-water race simulation was significantly correlated with the slope of the [Formula: see text]O2-power relationship in the slide condition (r = -0.73, P = 0.043) and [Formula: see text]O2peak during the test in the slide condition was correlated to mean [Formula: see text]O2 at the on-water race simulation (r = 0.78; P = 0.024). Thus, the use of the slide is more beneficial than the regular test when evaluating rowers.

  1. Comparison of ergometer- and track-based testing in junior track-sprint cyclists. Implications for talent identification and development.

    Science.gov (United States)

    Tofari, Paul J; Cormack, Stuart J; Ebert, Tammie R; Gardner, A Scott; Kemp, Justin G

    2017-10-01

    Talent identification (TID) and talent development (TDE) programmes in track sprint cycling use ergometer- and track-based tests to select junior athletes and assess their development. The purpose of this study was to assess which tests are best at monitoring TID and TDE. Ten male participants (16.2 ± 1.1 year; 178.5 ± 6.0 cm and 73.6 ± 7.6 kg) were selected into the national TID squad based on initial testing. These tests consisted of two 6-s maximal sprints on a custom-built ergometer and 4 maximal track-based tests (2 rolling and 2 standing starts) using 2 gear ratios. Magnitude-based inferences and correlation coefficients assessed changes following a 3-month TDE programme. Training elicited meaningful improvements (80-100% likely) in all ergometer parameters. The standing and rolling small gear, track-based effort times were likely and very likely (3.2 ± 2.4% and 3.3 ± 1.9%, respectively) improved by training. Stronger correlations between ergometer- and track-based measures were very likely following training. Ergometer-based testing provides a more sensitive tool than track-based testing to monitor changes in neuromuscular function during the early stages of TDE. However, track-based testing can indicate skill-based improvements in performance when interpreted with ergometer testing. In combination, these tests provide information on overall talent development.

  2. Anaerobic capacity of physically active eumenorrheic females at mid-luteal and mid-follicular phases of ovarian cycle.

    Science.gov (United States)

    Shaharudin, S; Ghosh, A K; Ismail, A A

    2011-12-01

    The present study was undertaken to evaluate the anaerobic capacity in repeated sprint cycling bouts during mid-luteal (ML) and mid-follicular (MF) phases of ovarian cycle. Twelve physically active females aged 22.41±1.68 years, with normal regular menstrual cycle and VO2max of 34.92±4.85 mL·kg-1·min-1 volunteered as subjects in this study. The menstrual phases were verified through daily basal body temperature recording and serum progesterone analysis. Anaerobic capacity was quantified by measuring maximal accumulated oxygen deficit (MAOD). In this study, MAOD was measured following well established method. Initially, the VO2max of the subjects was measured following a graded exercise protocol on a cycle ergometer. On separate days, the subjects performed sub-maximal cycling exercise at 50%, 60%, 70% and 80% of VO2max for 10 minutes. The linear regression determined from the sub-maximal VO2-power relationship was used to estimate the supra-maximal power output at 120% VO2max. The subjects performed repeated sprint cycling for 3 times at 120% of VO2max with 20 minutes rest between consecutive sprints during MF and ML phases. Results indicated there was no significant difference in maximal accumulated oxygen deficit (MAOD) and sprint performance between MF and ML phases in repeated sprint cycling. Serum progesterone was significantly lower in luteal phase after repeated sprints. Hence, it is concluded that the anaerobic capacity is unaffected by ovarian phases in women with regular menstrual cycle. Lower serum progesterone after repeated sprints might be due to the repeated anaerobic activity.

  3. Relação entre indicadores fisiológicos obtidos em teste ergoespirométrico em cicloergômetro de membros superiores e desempenho na canoagem Relationship between physiological indicators obtained in ergospirometry test in cycle ergometer of upper extremities and performance in canoeing

    Directory of Open Access Journals (Sweden)

    Fábio Yuzo Nakamura

    2007-10-01

    , 500 and 1000 m distances. The sample consisted of 12 male athletes (17.6 ± 2.1 years; 175.7 ± 2.5 cm; 68.3 ± 6.3 kg through a test in cycle ergometer of upper extremities for determination of oxygen uptake in the ventilatory threshold 1 (VT1 - 1.8 ± 0.4 L/min, in the ventilatory threshold 2 (VT2 - 2.9 ± 0.4 L/min and VO2peak (3.5 ± 0.4 L/min. The test began with a 17 W load, with 17 W/min increments until voluntary exhaustion. The athletes have been also submitted to specific tests in K-1 individual canoe in a lake, with the purpose to reach the lowest times in the referred distances (times equivalent to 47.6 ± 4.3, 122.0 ± 9.0 and 239.5 ± 12.6 s, respectively. The Spearman-Rank correlation test was used (rs, with significance level set at 5%. Moderate correlation was observed between VT2 and time in the 1000 m (rs = -0.685, VO2peak and time in the 500 m (rs = -0.699 and VO2peak and time in the 1000 m rs = -0.734. Therefore, it is concluded that VT2 and VO2peak obtained in cycle ergometer of upper extremities, and expressed in absolute terms, predict performance in 500 and 1000 m canoeing events and can be potentially applied in evaluation of canoers.

  4. The effect of including a series of isometric conditioning contractions to the rowing warm-up on 1,000-m rowing ergometer time trial performance.

    Science.gov (United States)

    Feros, Simon A; Young, Warren B; Rice, Anthony J; Talpey, Scott W

    2012-12-01

    Rowing requires strength, power, and strength-endurance for optimal performance. A rowing-based warm-up could be enhanced by exploiting the postactivation potentiation (PAP) phenomenon, acutely enhancing power output at the beginning of a race where it is needed most. Minimal research has investigated the effects of PAP on events of longer duration (i.e. 1,000-m rowing). The purpose of this research was to investigate the effects of PAP on 1,000-m rowing ergometer performance through the use of 2 different warm-up procedures: (a) a rowing warm-up combined with a series of isometric conditioning contractions, known as the potentiated warm-up (PW), and (b) a rowing warm-up only (NW). The isometric conditioning contractions in the PW were performed by "pulling" an immovable handle on the rowing ergometer, consisting of 5 sets of 5 seconds (2 seconds at submaximal intensity, and 3 seconds at maximal intensity), with a 15-second recovery between sets. The 1,000-m rowing ergometer time trial was performed after each warm-up condition, whereby mean power output, mean stroke rate, and split time were assessed every 100 m. Ten Australian national level rowers served as the subjects and performed both conditions in a counterbalanced order on separate days. The PW reduced 1,000-m time by 0.8% (p > 0.05). The PW improved mean power output by 6.6% (p rowing warm-up enhance short-term rowing ergometer performance (especially at the start of a race) to a greater extent than a rowing warm-up alone.

  5. Effect of adjusting pulse durations of functional electrical stimulation cycling on energy expenditure and fatigue after spinal cord injury.

    Science.gov (United States)

    Gorgey, Ashraf S; Poarch, Hunter J; Dolbow, David D; Castillo, Teodoro; Gater, David R

    2014-01-01

    The purpose of the current study was to determine the effects of three different pulse durations (200, 350, and 500 microseconds [P200, P350, and P500, respectively]) on oxygen uptake (VO2), cycling performance, and energy expenditure (EE) percentage of fatigue of the knee extensor muscle group immediately and 48 to 72 h after cycling in persons with spinal cord injury (SCI). A convenience sample of 10 individuals with motor complete SCI participated in a repeated-measures design using a functional electrical stimulation (FES) cycle ergometer over a 3 wk period. There was no difference among the three FES protocols on relative VO2 or cycling EE. Delta EE between exercise and rest was 42% greater in both P500 and P350 compared with P200 (p = 0.07), whereas recovery VO2 was 23% greater in P350 compared with P200 (p = 0.03). There was no difference in the outcomes of the three pulse durations on muscle fatigue. Knee extensor torque significantly decreased immediately after (p < 0.001) and 48 to 72 h after (p < 0.001) FES leg cycling. Lengthening pulse duration did not affect submaximal or relative VO2 or EE, total EE, and time to fatigue. Greater recovery VO2 and delta EE were noted in P350 and P500 compared with P200. An acute bout of FES leg cycling resulted in torque reduction that did not fully recover 48 to 72 h after cycling.

  6. Effect of music on submaximal cycling | Schie | South African Journal ...

    African Journals Online (AJOL)

    Objective. Athletes frequently report training to music, yet there have been relatively few studies that have addressed the benefit of exercising with music. Design. Volunteer men and women (N=30), aged between 18 and 40 years, performed an initial familiarisation session. Part of this session involved the measurement of ...

  7. Effect of music on submaximal cycling | Schie | South African Journal ...

    African Journals Online (AJOL)

    South African Journal of Sports Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 20, No 1 (2008) >. Log in or Register to get access to full text downloads.

  8. Stability Ball Sitting versus Chair Sitting During Sub-maximal Arm Ergometry.

    Science.gov (United States)

    Marks, Charles R C; Hylland, Kristina E; Terrell, Jacob

    It was predicted that sitting on a stability ball during arm ergometry would elevate cardiovascular parameters when compared to sitting on a chair and that this would be associated with greater recruitment of trunk and leg skeletal muscles. Open-circuit spirometry, videotaping, blood pressure, heart rate, and EMG were conducted during rest and four minute stages of 15 W, 30 W, and 45 W using a Monark arm ergometer. Twenty-six apparently healthy adults exercised twice, once sitting on a stability ball and the other sitting on a chair (order randomized), with 45 to 60 minutes of rest between. ANOVA for repeated measures and paired-t testing were used for analysis. Oxygen consumption was significantly 10 to 16% higher during exercise while sitting on the stability ball. There were no significant differences between sitting modes for heart rate, SBP, and DBP. Also, resting and exercise rectus femoris and 45 W external oblique EMGs were significantly higher on the stability ball. Finally, the knee was significantly more extended with the feet farther apart and more forward on the stability ball. The stability ball significantly elevates oxygen consumption during sub-maximal arm cranking without significantly increasing heart rate or blood pressure and this is associated with increased thigh muscle activation and lower leg repositioning.

  9. Bicycle ergometer versus treadmill on balance and gait parameters ...

    African Journals Online (AJOL)

    Rasha A. Mohamed

    2014-12-01

    Dec 1, 2014 ... Bicycle ergometer versus treadmill on balance and gait parameters in children with hemophilia. Rasha A. Mohamed *, Abd El-Aziz A. Sherief. Department of Physical Therapy for Disturbance of Growth and Development in Children and its Surgery,. Faculty of Physical Therapy, Cairo University, Cairo, Egypt.

  10. Bicycle ergometer versus treadmill on balance and gait parameters ...

    African Journals Online (AJOL)

    Group A received a designed physical therapy program and aerobic exercise training by bicycle ergometer. While group B received the same physical therapy program in addition to aerobic exercise training by the treadmill. Both groups received treatment sessions three times per week for three successive months. Stability ...

  11. Combining ergometer exercise and artificial gravity in a compact-radius centrifuge

    Science.gov (United States)

    Diaz, Ana; Trigg, Chris; Young, Laurence R.

    2015-08-01

    Humans experience physiological deconditioning during space missions, primarily attributable to weightlessness. Some of these adverse consequences include bone loss, muscle atrophy, sensory-motor deconditioning, and cardiovascular alteration, which may lead to orthostatic intolerance when astronauts return to Earth. Artificial gravity could provide a comprehensive countermeasure capable of challenging all the physiological systems at once, particularly if combined with exercise, thereby maintaining overall health during extended exposure to weightlessness. A new Compact Radius Centrifuge (CRC) platform was designed and built on the existing Short Radius Centrifuge (SRC) at the Massachusetts Institute of Technology (MIT). The centrifuge has been constrained to a radius of 1.4 m, the upper radial limit for a centrifuge to fit within an International Space Station (ISS) module without extensive structural alterations. In addition, a cycle ergometer has been added for exercise during centrifugation. The CRC now includes sensors of foot forces, cardiovascular parameters, and leg muscle electromyography. An initial human experiment was conducted on 12 subjects to analyze the effects of different artificial gravity levels (0 g, 1 g, and 1.4 g, measured at the feet) and ergometer exercise intensities (25 W warm-up, 50 W moderate and 100 W vigorous) on the musculoskeletal function as well as motion sickness and comfort. Foot forces were measured during the centrifuge runs, and subjective comfort and motion sickness data were gathered after each session. Preliminary results indicate that ergometer exercise on a centrifuge may be effective in improving musculoskeletal function. The combination is well tolerated and motion sickness is minimal. The MIT CRC is a novel platform for future studies of exercise combined with artificial gravity. This combination may be effective as a countermeasure to space physiological deconditioning.

  12. Repeatability and Validity of the Combined Arm-Leg (Cruiser) Ergometer

    Science.gov (United States)

    Simmelink, Elisabeth K.; Wempe, Johan B.; Geertzen, Jan H. B.; Dekker, Rienk

    2009-01-01

    The measurement of physical fitness of lower limb amputees is difficult, as the commonly used ergometer tests have limitations. A combined arm-leg (Cruiser) ergometer might be valuable. The aim of this study was to establish the repeatability and validity of the combined arm-leg (Cruiser) ergometer. Thirty healthy volunteers carried out three…

  13. LBNP/ergometer effects on female cardiovascular and muscle deconditioning in 15d head-down bed rest

    Science.gov (United States)

    Wang, Lin-Jie

    2012-07-01

    Female has already been an important part of astronaut corps but gender characteristics in weightlessness and countermeasure effects still not clearly elucidated. In this study the LBNP/Ergometer effects on female cardiovascular deconditioning and muscle atrophy in 15d head-down bed rest were explored. 22 female university students were recruited as volunteers that participated in the 15d head-down bed rest. They were divided into control group (Con,n=8), LBNP exercise group (LBNP,n=7) and LBNP combined with ergometer exercise group (LBNP+Ergo, n=7). Grade negative pressures of -10,-20,-30,-40mmHg 20 or 55min were used in LBNP exercise. In ergometer exercises the subjects must maintain 60-80% VO2peak of pre-bed rest at pedal speed of about 70cycle/min for 15min and the entire exercise duration was 30min. LBNP were performed at 6th,8th,10th,12th,and 13th day and Ergometer were operated at 4th,5th,7th,9th,11th day during bed rest. Before and after bed rest, cardiovascular tilt test were performed to evaluate orthostatic intolerance, supine cycle ergometer were used to test the cardiopulmonary function, MRI tests were operated to examine the volume variations of leg muscle groups and isokinetic test were given to test the muscle strength and endurance of knee. 40% of female subjects did not pass the tilt table test after bed rest and exercises made no difference. Compared with pre-BR, VO2max and VO2max /body weight, VO2/HRmax, maximal power and duration significantly decreased in CON group and LBNP group. For the ERGO+LBNP group, there were no visible different in the parameters of cardiopulmonary function except that maximal power and duration decreased. Muscle maximal voluntary contraction and muscle (quadriceps, rectus femoris, gastrocnemius and soleus) volume decreasing in non-predominant leg was larger in Con group than in LBNP+Ergo group. It is suggested that LBNP combined with ergometer in some degrees can counteract the cardiovascular and muscle deconditioning

  14. Effects of wheel and hand-rim size on submaximal propulsion in wheelchair athletes.

    Science.gov (United States)

    Mason, Barry S; Van Der Woude, Lucas H V; Tolfrey, Keith; Lenton, John P; Goosey-Tolfrey, Victoria L

    2012-01-01

    This study aimed to investigate the effects of fixed gear ratio wheel sizes on the physiological and biomechanical responses to submaximal wheelchair propulsion. Highly trained wheelchair basketball players (N = 13) propelled an adjustable sports wheelchair in three different wheel sizes (24, 25, and 26 inches) on a motor-driven treadmill. Each wheel was equipped with force-sensing hand-rims (SMARTWheel), which collected kinetic and temporal data. Oxygen uptake (V˙O2) and HR responses were measured with high-speed video footage collected to determine three-dimensional upper body joint kinematics. Mean power output and work per cycle decreased progressively with increasing wheel size (P wheelchair propulsion.

  15. Physical exercises on a bicycle-ergometer and running track to prevent hypodynamia in workers of intellectual labor

    Science.gov (United States)

    Vasilyeva, V. V.; Korableva, Y. N.; Trunin, V. V.

    1980-01-01

    A program of exercises was developed and tested, consisting of a 12 minute session on a variable load bicycle ergometer and a 10-11 min. run with brief stretching and resting sessions between. Physical performance capacity was measured before, during, and after the period of the experiment and physical exams conducted. After a 4 month test period involving 30 men, aged 25-35, the program was found to be successful in increasing physical performance capacity. The PWC170 increased an average of 22 percent and maximum oxygen consumption 14 percent. Arterial pressure dropped (120/75 to 114/68), vital capacity of lungs increased by 6 percent, strength of respiratory muscles by 8.8 percent, duration of respiratory delay by 18 percent. Duration of cardiac cycles increased, stress index decreased. Cardiac contraction rate 2 minutes after work on the ergometer decreased from 118 to 102 bt/min.

  16. MOTION CAPTURE AS A MODERN TECHNOLOGY FOR ANALYSING ERGOMETER ROWING

    Directory of Open Access Journals (Sweden)

    Maria Skublewska-Paszkowska

    2016-03-01

    Full Text Available The paper presents a purpose-built laboratory stand consisting of a Vicon motion capture system with reference video cameras, wireless EMG system, Concept 2 Indoor Rower ergometer, wireless heart rate monitor and the Nexus software. A pilot study of people who exercise on the ergometer helped to create a proper configuration of all the components of the laboratory. Moreover, a procedure for carrying out research was developed, which consists of several steps divided into 4 stages: preparation of the motion acquisition system; preparation of the participant; familiarising participants with the technique of rowing, recording their movements and acquiring other measurement signals. Preliminary analysis of the results obtained from heterogeneous signals from various devices showed that all the components of the research stand are mutually compatible and the received signals do not interfere with one another.

  17. Design Analysis And Applications Of A Regenerative Bicycle Ergometer

    Directory of Open Access Journals (Sweden)

    Chukwuneke J. L.

    2015-08-01

    Full Text Available Man needs to do some form of physical work in other to remain healthy this work is similar to the work done by any machine or equipment and thus should be channeled to give useful output but rather it is usually dissipated into the environment in form of heat. The regenerative bicycle ergometer takes advantage of the greater power generated by the limbs and arms thus conserves converts and stores the energy dissipated by the rider with an ideal mechanical advantage of 7.6 it strategically uses simple mechanisms to magnify its work and then converts this mechanical energy into electrical energy by the use of a dynamo with a speed ratio of 108.5 and a transmission efficiency of 89 the rider pedals 27rpm to obtain the dynamos rated input of 2600rpm giving an output of 12.6volts. The regenerative bicycle ergometer is designed and constructed to perform all the core functions of a bicycle ergometer having an allowable load of 116.5kg and a maximum resistance of 65.33N which is equivalent to a mass of 6.66kg. The energy converted is stored in a 12volts battery making its use flexible clean and meeting the energy demands of man.

  18. Differences in spinopelvic kinematics in sweep and scull ergometer rowing.

    Science.gov (United States)

    Strahan, Alexander D; Burnett, Angus F; Caneiro, Joao Paulo; Doyle, Matthew M; O'Sullivan, Peter B; Goodman, Carmel

    2011-07-01

    The spinopelvic kinematics of sweep and scull have yet to be investigated, despite evidence suggesting that sweep rowing may be provocative for low back pain (LBP). The aim of this study was to determine whether differences existed in spinopelvic kinematics in high-level rowers without LBP in sweep and scull ergometer rowing. Repeated measures study. Institute of Sport Laboratory. Ten high-level rowers. Kinematics of the pelvis, lower lumbar, upper lumbar, and lower thoracic regions during the drive phase of the rowing stroke were measured while rowing on an interchangeable sweep/scull ergometer. Total and segmental spinopelvic kinematics. Sweep rowing showed greater lateral bend (P rowing displayed a greater magnitude (P rowing showed values close to end range flexion for the lower lumbar spine at the catch and early drive phases. No difference (P > 0.05) was evident in lateral bend or axial rotation values for the lower lumbar region. Some differences exist in spinopelvic kinematics between sweep and scull ergometer rowing. However, it may be speculated that the lack of differences in lateral bend and axial rotation at the lower lumbar spine in sweep rowing may represent an adaptive and protective approach of experienced rowers. This may be the focus of future research studies.

  19. F-door spaces and F-submaximal spaces

    Directory of Open Access Journals (Sweden)

    Lobna Dridi

    2013-04-01

    Full Text Available Submaximal spaces and door spaces play an enigmatic role in topology. In this paper, reinforcing this role, we are concerned with reaching two main goals: The first one is to characterize topological spaces X such that F(X is a submaximal space (resp., door space for some covariant functor Ff rom the category Top to itself. T0, and FH functors are completely studied. Secondly, our interest is directed towards the characterization of maps f given by a flow (X, f in the category Set, such that (X,P(f is submaximal (resp., door where P(f is a topology on X whose closed sets are exactly the f-invariant sets.

  20. Caffeine improves supramaximal cycling but not the rate of anaerobic energy release.

    Science.gov (United States)

    Simmonds, Michael J; Minahan, Clare L; Sabapathy, Surendran

    2010-05-01

    The purpose of this study was to determine if improved supramaximal exercise performance in trained cyclists following caffeine ingestion was associated with enhanced O(2) uptake (VO2 kinetics), increased anaerobic energy provision (accumulated O(2)-AO(2)-deficit), or a reduction in the accumulation of metabolites (for example, K(+)) associated with muscular fatigue. Six highly trained male cyclists (VO2peak 68 +/- 8 mL kg(-1) min(-1)) performed supramaximal (120% VO2peak) exercise bouts to exhaustion on an electronically braked cycle ergometer, following double-blind and randomized ingestion of caffeine/placebo (5 mg kg(-1)). Time to exhaustion (TE), VO2 kinetics, AO(2) deficit, blood lactate (La(-)), plasma potassium (K(+)), caffeine and paraxanthine concentrations were measured. Caffeine ingestion elicited significant increases in TE (14.8%, p caffeine ingestion. However, [K(+)] was significantly reduced (13.4%, p caffeine trials, compared with placebo. It appears that caffeine ingestion is beneficial to supramaximal cycling performance in highly trained men. The reduced plasma [K(+)] during submaximal warm-up cycling may prolong the time taken to reach critical [K(+)] at exhaustion, thus delaying fatigue. Considering caffeine ingestion did not change VO2 kinetics or isotime AO(2) deficit, increases in absolute AO(2) deficit may be a consequence of prolonged TE, rather than causal.

  1. Indirect Methods of Assessing Maximal Oxygen Uptake in Rowers: Practical Implications for Evaluating Physical Fitness in a Training Cycle

    Directory of Open Access Journals (Sweden)

    Klusiewicz Andrzej

    2016-04-01

    Full Text Available The aim of the study was to evaluate the usefulness of indirect methods of assessment of VO2max for estimation of physical capacity of trained male and female rowers during a training cycle. A group of 8 female and 14 male rowers performed the maximal intensity test simulating the regatta distance (a 2 km test and a submaximal incremental exercise test on a rowing ergometer. The suitability of the indirect methods of predicting VO2max during the training cycle was evaluated by performing the tests twice: in females at an interval of five months and in males at an interval of seven months. To indirectly estimate VO2max, regression formulas obtained for the linear relationship between the examined effort indices were utilized based on 1 mean power obtained in the 2 km test, and 2 submaximal exercises after the estimation of PWC170. Although the suitability of the two indirect methods of assessment of VO2max was statisticaly confirmed, their usefulness for estimation of changes in physical fitness of trained rowers during the training cycle was rather low. Such an opinion stems from the fact that the total error of these methods (range between 4.2-7.7% in female and 5.1-7.4% in male rowers was higher than the real differences in VO2max values determined in direct measurements (between the first and the second examination maximal oxygen uptake rose by 3.0% in female rowers and decreased by 4.3% in male rowers.

  2. A SYSTEMATIC REVIEW AND META-ANALYSIS COMPARING CARDIOPULMONARY EXERCISE TEST VALUES OBTAINED FROM THE ARM CYCLE AND THE LEG CYCLE RESPECTIVELY IN HEALTHY ADULTS

    DEFF Research Database (Denmark)

    Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

    2016-01-01

    INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...

  3. A Systematic Review and Meta-analysis Comparing Cardiopulmonary Exercise Test Values Obtained From the Arm Cycle and the Leg Cycle Respectively in Healthy Adults

    DEFF Research Database (Denmark)

    Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

    2016-01-01

    INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...

  4. A systematic review and meta-analysis comparing cardiopulmonary exercise test values obtained from the arm cycle and the leg cycle respectively in healthy adults

    DEFF Research Database (Denmark)

    Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

    2016-01-01

    INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...

  5. Effects of submaximal and supramaximal interval training on determinants of endurance performance in endurance athletes.

    Science.gov (United States)

    Paquette, M; Le Blanc, O; Lucas, S J E; Thibault, G; Bailey, D M; Brassard, P

    2017-03-01

    We compared the effects of submaximal and supramaximal cycling interval training on determinants of exercise performance in moderately endurance-trained men. Maximal oxygen consumption (VO2max ), peak power output (Ppeak ), and peak and mean anaerobic power were measured before and after 6 weeks (3 sessions/week) of submaximal (85% maximal aerobic power [MP], HIIT85 , n = 8) or supramaximal (115% MP, HIIT115 , n = 9) interval training to exhaustion in moderately endurance-trained men. High-intensity training volume was 47% lower in HIIT115 vs HIIT85 (304 ± 77 vs 571 ± 200 min; P training was generally associated with increased VO2max (HIIT85 : +3.3 ± 3.1 mL/kg/min; HIIT115 : +3.3 ± 3.6 ml/kg/min; Time effect P = 0.002; Group effect: P = 0.95), Ppeak (HIIT85 : +18 ± 9 W; HIIT115 : +16 ± 27 W; Time effect P = 0.045; Group effect: P = 0.49), and mean anaerobic power (HIIT85 : +0.42 ± 0.69 W/kg; HIIT115 : +0.55 ± 0.65 W/kg; Time effect P = 0.01; Group effect: P = 0.18). Six weeks of submaximal and supramaximal interval training performed to exhaustion seems to equally improve VO2max and anaerobic power in endurance-trained men, despite half the accumulated time spent at the target intensity. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Differential contributions of ankle plantarflexors during submaximal isometric muscle action

    DEFF Research Database (Denmark)

    Masood, Tahir; Bojsen-Møller, Jens; Kalliokoski, Kari K

    2014-01-01

    The objective of this study was to investigate the relative contributions of superficial and deep ankle plantarflexors during repetitive submaximal isometric contractions using surface electromyography (SEMG) and positron emission tomography (PET). Myoelectric signals were obtained from twelve....... The findings of this study provide valuable reference for studies where individual muscle contributions are estimated using models and simulations....

  7. Myocardial oxygen consumption at rest and during submaximal ...

    African Journals Online (AJOL)

    olayemitoyin

    2008-11-26

    Nov 26, 2008 ... Department of Physiology, JSS Medical College, Constituent College of JSS University, Mysore – 570015, ... determine the effect of increased adiposity on myocardial oxygen consumption at rest and during submaximal exercise in ... during exercise suggesting higher hemodynamic stress to the heart.

  8. An Investigation into Submaximal Endurance in Children with Motor ...

    African Journals Online (AJOL)

    This study investigated the submaximal endurance levels of children with motor difficulties, using the six-minute walk test (6MWT). A prospective, cross-sectional study was conducted. Forty-eight children between ages seven and ten years were enrolled. They came from similar socio-economic backgrounds and attended ...

  9. Myocardial oxygen consumption at rest and during submaximal ...

    African Journals Online (AJOL)

    Overweight and obesity are major risk factors for cardiovascular diseases. The objective of this study was to determine the effect of increased adiposity on myocardial oxygen consumption at rest and during submaximal exercise in young adults. The study consisted of 85 young adults (18-22years) grouped into 3 based on ...

  10. Influence of menstrual phase on ventilatory response to submaximal ...

    African Journals Online (AJOL)

    Objectives. To determine whether an increase in respiratory drive, due to elevated progesterone and oestrogen concentration during various menstrual phases, persists throughout prolonged submaximal exercise and potentially contributes to fatigue. Furthermore, to determine whether the difference in the ventilatory ...

  11. Myocardial oxygen consumption at rest and during submaximal ...

    African Journals Online (AJOL)

    olayemitoyin

    2008-11-26

    Nov 26, 2008 ... and myocardial fatty acid utilization has been showed to decrease after weight loss from gastric bypass surgery or diet in obese persons (Fei ho et al., 1995,). During submaximal exercise and immediately after exercise, all three groups showed an increase in. RPP. The percentage increase in RPP was.

  12. Design Analysis And Applications Of A Regenerative Bicycle Ergometer

    OpenAIRE

    Chukwuneke J. L.; Ugwuegbu D. C.; Sinebe J. E.; Enyi L. C.

    2015-01-01

    Man needs to do some form of physical work in other to remain healthy this work is similar to the work done by any machine or equipment and thus should be channeled to give useful output but rather it is usually dissipated into the environment in form of heat. The regenerative bicycle ergometer takes advantage of the greater power generated by the limbs and arms thus conserves converts and stores the energy dissipated by the rider with an ideal mechanical advantage of 7.6 it strategically use...

  13. Development and Validation of an Automated Step Ergometer

    Directory of Open Access Journals (Sweden)

    C. de Sousa Maria do Socorro

    2014-12-01

    Full Text Available Laboratory ergometers have high costs, becoming inaccessible for most of the population, hence, it is imperative to develop affordable devices making evaluations like cardiorespiratory fitness feasible and easier. The objective of this study was to develop and validate an Automated Step Ergometer (ASE, adjusted according to the height of the subject, for predicting VO2max through a progressive test. The development process was comprised by three steps, the theoretical part, the prototype assembly and further validation. The ASE consists in an elevating platform that makes the step at a higher or lower level as required for testing. The ASE validation was obtained by comparing the values of predicted VO2max (equation and direct gas analysis on the prototype and on a, treadmill. For the validation process 167 subjects with average age of 31.24 ± 14.38 years, of both genders and different degrees of cardiorespiratory fitness, were randomized and divided by gender and training condition, into untrained (n=106, active (n=24 and trained (n=37 subjects. Each participant performed a progressive test on which the ASE started at the same height (20 cm for all. Then, according to the subject’s height, it varied to a maximum of 45 cm. Time in each stage and rhythm was chosen in accordance with training condition from lowest to highest (60-180 s; 116-160 bpm, respectively. Data was compared with the student’s t test and ANOVA; correlations were tested with Pearson’s r. The value of α was set at 0.05. No differences were found between the predicted VO2max and the direct gas analysis VO2max, nor between the ASE and treadmill VO2max (p= 0.365 with high correlation between ergometers (r= 0.974. The values for repeatability, reproducibility, and reliability of male and female groups measures were, respectively, 4.08 and 5.02; 0.50 and 1.11; 4.11 and 5.15. The values of internal consistency (Cronbach’s alpha among measures were all >0.90. It was verified

  14. Kinematic asymmetries of the lower limbs during ergometer rowing.

    Science.gov (United States)

    Buckeridge, Erica; Hislop, Simon; Bull, Anthony; McGregor, Alison

    2012-11-01

    Rowing injuries, particularly of the lumbar spine, are often attributed to poor technique. Rowing technique comprises a series of coordinated movements between the back, upper limbs, and lower limbs, and abnormalities in these may lead to injury. The aim of this study was to test the hypothesis that ergometer rowing is symmetrical with respect to lower limb motion and that deviations from symmetry result from rowing experience, work rate, or stroke position. Twenty-two rowers in three levels of ability participated in this study. A motion analysis system was used with an instrumented rowing ergometer, which incorporated load cells at the handle and seat. Kinematic measurements of the knees, hips, lumbar-pelvic joints, and pelvic twist, in addition to measures of handle force, seat force, stroke length, mediolateral seat drift, and mean external power, were made during an incremental step test. Elite rowers exhibited the largest handle force and mean external power (P rowing stroke, particularly at the hips, can contribute to suboptimal kinematics of the lumbar-pelvic region. Quantification of hip ROM asymmetries may therefore be a useful tool in predicting the development of low back pain in rowers.

  15. Effect of the aerobic capacity on the validity of the anaerobic threshold for determination of the maximal lactate steady state in cycling

    Directory of Open Access Journals (Sweden)

    B.S. Denadai

    2004-10-01

    Full Text Available The maximal lactate steady state (MLSS is the highest blood lactate concentration that can be identified as maintaining a steady state during a prolonged submaximal constant workload. The objective of the present study was to analyze the influence of the aerobic capacity on the validity of anaerobic threshold (AT to estimate the exercise intensity at MLSS (MLSS intensity during cycling. Ten untrained males (UC and 9 male endurance cyclists (EC matched for age, weight and height performed one incremental maximal load test to determine AT and two to four 30-min constant submaximal load tests on a mechanically braked cycle ergometer to determine MLSS and MLSS intensity. AT was determined as the intensity corresponding to 3.5 mM blood lactate. MLSS intensity was defined as the highest workload at which blood lactate concentration did not increase by more than 1 mM between minutes 10 and 30 of the constant workload. MLSS intensity (EC = 282.1 ± 23.8 W; UC = 180.2 ± 24.5 W and AT (EC = 274.8 ± 24.9 W; UC = 187.2 ± 28.0 W were significantly higher in trained group. However, there was no significant difference in MLSS between EC (5.0 ± 1.2 mM and UC (4.9 ± 1.7 mM. The MLSS intensity and AT were not different and significantly correlated in both groups (EC: r = 0.77; UC: r = 0.81. We conclude that MLSS and the validity of AT to estimate MLSS intensity during cycling, analyzed in a cross-sectional design (trained x sedentary, do not depend on the aerobic capacity.

  16. Cerebral blood flow during submaximal and maximal dynamic exercise in humans

    DEFF Research Database (Denmark)

    Thomas, S N; Schroeder, T; Secher, N H

    1989-01-01

    Cerebral blood flow (CBF) in humans was measured at rest and during dynamic exercise on a cycle ergometer corresponding to 56% (range 27-85) of maximal O2 uptake (VO2max). Exercise bouts were performed by 16 male and female subjects, lasted 15 min each, and were carried out in a semisupine position....... CBF (133Xe clearance) was expressed as the initial slope index (ISI) and as the first compartment flow (F1). CBF at rest [ISI, 58 (range 45-73); F1, 76 (range 55-98) ml.100 g-1.min-1] increased during exercise [ISI to 79 (57-94) and F1 to 118 (75-164) ml.100 g-1.min-1, P less than 0.01]. CBF did...

  17. Gross efficiency and energy expenditure in kayak ergometer exercise.

    Science.gov (United States)

    Gomes, B B; Mourão, L; Massart, A; Figueiredo, P; Vilas-Boas, J P; Santos, A M C; Fernandes, R J

    2012-08-01

    We purposed to study energy expenditure, power output and gross efficiency during kayak ergometer exercise in 12 elite sprint kayakers. 6 males (age 24.2±4.8 years, height 180.4±4.8 cm, body mass 79.7±8.5 kg) and 6 females (age 24.3±4.5 years, height 164.5±3.9 cm, body mass 65.4±3.5 kg), performed an incremental intermittent protocol on kayak ergometer with VO2 and blood lactate concentration assessment, a non-linear increase between power output and energy expenditure being observed. Paddling power output, energy expenditure and gross efficiency corresponding to VO2max averaged 199.92±50.41 W, 75.27±6.30 ml.kg - 1.min - 1, and 10.10±1.08%. Male kayakers presented higher VO2max, power output and gross efficiency at the VO2max, and lower heart rate and maximal lactate concentration than females, but no differences were found between genders regarding energy expenditure at VO2max. Aerobic and anaerobic components of energy expenditure evidenced a significant contribution of anaerobic energy sources in sprint kayak performance. Results also suggested the dependence of the gross efficiency on the changes in the amount of the aerobic and anaerobic contributions, at heavy and severe intensities. The inter-individual variance of the relationship between energy expenditure and the corresponding paddling power output revealed a relevant tracking for females (FDγ=0.73±0.06), conversely to the male group (FDγ=0.27±0.08), supporting that some male kayakers are more skilled in some paddling intensities than others. © Georg Thieme Verlag KG Stuttgart · New York.

  18. Aerobic interval training reduces vascular resistances during submaximal exercise in obese metabolic syndrome individuals.

    Science.gov (United States)

    Mora-Rodriguez, Ricardo; Fernandez-Elias, V E; Morales-Palomo, F; Pallares, J G; Ramirez-Jimenez, M; Ortega, J F

    2017-08-12

    The aim of this study was to determine the effects of high-intensity aerobic interval training (AIT) on exercise hemodynamics in metabolic syndrome (MetS) volunteers. Thirty-eight, MetS participants were randomly assigned to a training (TRAIN) or to a non-training control (CONT) group. TRAIN consisted of stationary interval cycling alternating bouts at 70-90% of maximal heart rate during 45 min day(-1) for 6 months. CONT maintained baseline physical activity and no changes in cardiovascular function or MetS factors were detected. In contrast, TRAIN increased cardiorespiratory fitness (14% in VO2PEAK; 95% CI 9-18%) and improved metabolic syndrome (-42% in Z score; 95% CI 83-1%). After TRAIN, the workload that elicited a VO2 of 1500 ml min(-1) increased 15% (95% CI 5-25%; P < 0.001). After TRAIN when subjects pedaled at an identical submaximal rate of oxygen consumption, cardiac output increased by 8% (95% CI 4-11%; P < 0.01) and stroke volume by 10% (95% CI, 6-14%; P < 0.005) being above the CONT group values at that time point. TRAIN reduced submaximal exercise heart rate (109 ± 15-106 ± 13 beats min(-1); P < 0.05), diastolic blood pressure (83 ± 8-75 ± 8 mmHg; P < 0.001) and systemic vascular resistances (P < 0.01) below CONT values. Double product was reduced only after TRAIN (18.2 ± 3.2-17.4 ± 2.4 bt min(-1) mmHg 10(-3); P < 0.05). The data suggest that intense aerobic interval training improves hemodynamics during submaximal exercise in MetS patients. Specifically, it reduces diastolic blood pressure, systemic vascular resistances, and the double product. The reduction in double product, suggests decreased myocardial oxygen demands which could prevent the occurrence of adverse cardiovascular events during exercise in this population. CLINICALTRIALS. NCT03019796.

  19. The effect of menstruation on chosen physiological and biochemical reactions caused by the physical effort with the submaximal intensity

    Directory of Open Access Journals (Sweden)

    P Zieliński

    2003-03-01

    Full Text Available The aim of this work was to determine the influence of the menstruation phase on changes of respective indicators of the gas exchange and on biochemical parameters of blood during physical efforts with the sub-maximal intensity. Fifteen female students of the Academy of Physical Education took part in the study. Girls were aged from 19 to 22 years old and did not practice sports. The effort tests were conducted in the follicular and luteal phase of two succeeding menstrual cycles. As far the aerobic capacity determination is concerned, one cyclo-ergometric test with graded effort was conducted and it was performed till the “refusal”. It allowed to mark a threshold (TDMA and a maximal level of physiological and biochemical indicators. Basing on the results of the graded test individual loads were determined for every next effort trial (repeated 4 times in every phase of the two succeeding menstrual cycles. The aim of this trial was to evaluate the reaction of women’s constitution on work with the sub-maximal intensity. The above trial consisted on two 10 min efforts divided with the 2 min pause (the first effort with the intensity of 80% of the TDMA threshold, second with the intensity bigger about 30-40% of difference between TDMA and a maximal load established by the graded test. The research did not reveal statistically significant differentiation as considering effort changes of basic physiological and biochemical indicators, determining reaction of women’s organisms on work with the sub- and over- threshold intensity (TDMA. It showed that menstruation has not significant effect on the level of changes of analysed parameters caused by the physical effort with the sub-maximal intensity.

  20. Cardiovascular and metabolic responses during indoor climbing and laboratory cycling exercise in advanced and élite climbers.

    Science.gov (United States)

    Limonta, Eloisa; Brighenti, Alfredo; Rampichini, Susanna; Cè, Emiliano; Schena, Federico; Esposito, Fabio

    2018-02-01

    To validate heart rate (f H ) as an effective indicator of the aerobic demands of climbing, the f H vs oxygen uptake ([Formula: see text]) relationship determined during cycling exercise and climbing on a circular climbing treadwall was compared. Possible differences in maximum aerobic characteristics between advanced and élite climbers were also assessed. Seven advanced and six élite climbers performed a discontinuous incremental test on a cycle ergometer and a similar test on a climbing treadwall. Cardiorespiratory and gas exchange parameters were collected at rest and during exercise. The f H vs [Formula: see text] relationship was steeper during cycling than climbing at submaximal exercise for both groups and during climbing in the élite climbers as compared to the advanced. At peak exercise, [Formula: see text] was similar during both cycling and climbing (3332 ± 115 and 3193 ± 129 ml/min, respectively). Despite similar [Formula: see text], the élite climbers had a higher peak workload during climbing (11.8 ± 0.8 vs 9.2 ± 0.3 m/min in élite and advanced climbers, respectively; P = .024) but not during cycling (291 ± 13 and 270 ± 12 W in élite and advanced climbers, respectively). Our findings indicate that care should be taken when energy expenditure during climbing is estimated from the f H vs [Formula: see text] relationship determined in the laboratory. The level of climbing experience significantly affects the energy cost of exercise. Last, the similar aerobic demands of cycling and climbing at peak exercise, suggest that maximum [Formula: see text]may play an important role in climbing performance. Specific training methodologies should be implemented to improve aerobic power in climbers.

  1. Feasibility of Virtual Reality Augmented Cycling for Health Promotion of People Post-Stroke

    Science.gov (United States)

    Deutsch, Judith E; Myslinski, Mary Jane; Kafri, Michal; Ranky, Richard; Sivak, Mark; Mavroidis, Constantinos; Lewis, Jeffrey A

    2013-01-01

    Background and Purpose A virtual reality (VR) augmented cycling kit (VRACK) was developed to address motor control and fitness deficits of individuals with chronic stroke. In this paper we report on the safety, feasibility and efficacy of using the VRACK to train cardio-respiratory (CR) fitness of individuals in the chronic phase poststroke. Methods Four individuals with chronic stroke (47–65 years old and three or more years post-stroke), with residual lower extremity impairments (Fugl Meyer 24–26/34) who were limited community ambulators (gait speed range 0.56 to 1.1 m/s) participated in this study. Safety was defined as the absence of adverse events. Feasibility was measured using attendance, total exercise time, and “involvement” measured with the Presence Questionnaire (PQ). Efficacy of CR fitness was evaluated using a sub-maximal bicycle ergometer test before and after an 8-week training program. Results The intervention was safe and feasible with participants having 1 adverse event, 100% adherence, achieving between 90 and 125 minutes of cycling each week and a mean PQ score of 39 (SD 3.3). There was a statistically significant 13% (p = 0.035) improvement in peak VO2 with a range of 6–24.5 %. Discussion and Conclusion For these individuals post-stroke, VR augmented cycling, using their heart rate to set their avatar’s speed, fostered training of sufficient duration and intensity to promote CR fitness. In addition, there was a transfer of training from the bicycle to walking endurance. VR augmented cycling may be an addition to the therapist’s tools for concurrent training of mobility and health promotion of individuals post-stroke. Video Abstract available (see Video, Supplemental Digital Content 1) for more insights from the authors. PMID:23863828

  2. Fatigue and physical function after hysterectomy measured by SF-36, ergometer, and dynamometer.

    Science.gov (United States)

    Lauszus, Finn F; Kallfa, Ervin; Madsen, Mogens R

    2016-07-01

    Information is limited on the early postoperative rehabilitation following hysterectomy. Our purpose was to evaluate the different perioperative modalities of fatigue, pain, quality of life, and physical performance and their time-related. A prospective, follow-up study of a cohort of women undergoing abdominal and vaginal hysterectomy at the Gynecology Department at Herning Hospital, Denmark. Data from 108 women with elective hysterectomy were compared pre- and postoperatively. The fatigue level was scored on a visual analogue scale and SF-36. Objective measurements were performed by dynamometer of hand grip, knee extension strength, and postural stability; further, by ergometer cycle work capacity and by impedance lean body mass. Quality of life was assessed using the SF-36 questionnaire. Patients were examined preoperatively and twice postoperatively. Women lost lean body mass 13 and 30 days after their hysterectomy (p SF-36 revealed that the modality of 'physical functioning' and 'role limitations due to physical problems' remained significantly decreased at the end of the study (p SF-36 30 days after surgery. No impairment of performance was found in physical tests at days 13 and 30 postoperatively.

  3. Physiological responses and exercise preference between the Trikke and the bicycle ergometer

    Directory of Open Access Journals (Sweden)

    Eddie T.C. Lam

    2016-06-01

    Conclusion: Participants were more efficient in using the Trikke than the bicycle ergometer. The Trikke may be an enjoyable alternative for those individuals, particularly women, who have lost interest in traditional forms of exercise.

  4. Cardiac Autonomic Function during Submaximal Treadmill Exercise in Adults with Down Syndrome

    Science.gov (United States)

    Mendonca, Goncalo V.; Pereira, Fernando D.; Fernhall, Bo

    2011-01-01

    This study determined whether the cardiac autonomic function of adults with Down syndrome (DS) differs from that of nondisabled persons during submaximal dynamic exercise. Thirteen participants with DS and 12 nondisabled individuals performed maximal and submaximal treadmill tests with metabolic and heart rate (HR) measurements. Spectral analysis…

  5. Is energy expenditure taken into account in human sub-maximal jumping? - a simulation study

    NARCIS (Netherlands)

    Vanrenterghem, J.; Bobbert, M.F.; Casius, L.J.R.; de Clercq, D.

    2008-01-01

    This paper presents a simulation study that was conducted to investigate whether the stereotyped motion pattern observed in human sub-maximal jumping can be interpreted from the perspective of energy expenditure. Human sub-maximal vertical countermovement jumps were compared to jumps simulated with

  6. Effect of the Canadian Air Force training programme on a submaximal exercise test.

    Science.gov (United States)

    Kappagoda, C T; Linden, R J; Newell, J P

    1979-07-01

    Validation of the submaximal heart rate/oxygen consumption relationship as an index of 'cardiorespiratory fitness' requires the demonstration of systematic alterations in this relationship concomitant with interventions designed to alter physical fitness. To fulfil those criteria a longitudinal training/de-training study was undertaken. Previously sedentary adult subjects undertook the Canadian Airforce 5BX-XBX exercise programme. Submaximal exercise tests were performed before and after training, and following several weeks cessation of training. A regression line of submaximal heart rate on submaximal oxygen consumption was calculated from the data of each submaximal exercise test. Alterations in the regression lines were examined for each subject individually by testing statistically for difference in slope and elevation between any pair of lines. Subjects who undertook the training/de-training study demonstrated significant systematic alterations in the elevation of the regression lines concomitant with periods of training and de-training. The reproducibility of the submaximal heart rate/oxygen consumption relationship was examined in two additional groups of subjects. Group A repeated a submaximal test on 3 or 4 successive days; Group B were tested before and after 16 weeks of normal activity. Subjects in Group A demonstrated non significant, random alterations in the regression lines on repeated testing and subjects in Group B demonstrated random, though on occasion significant, alterations in the regression lines. The elevation of the submaximal heart rate/oxygen consumption relationship is therefore a valid index for detecting sequential changes in 'cardiorespiratory fitness' in individual subjects.

  7. EFFECT OF KAYAK ERGOMETER ELASTIC TENSION ON UPPER LIMB EMG ACTIVITY AND 3D KINEMATICS

    OpenAIRE

    Neil Fleming; Bernard Donne; David Fletcher

    2012-01-01

    Despite the prevalence of shoulder injury in kayakers, limited published research examining associated upper limb kinematics and recruitment patterns exists. Altered muscle recruitment patterns on-ergometer vs. on-water kayaking were recently reported, however, mechanisms underlying changes remain to be elucidated. The current study assessed the effect of ergometer recoil tension on upper limb recruitment and kinematics during the kayak stroke. Male kayakers (n = 10) performed 4 by 1 min on-e...

  8. Metabolic and cardiorespiratory responses in young oarsmen during prolonged exercise tests on a rowing ergometer at power outputs corresponding to two concepts of anaerobic threshold.

    Science.gov (United States)

    Bourgois, J; Vrijens, J

    1998-01-01

    A group of ten young experienced oarsmen [mean age 17.5 (SD 1.7) years, height 182.5 (SD 5.9) cm, body mass 77.0 (SEM 10.6) kg] exercised in a progressive incremental test (PIE: 50W x 3 min[-1]) on a rowing ergometer to determine the power output corresponding to the 4 mmol lactate x l(-1) anaerobic threshold (AT4) and the individual anaerobic threshold (IAT). Within 10 days they performed at random two 30-min prolonged exercise tests (PET) at power outputs corresponding to AT4 and IAT to demonstrate whether or not a steady-state blood lactate concentration [La-]b could be maintained. Oxygen uptake (VO2), heart rate (HR) and [La-]b were measured. The PIE revealed significant lower values at IAT compared to AT4 for power output (P concepts of anaerobic threshold gave different information about submaximal endurance capacity. Only IAT represented on average [La-]ss. It is suggested that more research is needed to elicit optimal guidelines for the intensity of endurance training.

  9. Blood lactate and hormonal responses to prototype flywheel ergometer workouts.

    Science.gov (United States)

    Caruso, John F; Coday, Michael A; Monda, Julie K; Ramey, Elizabeth S; Hastings, Lori P; Vingren, Jakob L; Potter, William T; Kraemer, William J; Wickel, Eric E

    2010-03-01

    The purpose of the study was to compare blood lactate and hormonal responses with flywheel ergometer (FERG) leg presses for preliminary assessment of workouts best suited for future in-flight resistance exercise. Comprised of 10 repetition sets, the workouts entailed 3 sets of concentric and eccentric (CE3) actions, or concentric-only actions done for 3 (CO3) or 6 (CO6) sets. Methods employed included assessment of blood lactate concentrations ([BLa-]) before and 5 minutes postexercise. Venous blood was also collected before and at 1 and 30 minutes postexercise to assess growth hormone, testosterone, cortisol concentrations ([GH], [T], [C]) and [T/C] ratios. [BLa-] were compared with 2 (time) x 3 (workout) analysis of variance. Hormones were assessed with 2 (gender) x 3 (time) x 3 (workout) analysis of covariances. Results showed [BLa-] had a time effect. Growth hormone concentration showed gender x workout, gender x time, and workout x time interactions, whereas [T] had a 3-way interaction. [C] had gender, time, and workout effects. [T/C] yielded a gender x time interaction. It was concluded that, because CO6 and CE3 yielded similar anabolic hormonal data but the latter had a lower [C] 30 minutes postexercise, CE3 served as the best workout. Although the FERG was originally designed for microgravity, the effort put forth by current subjects was like that for workouts aimed at greater athletic performance and conditioning. Practical applications suggest that eccentric actions should be used for FERG workouts geared toward muscle mass and strength improvement.

  10. "Tailored" submaximal step test for VO2max prediction in healthy older adults.

    Science.gov (United States)

    Pogliaghi, Silvia; Bellotti, Cecilia; Paterson, Donald H

    2014-04-01

    The authors developed and validated a "tailored" version of the Astrand-Rhyming step test (tA-R) and a new equation for VO2max prediction in older adults (OA). Sixty subjects (age 68 ± 4 yr, 30 male, 30 female) performed their tA-R step test (5-min, 30-cm step, tailored stepping rate) and an incremental cycling test to exhaustion. VO2max was (a) predicted using the standard A-R equation (predicted VO2max), (b) predicted based on the authors' new multiple linear equation (equation VO2max), and (c) directly measured by incremental cycling test (direct VO2max). Agreement among values of VO2max was evaluated by Bland-Altman analysis. The predicted VO2max was not significantly different from the direct VO2max, yet with relatively large imprecision. The equation VO2max allowed more precise as well as accurate predictions of VO2max compared with standard A-R prediction. The "tailored" version of the Astrand-Rhyming step test and the new prediction equation appear suitable for a rapid (5-min), safe (submaximal), accurate, and precise VO2max prediction in healthy OA.

  11. The effect of maximal vs submaximal exertion on postprandial lipid levels in individuals with and without coronary heart disease.

    Science.gov (United States)

    Aronov, David M; Bubnova, Marina G; Perova, Natalia V; Orekhov, Alexander N; Bobryshev, Yuri V

    Decisions about fat consumption and levels of physical activity are among the everyday choices we make in life and risk of coronary heart disease (CHD) can be affected by those choices. The purpose of this study was to investigate the influence of a standard fat load combined with physical exertion of different intensities on the plasma lipid profile of CHD patients and CHD-free individuals. This study looked at the influence of different intensities of physical exercise on postprandial lipid metabolism in 20 healthy men and 36 men with diagnosis of CHD. Venous blood samples were obtained after overnight fasting, 3 hours after standard fat load (before the physical load), and immediately after maximal or submaximal physical exercise on bicycle ergometer. After fat load total cholesterol (TC) concentration did not change in either group. However, after the addition of maximal exercise, TC, triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein (Apo) B increased significantly (P < .01) in both groups. After fat load and maximal exercise, there was no change in high-density lipoprotein cholesterol (HDL-C) in healthy men, but in men with CHD, HDL-C fell significantly (P < .01); and Apo AI rose in healthy men (P < .01) but dropped significantly (P < .01) in men with CHD. Submaximal physical exercise (60% of max VO2 load for 40 minutes) after fat load decreased TG level in CHD patients (P < .01) and improved other lipid parameters in both groups significantly (↓LDL-C, ↑HDL-C, ↑Apo AI, ↓Apo B, P < .01). We observed a worsening of physical work capacity in men with CHD (significant reduction of duration and total amount of work performed, maximal VO2, oxygen pulse), during maximal stress test performed 3 hours after fat load. There was a doubling of the number of abnormal stress test results (P < .01). Healthy persons showed an increase in respiratory parameters (ventilation, CO2 production, maximal VO2, and oxygen

  12. Reliability and Seasonal Changes of Submaximal Variables to Evaluate Professional Cyclists.

    Science.gov (United States)

    Rodríguez-Marroyo, Jose A; Pernía, Raúl; Villa, José G; Foster, Carl

    2017-11-01

    The aim of this study was to determine the reliability and validity of several submaximal variables that can be easily obtained by monitoring cyclists' performances. Eighteen professional cyclists participated in this study. In a first part (n = 15) the test-retest reliability of heart rate (HR) and rating of perceived exertion (RPE) during a progressive maximal test was measured. Derived submaximal variables based on HR, RPE, and power output (PO) responses were analyzed. In a second part (n = 7) the pattern of the submaximal variables according to cyclists' training status was analyzed. Cyclists were assessed 3 times during the season: at the beginning of the season, before the Vuelta a España, and the day after this Grand Tour. Part 1: No significant differences in maximal and submaximal variables between test-retest were found. Excellent ICCs (0.81-0.98) were obtained in all variables. Part 2: The HR and RPE showed a rightward shift from early to peak season. In addition, RPE showed a left shift after the Vuelta a España. Submaximal variables based on RPE had the best relationship with both performance and changes in performance. The present study showed the reliability of different maximal and submaximal variables used to assess cyclists' performances. Submaximal variables based on RPE seem to be the best to monitor changes in training status over a season.

  13. COMPARISON OF ROWING ON A CONCEPT 2 STATIONARY AND DYNAMIC ERGOMETER

    Directory of Open Access Journals (Sweden)

    Aaron Benson

    2011-06-01

    Full Text Available Biomechanical and physiological responses to rowing 1000 m at a power output equivalent to a 2000 m race were compared in 34 collegiate rowers (17 women, 17 men rowing on a stationary and dynamic Concept 2 ergometer. Stroke ratio, peak handle force, rate of force development, impulse, and respiratory exchange ratio decreased by 15.7, 14.8, 10.9, 10.2 and 1.9%, respectively, on the dynamic ergometer. In contrast, percent time to peak force and stroke rate increased by 10.5 and 12.6%, respectively, during dynamic ergometry; the changes in stroke rate and impulse were greater for men than women. Last, VO2 was 5.1% higher and efficiency 5. 3% lower on the dynamic ergometer for men. Collegiate rowers used higher stoke rates and lower peak stroke forces to achieve a similar power output while rowing at race pace on the dynamic ergometer, which may have increased the cardiopulmonary demand and possibly reduced force production in the primary movers. Differences were more pronounced in males than females; this dichotomy may be more due to dynamic ergometer familiarity than sex

  14. Muscle Synergies of Untrained Subjects during 6 min Maximal Rowing on Slides and Fixed Ergometer

    Directory of Open Access Journals (Sweden)

    Shazlin Shaharudin

    2014-12-01

    Full Text Available The slides ergometer (SE was an improvisation from fixed ergometer (FE to bridge the gap of mechanics between ergometer rowing and on-water rowing. The specific mechanical constraints of these two types of ergometers may affect the pattern of muscle recruitment, coordination and adaptation. The main purpose of this study was to evaluate the muscle synergy during 6 minutes maximal rowing on slides (SE and fixed ergometers (FE. The laterality of muscle synergy was also examined. Surface electromyography activity, power output, heart rate, stroke length and stroke rate were analyzed from nine physically active subjects to assess the rowing performance. Physically active subjects, who were not specifically trained in rowing, were chosen to exclude the training effect on muscle synergy. Principal component analysis (PCA with varimax rotation was applied to extract muscle synergy. Three muscle synergies were sufficient to explain the majority of variance in SE (94.4 ± 2.2 % and FE (92.8 ± 1.7 %. Subjects covered more rowing distance, exerted greater power output and attained higher maximal heart rate during rowing on SE than on FE. The results proved the flexibility of muscle synergy to adapt to the mechanical constraints. Rowing on SE emphasized on bi-articular muscles contrary to rowing on FE which relied on cumulative effect of trunk and upper limb muscles during propulsive phase.

  15. Underwater Cycle Ergometry: Power Requirements With and Without Diver Thermal Dress

    National Research Council Canada - National Science Library

    Shykoff, B

    2009-01-01

    .... An ongoing problem has been that, although the power requirement of cycling in the water is known to be greater than that in air for the same ergometer setting, the magnitude of the difference...

  16. Relationship between the Pedaling Biomechanics and Strain of Bicycle Frame during Submaximal Tests

    Directory of Open Access Journals (Sweden)

    Aneliya V. Manolova

    2015-06-01

    Full Text Available The aim of this study was to analyse the effect of forces applied to pedals and cranks on the strain imposed to an instrumented bicycle motocross (BMX frame. Using results from a finite element analysis to determine the localisation of highest stress, eight strain gauges were located on the down tube, the seat tube and the right chain stay. Before the pedaling tests, static loads were applied to the frame during bench tests. Two pedaling conditions have been analysed. In the first, the rider was in static standing position on the pedals and applied maximal muscular isometric force to the right pedal. The second pedaling condition corresponds to three pedaling sprint tests at submaximal intensities at 150, 300 and 550 W on a cycle-trainer. The results showed that smaller strain was observed in the pedaling condition than in the rider static standing position condition. The highest strains were located in the seat tube and the right chain stay near the bottom bracket area. The maximum stress observed through all conditions was 41 MPa on the right chain stay. This stress was 11 times lower than the yield stress of the frame material (460 MPa. This protocol could help to adapt the frame design to the riders as a function of their force and mechanical power output. These results could also help design BMX frames for specific populations (females and rider morphology.

  17. Ramadan fasting and the GH/IGF-1 axis of trained men during submaximal exercise.

    Science.gov (United States)

    Bouhlel, Ezzedine; Zaouali, Monia; Miled, Abdelhedi; Tabka, Zouhair; Bigard, Xavier; Shephard, Roy

    2008-01-01

    The aim of this study was to explore possible changes in body composition, blood glucose regulation, plasma growth hormone (GH), insulin-like growth factor 1 (IGF-1), insulin-like growth factor-binding protein-3 (IGFBP-3), and insulin concentrations of trained athletes in response to the intermittent fasting and dehydration of Ramadan observance. Nine trained male rugby players (age 19 +/- 2 years, height 1.78 +/- 0.74 m) were tested 3 times: before Ramadan (C), at the end of the first week (R1), and during the fourth week (R2). They performed a progressive cycle ergometer test at each visit. The work rate was increased in 6-min stages corresponding to 20, 30, 40, 50 and 60% of W max. Substrate oxidation was evaluated by indirect calorimetry. On each occasion, substrate and plasma hormone concentrations were measured at rest and at the end of the exercise. Ramadan fasting induced a significant decrease in body mass and body fat (R2 vs. C, p < 0.001). Plasma concentrations of glucose, insulin, GH, IGF-1 and IGFBP-3 did not change significantly between C and R2, either at rest or following exercise. Ramadan fasting induces positive changes in body composition without disturbing glucose regulation or activity of the GH/IGF-1 system. 2008 S. Karger AG, Basel.

  18. Acclimatization improves submaximal exercise economy at 5533 m.

    Science.gov (United States)

    Latshang, T D; Turk, A J; Hess, T; Schoch, O D; Bosch, M M; Barthelmes, D; Merz, T M; Hefti, U; Hefti, J Pichler; Maggiorini, M; Bloch, K E

    2013-08-01

    We tested whether the better subjective exercise tolerance perceived by mountaineers after altitude acclimatization relates to enhanced exercise economy. Thirty-two mountaineers performed progressive bicycle exercise to exhaustion at 490 m and twice at 5533 m (days 6-7 and day 11), respectively, during an expedition to Mt. Muztagh Ata. Maximal work rate (W(max)) decreased from mean ± SD 356 ± 73 watts at 490 m to 191 ± 49 watts and 193 ± 45 watts at 5533 m, days 6-7 and day 11, respectively; corresponding maximal oxygen uptakes (VO2max ) were 50.7 ± 9.5, 26.3 ± 5.6, 24.7 ± 7.0 mL/min/kg (P = 0.0001 5533 m vs 490 m). On days 6-7 (5533 m), VO(2) at 75% W(max) (152 ± 37 watts) was 1.75 ± 0.45 L/min, oxygen saturation 68 ± 8%. On day 11 (5533 m), at the same submaximal work rate, VO(2) was lower (1.61 ± 0.47 L/min, P scale 50 ± 15 vs 57 ± 20, P = 0.006) and reduced symptoms of acute mountain sickness. We conclude that the better performance and subjective exercise tolerance after acclimatization were related to regression of acute mountain sickness and improved submaximal exercise economy because of lower metabolic demands for non-external work-performing functions. © 2011 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Muscle Synergies of Untrained Subjects during 6 min Maximal Rowing on Slides and Fixed Ergometer.

    Science.gov (United States)

    Shaharudin, Shazlin; Zanotto, Damiano; Agrawal, Sunil

    2014-12-01

    The slides ergometer (SE) was an improvisation from fixed ergometer (FE) to bridge the gap of mechanics between ergometer rowing and on-water rowing. The specific mechanical constraints of these two types of ergometers may affect the pattern of muscle recruitment, coordination and adaptation. The main purpose of this study was to evaluate the muscle synergy during 6 minutes maximal rowing on slides (SE) and fixed ergometers (FE). The laterality of muscle synergy was also examined. Surface electromyography activity, power output, heart rate, stroke length and stroke rate were analyzed from nine physically active subjects to assess the rowing performance. Physically active subjects, who were not specifically trained in rowing, were chosen to exclude the training effect on muscle synergy. Principal component analysis (PCA) with varimax rotation was applied to extract muscle synergy. Three muscle synergies were sufficient to explain the majority of variance in SE (94.4 ± 2.2 %) and FE (92.8 ± 1.7 %). Subjects covered more rowing distance, exerted greater power output and attained higher maximal heart rate during rowing on SE than on FE. The results proved the flexibility of muscle synergy to adapt to the mechanical constraints. Rowing on SE emphasized on bi-articular muscles contrary to rowing on FE which relied on cumulative effect of trunk and upper limb muscles during propulsive phase. Key pointsThree muscle synergies were extracted during maximal rowing on both fixed and slides ergometerUntrained subjects emphasized leg muscles while rowing on SEUntrained subjects focused on back muscles during FE rowing.

  20. Neuromuscular function of the quadriceps muscle during isometric maximal, submaximal and submaximal fatiguing voluntary contractions in knee osteoarthrosis patients.

    Directory of Open Access Journals (Sweden)

    Anett Mau-Moeller

    and neuromuscular activation, but also with an impaired position and torque control at submaximal torque levels, an altered EMG-torque relationship and a higher performance fatigability of the quadriceps muscle. It is recommended that the rehabilitation includes strengthening and fatiguing exercises at maximal and submaximal force levels.

  1. Effects of ethnicity on the relationship between vertical jump and maximal power on a cycle ergometer.

    Science.gov (United States)

    Rouis, Majdi; Coudrat, Laure; Jaafar, Hamdi; Attiogbé, Elvis; Vandewalle, Henry; Driss, Tarak

    2016-06-01

    The aim of this study was to verify the impact of ethnicity on the maximal power-vertical jump relationship. Thirty-one healthy males, sixteen Caucasian (age: 26.3 ± 3.5 years; body height: 179.1 ± 5.5 cm; body mass: 78.1 ± 9.8 kg) and fifteen Afro-Caribbean (age: 24.4 ±2.6 years; body height: 178.9 ± 5.5 cm; body mass: 77.1 ± 10.3 kg) completed three sessions during which vertical jump height and maximal power of lower limbs were measured. The results showed that the values of vertical jump height and maximal power were higher for Afro-Caribbean participants (62.92 ± 6.7 cm and 14.70 ± 1.75 W∙kg-1) than for Caucasian ones (52.92 ± 4.4 cm and 12.75 ± 1.36 W∙kg-1). Moreover, very high reliability indices were obtained on vertical jump (e.g. 0.95 jumped 8 cm higher than the Caucasians. Together, these results confirmed that ethnicity impacted the maximal power-vertical jump relationship over three sessions. In the current context of cultural diversity, the use of vertical jump performance as a predictor of muscular power should be considered with caution when dealing with populations of different ethnic origins.

  2. Effects of ethnicity on the relationship between vertical jump and maximal power on a cycle ergometer

    Directory of Open Access Journals (Sweden)

    Rouis Majdi

    2016-06-01

    Full Text Available The aim of this study was to verify the impact of ethnicity on the maximal power-vertical jump relationship. Thirty-one healthy males, sixteen Caucasian (age: 26.3 ± 3.5 years; body height: 179.1 ± 5.5 cm; body mass: 78.1 ± 9.8 kg and fifteen Afro-Caribbean (age: 24.4 ±2.6 years; body height: 178.9 ± 5.5 cm; body mass: 77.1 ± 10.3 kg completed three sessions during which vertical jump height and maximal power of lower limbs were measured. The results showed that the values of vertical jump height and maximal power were higher for Afro-Caribbean participants (62.92 ± 6.7 cm and 14.70 ± 1.75 W∙kg-1 than for Caucasian ones (52.92 ± 4.4 cm and 12.75 ± 1.36 W∙kg-1. Moreover, very high reliability indices were obtained on vertical jump (e.g. 0.95 < ICC < 0.98 and maximal power performance (e.g. 0.75 < ICC < 0.97. However, multiple linear regression analysis showed that, for a given value of maximal power, the Afro-Caribbean participants jumped 8 cm higher than the Caucasians. Together, these results confirmed that ethnicity impacted the maximal power-vertical jump relationship over three sessions. In the current context of cultural diversity, the use of vertical jump performance as a predictor of muscular power should be considered with caution when dealing with populations of different ethnic origins.

  3. Prediction of performance in Vasaloppet through long lasting ski- ergometer and rollerski tests in cross-country skiers

    DEFF Research Database (Denmark)

    Mygind, Erik; Wulff, Kristian; Jensen, Mads Rosenkilde

    2015-01-01

    and completed Vasaloppet. All skiers carried out pre and post training tests in a 90 minutes ski-ergometer double poling test and a 120 minutes rollerski field test on a closed paved circuit. 19 skiers provided detailed training logs that could sufficiently establish their training preparation for Vasaloppet....... Racing time in Vasaloppet correlated negatively with average work output (W/kg) at the pre ski-ergometer test (Figure 3A) (n = 24; r = -0.79; P ski performance was positively associated with ergometer performance. Likewise, a similar correlation was obtained after the 16 week training...... period between average post-test work output in the ski-ergometer and performance in Vasaloppet (n = 24; r = -0.76; P ski-ergometer tests. Pre-field-test time performance on rollerskies as measured...

  4. (Originals) Anthropometric and Physiological Factors Predicting 2000 m Rowing Ergometer Performance Time

    OpenAIRE

    Chie, Yoshiga; Yasuo, Kawakami; Tetsuo, Fukunaga; Graduate School of Education,The University of Tokyo; Graduate School of Arts and Science,The University of Tokyo; Graduate School of Arts and Science,The University of Tokyo

    2000-01-01

    In attempt to predict 2000 m rowing ergometer performance time, we studied anthropometric and physiological limiting factors among 78 collegiate male rowers. Among variables that we measured, 2000 m rowing performance time was significantly and inversely related to lean body mass(r=-0.68), maximal oxygen uptake(-0.64), and leg extension power(-0.54)(p

  5. Anthropometric determinants of rowing ergometer performance in physically inactive collegiate females.

    Science.gov (United States)

    Podstawski, R; Choszcz, Dj; Konopka, S; Klimczak, J; Starczewski, M

    2014-12-01

    The aim of the study was to evaluate anthropometric characteristics as determinants of 500 m rowing ergometer performance in physically inactive collegiate females. In this cross-sectional study, which included 196 collegiate females aged 19-23 years not participating in regular physical activities, body mass (BM), body height (BH), length of upper limbs (LA), length of lower limbs (LL), body mass index (BMI), slenderness index (SI), and the Choszcz-Podstawski index (CPI) were measured and a stepwise multiple regression analysis was performed. Participants performed 500 m maximal effort on a Concept II rowing ergometer. BM, BH, LA, LL, and the BMI, SI and CPI indices were found to be statistically significant determinants of 500 m performance. The best results (T) were achieved by females whose BH ranged from 170 to 180 cm, with LA and LL ranging from 75 to 80 cm and 85 to 90 cm, respectively. The best fitting statistical model was identified as: T = 11.6793 LR - 0.1130 LR (2) - 0.0589 LN (2) + 29.2157 CPI(2) + 0.1370 LR·LN - 2.6926 LR·CPI - 211.7796. This study supports a need for additional studies focusing on understanding the importance of anthropometric differences in rowing ergometer performance, which could lead to establishing a better quality reference for evaluation of cardiorespiratory fitness tested using a rowing ergometer in collegiate females.

  6. Pink noise in rowing ergometer performance and the role of skill level

    NARCIS (Netherlands)

    Den Hartigh, Ruud J.R.; Cox, Ralf F.A.; Gernigon, Christophe; Van Yperen, Nico W.; Van Geert, Paul L.C.

    2015-01-01

    The aim of this study was to examine (1) the temporal structures of variation in rowers' (natural) ergometer strokes in order to make inferences about the underlying motor organization, and (2) the relation between these temporal structures and skill level. Four high-skilled and five lower-skilled

  7. Assessment of cardiorespiratory fitness using submaximal protocol in older adults with mood disorder and Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Natacha Alves de Oliveira

    2013-01-01

    Full Text Available BACKGROUND: Evidence has shown benefits for mental health through aerobic training oriented in percentage of VO2max, indicating the importance of this variable for clinical practice. OBJECTIVE: To validate a method for estimating VO2max using a submaximal protocol in elderly patients with clinically diagnosis as major depressive disorder (MDD and Parkinson's disease (PD. METHODS: The sample comprised 18 patients (64.22 ± 9.92 years with MDD (n = 7 and with PD (n = 11. Three evaluations were performed: I disease staging, II direct measurement of VO2max and III submaximal exercise test. Linear regression was performed to verify the accuracy of estimation in VO2max established in ergospirometry and the predicted VO2max from the submaximal test measurement. We also analyzed the correlation between the Bland-Altman procedures. RESULTS: The regression analysis showed that VO2max values estimated by submaximal protocol associated with the VO2max measured, both in absolute values (R² = 0.65; SEE = 0.26; p < 0.001 and the relative (R² = 0.56; SEE = 3.70; p < 0.001. The Bland-Altman plots for analysis of agreement of showed a good correlation between the two measures. DISCUSSION: The VO2max predicted by submaximal protocol demonstrated satisfactory criterion validity and simple execution compared to ergospirometry.

  8. Sports biomechanics in the research of the Department of Biomechanics of University School of Physical Education in Poznań. Part 1. Biomechanics of rowing: tests on rowing ergometers, reconstruction and synthesis.

    Science.gov (United States)

    Dworak, Lechosław B

    2010-01-01

    The purpose of this study is to reconstruct the early phase of scientific research conducted at the Department of Biomechanics of the University School of Physical Education in Poznan, particularly the work on biomechanics of rowing, conducted as part of the Ministerial Project PR 105, entitled "The effectiveness of training and competition as well as regeneration in sports". Three kinds of research have been described, carried out with the use of the rowing ergometers. The first was the research on neuromuscular coordination in the rowing cycle, the second was the research on kinematic and dynamic characteristics of rowing on the Universal Rowing Ergometer UEW - 1, while the last one concerned determination of maximum forces generated by functional muscle groups in two characteristic rowing positions within the closed biochain of the torso and the limbs.

  9. Scaling concept II rowing ergometer performance for differences in body mass to better reflect rowing in water.

    Science.gov (United States)

    Nevill, A M; Beech, C; Holder, R L; Wyon, M

    2010-02-01

    We investigated whether the concept II indoor rowing ergometer accurately reflects rowing on water. Forty-nine junior elite male rowers from a Great Britain training camp completed a 2000 m concept II model C indoor rowing ergometer test and a water-based 2000 m single-scull rowing test. Rowing speed in water (3.66 m/s) was significantly slower than laboratory-based rowing performance (4.96 m/s). The relationship between the two rowing performances was found to be R2=28.9% (r=0.538). We identified that body mass (m) made a positive contribution to concept II rowing ergometer performance (r=0.68, Prowing performance (r=0.039, P=0.79). The contribution that m made to single-scull rowing in addition to ergometer rowing speed (using allometric modeling) was found to be negative (Prowing speed. The optimal allometric model to predict single-scull rowing speed was the ratio (ergometer speed xm(-0.23))1.87 that increased R2 from 28.2% to 59.2%. Simply by dividing the concept II rowing ergometer speed by body mass (m0.23), the resulting "power-to-weight" ratio (ergometer speed xm(-0.23)) improves the ability of the concept II rowing performance to reflect rowing on water.

  10. THE INFLUENCE OF OBESITY AND AMBIENT TEMPERATURE ON PHYSIOLOGICAL AND OXIDATIVE RESPONSES TO SUBMAXIMAL EXERCISE

    OpenAIRE

    Ahn, N.; Kim, K.

    2014-01-01

    This study investigated the effects of obesity and ambient temperature on physiological responses and markers of oxidative stress to submaximal exercise in obese and lean people. Sixteen healthy males were divided into an obese group (n=8, %fat: 27.00±3.00%) and a lean group (n=8, %fat: 13.85±2.45%). Study variables were measured during a 60 min submaximal exercise test at 60% VO2max in a neutral (21±1°C) and a cold (4±1°C) environment. Heart rate, blood lactate, rectal temperature, serum lev...

  11. Factors of Rowing Ergometer Performance in High-Level Female Rowers.

    Science.gov (United States)

    Bourdin, Muriel; Lacour, Jean-Rene; Imbert, Charles; Messonnier, Laurent André

    2017-11-01

    The present study investigated morphological and physiological factors of rowing ergometer performance over 2000 m (P2000, W) in 70 national and international level [27 lightweight (LW) and 43 heavyweight (HW)] female rowers. Maximal oxygen uptake (V̇O2max, L.min-1), maximal aerobic power (Pamax, W), power output corresponding to 4 mmol.L-1 blood lactate concentration expressed in absolute (PLa4, W) and relative to Pamax (PLa4%, %) values, peak power output (Ppeak, W), and rowing gross efficiency (RGE, %) were determined during an incremental rowing test. In the whole group, Ppeak was the best predictor of P2000 (r=0.89, prowing capacity in groups of high-level LW and HW female rowers. The predictive value of Ppeak is similar to that of PLa4, but Ppeak presents the advantage of being obtained with a simple ergometer test without biological measurements. © Georg Thieme Verlag KG Stuttgart · New York.

  12. Submaximal arm crank ergometry : Effects of crank axis positioning on mechanical efficiency, physiological strain and perceived discomfort

    NARCIS (Netherlands)

    van Drongelen, S; Maas, J C; Scheel-Sailer, A; Van Der Woude, L H V

    2009-01-01

    PURPOSE: To evaluate the effect of the spatial orientation of the crank axis on mechanical efficiency, physiological strain and perceived discomfort in submaximal synchronous arm crank ergometry. METHODS: Twelve able-bodied individuals performed 12 submaximal exercise bouts of 3 minutes (women: 20

  13. Shoulder muscle strength in paraplegics before and after kayak ergometer training.

    Science.gov (United States)

    Bjerkefors, Anna; Jansson, Anna; Thorstensson, Alf

    2006-07-01

    The purpose was to investigate if shoulder muscle strength in post-rehabilitated persons with spinal cord injury (SCI) was affected by kayak ergometer training and to compare shoulder strength in persons with SCI and able-bodied persons. Ten persons with SCI (7 males and 3 females, injury levels T3-T12) performed 60 min kayak ergometer training three times a week for 10 weeks with progressively increased intensity. Maximal voluntary concentric contractions were performed during six shoulder movements: flexion and extension (range of motion 65 degrees ), abduction and adduction (65 degrees ), and external and internal rotation (60 degrees ), with an angular velocity of 30 degrees s(-1). Position specific strength was assessed at three shoulder angles (at the beginning, middle and end of the range of motion) in the respective movements. Test-retests were performed for all measurements before the training and the mean intraclass correlation coefficient was 0.941 (95% CI 0.928-0.954). There was a main effect of kayak ergometer training with increased shoulder muscle strength after training in persons with SCI. The improvements were independent of shoulder movement, and occurred in the beginning and middle positions. A tendency towards lower shoulder muscle strength was observed in the SCI group compared to a matched reference group of able-bodied persons. Thus, it appears that post-rehabilitated persons with SCI have not managed to fully regain/maintain their shoulder muscle strength on a similar level as that of able-bodied persons, and are able to improve their shoulder muscle strength after a period of kayak ergometer training.

  14. Peak Power Output Test on a Rowing Ergometer: A Methodological Study.

    Science.gov (United States)

    Metikos, Boris; Mikulic, Pavle; Sarabon, Nejc; Markovic, Goran

    2015-10-01

    We aimed to examine the reliability and validity of the peak power output test on a rowing ergometer (Concept II Model D Inc.) and to establish the "optimal resistance" at which this peak power output was observed in 87 participants with varying levels of physical activity and rowing expertise: 15 male and 12 female physically inactive students (age: 21 ± 2 years), 16 male and 20 female physically active students (age: 23 ± 2 years), and 15 male and 9 female trained rowers (age: 19 ± 2 years). The participants performed countermovement jump (CMJ) test on a force plate, followed by 3 maximal-effort rowing trials using the lowest, medium, and the highest adjustable resistance settings (i.e., "1", "5," and "10" on the resistance control dial on the ergometer) in randomized order. The test proved to be reliable (coefficients of variation: 2.6-6.5%; intraclass correlation coefficients: 0.87-0.98). The correlation coefficients between CMJ peak power and rowing peak power (both in watts per kilogram) were fairly consistent across all 3 groups of participants and resistance levels, ranging between r = 0.70 and r = 0.78. Finally, the highest power output was observed at the highest resistance setting in 2 nonathletic groups (p rowing ergometer may serve as a reliable and valid tool for assessing whole-body peak power output in untrained individuals and rowing athletes.

  15. Prediction of rowing ergometer performance from functional anaerobic power, strength and anthropometric components.

    Science.gov (United States)

    Akça, Fırat

    2014-06-28

    The aim of this research was to develop different regression models to predict 2000 m rowing ergometer performance with the use of anthropometric, anaerobic and strength variables and to determine how precisely the prediction models constituted by different variables predict performance, when conducted together in the same equation or individually. 38 male collegiate rowers (20.17 ± 1.22 years) participated in this study. Anthropometric, strength, 2000 m maximal rowing ergometer and rowing anaerobic power tests were applied. Multiple linear regression procedures were employed in SPSS 16 to constitute five different regression formulas using a different group of variables. The reliability of the regression models was expressed by R2 and the standard error of estimate (SEE). Relationships of all parameters with performance were investigated through Pearson correlation coefficients. The prediction model using a combination of anaerobic, strength and anthropometric variables was found to be the most reliable equation to predict 2000 m rowing ergometer performance (R2 = 0.92, SEE= 3.11 s). Besides, the equation that used rowing anaerobic and strength test results also provided a reliable prediction (R2 = 0.85, SEE= 4.27 s). As a conclusion, it seems clear that physiological determinants which are affected by anaerobic energy pathways should also get involved in the processes and models used for performance prediction and talent identification in rowing.

  16. Prediction of Rowing Ergometer Performance from Functional Anaerobic Power, Strength and Anthropometric Components

    Directory of Open Access Journals (Sweden)

    Akça Firat

    2014-07-01

    Full Text Available The aim of this research was to develop different regression models to predict 2000 m rowing ergometer performance with the use of anthropometric, anaerobic and strength variables and to determine how precisely the prediction models constituted by different variables predict performance, when conducted together in the same equation or individually. 38 male collegiate rowers (20.17 ± 1.22 years participated in this study. Anthropometric, strength, 2000 m maximal rowing ergometer and rowing anaerobic power tests were applied. Multiple linear regression procedures were employed in SPSS 16 to constitute five different regression formulas using a different group of variables. The reliability of the regression models was expressed by R2 and the standard error of estimate (SEE. Relationships of all parameters with performance were investigated through Pearson correlation coefficients. The prediction model using a combination of anaerobic, strength and anthropometric variables was found to be the most reliable equation to predict 2000 m rowing ergometer performance (R2 = 0.92, SEE= 3.11 s. Besides, the equation that used rowing anaerobic and strength test results also provided a reliable prediction (R2 = 0.85, SEE= 4.27 s. As a conclusion, it seems clear that physiological determinants which are affected by anaerobic energy pathways should also get involved in the processes and models used for performance prediction and talent identification in rowing.

  17. Intensity-dependent EMG response for the biceps brachii during sustained maximal and submaximal isometric contractions.

    Science.gov (United States)

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

    2016-09-01

    There have been recent attempts to characterize the mechanisms associated with fatigue-induced task failure. We compared the time to failure and the corresponding changes in the surface electromyogram (EMG) during sustained maximal and submaximal isometric force tasks. EMG activity was measured from the biceps brachii of 18 male participants as they sustained either a maximal or submaximal (60 % MVC) isometric contraction of the dominant elbow flexors until force could not be maintained above 55 % MVC. Intensity-dependent patterns of change were observed for EMG amplitude and mean power frequency (MNF) between the two force tasks. Interestingly, the only significant predictor of failure time was the rate of change in EMG MNF during the submaximal task (r (2) = 0.304). In addition, EMG amplitude at submaximal failure was significantly lower (p EMG response emphasize the basis of neuromuscular fatigue and task dependency. Additionally, our data suggest that the EMG MNF should be used when monitoring the progression of local muscle fatigue.

  18. Variation in heart rate during submaximal exercise: Implications for monitoring training : Implications for monitoring training

    NARCIS (Netherlands)

    Lamberts, R.P.; Lemmink, K.A.P.M.; Durandt, J.J.; Lambert, M.I.

    2004-01-01

    A change in heart rate at a controlled submaximal exercise intensity is used as a marker of training status. However, the standard error of measurement has not been studied systematically, and therefore a change in heart rate, which can be considered relevant, has not been determined. Forty-four

  19. THE EFFECT OF SUBMAXIMAL INHALATION ON MEASURES DERIVED FROM FORCED EXPIRATORY SPIROMETRY

    Science.gov (United States)

    THE EFFECT OF SUBMAXIMAL INHALATION ON MEASURES DERIVED FROM FORCED EXPIRATORY SPIROMETRY. William F. McDonnell Human Studies Division, NHEERL, U.S. Environmental Protection Agency, RTP, NC 27711. Short-term exposure to ozone results in a neurally-mediated decrease in the ab...

  20. Calibration of EMG to force for knee muscles is applicable with submaximal voluntary contractions

    NARCIS (Netherlands)

    Doorenbosch, C.A.M.; Joosten, A.; Harlaar, J.

    2005-01-01

    Purpose: In this study, the influence of using submaximal isokinetic contractions about the knee compared to maximal voluntary contractions as input to obtain the calibration of an EMG-force model for knee muscles is investigated. Methods: Isokinetic knee flexion and extension contractions were

  1. Is an elevated submaximal heart rate associated with psychomotor slowness in young elite soccer players?

    NARCIS (Netherlands)

    Brink, Michel S.; Visscher, Chris; Schmikli, Sandor L.; Nederhof, E.; Lemmink, Koen A. P. M.

    2013-01-01

    The aim of the present study was to find early markers for overreaching that are applicable in sport practice. In a group of elite soccer players aged 1518, the stressrecovery balance and reaction times before and after exercise were assessed. Overreaching was indicated by an elevated submaximal

  2. Systolic blood pressure reactivity during submaximal exercise and acute psychological stress in youth

    Science.gov (United States)

    Background: Studies in youth show an association between systolic blood-pressure (SBP) reactivity to acute psychological stress and carotid artery intima-media thickness (CIMT). However, it has not yet been determined whether SBP reactivity during submaximal exercise is also associated with CIMT i...

  3. Effects of 16-week high-intensity interval training using upper and lower body ergometers on aerobic fitness and morphological changes in healthy men: a preliminary study

    Directory of Open Access Journals (Sweden)

    Osawa Y

    2014-11-01

    Full Text Available Yusuke Osawa,1,2,* Koichiro Azuma,3,* Shogo Tabata,3 Fuminori Katsukawa,2 Hiroyuki Ishida,2 Yuko Oguma,2 Toshihide Kawai,4 Hiroshi Itoh,4 Shigeo Okuda,5 Hideo Matsumoto3 1Japan Society for the Promotion of Science, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan; 2Sports Medicine Research Center, Keio University, Kanagawa, Japan; 3Institute for Integrated Sports Medicine, School of Medicine, Keio University, Tokyo, Japan; 4Department of Internal Medicine, School of Medicine, Keio University, Tokyo, Japan; 5Department of Radiology, School of Medicine, Keio University, Tokyo, Japan *Yusuke Osawa and Koichiro Azuma are co-first authors of this article Abstract: It is unclear whether combined leg and arm high-intensity interval training (HIIT improves fitness and morphological characteristics equal to those of leg-based HIIT programs. The aim of this study was to compare the effects of HIIT using leg-cycling (LC and arm-cranking (AC ergometers with an HIIT program using only LC. Effects on aerobic capacity and skeletal muscle were analyzed. Twelve healthy male subjects were assigned into two groups. One performed LC-HIIT (n=7 and the other LC- and AC-HIIT (n=5 twice weekly for 16 weeks. The training programs consisted of eight to 12 sets of >90% VO2 (the oxygen uptake that can be utilized in one minute peak for 60 seconds with a 60-second active rest period. VO2 peak, watt peak, and heart rate were measured during an LC incremental exercise test. The cross-sectional area (CSA of trunk and thigh muscles as well as bone-free lean body mass were measured using magnetic resonance imaging and dual-energy X-ray absorptiometry. The watt peak increased from baseline in both the LC (23%±38%; P<0.05 and the LC–AC groups (11%±9%; P<0.05. The CSA of the quadriceps femoris muscles also increased from baseline in both the LC (11%±4%; P<0.05 and the LC–AC groups (5%±5%; P<0.05. In contrast, increases were observed in the CSA of

  4. Eight weeks of intermittent hypoxic training improves submaximal physiological variables in highly trained runners.

    Science.gov (United States)

    Holliss, Ben A; Burden, Richard J; Jones, Andrew M; Pedlar, Charles R

    2014-08-01

    It is unclear whether intermittent hypoxic training (IHT) results in improvements in physiological variables associated with endurance running. Twelve highly trained runners (VO2peak 70.0 ± 3.5 ml·kg-1·min-1) performed incremental treadmill tests to exhaustion in normobaric normoxia and hypoxia (16.0% FIO2) to assess submaximal and maximal physiological variables and the limit of tolerance (T-Lim). Participants then completed 8 weeks of moderate to heavy intensity normoxic training (control [CONT]) or IHT (twice weekly 40 minutes runs, in combination with habitual training), in a single blinded manner, before repeating the treadmill tests. Submaximal heart rate decreased significantly more after IHT (-5 ± 5 b·min-1; p = 0.001) than after CONT ( -1 ± 5 b·min-1; p = 0.021). Changes in submaximal V[Combining Dot Above]O2 were significantly different between groups (p ≤ 0.05); decreasing in the IHT group in hypoxia (-2.6 ± 1.7 ml·kg-1·min-1; p = 0.001) and increasing in the CONT group in normoxia (+1.1 ± 2.1 ml·kg-1·min-1; p = 0.012). There were no VO2peak changes within either group, and while T-Lim improved post-IHT in hypoxia (p = 0.031), there were no significant differences between groups. Intermittent hypoxic training resulted in a degree of enhanced cardiovascular fitness that was evident during submaximal, but not maximal intensity exercise. These results suggest that moderate to heavy intensity IHT provides a mean of improving the capacity for submaximal exercise and may be useful for pre-acclimatization for subsequent exercise in hypoxia, but additional research is required to establish its efficacy for athletic performance at sea level.

  5. Effects of a helium/oxygen mixture on individuals' lung function and metabolic cost during submaximal exercise for participants with obstructive lung diseases.

    Science.gov (United States)

    Häussermann, Sabine; Schulze, Anja; Katz, Ira M; Martin, Andrew R; Herpich, Christiane; Hunger, Theresa; Texereau, Joëlle

    2015-01-01

    Helium/oxygen therapies have been studied as a means to reduce the symptoms of obstructive lung diseases with inconclusive results in clinical trials. To better understand this variability in results, an exploratory physiological study was performed comparing the effects of helium/oxygen mixture (78%/22%) to that of medical air. The gas mixtures were administered to healthy, asthmatic, and chronic obstructive pulmonary disease (COPD) participants, both moderate and severe (6 participants in each disease group, a total of 30); at rest and during submaximal cycling exercise with equivalent work rates. Measurements of ventilatory parameters, forced spirometry, and ergospirometry were obtained. There was no statistical difference in ventilatory and cardiac responses to breathing helium/oxygen during submaximal exercise. For asthmatics, but not for the COPD participants, there was a statistically significant benefit in reduced metabolic cost, determined through measurement of oxygen uptake, for the same exercise work rate. However, the individual data show that there were a mixture of responders and nonresponders to helium/oxygen in all of the groups. The inconsistent response to helium/oxygen between individuals is perhaps the key drawback to the more effective and widespread use of helium/oxygen to increase exercise capacity and for other therapeutic applications.

  6. Effects of a helium/oxygen mixture on individuals’ lung function and metabolic cost during submaximal exercise for participants with obstructive lung diseases

    Science.gov (United States)

    Häussermann, Sabine; Schulze, Anja; Katz, Ira M; Martin, Andrew R; Herpich, Christiane; Hunger, Theresa; Texereau, Joëlle

    2015-01-01

    Background Helium/oxygen therapies have been studied as a means to reduce the symptoms of obstructive lung diseases with inconclusive results in clinical trials. To better understand this variability in results, an exploratory physiological study was performed comparing the effects of helium/oxygen mixture (78%/22%) to that of medical air. Methods The gas mixtures were administered to healthy, asthmatic, and chronic obstructive pulmonary disease (COPD) participants, both moderate and severe (6 participants in each disease group, a total of 30); at rest and during submaximal cycling exercise with equivalent work rates. Measurements of ventilatory parameters, forced spirometry, and ergospirometry were obtained. Results There was no statistical difference in ventilatory and cardiac responses to breathing helium/oxygen during submaximal exercise. For asthmatics, but not for the COPD participants, there was a statistically significant benefit in reduced metabolic cost, determined through measurement of oxygen uptake, for the same exercise work rate. However, the individual data show that there were a mixture of responders and nonresponders to helium/oxygen in all of the groups. Conclusion The inconsistent response to helium/oxygen between individuals is perhaps the key drawback to the more effective and widespread use of helium/oxygen to increase exercise capacity and for other therapeutic applications. PMID:26451096

  7. Gender differences in substrate utilization during submaximal exercise in endurance-trained subjects.

    Science.gov (United States)

    Roepstorff, Carsten; Steffensen, Charlotte H; Madsen, Marianne; Stallknecht, Bente; Kanstrup, Inge-Lis; Richter, Erik A; Kiens, Bente

    2002-02-01

    Substrate utilization across the leg during 90 min of bicycle exercise at 58% of peak oxygen uptake (VO(2 peak)) was studied in seven endurance-trained males and seven endurance-trained, eumenorrheic females by applying arteriovenous catheterization, stable isotopes, and muscle biopsies. The female and male groups were matched according to VO(2 peak) per kilogram of lean body mass, physical activity level, and training history of the subjects. All subjects consumed the same diet, well controlled in terms of nutrient composition as well as energy content, for 8 days preceding the experiment, and all females were tested in the midfollicular phase of the menstrual cycle. During exercise, respiratory exchange ratio (RER) and leg respiratory quotient (RQ) were similar in females and males. Myocellular triacylglycerol (TG) degradation was negligible in males but amounted to 12.4 +/- 3.2 mmol/kg dry wt in females and corresponded to 25.0 +/- 6.0 and 5.0 +/- 7.3% of total oxygen uptake in females and males, respectively (P < 0.05). Utilization of plasma fatty acids (12.0 +/- 2.5 and 9.6 +/- 1.5%), blood glucose (13.6 +/- 1.5 and 14.3 +/- 1.5%), and glycogen (48.5 +/- 4.9 and 42.8 +/- 2.1%) were similar in females and males. Thus, in females, measured substrate oxidation accounted for 99% of the leg oxygen uptake, whereas in males 28% of leg oxygen uptake was unaccounted for in terms of measured oxidized lipid substrates. These findings may indicate that males utilized additional lipid sources, presumably very low density lipoprotein-TG or TG located between muscle fibers. On the basis of RER and leg RQ, it is concluded that no gender difference existed in the relative contribution from carbohydrate and lipids to the oxidative metabolism across the leg during submaximal exercise at the same relative workload. However, an effect of gender appears to occur in the utilization of the different lipid sources.

  8. Normobaric Hypoxia and Submaximal Exercise Effects on Running Memory and Mood State in Women.

    Science.gov (United States)

    Seo, Yongsuk; Gerhart, Hayden D; Stavres, Jon; Fennell, Curtis; Draper, Shane; Glickman, Ellen L

    2017-07-01

    An acute bout of exercise can improve cognitive function in normoxic and hypoxic conditions. However, limited research supports the improvement of cognitive function and mood state in women. The purpose of this study was to examine the effects of hypoxia and exercise on working memory and mood state in women. There were 15 healthy women (age = 22 ± 2 yr) who completed the Automated Neuropsychological Assessment Metrics-4th Edition (ANAM), including the Running Memory Continuous Performance Task (RMCPT) and Total Mood Disturbance (TMD) in normoxia (21% O2), at rest in normoxia and hypoxia (12.5% O2), and during cycling exercise at 60% and 40% Vo2max in hypoxia. RMCPT was not significantly impaired at 30 (100.3 ± 17.2) and 60 (96.6 ± 17.3) min rest in hypoxia compared to baseline in normoxia (97.0 ± 17.0). However, RMCPT was significantly improved during exercise (106.7 ± 20.8) at 60% Vo2max compared to 60 min rest in hypoxia. Following 30 (-89.4 ± 48.3) and 60 min of exposure to hypoxia (-79.8 ± 55.9) at rest, TMD was impaired compared with baseline (-107.1 ± 46.2). TMD was significantly improved during exercise (-108.5 ± 42.7) at 40% Vo2max compared with 30 min rest in hypoxia. Also, RMCPT was significantly improved during exercise (104.0 ± 19.1) at 60% Vo2max compared to 60 min rest in hypoxia (96.6 ± 17.3). Hypoxia and an acute bout of exercise partially influence RMCPT and TMD. Furthermore, a moderate-intensity bout of exercise (60%) may be a more potent stimulant for improving cognitive function than low-intensity (40%) exercise. The present data should be considered by aeromedical personnel performing cognitive tasks in hypoxia.Seo Y, Gerhart HD, Stavres J, Fennell C, Draper S, Glickman EL. Normobaric hypoxia and submaximal exercise effects on running memory and mood state in women. Aerosp Med Hum Perform. 2017; 88(7):627-632.

  9. Effects of submaximal exercise and noise exposure on hearing loss.

    Science.gov (United States)

    Alessio, H M; Hutchinson, K M

    1991-12-01

    A recent Scandinavian study reported that persons cycling at moderate intensity for 10 min suffered hearing loss when the exercise was accompanied by noise. The noise consisted of a 1/3 octave band-filtered noise with a 2000 Hz center frequency at 104 dB SPL. In the present study, adults cycled at 50 rev.min-1 against a force that elicited an oxygen cost equal to 70% of VO2max--an intensity frequently recommended in exercise prescriptions--with and without noise administered via headphones. Repeated measures ANOVA with three factors revealed that although a temporary hearing loss occurred following exercise-and-noise, a similar and slightly greater hearing loss occurred following noise-only. Hearing sensitivity was not significantly altered by exercise-only (p greater than .05). In general, hearing loss values were greatest between 3000 and 4000 Hz. In conclusion, temporary hearing loss was driven by noise exposure, not exercise. However, persons who choose to exercise with personal headphones or in a noisy environment should be aware of potential premature hearing loss.

  10. The effect of pitched and vertical ladder ergometer climbing on cardiorespiratory and psychophysical variables.

    Science.gov (United States)

    Barron, P J; Burgess, K; Cooper, K; Stewart, A D

    2018-01-01

    This study aimed to assess whether modifying the pitch of a 75° ladder ergometer to vertical had a cardiorespiratory or psychophysical effect on climbing. Nine male participants climbed a ladder ergometer at 75° and subsequently at 90°, adjusted for an equivalent vertical climb rate, completing three climbing bouts at different vertical speeds. One participant dropped out being unable to complete the climb under the 90° condition. Each was monitored for heart rate (HR), V˙O2 and rating of perceived exertion (RPE). Results showed vertical climbing induced higher V˙O2 (mean increase 17.3%), higher HR (mean increase 15.8%), and higher RPE at all speeds and that moving from 75°to vertical exacerbates the effect of speed on the cardiorespiratory response to climbing. This may be explained by increased force production required to maintain balance in a vertical climbing position when the body's centre of mass is not above the feet. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Human calf muscular metabolism study with a home-made ergometer using 31P NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Peynsaert, J.; Achten, E.; Claeys, E. [Ghent University Hospital (Belgium); Rousseaux, M. [Ghent University Hospital (Belgium). Dept. of Sport Medicine

    1995-12-01

    Phosphorus-31 NMR measurements were performed to examine the variations in the concentration of phosphate metabolites in calf muscle during exercise. Therefore, volunteers, installed in the supine position, were asked to push repetitively on the pedal of a home-made ergometer. The produced work and the changes in phosphorus containing metabolites were measured continuously. Correlations were made between the inorganic phosphate/phosphocreatine ratio and the cumulative work and between the intracellular pH and the cumulative work. The exercise protocol could be changed interactively with respect to the imposed initial pressure, the maximum pressure, the pressure increase per level and the time a certain level was held. The whole experiment could be graphically followed on-line. In the first stadium, the in vitro reproducibility of the ergometer was tested for different protocols. These tests revealed that, though the deviation in produced work was markedly the highest at high working pressures, the relative error never exceeded 3%. Consequently, the ex vitro reproducibility of the data was examined with the equipment placed in the scanner. Generally, same conclusions could be derived. In a next stage, the work will be synchronized with the biochemical data. Extreme precautions will be taken to examine each volunteer every time under the same physical and psychological conditions.

  12. Racing Skiers and Swimmers’ Heart Electric Field during Ventricular Depolarization at Recovery Period after Moderate and Submaximal Physical Load

    Directory of Open Access Journals (Sweden)

    Svetlana V. Strelnikova

    2013-01-01

    Full Text Available The article presents the results of cardioelectrotopographic investigation of racing skiers and swimmers’ heart electric activity during ventricular depolarization at recovery period after moderate and submaximal physical load. Changes in ventricular depolarization time and ventricular depolarization phases ratio due to longer duration of the first and second cardioelectric potential inversions on the chest surface in racing skiers and less duration of the depolarization initial phase in swimmers were detected after moderate and submaximal load

  13. Iron Status in Chronic Heart Failure: Impact on Symptoms, Functional Class and Submaximal Exercise Capacity.

    Science.gov (United States)

    Enjuanes, Cristina; Bruguera, Jordi; Grau, María; Cladellas, Mercé; Gonzalez, Gina; Meroño, Oona; Moliner-Borja, Pedro; Verdú, José M; Farré, Nuria; Comín-Colet, Josep

    2016-03-01

    To evaluate the effect of iron deficiency and anemia on submaximal exercise capacity in patients with chronic heart failure. We undertook a single-center cross-sectional study in a group of stable patients with chronic heart failure. At recruitment, patients provided baseline information and completed a 6-minute walk test to evaluate submaximal exercise capacity and exercise-induced symptoms. At the same time, blood samples were taken for serological evaluation. Iron deficiency was defined as ferritin < 100 ng/mL or transferrin saturation < 20% when ferritin is < 800 ng/mL. Additional markers of iron status were also measured. A total of 538 heart failure patients were eligible for inclusion, with an average age of 71 years and 33% were in New York Heart Association class III/IV. The mean distance walked in the test was 285 ± 101 meters among those with impaired iron status, vs 322 ± 113 meters (P=.002). Symptoms during the test were more frequent in iron deficiency patients (35% vs 27%; P=.028) and the most common symptom reported was fatigue. Multivariate logistic regression analyses showed that increased levels of soluble transferrin receptor indicating abnormal iron status were independently associated with advanced New York Heart Association class (P < .05). Multivariable analysis using generalized additive models, soluble transferrin receptor and ferritin index, both biomarkers measuring iron status, showed a significant, independent and linear association with submaximal exercise capacity (P=.03 for both). In contrast, hemoglobin levels were not significantly associated with 6-minute walk test distance in the multivariable analysis. In patients with chronic heart failure, iron deficiency but not anemia was associated with impaired submaximal exercise capacity and symptomatic functional limitation. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  14. A Submaximal Running Test With Postexercise Cardiac Autonomic and Neuromuscular Function in Monitoring Endurance Training Adaptation.

    Science.gov (United States)

    Vesterinen, Ville; Nummela, Ari; Laine, Tanja; Hynynen, Esa; Mikkola, Jussi; Häkkinen, Keijo

    2017-01-01

    Vesterinen, V, Nummela, A, Laine, T, Hynynen, E, Mikkola, J, and Häkkinen, K. A submaximal running test with postexercise cardiac autonomic and neuromuscular function in monitoring endurance training adaptation. J Strength Cond Res 31(1): 233-243, 2017-The aim of this study was to investigate whether a submaximal running test (SRT) with postexercise heart rate recovery (HRR), heart rate variability (HRV), and countermovement jump (CMJ) measurements could be used to monitor endurance training adaptation. Thirty-five endurance-trained men and women completed an 18-week endurance training. Maximal endurance performance and maximal oxygen uptake were measured every 8 weeks. In addition, SRTs with postexercise HRR, HRV, and CMJ measurements were carried out every 4 weeks. Submaximal running test consisted of two 6-minute stages at 70 and 80% of maximum heart rate (HRmax) and a 3-minute stage at 90% HRmax, followed by a 2-minute recovery stage for measuring postexercise HRR, HRV, and CMJ test. The highest responders according to the change of maximal endurance performance showed a significant improvement in running speeds during stages 2 and 3 in SRT, whereas no changes were observed in the lowest responders. The strongest correlation was found between the change of maximal endurance performance and running speed during stage 3, whereas no significant relationships were found between the change of maximal endurance performance and the changes of postexercise HRR, HRV, and CMJ. Running speed at 90% HRmax intensity was the most sensitive variable to monitor adaptation to endurance training. The present submaximal test showed potential to monitor endurance training adaptation. Furthermore, it may serve as a practical tool for athletes and coaches to evaluate weekly the effectiveness of training program without interfering in the normal training habits.

  15. Effect of inspiratory muscle warm-up on submaximal rowing performance.

    Science.gov (United States)

    Arend, Mati; Mäestu, Jarek; Kivastik, Jana; Rämson, Raul; Jürimäe, Jaak

    2015-01-01

    Performing inspiratory muscle warm-up might increase exercise performance. The aim of this study was to investigate the impact of inspiratory muscle warm-up to submaximal rowing performance and to find if there is an effect on lactic acid accumulation and breathing parameters. Ten competitive male rowers aged between 19 and 27 years (age, 23.1 ± 3.8 years; height, 188.1 ± 6.3 cm; body mass, 85.6 ± 6.6 kg) were tested 3 times. During the first visit, maximal inspiratory pressure (MIP) assessment and the incremental rowing test were performed to measure maximal oxygen consumption and maximal aerobic power (Pamax). A submaximal intensity (90% Pamax) rowing test was performed twice with the standard rowing warm-up as test 1 and with the standard rowing warm-up and specific inspiratory muscle warm-up as test 2. During the 2 experimental tests, distance, duration, heart rate, breathing frequency, ventilation, peak oxygen consumption, and blood lactate concentration were measured. The only value that showed a significant difference between the test 1 and test 2 was breathing frequency (52.2 ± 6.8 vs. 53.1 ± 6.8, respectively). Heart rate and ventilation showed a tendency to decrease and increase, respectively, after the inspiratory muscle warm-up (p < 0.1). Despite some changes in respiratory parameters, the use of 40% MIP intensity warm-up is not suggested if the mean intensity of the competition is at submaximal level (at approximately 90% maximal oxygen consumption). In conclusion, the warm-up protocol of the respiratory muscles used in this study does not have a significant influence on submaximal endurance performance in highly trained male rowers.

  16. Neuromuscular control of a single twitch muscle in wild type and mutant Drosophila, measured with an ergometer.

    Science.gov (United States)

    Harvey, Jennifer; Brunger, Holly; Middleton, C Adam; Hill, Julia A; Sevdali, Maria; Sweeney, Sean T; Sparrow, John C; Elliott, Christopher J H

    2008-06-01

    How do deficits in neuronal growth, aging or synaptic function affect the final, mechanical output of a single muscle twitch? We address this in vivo (indeed in situ) with a novel ergometer that records the output of a large specialised muscle, the Drosophila jump muscle. Here, we describe in detail the ergometer, its construction and use. We evaluated the ergometer by showing that adult fly jump muscle output varies little between 3 h and 7 days; but newly eclosed flies produce only 65%. In a mutant with little octopamine (Tbetah), jump muscle performance is reduced by 28%. The initial responses of synaptic growth mutants (highwire and spinster) do not differ from wild type, as expected on the homeostatic hypothesis. However, responses in highwire mutations gradually decline following repeated stimuli, suggesting physiological as well as anatomical abnormalities. We conclude that the assay is robust, sensitive and reliable with a good throughput.

  17. Brain activity and perceived exertion during cycling exercise: an fMRI study.

    Science.gov (United States)

    Fontes, Eduardo B; Okano, Alexandre H; De Guio, François; Schabort, Elske J; Min, Li Li; Basset, Fabien A; Stein, Dan J; Noakes, Timothy D

    2015-04-01

    Currently, the equipment and techniques available to assess brain function during dynamic exercise are limited, which has restricted our knowledge of how the brain regulates exercise. This study assessed the brain areas activated during cycling by making use of a novel cycle ergometer, constructed to measure functional MRI (fMRI) brain images during dynamic exercise. Furthermore, we compared brain activation at different levels of ratings of perceived exertion (RPE) generated during the exercise. Seven healthy adults performed cycling exercise in a novel MRI compatible cycle ergometer while undergoing brain  fMRI. Participants completed a cycling block protocol comprising six trials of 2 min cycling with 16-s intervals between trials. Participants reported their RPE every minute through an audio link. The MRI cycling ergometer transferred the torque generated on the ergometer through a cardan system to a cycling ergometer positioned outside the MRI room. For data analysis, the effects of cycling as opposed to rest periods were examined after motion correction. The multiparticipant analysis revealed in particular the activation of the cerebellar vermis and precentral and postcentral gyrus when periods of cycling versus rest were compared. Single participant analysis in four participants revealed that activation of the posterior cingulate gyrus and precuneus occurred in cycling blocks perceived as 'hard' compared with exercise blocks that were less demanding. The present study offers a new approach to assess brain activation during dynamic cycling exercise, and suggests that specific brain areas could be involved in the sensations generating the rating of perceived exertion. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  18. Characteristics of track cycling.

    Science.gov (United States)

    Craig, N P; Norton, K I

    2001-01-01

    Track cycling events range from a 200 m flying sprint (lasting 10 to 11 seconds) to the 50 km points race (lasting approximately 1 hour). Unlike road cycling competitions where most racing is undertaken at submaximal power outputs, the shorter track events require the cyclist to tax maximally both the aerobic and anaerobic (oxygen independent) metabolic pathways. Elite track cyclists possess key physical and physiological attributes which are matched to the specific requirements of their events: these cyclists must have the appropriate genetic predisposition which is then maximised through effective training interventions. With advances in technology it is now possible to accurately measure both power supply and demand variables under competitive conditions. This information provides better resolution of factors that are important for training programme design and skill development.

  19. Characterization of Symmetry Properties of First Integrals for Submaximal Linearizable Third-Order ODEs

    Directory of Open Access Journals (Sweden)

    K. S. Mahomed

    2013-01-01

    Full Text Available The relationship between first integrals of submaximal linearizable third-order ordinary differential equations (ODEs and their symmetries is investigated. We obtain the classifying relations between the symmetries and the first integral for submaximal cases of linear third-order ODEs. It is known that the maximum Lie algebra of the first integral is achieved for the simplest equation and is four-dimensional. We show that for the other two classes they are not unique. We also obtain counting theorems of the symmetry properties of the first integrals for these classes of linear third-order ODEs. For the 5 symmetry class of linear third-order ODEs, the first integrals can have 0, 1, 2, and 3 symmetries, and for the 4 symmetry class of linear third-order ODEs, they are 0, 1, and 2 symmetries, respectively. In the case of submaximal linear higher-order ODEs, we show that their full Lie algebras can be generated by the subalgebras of certain basic integrals.

  20. The Usefulness of Submaximal Exercise Gas Exchange in Pulmonary Arterial Hypertension: A Case Series

    Directory of Open Access Journals (Sweden)

    Paul R. Woods

    2010-04-01

    Full Text Available Introduction Submaximal exercise gas exchange may be a useful tool to track responses to therapy in pulmonary arterial hypertension (PAH patients. Methods Three patients diagnosed with idiopathic PAH, on differing therapies, were included. Standard clinical tests (echocardiography; 6 minute walk were performed pre and 3-5 months after treatment. Gas exchange was measured during 3 minutes of step exercise at both time points. Results Gas exchange variables, end tidal CO 2 (P ET CO 2 and the ratio of ventilation to CO 2 production (V E /VCO 2 , during submaximal exercise were able to track patient responses to therapy over a 3-5 month period. Two patients demonstrated positive improvements, with an increased P ET CO 2 and decreased V E /VCO 2 during light exercise, in response to an altered therapeutic regime. The third patient had a worsening of gas exchange (decreased P ET CO 2 and increased V E /VCO 2 following no changes in the medical regime from the baseline visit. Conclusion Gas exchange variables measured during light submaximal exercise, such as P ET CO 2 and V E /VCO 2 , may be able to better detect small changes in functional status following treatment and could, therefore, be a useful tool to track disease severity in PAH patients. Further study is required to determine the clinical usefulness of these gas exchange variables.

  1. THE INFLUENCE OF OBESITY AND AMBIENT TEMPERATURE ON PHYSIOLOGICAL AND OXIDATIVE RESPONSES TO SUBMAXIMAL EXERCISE

    Directory of Open Access Journals (Sweden)

    N. Ahn

    2014-07-01

    Full Text Available This study investigated the effects of obesity and ambient temperature on physiological responses and markers of oxidative stress to submaximal exercise in obese and lean people. Sixteen healthy males were divided into an obese group (n=8, %fat: 27.00±3.00% and a lean group (n=8, %fat: 13.85±2.45%. Study variables were measured during a 60 min submaximal exercise test at 60% VO2max in a neutral (21±1°C and a cold (4±1°C environment. Heart rate, blood lactate, rectal temperature, serum levels of malondialdehyde (MDA and superoxide dismutase (SOD were measured at rest, during exercise and in recovery. Heart rate of both groups was significantly lower (P<0.05 in the cold than the warm environment, but there were no significant differences between the two groups. Serum SOD activity increased to a significantly greater extent (P<0.05 in the cold than the neutral environment, and remained elevated for longer during exercise in the obese group than the lean group. Serum MDA level during submaximal exercise was not significantly different between conditions or groups. Cold stress in exercise may challenge antioxidant defence mechanisms in obese subjects, but lipid peroxidation remains unchanged.

  2. Variation in heart rate during submaximal exercise: implications for monitoring training.

    Science.gov (United States)

    Lamberts, Robert P; Lemmink, Koen A P M; Durandt, Justin J; Lambert, Michael I

    2004-08-01

    A change in heart rate at a controlled submaximal exercise intensity is used as a marker of training status. However, the standard error of measurement has not been studied systematically, and therefore a change in heart rate, which can be considered relevant, has not been determined. Forty-four subjects (26.5 +/- 5.4 years; mean +/- standard deviation) participated in a submaximal running test at the same time of day for 5 consecutive days. Heart rates were determined during each of the 4 exercise intensities (2 minutes each) of increasing intensity and during the 1-minute recovery period after each stage. The repeatability of the heart rate on a day-to-day basis during the stages and recovery periods were high (intraclass correlation coefficient: 95% confidence interval R = 0.94- 0.99). The lowest variation in heart rate occurred in the fourth stage ( approximately 90% maximum heart rate) with heart rate varying 5 +/- 2 b.min(-1) (95% confidence interval for coefficient of variation = 1.1-1.4%). In conclusion, the standard error of measurement of submaximal heart rate is 1.1-1.4%. This magnitude of measurement error needs to be considered when heart rate is used as a marker of training status.

  3. Consequences of ankle joint fixation on FES cycling power output: a simulation study

    NARCIS (Netherlands)

    van Soest, A.J.; Gfohler, M.; Casius, L.J.R.

    2005-01-01

    Introduction: During fixed-ankle FES cycling in paraplegics, in which the leg position is completely determined by the crank angle, mechanical power output is low. This low power output limits the cardiovascular load that could be realized during FES ergometer cycling, and limits possibilities for

  4. Combined inhalation of beta2 -agonists improves swim ergometer sprint performance but not high-intensity swim performance

    DEFF Research Database (Denmark)

    Kalsen, Anders; Hostrup, Morten; Bangsbo, Jens

    2014-01-01

    ), in permitted doses within the World Anti-Doping Agency 2013 prohibited list, in elite swimmers with (AHR, n = 13) or without (non-AHR, n = 17) AHR. Maximal voluntary isometric contraction of m. quadriceps (MVC), sprint performance on a swim ergometer and performance in an exhaustive swim test at 110% of VO2max...... were determined. Venous plasma interleukin-6 (IL-6) and interleukin-8 (IL-8) were measured post-exercise. No improvement was observed in the exhaustive swim test, but swim ergometer sprint time was improved (P ...

  5. [Comparison of submaximal front crawl and breast stroke swimming in relation to energy expenditure].

    Science.gov (United States)

    Sugiyama, K; Katamoto, S

    1992-11-01

    The purpose of this study was to compare the energy expenditure during submaximal front crawl (Fr) and breast stroke (Br) swimming. Six male college swimmers performed submaximal and maximal exercise tests in both styles in a swimming flume. In submaximal exercise tests, they swam at the following given velocities for 5 min, Br: 0.3, 0.5 and 0.7 m/sec; Fr: 0.3, 0.5, 0.7 and 0.9 m/sec. In maximal exercise tests, following submaximal swimming at 0.9 m/sec in Br and 1.1 m/sec in Fr, swimming velocity was increased progressively by 0.1 m/sec every 1 min until the subjects reached to voluntary exhaustion. VO2max obtained from the maximal swimming tests in Br and Fr were 4.27 and 4.18 l/min, respectively. And there was no significant difference between these two values. VO2 during Br and Fr swimming at four and five submaximal velocities were 1.06, 1.30, 1.79, 2.65 l/min and 1.17, 1.34, 1.63, 2.04, 3.05 l/min, respectively. And, it was found that VO2 at 0.3 and 0.9 m/sec were significantly different (p styles curvilinearly increased with swimming velocity, and these relationships were well fitted for the regression equation of the second order (Br: y = 3.84625x2 - 1.95914x + 1.310463,r2 = 0.999 (p < 0.05), Fr: y = 3.233446x2 - 2.28136x + 1.611524, r2 = 0.979 (p < 0.05)). It was calculated that the two curves crossed at a point on 0.49 m/sec, and that VO2 at this point was 1.27 l/min. This value equivalented to 30.4% VO2max in Br and 29.7% VO2max in Fr.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Effect of strength training with blood flow restriction on muscle power and submaximal strength in eumenorrheic women.

    Science.gov (United States)

    Gil, Ana L S; Neto, Gabriel R; Sousa, Maria S C; Dias, Ingrid; Vianna, Jeferson; Nunes, Rodolfo A M; Novaes, Jefferson S

    2017-03-01

    Blood flow restriction (BFR) training stimulates muscle size and strength by increasing muscle activation, accumulation of metabolites and muscle swelling. This method has been used in different populations, but no studies have evaluated the effects of training on muscle power and submaximal strength (SS) in accounted for the menstrual cycle. The aim of this study was to analyse the effect of strength training (ST) with BFR on the muscle power and SS of upper and lower limbs in eumenorrheic women. Forty untrained women (18-40 years) were divided randomly and proportionally into four groups: (i) high-intensity ST at 80% of 1RM (HI), (ii) low-intensity ST at 20% of 1RM combined with partial blood flow restriction (LI + BFR), (iii) low-intensity ST at 20% of 1RM (LI) and d) control group (CG). Each training group performed eight training sessions. Tests with a medicine ball (MB), horizontal jump (HJ), vertical jump (VJ), biceps curls (BC) and knee extension (KE) were performed during the 1st day follicular phase (FP), 14th day (ovulatory phase) and 26-28th days (luteal phase) of the menstrual cycle. There was no significant difference among groups in terms of the MB, HJ, VJ or BC results at any time point (P>0·05). SS in the KE exercise was significantly greater in the LI + BFR group compared to the CG group (P = 0·014) during the LP. Therefore, ST with BFR does not appear to improve the power of upper and lower limbs and may be an alternative to improve the SS of lower limbs of eumenorrheic women. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  7. Mean power during 20 sec all-out test to predict 2000 m rowing ergometer performance in national level young rowers.

    Science.gov (United States)

    Cataldo, A; Cerasola, D; Russo, G; Zangla, D; Traina, M

    2015-09-01

    The aim of this study was to assess the relationship between mean power during 20 s all-out rowing ergometer test and 2000 m rowing ergometer performance, in 20 young male rowers (mean age 15.2±1.3 years). Mean power during 20 s all-out test (W20), maximal oxygen uptake during incremental test (VO2max), and anthropometric values, were measured and correlated with the time to perform a 2000 m trial (t2000). W20 showed the highest correlation with t2000 (r=-0.947, Prowing ergometer performance time was accounted for by W20. These results suggest that W20 is an important predictor of 2000 m rowing ergometer performance, and the 20 s all-out test on rowing ergometer may be a useful monitoring tool for young rowers.

  8. [Submaximal exercise capacity and quality of life in exclusive water-pipe smokers].

    Science.gov (United States)

    Ben Saad, H; Babba, M; Boukamcha, R; Latiri, I; Knani, J; Slama, R; Bougmiza, I; Zbidi, A; Tabka, Z

    2010-05-01

    It is well known that oxidative stress is increased significantly by regular water-pipe smoking (WPS). This could lead to muscle dysfunction and thus to impairments of exercise and quality of life (QOL). Considering the impressive number of WP smokers, we intend to investigate the potential effect of WPS on submaximal exercise capacity and QOL. (1). To evaluate the submaximal exercise capacity by the 6-minutes walking test (6-MWT). (2). To compare the deficiency, incapacity and QOL data of exclusive WPS with those of two control groups (never smokers and exclusive cigarette smokers). (3). To determine the factors influencing the 6-minutes walk distance (6-MWD) of WPS subjects. A multicentre study including 180 exclusive WPS [> or =5 WP-year] men aged > or =40 years. Cigar or cigarette smoking, contraindications to the 6-MWT or cortico-steroid therapy will be exclusion criteria. QOL evaluation, spirometry, electrocardiogram and two 6-MWT will be performed. Signs of exercise impairment will be: 6-MWD or =5/10, haemoglobin saturation fall > or =5 points. Data from WPS subjects will be compared with those from 90 never smoking subjects and 90 exclusives cigarettes smokers. (1). WPS will affect significantly the submaximal exercise capacity. (2). Resting spirometric, 6-MWT and QOL data of exclusive WPS subjects will be significantly reduced compared to never smoking subjects. (3). The 6-MWD's of exclusive WPS subjects will be significantly influenced by cumulative WP consumption, by resting spirometric data, by obesity and by physical activity score. Copyright 2010 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  9. The Impact of a Submaximal Level of Exercise on Balance Performance in Older Persons

    Science.gov (United States)

    2014-01-01

    Objective. The purpose of this study was to determine the impact of a submaximal level of exercise on balance performance under a variety of conditions. Material and Method. Thirteen community-dwelling older persons with intact foot sensation (age = 66.69 ± 8.17 years, BMI = 24.65 ± 4.08 kg/m2, female, n = 6) volunteered to participate. Subjects' balance performances were measured using the Modified Clinical Test of Sensory Integration of Balance (mCTSIB) at baseline and after test, under four conditions of stance: (1) eyes-opened firm-surface (EOF), (2) eyes-closed firm-surface (ECF), (3) eyes-opened soft-surface (EOS), and (4) eyes-closed soft-surface (ECS). The 6-minute walk test (6MWT) protocol was used to induce the submaximal level of exercise. Data was analyzed using the Wilcoxon Signed-Rank Test. Results. Balance changes during EOF (z = 0.00, P = 1.00) and ECF (z = −1.342, P = 0.180) were not significant. However, balance changes during EOS (z = −2.314, P = 0.021) and ECS (z = −3.089, P = 0.02) were significantly dropped after the 6MWT. Conclusion. A submaximal level of exercise may influence sensory integration that in turn affects balance performance, particularly on an unstable surface. Rehabilitation should focus on designing intervention that may improve sensory integration among older individuals with balance deterioration in order to encourage functional activities. PMID:25383386

  10. Hypotension and heart rate variability after resistance exercise performed maximal and submaximal order

    Directory of Open Access Journals (Sweden)

    Victor Gonçalves Corrêa Neto

    2017-06-01

    Full Text Available The aim of the study was verified the blood pressure responses and the cardiac autonomic modulation after the strength exercise in two different conditions (maximal and submaximal. The subjects were divided in three groups, such as: maximal repetitions (age: 20.5 ± 0.6 years, weight: 63.7 ± 14.8, height: 1.7 ± 0.1, body mass index: 22.8 ± 4.5 Kilogram per square meter (kg/m², submaximal repetitions (age: 25 ± 4.1 years, weight: 69.1 ± 12.8, height: 1.8 ± 0.1, body mass index: 22.2 ± 1.7 (kg/m²  and a control group (age: 23.7 ± 3.8 years, weight: 64.2 ± 15, height: 1.7 ± 0.1, body mass index: 21.8 ± 1.9 (kg/m². The blood pressure and the Heart Rate R-R intervals were measured before and during one hour after the session, with 10-minutes intervals length between measurements. The analyze of variance did not showed significant differences between experimental protocols to blood pressure (p > 0.05. However, the effect size was able to show that the most intense training caused a reduction in systolic blood pressure at times. Regarding cardiac autonomic response, the group that exercised the submaximal form exhibited a significant increase in LF / HF (p = 0.022 when 20 minutes’ post-exercise. There was a not significant difference in cardiac autonomic modulation between protocols. The high intensity protocol has caused blood pressure reductions in more moments and it was over safer in relation to cardiac autonomic modulation, since it did not cause increased sympathetic activity during recovery.

  11. Comparison of the YMCA and a Custom Submaximal Exercise Test for Determining VO2max.

    Science.gov (United States)

    Jamnick, Nicholas A; By, Savanny; Pettitt, Cherie D; Pettitt, Robert W

    2016-02-01

    The maximal oxygen uptake (VO2max) is deemed the highest predictor for all-cause mortality, and therefore, an ability to assess VO2max is important. The YMCA submaximal test is one of the most widely used tests to estimate VO2max; however, it has questionable validity. We validated a customized submaximal test that accounts for the nonlinear rise in VO2 relative to power output and compared its accuracy against the YMCA protocol. Fifty-six men and women performed a graded exercise test with a subsequent exhaustive, square wave bout for the verification of "true" VO2max. In counterbalanced order, subjects then completed the YMCA test and our new Mankato submaximal exercise test (MSET). The MSET consisted of a 3-min stage estimated at 35% VO2max and a second 3-min stage estimated at either 65% or 70% VO2max, where VO2max was estimated with a regression equation using sex, body mass index, age, and self-reported PA-R. VO2 values from the graded exercise test and square wave verification bout did not differ with the highest value used to identify "true" VO2max (45.1 ± 8.89 mL · kg(-1) · min(-1)). The MSET (43.6 ± 8.6 mL · kg(-1) · min(-1)) did not differ from "true" VO2max, whereas the YMCA test (41.1 ± 9.6 mL · kg(-1) · min(-1)) yielded an underestimation (P = 0.002). The MSET was moderately correlated with "true" VO2max (ICC = 0.73, CV of 11.3%). The YMCA test was poorly correlated with "true" VO2max (ICC = 0.29, CV of 15.1%). To our knowledge, this is the first study to examine submaximal exercise protocols versus a verified VO2max protocol. The MSET yielded better estimates of VO2max because of the protocol including a stage exceeding gas exchange threshold.

  12. Coconut Water Does Not Improve Markers of Hydration During Sub-maximal Exercise and Performance in a Subsequent Time Trial Compared with Water Alone.

    Science.gov (United States)

    Peart, Daniel J; Hensby, Andy; Shaw, Matthew P

    2017-06-01

    The purpose of this study was to compare markers of hydration during submaximal exercise and subsequent time trial performance when consuming water (PW) or coconut water (CW). There was also a secondary aim to assess the palatability of CW during exercise and voluntary intake during intense exercise. 10 males (age 27.9 ± 4.9 years, body mass 78.1 ± 10.1kg, average max minute power 300.2 ± 28.2W) completed 60-min of submaximal cycling followed by a 10-km time trial on two occasions. During these trials participants consumed either PW or CW in a randomized manner, drinking a 250 ml of the assigned drink between 10-15 min, 25-30 min and 40-45 min, and then drinking ad libitum from 55-min until the end of the time trial. Body mass and urine osmolality were recorded preexercise and then after 30-min, 60-min, and post time trial. Blood glucose, lactate, heart rate, rate of perceived exertion (RPE; 6-20) and ratings of thirst, sweetness, nausea, fullness and stomach upset (1 =very low/none, 5= very high) were recorded during each drink period. CW did not significantly improve time trial performance compared with PW (971.4 ± 50.5 and 966.6 ± 44.8 s respectively; p = .698) and there was also no significant differences between trials for any of the physiological variables measured. However there were subjective differences between the beverages for taste, resulting in a significantly reduced volume of voluntary intake in the CW trial (115 ± 95.41 ml and 208.7 ± 86.22 ml; p < .001).

  13. Effects of a helium/oxygen mixture on individuals’ lung function and metabolic cost during submaximal exercise for participants with obstructive lung diseases

    Directory of Open Access Journals (Sweden)

    Häussermann S

    2015-09-01

    Full Text Available Sabine Häussermann,1 Anja Schulze,1 Ira M Katz,2,3 Andrew R Martin,4 Christiane Herpich,1 Theresa Hunger,1 Joëlle Texereau2 1Inamed GmbH, Gauting, Germany; 2Medical R&D, Air Liquide Santé International, Centre de Recherche Paris-Saclay, Les Loges-en-Josas, France; 3Department of Mechanical Engineering, Lafayette College, Easton, PA, USA; 4Department of Mechanical Engineering, University of Alberta, Edmonton, AB, CanadaBackground: Helium/oxygen therapies have been studied as a means to reduce the symptoms of obstructive lung diseases with inconclusive results in clinical trials. To better understand this variability in results, an exploratory physiological study was performed comparing the effects of helium/oxygen mixture (78%/22% to that of medical air.Methods: The gas mixtures were administered to healthy, asthmatic, and chronic obstructive pulmonary disease (COPD participants, both moderate and severe (6 participants in each disease group, a total of 30; at rest and during submaximal cycling exercise with equivalent work rates. Measurements of ventilatory parameters, forced spirometry, and ergospirometry were obtained.Results: There was no statistical difference in ventilatory and cardiac responses to breathing helium/oxygen during submaximal exercise. For asthmatics, but not for the COPD participants, there was a statistically significant benefit in reduced metabolic cost, determined through measurement of oxygen uptake, for the same exercise work rate. However, the individual data show that there were a mixture of responders and nonresponders to helium/oxygen in all of the groups.Conclusion: The inconsistent response to helium/oxygen between individuals is perhaps the key drawback to the more effective and widespread use of helium/oxygen to increase exercise capacity and for other therapeutic applications. Keywords: helium/oxygen, inspiratory capacity, oxygen uptake, COPD, asthma, obstructive airway diseases, exercise, heliox

  14. Estimating Neural Control from Concentric vs. Eccentric Surface Electromyographic Representations during Fatiguing, Cyclic Submaximal Back Extension Exercises

    Directory of Open Access Journals (Sweden)

    Gerold R. Ebenbichler

    2017-05-01

    Full Text Available Purpose: To investigate the differences in neural control of back muscles activated during the eccentric vs. the concentric portions of a cyclic, submaximal, fatiguing trunk extension exercise via the analysis of amplitude and time-frequency parameters derived from surface electromyographic (SEMG data.Methods: Using back dynamometers, 87 healthy volunteers performed three maximum voluntary isometric trunk extensions (MVC's, an isometric trunk extension at 80% MVC, and 25 cyclic, dynamic trunk extensions at 50% MVC. Dynamic testing was performed with the trunk angular displacement ranging from 0° to 40° and the trunk angular velocity set at 20°/s. SEMG data was recorded bilaterally from the iliocostalis lumborum at L1, the longissimus dorsi at L2, and the multifidus muscles at L5. The initial value and slope of the root mean square (RMS-SEMG and the instantaneous median frequency (IMDF-SEMG estimates derived from the SEMG recorded during each exercise cycle were used to investigate the differences in MU control marking the eccentric vs. the concentric portions of the exercise.Results: During the concentric portions of the exercise, the initial RMS-SEMG values were almost twice those observed during the eccentric portions of the exercise. The RMS-SEMG values generally increased during the concentric portions of the exercise while they mostly remained unchanged during the eccentric portions of the exercise with significant differences between contraction types. Neither the initial IMDF-SEMG values nor the time-course of the IMDF-SEMG values significantly differed between the eccentric and the concentric portions of the exercise.Conclusions: The comparison of the investigated SEMG parameters revealed distinct neural control strategies during the eccentric vs. the concentric portions of the cyclic exercise. We explain these differences by relying upon the principles of orderly recruitment and common drive governing motor unit behavior.

  15. Muscle coordination, activation and kinematics of world-class and elite breaststroke swimmers during submaximal and maximal efforts.

    Science.gov (United States)

    Olstad, Bjørn Harald; Vaz, João Rocha; Zinner, Christoph; Cabri, Jan M H; Kjendlie, Per-Ludvik

    2017-06-01

    The aims of this study were to describe muscular activation patterns and kinematic variables during the complete stroke cycle (SC) and the different phases of breaststroke swimming at submaximal and maximal efforts. Surface electromyography (sEMG) was collected from eight muscles in nine elite swimmers; five females (age 20.3 ± 5.4 years; Fédération Internationale de Natation [FINA] points 815 ± 160) and four males (27.7 ± 7.1 years; FINA points 879 ± 151). Underwater cameras were used for 3D kinematic analysis with automatic motion tracking. The participants swam 25 m of breaststroke at 60%, 80% and 100% effort and each SC was divided into three phases: knee extension, knee extended and knee flexion. With increasing effort, the swimmers decreased their SC distance and increased their velocity and stroke rate. A decrease during the different phases was found for duration during knee extended and knee flexion, distance during knee extended and knee angle at the beginning of knee extension with increasing effort. Velocity increased for all phases. The mean activation pattern remained similar across the different effort levels, but the muscles showed longer activation periods relative to the SC and increased integrated sEMG (except trapezius) with increasing effort. The muscle activation patterns, muscular participation and kinematics assessed in this study with elite breaststroke swimmers contribute to a better understanding of the stroke and what occurs at different effort levels. This could be used as a reference for optimising breaststroke training to improve performance.

  16. The effect on cardiorespiratory fitness after an 8-week period of commuter cycling - A randomized controlled study in adults

    DEFF Research Database (Denmark)

    Møller, Niels Christian; Østergaard, Lars; Gade, Jens Raaberg

    2011-01-01

    change in lifestyle" or to "minimum 20minutes of daily commuter cycling during 8weeks". Maximal oxygen uptake was assessed directly during a progressive cycle-ergometer-test, sum of skinfolds was used as an estimate of body fat, and blood pressure was measured using a Dinamap monitor. Measurements were...

  17. Comparison of oxygen uptake during and after the execution of resistance exercises and exercises performed on ergometers, matched for intensity

    Directory of Open Access Journals (Sweden)

    Vilaça-Alves José

    2016-12-01

    Full Text Available The aim of this study was to compare the values of oxygen uptake (VO2 during and after strength training exercises (STe and ergometer exercises (Ee, matched for intensity and exercise time. Eight men (24 ± 2.33 years performed upper and lower body cycling Ee at the individual’s ventilatory threshold (VE/VCO2. The STe session included half squats and the bench press which were performed with a load at the individual blood lactate concentration of 4 mmol/l. Both sessions lasted 30 minutes, alternating 50 seconds of effort with a 10 second transition time between upper and lower body work. The averaged overall VO2 between sessions was significantly higher for Ee (24.96 ± 3.6 ml·kg·min-1 compared to STe (21.66 ± 1.77 ml·kg·min-1 (p = 0.035, but this difference was only seen for the first 20 minutes of exercise. Absolute VO2 values between sessions did not reveal differences. There were more statistically greater values in Ee compared to STe, regarding VO2 of lower limbs (25.44 ± 3.84 ml·kg·min-1 versus 21.83 ± 2·24 ml·kg·min-1; p = 0.038 and upper limbs (24.49 ± 3.84 ml·kg·min-1 versus 21.54 ± 1.77 ml·kg·min-1; p = 0.047. There were further significant differences regarding the moment effect (p<0.0001 of both STe and Ee sessions. With respect to the moment × session effect, only VO2 5 minutes into recovery showed significant differences (p = 0.017. In conclusion, although significant increases in VO2 were seen following Ee compared to STe, it appears that the load/intensity, and not the material/equipment used for the execution of an exercise, are variables that best influence oxygen uptake.

  18. Applied physiology of cycling.

    Science.gov (United States)

    Faria, I E

    1984-01-01

    Historically, the bicycle has evolved through the stages of a machine for efficient human transportation, a toy for children, a finely-tuned racing machine, and a tool for physical fitness development, maintenance and testing. Recently, major strides have been made in the aerodynamic design of the bicycle. These innovations have resulted in new land speed records for human powered machines. Performance in cycling is affected by a variety of factors, including aerobic and anaerobic capacity, muscular strength and endurance, and body composition. Bicycle races range from a 200m sprint to approximately 5000km. This vast range of competitive racing requires special attention to the principle of specificity of training. The physiological demands of cycling have been examined through the use of bicycle ergometers, rollers, cycling trainers, treadmill cycling, high speed photography, computer graphics, strain gauges, electromyography, wind tunnels, muscle biopsy, and body composition analysis. These techniques have been useful in providing definitive data for the development of a work/performance profile of the cyclist. Research evidence strongly suggests that when measuring the cyclist's aerobic or anaerobic capacity, a cycling protocol employing a high pedalling rpm should be used. The research bicycle should be modified to resemble a racing bicycle and the cyclist should wear cycling shoes. Prolonged cycling requires special nutritional considerations. Ingestion of carbohydrates, in solid form and carefully timed, influences performance. Caffeine appears to enhance lipid metabolism. Injuries, particularly knee problems which are prevalent among cyclists, may be avoided through the use of proper gearing and orthotics. Air pollution has been shown to impair physical performance. When pollution levels are high, training should be altered or curtailed. Effective training programmes simulate competitive conditions. Short and long interval training, blended with long

  19. Cognitive Performance Enhancement Induced by Caffeine, Carbohydrate and Guarana Mouth Rinsing during Submaximal Exercise

    Directory of Open Access Journals (Sweden)

    Laura Pomportes

    2017-06-01

    Full Text Available The aim of this study was to investigate the influence of serial mouth rinsing (MR with nutritional supplements on cognitive performance (i.e., cognitive control and time perception during a 40-min submaximal exercise. Twenty-four participants completed 4 counterbalanced experimental sessions, during which they performed MR with either placebo (PL, carbohydrate (CHO: 1.6 g/25 mL, guarana complex (GUAc: 0.4 g/25 mL or caffeine (CAF: 67 mg/25 mL before and twice during exercise. The present study provided some important new insights regarding the specific changes in cognitive performance induced by nutritional supplements. The main results were: (1 CHO, CAF and GUA MR likely led participants to improve temporal performance; (2 CAF MR likely improved cognitive control; and (3 CHO MR led to a likely decrease in subjective perception of effort at the end of the exercise compared to PL, GUA and CAF. Moreover, results have shown that performing 40-min submaximal exercise enhances information processing in terms of both speed and accuracy, improves temporal performance and does not alter cognitive control. The present study opens up new perspectives regarding the use of MR to optimize cognitive performance during physical exercise.

  20. Reliability of heart rate variability threshold and parasympathetic reactivation after a submaximal exercise test

    Directory of Open Access Journals (Sweden)

    Carlos Janssen Gomes da Cruz

    Full Text Available Abstract The objective of this study was to evaluate reproducibility of heart rate variability threshold (HRVT and parasympathetic reactivation in physically active men (n= 16, 24.3 ± 5.1 years. During the test, HRVT was assessed by SD1 and r-MSSD dynamics. Immediately after exercise, r-MSSD was analyzed in segments of 60 seconds for a period of five minutes. High absolute and relatively reproducible analysis of HRVT were observed, as assessed by SD1 and r-MSSD dynamics (ICC = 0.92, CV = 10.8, SEM = 5.8. During the recovery phase, a moderate to high reproducibility was observed for r-MSSD from the first to the fifth minute (ICC = 0.69-0.95, CV = 7.5-14.2, SEM = 0.07-1.35. We conclude that HRVT and r-MSSD analysis after a submaximal stress test are highly reproducible measures that might be used to assess the acute and chronic effects of exercise training on cardiac autonomic modulation during and/or after a submaximal stress test.

  1. [Sub-maximal aerobic capacity and quality of life of patients with rheumatoid arthritis].

    Science.gov (United States)

    Lataoui, S; Belghali, S; Zeglaoui, H; Bouajina, E; Ben Saad, H

    2017-01-01

    Studies about sub-maximal aerobic capacity of patients with rheumatoid arthritis are scarce. To assess the sub-maximal aerobic capacity of these patients through the 6-min walk test, estimated age of the "muscular and cardiorespiratory" chain. Thirty-seven consecutive patients (aged 20 to 60 years) with newly diagnosed rheumatoid arthritis will be included. Non-inclusion criteria will be: use of drugs (e.g.; methotrexate, beta-blockers), orthopaedic or rheumatologic conditions (other than rheumatoid arthritis) that may alter walking ability and recent infections. Exclusion criteria will be: 6-min walking test contra-indications and imperfect performance of the required lung function and walking maneuvers. Signs of walking intolerance will be: test interruption, distance ≤lower limit of normal, dyspnea score ≥5/10 (visual analogue scale) at the end of the test, haemoglobin oxygen saturation (SpO2) drop ≥5%, cardiac frequency at the end of the test ≤60% of maximum predicted. An estimated "muscular and cardiorespiratory chain" age higher than the chronological one will be considered as a sign of accelerated ageing. A high percentage of patients suffering from rheumatoid arthritis would show evidences of walking limitation and accelerated "muscular and cardiorespiratory chain" ageing. There would be a significant correlation between the walking test and clinical, biological, radiological and pulmonary function data and the patients' quality-of-life status. Copyright © 2016 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  2. Relationship between rowing ergometer performance and physiological responses to upper and lower body exercises in rowers.

    Science.gov (United States)

    Jürimäe, Toivo; Perez-Turpin, Jose A; Cortell-Tormo, Joan M; Chinchilla-Mira, Ivan J; Cejuela-Anta, Roberto; Mäestu, Jarek; Purge, Priit; Jürimäe, Jaak

    2010-07-01

    The aim of this investigation was to compare the physiological responses of 2000 m rowing ergometer test with 7-min bench pull and leg press tests. We hypothesised that leg press exercise contributes to 2000 m rowing ergometer test results, rather than bench pull performed by arms. College level rowers (n=12) performed 2000 m rowing test and after one day 7-min bench pull and leg press (50% from the 1 RM). Stroke rate, heart rate (HR), blood lactate (LA) and ratings of perceived exertion (RPE) were measured during all tests. The number of repetitions was highest during 2000 m rowing test (194.2+/-19.5) and lowest during bench pull (122.6+/-17.7) (during leg press 173.5+/-11.8). Differences between 2000 m rowing test, leg press and bench pull tests were significant in mean and maximal HR. In LA concentration, the highest values were at 3rd min of recovery after rowing test (14.8+/-1.7 mmol l(-1)). Between bench pull (8.8+/-1.9 and 8.5+/-2.7 mmol l(-1)) and leg press (11.8+/-2.5 and 11.2+/-2.3 mmol l(-1)) tests, the difference in LA concentration was not significant (p>0.05). Ratings of perceived exertion were highest in 2000 m rowing test (19.3+/-0.9), difference with leg press and bench pull tests was not significant. There were significant relationships in mean and maximal HR (r=0.713-0.767) and Borg scale (r=0.764) during rowing test and leg press. The number of repetitions during leg press exercise correlated significantly with rowing test time (r=-0.677). In conclusion, this study suggests that in rowers there are major differences in the physiological adaptation to upper body and leg exercise, performed at similar intensities. Leg press exercise could be used to measure sport-specific strength endurance in rowers. Copyright 2009. Published by Elsevier Ltd.

  3. Impact of a Submaximal Warm-Up on Endurance Performance in Highly Trained and Competitive Male Runners

    Science.gov (United States)

    Zourdos, Michael C.; Bazyler, Caleb D.; Jo, Edward; Khamoui, Andy V.; Park, Bong-Sup; Lee, Sang-Rok; Panton, Lynn B.; Kim, Jeong-Su

    2017-01-01

    Purpose: The purpose of this investigation was to examine the effects of a submaximal running warm-up on running performance in male endurance athletes (n = 16, M[subscript age] = 21 ± 2 years, M[subscript VO2max] = 69.3 ± 5.1 mL/kg/min). Method: Endurance performance was determined by a 30-min distance trial after control and submaximal running…

  4. The influence of evaluation protocol on time spent exercising at a high level of oxygen uptake during continuous cycling

    OpenAIRE

    Merry, KL; Glaister, Mark; Howatson, Glyn; Van Someren, Ken A.

    2015-01-01

    AIM: This study evaluated the effects of protocol variation on the time spent exercising at ≥95% .VO2max during cycle ergometer trials performed at the exercise intensity associated with .VO2max (i .VO2max).\\ud METHODS: Nine male triathletes (age: 32±10 years; body mass: 73.3±6.1 kg; stature: 1.79±0.07 m; .VO2max: 3.58±0.45 L.min-1) performed four exercise tests. During tests 1 and 2, participants performed a maximal incremental cycle ergometer test using different stage durations (1 min and ...

  5. A new proposal to guide velocity and inclination in the ramp protocol for the treadmill ergometer

    Directory of Open Access Journals (Sweden)

    Silva Odwaldo Barbosa e

    2003-01-01

    Full Text Available OBJECTIVE: To suggest criteria to guide protocol prescription in ramp treadmill testing, according to sex and age, based on velocity, inclination, and max VO2 reached by the population studied. METHODS: Prospective study describing heart rate (HR, time, velocity, inclination, and VO2 estimated at maximum effort of 1840 individuals from 4 to 79 years old, who performed a treadmill test (TT according to the ramp protocol. A paired Student t test was used to assess the difference between predicted and reached max VO2, calculated according to the formulas of the "American College of Sports Medicine". RESULTS: Submaximal HR was surpassed in 90.1% of the examinations, with a mean time of 10.0±2.0 minute. Initial and peak inclination velocity of the exercise and max VO2 were inversely proportional to age and were greater in male patients. Predicted Max VO2 was significantly lower than that reached in all patients, except for female children and adolescents (age < 20 years old. CONCLUSION: Use of velocity, inclination, and maximum VO2 actually reached, as a criterion in prescribing the ramp protocol may help in the performance of exercise in treadmill testing. The ramp protocol was well accepted in all age groups and sexes with exercise time within the programmed 8 to 12 minutes.

  6. Effects of 16-week high-intensity interval training using upper and lower body ergometers on aerobic fitness and morphological changes in healthy men: a preliminary study.

    Science.gov (United States)

    Osawa, Yusuke; Azuma, Koichiro; Tabata, Shogo; Katsukawa, Fuminori; Ishida, Hiroyuki; Oguma, Yuko; Kawai, Toshihide; Itoh, Hiroshi; Okuda, Shigeo; Matsumoto, Hideo

    2014-01-01

    It is unclear whether combined leg and arm high-intensity interval training (HIIT) improves fitness and morphological characteristics equal to those of leg-based HIIT programs. The aim of this study was to compare the effects of HIIT using leg-cycling (LC) and arm-cranking (AC) ergometers with an HIIT program using only LC. Effects on aerobic capacity and skeletal muscle were analyzed. Twelve healthy male subjects were assigned into two groups. One performed LC-HIIT (n=7) and the other LC- and AC-HIIT (n=5) twice weekly for 16 weeks. The training programs consisted of eight to 12 sets of >90% VO2 (the oxygen uptake that can be utilized in one minute) peak for 60 seconds with a 60-second active rest period. VO2 peak, watt peak, and heart rate were measured during an LC incremental exercise test. The cross-sectional area (CSA) of trunk and thigh muscles as well as bone-free lean body mass were measured using magnetic resonance imaging and dual-energy X-ray absorptiometry. The watt peak increased from baseline in both the LC (23%±38%; Phypertrophy in both leg and trunk muscles.

  7. Ergometer training volume and previous injury predict back pain in rowing; strategies for injury prevention and rehabilitation.

    Science.gov (United States)

    Wilson, Fiona; Gissane, Conor; McGregor, Alison

    2014-11-01

    The most commonly reported injury site in rowers is the lower back. Research in recent years has focused on epidemiology and biomechanical analyses to try and understand mechanisms that contribute to this injury's onset. Injury surveillance mainly comprises retrospective questionnaires and reviews of medical records with a lack of prospective data. Of studies that reported 12-month data, the incidence of low back pain ranged from 31.8 to 51% of the cohort. Of the limited studies that specifically examined low back pain in rowers, (1) history of lumbar spine injury and (2) volume of ergometer training were the most significant risk factors for injury onset. Studies of technique on the rowing ergometer have indicated the importance of lumbopelvic rotation during rowing. Greater pelvic rotation at either end of the stroke is ideal-as opposed to lumbar flexion and extension; this tends to be poorly demonstrated in novice rowers on ergometers. Furthermore, technique can deteriorate with the demands of rowing intensity and duration, which puts the rower returning from injury at additional risk. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  8. Effects of caloric restriction and overnight fasting on cycling endurance performance.

    Science.gov (United States)

    Ferguson, Lisa M; Rossi, Kelly A; Ward, Emily; Jadwin, Emily; Miller, Todd A; Miller, Wayne C

    2009-03-01

    In addition to aerobic endurance and anaerobic capacity, high power-to-weight ratio (PWR) is important for cycling performance. Cyclists often try to lose weight before race season to improve body composition and optimize PWR. Research has demonstrated body fat-reducing benefits of exercise after fasting overnight. We hypothesized that fasted-state exercise in calorie-restricted trained cyclists would not result in performance decrements and that their PWR would improve significantly. We also hypothesized that substrate use during fasted-state submaximal endurance cycling would shift to greater reliance on fat. Ten trained, competitive cyclists completed a protocol consisting of baseline testing, 3 weeks of caloric restriction (CR), and post-CR testing. The testing sessions measured pre- and post-CR values for resting metabolic rate (RMR), body composition, VO2, PWR and power-to-lean weight ratio (PLWR), and power output, as well as 2-hour submaximal cycling performance, rating of perceived exertion (RPE), and respiratory exchange ratio (RER). There were no significant differences between baseline and post-CR for submaximal trial RER, power output, VO2, RMR, VO2max, or workload at VO2max. However, RPE was significantly lower, and PWR was significantly higher post-CR, whereas RER did not change. The cyclists' PWR and body composition improved significantly, and their overall weight, fat weight, and body fat percentage decreased. Lean mass was maintained. The cyclists' RPE decreased significantly during 2 hours of submaximal cycling post-CR, and there was no decrement in submaximal or maximal cycling performance after 3 weeks of CR combined with overnight fasting. Caloric restriction (up to 40% for 3 weeks) and exercising after fasting overnight can improve a cyclist's PWR without compromising endurance cycling performance.

  9. Prognostic value of treadmill stress echocardiography at extremes of exercise performance: submaximal high exercise capacity ≥ 10 metabolic equivalents.

    Science.gov (United States)

    Yao, Siu-Sun; Agarwal, Vikram; Chaudhry, Farooq A

    2014-03-01

    Submaximal stress testing or achieving High exercise capacity (≥ 10 metabolic equivalents, METS) is a predictor of favorable prognosis. The purpose of this study was to evaluate the prognostic value of submaximal or high exercise capacity stress echocardiography. We evaluated 1781 patients (55 ± 13 years; 59% male) undergoing treadmill stress echocardiography divided into 811 patients with submaximal (high exercise capacity (≥ 10 METS). Resting left ventricular ejection fraction and regional wall motion were assessed. The left ventricle was divided into 16 segments and scored on 5-point scale of wall motion. Abnormal stress echocardiography was defined as stress-induced ischemia (wall-motion score of ≥ 1 grade). Follow-up (3.3 ± 1.5 years) for nonfatal myocardial infarction (MI) (n = 40) and cardiac death (n = 52) were obtained. By univariate analysis, echocardiographic variables of ejection fraction, peak wall-motion score index (WMSI) and number of new ischemic wall-motion abnormalities were significant predictors of cardiac events. Cumulative survival was significantly worse in patients with abnormal (ischemic) versus normal (nonischemic) stress echocardiography in submaximal (4.4%/year vs. 1.3%/year, P high exercise capacity (1.5%/year vs. 0.2%/year, P high exercise capacity studies. © 2013, Wiley Periodicals, Inc.

  10. Jump ergometer in sport performance testing Výskokový ergometr v diagnostice sportovní výkonnosti

    Directory of Open Access Journals (Sweden)

    Dušan Hamar

    2005-02-01

    Full Text Available The papers deals with the application of the jump ergometer in the evaluation of neuromuscular performance. Altogether 288 athletes of different sport specializations (mean age 18.9 ± 6.4 years, height 172.2 ± 4.3 cm, and weight 62.4 ± 4.9 kg underwent various tests on the jump ergometer, such as 10-, 60-, and 90-second repeated jumps, squat and countermovement jumps without and with an additional load, and drop jumps from different heights with and without bending the knees. The diagnostic system FiTRO Jumper consisting of a special contact switch mattress connected by means of an interface to a computer was used. Jump parameters (power in the active phase of take off and height of the jump were calculated from the flight and contact times. Results showed that the system may be applied for the assessment of explosive power of the lower extremities, strength endurance of the lower extremities, utilization of the stretch shortening cycle, distribution of fast twitch fibers, optimal drop jump height for plyometric training, and training effects, namely in sports such as basketball, volleyball, soccer, tennis, gymnastics, rock and roll, figure skating, track and field, ski jumping, weight lifting, etc. Práce poukazuje na možnosti uplatnění výskokového ergometru při posuzovaní odrazových schopností dolních končetin. Celkem 288 sportovců s různou specializací (průměrný věk 18,9 ± 6,4 let, výška 172,2 ± 4,3 cm, hmotnost 62,4 ± 4,9 kg absolvovalo testy na výskokovém ergometru, a to 10, 60 a 90sekundový test opakovaných snožných výskoků, výskoky bez a s protipohybem s hmotností vlastního těla, resp. s dodatečnou váhou, jakož i seskoky z různych výšek do rovných, resp. pokrčených dolních končetin. Parametry odrazových schopností (výkon v aktivní fázi odrazu a výška výskoku byly registrovány pomocí diagnostického systému FiTRO Jumper sestávajícího z odrazové doby napojené prost

  11. Brief note about plasma catecholamines kinetics and submaximal exercise in untrained standardbreds

    Directory of Open Access Journals (Sweden)

    Paolo Baragli

    2010-03-01

    Full Text Available Four untrained standardbred horses performed a standardized exercise test on the treadmill and an automated blood collection system programmed to obtain blood samples every 15 s was used for blood collection in order to evaluate the kinetics of adrenaline and noradrenaline. The highest average values obtained for adrenaline and noradrenaline were 15.0 ± 3.0 and 15.8 ± 2.8 nmol/l respectively, with exponential accumulation of adrenaline (r = 0.977 and noradrenaline (r = 0.976 during the test. Analysis of the correlation between noradrenaline and adrenaline for each phase of the test shows that correlation coefficient decreases as the intensity of exercise increases (from r = 0.909 to r = 0.788. This suggests that during submaximal exercise, the process for release, distribution and clearance of adrenaline into blood circulation differs from that of noradrenaline.

  12. The validity of submaximal ratings of perceived exertion to predict one repetition maximum.

    Science.gov (United States)

    Eston, Roger; Evans, Harrison James Llewelyn

    2009-01-01

    The One Repetition Maximum (1-RM) test is commonly used to assess strength. However, direct assessments of 1-RM are time consuming and unsafe for novice lifters. Whilst various equations exist to predict 1-RM, there is limited research on the validity of these equations. The purpose of this study was to assess the validity of using sub-maximal ratings of perceived exertion (RPE) to predict 1-RM in young adults, using the Borg 6-20 RPE Scale. Twenty healthy participants (ten male (Mean ± SD, 20.8 ± 0.6 y, 75.7 ± 9.3 kg, 1.8 ± 0.07 m) and ten female (20.3 ± 0.7 y, 68.4 ± 10.0 kg, 1.68 ± 0.03 m)) completed two trials involving resistance exercises for both the upper and lower body. In the first trial the 1-RM for the bilateral biceps curl (BC) and the bilateral knee extension (KE) were determined for each participant. In the second trial, participants performed blinded repetitions which were equivalent to 20, 40 and 60 % of 1-RM for both exercises. The RPE was recorded immediately after two repetitions had been completed at each intensity. The order of intensity of the repetitions was randomly assigned with participants wearing blindfolds to exclude the possibility of pre-determined judgments about load and RPE. Individual RPE recorded at each intensity was subjected to linear regression analysis and the line of best fit was extrapolated to RPE 20 to predict 1-RM in both exercises. There was no significant difference (p > 0.05) between the 1-RM predicted from RPE 20 and measured 1-RM for both exercises for the men and women. Measured and predicted values for men were 46.0 ± 4.6 and 45.2 ± 6. 1 kg for biceps curl, and 46.3 ± 3.8 and 43.0 ± 7.1 kg for knee extension, respectively. Measured and predicted values for women were 18.6 ± 5.7 and 19.3 ± 5.6 kg for biceps curl, and 25.5 ± 9.6 and 27.2 ± 12.6 kg for knee extension, respectively. Pearson product-moment correlation coefficients between actual and predicted 1-RM for the BC and KE were 0.97 and 0

  13. Haemodynamic changes induced by submaximal exercise before a dive and its consequences on bubble formation

    Science.gov (United States)

    Blatteau, Jean‐Eric; Boussuges, Alain; Gempp, Emmanuel; Pontier, Jean‐Michel; Castagna, Olivier; Robinet, Claude; Galland, Francois‐Michel; Bourdon, Lionel

    2007-01-01

    Objectives To evaluate the effects of a submaximal exercise performed 2 h before a simulated dive on bubble formation and to observe the haemodynamic changes and their influence on bubble formation. Participants and methods 16 trained divers were compressed in a hyperbaric chamber to 400 kPa for 30 min and decompressed at a rate of 100 kPa/min with a 9 min stop at 130 kPa (French Navy MN90 procedure). Each diver performed two dives 3 days apart, one without exercise and one with exercise before the dive. All participants performed a 40 min constant‐load submaximal and calibrated exercise, which consisted of outdoor running 2 h before the dive. Circulating bubbles were detected with a precordial Doppler at 30, 60 and 90 min after surfacing. Haemodynamic changes were evaluated with Doppler echocardiography. Results A single bout of strenuous exercise 2 h before a simulated dive significantly reduced circulating bubbles. Post‐exercise hypotension (PEH) was observed after exercise with reductions in diastolic and mean blood pressure (DBP and MBP), but total peripheral resistance was unchanged. Stroke volume was reduced, whereas cardiac output was unchanged. Simulated diving caused a similar reduction in cardiac output independent of pre‐dive exercise, suggesting that pre‐dive exercise only changed DBP and MBP caused by reduced stroke volume. Conclusion A single bout of strenuous exercise 2 h before a dive significantly reduced the number of bubbles in the right heart of divers and protected them from decompression sickness. Declining stroke volume and moderate dehydration induced by a pre‐dive exercise might influence inert gas load and bubble formation. PMID:17138641

  14. Muscle vibration sustains motor unit firing rate during submaximal isometric fatigue in humans.

    Science.gov (United States)

    Griffin, L; Garland, S J; Ivanova, T; Gossen, E R

    2001-09-15

    1. In keeping with the 'muscular wisdom hypothesis', many studies have documented that the firing rate of the majority of motor units decreased during fatiguing isometric contractions. The present study investigated whether the application of periodic muscle vibration, which strongly activates muscle spindles, would alter the modulation of motor unit firing rate during submaximal fatiguing isometric contractions. 2. Thirty-three motor units from the lateral head of the triceps brachii muscle were recorded from 10 subjects during a sustained isometric 20 % maximal voluntary contraction (MVC) of the elbow extensors. Vibration was interposed on the contraction for 2 s every 10 s. Twenty-two motor units were recorded from the beginning of the fatigue task. The discharge rate of the majority of motor units remained constant (12/22) or increased (4/22) with fatigue. Six motor units demonstrated a reduction in discharge rate that later returned toward initial values; these motor units had higher initial discharge rates than the other 16 motor units. 3. In a second series of experiments, four subjects held a sustained isometric 20 % MVC for 2 min and then vibration was applied as above for the remainder of the contraction. In this case, motor units initially demonstrated a decrease in firing rate that increased after the vibration was applied. Thus muscle spindle disfacilitation of the motoneurone pool may be associated with the decline of motor unit discharge rate observed during the first 2 min of the contraction. 4. In a third set of experiments, seven subjects performed the main experiment on one occasion and repeated the fatigue task without vibration on a second occasion. Neither the endurance time of the fatiguing contraction nor the MVC torque following fatigue was affected by the application of vibration. This finding calls into question the applicability of the muscular wisdom hypothesis to submaximal contractions.

  15. Relationship between Force-Velocity Profiles and 1,500-m Ergometer Performance in Young Rowers.

    Science.gov (United States)

    Giroux, Caroline; Maciejewski, Hugo; Ben-Abdessamie, Amal; Chorin, Frédéric; Lardy, Julien; Ratel, Sebastien; Rahmani, Abderrahmane

    2017-11-01

    Rowing races require developing high level of force and power output at high contraction velocity. This study determined the force-velocity and power-velocity (F-P-V) profiles of lower and upper limbs of adolescent rowers and their relationships with a 1,500-m rowing ergometer performance. The power developed during the 1,500-m (P 1500 ) was evaluated in fourteen national-level male rowers (age: 15.3±0.6 yrs). F-P-V profiles were assessed during bench pull (BP) and squat jump (SJ) exercises. The theoretical maximal values of force (F 0 ), velocity (V 0 ), power output (P max ) and the F-V relationship slope (S FV ) were determined. The body mass (BM) influence on these relationships was considered using an allometric approach. F 0 was 720±144 and 2146±405 N, V 0 was 1.8±0.1 and 1.8±0.3 m·s -1 , P max was 333±83 and 968±204 W and S FV was -391±54 and -1,200±260 N·s·m -1 for BP and SJ, respectively. Upper and lower limb F 0 and P max were significantly related. P 1500 was significantly ( P V 0-BP , F 0-BP , S FV-BP , P max-BP , F 0-SJ and P max-SJ (r²=0.29 to 0.79). BM accounted for more than 90% of these relationships. Rowers' F-P-V profiles reflect adaptations to chronic rowing practice. F-P-V profiles and rowing performance correlations suggest that BP and SJ exercises are relevant to evaluate young rowers' explosive abilities. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Evaluation of respiratory dynamics by volumetric capnography during submaximal exercise protocol of six minutes on treadmill in cystic fibrosis patients.

    Science.gov (United States)

    Parazzi, Paloma L F; Marson, Fernando A L; Ribeiro, Maria A G O; Schivinski, Camila I S; Ribeiro, José D

    2017-11-29

    Volumetric capnography provides the standard CO2 elimination by the volume expired per respiratory cycle and is a measure to assess pulmonary involvement. Thus, the objective of this study was to evaluate the respiratory dynamics of healthy control subjects and those with cystic fibrosis in a submaximal exercise protocol for six minutes on the treadmill, using volumetric capnography parameters (slope 3 [Slp3], Slp3/tidal volume [Slp3/TV], and slope 2 [Slp2]). This was a cross-sectional study with 128 subjects (cystic fibrosis, 64 subjects; controls, 64 subjects]. Participants underwent volumetric capnography before, during, and after six minutes on the treadmill. Statistical analysis was performed using the Friedman, Mann-Whitney, and Kruskal-Wallis tests, considering age and sex. An alpha=0.05 was considered. Six minutes on the treadmill evaluation: in cystic fibrosis, volumetric capnography parameters were different before, during, and after six minutes on the treadmill; the same was observed for the controls, except for Slp2. Regarding age, an Slp3 difference was observed in cystic fibrosis patients regardless of age, at all moments, and in controls for age≥12 years; a difference in Slp3/TV was observed in cystic fibrosis and controls, regardless of age; and an Slp2 difference in the cystic fibrosis, regardless of age. Regarding sex, Slp3 and Slp3/TV differences were observed in cystic fibrosis regardless of sex, and in controls in male participants; an Slp2 difference was observed in the cystic fibrosis and female participants. The analysis between groups (cystic fibrosis and controls) indicated that Slp3 and Slp3/TV has identified the CF, regardless of age and sex, while the Slp2 showed the CF considering age. Cystic fibrosis showed greater values of the parameters before, during, and after exercise, even when stratified by age and sex, which may indicate ventilation inhomogeneity in the peripheral pathways in the cystic fibrosis. Copyright © 2017 Sociedade

  17. Exercise responses during functional electrical stimulation cycling in individuals with spinal cord injury.

    Science.gov (United States)

    Hasnan, Nazirah; Ektas, Nalan; Tanhoffer, Aldre Izabel P; Tanhoffer, Ricardo; Fornusek, Che; Middleton, James W; Husain, Ruby; Davis, Glen M

    2013-06-01

    This study compared acute exercise responses during arm cranking, functional electrical stimulation (FES)-assisted leg cycling, and combined arm and leg ("hybrid") cycling in individuals with spinal cord injury during maximal and submaximal exercise. Nine male subjects with long-standing neurological lesions from C7 to T12 were recruited. All subjects performed arm crank ergometry (ACE), FES leg cycle exercise (FES-LCE), combined ACE + FES-LCE, and cycling on a hybrid FES tricycle (HYBRID). They were assessed for their peak exercise responses in all four modalities. Subsequently, their submaximal heart rates (HR), cardiac outputs (Q), stroke volumes (SV), and arteriovenous oxygen extractions (Ca-Cv)O2 were measured at 40%, 60%, and 80% of mode-specific V˙O2peak. Arm exercise alone and arm + leg exercise resulted in significantly higher V˙O2peak and HRpeak compared with FES-LCE (P spinal cord injury population.

  18. THE VALIDITY OF SUBMAXIMAL RATINGS OF PERCEIVED EXERTION TO PREDICT ONE REPETITION MAXIMUM

    Directory of Open Access Journals (Sweden)

    Harrison James Llewelyn Evans

    2009-12-01

    Full Text Available The One Repetition Maximum (1-RM test is commonly used to assess strength. However, direct assessments of 1-RM are time consuming and unsafe for novice lifters. Whilst various equations exist to predict 1-RM, there is limited research on the validity of these equations. The purpose of this study was to assess the validity of using sub-maximal ratings of perceived exertion (RPE to predict 1-RM in young adults, using the Borg 6-20 RPE Scale. Twenty healthy participants (ten male (Mean ± SD, 20.8 ± 0.6 y, 75.7 ± 9.3 kg, 1.8 ± 0.07 m and ten female (20.3 ± 0.7 y, 68.4 ± 10.0 kg, 1.68 ± 0.03 m completed two trials involving resistance exercises for both the upper and lower body. In the first trial the 1-RM for the bilateral biceps curl (BC and the bilateral knee extension (KE were determined for each participant. In the second trial, participants performed blinded repetitions which were equivalent to 20, 40 and 60 % of 1-RM for both exercises. The RPE was recorded immediately after two repetitions had been completed at each intensity. The order of intensity of the repetitions was randomly assigned with participants wearing blindfolds to exclude the possibility of pre-determined judgments about load and RPE. Individual RPE recorded at each intensity was subjected to linear regression analysis and the line of best fit was extrapolated to RPE 20 to predict 1-RM in both exercises. There was no significant difference (p > 0.05 between the 1-RM predicted from RPE 20 and measured 1-RM for both exercises for the men and women. Measured and predicted values for men were 46.0 ± 4.6 and 45.2 ± 6. 1 kg for biceps curl, and 46.3 ± 3.8 and 43.0 ± 7.1 kg for knee extension, respectively. Measured and predicted values for women were 18.6 ± 5.7 and 19.3 ± 5.6 kg for biceps curl, and 25.5 ± 9.6 and 27.2 ± 12.6 kg for knee extension, respectively. Pearson product-moment correlation coefficients between actual and predicted 1-RM for the BC and KE were 0

  19. Several submaximal exercise tests are reliable, valid and acceptable in people with chronic pain, fibromyalgia or chronic fatigue: a systematic review

    Directory of Open Access Journals (Sweden)

    Julia Ratter

    2014-09-01

    [Ratter J, Radlinger L, Lucas C (2014 Several submaximal exercise tests are reliable, valid and acceptable in people with chronic pain, fibromyalgia or chronic fatigue: a systematic review. Journal of Physiotherapy 60: 144–150

  20. Evaluation of Exercise Response in a Young, High Risk Population: Submaximal Invasive Cardiopulmonary Exercise Testing (ICPET) in Active Duty Soldiers

    Science.gov (United States)

    2017-03-17

    Submaximal Invasive Cardiopulmonary Exercise Testing iCPET in AD Soldiers presented at/published to American College of Cardiology’s 661h Annual...disclaimer statement for research involving animals . as required by AFMAN 40-401 IP : " The experiments reported herein were conducted according to the...principles set forth in the National Institute of Health Publication No. 80-23, Guide for the Care and Use of Laboratory Animals and the Animal

  1. Application of "living high-training low" enhances cardiac function and skeletal muscle oxygenation during submaximal exercises in athletes.

    Science.gov (United States)

    Park, Hun-Young; Nam, Sang-Seok

    2017-03-31

    The aim of this study was to determine the efficiency of the application of living high-training low (LHTL) on cardiac function and skeletal muscle oxygenation during submaximal exercises compared with that of living low-training low (LLTL) in athletes. Male middle- and long-distance runners (n = 20) were randomly assigned into the LLTL group (n = 10, living at 1000-m altitude and training at 700-1330-m altitude) and the LHTL group (n = 10, living at simulated 3000-m altitude and training at 700-1330-m altitude). Their cardiac function and skeletal muscle oxygenation during submaximal exercises at sea level before and after training at each environmental condition were evaluated. There was a significant interaction only in the stroke volume (SV); however, the heart rate (HR), end-diastolic volume (EDV), and end-systolic volume (ESV) showed significant main effects within time; HR and SV significantly increased during training in the LHTL group compared with those in the LLTL group. EDV also significantly increased during training in both groups; however, the LHTL group had a higher increase than the LLTL group. ESV significantly increased during training in the LLTL group. There was no significant difference in the ejection fraction and cardiac output. The skeletal muscle oxygen profiles had no significant differences but improved in the LHTL group compared with those in the LLTL group. LHTL can yield favorable effects on cardiac function by improving the HR, SV, EDV, and ESV during submaximal exercises compared with LLTL in athletes.

  2. Reduced peripheral arterial blood flow with preserved cardiac output during submaximal bicycle exercise in elderly heart failure

    Directory of Open Access Journals (Sweden)

    Leng Xiaoyan

    2009-11-01

    Full Text Available Abstract Background Older heart failure (HF patients exhibit exercise intolerance during activities of daily living. We hypothesized that reduced lower extremity blood flow (LBF due to reduced forward cardiac output would contribute to submaximal exercise intolerance in older HF patients. Methods and Results Twelve HF patients both with preserved and reduced left ventricular ejection fraction (LVEF (aged 68 ± 10 years without large (aorta or medium sized (iliac or femoral artery vessel atherosclerosis, and 13 age and gender matched healthy volunteers underwent a sophisticated battery of assessments including a peak exercise oxygen consumption (peak VO2, b physical function, c cardiovascular magnetic resonance (CMR submaximal exercise measures of aortic and femoral arterial blood flow, and d determination of thigh muscle area. Peak VO2 was reduced in HF subjects (14 ± 3 ml/kg/min compared to healthy elderly subjects (20 ± 6 ml/kg/min (p = 0.01. Four-meter walk speed was 1.35 ± 0.24 m/sec in healthy elderly verses 0.98 ± 0.15 m/sec in HF subjects (p p ≤ 0.03. Conclusion During CMR submaximal bike exercise in the elderly with heart failure, mechanisms other than low cardiac output are responsible for reduced lower extremity blood flow.

  3. Effects of Submaximal Endurance Training and Vitamin D3 Supplementation on Pain Threshold in Diabetic Rats

    Directory of Open Access Journals (Sweden)

    S. Jalal Taherabadi

    2013-07-01

    Full Text Available Background: According to beneficial effects of endurance training and vitamin D3 in diabetes mellitus, purpose of this study is effects submaximal endurance training and vitamin D3 supplementation on pain threshold in streptozotocin induced diabetic rats.Materials and Methods: Male Wistar rats (250±20 g, N=40 were made diabetic by streptozotocin (60 mg/kg, subcutaneously. 72 h after injection diabetes induction was confirmed by tail vein blood glucose concentration (>300 mg/dl. Then animals were divided to five groups: diabetic control (DC, diabetic trained (DT, diabetic -vitamin D (DD, diabetic trained and vitamin D (DTD, and control (C. Animals were submitted to endurance training by treadmill and vitamin D3 treatment (twice aweek, intrapretonally for 4 weeks. 48 h after at the end of exercise and treatment protocol, we used tail-flick to assess the effects of training and vitamin D3 on thermal pain threshold. We used one way ANOVA statistical analysis to compare differences between groups, significance level of p<0.05 was considered.Results: Diabetic induced hyperalgesia were decreased significantly by vitamin D but not 4 weeks endurance exercise training. Concurrent effects of training and vitamin D on thermal pain threshold were not significantly higher than vitamin D effects alone.Conclusion: It is concluded that vitamin D administration given at the time of diabetes induction may be able to restore thermal hyperalgesia. But effects of endurance exercise training needs to more investigation in diabetic rats.

  4. Predictability of maximum voluntary isometric knee extension force from submaximal contractions in older adults.

    Science.gov (United States)

    Stackhouse, Scott K; Stevens, Jennifer E; Johnson, Christopher D; Snyder-Mackler, Lynn; Binder-Macleod, Stuart A

    2003-01-01

    The purposes of this study were to develop and test a model describing the relationship between the central activation ratio (CAR; a measure of voluntary muscle activation) and percent maximum voluntary contraction (%MVC) force for old adults and to provide a method for more accurate determination of voluntary muscle activation failure. Twenty-one adults (ages 64-81) performed isometric testing of the quadriceps at 25%, 50%, 75%, and 100% MVC. During each contraction, a 100-HZ, 120-ms train of electrical pulses was delivered to the quadriceps muscle to quantify voluntary muscle activation. Similar to a young, healthy population (ages 20-35), a curvilinear relationship existed between the CAR and %MVC force for older adults. Predictions of subjects' MVCs using the linear model of CAR-%MVC force relationship generally demonstrated poor agreement with actual MVCs. Predictions of MVC from submaximal contractions (25%, 50%, and 75%) using a previously identified curvilinear young adult CAR-%MVC relationship were good [ICC (2,1): 0.81, 0.96, and 0.82, respectively]. Similar agreement was obtained from the curvilinear older adult CAR-%MVC relationship. These data suggest that the CAR-%MVC relationship is similar in young and older adult subjects and that curvilinear models of this relationship can predict MVC forces in older adults more accurately. Reexamination of the relationship between the CAR and %MVC force may allow a more accurate determination of how failure of voluntary muscle activation contributes to weakness in old adults.

  5. Is the ventilatory threshold coincident with maximal fat oxidation during submaximal exercise in women?

    Science.gov (United States)

    Astorino, T A

    2000-09-01

    The purpose of this study was to detect the fraction of peak oxygen consumption (VO2peak) that elicits maximal rates of fat oxidation during submaximal treadmill exercise. It was hypothesized that this point would appear at a work rate just below the ventilatory threshold. subjects completed a protocol requiring them to exercise for 15 min on a treadmill at six different workloads, 25, 40, 55, 65, 75, and 85% VO2peak, over two separate visits. nine healthy, moderately-trained eumenorrheic females (age = 28.8+/-5.99 yrs, VO2peak = 47.20 +/-2.57 ml x kg(-1) x min(-1)) volunteered for the study. a one-way ANOVA with repeated measures was used to test for differences across exercise intensities in the metabolic variables (i.e. substrate oxidation, blood lactate concentration ([La-]), RER, and the contribution of fat to total energy expenditure). Following significant F ratios, post-hoc tests were used to detect differences between the means for various exercise intensities. Exercise at 75% VO2peak elicited the greatest rate of fat oxidation (4.75+/-0.49 kcal x min(-1)), and this intensity was coincident with the ventilatory threshold (76+/-7.41% VO2peak). Moreover, a significant difference (t(8) = -3.98, ppopulation has application in exercise prescription and refutes the belief that low-intensity exercise is preferred for fat metabolism.

  6. A macro-driven Excel template for determining the anaerobic capacity using an air-braked ergometer.

    Science.gov (United States)

    Finn, J P; Sainsbury, D A; Withers, R T

    1996-08-01

    This paper describes a microcomputer system for automating the process of data collection, calculation and display of anaerobic capacity tests on an air-braked ergometer. The use of the spreadsheet Excel and associated 'Dalog' program represents an advance on current software which estimates the anaerobic capacity from work performed alone. Numerous calculations are required when air-braked, rather than friction-braked erogometers are used. Each 1 s power output collected during an all-out sprint on the ergometer is corrected against the criterion of a dynamic calibration rig and adjusted for differences in barometric pressure, ambient temperature and humidity. The Excel template features a series of macros invoked by buttons imbedded in the spreadsheet. Their selection displays various dialogue boxes which request input related to the calculation of oxygen deficit and related variables. Selecting the final macro prints a summary table and charts which include: power output, fatigue index, mechanical work performed, % aerobic contribution to work, oxygen demand, oxygen consumption and anaerobic capacity as determined by the maximal accumulated oxygen deficit.

  7. Inflight Exercise Regimen for the 2-Hour Prebreathe Protocol

    Science.gov (United States)

    Foster, Philip P.; Gernhardt, Michael L.; Woodruff, Kristin K.; Schneider, Susan M.; Homick, Jerry L. (Technical Monitor)

    2000-01-01

    A 10 min aerobic prebreathe exercise up to 75% V-O2(sub max) on a dual-cycle ergometer, included in the 2-hour prebreathe protocol, has been shown to dramatically reduce the incidence of decompression sickness (DCS) at altitude. In-flight only leg ergometry will be available. A balanced exercise was developed using surgical tubing with the ergometer on-orbit. We hypothesize that a 75% V02max workload, individually prescribed, would be achieved using a target heart rate to regulate the intensity of the arm exercise. VO2, heart rate (HR) / ECG, V-CO2 /V-O2, V(sub E), and V(sub T), and rate of perceived exertion (Borg scale) were measured in eleven healthy subjects who passed a US Air Force Class III Physical examination. A V-O2 peak test was performed to assess the sub-maximal exercise prescription. Two series of sub-maximal tests were performed: (1) leg ergometer/hand ergometer and (2) leg ergometer/surgical tubes. We found no significant differences (P > 0.05) in comparing the means for V-O2 and HR between the predicted and measured values during the final 4 minute-stage at "75% V-O2 workload" or between the two types of sub-maximal tests. The prescribed prebreathe sub-maximal exercise performed with flight certified surgical tubes was achieved using the target HR.

  8. Intra-limb coordinative adaptations in cycling.

    Science.gov (United States)

    Sides, Deborah; Wilson, Cassie

    2012-03-01

    This study aimed to establish the nature of lower extremity intra-limb coordination variability in cycling and to investigate the coordinative adaptations that occur in response to changes in cadence and work rate. Six trained and six untrained males performed nine pedalling bouts on a cycle ergometer at various cadences and work rates (60, 90, and 120 revolutions per minute (rpm) at 120, 210, and 300W). Three-dimensional kinematic data were collected and flexion/extension angles of the ankle, knee, and hip joints were subsequently calculated. These data were used to determine two intra-limb joint couplings [hip flexion/extension-knee flexion/extension (HK) and knee flexion/extension-ankle plantar-flexion/dorsi-flexion (KA)], which were analysed using continuous relative phase analysis. Trained participants displayed significantly (p cycling is necessary before any recommendations can be made.

  9. Acute Warm-up Effects in Submaximal Athletes: An EMG Study of Skilled Violinists.

    Science.gov (United States)

    McCrary, J Matt; Halaki, Mark; Sorkin, Evgeny; Ackermann, Bronwen J

    2016-02-01

    Warm-up is commonly recommended for injury prevention and performance enhancement across all activities, yet this recommendation is not supported by evidence for repetitive submaximal activities such as instrumental music performance. The objective of this study is to quantify the effects of cardiovascular, core muscle, and musical warm-ups on muscle activity levels, musical performance, and subjective experience in skilled violinists. Fifty-five undergraduate, postgraduate, or professional violinists performed five randomly ordered 45-s musical excerpts of varying physical demands both before and after a randomly assigned 15-min, moderate-intensity cardiovascular, core muscle, musical (technical violin exercises), or inactive control warm-up protocol. Surface EMG data were obtained for 16 muscles of the trunk, shoulders, and right arm during each musical performance. Sound recording and perceived exertion (RPE) data were also obtained. Sound recordings were randomly ordered and rated for performance quality by blinded adjudicators. Questionnaire data regarding participant pain sites and fitness levels were used to stratify participants according to pain and fitness levels. Data were analyzed using two- and three-factor ANCOVA (surface EMG and sound recording) and Wilcoxon matched pairs tests (RPE). None of the three warm-up protocols had significant effects on muscle activity levels (P ≥ 0.10). Performance quality did not significantly increase (P ≥ 0.21). RPE significantly decreased (P 0.23). Acute physiological and musical benefits from cardiovascular, core muscle, and musical warm-ups in skilled violinists are limited to decreases in RPE. This investigation provides data from the performing arts in support of sports medical evidence suggesting that warm-up only effectively enhances maximal strength and power performance.

  10. Cortical and spinal mechanisms of task failure of sustained submaximal fatiguing contractions.

    Directory of Open Access Journals (Sweden)

    Petra S Williams

    Full Text Available In this and the subsequent companion paper, results are presented that collectively seek to delineate the contribution that supraspinal circuits have in determining the time to task failure (TTF of sustained submaximal contractions. The purpose of this study was to compare adjustments in supraspinal and spinal excitability taken concurrently throughout the performance of two different fatigue tasks with identical mechanical demands but different TTF (i.e., force-matching and position-matching tasks. On separate visits, ten healthy volunteers performed the force-matching or position-matching task at 15% of maximum strength with the elbow flexors to task failure. Single-pulse transcranial magnetic stimulation (TMS, paired-pulse TMS, paired cortico-cervicomedullary stimulation, and brachial plexus electrical stimulation were delivered in a 6-stimuli sequence at baseline and every 2-3 minutes throughout fatigue-task performance. Contrary to expectations, the force-matching task TTF was 42% shorter (17.5 ± 7.9 min than the position-matching task (26.9 ± 15.11 min; p0.05. Therefore, failure occurred after a similar mean decline in motorneuron excitability developed (p0.10 and an index of upstream excitation of the motor cortex remained constant (p>0.40. Together, these results suggest that as fatigue develops prior to task failure, the increase in corticospinal excitability observed in relationship to the decrease in spinal excitability results from a combination of decreasing intracortical inhibition with constant levels of intracortical facilitation and upstream excitability that together eventually fail to provide the input to the motor cortex necessary for descending drive to overcome the spinal cord resistance, thereby contributing to task failure.

  11. Cortical and Spinal Mechanisms of Task Failure of Sustained Submaximal Fatiguing Contractions

    Science.gov (United States)

    Williams, Petra S.; Hoffman, Richard L.; Clark, Brian C.

    2014-01-01

    In this and the subsequent companion paper, results are presented that collectively seek to delineate the contribution that supraspinal circuits have in determining the time to task failure (TTF) of sustained submaximal contractions. The purpose of this study was to compare adjustments in supraspinal and spinal excitability taken concurrently throughout the performance of two different fatigue tasks with identical mechanical demands but different TTF (i.e., force-matching and position-matching tasks). On separate visits, ten healthy volunteers performed the force-matching or position-matching task at 15% of maximum strength with the elbow flexors to task failure. Single-pulse transcranial magnetic stimulation (TMS), paired-pulse TMS, paired cortico-cervicomedullary stimulation, and brachial plexus electrical stimulation were delivered in a 6-stimuli sequence at baseline and every 2–3 minutes throughout fatigue-task performance. Contrary to expectations, the force-matching task TTF was 42% shorter (17.5±7.9 min) than the position-matching task (26.9±15.11 min; pmuscle fatigue (p = 0.59). There were no task-specific differences for the total amount or rate of change in the neurophysiologic outcome variables over time (p>0.05). Therefore, failure occurred after a similar mean decline in motorneuron excitability developed (p0.10) and an index of upstream excitation of the motor cortex remained constant (p>0.40). Together, these results suggest that as fatigue develops prior to task failure, the increase in corticospinal excitability observed in relationship to the decrease in spinal excitability results from a combination of decreasing intracortical inhibition with constant levels of intracortical facilitation and upstream excitability that together eventually fail to provide the input to the motor cortex necessary for descending drive to overcome the spinal cord resistance, thereby contributing to task failure. PMID:24667484

  12. TEST-RETEST RELIABILITY OF THE AEROBIC POWER INDEX SUBMAXIMAL EXERCISE TEST IN CANCER PATIENTS

    Directory of Open Access Journals (Sweden)

    Bonnie J. Furzer

    2012-12-01

    Full Text Available The purpose of this study was to investigate the reliability of the Aerobic Power Index (API submaximal cardiorespiratory exercise test, as well as associated variables of oxygen uptake (ml·kg-1·min-1 and ratings of perceived exertion (RPE in cancer patients who are generally unable to complete maximal or lengthy aerobic fitness tests. Twenty male and female participants (11 male; 9 female aged between 18 and 70 y (mean = 53.28 ± 11. 82 y were recruited with medical consent within 4 weeks of completing chemotherapy treatment for a lymphohaematopoietic cancer (LHC. Of the twenty recruited participants' 2 were excluded from analysis due to disease relapse or complications unrelated to testing occurring within the month following testing. Intra-class correlation coefficient (ICC scores for power output (W·kg-1 and oxygen uptake (ml·kg-1·min-1 were highly reliable (R1 = 0.96 and 0.96, respectively and the ICC for RPE was moderately reliable (R1 = 0.83. Technical error of measurement results for power output (W·kg-1, oxygen uptake (ml·kg-1·min-1 and RPE were 0.11W·kg-1, 1.18 ml·kg-1·min-1 and 1.0 respectively. A Pearson's product-moment correlation demonstrated a strong relationship between power output (W·kg-1 and oxygen uptake (ml·kg-1·min-1 for both trials (r = 0.93 and 0.89, respectively. Results demonstrate that the API test is a highly reliable protocol for use with a LHC population and can be considered a clinically feasible, safe and tolerable exercise test

  13. A submaximal test for the assessment of knee extensor endurance capacity.

    Science.gov (United States)

    De Ruiter, Cornelis J; Mallee, Max I P; Leloup, Lara E C; De Haan, Arnold

    2014-02-01

    We aimed to develop an undemanding test for endurance capacity of the knee extensor muscles, which can also be applied to frail participants. We hypothesized 1) that the first objective indications for peripheral fatigue during incremental unilateral repetitive isometric knee extensor contractions could be used to assess a fatigue threshold (FT), 2) that torque at FT would depend on training status, and 3) that this torque could easily be sustained for 30 min. Five trained and five untrained participants performed 5-min bouts of 60 repetitive contractions (3-s on and 2-s off). Torque, set at 25% maximal voluntary contraction (MVC), was increased by 5% MVC in subsequent bouts. The highest torque for which rectified surface EMG remained stable during the bout was defined as the FT. On separate occasions, 30-min bouts were performed at and above the FT to assess sustainable torque. Changes in gas exchange parameters, HR, and RPE were monitored to corroborate FT. At FT (RPE = 5.7 ± 1.7), torque was higher (P MVC) than in untrained participants (30.5% ± 1.8% MVC). Sustainable torque was ∼4% higher than (P MVC, significant increases in rectified surface EMG and V˙O2 were found. During incremental knee extensor contractions, FT could be assessed at a submaximal exercise intensity. FT was higher in trained than in untrained participants and was related to exercise sustainability. With the use of FT, changes in endurance capacity of single muscle groups can potentially also be determined in frail participants for whom exercise performed until exhaustion is unwarranted.

  14. The Effect of Acute Sub-Maximal Endurance Exercise on Serum Angiogenic Indices in Sedentary Men

    Directory of Open Access Journals (Sweden)

    Kamal Ranjbar

    2014-06-01

    Full Text Available Background: Endurance training increases capillary density of skeletal muscle, but the molecular mechanism of this process is not yet clear. Therefore, the purpose of this study was to investigate the effect of acute sub maximal endurance exercise on serum levels of vascular endothelial growth factor (VEGF and matrix metaloproteinases 2 and 9 (MMP-2 and MMP-9 in sedentary men. Materials and Methods: Twelve healthy men (22.37±2.30 years, BMI=23.16 ±2.61 kg/mP 2 P participated in this study. Subjects exercised for 1h at 70% of VOR2R max, 3 days after the VOR2R max determination. Antecubital vein blood was collected at rest, immediately and 2h after the exercise. Serum VEGF, MMP-2 and MMP-9 were measured by ELISA methods5T. Results: Serum levels of VEGF and MMP-2 decreased immediately after the exercise. 2 hours after the exercise, serum levels of VEGF remained at a lower level but serum MMP-2 returned to its basal level. Also, serum levels of MMP-9 did not change significantly in response to exercise5T. Conclusion: Acute sub-maximal endurance exercise decreased the main factors involved in development of capillary density in sedentary men. This might to due to the fact that, sub maximal exercise could not provide the two main stimulating factors of angiogenesis, i.e. Shear stress and hypoxia. It could also be explained by the fact that the mechanism of development of capillary network following regular endurance training is different from that following an acute exercise5T.5T

  15. A Systematic Review and Meta-analysis Comparing Cardiopulmonary Exercise Test Values Obtained From the Arm Cycle and the Leg Cycle Respectively in Healthy Adults

    DEFF Research Database (Denmark)

    Larsen, Rasmus Tolstrup; Christensen, Jan; Tang, Lars Hermann

    2016-01-01

    INTRODUCTION: The cardiopulmonary exercise test (CPET) assesses maximal oxygen uptake (VO2max) and is commonly performed on a leg cycle ergometer (LC). However, some individuals would rather perform the CPET on an arm cycle ergometer (AC). OBJECTIVE: The objectives of this study were to undertake...... a systematic review and meta-analysis of the difference in VO2max achieved by AC compared to LC in healthy adults and to explore factors that may be predictive of this difference. METHODS: MEDLINE, EMBASE, CINAHL, and PEDro were searched in April 2015. The differences in VO2max (ACLCdiff) were pooled across...... studies using random effects meta-analysis and three different methods were used to estimate the ratio between the values obtained from the tests (ACLCratio). RESULTS: This paper included 41 studies with a total of 581 participants. The mean ACLCdiff across studies was 12.5 ml/kg/min and 0.89 l...

  16. Plasma growth hormone, cortisol and testosterone responses to repeated and intermittent ergometer exercise at different pedalling rates.

    Directory of Open Access Journals (Sweden)

    BH Opaszowski

    2003-06-01

    Full Text Available The aim of this work was the evaluation of the hormonal response to the repeated and intermittent exercises at different rates. Nine students of the physical education (age: 24.1±0.39 years; body mass: 81.2±10.17kg; height: 182.1±7.32 cm; VO2max – 4.121±0.697 l O2/min performed in the laboratory conditions series of 5 efforts on the cycle ergometer lasting for 3 min with the loading of 250 W and divided with 2 min intervals. In the first day the pedalling rate amounted to 45circ/min (W45, in the second day to 80circ/min (W80. In both cases the work performed (225 kJ, time lasting and power of efforts were the same. The growth hormone (GH, testosterone (T and cortisol (C were denoted in the capillary blood taken with the immuno-enzymatic methods from the finger tip. The anabolic – catabolic index (T/C was also determined. The blood acid – alkali balance parameters were registered using the gas analyser Ciba-Corning 248. The blood was taken: before effort, after third effort (13 min, immediately after fifth effort (23 min and 30 min after the test. Series of the repeated and intermittent exercises caused the significant (P<0.05 lowering of the capillary blood pH, respectively from: 7.392–7.409 before effort to: 7.316±0.092 (W45 and 7.287±0.068 (W80 after fifth effort. The differences between W45 and W80 were statistically insignificant. The highest concentrations of GH and T were noticed after all efforts in both series. The T concentration grew significantly, similarly in both series: W45 –5.8±1.93 and W80 –5.9±1.59 ng/ml from the restful level ≈ 4.6 ng/ml. The significant differentiation of the response on different pedalling rates was observed in case of GH. The highest GH concentration amounted to: 7.7±5.43 ng/ml after W45 and after W80 to: 16.8±6.68 ng/ml. The GH concentration changes presented lower level (P<0.05 during work performed with the smaller rate i.e.: 45circ/min. As regards cortisol (C, the significant

  17. The ankle ergometer: A new tool for quantifying changes in mechanical properties of human muscle as a result of spaceflight

    Science.gov (United States)

    Mainar, A.; Vanhoutte, C.; Pérot, C.; Voronine, L.; Goubel, F.

    A mechanical device for studying changes in mechanical properties of human muscle as a result of spaceflight is presented. Its main capacities are to allow during a given experiment investigation of both contractile and visco-elastic properties of a musculo-articular complex using respectively isometric contractions, isokinetic movements, quick-release tests and sinusoidal perturbations. This device is a motor driven ergometer associated to an experimental protocol designed for pre- and post-flight experiments. As microgravity preferentially affects postural muscles, the apparatus was designed to test muscle groups crossing the ankle joint. Three subjects were tested during the Euromir '94 mission. Preliminary results obtained on the european astronaut are briefly reported. During the next two years the experiments will be performed during six missions.

  18. Comparison of step-wise and ramp-wise incremental rowing exercise tests and 2000-m rowing ergometer performance.

    Science.gov (United States)

    Ingham, Stephen A; Pringle, Jamie S; Hardman, Sarah L; Fudge, Barry W; Richmond, Victoria L

    2013-03-01

    This study examined parameters derived from both an incremental step-wise and a ramp-wise graded rowing exercise test in relation to rowing performance. Discontinuous step-wise incremental rowing to exhaustion established lactate threshold (LT), maximum oxygen consumption (VO(2maxSTEP)), and power associated with VO(2max) (W VO(2max)). A further continuous ramp-wise test was undertaken to derive ventilatory threshold (VT), maximum oxygen consumption (VO(2maxRAMP)), and maximum minute power (MMW). Results were compared with maximal 2000-m ergometer time-trial power. The strongest correlation with 2000-m power was observed for MMW (r = .98, P rowing performance and thus may have potential as an influential monitoring tool for rowing athletes.

  19. Step Ergometer Training Augmented With Functional Electrical Stimulation in Individuals With Chronic Spinal Cord Injury: A Feasibility Study.

    Science.gov (United States)

    Tefertiller, Candy; Gerber, Don

    2017-11-01

    Spinal cord injury (SCI) often results in loss of upright mobility and independence subsequently challenging rehabilitation practitioners for meaningful intervention strategies. The objective of this study was to evaluate the feasibility and potential impact on walking function of the stimulation and ergometer training protocol (STEP) in chronic SCI. Fourteen individuals with a chronic motor incomplete SCI (>1-year post injury) were enrolled in the study. The intervention consisted of a 12-week walking training program delivered three times per week from 20 up to 45 min in combination with 10 channels of FES on a step ergometer. Subsequent to this training, 30 min over ground walking training was performed. Ten out of the 14 participants completed the trial (71%). All participants who completed the intervention increased their walking speed by an average of 0.13 m/s (0.08) and walking endurance by an average of 117 ft (84 ft). For those who completed the trial, 50% demonstrated increases on the Walking Index for Spinal Cord Injury II by at least one level while 60% demonstrated an increase in lower extremity motor scores; all completing the Timed Up and Go Test at baseline demonstrated a reduction in time to complete during post-test evaluation. Recruitment objectives were attained. Overall retention was lower than anticipated with 29% withdrawing secondary to issues with lower extremity pain and exertional demands; however, no other adverse events occurred. Improvements in mobility outcomes generated by the STEP show promise in the context of feasibility and warrant further investigation to evaluate efficacy in comparison to other walking recovery interventions. The STEP was well-tolerated by participants who were >1 year and less than 10 years post SCI. Those completing the protocol exhibited improvements in commonly used SCI walking outcome measures. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  20. Does a bout of strength training affect 2,000 m rowing ergometer performance and rowing-specific maximal power 24 h later?

    Science.gov (United States)

    Gee, Thomas I; French, Duncan N; Howatson, Glyn; Payton, Stephen J; Berger, Nicolas J; Thompson, Kevin G

    2011-11-01

    Rowers regularly undertake rowing training within 24 h of performing bouts of strength training; however, the effect of this practice has not been investigated. This study evaluated the impact of a bout of high-intensity strength training on 2,000 m rowing ergometer performance and rowing-specific maximal power. Eight highly trained male club rowers performed baseline measures of five separate, static squat jumps (SSJ) and countermovement jumps (CMJ), maximal rowing ergometer power strokes (PS) and a single 2,000 m rowing ergometer test (2,000 m). Subsequently, participants performed a high-intensity strength training session consisting of various multi-joint barbell exercises. The 2,000 m test was repeated at 24 and 48 h post-ST, in addition SSJ, CMJ and PS tests were performed at these time points and also at 2 h post-ST. Muscle soreness, serum creatine kinase (CK) and lactate dehydrogenase (LDH) were assessed pre-ST and 2, 24 and 48 h post-ST. Following the ST, there were significant elevations in muscle soreness (2 and 24 h, P rowing-specific maximal power, but this did not affect 2,000 m rowing ergometer performance in highly trained rowers.

  1. Comparação entre ergômetros específico e convencionais na determinação da capacidade aeróbia de mesatenistas Comparison between specific and conventional ergometers in the aerobic capacity determination in table tennis players

    Directory of Open Access Journals (Sweden)

    Alessandro Moura Zagatto

    2009-06-01

    Full Text Available O objetivo deste estudo foi verificar a necessidade de utilizar protocolo específico para avaliar a capacidade aeróbia de mesatenistas, comparando os testes aplicados em ergômetro específico com ergômetros convencionais. Para isso, nove mesatenistas foram os participantes do estudo (18,22 ± 2,33 anos; altura de 1,76 ± 0,09m; massa corporal de 67,36 ± 10,03kg; gordura corporal de 14,74 ± 6,69%; e índice de massa corporal (IMC de 21,69 ± 2,71kg/m². Foram aplicados os testes de lactato mínimo, realizados no ergômetro de braço (LACmin braço e no cicloergômetro (LACmin ciclo (ergômetros convencionais e o teste de limiar anaeróbio em procedimento específico para o tênis de mesa (LAn espec utilizando um lançador de bolas mecânico como ergômetro. Como procedimentos estatísticos foram utilizados o teste de análise de variância (ANOVA one way e o teste de correlação produto-momento, com nível de significância de 5%. O LAn espec (48,11 ± 6,82 bolas.min-1 não foi significativamente correlacionado com a intensidade de LACmin braço (91,94 ± 11,51W (r = 0,18; p = 0,72; e apresentou correlação negativa com a intensidade de LACmin ciclo (157,97 ± 12,51W (r = - 0,80; p = 0,02. Desse modo, os resultados encontrados no estudo levam a concluir que existe necessidade do uso de protocolo específico para mensurar a capacidade aeróbia no tênis de mesa.The aim of this study was to verify the necessity to use a specific protocol for evaluating the aerobic capacity in table tennis players, comparing the tests applied in conventional ergometers with test applied in specific ergometer. Nine table tennis players were participants in the study (18.22 ± 2.33 years; 1.76 ± 0.09 m of height; 67.36 ± 10.03 Kg of body mass; 14.74 ± 6.69 % of fat mass and 21.69 ± 2.71 Kg/m² of body mass index. The participants performed lactate minimum tests in the arm ergometer and cycle ergometer; in addition to incremental test in specific ergometer

  2. Different types of compression clothing do not increase sub-maximal and maximal endurance performance in well-trained athletes.

    Science.gov (United States)

    Sperlich, Billy; Haegele, Matthias; Achtzehn, Silvia; Linville, John; Holmberg, Hans-Christer; Mester, Joachim

    2010-04-01

    Three textiles with increasing compressive surface were compared with non-compressive conventional clothing on physiological and perceptual variables during sub-maximal and maximal running. Fifteen well-trained endurance athletes (mean+/-s: age 27.1+/-4.8 years, VO(2max) 63.7+/-4.9 ml x min(-1) x kg(-1)) performed four sub-maximal (approximately 70% VO(2max)) and maximal tests with and without different compression stockings, tights, and whole-body compression suits. Arterial lactate concentration, oxygen saturation and partial pressure, pH, oxygen uptake, and ratings of muscle soreness were recorded before, during, and after all tests. In addition, we assessed time to exhaustion. Sub-maximal (P=0.22) and maximal oxygen uptake (P=0.26), arterial lactate concentration (P=0.16; 0.20), pH (P=0.23; 0.46), oxygen saturation (P=0.13; 0.26), and oxygen partial pressure (P=0.09; 0.20) did not differ between the types of clothing (effect sizes=0.00-0.45). Ratings of perceived exertion (P=0.10; 0.15), muscle soreness (P=0.09; 0.10) and time to exhaustion (P=0.16) were also unaffected by the different clothing (effect sizes=0.28-0.85). This was the first study to evaluate the effect on endurance performance of different types of compression clothing with increasing amounts of compressive surface. Overall, there were no performance benefits when using the compression garments.

  3. Comparing the Effects of Rest and Massage on Return to Homeostasis Following Submaximal Aerobic Exercise: a Case Study.

    Science.gov (United States)

    Resnick, Portia B

    2016-03-01

    Postexercise massage can be used to help promote recovery from exercise on the cellular level, as well as systemically by increasing parasympathetic activity. No studies to date have been done to assess the effects of massage on postexercise metabolic changes, including excess postexercise oxygen consumption (EPOC). The purpose of this study was to compare the effects of massage recovery and resting recovery on a subject's heart rate variability and selected metabolic effects following a submaximal treadmill exercise session. One healthy 24-year-old female subject performed 30 minutes of submaximal treadmill exercise prior to resting or massage recovery sessions. Metabolic data were collected throughout the exercise sessions and at three 10 minute intervals postexercise. Heart rate variability was evaluated for 10 minutes after each of two 30-minute recovery sessions, either resting or massage. Heart rate returned to below resting levels (73 bpm) with 30 and 60 minutes of massage recovery (72 bpm and 63 bpm, respectively) compared to 30 and 60 minutes of resting recovery (77 bpm and 74 bpm, respectively). Heart rate variability data showed a more immediate shift to the parasympathetic state following 30 minutes of massage (1.152 LF/HF ratio) versus the 30-minute resting recovery (6.91 LF/HF ratio). It took 60 minutes of resting recovery to reach similar heart rate variability levels (1.216 LF/HF) found after 30 minutes of massage. Ventilations after 30 minutes of massage recovery averaged 7.1 bpm compared to 17.9 bpm after 30 minutes of resting recovery. No differences in EPOC were observed through either the resting or massage recovery based on the metabolic data collected. Massage was used to help the subject shift into parasympathetic activity more quickly than rest alone following a submaximal exercise session.

  4. Comparing the Effects of Rest and Massage on Return to Homeostasis Following Submaximal Aerobic Exercise: a Case Study

    Science.gov (United States)

    Resnick, Portia B.

    2016-01-01

    Introduction Postexercise massage can be used to help promote recovery from exercise on the cellular level, as well as systemically by increasing parasympathetic activity. No studies to date have been done to assess the effects of massage on postexercise metabolic changes, including excess postexercise oxygen consumption (EPOC). The purpose of this study was to compare the effects of massage recovery and resting recovery on a subject’s heart rate variability and selected metabolic effects following a submaximal treadmill exercise session. Methods One healthy 24-year-old female subject performed 30 minutes of submaximal treadmill exercise prior to resting or massage recovery sessions. Metabolic data were collected throughout the exercise sessions and at three 10 minute intervals postexercise. Heart rate variability was evaluated for 10 minutes after each of two 30-minute recovery sessions, either resting or massage. Results Heart rate returned to below resting levels (73 bpm) with 30 and 60 minutes of massage recovery (72 bpm and 63 bpm, respectively) compared to 30 and 60 minutes of resting recovery (77 bpm and 74 bpm, respectively). Heart rate variability data showed a more immediate shift to the parasympathetic state following 30 minutes of massage (1.152 LF/HF ratio) versus the 30-minute resting recovery (6.91 LF/HF ratio). It took 60 minutes of resting recovery to reach similar heart rate variability levels (1.216 LF/HF) found after 30 minutes of massage. Ventilations after 30 minutes of massage recovery averaged 7.1 bpm compared to 17.9 bpm after 30 minutes of resting recovery. Conclusions No differences in EPOC were observed through either the resting or massage recovery based on the metabolic data collected. Massage was used to help the subject shift into parasympathetic activity more quickly than rest alone following a submaximal exercise session. PMID:26977215

  5. Muscular and non-muscular contributions to maximum power cycling in children and adults: implications for developmental motor control

    OpenAIRE

    Korff, T.; Hunter, EL; Martin, JC

    2009-01-01

    This article is available open access through the publisher’s website at the link below. During submaximal cycling, children demonstrate a different distribution between muscular and non-muscular (gravitational and motion-dependent) forces when compared with adults. This is partly due to anthropometric differences. In this study, we tested the hypothesis that during maximum power cycling, children would construct the task (in terms of the distribution between muscular and non-muscular peda...

  6. Evaluation of the American College of Sports Medicine submaximal treadmill running test for predicting VO2max.

    Science.gov (United States)

    Marsh, Clare E

    2012-02-01

    The purpose of this study was to assess the validity of the American College of Sports Medicine's (ACSM's) submaximal treadmill running test in predicting VO2max. Twenty-one moderately well-trained men aged 18-34 years performed 1 maximal treadmill test to determine maximal oxygen uptake (M VO2max) and 2 submaximal treadmill tests using 4 stages of continuous submaximal exercise. Estimated VO2max was predicted by extrapolation to age-predicted maximal heart rate (HRmax) and calculated in 2 ways: using data from all submaximal stages between 110 b·min(-1) and 85% HRmax (P VO2max-All), and using data from the last 2 stages only (P VO2max-2). The measured VO2max was overestimated by 3% on average for the group but was not significantly different to predicted VO2max (1-way analysis of variance [ANOVA] p = 0.695; M VO2max = 53.01 ± 5.38; P VO2max-All = 54.27 ± 7.16; P VO2max-2 = 54.99 ± 7.69 ml·kg(-1)·min(-1)), although M VO2max was not overestimated in all the participants--it was underestimated in 30% of observations. Pearson's correlation, standard error of estimate (SEE), and total error (E) between measured and predicted VO2max were r = 0.646, 4.35, 4.08 ml·kg(-1)·min(-1) (P VO2max-All) and r = 0.642, 4.21, 3.98 ml·kg(-1)·min(-1) (P VO2max-2) indicating that the accuracy in prediction (error) was very similar whether using P VO2max-All or P VO2max-2, with up to 70% of the participants predicted scores within 1 SEE (∼4 ml·kg(-1)·min(-1)) of M VO2max. In conclusion, the ACSM equation provides a reasonably good estimation of VO2max with no difference in predictive accuracy between P VO2max-2 and P VO2max-All, and hence, either approach may be equally useful in tracking an individual's aerobic fitness over time. However, if a precise knowledge of VO2max is required, then it is recommended that this be measured directly.

  7. Cold exposure enhances fat utilization but not non-esterified fatty acids, glycerol or catecholamines availability during submaximal walking and running.

    Science.gov (United States)

    Gagnon, Dominique D; Rintamäki, Hannu; Gagnon, Sheila S; Cheung, Stephen S; Herzig, Karl-Heinz; Porvari, Katja; Kyröläinen, Heikki

    2013-01-01

    Cold exposure modulates the use of carbohydrates (CHOs) and fat during exercise. This phenomenon has mostly been observed in controlled cycling studies, but not during walking and running when core temperature and oxygen consumption are controlled, as both may alter energy metabolism. This study aimed at examining energy substrate availability and utilization during walking and running in the cold when core temperature and oxygen consumption are maintained. Ten lightly clothed male subjects walked or ran for 60-min, at 50% and 70% of maximal oxygen consumption, respectively, in a climatic chamber set at 0°C or 22°C. Thermal, cardiovascular, and oxidative responses were measured every 15-min during exercise. Blood samples for serum non-esterified fatty acids (NEFAs), glycerol, glucose, beta-hydroxybutyrate (BHB), plasma catecholamines, and serum lipids were collected immediately prior, and at 30- and 60-min of exercise. Skin temperature strongly decreased while core temperature did not change during cold trials. Heart rate (HR) was also lower in cold trials. A rise in fat utilization in the cold was seen through lower respiratory quotient (RQ) (-0.03 ± 0.02), greater fat oxidation (+0.14 ± 0.13 g · min(-1)) and contribution of fat to total energy expenditure (+1.62 ± 1.99 kcal · min(-1)). No differences from cold exposure were observed in blood parameters. During submaximal walking and running, a greater reliance on derived fat sources occurs in the cold, despite the absence of concurrent alterations in NEFAs, glycerol, or catecholamine concentrations. This disparity may suggest a greater reliance on intra-muscular energy sources such as triglycerides during both walking and running.

  8. Cold exposure enhances fat utilization but not non-esterified fatty acids, glycerol or catecholamines availability during submaximal walking and running

    Directory of Open Access Journals (Sweden)

    Dominique Daniel Gagnon

    2013-05-01

    Full Text Available Cold exposure modulates the use of carbohydrates and fat during exercise. This phenomenon has mostly been observed in controlled cycling studies, but not during walking and running when core temperature and oxygen consumption are controlled, as both may alter energy metabolism. This study aimed at examining energy substrate availability and utilization during walking and running in the cold when core temperature and oxygen consumption are maintained. Ten lightly clothed male subjects walked or ran for 60-min, at 50% and 70% of maximal oxygen consumption, respectively, in a climatic chamber set at 0°C or 22°C. Thermal, cardiovascular, and oxidative responses were measured every 15-min during exercise. Blood samples for serum non-esterified fatty acids, glycerol, glucose, beta-hydroxybutyrate, plasma catecholamines, and serum lipids were collected immediately prior, and at 30- and 60-min of exercise. Skin temperature strongly decreased while core temperature did not change during cold trials. Heart rate was also lower in cold trials. A rise in fat utilization in the cold was seen through lower respiratory quotient (-0.03 ± 0.02, greater fat oxidation (+0.14 ± 0.13 g•min-1 and contribution of fat to total energy expenditure (+1.62 ± 1.99 kcal•min-1. No differences from cold exposure were observed in blood parameters. During submaximal walking and running, a greater reliance on derived fat sources occurs in the cold, despite the absence of concurrent alterations in non-esterified fatty acids, glycerol, or catecholamine concentrations. This disparity may suggest a greater reliance on intra-muscular energy sources such as triglycerides during both walking and running.

  9. The effect of differing intensities of acute cycling on preadolescent academic achievement.

    Science.gov (United States)

    Duncan, Michael; Johnson, Andrew

    2014-01-01

    The present study examined the effects of differing intensity levels of acute exercise on preadolescent academic ability. In a repeated measures design, 18 preadolescent participants (mean age±S.D.= 9.8±1.4 years: 9 male and 9 female) completed the Wide Range Achievement Test (WRAT 4) following 20 minutes of rest, 20-minutes on a cycling ergometer at 50% maximal heart rate reserve (HRR), and 20-minutes on a cycling ergometer at 75% HRR on separate days. Exercise was found to improve spelling irrespective of intensity level. Moderate levels of exercise improved reading although the effect of high levels of intensity is less clear. Both intensity levels impaired arithmetic, whilst sentence comprehension was unaffected. These findings further support the past research that indicates acute bouts of exercise can selectively improve cognition in preadolescent children. However, the present study finds no support for the notion that increasing the intensity of exercise accentuates benefits.

  10. Test retest reliability and minimal detectable change of a novel submaximal graded exercise test in the measurement of graded exercise test duration.

    Science.gov (United States)

    Taylor, James D; Bandy, William D; Whittemore, Joe D

    2011-05-01

    Measurement of graded exercise test duration is clinically important and can be assessed by maximal graded exercise testing. Yet, limitations of maximal graded exercise testing exist. An alternative to maximal graded exercise testing is submaximal graded exercise testing. However, no studies have investigated the reliability of a submaximal graded exercise test in the measurement of graded exercise test duration. The purpose of this study was to determine the test-retest reliability and minimal detectable change (MDC) of a novel submaximal graded exercise test in the measurement of graded exercise test duration. Fifteen people (4 men, 11 women) with a mean age of 26.20 years (SD = 9.04) participated in this study. A novel submaximal graded exercise test was used to measure graded exercise test duration for each participant. Endpoints of the test were either 85% of age-predicted maximum heart rate or voluntarily stopping the test, whichever endpoint occurred first. Heart rate and graded exercise test duration were constantly measured throughout the test. Graded exercise test duration was defined as the total duration (minutes) of the test. For all participants, the submaximal graded exercise test was conducted at baseline and 48-72 hours thereafter. The intraclass correlation coefficient for the test-retest reliability of the test in determining graded exercise test duration was 0.94 (95% CI = 0.83-0.98). The MDC of the test in the measurement of graded exercise test duration was 0.86 minutes. The results suggest that clinicians can use this novel submaximal graded exercise test to reliably measure graded exercise test duration with a measurement error, as expressed by the MDC, of 0.86 minutes.

  11. Isokinetic performance capacity of trunk muscles. Part II: Coefficient of variation in isokinetic measurement in maximal effort and in submaximal effort.

    Science.gov (United States)

    Luoto, S; Hupli, M; Alaranta, H; Hurri, H

    1996-12-01

    It has been claimed that with the aid of isokinetic trunk strength measuring devices it is possible to distinguish true muscular weakness from submaximal effort in the test. This proposition is based on the presumption that in the isokinetic trunk strength test identical performances can only be reproduced by maximal effort. The purpose of this study was to investigate whether it is possible to distinguish maximal effort from submaximal with the aid of the coefficient of variation (CV) in an isokinetic trunk muscle strength test. The study group included 35 (21 male and 14 female) subjects of whom 12 were healthy, 10 had a mild low-back pain and 13 had a more severe chronic low-back pain. The subjects performed five consecutive bendings both with maximal (100%) and submaximal (50%) efforts at a speed of 90 degrees/second. In maximal effort only healthy subjects reached an average level of CV close to 10% both in extension and in flexion. In the chronic low-back pain group the average CV was close to 20%. The difference in CV was statistically significant (p < 0.05-0.02) between the healthy and the chronic low-back pain subjects. In the submaximal effort all health groups had a CV of approximately 20% or more and no significant differences were found. The group of slightly variable measurements (CV = 11-20%) was remarkably large in both the maximal and submaximal effort. The results suggest that an effort with a CV of 11-20% cannot be classified as definitely submaximal or maximal. When the CV is less than 10% the effort can be fairly certainly classified as maximal.

  12. Oxygen uptake efficiency slope, a new submaximal parameter in evaluating exercise capacity in chronic heart failure patients.

    Science.gov (United States)

    Van Laethem, Christophe; Bartunek, Jozef; Goethals, Marc; Nellens, Paul; Andries, Erik; Vanderheyden, Marc

    2005-01-01

    The oxygen uptake efficiency slope (OUES) is a new submaximal parameter which objectively predicts the maximal exercise capacity in children and healthy subjects. However, the usefulness of OUES in adult patients with and without advanced heart failure remains undetermined. The present study investigates the stability and the usefulness of OUES in adult cardiac patients with and without heart failure. Forty-five patients with advanced heart failure (group A) and 35 patients with ischemic heart disease but normal left ventricular ejection fraction (group B) performed a maximal exercise test. PeakVO2 and percentage of predicted peakVO2 were markers of maximal exercise capacity, whereas OUES, ventilatory anaerobic threshold (VAT), and slope VE/VCO2 were calculated as parameters of submaximal exercise. Group A patients had lower peakVO2 (P slope VE/VCO2 (P slope VE/VCO2, and OUES (all P slope VE/VCO2 (r = -.492, P failure patients unable to perform a maximal exercise test. Further studies are needed to confirm our hypothesis.

  13. Comparing VO2max determined by using the relation between heart rate and accelerometry with submaximal estimated VO2max.

    Science.gov (United States)

    Tönis, T M; Gorter, K; Vollenbroek-Hutten, M M R; Hermens, H

    2012-08-01

    An exploratory study to identify parameters that can be used for estimating a subject's cardio-respiratory physical fitness level, expressed as VO2max, from a combination of heart rate and 3D accelerometer data. Data were gathered from 41 healthy subjects (23 male, 18 female) aged between 20 and 29 years. The measurement protocol consisted of a sub-maximal single stage treadmill walking test for VO2max estimation followed by a walking test at two different speeds (4 and 5.5 kmh-1) for parameter determination. The relation between measured heart rate and accelerometer output at different walking speeds was used to get an indication of exercise intensity and the corresponding heart rate at that intensity. Regression analysis was performed using general subject measures (age, gender, weight, length, BMI) and intercept and slope of the relation between heart rate and accelerometer output during walking as independent variables to estimate the VO2max. A linear regression model using a combination of the slope and intercept parameters, together with gender revealed the highest percentage of explained variance (R2 = 0.90) and had a standard error of the estimate (SEE) of 2.052 mL O2kg-1min-1 with VO2max. Results are comparable with current commonly used sub-maximal laboratory tests to estimate VO2max. The combination of heart rate and accelerometer data seems promising for ambulant estimation of VO2max-.

  14. Regadenoson in Europe: first-year experience of regadenoson stress combined with submaximal exercise in patients undergoing myocardial perfusion scintigraphy.

    Science.gov (United States)

    Brinkert, M; Reyes, E; Walker, S; Latus, K; Maenhout, A; Mizumoto, R; Nkomo, C; Standbridge, K; Wechalekar, K; Underwood, S R

    2014-03-01

    Regadenoson was approved for clinical use in Europe in 2011. Since then, it has become the default form of stress at our institution. We have assessed the side-effect profile and tolerability of regadenoson in patients undergoing clinically indicated myocardial perfusion scintigraphy between July 2011 and July 2012. Clinical, stress and imaging data were recorded prospectively. Symptoms during stress were recorded and defined as mild, moderate or severe. An adverse event was defined as any symptom that persisted for more than 30 min or that required investigation or treatment. Of 1,764 consecutive patients, 1,581 (90%) received regadenoson combined with submaximal exercise unless contraindicated. Symptoms were common (63%) but transient and well-tolerated. The severity of symptoms was recorded in most patients as mild (84%). Dyspnoea (36%) and chest discomfort (12%) were the commonest side effects. Adverse events were reported in eight patients (0.5%), thought to be vasovagal in seven of these. All patients recovered fully without sequelae. There were no deaths, myocardial infarction or hospital admissions. Regadenoson stress was performed in 206 patients (12%) with asthma or chronic obstructive pulmonary disease (COPD) without bronchospasm or any other major side effect. We studied the symptom profile of regadenoson in the largest European cohort to date. Regadenoson combined with submaximal exercise was well tolerated, notably also in patients with asthma or COPD. The majority of regadenoson-related adverse events were vasovagal episodes without sequelae.

  15. Comparing para-rowing set-ups on an ergometer using kinematic movement patterns of able-bodied rowers.

    Science.gov (United States)

    Cutler, B; Eger, T; Merritt, T; Godwin, A

    2017-04-01

    While numerous studies have investigated the biomechanics of able-bodied rowing, few studies have been completed with para-rowing set-ups. The purpose of this research was to provide benchmark data for handle kinetics and joint kinematics for able-bodied athletes rowing in para- rowing set-ups on an indoor ergometer. Able-bodied varsity rowers performed maximal trials in three para-rowing set-ups; Legs, Trunk and Arms (LTA), Trunk and Arms (TA) and Arms and Shoulders (AS) rowing. The handle force kinetics of the LTA stroke were comparable to the values for able-bodied literature. Lumbar flexion at the catch, extension at the finish and total range of motion were, however, greater than values in the literature for able-bodied athletes in the LTA set-up. Additionally, rowers in TA and AS set-ups utilised more extreme ranges of motion for lumbar flexion, elbow flexion and shoulder abduction than the LTA set-up. This study provides the first biomechanical values of the para-rowing strokes for researchers, coaches and athletes to use while promoting the safest training programmes possible for para-rowing.

  16. Monitoring Training Progress During Exercise Training in Cancer Survivors : A Submaximal Exercise Test as an Alternative for a Maximal Exercise Test?

    NARCIS (Netherlands)

    May, Anne M.; van Weert, Ellen; Korstjens, Irene; Hoekstra-Weebers, Josette E.; van der Schans, Cees P.; Zonderland, Maria L.; Mesters, Ilse; van den Borne, Bart; Ros, Wynand J.

    May AM, van Weert E, Korstjens 1, Hoekstra-Weebers JE, van der Schans CP, Zonderland ML, Mesters 1, van den Borne B, Ros WJ. Monitoring training progress during exercise training in cancer survivors: a submaximal exercise test as an alternative for a maximal exercise test? Arch Phys Med Rehabil

  17. Assessment of muscle endurance of the knee extensor muscles in adolescents with spastic cerebral palsy using a submaximal repetitions-to-fatigue protocol.

    Science.gov (United States)

    Eken, Maaike M; Dallmeijer, Annet J; Doorenbosch, Caroline A; Dekkers, Hurnet; Becher, Jules G; Houdijk, Han

    2014-10-01

    To compare muscle endurance in adolescents with spastic cerebral palsy (CP) with typically developing (TD) peers using a submaximal repetitions-to-fatigue (RTF) protocol. Cross sectional. Human motion laboratory. Adolescents with spastic CP (n=16; Gross Motor Function Classification System levels I or II) and TD adolescents (n=18) within the age range of 12 to 19 years old. Not applicable. Each participant performed 3 RTF tests at different submaximal loads, ranging from 50% to 90% of their maximal voluntary knee extension torque. The relation between the number of repetitions (repetition maximum [RM]) and imposed submaximal relative (percent of maximal voluntary torque [%MVT]) and absolute (Nm/kg) torque was quantified. To compare adolescents with CP with TD adolescents, a mixed linear model was used to construct load endurance curves. Surface electromyography of quadriceps muscles was measured to assess changes in normalized amplitude and median frequency (MF) as physiological indicators of muscle fatigue. Adolescents with CP showed a larger decrease in %MVT per RM than TD adolescents (Pmuscles in all tests for both groups. Electromyographic MF decreased significantly (Pmuscle fatigue were reached. Adolescents with CP show slightly lower muscle endurance compared with TD adolescents on a submaximal RTF protocol, which is in contrast with earlier findings in a maximal voluntary fatigue protocol. Accordingly, adolescents with CP have a reduced capacity to endure activities at similar relative loads compared with TD adolescents. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  18. Dichloroacetate therapy attenuates the blood lactate response to submaximal exercise in patients with defects in mitochondrial energy metabolism.

    Science.gov (United States)

    Duncan, G E; Perkins, L A; Theriaque, D W; Neiberger, R E; Stacpoole, P W

    2004-04-01

    We determined acute and chronic effects of dichloroacetate (DCA) on maximal (MAX) and submaximal (SUB) exercise responses in patients with abnormal mitochondrial energetics. Subjects (n = 9) completed a MAX treadmill bout 1 h after ingesting 25 mg/kg DCA or placebo (PL). A 15-min SUB bout was completed the next day while receiving the same treatment. After a 1-d washout, MAX and SUB were repeated while receiving the alternate treatment (acute). Gas exchange and heart rate were measured throughout all tests. Blood lactate (Bla) was measured 0, 3, and 10 min after MAX, and 5, 10, and 15 min during SUB. MAX and SUB were repeated after 3 months of daily DCA or PL. After a 2-wk washout, a final MAX and SUB were completed after 3 months of alternate treatment (chronic). Average Bla during SUB was lower (P abnormal mitochondrial energetics.

  19. Torque decrease during submaximal evoked contractions of the quadriceps muscle is linked not only to muscle fatigue.

    Science.gov (United States)

    Matkowski, Boris; Lepers, Romuald; Martin, Alain

    2015-05-01

    The aim of this study was to analyze the neuromuscular mechanisms involved in the torque decrease induced by submaximal electromyostimulation (EMS) of the quadriceps muscle. It was hypothesized that torque decrease after EMS would reflect the fatigability of the activated motor units (MUs), but also a reduction in the number of MUs recruited as a result of changes in axonal excitability threshold. Two experiments were performed on 20 men to analyze 1) the supramaximal twitch superimposed and evoked at rest during EMS (Experiment 1, n = 9) and 2) the twitch response and torque-frequency relation of the MUs activated by EMS (Experiment 2, n = 11). Torque loss was assessed by 15 EMS-evoked contractions (50 Hz; 6 s on/6 s off), elicited at a constant intensity that evoked 20% of the maximal voluntary contraction (MVC) torque. The same stimulation intensity delivered over the muscles was used to induce the torque-frequency relation and the single electrical pulse evoked after each EMS contraction (Experiment 2). In Experiment 1, supramaximal twitch was induced by femoral nerve stimulation. Torque decreased by ~60% during EMS-evoked contractions and by only ~18% during MVCs. This was accompanied by a rightward shift of the torque-frequency relation of MUs activated and an increase of the ratio between the superimposed and posttetanic maximal twitch evoked during EMS contraction. These findings suggest that the torque decrease observed during submaximal EMS-evoked contractions involved muscular mechanisms but also a reduction in the number of MUs recruited due to changes in axonal excitability. Copyright © 2015 the American Physiological Society.

  20. Core Temperature Measurement During Submaximal Exercise: Esophageal, Rectal, and Intestinal Temperatures

    Science.gov (United States)

    Lee, Stuart M. C.; Williams, W. Jon; Schneider, Suzanne M.

    2000-01-01

    The purpose of this study was to determine if intestinal temperature (Tin) might be in acceptable alternative to esophageal (Tes) and rectal temperature (Trec) to assess thermoregulation during supine exercise. We hypothesized that Tin would have values similar to Tes and a response time similar to Trec, but the rate of temperature change across time would not be different between measurement sites. Seven subjects completed a continuous supine protocol of 20 min of rest, 20 min of cycle exercise at 40% peak oxygen consumption (VO2pk), 20 min of cycle exercise at 65% V02pk, and 20 min of recovery. Tes, Trec, and Tin were recorded each min throughout the test. Temperatures were not different after 20 min of rest, but Trec was less than the Tes and Tin at the end of the 40% and 65% VO2pk stages. After 20 min of recovery, Tes was less than either Trec or Tin, which were not different from each other. Time to threshold for increased temperature from rest was greater for Trec than Tes but not different from Tin. Time to reach peak temperature was greater for Tin and Trec than Tes. Similarly, time to a decrease in temperature after exercise was greater for Trec than Tes, but not different from Tin. The rate of temperature change from threshold to the end of the 40% VO2pk stage was not different between measurement sites. However, the rate of change during recovery was more negative for Tes than Tin and Trec, which were different from each other. Measurement of Tin may he an acceptable alternative to Tes and Trec with an understanding of its limitations.

  1. Developing new VO2max prediction models from maximal, submaximal and questionnaire variables using support vector machines combined with feature selection.

    Science.gov (United States)

    Abut, Fatih; Akay, Mehmet Fatih; George, James

    2016-12-01

    Maximal oxygen uptake (VO2max) is an essential part of health and physical fitness, and refers to the highest rate of oxygen consumption an individual can attain during exhaustive exercise. In this study, for the first time in the literature, we combine the triple of maximal, submaximal and questionnaire variables to propose new VO2max prediction models using Support Vector Machines (SVM's) combined with the Relief-F feature selector to predict and reveal the distinct predictors of VO2max. For comparison purposes, hybrid models based on double combinations of maximal, submaximal and questionnaire variables have also been developed. By utilizing 10-fold cross-validation, the performance of the models has been calculated using multiple correlation coefficient (R) and root mean square error (RMSE). The results show that the best values of R and RMSE, with 0.94 and 2.92mLkg-1min-1 respectively, have been obtained by combining the triple of relevantly identified maximal, submaximal and questionnaire variables. Compared with the results of the rest of hybrid models in this study and the other prediction models in literature, the reported values of R and RMSE have been found to be considerably more accurate. The predictor variables gender, age, maximal heart rate (MX-HR), submaximal ending speed (SM-ES) of the treadmill and Perceived Functional Ability (Q-PFA) questionnaire have been found to be the most relevant variables in predicting VO2max. The results have also been compared with that of Multilayer Perceptron (MLP) and Tree Boost (TB), and it is seen that SVM significantly outperforms other regression methods for prediction of VO2max. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Evaluation of Maximal Oxygen Uptake and Submaximal Estimates of VO2max Before, During, and After Long Duration International Space Station Missions

    Science.gov (United States)

    2008-01-01

    Evaluation of Maximal Oxygen Uptake and Submaximal Estimates of VO2max Before, During, and After Long Duration International Space Station Missions (VO2max) will document changes in maximum oxygen uptake for crewmembers onboard the International Space Station (ISS) on long-duration missions, greater than 90 days. This investigation will establish the characteristics of VO2max during flight and assess the validity of the current methods of tracking aerobic capacity change during and following the ISS missions.

  3. Effects of Submaximal Aerobic Exercise on Regulatory T Cell Markers of Male Patients Suffering from Ischemic Heart Disease.

    Science.gov (United States)

    Raygan, Fariba; Sayyah, Mansour; Janesar Qamsari, Seyed Mohammad Reza; Nikoueinejad, Hassan; Sehat, Mojtaba

    2017-02-01

    There are confirmed beneficiary effects of exercise on atherosclerotic inflammation of ischemia-associated heart diseases. The purpose of this study was to evaluate the effect of aerobic exercise on T-regulatory cell markers of IL-35 as well as FoxP3 and T-helper2 marker of IL-33 in patients with ischemic heart disease (IHD). This research was performed on 44 asymptomatic male patients with ischemic heart disease. The participants were randomly assigned into two groups of submaximal aerobic exercise and control group. Blood samples were collected before and after the termination of the exercise protocol. Serum levels of IL-35 and IL-33 as well as the amount of FoxP3 gene expression in peripheral blood mononuclear cells were measured by Elisa and Real time PCR, respectively. Serum levels of IL-35 (p=0.001) as well as the amount of FoxP3 gene expression increased significantly (p=0.012)  in exercise group even after controlling the likely confounding effects of age, length of ischemia, duration of the disease, and the amount of such factors before exercise (p≤0.042). It seems that exercise may yield a better control of atherosclerotic inflammation in patients with ischemic heart disease through the induction of regulatory T cells.

  4. Identification of patients at low risk of dying after acute myocardial infarction, by simple clinical and submaximal exercise test criteria.

    Science.gov (United States)

    Campbell, S; A'Hern, R; Quigley, P; Vincent, R; Jewitt, D; Chamberlain, D

    1988-09-01

    A consecutive series of 559 hospital survivors of acute myocardial infarction aged less than 66 years were studied; 93 were designated prospectively as low-risk because they were suitable for early submaximal exercise testing and had none of the following clinical or exercise test 'risk factors': (1) angina for at least one month prior to infarction; (2) symptomatic ventricular arrhythmias, or (3) recurrent ischaemic pain, both after the first 24 h of infarction; (4) cardiac failure; (5) cardiomegaly; and (6) an abnormal exercise test (angina, ST-depression or poor blood pressure response). Altogether 301 patients were exercised; their mortality over a median follow-up of 2.4 years was 10.2%, versus 24.6% in the 258 patients not exercised (P = 0.0005). Absence of clinical 'risk factors' alone, in the exercised patients, identified 156 with a mortality of 5.4% versus 15.6% in the 145 with at least one clinical 'risk factor' (P = 0.004). The fully defined low-risk group comprised 93 of the former patients who had neither clinical nor exercise test 'risk factors'. None of these patients died compared with 19 of those with at least one 'risk factor' (mortality = 14.7%; P = 0.002). Their respective rates of non-fatal reinfarction were similar and never exceeded 5% per annum. Therefore, simple clinical and exercise test criteria can positively identify low-risk patients after infarction in whom secondary prevention may be inappropriate.

  5. Interaction effects of time of day and sub-maximal treadmill exercise on the main determinants of blood fluidity.

    Science.gov (United States)

    Ahmadizad, Sajad; Bassami, Minoo

    2010-01-01

    The purpose of this study was to investigate the effects of time of day on responses of the main determinants of blood rheology to acute endurance exercise. Ten healthy male subjects (age, 26.9 +/- 5.5 yr) performed two bouts of running at 65% of VO2peak for 45 min on a motorised treadmill in the morning (08:00 h) and evening (20:00 h), which were followed by 30 min recovery. The two exercise trials were performed in two separate days with 7 days intervening. Haemorheological variables were measured before, immediately after exercise and after recovery. Haematocrit, haemoglobin and RBC count were increased significantly (p evening trials and normalised following recovery, irrespective of time of day. Plasma viscosity increased significantly (F2,18 = 12.4, p exercise in both trials and returned to pre-exercise level at the end of recovery. Baseline values (p exercise were significantly affected by time of day. Neither a significant main effect of exercise nor a significant (p > 0.05) time-of-day effect was found for plasma proteins. It was concluded that sub-maximal running at 08:00 or 20:00 h does not induce different responses in the main determinant of blood rheology.

  6. Endurance and fatigue characteristics in the neck muscles during sub-maximal isometric test in patients with cervical radiculopathy.

    Science.gov (United States)

    Halvorsen, Marie; Abbott, Allan; Peolsson, Anneli; Dedering, Åsa

    2014-03-01

    The aim of the study was to compare myoelectric manifestation in neck muscle endurance and fatigue characteristics during sub-maximal isometric endurance test in patients with cervical radiculopathy and asymptomatic subjects. An additional aim was to explore associations between primary neck muscle endurance, myoelectric fatigability, and self-rated levels of fatigue, pain and subjective health measurements in patients with cervical radiculopathy. Muscle fatigue in the ventral and dorsal neck muscles was assessed in patients with cervical radiculopathy and in an asymptomatic group during an isometric neck muscle endurance test in prone and supine. 46 patients and 34 asymptomatic subjects participated. Surface electromyography signals were recorded from the sternocleidomastoid, cervical paraspinal muscles and upper and middle trapezius bilaterally during the endurance test. Subjective health measurements were assessed with questionnaires. The results showed altered neck muscle endurance in several of the muscles investigated with greater negative median frequency slope, greater variability, side imbalance, lower endurance time and higher experience of fatigue among the cervical radiculopathy patients compared with healthy subjects. Endurance times were significantly lower in both prone and in supine positions between the patients compared to asymptomatic subjects. During the neck muscle endurance test, fatigues in the upper trapezius muscles during the prone test and in the sternocleidomastoid muscles during the supine test were of more importance than self-perceived pain, fatigue, disability and kinesiophobia in predicting neck muscle endurance (NME). NME testing in the primary neck muscles seems to be an important factor to take into consideration in rehabilitation.

  7. Biogeochemical Cycling

    Science.gov (United States)

    Bebout, Brad; Fonda, Mark (Technical Monitor)

    2002-01-01

    This lecture will introduce the concept of biogeochemical cycling. The roles of microbes in the cycling of nutrients, production and consumption of trace gases, and mineralization will be briefly introduced.

  8. Effects of the menstrual cycle on exercise performance.

    Science.gov (United States)

    Janse de Jonge, Xanne A K

    2003-01-01

    This article reviews the potential effects of the female steroid hormone fluctuations during the menstrual cycle on exercise performance. The measurement of estrogen and progesterone concentration to verify menstrual cycle phase is a major consideration in this review. However, even when hormone concentrations are measured, the combination of differences in timing of testing, the high inter- and intra-individual variability in estrogen and progesterone concentration, the pulsatile nature of their secretion and their interaction, may easily obscure possible effects of the menstrual cycle on exercise performance. When focusing on studies using hormone verification and electrical stimulation to ensure maximal neural activation, the current literature suggests that fluctuations in female reproductive hormones throughout the menstrual cycle do not affect muscle contractile characteristics. Most research also reports no changes over the menstrual cycle for the many determinants of maximal oxygen consumption (VO2max), such as lactate response to exercise, bodyweight, plasma volume, haemoglobin concentration, heart rate and ventilation. Therefore, it is not surprising that the current literature indicates that VO2max is not affected by the menstrual cycle. These findings suggest that regularly menstruating female athletes, competing in strength-specific sports and intense anaerobic/aerobic sports, do not need to adjust for menstrual cycle phase to maximise performance. For prolonged exercise performance, however, the menstrual cycle may have an effect. Even though most research suggests that oxygen consumption, heart rate and rating of perceived exertion responses to sub-maximal steady-state exercise are not affected by the menstrual cycle, several studies report a higher cardiovascular strain during moderate exercise in the mid-luteal phase. Nevertheless, time to exhaustion at sub-maximal exercise intensities shows no change over the menstrual cycle. The significance of

  9. Adapted low intensity ergometer aerobic training for early and severely impaired stroke survivors: a pilot randomized controlled trial to explore its feasibility and efficacy.

    Science.gov (United States)

    Wang, Zun; Wang, Lei; Fan, Hongjuan; Jiang, Wenjun; Wang, Sheng; Gu, Zhaohua; Wang, Tong

    2014-09-01

    [Purpose] To evaluate the feasibility and efficacy of adapted low intensity ergometer aerobic training for early and severely impaired stroke survivors. [Subjects] The subjects were forty-eight early stroke survivors. [Methods] Eligible subjects were recruited and randomly assigned to an experimental group and a control group. Both groups participated in comprehensive rehabilitation training. Low intensity aerobic training was only performed by the experimental group. Outcome measures were the Fugl-Meyer motor score, Barthel index, exercise test time, peak heart rate, plasma glucose level and serum lipid profiles. [Results] Patients in the experimental group finished 88.6% of the total aerobic training sessions prescribed. In compliant participants (adherence≥80%), aerobic training significantly improved the Barthel index (from 40.1±21.1 to 79.2±14.2), Fugl-Meyer motor score (from 26.4±19.4 to 45.4±12.7), exercise test time (from 12.2±3.62 min to 13.9±3.6 min), 2-hour glucose level (from 9.22±1.16 mmol/L to 7.21±1.36 mmol/L) and homeostasis model of assessment for insulin resistence index (from 1.72±1.01 to 1.28±0.88). [Conclusion] Preliminary findings suggest that early and severely impaired stroke patients may benefit from low intensity ergometer aerobic training.

  10. Pulmonary and leg VO2 during submaximal exercise: implications for muscular efficiency

    Science.gov (United States)

    Poole, D. C.; Gaesser, G. A.; Hogan, M. C.; Knight, D. R.; Wagner, P. D.

    1992-01-01

    Insights into muscle energetics during exercise (e.g., muscular efficiency) are often inferred from measurements of pulmonary gas exchange. This procedure presupposes that changes of pulmonary O2 (VO2) associated with increases of external work reflect accurately the increased muscle VO2. The present investigation addressed this issue directly by making simultaneous determinations of pulmonary and leg VO2 over a range of work rates calculated to elicit 20-90% of maximum VO2 on the basis of prior incremental (25 or 30 W/min) cycle ergometry. VO2 for both legs was calculated as the product of twice one-leg blood flow (constant-infusion thermodilution) and arteriovenous O2 content difference across the leg. Measurements were made 3-5 min after each work rate imposition to avoid incorporation of the VO2 slow component above the lactate threshold. For all 17 subjects, the slope of pulmonary VO2 (9.9 +/- 0.2 ml O2.W-1.min-1) was not different (P greater than 0.05) from that for leg VO2 (9.2 +/- 0.6 ml O2.W-1.min-1). Estimation of "delta" efficiency (i.e., delta work accomplished divided by delta energy expended, calculated from slope of VO2 vs. work rate and a caloric equivalent for O2 of 4.985 cal/ml) using pulmonary VO2 measurements (29.1 +/- 0.6%) was likewise not significantly different (P greater than 0.05) from that made using leg VO2 measurements (33.7 +/- 2.4%). These data suggest that the net VO2 cost of metabolic "support" processes outside the exercising legs changes little over a relatively broad range of exercise intensities. Thus, under the conditions of this investigation, changes of VO2 measured from expired gas reflected closely those occurring within the exercising legs.

  11. Exercise performance over the menstrual cycle in temperate and hot, humid conditions.

    Science.gov (United States)

    Janse DE Jonge, Xanne A K; Thompson, Martin W; Chuter, Vivienne H; Silk, Leslie N; Thom, Jeanette M

    2012-11-01

    This study investigated the effects of the menstrual cycle on prolonged exercise performance both in temperate (20°C, 45% relative humidity) and hot, humid (32°C, 60% relative humidity) conditions. For each environmental condition, 12 recreationally active females were tested during the early follicular (day 3-6) and midluteal (day 19-25) phases, verified by measurement of estradiol and progesterone. For all four tests, thermoregulatory, cardiorespiratory, and perceptual responses were measured during 60 min of exercise at 60% of maximal oxygen consumption followed by an incremental test to exhaustion. No differences in exercise performance between menstrual cycle phases were found during temperate conditions (n = 8) despite a higher resting and submaximal exercise core temperature (Tc) in the luteal phase. In hot, humid conditions (n = 8), however, prolonged exercise performance, as exercise time to fatigue, was significantly reduced during the luteal phase. This finding was not only accompanied by higher resting and submaximal exercise Tc but also a higher rate of increase in Tc during the luteal phase. Furthermore, submaximal exercise HR, minute ventilation, and RPE measures were higher during the luteal phase in hot, humid conditions. No significant differences were found over the menstrual cycle in heat loss responses (partitional calorimetry, sweat rate, upper arm sweat composition) and Tc at exhaustion. In temperate conditions, no changes in prolonged exercise performance were found over the menstrual cycle, whereas in hot, humid conditions, performance was decreased during the luteal phase. The combination of both exercise and heat stress with the elevated luteal phase Tc at the onset of exercise resulted in physiological and perceptual changes and a greater thermosensitivity, which may explain the decrease in performance.

  12. High-frequency submaximal stimulation over muscle evokes centrally generated forces in human upper limb skeletal muscles.

    Science.gov (United States)

    Blouin, Jean-Sébastien; Walsh, Lee D; Nickolls, Peter; Gandevia, Simon C

    2009-02-01

    Control of posture and movement requires control of the output from motoneurons. Motoneurons of human lower limb muscles exhibit sustained, submaximal activity to high-frequency electrical trains, which has been hypothesized to be partly triggered by monosynaptic Ia afferents. The possibility to trigger such behavior in upper limb motoneurons and the potential unique role of Ia afferents to trigger such behavior remain unclear. Subjects (n = 9) received high-frequency trains of electrical stimuli over biceps brachii and flexor pollicis longus (FPL). We chose to study the FPL muscle because it has weak monosynaptic Ia afferent connectivity and it is involved in fine motor control of the thumb. Two types of stimulus trains (100-Hz bursts and triangular ramps) were tested at five intensities below painful levels. All subjects exhibited enhanced torque in biceps and FPL muscles after both types of high-frequency train. Torques also persisted after stimulation, particularly for the highest stimulus intensity. To separate the evoked torques that resulted from a peripheral mechanism (e.g., muscle potentiation) and that which resulted from a central origin, we studied FPL responses to high-frequency trains after complete combined nerve blocks of the median and radial nerves (n = 2). During the blocks, high-frequency trains over the FPL did not yield torque enhancements or persisting torques. These results suggest that enhanced contractions of central origin can be elicited in motoneurons innervating the upper limb, despite weak monosynaptic Ia connections for FPL. Their presence in a recently evolved human muscle (FPL) indicates that these enhanced contractions may have a broad role in controlling tonic postural outputs of hand muscles and that they may be available even for fine motor activities involving the thumb.

  13. Comparison of the pedalling performance induced by magnetic and electrical stimulation cycle ergometry in able-bodied subjects.

    Science.gov (United States)

    Szecsi, J; Straube, A; Fornusek, C

    2014-04-01

    The purpose of the study was to compare the mechanical power and work generated by able-bodied subjects during functional magnetic stimulation (FMS) vs. functional electrical stimulation (FES) induced ergometer training conditions. Both stimulation methods were applied at a 30 Hz frequency to the quadriceps muscles of 22 healthy able-bodied subjects to induce cycling for 4× four minutes or until exhaustion. FMS was performed via large surface, cooled coils, while FES was applied with a typical stimulation setup used for cycling. Significantly more (pstimulation induced pain and fatigue mechanisms of the neuromuscular system. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  14. Influence of obstructive sleep apnea syndrome in the fluctuation of the submaximal isometric torque of knee extensors in patients with early-grade osteoarthritis

    Science.gov (United States)

    Silva, Andressa; Mello, Marco T.; Serrão, Paula R.; Luz, Roberta P.; Bittencourt, Lia R.; Mattiello, Stela M.

    2015-01-01

    OBJECTIVE: The aim of this study was to investigate whether obstructive sleep apnea (OSA) alters the fluctuation of submaximal isometric torque of the knee extensors in patients with early-grade osteoarthritis (OA). METHOD: The study included 60 male volunteers, aged 40 to 70 years, divided into four groups: Group 1 (G1) - Control (n=15): without OA and without OSA; Group 2 (G2) (n=15): with OA and without OSA; Group 3 (G3) (n=15): without OA and with OSA; and Group 4 (G4) (n=15) with OA and with OSA. Five patients underwent maximal isometric contractions of 10 seconds duration each, with the knee at 60° of flexion to determine peak torque at 60°. To evaluate the fluctuation of torque, 5 submaximal isometric contractions (50% of maximum peak torque) of 10 seconds each, which were calculated from the standard deviation of torque and coefficient of variation, were performed. RESULTS: Significant differences were observed between groups for maximum peak torque, while G4 showed a lower value compared with G1 (p=0.005). Additionally, for the average torque exerted, G4 showed a lower value compared to the G1 (p=0.036). However, no differences were found between the groups for the standard deviation (p=0.844) and the coefficient of variation (p=0.143). CONCLUSION: The authors concluded that OSA did not change the parameters of the fluctuation of isometric submaximal torque of knee extensors in patients with early-grade OA. PMID:26443974

  15. Human skeletal muscle type 1 fibre distribution and response of stress-sensing proteins along the titin molecule after submaximal exhaustive exercise.

    Science.gov (United States)

    Koskinen, Satu O A; Kyröläinen, Heikki; Flink, Riina; Selänne, Harri P; Gagnon, Sheila S; Ahtiainen, Juha P; Nindl, Bradley C; Lehti, Maarit

    2017-11-01

    Early responses of stress-sensing proteins, muscle LIM protein (MLP), ankyrin repeat proteins (Ankrd1/CARP and Ankrd2/Arpp) and muscle-specific RING finger proteins (MuRF1 and MuRF2), along the titin molecule were investigated in the present experiment after submaximal exhaustive exercise. Ten healthy men performed continuous drop jumping unilaterally on a sledge apparatus with a submaximal height until complete exhaustion. Five stress-sensing proteins were analysed by mRNA measurements from biopsies obtained immediately and 3 h after the exercise from exercised vastus lateralis muscle while control biopsies were obtained from non-exercised legs before the exercise. Decreased maximal jump height and increased serum creatine kinase activities as indirect markers for muscle damage and HSP27 immunostainings on muscle biopsies as a direct marker for muscle damage indicated that the current exercised protocol caused muscle damage. mRNA levels for four (MLP, Ankrd1/CARP, MuRF1 and MuRF2) out of the five studied stress sensors significantly (p exercise. The magnitude of MLP and Ankrd2 responses was related to the proportion of type 1 myofibres. Our data showed that the submaximal exhaustive exercise with subject's own physical fitness level activates titin-based stretch-sensing proteins. These results suggest that both degenerative and regenerative pathways are activated in very early phase after the exercise or probably already during the exercise. Activation of these proteins represents an initial step forward adaptive remodelling of the exercised muscle and may also be involved in the initiation of myofibre repair.

  16. [Paraplegic cycling using functional electrical stimulation. Experimental and model-based study of power output].

    Science.gov (United States)

    Szecsi, J; Krafczyk, S; Quintern, J; Fiegel, M; Straube, A; Brandt, T

    2004-12-01

    Cycling using functional electrical stimulation offers paraplegics the possibility of muscle and cardiovascular training as well as the chance for independent locomotion. To investigate whether this method might be suitable for a large group of paraplegics, the first German feasibility study of functional electrical stimulation (FES) cycling with seven paraplegic patients was started at the beginning of 2003. Even at the beginning of the study, and without training, these patients were able to drive distances of 0.5-1.6 km. To stimulate cardiovascular adaptation processes in the case of FES ergometer training or to cover useful distances in the case of FES cycling, a minimum amount of generated mechanical output power is required, which as a rule cannot be achieved yet. In this study, we point out two particular aspects of FES cycling, which impair power output: prolonged fatigue mode and viscous joint friction of the paraplegic FES cyclist. We discuss current possibilities for increasing output power and endurance.

  17. Effects of preferred and nonpreferred music on continuous cycling exercise performance.

    Science.gov (United States)

    Nakamura, Priscila M; Pereira, Gleber; Papini, Camila B; Nakamura, Fábio Y; Kokubun, Eduardo

    2010-02-01

    The aim of this study was to investigate the effects of preferred and nonpreferred music on exercise distance, Heart Rate (HR), and Rating of Perceived Exertion (RPE) during continuous cycling exercise performed at high intensity. Fifteen participants performed five test sessions. During two sessions, they cycled with fixed workload on ergometer to determine the Critical Power (CP) intensity. Then, they performed three more sessions cycling at CP intensity: listening to Preferred Music, listening to Nonpreferred Music, and No Music. The HR responses in the exercise sessions did not differ among all conditions. However, the RPE was higher for Nonpreferred Music than in the other conditions. The performance under Preferred Music (9.8 +/- 4.6 km) was greater than under Nonpreferred Music (7.1 +/- 3.5 km) conditions. Therefore, listening to Preferred Music during continuous cycling exercise at high intensity can increase the exercise distance, and individuals listening to Nonpreferred Music can perceive more discomfort caused by the exercise.

  18. Acute effects of kinesio taping on a 6 s maximal cycling sprint performance.

    Science.gov (United States)

    Trecroci, Athos; Formenti, Damiano; Rossi, Alessio; Esposito, Fabio; Alberti, Giampietro

    2017-01-01

    Based on the hypothesis that tactile stimulation affects muscle activation levels, we theorized that taping vastus medialis and vastus lateralis muscles would improve a 6 s sprint cycling performance. Thus, the aim of this study was to determine whether the use of kinesio taping (KT) was helpful in increasing maximal-intensity cycling exercise. Sixteen active healthy subjects were enrolled in a randomized placebo, repeated measures design. All subjects were tested on a cycle ergometer under three conditions: without taping, taping along anterior thigh muscles and sham taping across the same muscle groups. Results showed a significant increase in peak power output and total work after the application compared to the condition with no tape applied (p < 0.05). No significant difference was found between the two modes of application. Our findings indicated that the tactile stimulation of KT applied longitudinally provided positive effects during a sprint cycling performance in healthy and active subjects.

  19. High-resolution phase-contrast MRI of aortic and pulmonary blood flow during rest and physical exercise using a MRI compatible bicycle ergometer

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Tim Frederik, E-mail: tim.weber@med.uni-heidelberg.de [Department of Diagnostic and Interventional Radiology, University Medical Center Heidelberg, INF 110, 69120 Heidelberg (Germany); Department of Radiology, German Cancer Research Center, INF 280, 69120 Heidelberg (Germany); Tengg-Kobligk, Hendrik von, E-mail: hendrik.tengg-kobligk@med.uni-heidelberg.de [Department of Diagnostic and Interventional Radiology, University Medical Center Heidelberg, INF 110, 69120 Heidelberg (Germany); Department of Radiology, German Cancer Research Center, INF 280, 69120 Heidelberg (Germany); Kopp-Schneider, Annette, E-mail: kopp@dkfz-heidelberg.de [Department of Biostatistics, German Cancer Research Center, INF 280, 69120 Heidelberg (Germany); Ley-Zaporozhan, Julia, E-mail: julia.ley-zaporozhan@med.uni-heidelberg.de [Department of Pediatric Radiology, University Medical Center Heidelberg, INF 430, 69120 Heidelberg (Germany); Kauczor, Hans-Ulrich, E-mail: hans-ulrich.kauczor@med.uni-heidelberg.de [Department of Diagnostic and Interventional Radiology, University Medical Center Heidelberg, INF 110, 69120 Heidelberg (Germany); Ley, Sebastian, E-mail: sebastian.ley@med.uni.heidelberg.de [Department of Radiology, German Cancer Research Center, INF 280, 69120 Heidelberg (Germany); Department of Pediatric Radiology, University Medical Center Heidelberg, INF 430, 69120 Heidelberg (Germany)

    2011-10-15

    Purpose: To establish high-resolution phase-contrast magnetic resonance imaging (PC-MRI) using a MRI compatible bicycle ergometer to quantify aortic and pulmonary blood flow during resting conditions and exercise. Materials and methods: In 20 healthy volunteers (mean age, 26.8 {+-} 5.0 years) high-resolution PC-MRI (mean temporal resolution, 7.4 {+-} 3.2 ms) was performed in the ascending aorta (AA) and main pulmonary artery (PA) during physical rest and three exercise stages: stage 1, no-load operation; stage 2, heart rate increase 40% compared to rest; stage 3, heart rate increase 80% compared to rest. Flow quantification in AA and PA included flow volume (FV), average velocity (AV), peak velocity (PV) and time to PV (TP). Results: In stage 1 only TP demonstrated a significant change. With progression to stage 2, all parameters altered significantly. Flow measurements during stage 3 evidenced further alterations only of AV and TP regarding both AA and PA. The deviation of the heart rate from the desired target value was significantly higher for stage 3 compared to stage 2, and 15% of the subjects did not reach the desired target heart rate of stage 3 at all. Conclusion: Flow quantification by high-resolution PC-MRI during exercise using a MRI compatible bicycle ergometer is feasible. Medium exercise stages are necessary and sufficient to demonstrate flow alterations in healthy volunteers. PC-MRI ergometry may give insights into aberrant hemodynamic conditions in patients with cardiovascular and pulmonary disease.

  20. Understanding recumbent cycling: instrumentation design and biomechanical analysis.

    Science.gov (United States)

    Reiser, Raoul F; Peterson, M L; Broker, Jeffrey P

    2002-01-01

    The recumbent cycling position (RCP) is gaining popularity, with both recumbent ergometers and bicycles available as an alternative to the standard, upright cycling position (SCP). However, very little is known about the RCP, creating a situation where uniformed choices are being made. A system was developed for measuring and analyzing the forces placed on a bicycle pedal during operation of a stationary ergometer in either the RCP or SCP. Clipless pedals were modified so that forces normal and tangential to the surface of the pedal could be measured in the plane of the bicyclist. Additionally, the angle of the pedal was measured relative to the crank arm, as well as crank arm angle, so that pedal force orientations in a global reference were known. The pedals were modified in such a way that they were structurally and functionally similar to their original design. After obtaining university-approved informed consent, a single RCP with similar included angle between torso and lower extremities to the SCP was compared by having 19 recreational cyclists pedal in both positions (60 rpm, 250 W). Both pedal forces and lower-extremity kinematics were measured and an inverse-dynamics analysis was performed. The energy transferred from the upper body to the lower extremities was significantly reduced in the RCP. Additionally, the amount of work done by knee flexion was significantly increased in the RCP while total work at the knee was not different. Due to these differences, depending on the situation, it may be more advantageous to select one cycling position over the other.

  1. Psychophysiological effects of synchronous versus asynchronous music during cycling.

    Science.gov (United States)

    Lim, Harry B T; Karageorghis, Costas I; Romer, Lee M; Bishop, Daniel T

    2014-02-01

    Synchronizing movement to a musical beat may reduce the metabolic cost of exercise, but findings to date have been equivocal. Our aim was to examine the degree to which the synchronous application of music moderates the metabolic demands of a cycle ergometer task. Twenty-three recreationally active men made two laboratory visits. During the first visit, participants completed a maximal incremental ramp test on a cycle ergometer. At the second visit, they completed four randomized 6-min cycling bouts at 90% of ventilatory threshold (control, metronome, synchronous music, and asynchronous music). Main outcome variables were oxygen uptake, HR, ratings of dyspnea and limb discomfort, affective valence, and arousal. No significant differences were evident for oxygen uptake. HR was lower under the metronome condition (122 ± 15 bpm) compared to asynchronous music (124 ± 17 bpm) and control (125 ± 16 bpm). Limb discomfort was lower while listening to the metronome (2.5 ± 1.2) and synchronous music (2.3 ± 1.1) compared to control (3.0 ± 1.5). Both music conditions, synchronous (1.9 ± 1.2) and asynchronous (2.1 ± 1.3), elicited more positive affective valence compared to metronome (1.2 ± 1.4) and control (1.2 ± 1.2), while arousal was higher with synchronous music (3.4 ± 0.9) compared to metronome (2.8 ± 1.0) and control (2.8 ± 0.9). Synchronizing movement to a rhythmic stimulus does not reduce metabolic cost but may lower limb discomfort. Moreover, synchronous music has a stronger effect on limb discomfort and arousal when compared to asynchronous music.

  2. Description of a standardized rehabilitation program based on sub-maximal eccentric following a platelet-rich plasma infiltration for jumper’s knee

    Science.gov (United States)

    Kaux, Jean-François; Forthomme, Bénédicte; Namurois, Marie-Hélène; Bauvir, Philippe; Defawe, Nathalie; Delvaux, François; Lehance, Cédric; Crielaard, Jean-Michel; Croisier, Jean-Louis

    2014-01-01

    Summary Introduction. Different series emphasized the necessity of rehabilitation program after infiltration of platelet-rich plasma (PRP) in case of tendinopathy. However, most of them describe only briefly the reeducation protocol and these programs vary. Our aim was to extensively describe a specific standardized rehabilitation program. Methods. After a review of literature of post-PRP infiltration protocols, we had developed a standardized rehabilitation protocol. This protocol was evaluated by 30 subjects with chronic jumper’s knee who. A standardised progressive sub-maximal eccentric program supervised by a physical therapist for 6 weeks was started 1 week post-infiltration. The patient benefited also from electromyostimulation, isometric strengthening and stretching of the quadriceps, cycloergometer and cryotherapy. After the supervised program, the patient had to make an auto-reeducation added to the reathletisation protocol for 6 more weeks which was followed by maintenance exercises up to 1 year. The assessments were made using a VAS, IKDC and VISA-P scores. Results. The VAS, IKDC and VISA-P scores decreased very significantly with time. The compliance to auto-reeducation was good. Conclusions. We proposed a simple and efficient protocol based on sub-maximal eccentric reeducation to add to PRP infiltrations in case of patellar tendinopathy. PMID:24932453

  3. Differences between sprint tests under laboratory and actual cycling conditions.

    Science.gov (United States)

    Bertucci, W; Taiar, R; Grappe, F

    2005-09-01

    The aim of this study was to compare the maximal power output (POpeak) and force-velocity relationships in sprint cycling obtained from a laboratory protocol and from a field test during actual cycling locomotion. Seven male competitive cyclists performed 6 sprints (3 in the seated position and 3 in the standing position) on an ergo-trainer (Tacx, Netherlands) and 6 sprints during actual cycling locomotion in a gymnasium. The bicycle was equipped with the SRM Training System (Schoberer Rad Messtechnik, Germany) to measure (200 Hz) the power output (PO, W), the pedalling cadence (rpm), and the velocity (kmxh-1). From these measurements, the maximal force on the pedal (Fmax), the theoretical maximal force (Fo, N) and the theoretical maximal pedalling cadence (V0, rpm) were determined. During each sprint test the lateral bicycle oscillations were measured from a video analysis. During standing and seated sprints in the gymnasium, Fo and Fmax were significantly higher (pestimation of the maximal power output, it is necessary to perform sprint tests during actual cycling locomotion. Thus, in the laboratory, it is advisable to use a cycle ergometer that enables natural lateral oscillations.

  4. Glacial cycles

    DEFF Research Database (Denmark)

    Kaufmann, R. K.; Juselius, Katarina

    and compare the accuracy of their in-sample simulations. Results indicate that strong statistical associations between endogenous climate variables are not enough for statistical models to reproduce glacial cycles. Rather, changes in solar insolation associated with changes in Earth's orbit are needed......We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr-present). To do so, we estimate models of varying complexity...

  5. Physiological responses and perceived exertion during cycling with superimposed electromyostimulation.

    Science.gov (United States)

    Wahl, Patrick; Schaerk, Jonas; Achtzehn, Silvia; Kleinöder, Heinz; Bloch, Wilhelm; Mester, Joachim

    2012-09-01

    The goal of the study was to evaluate and to quantify the effects of local electromyostimulation (EMS) during cycling on the cardiorespiratory system, muscle metabolism, and perceived exertion compared with cycling with no EMS. Ten healthy men (age: 24.6 ± 3.2 years, V[Combining Dot Above]O2max: 54.1 ± 6.0 ml·min·kg) performed 3 incremental cycle ergometer step tests, 1 without and 2 with EMS (30 and 85 Hz) until volitional exhaustion. Lactate values and respiratory exchange ratio were significantly higher at intensities ≥75% peak power output (PPO) when EMS was applied. Bicarbonate concentration, base excess (BE), and Pco2 were significantly lower when EMS was applied compared with the control at intensities ≥75% PPO. Saliva cortisol levels increased because of the exercise but were unaffected by EMS. Furthermore, EMS showed greater effects on CK levels 24 hours postexercise than normal cycling did. Rating of perceived exertion was significantly higher at 100% PPO with EMS. No statistical differences were found for heart rate, pH, and Po2 between the tested cycling modes. The main findings of this study are greater metabolic changes (lactate, respiratory exchange ratio, BE, (Equation is included in full-text article.), Pco2) during cycling with EMS compared with normal cycling independent of frequency, mainly visible at higher work rates. Because metabolic alterations are important for the induction of cellular signaling cascades and adaptations, these results lead to the hypothesis that applied EMS stimulations during cycling exercise might be an enhancing stimulus for skeletal muscle metabolism and related adaptations. Thus, superimposed EMS application during cycling could be beneficial to aerobic performance enhancements in athletes and in patients who cannot perform high workloads. However, the higher demand on skeletal muscles involved must be considered.

  6. CYCLE CONTROL

    African Journals Online (AJOL)

    changed to gestodene. Although large- scale comparative trials are needed to confirm this finding, evidence suggests that cycle control with gestodene is better than for monophasic preparations containing desogestrel, norgestimate or levonorgestrel,10 as well as for levonorg- estrel-or norethisterone-containing triphasics.

  7. Menu Cycles.

    Science.gov (United States)

    Clayton, Alfred; Almony, John

    The curriculum guide for commercial foods instruction is designed to aid the teacher in communicating the importance of menu cycles in commercial food production. It also provides information about the necessary steps in getting food from the raw form to the finished product, and then to the consumer. In addition to providing information on how to…

  8. Simple cycles

    OpenAIRE

    Rivin, Igor

    1999-01-01

    We obtain sharp bounds for the number of n-cycles in a finite graph as a function of the number of edges, and prove that the complete graph is optimal in more ways than could be imagined. En route, we prove some sharp estimates on power sums.

  9. Happy Cycling

    DEFF Research Database (Denmark)

    Geert Jensen, Birgitte; Nielsen, Tom

    2013-01-01

    og Interaktions Design, Aarhus Universitet under opgave teamet: ”Happy Cycling City – Aarhus”. Udfordringen i studieopgaven var at vise nye attraktive løsningsmuligheder i forhold til cyklens og cyklismens integration i byrum samt at påpege relationen mellem design og overordnede diskussioner af...

  10. Physiologic adaptation changes of the "Bering Bridge" expedition participants.

    Science.gov (United States)

    Aidaraliyev, A A; Maximov, A L; Mala, T

    1993-04-01

    Cardiorespiratory measurements were repeatedly performed on indigenous and Caucasian Soviet and American male team members of the Bering Bridge expedition which covered approximately 1280 km over a 61 day period. Significant baseline differences in cardiorespiratory functions at rest and during submaximal cycle ergometer exercise were noted between racial groups. Indigenous members had significantly lower mean vital lung capacity and oxygen consumption levels during submaximal exercise, but a greater systolic blood pressure response to exercise. The energy cost during submaximal work decreased during the trek in both groups, but was marked in the Caucasians, suggesting that the indigenous subjects were better adapted at baseline to the Arctic environment. Overall, there was stabilization of functional responses in four of seven parameters studied, although differences between racial groups remained the same.

  11. beta-Endorphin immunoreactive material and authentic beta-endorphin in the plasma of males undergoing anaerobic exercise on a rowing ergometer.

    Science.gov (United States)

    Schulz, A; Harbach, H; Katz, N; Geiger, L; Teschemacher, H

    2000-10-01

    Adrenocorticotropic hormone (ACTH), beta-endorphin immunoreactive material (beta-endorphin IRM), and authentic beta-endorphin (1 -31) have been determined in the plasma of 23 volunteers undergoing anaerobic exercise on a rowing ergometer. The volunteers had different histories of training from occasional physical activities up to intensive preparation for international rowing competitions. ACTH and beta-endorphin-IRM were determined using commercially available immunometric assays; for determination of beta-endorphin (1-31) a highly specific two-site fluid phase immunoprecipitation radioimmunoassay was developed, which did not cross-react with any beta-endorphin derivative or any other opioid peptide tested. In agreement with reports from the literature ACTH and beta-endorphin-IRM concentrations in the plasma rose upon anaerobic exercise in all 23 subjects; this increase in the ACTH and beta-endorphin IRM levels was significantly correlated with the increase of lactate levels observed upon anaerobic exercise. Authentic beta-endorphin (1-31) was only found in two plasma samples containing minor concentrations of the peptide. We conclude that the beta-endorphin immunoreactive material released into blood under anaerobic exercise is identical with authentic beta-endorphin (1-31) only to a minor extent and thus should not be called "beta-endorphin". The major part of the material in fact released into the blood upon anaerobic exercise is probably identical with beta-lipotropin and further components so far unknown.

  12. Sub-maximal and maximal Yo-Yo intermittent endurance test level 2: heart rate response, reproducibility and application to elite soccer

    DEFF Research Database (Denmark)

    Bradley, Paul S; Mohr, Magni; Bendiksen, Mads

    2011-01-01

    The aims of this study were to (1) determine the reproducibility of sub-maximal and maximal versions of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2 test), (2) assess the relationship between the Yo-Yo IE2 test and match performance and (3) quantify the sensitivity of the Yo-Yo IE2 te......) in Yo-Yo IE2 test performance and heart rate after 6 min were 3.9% (n = 37) and 1.4% (n = 32), respectively. Elite male senior and youth U19 players Yo-Yo IE2 performances were better (P ...

  13. Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism

    DEFF Research Database (Denmark)

    Mourtzakis, M.; Graham, T.E.; Gonzalez-Alonso, J.

    2008-01-01

    Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops approximately 40-80% with the onset of exercise and 2-oxoglutarate...... declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70...... exercise under control conditions revealed a greater glutamate uptake in the T thigh compared with rest (7.3+/-3.7 vs. 1.0+/-0.1 micromol.min(-1).kg wet wt(-1), PTCA cycle intermediates. In the UT thigh, peak exercise (vs. rest) induced an increase in fumarate (0.33+/-0.07 vs. 0...

  14. Submaximal exercise testing with near-infrared spectroscopy in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients compared to healthy controls: a case-control study.

    Science.gov (United States)

    Miller, Ruth R; Reid, W Darlene; Mattman, Andre; Yamabayashi, Cristiane; Steiner, Theodore; Parker, Shoshana; Gardy, Jennifer; Tang, Patrick; Patrick, David M

    2015-05-20

    Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating illness. Symptoms include profound fatigue and distinctive post-exertional malaise (PEM). We asked whether a submaximal exercise test would prove useful for identifying different patterns of tissue oxygen utilization in individuals with ME/CFS versus healthy subjects. Such a test has potential to aid with ME/CFS diagnosis, or to characterize patients' illness. A case-control study of 16 patients with ME/CFS compared to 16 healthy controls completing a 3-min handgrip protocol was performed. Response was measured using near-infrared spectroscopy, resulting in measurements of oxygenated (O2Hb) and deoxygenated hemoglobin (HHb) over wrist extensors and flexors. Changes in O2Hb (delta (d)O2Hb) and HHb (dHHb) absorbance between the first and last contraction were calculated, as were the force-time product of all contractions, measured as tension-time index (TTI), and ratings of perceived exertion (RPE). Individuals with ME/CFS demonstrated smaller dO2Hb and dHHb than controls. However, after adjusting for TTI and change in total hemoglobin (delta (d)tHb), differences in dO2Hb and dHHb were reduced, with large overlapping variances. RPE was significantly higher for cases than controls, particularly at rest. Relative to controls, participants with ME/CFS demonstrated higher RPE, lower TTI, and reduced dO2Hb and dHHb during repetitive handgrip exercise, although considerable variance was observed. With further study, submaximal exercise testing may prove useful for stratifying patients with a lower propensity for inducing PEM, and have the ability to establish baseline intensities for exercise prescription.

  15. Reliability of a 5 x 6-s maximal cycling repeated-sprint test in trained female team-sport athletes.

    Science.gov (United States)

    McGawley, K; Bishop, D

    2006-11-01

    The present study examined the reliability of work and power measures during a 5 x 6-s cycle ergometer test of repeated-sprint ability. Nine, well-trained, female soccer players performed five, 5 x 6-s repeated-sprint tests on a front-access cycle ergometer on separate days. Sprints were separated by 24 s of active recovery. Absolute measures of total work done (W (tot)), total peak power (PP(tot)), work done during sprint 1 (W (1)) and peak power output during sprint 1 (PP(1)) were recorded. Decrement scores in work done (W (dec)) and peak power output (PP(dec)), and fatigue indices for work done (FI( W )) and peak power (FI( P )), were calculated. Significant improvements in all of the work and power measures were observed between trial 1 and subsequent trials (P x 6-s repeated-sprint cycling test. Furthermore, due to the large variation around performance decrement it was suggested that decrement scores ought to be interpreted with caution.

  16. The influence of training status, age, and muscle fiber type on cycling efficiency and endurance performance.

    Science.gov (United States)

    Hopker, James G; Coleman, Damian A; Gregson, Hannah C; Jobson, Simon A; Von der Haar, Tobias; Wiles, Jonathan; Passfield, Louis

    2013-09-01

    The purpose of this study was to assess the influence of age, training status, and muscle fiber-type distribution on cycling efficiency. Forty men were recruited into one of four groups: young and old trained cyclists, and young and old untrained individuals. All participants completed an incremental ramp test to measure their peak O2 uptake, maximal heart rate, and maximal minute power output; a submaximal test of cycling gross efficiency (GE) at a series of absolute and relative work rates; and, in trained participants only, a 1-h cycling time trial. Finally, all participants underwent a muscle biopsy of their right vastus lateralis muscle. At relative work rates, a general linear model found significant main effects of age and training status on GE (P type I muscle fibers was higher in the trained groups (P type and cycling efficiency at any work rate or cadence combination. Stepwise multiple regression indicated that muscle fiber type did not influence cycling performance (P > 0.05). Power output in the 1-h performance trial was predicted by average O2 uptake and GE, with standardized β-coefficients of 0.94 and 0.34, respectively, although some mathematical coupling is evident. These data demonstrate that muscle fiber type does not affect cycling efficiency and was not influenced by the aging process. Cycling efficiency and the percentage of type I muscle fibers were influenced by training status, but only GE at 120 revolutions/min was seen to predict cycling performance.

  17. Safe cycling!

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    The HSE Unit will be running a cycling safety campaign at the entrances to CERN's restaurants on 14, 15 and 16 May. Pop along to see if they can persuade you to get back in the saddle!   With summer on its way, you might feel like getting your bike out of winter storage. Well, the HSE Unit has come up with some original ideas to remind you of some of the most basic safety rules. This year, the prevention campaign will be focussing on three themes: "Cyclists and their equipment", "The bicycle on the road", and "Other road users". This is an opportunity to think about the condition of your bike as well as how you ride it. From 14 to 16 May, representatives of the Swiss Office of Accident Prevention and the Touring Club Suisse will join members of the HSE Unit at the entrances to CERN's restaurants to give you advice on safe cycling (see box). They will also be organising three activity stands where you can test your knowle...

  18. Energetics of best performances in track cycling.

    Science.gov (United States)

    Capelli, C; Schena, F; Zamparo, P; Monte, A D; Faina, M; di Prampero, P E

    1998-04-01

    VO2max and best performance times (BPTs) obtained during maximal voluntary trials over 1, 2, 5, and 10 km from a stationary start were assessed in 10 elite cyclists. Steady-state VO2 and peak blood lactate concentration ([La]b) were also determined in the same subjects pedaling on a track at constant submaximal speeds. The energy cost of cycling (Cc, J.m-1) was calculated as the ratio of VO2, corrected for glycolytic energy production and expressed in W, to v (m.s-1). Individual relationships between Cc and v were described by: Cc = Ccrr + k1 v2 where Ccrr is the energy spent against friction and k1 v2 is that spent against drag. Overall energy cost of cycling (Cctot) was obtained, adding to Cc the energy spent to accelerate the total moving mass from a stationary start. Individual theoretical BPTs were then calculated and compared with the actual ones as follows. The maximal metabolic power sustained at a constant level by a given subject (Emax, W) is a known function of the exhaustion time (te). It depends on his VO2max and maximal anaerobic capacity; it was obtained from individual VO2max and [La]b values. The metabolic power (Ec, W) necessary to cover any given distance (d) is a known function of the performance time over d (td); it is given by Ec = Cctot v = Cctot d td. For all subjects and distances, the t values solving the equalities Emax F(te) = Ec F(td) were calculated and assumed to yield theoretical BPTs. Calculations showed a fairly good agreement between actual and calculated BPTs with an average ratio of 1.035 +/- 0.058.

  19. Changes in oxygen uptake, shoulder muscles activity, and propulsion cycle timing during strenuous wheelchair exercise.

    Science.gov (United States)

    Bernasconi, S M; Tordi, N; Ruiz, J; Parratte, B

    2007-07-01

    Cross-over study. To determine the effect of strenuous wheelchair exercise on oxygen uptake (VO2 ), muscle activity and propulsion cycle timing (including the push time and recovery time during one full arm cycle). Laboratory of Sport Sciences at the University of France-Comte in France. Two exercise bouts of 6-min duration were performed at a constant workload: (1) non-fatigable exercise (moderate workload) and (2) fatigable exercise (heavy workload). Measurement of VO2, surface electromyographic activity (EMG) from shoulder muscles, and temporal parameters of wheelchair ergometer propulsion were collected from eight able-bodied men (26+/-4 years). A progressive increase in VO2 associated with EMG alterations (Pmuscle activation time (Pfatigue and inefficient muscle coordination, which may contribute to deleterious stress distributions at the shoulder joint, increasing susceptibility to injury.

  20. Effects of differentiated music on cycling time trial.

    Science.gov (United States)

    Lim, H B T; Atkinson, G; Karageorghis, C I; Eubank, M R; Eubank, M M

    2009-06-01

    The aim of this study was to investigate the effects of music introduced and removed during a 10-km cycling time trial with reference to Rejeski's parallel processing theory and Karageorghis, Terry and Lane's conceptual framework for the prediction of responses to asynchronous music during sub-maximal exercise. A range of performance variables, ratings of perceived exertion, positive affect, negative affect, and blood lactate were assessed. Eleven males (mean age=24.9, s=6.1 years) completed a 10-km time trial under three conditions; no music, music played initially then removed between 5-10 km, and music played between 5-10 km only. Variables of time, power, cadence, speed, RPE, blood lactate, positive and negative affect were analysed using a ConditionxDistance ANOVA. There was no significant main effect for music conditions for the performance variables, perceived exertion, blood lactate, and affect (p>0.05). Nevertheless, a significant interaction effect for ConditionxDistance was found for cycling speed, with participants cycling 1-1.25 km/h faster at the start of the music introduced time trial than in both the music removed and no music time trials (pmusic during exercise and this finding can be used to extend current theory as it does not specifically address the periodic use music. The fact that participants exercised harder when they expected music to be introduced at a later stage illustrates the behavioural influences that music can engender during self-paced exercise.

  1. The influence of recovery duration on multiple sprint cycling performance.

    Science.gov (United States)

    Glaister, Mark; Stone, Michael H; Stewart, Andrew M; Hughes, Michael; Moir, Gavin L

    2005-11-01

    The purpose of this study was to examine the influence of recovery duration on various measures of multiple sprint cycling performance. Twenty-five physically active men completed 2 maximal multiple sprint (20 x 5 seconds) cycling tests with contrasting recovery periods (10 or 30 seconds). The mean +/- SD values for age, height, and body mass were 20.6 +/- 1.5 years, 177.2 +/- 5.4 cm, and 78.2 +/- 8.2 kg, respectively. All tests were conducted on a friction-braked cycle ergometer. Longer (30 seconds) recovery periods resulted in significantly (p power output, the former appearing to result from a potentiation effect during the first few sprints. Thirty-second recovery periods also corresponded with significantly lower measures of fatigue (absolute difference: 16.1%; 95% likely range: 14.1-18.2%), heart rate, respiratory exchange ratio, and oxygen uptake. Blood lactate and ratings of perceived exertion (6-20 scale) increased progressively throughout both protocols and were significantly lower with 30-second recovery periods. The results of this study illustrate the considerable influence of recovery duration on various measures of multiple sprint work. Although the precise mechanisms of this response require further investigation, coaches and sport scientists should consider these findings when attempting to develop or evaluate the performance capabilities of athletes involved in multiple sprint sports.

  2. Abundance in proteins expressed after functional electrical stimulation cycling or arm cycling ergometry training in persons with chronic spinal cord injury.

    Science.gov (United States)

    Gorgey, Ashraf S; Graham, Zachary A; Bauman, William A; Cardozo, Christopher; Gater, David R

    2017-07-01

    Longitudinal design. The study determined the effects of two forms of exercise training on the abundance of two proteins, (glucose transporter-4 [GLUT-4], adenosine monophosphate kinase [AMPK]) involved in glucose utilization and the transcriptional coactivator that regulates the genes involved in energy metabolism and mitochondrial biogenesis (peroxisome proliferator-activated receptor (PPAR) coactivator 1 alpha [PGC-1α]), in muscles in men with chronic motor-complete spinal cord injury (SCI). Clinical trial at a Medical Center. Nine men with chronic motor-complete SCI participated in functional electrical stimulation lower extremity cycling (FES-LEC; n = 4) or arm cycling ergometer (arm-cycling ergometer [ACE]; n = 5) 5 days/week for 16 weeks. Whole body composition was measured by dual energy X-ray absorptiometry. An intravenous glucose tolerance test was performed to measure glucose effectiveness (Sg) and insulin sensitivity (Si). Muscle biopsies of the right vastus lateralis (VL) and triceps muscles were collected one week prior to and post the exercise training intervention. Neither training intervention altered body composition or carbohydrate metabolism. GLUT-4 increased by 3.8 fold in the VL after FES training and increased 0.6 fold in the triceps after ACE training. PGC-1α increased by 2.3 fold in the VL after FES training and 3.8 fold in the triceps after ACE training. AMPK increased by 3.4 fold in the VL after FES training and in the triceps after ACE training. FES-LEC and ACE training were associated with greater protein expressions in the trained muscles by effectively influencing the abundance of GLUT-4, AMPK and PGC-1α. Thus, FES-LEC training of paralyzed muscle can modulate protein expression similar to that of trained and innervated muscle.

  3. Cardiovascular drift and Vo2max during cycling and walking in a temperate environment.

    Science.gov (United States)

    Wingo, Jonathan E; Salaga, Laura J; Newlin, Mia K; Cureton, Kirk J

    2012-07-01

    Different muscle recruitment patterns during cycling and walking may influence the magnitude of cardiovascular drift (CV drift) during these respective modes of exercise, but whether this also influences the magnitude of reduced maximal oxygen uptake (Vo2max) associated with CV drift is unknown.This study tested the hypothesis that cycling results in greater CV drift and a greater decrement in Vo2max than walking in a temperate environment. CV drift was measured in nine recreationally active women (ages = 23 +/- 2 yr, Vo2max = 43.0 +/- 5.5 ml x kg(-1) x min(-1)) between 15 and 45 min of cycling or walking at 60% Vo2max on Separate occasions in 22 degrees C, 44% relative humidity. A graded exercise test to measure Vo2max was performed immediately after the submaximal exercise bout with no cessation of exercise. During separate trials involving each exercise mode, Vo2max was measured after 15 min of submaximal exercise so that changes in Vo2max between 15 and 45 min of exercise could be assessed between the same points in time in which CV drift occurred. Across both conditions, heart rate (HR) increased 5.4% and stroke volume (SV) decreased 11% from 15 to 45 min, but Vo2max was not significantly affected (7% reduction; 2.70 +/- 0.5 L min(-1) vs. 2.52 +/- 0.6 L min(-1)). In a temperate environment, a small CV drift corresponds to a small, non-significant decrease in Vo2max, regardless of whether the exercise performed is cycling or walking.

  4. Biomechanical changes elicited by an anterior cruciate ligament deficiency during steady rate cycling.

    Science.gov (United States)

    Hunt, Michael A; Sanderson, David J; Moffet, Hélène; Inglis, J Timothy

    2003-06-01

    To identify any changes to lower limb biomechanics during steady rate cycling as a result of an anterior cruciate ligament deficiency. Comparative study in which healthy and anterior cruciate ligament injured individuals underwent biomechanical analysis during stationary cycling. Individuals with an anterior cruciate ligament deficiency often exhibit reductions in the magnitude of quadriceps muscle activity and subsequent knee joint extensor moments during walking. It is not known whether these compensations are present during cycling, an exercise frequently used to retrain anterior cruciate ligament injured individuals. Ten healthy and 10 unilateral anterior cruciate ligament deficient individuals participated. All participants were required to cycle for approximately 30 s at each of six different cycling intensities while lower limb EMG, kinetics, and kinematics were collected bilaterally. Before riding, participants performed submaximal isometric contractions to generate normalizing data. In addition to reduced quadriceps activation and net knee joint extensor moments, the anterior cruciate ligament deficient limbs exhibited decreases in linear impulse of the resultant pedal force, knee joint flexor moments, hip and ankle extensor moments, and muscle activity from gluteus maximus. These decreases were counteracted by an increase in output from the anterior cruciate ligament intact limb. Anterior cruciate ligament injured individuals exhibited a limb attenuation strategy during cycling activities. This study reports lower limb kinetic and electromyographic data from anterior cruciate ligament deficient individuals during stationary cycling, and shows that these individuals exhibit a limb attenuation strategy on the very leg that is undergoing rehabilitation.

  5. The relationship between exercise-induced oxidative stress and the menstrual cycle.

    Science.gov (United States)

    Joo, Mi Hyun; Maehata, Eisuke; Adachi, Tetsuo; Ishida, Akiko; Murai, Fumie; Mesaki, Noboru

    2004-10-01

    The purpose of this study was to investigate the relationship between exercise-induced oxidative stress and the menstrual cycle in healthy sedentary woman. Eighteen women with regular menstrual cycles participated in this research. The subjects monitored their basal body temperature (BBT) and carried out a urinary ovulation test (twice) for 2 months prior to the study to determine their menstrual cycle. The subjects performed bicycle ergometer exercise (for 30 min at 60% V(.)>O(2max)) in each phase (menses, follicular and luteal phases) of the menstrual cycle. Serum estradiol and progesterone concentrations were determined from blood that was collected at rest. Serum thiobarbituric acid reactive substances (TBARS), total superoxide dismutase (T-SOD) and extracellular superoxide dismutase (EC-SOD) were determined as markers of oxidative stress in blood samples collected at rest and after exercise. TBARS was significantly lower after exercise [2.4 (0.5) nmol/ml] in the follicular phase, and T-SOD was significantly lower after exercise [3.2 (1.2) U/ml] in the luteal phase. EC-SOD did not show a significant change after exercise during each phase of the menstrual cycle. Furthermore, there was a negative correlation between estradiol and DeltaT-SOD ( r=-0.46, Pmenstrual cycle, free radicals produced as a consequence of exercise may be easily eliminated by sedentary women with normal menstrual cycles.

  6. Relationship between body and leg VO2 during maximal cycle ergometry

    Science.gov (United States)

    Knight, D. R.; Poole, D. C.; Schaffartzik, W.; Guy, H. J.; Prediletto, R.; Hogan, M. C.; Wagner, P. D.

    1992-01-01

    It is not known whether the asymptotic behavior of whole body O2 consumption (VO2) at maximal work rates (WR) is explained by similar behavior of VO2 in the exercising legs. To resolve this question, simultaneous measurements of body and leg VO2 were made at submaximal and maximal levels of effort breathing normoxic and hypoxic gases in seven trained male cyclists (maximal VO2, 64.7 +/- 2.7 ml O2.min-1.kg-1), each of whom demonstrated a reproducible VO2-WR asymptote during fatiguing incremental cycle ergometry. Left leg blood flow was measured by constant-infusion thermodilution, and total leg VO2 was calculated as the product of twice leg flow and radial arterial-femoral venous O2 concentration difference. The VO2-WR relationships determined at submaximal WR's were extrapolated to maximal WR as a basis for assessing the body and leg VO2 responses. The differences between measured and extrapolated maximal VO2 were 235 +/- 45 (body) and 203 +/- 70 (leg) ml O2/min (not significantly different). Plateauing of leg VO2 was associated with, and explained by, plateauing of both leg blood flow and O2 extraction and hence of leg VO2. We conclude that the asymptotic behavior of whole body VO2 at maximal WRs is a direct reflection of the VO2 profile at the exercising legs.

  7. Oxygen uptake kinetics and time to exhaustion in cycling and running: a comparison between trained and untrained subjects.

    Science.gov (United States)

    Caputo, F; Mello, M T; Denadai, B S

    2003-12-01

    The objective of the present study was to compare pulmonary gas exchange kinetics (VO2 kinetics) and time to exhaustion (Tlim) between trained and untrained individuals during severe exercise performed on a cycle ergometer and treadmill. Eleven untrained males in running (UR) and cycling (UC), nine endurance cyclists (EC), and seven endurance runners (ER) were submitted to the following tests on separate days: (i) incremental test for determination of maximal oxygen uptake (VO2max) and the intensity associated with the achievement of VO2max (IVO2max) on a mechanical braked cycle ergometer (EC and UC) and on a treadmill (ER and UR); (ii) all-out exercise bout performed at IVO2max to determine the time to exhaustion at IVO2max (Tlim) and the time constant of oxygen uptake kinetics (tau). The tau was significantly faster in trained group, both in cycling (EC = 28.2 +/- 4.7s; UC = 63.8 +/- 25.0s) and in running (ER = 28.5 +/- 8.5s; UR = 59.3 +/- 12.0s). Tlim of untrained was significantly lower in cycling (EC = 384.4 +/- 66.6s vs. UC; 311.1 +/- 105.7 s) and higher in running (ER = 309.2 +/- 176.6 s vs. UR = 439.8 +/- 104.2 s). We conclude that the VO2 kinetic response at the onset of severe exercise, carried out at the same relative intensity is sensitive to endurance training, irrespective of the exercise type. The endurance training seems to differently influence Tlim during exercise at IVO2max in running and cycling.

  8. Hydrological cycle.

    Science.gov (United States)

    Gonçalves, H C; Mercante, M A; Santos, E T

    2011-04-01

    The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water.

  9. The Effect of Upper Body Anaerobic Pre-Loading on 2000-m Ergometer-Rowing Performance in College Level Male Rowers

    Science.gov (United States)

    Purge, Priit; Hofmann, Peter; Merisaar, Rait; Mueller, Alexander; Tschakert, Gerhard; Mäestu, Jarek; Jürimäe, Jaak

    2017-01-01

    Elevated blood lactate has been shown to influence subsequent anaerobic exercise due to an inhibition of glycolysis. The aim of the present study was therefore to investigate the influence of a short and high-intensity anaerobic arm crank pre-load exercise (HIE) added to a low-intensity warm-up on cardio-respiratory and metabolic responses on a subsequent all out rowing exercise. Nine well-trained college level male rowers (24.6 ± 7.1 yrs; 1.87 ± 0.07 m; 88.9 ± 9.8 kg; 18.5 ± 3.7% body fat) volunteered to participate in the study. The subjects performed a maximal 2000-m rowing ergometer performance tests (MPT) twice. One MPT was preceded by a normal low intensity warm-up (MPTlow), while another one was performed with the additional inclusion of the HIE protocol (MPThigh). Overall rowing performance in the MPTlow was significantly faster (p = 0.004) by 3.7 ± 2.8 sec compared to the MPThigh condition (401.7 ± 23.0 s v. 405.4 ± 23.3 s) but the reduction in speed was found only for the first 1000-m (p = 0.017). Net La increase from rest to the end of the MPTlow was 11.9 ± 2.3 mmol·l-1 which was significantly higher (p = 0.0001) compared to the MPThigh condition (6.3 ± 1.8 mmol·l-1). Carbon dioxide output was significantly lower in the second (p = 0.041), third (p = 0.009), fourth (p = 0.036) and fifth (p = 0.028) 250-m split in the MPThigh compared to the MPTlow test. In conclusion, HIE upper-body anaerobic pre-load added to a standard low intensity warm-up protocol decreased anaerobic performance only in the early stages of the MPThigh but the latter part was unaffected. The inhibition of glycolysis in the first minute of the workout might allow a different race strategy, which needs to be investigated in further studies. Key points As blood lactate production can be inhibited to some extent, oxidative metabolism is favored which might be beneficial in some specific training sessions aiming to improve aerobic power. Despite a reduced performance in the 2000

  10. The Effect of Upper Body Anaerobic Pre-Loading on 2000-m Ergometer-Rowing Performance in College Level Male Rowers

    Directory of Open Access Journals (Sweden)

    Priit Purge, Peter Hofmann, Rait Merisaar, Alexander Mueller, Gerhard Tschakert, Jarek Mäestu, Jaak Jürimäe

    2017-06-01

    Full Text Available Elevated blood lactate has been shown to influence subsequent anaerobic exercise due to an inhibition of glycolysis. The aim of the present study was therefore to investigate the influence of a short and high-intensity anaerobic arm crank pre-load exercise (HIE added to a low-intensity warm-up on cardio-respiratory and metabolic responses on a subsequent all out rowing exercise. Nine well-trained college level male rowers (24.6 ± 7.1 yrs; 1.87 ± 0.07 m; 88.9 ± 9.8 kg; 18.5 ± 3.7% body fat volunteered to participate in the study. The subjects performed a maximal 2000-m rowing ergometer performance tests (MPT twice. One MPT was preceded by a normal low intensity warm-up (MPTlow, while another one was performed with the additional inclusion of the HIE protocol (MPThigh. Overall rowing performance in the MPTlow was significantly faster (p = 0.004 by 3.7 ± 2.8 sec compared to the MPThigh condition (401.7 ± 23.0 s v. 405.4 ± 23.3 s but the reduction in speed was found only for the first 1000-m (p = 0.017. Net La increase from rest to the end of the MPTlow was 11.9 ± 2.3 mmol·l-1 which was significantly higher (p = 0.0001 compared to the MPThigh condition (6.3 ± 1.8 mmol·l-1. Carbon dioxide output was significantly lower in the second (p = 0.041, third (p = 0.009, fourth (p = 0.036 and fifth (p = 0.028 250-m split in the MPThigh compared to the MPTlow test. In conclusion, HIE upper-body anaerobic pre-load added to a standard low intensity warm-up protocol decreased anaerobic performance only in the early stages of the MPThigh but the latter part was unaffected. The inhibition of glycolysis in the first minute of the workout might allow a different race strategy, which needs to be investigated in further studies.

  11. The Effect of Upper Body Anaerobic Pre-Loading on 2000-m Ergometer-Rowing Performance in College Level Male Rowers.

    Science.gov (United States)

    Purge, Priit; Hofmann, Peter; Merisaar, Rait; Mueller, Alexander; Tschakert, Gerhard; Mäestu, Jarek; Jürimäe, Jaak

    2017-06-01

    Elevated blood lactate has been shown to influence subsequent anaerobic exercise due to an inhibition of glycolysis. The aim of the present study was therefore to investigate the influence of a short and high-intensity anaerobic arm crank pre-load exercise (HIE) added to a low-intensity warm-up on cardio-respiratory and metabolic responses on a subsequent all out rowing exercise. Nine well-trained college level male rowers (24.6 ± 7.1 yrs; 1.87 ± 0.07 m; 88.9 ± 9.8 kg; 18.5 ± 3.7% body fat) volunteered to participate in the study. The subjects performed a maximal 2000-m rowing ergometer performance tests (MPT) twice. One MPT was preceded by a normal low intensity warm-up (MPTlow), while another one was performed with the additional inclusion of the HIE protocol (MPThigh). Overall rowing performance in the MPTlow was significantly faster (p = 0.004) by 3.7 ± 2.8 sec compared to the MPThigh condition (401.7 ± 23.0 s v. 405.4 ± 23.3 s) but the reduction in speed was found only for the first 1000-m (p = 0.017). Net La increase from rest to the end of the MPTlow was 11.9 ± 2.3 mmol·l-1 which was significantly higher (p = 0.0001) compared to the MPThigh condition (6.3 ± 1.8 mmol·l-1). Carbon dioxide output was significantly lower in the second (p = 0.041), third (p = 0.009), fourth (p = 0.036) and fifth (p = 0.028) 250-m split in the MPThigh compared to the MPTlow test. In conclusion, HIE upper-body anaerobic pre-load added to a standard low intensity warm-up protocol decreased anaerobic performance only in the early stages of the MPThigh but the latter part was unaffected. The inhibition of glycolysis in the first minute of the workout might allow a different race strategy, which needs to be investigated in further studies.

  12. Effects of acute caffeinated coffee consumption on energy utilization related to glucose and lipid oxidation from short submaximal treadmill exercise in sedentary men.

    Science.gov (United States)

    Leelarungrayub, Donrawee; Sallepan, Maliwan; Charoenwattana, Sukanya

    2011-01-01

    Aim of this study was to evaluate the short term effect of coffee drinking on energy utilization in sedentary men. This study was performed in healthy sedentary men, who were randomized into three groups, control (n = 6), decaffeinated (n = 10), and caffeine (n = 10). The caffeine dose in coffee was rechecked and calculated for individual volunteers at 5 mg/kg. Baseline before drinking, complete blood count (CBC), glucose, antioxidant capacity, lipid peroxide, and caffeine in blood was evaluated. After drinking coffee for 1 hr, the submaximal exercise test with a modified Bruce protocol was carried out, and the VO2 and RER were analyzed individually at 80% maximal heart rate, then the blood was repeat evaluated. Three groups showed a nonsignificant difference in CBC results and physical characteristics. The caffeine group showed significant changes in all parameters; higher VO2 levels, (P = 0.037) and lower RER (P = 0.047), when compared to the baseline. Furthermore, the glucose level after exercise test increased significantly (P = 0.033) as well as lipid peroxide levels (P = 0.005), whereas antioxidant capacity did not change significantly (P = 0.759), when compared to the before exercise testing. In addition, the blood caffeine level also increased only in the caffeine group (P = 0.008). Short consumption of caffeinated coffee (5 mg/kg of caffeine), improves energy utilization and relates to glucose derivation and lipid oxidation.

  13. The Effect of Submaximal Exercise Preceded by Single Whole-Body Cryotherapy on the Markers of Oxidative Stress and Inflammation in Blood of Volleyball Players

    Science.gov (United States)

    Mila-Kierzenkowska, Celestyna; Szpinda, Michał; Augustyńska, Beata; Woźniak, Bartosz

    2013-01-01

    The aim of the study was to determine the effect of single whole-body cryotherapy (WBC) session applied prior to submaximal exercise on the activity of antioxidant enzymes, the concentration of lipid peroxidation products, total oxidative status, and the level of cytokines in blood of volleyball players. The study group consisted of 18 male professional volleyball players, who were subjected to extremely cold air (−130°C) prior to exercise performed on cycloergometer. Blood samples were taken five times: before WBC, after WBC procedure, after exercise preceded by cryotherapy (WBC exercise), and before and after exercise without WBC (control exercise). The activity of catalase statistically significantly increased after control exercise. Moreover, the activity of catalase and superoxide dismutase was lower after WBC exercise than after control exercise (P cryotherapy prior to exercise may have some antioxidant and anti-inflammatory properties. The relations between the level of studied oxidative stress and inflammatory markers may testify to the contribution of reactive oxygen species in cytokines release into the blood system in response to exercise and WBC. PMID:24489985

  14. The Effect of Submaximal Exercise Preceded by Single Whole-Body Cryotherapy on the Markers of Oxidative Stress and Inflammation in Blood of Volleyball Players

    Directory of Open Access Journals (Sweden)

    Celestyna Mila-Kierzenkowska

    2013-01-01

    Full Text Available The aim of the study was to determine the effect of single whole-body cryotherapy (WBC session applied prior to submaximal exercise on the activity of antioxidant enzymes, the concentration of lipid peroxidation products, total oxidative status, and the level of cytokines in blood of volleyball players. The study group consisted of 18 male professional volleyball players, who were subjected to extremely cold air (−130∘C prior to exercise performed on cycloergometer. Blood samples were taken five times: before WBC, after WBC procedure, after exercise preceded by cryotherapy (WBC exercise, and before and after exercise without WBC (control exercise. The activity of catalase statistically significantly increased after control exercise. Moreover, the activity of catalase and superoxide dismutase was lower after WBC exercise than after control exercise (P<0.001. After WBC exercise, the level of IL-6 and IL-1β was also lower (P<0.001 than after control exercise. The obtained results may suggest that cryotherapy prior to exercise may have some antioxidant and anti-inflammatory properties. The relations between the level of studied oxidative stress and inflammatory markers may testify to the contribution of reactive oxygen species in cytokines release into the blood system in response to exercise and WBC.

  15. The influence of endurance training on multiple sprint cycling performance.

    Science.gov (United States)

    Glaister, Mark; Stone, Michael H; Stewart, Andrew M; Hughes, Michael G; Moir, Gavin L

    2007-05-01

    The aims of the present study were to examine the effects of endurance training on multiple sprint cycling performance and to evaluate the influence of recovery duration on the magnitude of those effects. Twenty-one physically active male university students were randomly assigned to either an experimental (n = 12) or a control (n = 9) group. The experimental group cycled for 20 minutes each day, 3 times per week, for 6 weeks at 70% of the power output required to elicit maximal oxygen uptake (VO2max). Multiple sprint performance was assessed using 2 maximal (20 x 5 seconds) sprint cycling tests with contrasting recovery periods (10 or 30 seconds). All tests were conducted on a friction-braked cycle ergometer. Relative to controls, training resulted in a 0.2 L.min(-1) increase in mean VO2max (95% likely range: -0.04 to 0.44 L.min(-1)). Changes in anaerobic capacity (determined by maximal accumulated oxygen deficit) over the same period were trivial (p = 0.96). After training, the experimental group showed significant improvements ( approximately 40 W), relative to controls, in multiple sprint measures of peak and mean power output. In contrast, training-induced reductions in fatigue were trivial (p = 0.63), and there were no significant between-protocol differences in the magnitude of any effects. In summary, 6 weeks of endurance training resulted in substantial improvements in multiple sprint cycling performance, the magnitude of the improvements being largely unaffected by the duration of the intervening recovery periods.

  16. Neuromuscular adjustments of the quadriceps muscle after repeated cycling sprints.

    Directory of Open Access Journals (Sweden)

    Olivier Girard

    Full Text Available PURPOSE: This study investigated the supraspinal processes of fatigue of the quadriceps muscle in response to repeated cycling sprints. METHODS: Twelve active individuals performed 10 × 6-s "all-out" sprints on a cycle ergometer (recovery = 30 s, followed 6 min later by 5 × 6-s sprints (recovery = 30 s. Transcranial magnetic and electrical femoral nerve stimulations during brief (5-s and sustained (30-s isometric contractions of the knee extensors were performed before and 3 min post-exercise. RESULTS: Maximal strength of the knee extensors decreased during brief and sustained contractions (~11% and 9%, respectively; P0.05. While cortical voluntary activation declined (P 40% reduced (P<0.001 following exercise. CONCLUSION: The capacity of the motor cortex to optimally drive the knee extensors following a repeated-sprint test was shown in sustained, but not brief, maximal isometric contractions. Additionally, peripheral factors were largely involved in the exercise-induced impairment in neuromuscular function, while corticospinal excitability was well-preserved.

  17. VARIATION IN RESISTIVE FORCE SELECTION DURING BRIEF HIGH INTENSITY CYCLE ERGOMETRY: IMPLICATIONS FOR POWER ASSESSMENT AND PRODUCTION IN ELITE KARATE PRACTITIONERS

    Directory of Open Access Journals (Sweden)

    Julien Steven Baker

    2006-07-01

    Full Text Available The purpose of this study was to measure power values generated in elite karate fighters during brief high intensity cycle ergometry when resistive forces were derived from total - body mass (TBM or fat - free mass (FFM. Male international karate practitioners volunteered as participants (n = 11. Body density was calculated using hydrostatic weighing procedures with fat mass ascertained from body density values. Participants were required to pedal maximally on a cycle ergometer (Monark 864 against randomly assigned loads ranging from 70 g·kg-1 - 95 g·kg-1 (using a TBM or FFM protocol for 8 seconds. The resistive force that produced the highest peak power output (PPO for each protocol was considered optimal. Differences (p 0.05 were observed between time to PPO, or heart rate when the TBM and FFM protocols were compared. The findings of this study suggest that when high intensity cycle ergometer resistive forces are derived from FFM, greater peak powers can be obtained consistently in karate athletes. Resistive forces that relate to the active muscle tissue utilised during this type of exercise may need to be explored in preference to protocols that include both lean and fat masses. The findings have implications for both exercise prescription and the evaluation of experimental results concerning karate athletes

  18. Indexes of power and aerobic capacity obtained in cycle ergometry and treadmill running: comparisons between sedentary, runners, cyclists and triathletes

    Directory of Open Access Journals (Sweden)

    Fabrizio Caputo

    2003-08-01

    Full Text Available The objectives of this study were: a to determine, in a cross-sectional manner, the effect of aerobic training on the peak oxygen uptake (O2peak, the intensity at O2peak (IO2peak and the anaerobic threshold (AnT during running and cycling; and b to verify if the transference of the training effects are dependent on the analized type of exercise or physiological index. Eleven untrained males (UN, nine endurance cyclists (EC, seven endurance runners (ER, and nine triathletes (TR were submitted, on separate days, to incremental tests until voluntary exhaustion on a mechanical braked cycle ergometer and on a treadmill. The values of O2peak (ml.kg-1.min-1 obtained in running and cycle ergometer (ER = 68.8 ± 6.3 and 62.0 ± 5.0; EC = 60.5 ± 8.0 and 67.6 ± 7.6; TR = 64.5 ± 4.8 and 61.0 ± 4.1; UN = 43.5 ± 7.0 and 36.7 ± 5.6; respectively were higher in the group that presented specific training in the modality. The UN group presented the lower values of O2peak, regardless of the type of exercise. This same behavior was observed for the AnT (ml.kg-1.min-1 determined in running and cycle ergometer (ER = 56.8 ± 6.9 and 44.8 ± 5.7; EC = 51.2 ± 5.2 and 57.6 ± 7.1; TR = 56.5 ± 5.1 and 49.0 ± 4.8; UN = 33.2 ± 4.2 and 22.6 ± 3.7; respectively. It can be concluded that the transference of the training effects seems to be only partial, independently of the index (O2peak, IO2peak or AnT or exercise type (running or cycling. In relation to the indices, the specificity of training seems to be less present in the O2peak than in the IO2peak and the AnT.

  19. Estimate of the 3,5 MMOL.L-¹ lactate threshold by maximal and submaximal variables during treadmill incremental test

    Directory of Open Access Journals (Sweden)

    Maria Kiss

    2006-03-01

    Full Text Available In predictive models, there is a lack of studies that have associated maximal and submaximal variables to attain lactate threshold (LT. Therefore, the purpose of this paper was to investigate the possibility for predicting 3.5 mmol.l-1 LT velocity (V3.5 using maximal and submaximal variables. The heart rate (HR corresponding to 12 km.h-1 velocity (HR12, the peak heart rate (HRPEAK, the velocity corresponding to HR of 170 bpm (V170 and the peak velocity (VPEAK were the independent variables used. Forty-six runners underwent to progressive test with initial velocity between 6 and 10.8 km.h-1, and increments of 1.2 km.h-1 every three minutes. The subjects were randomly assigned to validation group (n= 30 or cross-validation group (n= 16. Multiple regression analysis (Enter selection resulted in the following predictive equation (p RESUMO Em modelos preditivos, há uma ausência de estudos que tenham associado variáveis máximas e submáximas para a obtenção dos limiares de lactato. Desta maneira, o objetivo deste estudo foi verificar a possibilidade de estimativa do limiar de lactato, referente à concentração de lactato sangüíneo de 3,5 mmol.l-1 (LL3,5, a partir de variáveis máximas e submáximas obtidas em protocolo progressivo, em esteira rolante. Como variáveis preditoras, foram utilizadas a freqüência cardíaca (FC referente à velocidade de 12 km.h-1 (FC12, a FC de pico (FCPICO, a velocidade correspondente à FC de 170 bpm (VEL170 e a velocidade de pico (VELPICO. Após executar protocolo progressivo, com velocidade inicial entre 6,0 e 10,8 km.h-1, e incrementos de 1,2 km.h-1 a cada estágio de 3 minutos 5, 46 atletas aeróbios foram divididos aleatoriamente em grupo de validação (n= 30 e grupo de validação cruzada (n= 16. A análise de regressão múltipla (método Enter resultou na seguinte equação de predição (p< 0,05: LL3,5 (km.h1= -3,650 + (1,042 x VELPICO, com EPE de 1,2 km.h1 (7,7% e R² de 0,74. Não houve diferen

  20. Graded Cycling Test Combined With the Talk Test Is Responsive in Cardiac Rehabilitation

    DEFF Research Database (Denmark)

    Nielsen, Susanne Grøn; Vinther, Anders

    2016-01-01

    combined with the Graded Cycling Test (GCT-TT) in cardiac patients. The purpose was to investigate responsiveness of GCT-TT in cardiac rehabilitation patients. METHODS: Patients (n = 93) referred to 8 weeks of cardiac rehabilitation were included. Pre- and posttests were performed using GCT-TT. Mean test......PURPOSE: To evaluate clinical assessment outcome of cardiac rehabilitation, a simple and reliable submaximal exercise test, not based on heart rate, is warranted. The Talk Test (TT) has been found to correlate well with the ventilatory threshold, and excellent reliability was observed for TT...... changes in watts (W) were compared with the standard error of measurement (SEM95) for groups and the smallest real difference (SRD) for individuals. Minimal clinically important difference was assessed by comparing patient perceived changes in physical fitness with the test changes. RESULTS...

  1. Effects of the menstrual cycle on excess postexercise oxygen consumption in healthy young women.

    Science.gov (United States)

    Matsuo, T; Saitoh, S; Suzuki, M

    1999-03-01

    The effects of the menstrual cycle on excess postexercise oxygen consumption (EPOC) were studied in seven healthy young women aged 18 to 20 years. EPOC, resting metabolic rate (RMR), and energy expenditure during exercise (EEDE) in the fasting state were measured in the follicular and luteal phases. On the experimental days, subjects exercised for 60 minutes on a bicycle ergometer at an intensity of 60% maximal oxygen consumption (VO2max) followed by rest for 6 hours. The EPOC and RMR were significantly higher (P < .05) and the postexercise respiratory exchange ratio (RER) was significantly lower (P < .05) in the luteal phase versus the follicular phase, whereas differences in the EEDE and basal and exercise RER were negligible in both phases. Fat oxidation during the experimental period was significantly greater in the luteal phase (P < .05). These results suggest that exercise in the luteal phase results in greater postexercise energy expenditure and fat utilization than in the follicular phase.

  2. Predictive Dynamic Simulation of Seated Start-Up Cycling Using Olympic Cyclist and Bicycle Models

    Directory of Open Access Journals (Sweden)

    Conor Jansen

    2018-02-01

    Full Text Available Predictive dynamic simulation is a useful tool for analyzing human movement and optimizing performance. Here it is applied to Olympic-level track cycling. A seven degree-of-freedom, two-legged cyclist and bicycle model was developed using MapleSim. GPOPS-II, a direct collocation optimal control software, was used to solve the optimal control problem for the predictive simulation. The model was validated against ergometer pedaling performed by seven Olympic-level track cyclists from the Canadian team. The simulations produce joint angles and cadence/torque/power similar to experimental results. The results indicate optimal control can be used for predictive simulation with a combined cyclist and bicycle model. Future work needed to more accurately model an Olympic cyclist and a standing start is discussed.

  3. The effect of time trial cycling position on physiological and aerodynamic variables.

    Science.gov (United States)

    Fintelman, D M; Sterling, M; Hemida, H; Li, F-X

    2015-01-01

    To reduce aerodynamic resistance cyclists lower their torso angle, concurrently reducing Peak Power Output (PPO). However, realistic torso angle changes in the range used by time trial cyclists have not yet been examined. Therefore the aim of this study was to investigate the effect of torso angle on physiological parameters and frontal area in different commonly used time trial positions. Nineteen well-trained male cyclists performed incremental tests on a cycle ergometer at five different torso angles: their preferred torso angle and at 0, 8, 16 and 24°. Oxygen uptake, carbon dioxide expiration, minute ventilation, gross efficiency, PPO, heart rate, cadence and frontal area were recorded. The frontal area provides an estimate of the aerodynamic drag. Overall, results showed that lower torso angles attenuated performance. Maximal values of all variables, attained in the incremental test, decreased with lower torso angles (P aerodynamic drag and physiological functioning.

  4. No effect of menstrual cycle phase on fuel oxidation during exercise in rowers.

    Science.gov (United States)

    Vaiksaar, Sille; Jürimäe, Jaak; Mäestu, Jarek; Purge, Priit; Kalytka, Svetlana; Shakhlina, Larissa; Jürimäe, Toivo

    2011-06-01

    The aim of this investigation was to examine the effects of menstrual cycle phase on substrate oxidation and lactate concentration during exercise. Eleven eumenorrheic female rowers (18.4 ± 1.9 years; 172.0 ± 4.0 cm; 67.2 ± 8.4 kg; 27.7 ± 4.8% body fat) completed 1 h rowing ergometer exercise at 70% of maximal oxygen consumption (VO(2max)) during two different phases of the menstrual cycle: the follicular phase (FP) and the luteal phase (LP). Resting and exercise measurements of the whole body energy expenditure, oxygen consumption (VO(2)), respiratory exchange ratio (RER), substrate oxidation and lactate blood levels were made. Energy expenditure, VO(2) and heart rate during the 1-h exercise were not significantly different (P > 0.05) among menstrual cycle phases. Resting RER and RER during the entire 1 h exercise period were not significantly different among menstrual cycle phases. There was an increase (P menstrual cycle phases. Blood lactate concentrations significantly increased in the transition between rest and exercise and remained relatively constant during the whole 1 h of exercise in both menstrual cycle phases. No menstrual cycle phase effect (P > 0.05) was observed for blood lactate concentrations. In conclusion, our results demonstrated no effect of menstrual cycle phase on substrate oxidation and blood lactate concentration during rowing exercise at 70% of VO(2max) in athletes. Normally menstruating female rowers should not be concerned about their menstrual cycle phase with regard to substrate oxidation in everyday training.

  5. Essays on economic cycles

    NARCIS (Netherlands)

    Groot, de E.A. (Bert)

    2006-01-01

    Schumpeter’s line of thought of multiple economic cycles is further investigated. The existence of multiple cycles in economic variables is demonstrated. In basic innovations five different cycles are found. Multiple cycle structures are shown in various macro-economic variables from the United

  6. Aerobic and anaerobic correlates of multiple sprint cycling performance.

    Science.gov (United States)

    Glaister, Mark; Stone, Michael H; Stewart, Andrew M; Hughes, Michael G; Moir, Gavin L

    2006-11-01

    The aims of this study were to examine (a) the relationship between maximal oxygen uptake (VO(2)max) and several performance indices of multiple sprint cycling; (b) the relationship between maximal accumulated oxygen deficit (MAOD) and those same performance indices; and (c) the influence of recovery duration on the magnitude of those relationships. Twenty-five physically active men completed a VO(2)max test, a MAOD test, and 2 maximal intermittent (20 x 5 seconds) sprint cycling tests with contrasting recovery periods (10 seconds or 30 seconds). Mean +/- SD for age, height, and body mass were 20.6 +/- 1.5 years, 177.2 +/- 5.4 cm, and 78.2 +/- 8.2 kg, respectively. All tests were conducted on a friction-braked cycle ergometer with subsequent data normalized for body mass. Moderate (0.3 power output data and MAOD (range, 0.31-0.46; 95% confidence limits, -0.10 to 0.72). Moderate to large positive correlations also were observed between power output data and VO(2)max, the magnitude of which increased as values were averaged across all sprints (range, 0.45-0.67; 95% confidence limits 0.07-0.84). Correlations between fatigue and VO(2)max were greater in the intermittent protocol with 30-second recovery periods (r = -0.34; 95% confidence limits, 0.06 to -0.65). The results of this study reflect the complex energetics associated with multiple sprint work. Though the findings add support to the idea that multiple sprint sports demand a combination of speed and endurance, further longitudinal research is required to confirm the relative importance of these parameters.

  7. Quadriceps and hamstring muscle activity during cycling as measured with intramuscular electromyography.

    Science.gov (United States)

    da Silva, Julio Cézar Lima; Tarassova, O; Ekblom, M M; Andersson, E; Rönquist, G; Arndt, A

    2016-09-01

    The aim of this study was to describe thigh muscle activation during cycling using intramuscular electromyographic recordings of eight thigh muscles, including the biceps femoris short head (BFS) and the vastus intermedius (Vint). Nine experienced cyclists performed an incremental test (start at 170 W and increased by 20 W every 2 min) on a bicycle ergometer either for a maximum of 20 min or to fatigue. Intramuscular electromyography (EMG) of eight muscles and kinematic data of the right lower limb were recorded during the last 20 s in the second workload (190 W). EMG data were normalized to the peak activity occurring during this workload. Statistical significance was assumed at p ≤ 0.05. The vastii showed a greater activation during the 1st quadrant compared to other quadrants. The rectus femoris (RF) showed a similar activation, but with two bursts in the 1st and 4th quadrants in three subjects. This behavior may be explained by the bi-articular function during the cycling movement. Both the BFS and Vint were activated longer than, but in synergy with their respective agonistic superficial muscles. Intramuscular EMG was used to verify muscle activation during cycling. The activation pattern of deep muscles (Vint and BFS) could, therefore, be described and compared to that of the more superficial muscles. The complex coordination of quadriceps and hamstring muscles during cycling was described in detail.

  8. Modulating effects of the menstrual cycle on cardiorespiratory responses to exercise under acute hypobaric hypoxia.

    Science.gov (United States)

    Takase, Kazuko; Nishiyasu, Takeshi; Asano, Katsumi

    2002-12-01

    The purpose of this study was to examine the hypothesis that the menstrual cycle-induced modulation of the cardiorespiratory response to exercise might be altered by acute exposure to altitude. During both the luteal and follicular phases, 9 moderately trained female subjects with normal menstrual cycles performed incremental exercise to maximal effort on a cycle ergometer at sea level (SL) and under hypobaric hypoxia (HH) at the equivalent of 3,000 m altitude. Both at rest and during exercise, minute ventilation (.VE) and oxygen uptake (.VO(2)) did not differ between the luteal and follicular phases (either at SL or HH). However, the ratio of .VE to .VO(2) (.VE /.VO(2)), both at rest and during peak exercise, was greater in the luteal phase than in the follicular phase under HH conditions. Furthermore, the partial pressure of end-tidal carbon dioxide (PETCO(2)) during exercise was lower in the luteal phase than in the follicular phase in HH. These results suggest that the menstrual cycle-induced modulation of the ventilatory response to exercise may be altered under acute hypobaric-hypoxic conditions.

  9. Substrate oxidation at rest and during exercise: effects of menstrual cycle phase and diet composition.

    Science.gov (United States)

    Wenz, M; Berend, J Z; Lynch, N A; Chappell, S; Hackney, A C

    1997-12-01

    The estrogen hormones have been shown to be highly glycogenic as well as lipolytic in nature. It is unknown whether the metabolic actions of estrogens impact upon energy metabolism during exercise. The composition of prior diet, however, does affect exercise energy metabolism. This study examined the influence of menstrual cycle phase (mid-follicular [FP; low estrogen] vs. mid-luteal [LP; high estrogen]) and diet composition on the rate of substrate oxidation for carbohydrate (CHO) and lipid at rest and during various intensities of physical exercise. Nine subjects completed an experimental session under four different menstrual cycle-diet conditions: 1) FP following a 3-day high CHO diet [75% total caloric intake], 2) FP following a 3-day low CHO diet [35% total caloric intake], 3) LP following a 3-day high CHO diet, and 4) LP following a 3-day low CHO diet. In each of the experimental sessions substrate oxidation was determined at rest and during cycle ergometer exercise at intensities of 30, 50, and 70% VO2max, respectively. Statistically significant (p menstrual cycle phase and diet conditions were found at rest and during 30%-50% exercise. In general, CHO oxidation was lowest and lipid oxidation highest in the LP under a low CHO diet condition.

  10. Morning-to-evening differences in oxygen uptake kinetics in short-duration cycling exercise.

    Science.gov (United States)

    Brisswalter, Jeanick; Bieuzen, François; Giacomoni, Magali; Tricot, Véronique; Falgairette, Guy

    2007-01-01

    This study analyzed diurnal variations in oxygen (O(2)) uptake kinetics and efficiency during a moderate cycle ergometer exercise. Fourteen physically active diurnally active male subjects (age 23+/-5 yrs) not specifically trained at cycling first completed a test to determine their ventilatory threshold (T(vent)) and maximal oxygen consumption (VO(2max)); one week later, they completed four bouts of testing in the morning and evening in a random order, each separated by at least 24 h. For each period of the day (07:00-08:30 h and 19:00-20:30 h), subjects performed two bouts. Each bout was composed of a 5 min cycling exercise at 45 W, followed after 5 min rest by a 10 min cycling exercise at 80% of the power output associated with T(vent). Gas exchanges were analyzed breath-by-breath and fitted using a mono-exponential function. During moderate exercise, the time constant and amplitude of VO(2) kinetics were significantly higher in the morning compared to the evening. The net efficiency increased from the morning to evening (17.3+/-4 vs. 20.5+/-2%; pevening (+34%; ptime of day and could be related to variability in muscle activity pattern.

  11. Effect of blood haemoglobin concentration on V(O2,max) and cardiovascular function in lowlanders acclimatised to 5260 m

    DEFF Research Database (Denmark)

    Calbet, J A L; Rådegran, G; Boushel, Robert Christopher

    2002-01-01

    of cardiac output (CO), blood pressure and muscular blood flow (LBF) during exercise. Eight Danish lowlanders (three females and five males; 24 +/- 0.6 years, mean +/- S.E.M.) performed submaximal and maximal exercise on a cycle ergometer after 9 weeks at an altitude of 5260 m (Mt Chacaltaya, Bolivia......)) and the measurements were repeated, increasing the work rate as tolerated. Hyperoxia increased maximal power output and leg V(O(2),max), showing that breathing ambient air at 5260 m, V(O(2),max) is limited by the availability of O(2) rather than by muscular oxidative capacity. Altitude increased [Hb] by 36 % from 136...

  12. DIURNAL VARIATION OF HAEMOSTATIC RESPONSE TO EXERCISE IN YOUNG SEDENTARY MALES

    OpenAIRE

    Marefat Siahkouhian; Davar Khodadadi; Lotfali Bolboli

    2013-01-01

    The aim of this study was to evaluate diurnal variations in the haemostatic response to submaximal exercise performed by young, sedentary men. Fifteen healthy young sedentary males aged 25.6 ± 1.34 (mean ± SD) years performed two exercise sessions, morning and evening, at 70% of maximal oxygen consumption ( V . O2max) on a cycle ergometer for 30 min. Platelet count (PC), activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, tissue plasminogen activator (tPA) and pla...

  13. Solar Cycle 25: Another Moderate Cycle?

    Science.gov (United States)

    Cameron, R. H.; Jiang, J.; Schüssler, M.

    2016-06-01

    Surface flux transport simulations for the descending phase of Cycle 24 using random sources (emerging bipolar magnetic regions) with empirically determined scatter of their properties provide a prediction of the axial dipole moment during the upcoming activity minimum together with a realistic uncertainty range. The expectation value for the dipole moment around 2020 (2.5 ± 1.1 G) is comparable to that observed at the end of Cycle 23 (about 2 G). The empirical correlation between the dipole moment during solar minimum and the strength of the subsequent cycle thus suggests that Cycle 25 will be of moderate amplitude, not much higher than that of the current cycle. However, the intrinsic uncertainty of such predictions resulting from the random scatter of the source properties is considerable and fundamentally limits the reliability with which such predictions can be made before activity minimum is reached.

  14. Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism.

    Science.gov (United States)

    Mourtzakis, M; Graham, T E; González-Alonso, J; Saltin, B

    2008-08-01

    Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops approximately 40-80% with the onset of exercise and 2-oxoglutarate declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). After 5 wk of training, peak oxygen consumption (VO2peak) in the T thigh was greater than that in the UT thigh (PTCA cycle intermediates. In the UT thigh, peak exercise (vs. rest) induced an increase in fumarate (0.33+/-0.07 vs. 0.02+/-0.01 mmol/kg dry wt (dw), PTCA cycle, glutamate and TCA cycle intermediates do not directly affect VO2peak in either trained or untrained muscle.

  15. Cycling in Sydney, Australia

    Directory of Open Access Journals (Sweden)

    Alexis Zander

    2013-01-01

    Full Text Available Introduction. Cycling can be an enjoyable way to meet physical activity recommendations and is suitable for older people; however cycling participation by older Australians is low. This qualitative study explored motivators, enablers, and barriers to cycling among older people through an age-targeted cycling promotion program. Methods. Seventeen adults who aged 50–75 years participated in a 12-week cycling promotion program which included a cycling skills course, mentor, and resource pack. Semistructured interviews at the beginning and end of the program explored motivators, enablers, and barriers to cycling. Results. Fitness and recreation were the primary motivators for cycling. The biggest barrier was fear of cars and traffic, and the cycling skills course was the most important enabler for improving participants’ confidence. Reported outcomes from cycling included improved quality of life (better mental health, social benefit, and empowerment and improved physical health. Conclusions. A simple cycling program increased cycling participation among older people. This work confirms the importance of improving confidence in this age group through a skills course, mentors, and maps and highlights additional strategies for promoting cycling, such as ongoing improvement to infrastructure and advertising.

  16. The Effect of 4 Weeks Fixed and Mixed Intermittent Hypoxic Training (IHT) on Respiratory Metabolic and Acid-base Response of Capillary Blood During Submaximal Bicycle Exercise in Male Elite Taekwondo Players.

    Science.gov (United States)

    Park, Hun-Young; Sunoo, Sub; Nam, Sang-Seok

    2016-12-31

    The purpose of our study was to determine the effectiveness of 4 weeks fixed and mixed intermittent hypoxic training (IHT) and its difference from exercise training at sea-level on exercise load, respiratory metabolic and acid-base response of capillary blood during 80% maximal heart rate (HRmax) bicycle exercise in male elite Taekwondo players. Male elite Taekwondo players (n = 25 out of 33) were randomly assigned to training at sea-level (n = 8, control group), training at 16.5%O 2 (2000 m) simulated hypoxic condition (n = 9, fixed IHT group), and training at 14.5%O 2 (3000 m) up to 2 weeks and 16.5%O 2 (2000 m) simulated hypoxic condition (n = 8, mixed IHT group) for 3 weeks. We compared their average exercise load, respiratory metabolic, and acid-base response of the capillary blood during 80% HRmax submaximal bicycle exercise before and after 4 weeks training. Fixed and mixed IHT groups showed positive improvement in respiratory metabolic and acid-base response of the capillary blood during 80% HRmax submaximal bicycle exercise after 4 weeks training. However, all dependent variables showed no significant difference between fixed IHT and mix IHT. Results suggested that mixed and fixed IHT is effective in improving respiratory metabolic and acid-base response of capillary blood in male elite Taekwondo players. Thus, IHT could be a novel and effective method for improving exercise performance through respiratory metabolic and acid-base response.

  17. The science of cycling: physiology and training - part 1.

    Science.gov (United States)

    Faria, Erik W; Parker, Daryl L; Faria, Irvin E

    2005-01-01

    ' system serves to set the tolerable upper limits of competitive effort in order to assure the athlete completion of the physical challenge. Physiological markers found to be predictive of cycling performance include: (i) power output at the lactate threshold (LT2); (ii) peak power output (W(peak)) indicating a power/weight ratio of > or =5.5 W/kg; (iii) the percentage of type I fibres in the vastus lateralis; (iv) maximal lactate steady-state, representing the highest exercise intensity at which blood lactate concentration remains stable; (v) W(peak) at LT2; and (vi) W(peak) during a maximal cycling test. Furthermore, the unique breathing pattern, characterised by a lack of tachypnoeic shift, found in professional cyclists may enhance the efficiency and metabolic cost of breathing. The training impulse is useful to characterise exercise intensity and load during training and competition. It serves to enable the cyclist or coach to evaluate the effects of training strategies and may well serve to predict the cyclist's performance. Findings indicate that peripheral adaptations in working muscles play a more important role for enhanced submaximal cycling capacity than central adaptations. Clearly, relatively brief but intense sprint training can enhance both glycolytic and oxidative enzyme activity, maximum short-term power output and V-O(2max). To that end, it is suggested to replace approximately 15% of normal training with one of the interval exercise protocols. Tapering, through reduction in duration of training sessions or the frequency of sessions per week while maintaining intensity, is extremely effective for improvement of cycling time-trial performance. Overuse and over-training disabilities common to the competitive cyclist, if untreated, can lead to delayed recovery.

  18. Life cycle assessment (LCA)

    DEFF Research Database (Denmark)

    Thrane, Mikkel; Schmidt, Jannick Andresen

    2004-01-01

    The chapter introduces Life Cycle Assessment (LCA) and its application according to the ISO 1404043 standards.......The chapter introduces Life Cycle Assessment (LCA) and its application according to the ISO 1404043 standards....

  19. Menstrual Cycle Problems

    Science.gov (United States)

    ... Read MoreDepression in Children and TeensRead MoreBMI Calculator Menstrual Cycle ProblemsFrom missed periods to painful periods, menstrual cycle problems are common, but usually not serious. Follow ...

  20. Physiological Demands of Simulated Off-Road Cycling Competition

    Science.gov (United States)

    Smekal, Gerhard; von Duvillard, Serge P.; Hörmandinger, Maximilian; Moll, Roland; Heller, Mario; Pokan, Rochus; Bacharach, David W.; LeMura, Linda M.; Arciero, Paul

    2015-01-01

    The purpose of the study was to measure the demands of off-road cycling via portable spirometry, leg-power output (PO), heart rate (HR) and blood lactate (BLa) concentration. Twenty-four male competitive cyclists (age: 29±7.2 yrs, height: 1.79 ± 0.05 m, body mass: 70.0 ± 4.9 kg, VO2peak: 64.9 ± 7.5 ml·kg-1·min-1) performed simulated mountain bike competitions (COMP) and laboratory tests (LabT). From LabT, we determined maximal workload and first and second ventilatory thresholds (VT1, VT2). A high-performance athlete (HPA) was used for comparison with three groups of subjects with different sport-specific performance levels. Load profiles of COMP were also investigated during uphill, flat and downhill cycling. During the COMP, athletes achieved a mean oxygen uptake (VO2COMP) of 57.0 ± 6.8 ml·kg-1·min-1 vs. 71.1 ml·kg-1·min-1 for the HPA. The POCOMP was 2.66±0.43 W·kg-1 and 3.52 W·kg-1 for the HPA. POCOMP, VO2COMP and HRCOMP were compared to corresponding variables at the VT2 of LabT. LabT variables correlated with racing time (RTCOMP) and POCOMP (p sports. Heart rate and blood lactate concentration measures are not sensitive enough to assess the energy requirements of COMP. Therefore, respiratory gas and power output measures are helpful to provide new information to physiological profile of cross- country cycling. An excellent cycling-specific capacity is a prerequisite for successful off-road cycling. Data determined from LabT might be utilized to describe semi-specific abilities of MB- athletes on a cycle ergometer, while data originating from COMP might be useful when designing a mountain bike specific training. PMID:26664277

  1. Middle cerebral artery blood velocity and plasma catecholamines during exercise

    DEFF Research Database (Denmark)

    Pott, F; Jensen, K; Hansen, H

    1996-01-01

    During dynamic exercise, mean blood velocity (Vmean) in the middle cerebral artery (MCA) demonstrates a graded increase to work rate and reflects regional cerebral blood flow. At a high work rate, however, vasoactive levels of plasma catecholamines could mediate vasoconstriction of the MCA...... and thereby elevate Vmean at a given volume flow. To evaluate transcranial Doppler-determined Vmean at high plasma catecholamine levels, seven elite cyclists performed a maximal performance test on a bicycle ergometer. Results were compared with those elicited during five incremental exercise bouts and during...... rhythmic handgrip when plasma catecholamines are low. During rhythmic handgrip the Vmean was elevated by 21 +/- 3% (mean +/- SE), which was not statistically different from that established during moderate cycling. However, at the highest submaximal and maximal work intensities on the bicycle ergometer...

  2. Cycling To Awareness.

    Science.gov (United States)

    Kozak, Stan

    1999-01-01

    Encourages environmental and outdoor educators to promote bicycling. In the community and the curriculum, cycling connects environmental issues, health and fitness, law and citizenship, appropriate technology, and the joy of being outdoors. Describes the Ontario Cycling Association's cycling strategy and its four components: school cycling…

  3. The Solar Cycle

    Directory of Open Access Journals (Sweden)

    David H. Hathaway

    2010-03-01

    Full Text Available The Solar Cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. We examine a number of other solar activity indicators including the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores that vary in association with the sunspots. We examine the characteristics of individual solar cycles including their maxima and minima, cycle periods and amplitudes, cycle shape, and the nature of active latitudes, hemispheres, and longitudes. We examine long-term variability including the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev–Ohl Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double peaked maxima. We conclude with an examination of prediction techniques for the solar cycle.

  4. MOOD DISTURBANCE DURING CYCLING PERFORMANCE AT EXTREME CONDITIONS

    Directory of Open Access Journals (Sweden)

    Matthew Wilson

    2005-03-01

    Full Text Available The purpose of the study was to investigate the effects of extreme environments on mood state changes in hypoxic conditions and cold conditions in comparison to baseline conditions. The research design involved participants completing a two-hour stationary cycle ergometer ride at a simulated altitude of 2,500 metres, O°C, and normal laboratory conditions at a pace equivalent of lactate threshold. Eight male elite cyclists (Age: M = 26.23 yrs., SD = 6.74 completed the hypoxia- normal cycling trials. Ten male highly trained cyclists (Age: M = 23.34 yrs., SD = 5.45 participated in the cold-normal trials. Mood was assessed before, after one hour, and after two hours using the 24-item Brunel Mood Scale. MANOVA results indicated no significant interaction effect for mood changes over time by environment condition (Wilks' Lambda = .73, p = .32, Eta2 = .05, a significant main effect for mood changes over time (Wilks' Lambda = .61. p < .001, Partial Eta2 = .15 and a significant main effect for differences in mood by condition (Wilks' Lambda = .72, p < .000, Partial Eta2 = .15. Results indicated that increased anger, depression and fatigue were associated with performing at altitude, particularly after two hours of exercise. Collectively, results lend support to the notion that altitude is associated with negative mood states, although it should be noted that environment conditions did not affect the change in mood states over time. We suggest that further research is needed to explore mechanisms that individuals use to regulate negative mood during strenuous exercise.

  5. Whole-body efficiency is negatively correlated with minimum torque per duty cycle in trained cyclists.

    Science.gov (United States)

    Edwards, Lindsay M; Jobson, Simon A; George, Simon R; Day, Stephen H; Nevill, Alan M

    2009-02-15

    The purpose of this study was to determine whether there is a causal relationship between pedalling "circularity" and cycling efficiency. Eleven trained cyclists were studied during submaximal cycling. Variables recorded included gross and delta efficiency and the ratio of minimum to peak torque during a duty cycle. Participants also completed a questionnaire about their training history. The most notable results were as follows: gross efficiency (r = -0.72, P ratio of minimum to peak torque, particularly at higher work rates. There was a highly significant inverse correlation between delta efficiency and average minimum torque at 200 W (r = -0.76, P efficiency and gross efficiency, although experience and the ratio of minimum to peak torque were not related. These results show that variations in pedalling technique may account for a large proportion of the variation in efficiency in trained cyclists. However, it is also possible that some underlying physiological factor influences both. Finally, it appears that experience positively influences efficiency, although the mechanism by which this occurs remains unclear.

  6. The role of sense of effort on self-selected cycling power output

    Directory of Open Access Journals (Sweden)

    Ryan James Christian

    2014-03-01

    Full Text Available Purpose: We explored the effects of the sense of effort and accompanying perceptions of peripheral discomfort on self-selected cycle power output under two different inspired O2 fractions.Methods: On separate days, eight trained males cycled for 5 minutes at a constant subjective effort (sense of effort of ‘3’ on a modified Borg CR10 scale, immediately followed by five 4-s progressive submaximal (sense of effort of 4, 5, 6, 7 and 8; 40 s between bouts and two 4-s maximal (sense of effort of 10; 3 min between bouts bouts under normoxia (NM: fraction of inspired O2 [FiO2] 0.21 and hypoxia (HY: [FiO2] 0.13. Physiological (Heart Rate, arterial oxygen saturation (SpO2 and quadriceps Root Mean Square (RMS electromyographical activity and perceptual responses (overall peripheral discomfort, difficulty breathing and limb discomfort were recorded.Results: Power output and normalized quadriceps RMS activity were not different between conditions during any exercise bout (p > 0.05 and remained unchanged across time during the constant-effort cycling. SpO2 was lower, while heart rate and ratings of perceived difficulty breathing were higher under HY, compared to NM, at all time points (p

  7. Warm-up effects from concomitant use of vibration and static stretching after cycling.

    Science.gov (United States)

    Yang, Wen-Wen; Liu, Chiang; Shiang, Tzyy-Yuang

    2017-04-01

    Static stretch is routinely used in traditional warm-up but impaired muscle performance. Combining vibration with static stretching as a feasible component may be an alternative to static stretching after submaximal aerobic exercise to improve jumping as well as flexibility. Therefore, the purpose of this study was to investigate and compare the effects of aerobic exercise, static stretching, and vibration with static stretching on flexibility and vertical jumping performance. A repeated measures experimental design was used in this study. Twelve participants randomly underwent 5 different warm-ups including cycling alone (C warm-up), static stretching alone (S warm-up), combining vibration with static stretching (VS warm-up), cycling followed by S (C+S warm-up), and cycling followed by VS (C+VS warm-up) on 5 separate days. Sit-and-reach, squat jump (SJ), and counter movement jump (CMJ) were measured for pre- and post- tests. The sit-and-reach scores after the S, VS, C+S and C+VS warm-ups were significantly enhanced (Pperformance, compared with the traditional warm-up (C+S warm-up).

  8. Effects of interactive video game cycling on overweight and obese adolescent health.

    Science.gov (United States)

    Adamo, Kristi B; Rutherford, Jane A; Goldfield, Gary S

    2010-12-01

    The purpose of this study was to examine the efficacy of interactive video game stationary cycling (GameBike) in comparison with stationary cycling to music on adherence, energy expenditure measures, submaximal aerobic fitness, body composition, and cardiovascular disease risk markers in overweight and obese adolescents, using a randomized controlled trial design. Thirty overweight (with at least 1 metabolic complication) or obese adolescents aged 12-17 years were stratified by gender and randomized to video game or music condition, with 4 participants (2 per group) failing to complete the twice weekly 60 min sessions of the 10-week trial. The music group had a higher rate of attendance compared with the video game group (92% vs. 86%, p Time spent in minutes per session at vigorous intensity (80%-100% of predicted peak heart rate) (24.9 ± 20 min vs. 13.7 ± 12.8 min, p playing video games at improving fitness, body composition, and cholesterol profiles in overweight and obese teens, and resulted in increased attendance, vigorous intensity of physical activity, and distance pedaled. Therefore, our data support the superiority of cycling to music and indicate investing in the more expensive GameBike may not be worth the cost.

  9. Cortical Oxyhemoglobin Elevation Persists After Moderate-Intensity Cycling Exercise: A Near-Infrared Spectroscopy Study.

    Science.gov (United States)

    Tsubaki, Atsuhiro; Takehara, Nana; Sato, Daisuke; Morishita, Shinichiro; Tokunaga, Yuta; Sugawara, Kazuhiro; Kojima, Sho; Tamaki, Hiroyuki; Yamazaki, Yudai; Onishi, Hideaki

    2017-01-01

    Near-infrared spectroscopy (NIRS) can measure cortical activity during gross motor tasks based on the cerebral hemodynamic response. Although some reports suggest that cycling exercise improves cortical oxygenation, its after-effects are unknown. We examined the after-effects of low- and moderate-intensity cycling exercise on cortical oxygenation. Ten healthy volunteers (mean age 21.3 ± 0.7 years; 4 women) underwent cycle ergometer exercise at 30% or 50% of VO2peak for 20 min, followed by an 8-min post-exercise rest (PER). O2Hb levels of the supplementary motor area (SMA) and sensorimotor cortex (SMC) were recorded using a near-infrared spectroscopy system. Skin blood flow (SBF) and mean arterial pressure (MAP) were continuously measured. The peak values of O2Hb between exercise and PER were compared. The O2Hb, SBF, and MAP increased in the exercise phase. SBF degraded over time, and MAP decreased immediately after exercise. The O2Hb decreased immediately and increased again in the PER. There were no significant differences between exercise and PER in the SMC in the 30% VO2peak experiment or in the SMA and SMC in the 50% VO2peak experiment. The O2Hb in the motor-related area was elevated during both exercise and PER especially in the 50% VO2peak experiment.

  10. The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint

    Directory of Open Access Journals (Sweden)

    Shaun M. Phillips, Scott Findlay, Mykolas Kavaliauskas, Marie Clare Grant

    2014-06-01

    Full Text Available The objective of the study was to investigate the influence of serial administration of a carbohydrate (CHO mouth rinse on performance, metabolic and perceptual responses during a cycle sprint. Twelve physically active males (mean (± SD age: 23.1 (3.0 years, height: 1.83 (0.07 m, body mass (BM: 86.3 (13.5 kg completed the following mouth rinse trials in a randomized, counterbalanced, double-blind fashion; 1. 8 x 5 second rinses with a 25 ml CHO (6% w/v maltodextrin solution, 2. 8 x 5 second rinses with a 25 ml placebo (PLA solution. Following mouth rinse administration, participants completed a 30 second sprint on a cycle ergometer against a 0.075 g·kg-1 BM resistance. Eight participants achieved a greater peak power output (PPO in the CHO trial, resulting in a significantly greater PPO compared with PLA (13.51 ± 2.19 vs. 13.20 ± 2.14 W·kg-1, p 0.05. No significant between-trials difference was reported for fatigue index, perceived exertion, arousal and nausea levels, or blood lactate and glucose concentrations. Serial administration of a CHO mouth rinse may significantly improve PPO during a cycle sprint. This improvement appears confined to the first 5 seconds of the sprint, and may come at a greater relative cost for the remainder of the sprint.

  11. "Graded Cycling Test with Talk Test" Is a Reliable Test to Monitor Cardiovascular Fitness in Patients with Minor Stroke

    DEFF Research Database (Denmark)

    Steen Krawcyk, Rikke; Vinther, Anders; Caesar Petersen, Nicolas

    2017-01-01

    BACKGROUND: Physical exercise is generally recommended as part of life style changes post stroke. Monitoring cardiovascular effects may help motivate patients for further exercise, and can be an instrument to assess intervention effects in clinical trials. In 1 of 4 stroke patients, the heart rate...... variability may challenge currently used cardiovascular monitoring. The Graded Cycling Test with Talk Test is a submaximal exercise test independent of heart rate variability, shown reliable for patients with cardiac disease. METHODS: Patients diagnosed with lacunar stroke according to TOAST (Trial of Org...... 10172 in Acute Stroke Treatment) criteria performed an incremental exercise test on a stationary bicycle with a 15 W (watt) increase in workload every minute. Toward the end of each incremental step, the patients recited a standardized text passage and subsequently were asked: "Are you still able...

  12. Effects of two different half-squat training programs on fatigue during repeated cycling sprints in soccer players.

    Science.gov (United States)

    Bogdanis, Gregory C; Papaspyrou, Aggeliki; Souglis, Athanasios G; Theos, Apostolos; Sotiropoulos, Aristomenis; Maridaki, Maria

    2011-07-01

    This study compared the effects of two different half-squat training programs on the repeated-sprint ability of soccer players during the preseason. Twenty male professional soccer players were divided into 2 groups: One group (S-group) performed 4 sets of 5 repetitions with 90% of their 1-repetition maximum (1RM), and the other group (H-group) performed 4 sets of 12 repetitions with 70% of 1RM, 3 times per week for 6 weeks, in addition to their common preseason training program. Repeated-sprint ability was assessed before and after training by 10 × 6-second cycle ergometer sprints separated by 24 seconds of passive recovery. Maximal half-squat strength increased significantly in both groups (p repeated sprint ability. Therefore, resistance training with high loads may be preferable when the aim is to improve maximal strength and fatigue during sprinting in professional soccer players.

  13. The Solar Cycle

    Directory of Open Access Journals (Sweden)

    David H. Hathaway

    2015-09-01

    Full Text Available The solar cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. A number of other solar activity indicators also vary in association with the sunspots including; the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores. Individual solar cycles are characterized by their maxima and minima, cycle periods and amplitudes, cycle shape, the equatorward drift of the active latitudes, hemispheric asymmetries, and active longitudes. Cycle-to-cycle variability includes the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev–Ohl (even-odd Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double-peaked maxima. We conclude with an examination of prediction techniques for the solar cycle and a closer look at cycles 23 and 24.

  14. [Influence of carbon fiber foot orthoses on plantar pressure distribution in cycling].

    Science.gov (United States)

    Baur, Heiner; Hoffmann, Jan; Reichmuth, Anne; Müller, Steffen; Mayer, Frank

    2012-03-01

    Several equipment interventions like optimizing seat position or optimizing shoe/insole/pedal interface are suggested to reduce overuse injury in cycling. Data analyzing clinical or biomechanical effects of those interventions is sparse. Foot orthoses out of carbon fiber are one possibility to alter the interface between foot and pedal. The aim of this study was therefore to analyze plantar pressure distribution in carbon fiber foot orthoses in comparison to standard insoles of commercially available cycling shoes. 11 painfree triathletes (Age: 29±9, 1.77±0.04 m, 68±5 kg) were tested on a cycle ergometer at 60 and 90 rotations per minute (rpm) at workloads of 200 and 300 Watts. Subjects wore in randomized order a cycling shoe with its standard insole (control condition CO) or the shoe with carbon fiber foot orthoses (Condition CA). Mean peak pressure out of 30 movement cycles were extracted for the total foot and specific foot regions (rear, mid, fore foot (medial, central, lateral) and toe region). Three-factor ANOVAs (factor foot orthoses, rpm, workload) for repeated measures (α = 0.05) were used to analyze the main question of a foot orthoses effect on peak in-shoe plantar pressure. Peak pressures in the total foot were in a range of 70-75 kPa for 200 Watts (W) (300 W: 85-110 kPa). The carbon fiber foot orthoses reduced peak pressures by -4,1% compared to the standard insole (p = 0,10). In the foot regions rear (-16,6 %, p Carbon fiber can serve as a suitable material for foot orthoses manufacturing in cycling. Plantar pressures do not increase due to the stiffness of the carbon. Individual customization may have the potential to reduce peak pressure in certain foot areas. Georg Thieme Verlag KG Stuttgart · New York.

  15. Stimulation of shank muscles during functional electrical stimulation cycling increases ankle excursion in individuals with spinal cord injury.

    Science.gov (United States)

    Fornusek, Ché; Davis, Glen M; Baek, Ilhun

    2012-11-01

    To investigate the effect of shank muscle stimulation on ankle joint excursion during passive and functional electrical stimulation (FES) leg cycling. Within-subject comparisons. Laboratory setting. Well-trained FES cyclists (N=7) with chronic spinal cord injuries. Two experimental sessions were performed on an isokinetic FES cycle ergometer with a pedal boot that allowed the ankle to plantarflex and dorsiflex during cycling. During the first session, the optimal stimulation timings to induce plantarflexion and dorsiflexion were investigated by systematically altering the stimulation angles of the shank muscles (tibialis anterior [TA] and triceps surae [TS]). During the second session, TA and TS stimulation was included with standard FES cycling (quadriceps, hamstrings, and gluteals) for 6 subjects. Ankle, knee, and hip movements were analyzed using 2-dimensional video. The ankle excursions during passive cycling were 19°±6°. TA and TS stimulation increased ankle joint excursion up to 33°±10° and 27°±7°, respectively. Compared with passive cycling, ankle joint excursion was not significantly increased during standard FES cycling (24°±7°). TA and TS stimulation significantly increased the ankle excursion when applied during standard FES cycling (41°±4°). Freeing the ankle joint to rotate during FES cycling was found to be safe. The combination of shank muscle stimulation and repetitive ankle joint movement may be beneficial for improving ankle flexibility and leg conditioning. Further research is required to test and design ankle supports that might maximize the benefits of shank muscle activation. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  16. Driving and engine cycles

    CERN Document Server

    Giakoumis, Evangelos G

    2017-01-01

    This book presents in detail the most important driving and engine cycles used for the certification and testing of new vehicles and engines around the world. It covers chassis and engine-dynamometer cycles for passenger cars, light-duty vans, heavy-duty engines, non-road engines and motorcycles, offering detailed historical information and critical review. The book also provides detailed examples from SI and diesel engines and vehicles operating during various cycles, with a focus on how the engine behaves during transients and how this is reflected in emitted pollutants, CO2 and after-treatment systems operation. It describes the measurement methods for the testing of new vehicles and essential information on the procedure for creating a driving cycle. Lastly, it presents detailed technical specifications on the most important chassis-dynamometer cycles around the world, together with a direct comparison of those cycles.

  17. Can endurance training improve physical capacity and quality of life in young Fontan patients?

    Science.gov (United States)

    Hedlund, Eva R; Lundell, Bo; Söderström, Liselott; Sjöberg, Gunnar

    2017-12-14

    Children after Fontan palliation have reduced exercise capacity and quality of life. Our aim was to study whether endurance training could improve physical capacity and quality of life in Fontan patients. Fontan patients (n=30) and healthy age- and gender-matched control subjects (n=25) performed a 6-minute walk test at submaximal capacity and a maximal cycle ergometer test. Quality of life was assessed with Pediatric Quality of Life Inventory Version 4.0 questionnaires for children and parents. All tests were repeated after a 12-week endurance training programme and after 1 year. Patients had decreased submaximal and maximal exercise capacity (maximal oxygen uptake 35.0±5.1 ml/minute per·kg versus 43.7±8.4 ml/minute·per·kg, ptraining, patients improved their submaximal exercise capacity in a 6-minute walk test (from 590.7±65.5 m to 611.8±70.9 m, ptraining. At follow-up, improvement of maximal exercise capacity was sustained. We believe that an individualised endurance training programme for Fontan patients improves submaximal exercise capacity and quality of life in Fontan patients and the effect on quality of life appears to be long-lasting.

  18. Vuilleumier Cycle Cryogenic Refrigeration

    Science.gov (United States)

    1976-04-01

    changing pressure to produce a cooling effect is similar to that of the cold section of the Stirling cycle refrigerator , since the method by which the...AFFDL-TR-76-17 VUILLEUMIER CYCLE CRYOGENIC REFRIGERATION ENVIRONMENTAL CONTROL BRANCH 4 VEHICLE EQUIPMENT DIVISION APRIL 1976 TECHNICAL REPORT AFFDL...WORDS (Continue on reverse side if necessary and identify by block number) Cryogenic Refrigerator Vuilleumier Cycle 20. ABSTRACT (Continue on reverse

  19. [Cycling in Zagreb].

    Science.gov (United States)

    Matos, Stipan; Krapac, Ladislav; Krapac, Josip

    2007-01-01

    Cycling in Zagreb, as means of urban transport inside and outside the city, has a bright past, hazy presence but a promising future. Every day, aggressive citizens who lack urban traffic culture mistreat many cyclists but also many pedestrians. Sedentary way of living, unhealthy eating habits and inadequate recreation would surely be reduced if Zagreb had a network of cycling tracks (190 cm) or lanes (80 cm). Main city roads were constructed at the beginning of the 20th century. Today, the lack of cycling tracks is particularly evident in terms of missing connections between northern and southern parts of the city. Transportation of bikes in public vehicles, parking of bikes as well as cycling along the foot of the mountains Medvednica and Zumberacko gorje is not adequately organized. Better organization is necessary not only because of the present young generation but also because of the young who will shortly become citizens of the EU, where cycling is enormously popular. Cycling tourism is not known in Zagreb, partly due to inadequate roads. The surroundings of Zagreb are more suitable for cycling tourism and attractive brochures and tourist guides offer information to tourists on bikes. Professional, acrobatic and sports cycling do not have a tradition in Zagreb and in Croatia. The same holds true for recreational cycling and indoor exercise cycling. The authors discuss the impact of popularization of cycling using print and electronic media. The role of district and local self-government in the construction and improvement of traffic roads in Zagreb is very important. It is also significant for the implementation of legal regulations that must be obeyed by all traffic participants in order to protect cyclists, the most vulnerable group of traffic participants besides passengers. Multidisciplinary action of all benevolent experts would surely increase safety and pleasure of cycling in the city and its surroundings. This would also help reduce daily stress and

  20. The nitrogen cycle

    National Research Council Canada - National Science Library

    Stein, Lisa Y; Klotz, Martin G

    2016-01-01

    .... Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions...

  1. Edgeworth cycles revisited

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Joseph [MIT Sloan School of Management, 50 Memorial Drive, E52-447, Cambridge MA 02142 (United States); Muehlegger, Erich [John F. Kennedy School of Government, Harvard University, Mailbox 25, 79 JFK Street, Cambridge, MA 02138 (United States); Samphantharak, Krislert [Graduate School of International Relations and Pacific Studies, University of California at San Diego, 9500 Gilman Drive 1519, La Jolla, CA 92093 (United States)

    2010-05-15

    Some gasoline markets exhibit remarkable price cycles, where price spikes are followed by a series of small price declines: a pattern consistent with a model of Edgeworth cycles described by Maskin and Tirole. We extend the model and empirically test its predictions with a new dataset of daily station-level prices in 115 US cities. Consistent with the theory, and often in contrast with previous empirical work, we find the least and most concentrated markets are much less likely to exhibit cycling behavior both within and across cities; areas with more independent convenience-store gas stations are also more likely to cycle. (author)

  2. Universal cycle periods

    NARCIS (Netherlands)

    Groot, de E.A. (Bert); Franses, P.H.P.H.

    2009-01-01

    We present a meta-analysis of cycles in historical economic data. The literature on stochastic and deterministic cycles in variables such as the consumer price index, employment, interest rates, commodity prices, and GDP is huge and scattered, but our meta-analysis reveals various communalities. Our

  3. Stability through cycles

    NARCIS (Netherlands)

    Groot, de E.A. (Bert); Franses, P.H.P.H.

    2006-01-01

    Economic variables like GDP growth, employment, interest rates and consumption show signs of cyclical behavior. Many variables display multiple cycles, with lengths ranging in between 5 to even up to 100 years. We argue that multiple cycles can be associated with long-run stability of the economic

  4. Life Cycle Environmental Management

    DEFF Research Database (Denmark)

    Pedersen, Claus Stig; Jørgensen, Jørgen; Pedersen, Morten Als

    1996-01-01

    processes. The discipline of life cycle environmental management (LCEM) focuses on the incorporation of environmental criteria from the life cycles of products and other company activities into the company management processes. This paper introduces the concept of LCEM as an important element...

  5. Teaching the Krebs Cycle.

    Science.gov (United States)

    Akeroyd, F. Michael

    1983-01-01

    Outlines a simple but rigorous treatment of the Krebs Cycle suitable for A-level Biology students. The importance of the addition of water molecules in various stages of the cycle is stressed as well as the removal of hydrogen atoms by the oxidizing enzymes. (JN)

  6. Rock Cycle Roulette.

    Science.gov (United States)

    Schmidt, Stan M.; Palmer, Courtney

    2000-01-01

    Introduces an activity on the rock cycle. Sets 11 stages representing the transitions of an earth material in the rock cycle. Builds six-sided die for each station, and students move to the stations depending on the rolling side of the die. Evaluates students by discussing several questions in the classroom. Provides instructional information for…

  7. Life Cycle Impact Assessment

    DEFF Research Database (Denmark)

    Rosenbaum, Ralph K.; Hauschild, Michael Zwicky; Boulay, Anne-Marie

    2017-01-01

    This chapter is dedicated to the third phase of an LCA study, the Life Cycle Impact Assessment (LCIA) where the life cycle inventory’s information on elementary flows is translated into environmental impact scores. In contrast to the three other LCA phases, LCIA is in practice largely automated...

  8. Life cycle management (LCM)

    DEFF Research Database (Denmark)

    Remmen, Arne; Thrane, Mikkel

    2004-01-01

    The chapter gives an introduction to Life Cycle Management (LCM) and shows how LCM can be practiced in different contexts and at different ambition levels.......The chapter gives an introduction to Life Cycle Management (LCM) and shows how LCM can be practiced in different contexts and at different ambition levels....

  9. Seeing the Carbon Cycle

    Science.gov (United States)

    Drouin, Pamela; Welty, David J.; Repeta, Daniel; Engle-Belknap, Cheryl A.; Cramer, Catherine; Frashure, Kim; Chen, Robert

    2006-01-01

    In this article, the authors present a classroom experiment that was developed to introduce middle school learners to the carbon cycle. The experiment deals with transfer of CO[subscript 2] between liquid reservoirs and the effect CO[subscript 2] has on algae growth. It allows students to observe the influence of the carbon cycle on algae growth,…

  10. The carbon cycle revisited

    Science.gov (United States)

    Bolin, Bert; Fung, Inez

    1992-01-01

    Discussions during the Global Change Institute indicated a need to present, in some detail and as accurately as possible, our present knowledge about the carbon cycle, the uncertainties in this knowledge, and the reasons for these uncertainties. We discuss basic issues of internal consistency within the carbon cycle, and end by summarizing the key unknowns.

  11. Power Plant Cycling Costs

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N.; Besuner, P.; Lefton, S.; Agan, D.; Hilleman, D.

    2012-07-01

    This report provides a detailed review of the most up to date data available on power plant cycling costs. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities.

  12. The Impact of the Progressive Efficiency Test on a Rowing Ergometer on White Blood Cells Distribution and Clinical Chemistry Changes in Paralympic Rowers During the Preparatory Stage Before the Paralympic Games in Rio, 2016 – A Case Report

    Science.gov (United States)

    Nowak, Robert; Buryta, Rafał; Krupecki, Krzysztof; Zając, Tomasz; Zawartka, Marek; Proia, Patrizia

    2017-01-01

    Abstract There is a large gap in knowledge regarding research on post-exercise blood changes in disabled athletes. There are relatively few data on adaptive mechanisms to exercise in disabled athletes, including disabled rowers. Two rowers from a Polish adaptive rowing settle TAMix2x that qualified for the Paralympic Games in Rio, 2016 took part in this study. They performed a progressive test on a rowing ergometer until exhaustion. The cardiorespiratory fitness measures, complete blood count, white blood cells’ distribution and 30 clinical chemistry variables describing laboratory diagnostic profiles and general health were determined. The extreme effort induced changes in all studied metabolites (glucose, creatinine, urea, uric acid, total and direct bilirubin), albumin, total protein levels in both participants. Furthermore, a post-exercise increase in aspartate transaminase activity, yet a 2-fold decrease during the recovery time in both rowers were found. White blood cell count increased 2-fold after the test. The percentages of natural killer cells were higher and total T lymphocytes were lower after the exercise protocol. There were higher percentages of suppressor/cytotoxic and lower percentages of helper/inducer T lymphocyte subsets in both studied rowers. No changes in B lymphocytes distribution were observed. Lack of inflammatory symptoms during the experiment suggests a high level of rowers’ biological adaptation to the physical effort. The different changes in physiological, biochemical and immunological variables are related to the adaptive mechanism to physical exercise allowing for improvement of performance. PMID:29340006

  13. The Impact of the Progressive Efficiency Test on a Rowing Ergometer on White Blood Cells Distribution and Clinical Chemistry Changes in Paralympic Rowers During the Preparatory Stage Before the Paralympic Games in Rio, 2016 - A Case Report.

    Science.gov (United States)

    Nowak, Robert; Buryta, Rafał; Krupecki, Krzysztof; Zając, Tomasz; Zawartka, Marek; Proia, Patrizia; Kostrzewa-Nowak, Dorota

    2017-12-01

    There is a large gap in knowledge regarding research on post-exercise blood changes in disabled athletes. There are relatively few data on adaptive mechanisms to exercise in disabled athletes, including disabled rowers. Two rowers from a Polish adaptive rowing settle TAMix2x that qualified for the Paralympic Games in Rio, 2016 took part in this study. They performed a progressive test on a rowing ergometer until exhaustion. The cardiorespiratory fitness measures, complete blood count, white blood cells' distribution and 30 clinical chemistry variables describing laboratory diagnostic profiles and general health were determined. The extreme effort induced changes in all studied metabolites (glucose, creatinine, urea, uric acid, total and direct bilirubin), albumin, total protein levels in both participants. Furthermore, a post-exercise increase in aspartate transaminase activity, yet a 2-fold decrease during the recovery time in both rowers were found. White blood cell count increased 2-fold after the test. The percentages of natural killer cells were higher and total T lymphocytes were lower after the exercise protocol. There were higher percentages of suppressor/cytotoxic and lower percentages of helper/inducer T lymphocyte subsets in both studied rowers. No changes in B lymphocytes distribution were observed. Lack of inflammatory symptoms during the experiment suggests a high level of rowers' biological adaptation to the physical effort. The different changes in physiological, biochemical and immunological variables are related to the adaptive mechanism to physical exercise allowing for improvement of performance.

  14. The Impact of the Progressive Efficiency Test on a Rowing Ergometer on White Blood Cells Distribution and Clinical Chemistry Changes in Paralympic Rowers During the Preparatory Stage Before the Paralympic Games in Rio, 2016 – A Case Report

    Directory of Open Access Journals (Sweden)

    Nowak Robert

    2017-12-01

    Full Text Available There is a large gap in knowledge regarding research on post-exercise blood changes in disabled athletes. There are relatively few data on adaptive mechanisms to exercise in disabled athletes, including disabled rowers. Two rowers from a Polish adaptive rowing settle TAMix2x that qualified for the Paralympic Games in Rio, 2016 took part in this study. They performed a progressive test on a rowing ergometer until exhaustion. The cardiorespiratory fitness measures, complete blood count, white blood cells’ distribution and 30 clinical chemistry variables describing laboratory diagnostic profiles and general health were determined. The extreme effort induced changes in all studied metabolites (glucose, creatinine, urea, uric acid, total and direct bilirubin, albumin, total protein levels in both participants. Furthermore, a post-exercise increase in aspartate transaminase activity, yet a 2-fold decrease during the recovery time in both rowers were found. White blood cell count increased 2-fold after the test. The percentages of natural killer cells were higher and total T lymphocytes were lower after the exercise protocol. There were higher percentages of suppressor/cytotoxic and lower percentages of helper/inducer T lymphocyte subsets in both studied rowers. No changes in B lymphocytes distribution were observed. Lack of inflammatory symptoms during the experiment suggests a high level of rowers’ biological adaptation to the physical effort. The different changes in physiological, biochemical and immunological variables are related to the adaptive mechanism to physical exercise allowing for improvement of performance.

  15. Cycling time to failure is better maintained by cold than contrast or thermoneutral lower-body water immersion in normothermia.

    Science.gov (United States)

    Crampton, David; Donne, Bernard; Warmington, Stuart A; Egaña, Mikel

    2013-12-01

    To examine the effects of four commonly used recovery treatments applied between two bouts of intense endurance cycling on the performance of the second bout in normothermia (~21 °C). Nine trained men completed two submaximal exhaustive cycling bouts (Ex1 and Ex2: 5 min at ~50 % [Formula: see text] peak, followed by 5 min at ~60 % [Formula: see text] peak and then ~80 % [Formula: see text] peak to failure) separated by 30 min of (a) cold water immersion at 15 °C (C15), (b) contrast water therapy alternating 2.5 min at 8 °C and 2.5 min at 40 °C (CT), (c) thermoneutral water immersion at 34 °C (T34) and (d) cycling at ~40 % [Formula: see text] peak (AR). Exercise performance, cardiovascular and metabolic responses during Ex1 were similar among all trials. However, time to failure (~80 % [Formula: see text] peak bout) during Ex2 was significantly (P cycling performance than CT, T34 and AR; and CT was also more beneficial than T34 and AR. These effects were not mediated by the effect of water immersion per se, but by the continuous (C15) or intermittent (CT) temperature stimulus (cold) applied throughout the recovery.

  16. Effects of caffeine on neuromuscular fatigue and performance during high-intensity cycling exercise in moderate hypoxia.

    Science.gov (United States)

    Smirmaul, Bruno P C; de Moraes, Antonio Carlos; Angius, Luca; Marcora, Samuele M

    2017-01-01

    To investigate the effects of caffeine on performance, neuromuscular fatigue and perception of effort during high-intensity cycling exercise in moderate hypoxia. Seven adult male participants firstly underwent an incremental exercise test on a cycle ergometer in conditions of acute normobaric hypoxia (fraction inspired oxygen = 0.15) to establish peak power output (PPO). In the following two visits, they performed a time to exhaustion test (78 ± 3% PPO) in the same hypoxic conditions after caffeine ingestion (4 mg kg -1 ) and one after placebo ingestion in a double-blind, randomized, counterbalanced cross-over design. Caffeine significantly improved time to exhaustion by 12%. A significant decrease in subjective fatigue was found after caffeine consumption. Perception of effort and surface electromyographic signal amplitude of the vastus lateralis were lower and heart rate was higher in the caffeine condition when compared to placebo. However, caffeine did not reduce the peripheral and central fatigue induced by high-intensity cycling exercise in moderate hypoxia. The caffeine-induced improvement in time to exhaustion during high-intensity cycling exercise in moderate hypoxia seems to be mediated by a reduction in perception of effort, which occurs despite no reduction in neuromuscular fatigue.

  17. Influence of the menstrual cycle and oral contraceptives on thermoregulatory responses to exercise in young women.

    Science.gov (United States)

    Grucza, R; Pekkarinen, H; Titov, E K; Kononoff, A; Hänninen, O

    1993-01-01

    Thermoregulatory responses to exercise in relation to the phase of the menstrual cycle were studied in ten women taking oral contraceptives (P) and in ten women not taking oral contraceptives (NP). Each subject was tested for maximal aerobic capacity (VO2max) and for 50% VO2max exercise in the follicular (F) and luteal (L) phases of the menstrual cycle. Since the oral contraceptives would have prevented ovulation a quasi-follicular phase (q-F) and a quasi-luteal phase (q-L) of the menstrual cycle were assumed for P subjects. Exercise was performed on a cycle ergometer at an ambient temperature of 24 degrees C and relative air humidity of 50%. Rectal (Tre), mean skin (Tsk), mean body (Tb) temperatures and heart rate (fc) were measured. Sweat rate was estimated by the continuous measurement of relative humidity of air in a ventilated capsule placed on the chest, converted to absolute pressure (PH2Ochest). Gain for sweating was calculated as a ratio of increase in PH2Ochest to the appropriate increase in Tre for the whole period of sweating (G) and for unsteady-state (Gu) separately. The VO2max did not differ either between the groups of subjects or between the phases of the menstrual cycle. In P, rectal temperature threshold for sweating (Tre,td) was 37.85 degrees C in q-L and 37.60 degrees C in q-F (P menstrual phase-related differences were observed either in the dynamics of sweating or in G.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Response to functional electrical stimulation cycling in women with spinal cord injuries using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography: a case series.

    Science.gov (United States)

    Ashe, Maureen C; Eng, Janice J; Krassioukov, Andrei V; Warburton, Darren E R; Hung, Chihya; Tawashy, Amira

    2010-01-01

    Loss of bone mass is common after spinal cord injury (SCI). One rehabilitation modality that has shown some promise for maintaining bone health is the functional electrical stimulation (FES) cycle ergometer. Although there has been some research investigating bone health and FES cycle ergometry, few have provided a detailed description of the changes that can occur in bone mass and soft-tissue mass. To use 2 types of bone imaging, peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA), to provide a detailed description of bone and soft-tissue response to FES cycle ergometry training in women with SCI. Case series; a 6-month program of FES cycle ergometry for women with chronic motor complete (n = 2) and incomplete (n = 1) SCI. Outpatient rehabilitation center in Canada. Three women participated in a thrice weekly 6-month exercise program of FES cycle ergometry. We used DXA (lower extremity) and pQCT at the midshaft (50%) and distal (5%) sites of the tibia to assess bone density and soft-tissue mass before and after the exercise program. There was an increase or maintenance in bone mineral density by DXA and pQCT in the lower extremity for all 3 participants. Muscle mass by DXA increased in the lower extremity in 2 participants. In this case series, we note a positive response in bone mass and soft-tissue mass in the lower extremity after a 6-month FES cycle ergometry program.

  19. Carbohydrate mouth rinse improves cycling performance carried out until the volitional exhaustion.

    Science.gov (United States)

    Bavaresco Gambassi, Bruno; Gomes de Santana Barros Leal, Ylana; Pinheiro Dos Anjos, Edson R; Antonelli, Bruna A; Gomes Gonçalves E Silva, Daniela C; Pires de Mélo Montenegro, Iracema H; di Cássia de Oliveira Angelo, Rita; Correia Moura, Isis S; Schwingel, Paulo A

    2017-11-17

    Carbohydrates (CHO) are among the most investigated nutritional ergogenic aids, and may be consumed in different forms, e.g., mouth rinse with carbohydrate solution (MRCS). In this sense, the aim of this study was to evaluate the impact of MRCS on the performance of physically active individuals undergoing a physical exercise session carried out until the volitional exhaustion. This is a counter-balanced randomized study, with a double-blind design. The sample consisted of twenty-one physically active healthy men with a mean (±SD) of age of 22.4 (±2.7) years old, 76.7 (±6.0) cm of height,12.1% (±3.7) of body fat mass, and 23.9 (±2.4) kg/m2 of body mass index. After familiarizing the participants with the protocol (cycle ergometer, with oral mouth rinse procedure) and assessing the maximal lactate steady state the cycling exercise was performed until the volitional exhaustion in the following conditions: without mouth rinse (CONTROL), PLACEBO and MRCS. Time to reach exhaustion was statistically different (pexhaustion until the volitional exhaustion. Thus, the use of methodology proposed by the present study may help coaches and practitioners improve the performance of physically active young adults.

  20. Evaluation of Electromyographic Frequency Domain Changes during a Three-Minute Maximal Effort Cycling Test

    Directory of Open Access Journals (Sweden)

    Ran Wang, David H. Fukuda, Jeffrey R. Stout, Edward H. Robinson, Amelia A. Miramonti, Maren S. Fragala, Jay R. Hoffman

    2015-06-01

    Full Text Available To evaluate the time course of EMG frequency changes during a three-minute maximal effort cycling test (3MT session and to examine which parameter between mean (MNF and median (MDF frequency is more suitable for evaluation of changes in neuromuscular function throughout a 3MT. Eighteen recreationally-active men volunteered to participate in this study. Maximum voluntary contraction (MVC was measured using a dynamometer to determine maximal EMG frequency of the vastus lateralis (VL of the kicking leg during isometric knee extension. A maximal oxygen consumption test (VO2peak on a cycle ergometer was performed to establish the appropriate load profile for the 3MT which was completed after a period of at least 48 hours. MNF, MDF and power output (PO values were measured at 10-second epochs throughout the duration of the 3MT. Repeated measures analysis of variance was used to compare the changes in EMG frequency, relative to maximal values from the MVC, and change in PO during the testing procedure. MNF, Root Mean Square (RMS, and PO significantly decreased during the 3MT, while MDF did not change significantly. Statistically, EMG frequency and PO decreased at first and remained constant in response to the 3MT, which may be reflective of differing patterns of muscle fiber type fatigue throughout the testing session. Due to decreased variability, changes in neuromuscular function during this protocol may be better evaluated using MNF than MDF.

  1. Life Cycle Management

    DEFF Research Database (Denmark)

    Bey, Niki

    2017-01-01

    This chapter gives an overview of Life Cycle Management (LCM)—a discipline that deals with the managerial tasks related to practicing sustainable development in an organisation . Just as Life Cycle Assessment, LCM advocates the life cycle perspective , and it applies this perspective in decision......-making processes. The chapter shows that LCA can play a key role in LCM since LCA provides quantitative performance measurements. It also explains, which stakeholders need to be considered, how LCA and LCM relate, how LCA can be used to develop Key Performance Indicators, and addresses how LCM can be integrated...

  2. Political Budget Cycles

    DEFF Research Database (Denmark)

    Aaskoven, Lasse; Lassen, David Dreyer

    2017-01-01

    The political budget cycle—how elections affect government fiscal policy—is one of the most studied subjects in political economy and political science. The key theoretical question is whether incumbent governments can time or structure public finances in ways that improve their chances...... on political budget cycles have recently focused on conditions under which such cycles are likely to obtain. Much recent research focuses on subnational settings, allowing comparisons of governments in similar institutional environments, and a consensus on the presences of cycles in public finances......—and in the reporting of public finances—is beginning to emerge....

  3. Effects of combined high intensity arm and leg training on performance and cardio-respiratory measures.

    Science.gov (United States)

    Zinner, Christoph; Sperlich, Billy; Born, Dennis-Peter; Michels, Guido

    2017-01-01

    The purpose of this study was to investigate the effects of combined arm and leg high-intensity low-volume interval training (HIITarm+leg) on maximal oxygen uptake, myocardial measures (i.e. stroke volume, cardiac output, ejection fraction), Tissue Oxygenation Index (TOI) of the vastus lateralis and triceps brachii, as well as power output in comparison to leg HIIT (HIITleg) only. The 20 healthy, male and female volunteers completed six sessions of either HIITleg on a cycle ergometer or HIITarm+leg on an arm and leg cycle ergometer. During pre- and post-testing, the volunteers completed a submaximal and incremental test to exhaustion on a cycle ergometer. Magnitude based interference revealed likely to very likely beneficial effects for HIITarm+leg compared to HIITleg in maximal oxygen uptake, cardiac measures as well peak power output. The TOI following HIITarm+leg demonstrated likely to very likely increased oxygenation in the triceps brachii or the vastus lateralis when compared to HIITleg. The results suggest that six sessions of HIITarm+leg may likely to very likely improve maximal oxygen uptake, some inotropy-related cardiac measures with improved tissue oxygenation of the triceps brachii and vastus lateralis muscles resulting in greater leg peak power output.

  4. EFFECT OF THE ROTOR CRANK SYSTEM ON CYCLING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Simon A. Jobson

    2009-09-01

    Full Text Available The aim of this study was to evaluate the impact of a novel crank system on laboratory time-trial cycling performance. The Rotor system makes each pedal independent from the other so that the cranks are no longer fixed at 180°. Twelve male competitive but non-elite cyclists (mean ± s: 35 ± 7 yr, Wmax = 363 ± 38 W, VO2peak = 4.5 ± 0.3 L·min-1 completed 6-weeks of their normal training using either a conventional (CON or the novel Rotor (ROT pedal system. All participants then completed two 40.23-km time-trials on an air-braked ergometer, one using CON and one using ROT. Mean performance speeds were not different between trials (CON = 41.7 km·h-1 vs. ROT = 41.6 km·h-1, P > 0.05. Indeed, the pedal system used during the time-trials had no impact on any of the measured variables (power output, cadence, heart rate, VO2, RER, gross efficiency. Furthermore, the ANOVA identified no significant interaction effect between main effects (Time-trial crank system*Training crank system, P > 0.05. To the authors' knowledge, this is the first study to examine the effects of the Rotor system on endurance performance rather than endurance capacity. These results suggest that the Rotor system has no measurable impact on time-trial performance. However, further studies should examine the importance of the Rotor 'regulation point' and the suggestion that the Rotor system has acute ergogenic effects if used infrequently

  5. Product Life Cycle Planning

    National Research Council Canada - National Science Library

    Walaszek, Jeffrey

    2003-01-01

    .... This phase of work was undertaken to: (1) provide guidelines, technical support, and planning approaches for researchers that result in realistic life cycle plans for products emerging from the RSM...

  6. The Rock Cycle

    Science.gov (United States)

    Singh, Raman J.; Bushee, Jonathan

    1977-01-01

    Presents a rock cycle diagram suitable for use at the secondary or introductory college levels which separates rocks formed on and below the surface, includes organic materials, and separates products from processes. (SL)

  7. Cycles in graphs

    CERN Document Server

    Alspach, BR

    1985-01-01

    This volume deals with a variety of problems involving cycles in graphs and circuits in digraphs. Leading researchers in this area present here 3 survey papers and 42 papers containing new results. There is also a collection of unsolved problems.

  8. Traffic Signal Cycle Lengths

    Data.gov (United States)

    Town of Chapel Hill, North Carolina — Traffic signal location list for the town of Chapel Hill. This data set includes light cycle information as well as as intersection information.The Town of Chapel...

  9. Life Cycle Costing.

    Science.gov (United States)

    McCraley, Thomas L.

    1985-01-01

    Life cycle costing establishes a realistic comparison of the cost of owning and operating products. The formula of initial cost plus maintenance plus operation divided by useful life identifies the best price over the lifetime of the product purchased. (MLF)

  10. Solar Cycle Prediction

    Directory of Open Access Journals (Sweden)

    Kristóf Petrovay

    2010-12-01

    Full Text Available A review of solar cycle prediction methods and their performance is given, including forecasts for cycle 24. The review focuses on those aspects of the solar cycle prediction problem that have a bearing on dynamo theory. The scope of the review is further restricted to the issue of predicting the amplitude (and optionally the epoch of an upcoming solar maximum no later than right after the start of the given cycle. Prediction methods form three main groups. Precursor methods rely on the value of some measure of solar activity or magnetism at a specified time to predict the amplitude of the following solar maximum. Their implicit assumption is that each numbered solar cycle is a consistent unit in itself, while solar activity seems to consist of a series of much less tightly intercorrelated individual cycles. Extrapolation methods, in contrast, are based on the premise that the physical process giving rise to the sunspot number record is statistically homogeneous, i.e., the mathematical regularities underlying its variations are the same at any point of time and, therefore, it lends itself to analysis and forecasting by time series methods. Finally, instead of an analysis of observational data alone, model based predictions use physically (more or less consistent dynamo models in their attempts to predict solar activity. In their overall performance during the course of the last few solar cycles, precursor methods have clearly been superior to extrapolation methods. Nevertheless, most precursor methods overpredicted cycle 23, while some extrapolation methods may still be worth further study. Model based forecasts have not yet had a chance to prove their skills. One method that has yielded predictions consistently in the right range during the past few solar cycles is that of K. Schatten et al., whose approach is mainly based on the polar field precursor. The incipient cycle 24 will probably mark the end of the Modern Maximum, with the Sun

  11. Menstrual Cycle: Basic Biology

    OpenAIRE

    Hawkins, Shannon M.; Matzuk, Martin M.

    2008-01-01

    The basic biology of the menstrual cycle is a complex, coordinated sequence of events involving the hypothalamus, anterior pituitary, ovary, and endometrium. The menstrual cycle with all its complexities can be easily perturbed by environmental factors such as stress, extreme exercise, eating disorders, and obesity. Furthermore, genetic influences such as fragile X premutations (Chapter X), X chromosome abnormalities (Chapter X), and galactose-1-phosphate uridyltransferase (GALT) point mutati...

  12. Quantifying the Adaptive Cycle.

    Directory of Open Access Journals (Sweden)

    David G Angeler

    Full Text Available The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994-2011 data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  13. Quantifying the adaptive cycle

    Science.gov (United States)

    Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.

  14. Cycling efficiency and energy cost of walking in young and older adults.

    Science.gov (United States)

    Gaesser, Glenn A; Tucker, Wesley J; Sawyer, Brandon J; Bhammar, Dharini M; Angadi, Siddhartha S

    2018-02-01

    To determine whether age affects cycling efficiency and the energy cost of walking (Cw), 190 healthy adults, ages 18-81 yr, cycled on an ergometer at 50 W and walked on a treadmill at 1.34 m/s. Ventilation and gas exchange at rest and during exercise were used to calculate net Cw and net efficiency of cycling. Compared with the 18-40 yr age group (2.17 ± 0.33 J·kg -1 ·m -1 ), net Cw was not different in the 60-64 yr (2.20 ± 0.40 J·kg -1 ·m -1 ) and 65-69 yr (2.20 ± 0.28 J·kg -1 ·m -1 ) age groups, but was significantly ( P 60 yr, net Cw was significantly correlated with age ( R 2  = 0.123; P = 0.002). Cycling net efficiency was not different between 18-40 yr (23.5 ± 2.9%), 60-64 yr (24.5 ± 3.6%), 65-69 yr (23.3 ± 3.6%) and ≥70 yr (24.7 ± 2.7%) age groups. Repeat tests on a subset of subjects (walking, n = 43; cycling, n = 37) demonstrated high test-retest reliability [intraclass correlation coefficients (ICC), 0.74-0.86] for all energy outcome measures except cycling net energy expenditure (ICC = 0.54) and net efficiency (ICC = 0.50). Coefficients of variation for all variables ranged from 3.1 to 7.7%. Considerable individual variation in Cw and efficiency was evident, with a ~2-fold difference between the least and most economical/efficient subjects. We conclude that, between 18 and 81 yr, net Cw was only higher for ages ≥70 yr, and that cycling net efficiency was not different across age groups. NEW & NOTEWORTHY This study illustrates that the higher energy cost of walking in older adults is only evident for ages ≥70 yr. For older adults ages 60-69 yr, the energy cost of walking is similar to that of young adults. Cycling efficiency, by contrast, is not different across age groups. Considerable individual variation (∼2-fold) in cycling efficiency and energy cost of walking is observed in young and older adults.

  15. Rapid Cycling and Its Treatment

    Science.gov (United States)

    ... Announcements Public Service Announcements Partnering with DBSA Rapid Cycling and its Treatment What is bipolar disorder? Bipolar ... to Depression and Manic Depression . What is rapid cycling? Rapid cycling is defined as four or more ...

  16. The Effect of Cycling Intensity on Cycling Economy During Seated and Standing Cycling.

    Science.gov (United States)

    Arkesteijn, Marco; Jobson, Simon; Hopker, James; Passfield, Louis

    2016-10-01

    Previous research has shown that cycling in a standing position reduces cycling economy compared with seated cycling. It is unknown whether the cycling intensity moderates the reduction in cycling economy while standing. The aim was to determine whether the negative effect of standing on cycling economy would be decreased at a higher intensity. Ten cyclists cycled in 8 different conditions. Each condition was either at an intensity of 50% or 70% of maximal aerobic power at a gradient of 4% or 8% and in the seated or standing cycling position. Cycling economy and muscle activation level of 8 leg muscles were recorded. There was an interaction between cycling intensity and position for cycling economy (P = .03), the overall activation of the leg muscles (P = .02), and the activation of the lower leg muscles (P = .05). The interaction showed decreased cycling economy when standing compared with seated cycling, but the difference was reduced at higher intensity. The overall activation of the leg muscles and the lower leg muscles, respectively, increased and decreased, but the differences between standing and seated cycling were reduced at higher intensity. Cycling economy was lower during standing cycling than seated cycling, but the difference in economy diminishes when cycling intensity increases. Activation of the lower leg muscles did not explain the lower cycling economy while standing. The increased overall activation, therefore, suggests that increased activation of the upper leg muscles explains part of the lower cycling economy while standing.

  17. Effect of work:rest cycle duration on [Formula: see text] fluctuations during intermittent exercise.

    Science.gov (United States)

    Combes, Adrien; Dekerle, Jeanne; Bougault, Valérie; Daussin, Frédéric N

    2017-01-01

    The succession of on-transient phases that induce a repetition of metabolic changes is a possible mechanism responsible for the greater response to intermittent training (IT). The objective of this study was to quantify [Formula: see text] fluctuations during intermittent exercise characterised by the same work:rest ratio, but different durations and identify which duration leads to the greatest fluctuations. Ten participants (24 ± 5 years; [Formula: see text]: 42 ± 7 mL·min(-1)·kg(-1)) performed (1) an incremental test to exhaustion to determine peak work rate (WRpeak) and oxygen uptake ([Formula: see text]), (2), and three 1 h intermittent exercises alternating work period at 70% WRpeak with passive recovery period of different 1:1 work:recovery duty cycles (30 s:30 s, 60 s:60 s, 120 s:120 s). [Formula: see text] response analysis revealed differences in the fluctuations across the intermittent conditions despite an identical total energy expenditure. The sum of the cycle's nadir-to-peak [Formula: see text] differences (ΣΔ[Formula: see text]) and the oxygen fluctuation index (OFI) were both greater in the 60 s:60 s condition (ΣΔ[Formula: see text]: +38% ± 13% and +19% ± 18% vs. 120 s:120 s and 30 s:30 s, P intermittent condition associated with the greatest disturbances: the 60 s:60 s duty cycle induces more [Formula: see text] fluctuations. The present findings also demonstrate that the selection of the duty cycle duration for submaximal intermittent exercise (70% of WRpeak) prescription is of interest to produce high [Formula: see text] fluctuations.

  18. Modifications in activation of lower limb muscles as a function of initial foot position in cycling.

    Science.gov (United States)

    Padulo, Johnny; Powell, Douglas W; Ardigò, Luca P; Viggiano, Davide

    2015-08-01

    Cyclic movements, such as walking/cycling, require the activity of spinal-circuits, the central-pattern-generators (CPG). To our knowledge little work has been done to investigate the activation of these circuits, e.g., the muscular and kinematic activity during cycling initiation. This study aims to detail the muscle output properties as a function of the initial lower limb-position using a simple cycling paradigm. Therefore, subjects were required to pedal on a cycle-ergometer in seated position starting at different-crank-angles (0-150°). Surface-electromyography was recorded from the gluteus major (GL), vastus lateralis (VL), and gastrocnemius medialis (GM), while crank position was recorded using a linear-encoder. Gluteus major peak-activity (PA) occurred at 65.0±12.4° when starting with 0° initial crank position (ICP), while occurred maximally at 110.5±2.9 when starting with 70° ICP. Vastus lateralis PA occurred at 40.7±8.8° with 0° ICP, whereas with 70° ICP PA occurred at 103.4±4.0°. Similarly, GM PA occurred at 112.0±10.7° with 0° ICP, whereas with 70° ICP PA occurred at 142.5±4.2° PA. Gluteus major and gastrocnemius medialis showed similar PA phase shifts, which may suggest they are controlled by same local circuitry, in agreement with their common spinal origin, i.e., motoneurons pool in S1-S2. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Effects of music on work-rate distribution during a cycling time trial.

    Science.gov (United States)

    Atkinson, G; Wilson, D; Eubank, M

    2004-11-01

    Previous research work on the ergogenic effects of music has mainly involved constant power tests to exhaustion as dependent variables. Time trials are more externally valid than constant power tests, may be more reliable and allow the distribution of self-selected work-rate to be explored. We examined whether music improved starting, finishing and/or overall power during a 10-km cycling time trial, and whether heart rate and subjective responses to this time trial were altered by music. Sixteen participants performed two 10-km time trials on a Cybex cycle ergometer with, and without, the presence of a form of dance music known as "trance" (tempo = 142 beats x min (-1), volume at ear = 87 dB). Participants also completed the Brunel music rating inventory (BMRI) after each time trial in the music condition. The mean +/- SD time to complete the time trial was 1030 +/- 79 s in the music condition compared to 1052 +/- 77 s without music (95 % CI of difference = 10 to 34 s, p = 0.001). Nevertheless, ratings of perceived exertion were consistently (0.8 units) higher throughout the time trial with music (p music-induced increases in cycling speed and heart rate were observed in the first 3 km of the time trial. After completion of the BMRI, participants rated the "tempo" and "rhythm" of the music as more motivating than the "harmony" and "melody" aspects. These results suggest that music improves cycling speed mostly in the first few minutes of a 10-km time trial. In contrast to the findings of previous research, which suggested that music lowers perceived exertion at a constant work-rate, the participants in our time trials selected higher work-rates with music, whilst at the same time perceived these work-rates as being harder than without music.

  20. Variação da pressão intraocular após teste submáximo de força no treinamento resistido Intraocular pressure variation after submaximal strength test in resistance training

    Directory of Open Access Journals (Sweden)

    Marcelo Conte

    2009-06-01

    Full Text Available OBJETIVO: Verificar a variação da pressão intraocular (PIO decorrente da aplicação do teste de predição para uma repetição máxima (1RM. MÉTODOS: Foram avaliados em estudo observacional 145 calouros (22,04 ± 4,17 anos; de ambos os sexos do curso de Educação Física da Escola Superior de Educação Física de Jundiaí (ESEFJ. Os critérios de exclusão foram: opacidade de meios, alteração de globo ocular ou ausência de globo ocular. Todos os participantes assinaram o Termo de Consentimento Livre e Esclarecido. A avaliação da PIO foi determinada por duas medidas consecutivas com o tonômetro de Perkins: i pré-teste: antes do teste de 1RM e ii pós-teste: logo após a realização do teste. O teste de 1RM consistiu em predizer o valor de uma repetição máxima através de repetições até a fadiga. Foram utilizados os seguintes exercícios resistidos: supino, pulley dorsal, desenvolvimento, rosca direta e leg press 45º. Como procedimento estatístico foi empregado o teste "t" de Student pareado. RESULTADOS: Ocorreu redução da PIO após a realização do teste de predição de 1RM: 13,48 ± 3,32 vs.10,20 ± 3,72 mmHg (pPURPOSE: To verify the intraocular pressure (IOP after sub-maximal strength test. METHODS: 145 Physical Education freshmen (22.04 ± 4.17 years old; female and male from Superior Physical Education School of Jundiaí (ESEFJ were evaluated in an observacional study. The exclusion criteria were: media opacity and eyeball absence or changes. All subjects agreed to take part in this research and signed up the Informed Consent. IOP was measured by Perkins tonometer: i pretest: just before the submaximal strength test performance and ii post-test: immediately after the strength test. The strength test consisted in the one-repetition-maximum-assessment through repetition until fatigue. Resistance training exercises such as bench press, pulley dorsal high, shoulder press, arm curl and leg press 45º were performed

  1. Efeitos cardiovasculares da abstinência do fumo no repouso e durante o exercício submáximo em mulheres jovens fumantes Cardiovascular effects of smoking abstinence at rest and during submaximal exercise in young female smokers

    Directory of Open Access Journals (Sweden)

    Demilto Yamaguchi da Pureza

    2007-10-01

    Full Text Available OBJETIVO: O objetivo do presente estudo foi verificar o efeito da abstinência do fumo nas respostas cardiovasculares ao exercício físico progressivo submáximo em mulheres sedentárias fumantes. MÉTODOS: A pressão arterial sistólica (PAS e diastólica (PAD e a freqüência cardíaca (FC foram medidas de forma não invasiva em mulheres jovens não fumantes (MNF, n = 7 e fumantes (MF, n = 7, sem e com abstinência do fumo por 24 horas, em repouso, durante a realização do teste submáximo em bicicleta ergométrica e na recuperação. RESULTADOS: Em repouso, a PAD e a FC foram maiores nas MF (76 ± 1mmHg e 86 ± 5bpm quando comparadas com as MNF (68 ± 2mmHg e 72 ± 2bpm. Após 24 horas sem o tabaco essas medidas foram normalizadas. Durante o exercício, a PAS e a FC aumentaram nos grupos estudados. A PAD foi maior nas MF (~15% em relação às MNF em todos os estágios do exercício. Na situação de abstinência, a PAD aumentou somente no último estágio de exercício. Na recuperação tanto a PAD quanto a FC foram maiores nas MF, na situação basal e com abstinência de 24h, quando comparadas as MNF. CONCLUSÃO: Estes resultados demonstram que mulheres jovens fumantes apresentam prejuízo em parâmetros hemodinâmicos em repouso e em resposta ao exercício submáximo, os quais, podem ser em parte revertidos pela abstinência em curto prazo do uso do tabaco.OBJECTIVE: The objective of the present study was to verify the effect of tobacco smoking abstinence on cardiovascular responses to progressive submaximal physical exercise in sedentary female smokers. METHODS: Systolic blood pressure (SBP, diastolic blood pressure (DBP and heart rate (HR were non-invasively measured in young non-smoking women (NSW, n = 7 and smoking women (SW, n = 7, with and without tobacco abstinence for 24 hours, at rest, during the accomplishment of a submaximal bicycle ergometric test and recovery period. RESULTS: At rest, DBP and HR were higher in the SW group

  2. Pilot study of the effect of low-cadence functional electrical stimulation cycling after spinal cord injury on thigh girth and strength.

    Science.gov (United States)

    Fornusek, Ché; Davis, Glen Macartney; Russold, Michael Friedrich

    2013-05-01

    To investigate the long-term effects of functional electrical stimulation (FES)-evoked cycle training cadence on leg muscle hypertrophy and electrically evoked strength. Open intervention study. Laboratory setting. Untrained individuals with chronic spinal cord injury (N=8). Six weeks (3d/wk) of training on an isokinetic FES cycle ergometer. For each subject, 1 leg was randomly allocated to cycling at 10 revolutions per minute (rpm) (LOW) for 30min/d, and the other cycling at 50rpm (HIGH) for 30min/d. Pre- and posttraining measurements of lower limb circumference were performed at the distal and middle position of each thigh. Electrically evoked quadriceps muscle torque during an isometric contraction was also assessed. Six weeks of FES cycle training significantly increased thigh girth in both LOW and HIGH groups. At midthigh, girth increases induced by LOW (6.6%±1.2%) were significantly greater than those by HIGH (3.6%±0.8%). LOW also produced greater gains in electrically evoked isometric torque than HIGH after training. These results suggest that lower pedaling cadences evoke greater muscle hypertrophy and electrically stimulated muscle strength compared with higher cadences. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  3. Acute effects of a thermogenic nutritional supplement on cycling time to exhaustion and muscular strength in college-aged men

    Directory of Open Access Journals (Sweden)

    Beck Travis W

    2009-07-01

    Full Text Available Abstract Background The purpose of the present study was to examine the acute effects of a thermogenic nutritional supplement containing caffeine, capsaicin, bioperine, and niacin on muscular strength and endurance performance. Methods Twenty recreationally-active men (mean ± SD age = 21.5 ± 1.4 years; stature = 178.2 ± 6.3 cm; mass = 76.5 ± 9.9 kg; VO2 PEAK = 3.05 ± 0.59 L/min-1 volunteered to participate in this randomized, double-blinded, placebo-controlled, cross-over study. All testing took place over a three-week period, with each of the 3 laboratory visits separated by 7 days (± 2 hours. During the initial visit, a graded exercise test was performed on a Lode Corival cycle ergometer (Lode, Groningen, Netherlands until exhaustion (increase of 25 W every 2 min to determine the maximum power output (W at the VO2 PEAK (Parvo Medics TrueOne® 2400 Metabolic Measurement System, Sandy, Utah. In addition, one-repetition maximum (1-RM strength was assessed using the bench press (BP and leg press (LP exercises. During visits 2 and 3, the subjects were asked to consume a capsule containing either the active supplement (200 mg caffeine, 33.34 mg capsaicin, 5 mg bioperine, and 20 mg niacin or the placebo (175 mg of calcium carbonate, 160 mg of microcrystalline cellulose, 5 mg of stearic acid, and 5 mg of magnesium stearate in an identical capsule 30 min prior to the testing. Testing included a time-to-exhaustion (TTE ride on a cycle ergometer at 80% of the previously-determined power output at VO2 PEAK followed by 1-RM LP and BP tests. Results There were no differences (p > 0.05 between the active and placebo trials for BP, LP, or TTE. However, for the BP and LP scores, the baseline values (visit 1 were less than the values recorded during visits 2 and 3 (p ≤ 0.05. Conclusion Our findings indicated that the active supplement containing caffeine, capsaicin, bioperine, and niacin did not alter muscular strength or cycling endurance when compared

  4. Combination of sago and soy-protein supplementation during endurance cycling exercise and subsequent high-intensity endurance capacity.

    Science.gov (United States)

    Ghosh, Asok Kumar; Rahaman, A Abdul; Singh, Rabindarjeet

    2010-06-01

    The purpose of the study was to investigate whether a combination of sago and soy protein ingested during moderate-intensity cycling exercise can improve subsequent high-intensity endurance capacity compared with a carbohydrate in the form of sago and with a placebo. The participants were 8 male recreational cyclists with age, weight, and VO2max of 21.5 +/- 1.1 yr, 63.3 +/- 2.4 kg, and 39.9 +/- 1.1 ml . kg(-1) . min(-1), respectively. The design of the study was a randomized, double-blind placebo-controlled crossover comprising 60 min of exercise on a cycle ergometer at 60% VO2max followed by a time-to-exhaustion ride at 90% VO2max. The sago feeding provided 60 g of carbohydrate, and the sago-soy combination provided 52.5 g of carbohydrate and 15 g of protein, both at 20-min intervals during exercise. Times to exhaustion for the placebo, sago, and sago-soy supplementations were 4.09 +/- 1.28, 5.49 +/- 1.20, and 7.53 +/- 2.02 min, respectively. Sago-soy supplementation increased endurance by 84% (44-140%; p sago, respectively. The plasma insulin response was elevated above that with placebo during sago and sago-soy supplementations. The authors conclude that a combination of sago and soy protein can delay fatigue during high-intensity cycling.

  5. Helium process cycle

    Science.gov (United States)

    Ganni, Venkatarao

    2008-08-12

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  6. The global sulfur cycle

    Science.gov (United States)

    Sagan, D. (Editor)

    1985-01-01

    The results of the planetary biology microbial ecology's 1984 Summer Research Program, which examined various aspects of the global sulfur cycle are summarized. Ways in which sulfur flows through the many living and chemical species that inhabit the surface of the Earth were investigated. Major topics studied include: (1) sulfur cycling and metabolism of phototropic and filamentous sulfur bacteria; (2) sulfur reduction in sediments of marine and evaporite environments; (3) recent cyanobacterial mats; (4) microanalysis of community metabolism in proximity to the photic zone in potential stromatolites; and (5) formation and activity of microbial biofilms on metal sulfides and other mineral surfaces. Relationships between the global sulfur cycle and the understanding of the early evolution of the Earth and biosphere and current processes that affect global habitability are stressed.

  7. CO2 cycle

    Science.gov (United States)

    Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

    2017-01-01

    This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

  8. Revenue cycle management.

    Science.gov (United States)

    Manley, Ray; Satiani, Bhagwan

    2009-11-01

    With the widening gap between overhead expenses and reimbursement, management of the revenue cycle is a critical part of a successful vascular surgery practice. It is important to review the data on all the components of the revenue cycle: payer contracting, appointment scheduling, preregistration, registration process, coding and capturing charges, proper billing of patients and insurers, follow-up of accounts receivable, and finally using appropriate benchmarking. The industry benchmarks used should be those of peers in identical groups. Warning signs of poor performance are discussed enabling the practice to formulate a performance improvement plan.

  9. Menstrual cycle pattern and fertility

    DEFF Research Database (Denmark)

    Kolstad, Henrik A.; Bonde, Jens Peter; Hjøllund, Niels Henrik

    1999-01-01

    To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss.......To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss....

  10. Educational Business Cycles

    DEFF Research Database (Denmark)

    Tepe, Markus; Vanhuysse, Pieter

    2009-01-01

    Strong institutional constraints and better-informed voters may lead re-election seeking incumbents to shift the use of political business cycle mechanisms away from monetary and fiscal policy towards other policy domains that are more easily manipulable, targetable, and timeable. We investigate...

  11. THE EUROPEAN BUSINESS CYCLE

    Directory of Open Access Journals (Sweden)

    Ignat Ion

    2009-05-01

    Full Text Available The construction of European Monetary Union has raised several questions about the existence of a common business cycle, a European one. The lack of cyclical synchronization would complicate the monetary and fiscal policies in the Union, being a negative

  12. Reasoning with Causal Cycles

    Science.gov (United States)

    Rehder, Bob

    2017-01-01

    This article assesses how people reason with categories whose features are related in causal cycles. Whereas models based on causal graphical models (CGMs) have enjoyed success modeling category-based judgments as well as a number of other cognitive phenomena, CGMs are only able to represent causal structures that are acyclic. A number of new…

  13. LIFE-CYCLE ASSESSMENT

    Science.gov (United States)

    Life Cycle Assessment, or LCA, is an environmental accounting and mangement approach that consider all the aspects of resource use and environmental releases associated with an industrial system from cradle-to-grave. Specifically, it is a holistic view of environmental interacti...

  14. The Degree Cycle

    DEFF Research Database (Denmark)

    Wood, Johanna

    2016-01-01

    The grammaticalization of the demonstratives this, that and thus are investigated with respect to their functions as degree adverbs using empirical data from dictionaries and historical and modern corpora. It is first argued that thus participates in the CP cycle. With respect to this and that...

  15. Educational Business Cycles

    DEFF Research Database (Denmark)

    Tepe, Markus; Vanhuysse, Pieter

    Strong institutional constraints and better-informed voters may lead re-election seeking incumbents to shift the use of political business cycle mechanisms away from monetary and fiscal policy towards other policy domains that are more easily manipulable, targetable, and timeable. We investigate...

  16. Econometric Business Cycle Research

    NARCIS (Netherlands)

    J. Tinbergen (Jan)

    1940-01-01

    textabstractAlso published in: G. Haberler (Ed.), Readings in Business Cycles Theory, Blakiston, Philadelphia, 1944, pp. 61-86, in: Adrian C. Darnell (Ed.), The History of Econometrics, Vol. 2, Edward Elgar, Aldershot, 1994, pp. 230-247 and in: David F. Hendry and Mary S. Morgan (Eds), The

  17. Assisted Cycling Tours

    Science.gov (United States)

    Hollingsworth, Jan Carter

    2008-01-01

    This article discusses Assisted Cycling Tours (ACT), a Westminster, Colorado based 501(c)3, non-profit that is offering the joy of bicycle tours in breathtaking, scenic locations to children and adults with developmental and physical disabilities and their families. ACT was founded by Bob Matter and his son David with a goal of opening up the…

  18. Mosquito Life Cycle

    Science.gov (United States)

    Knowing the stages of the mosquito's life will help you prevent mosquitoes around your home and help you choose the right pesticides for your needs, if you decide to use them. All mosquito species go through four distinct stages during their live cycle.

  19. Big Data and Cycling

    NARCIS (Netherlands)

    Romanillos, Gustavo; Zaltz Austwick, Martin; Ettema, Dick; De Kruijf, Joost

    2016-01-01

    Big Data has begun to create significant impacts in urban and transport planning. This paper covers the explosion in data-driven research on cycling, most of which has occurred in the last ten years. We review the techniques, objectives and findings of a growing number of studies we have classified

  20. The Pneumocystis life cycle

    Directory of Open Access Journals (Sweden)

    Cécile-Marie Aliouat-Denis

    2009-05-01

    Full Text Available First recognised as "schizonts" of Trypanosoma cruzi, Pneumocystis organisms are now considered as part of an early-diverging lineage of Ascomycetes. As no robust long-term culture model is available, most data on the Pneumocystis cell cycle have stemmed from ultrastructural images of infected mammalian lungs. Although most fungi developing in animals do not complete a sexual cycle in vivo, Pneumocystis species constitute one of a few exceptions. Recently, the molecular identification of several key players in the fungal mating pathway has provided further evidence for the existence of conjugation and meiosis in Pneumocystisorganisms. Dynamic follow-up of stage-to-stage transition as well as studies of stage-specific proteins and/or genes would provide a better understanding of the still hypothetical Pneumocystislife cycle. Although difficult to achieve, stage purification seems a reasonable way forward in the absence of efficient culture systems. This mini-review provides a comprehensive overview of the historical milestones leading to the current knowledge available on the Pneumocystis life cycle.

  1. Life Cycle Collection Management

    Directory of Open Access Journals (Sweden)

    Helen Shenton

    2003-09-01

    Full Text Available Life cycle collection management is a way of taking a long-term approach to the responsible stewardship of the British Library's collections and is one of the Library's strategic strands. It defines the different stages in a collection item's existence over time. These stages range from selection and acquisitions processing, cataloguing and press marking, through to preventive conservation, storage and retrieval. Life cycle collection management seeks to identify the costs of each stage in order to show the economic interdependencies between the phases over time. It thereby aims to demonstrate the long-term consequences of what the library takes into its collections, by making explicit the financial and other implications of decisions made at the beginning of the life cycle for the next 100 plus years. This paper describes the work over the past year at the British Library on this complex and complicated subject. It presents the emerging findings and suggests how it can be used for practical reasons (by individual curators and selectors and for economic, governance and political purposes. The paper describes the next steps in the project, for example, on a predictive data model. The British Library is seeking to benchmark itself against comparable organisations in this area. It intends to work with others on specific comparison for example, of life cycle costing of electronic and paper journals, as a prelude to eliding digital and 'traditional' formats.

  2. Apoptosis and cell cycle

    Directory of Open Access Journals (Sweden)

    Petrović Marija

    2014-01-01

    Full Text Available Apoptosis, a form of programmed cell death, is used to eliminate individual cells surrounded by normal cell population. It is a controlled way of cell death in which the cell actively participates by conducting precise, gene-regulated program of self-destruction, that is, cell 'suicide.' Active synthesis of macromolecules is necessary during this process. Death of individual cells is necessary to maintain a balance in living systems, so the process of apoptosis is continuously present in the body, which allows normal development, tissue homeostasis, and many other physiological processes. The molecular mechanisms that regulate apoptosis are functionally linked to other cellular mechanisms, such as control of the cell cycle, cell proliferation and differentiation, genomic stability and cellular metabolism. Damage to the DNA molecule, caused both spontaneously and under the influence of various chemical and physical agents, leads to the cell cycle arrest and activation of mechanisms that repair the damage. Depending on the type and extent of the damage, the cell either continues progression through the cell cycle, or activates the mechanisms that lead to apoptosis. Disturbances in the regulation of apoptosis and cell cycle present the molecular and biological basis of many diseases. Because of the importance of these processes during the development and progression of tumors, their use as biological markers is one of the main strategies in the formation of therapeutic approaches for the treatment of cancer.

  3. Privatization and nationalization cycles

    OpenAIRE

    Chang, Roberto; Hevia, Constantino; Loayza, Norman

    2009-01-01

    This paper studies the cycles of nationalization and privatization in resource-rich economies as a prime instance of unstable institutional reform. The authors discuss the available evidence on the drivers and consequences of privatization and nationalization, review the existing literature, and present illustrative case studies. This leads to the main contribution of the paper: a static a...

  4. Re-Cycling

    Science.gov (United States)

    Brown, Robert W.; Covault, Corbin E.

    2015-01-01

    An old comedy routine on Saturday Night Live by Father Guido Sarducci introduced a "Five-Minute University," because five minutes is all that's remembered after graduation anyway. In counterpoint, we discuss "cycling," a teaching method for memory enhancement. Our principal implementation consists of offering a simple version…

  5. The Science of Cycling

    Science.gov (United States)

    Crompton, Zoe; Daniels, Shelley

    2014-01-01

    Children are engaged by finding out about science in the real world (Harlen, 2010). Many children will be cyclists or will have seen or heard about the success of British cyclists in the Olympics and the Tour de France. This makes cycling a good hook to draw children into learning science. It is also a good cross-curricular topic, with strong…

  6. The Geologic Nitrogen Cycle

    Science.gov (United States)

    Johnson, B. W.; Goldblatt, C.

    2013-12-01

    N2 is the dominant gas in Earth's atmosphere, and has been so through the majority of the planet's history. Originally thought to only be cycled in significant amounts through the biosphere, it is becoming increasingly clear that a large degree of geologic cycling can occur as well. N is present in crustal rocks at 10s to 100s of ppm and in the mantle at 1s to perhaps 10s of ppm. In light of new data, we present an Earth-system perspective of the modern N cycle, an updated N budget for the silicate Earth, and venture to explain the evolution of the N cycle over time. In an fashion similar to C, N has a fast, biologically mediated cycle and a slower cycle driven by plate tectonics. Bacteria fix N2 from the atmosphere into bioavailable forms. N is then cycled through the food chain, either by direct consumption of N-fixing bacteria, as NH4+ (the primary waste form), or NO3- (the most common inorganic species in the modern ocean). Some organic material settles as sediment on the ocean floor. In anoxic sediments, NH4+ dominates; due to similar ionic radii, it can readily substitute for K+ in mineral lattices, both in sedimentary rocks and in oceanic lithosphere. Once it enters a subduction zone, N may either be volatilized and returned to the atmosphere at arc volcanoes as N2 or N2O, sequestered into intrusive igneous rocks (as NH4+?), or subducted deep into the mantle, likely as NH4+. Mounting evidence indicates that a significant amount of N may be sequestered into the solid Earth, where it may remain for long periods (100s m.y.) before being returned to the atmosphere/biosphere by volcanism or weathering. The magnitude fluxes into the solid Earth and size of geologic N reservoirs are poorly constrained. The size of the N reservoirs contained in the solid Earth directly affects the evolution of Earth's atmosphere. It is possible that N now sequestered in the solid Earth was once in the atmosphere, which would have resulted in a higher atmospheric pressure, and

  7. Effects of reducing exposure to air pollution on submaximal cardiopulmonary test in patients with heart failure: Analysis of the randomized, double-blind and controlled FILTER-HF trial.

    Science.gov (United States)

    Vieira, Jefferson L; Guimaraes, Guilherme V; de Andre, Paulo A; Saldiva, Paulo H Nascimento; Bocchi, Edimar A

    2016-07-15

    Air pollution exposure could mitigate the health benefits of exercise in patients with heart failure (HF). We tested the effects of a respiratory filter on HF patients exposed to air pollution during exercise. Ancillary analysis of the FILTER-HF trial, focused on the exercise outcomes. In a randomized, double-blind, 3-way crossover design, 26 HF patients and 15 control volunteers were exposed to clean air, unfiltered dilute diesel engine exhaust (DE), or filtered DE for 6min during a submaximal cardiopulmonary testing in a controlled-exposure facility. Prospectively collected data included six-minute walking test [6mwt], VO2, VE/VCO2 Slope, O2Pulse, pulmonary ventilation [VE], tidal volume, VD/Vt, oxyhemoglobin saturation and CO2-rebreathing. Compared to clean air, DE adversely affected VO2 (11.0±3.9 vs. 8.4±2.8ml/kg/min; peffects of pollution on VO2 and O2Pulse. Given the worldwide prevalence of exposure to traffic-related air pollution, these findings are relevant for public health especially in this highly susceptible population. The filter intervention holds great promise that needs to be tested in future studies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Vascular Dynamics and Peripheral Oxygen Uptake in Obese Individuals during Progressive Physical Exercise.

    Science.gov (United States)

    Brunani, Amelia; Lanzi, Stefano; Codecasa, Franco; Cornacchia, Mauro; Maestrini, Sabrina; Soranna, Davide; Zambon, Antonella; Cattaldo, Stefania; Fanari, Paolo; Malatesta, Davide; Salvadori, Alberto

    2017-01-01

    Obese men show higher O2 consumption than lean men during physical exercise, with a trend toward higher peripheral O2 extraction; this is probably due to their larger muscle mass. The aim of this study was to examine this phenomenon by measuring 2 vasoactive substances, endothelin-1 (ET-1) and nitric oxide (NO), during a progressive submaximal exercise. Seventeen obese (body mass index [BMI] 38.6) and 15 lean (BMI 22.5) men performed a maximal progressive cycle ergometer exercise to determine peak power output (PPO) and peak O2 consumption (V∙O2peak); thereafter, they performed a submaximal cycle ergometer incremental test (every 6 min) at the same percentage of V∙O2peak until they reached 57.5% PPO. Blood samples were collected at rest and at the end of every step to measure ET-1 and NO concentrations. At rest, the ET-1 and NO concentrations in obese men and lean controls were the same. However, during exercise, the ET-1 concentration at each step was significantly lower (p < 0.05) in the obese group. There was no significant difference in NO concentration between the 2 groups, although the increase at the beginning of the exercise session was faster in obese individuals. During submaximal exercise, end-tidal O2 pressure (PETO2) was lower in the obese group, with a significant difference in the PETO2/fat-free mass ratio at each step. ET-1 and NO levels during physical exercise are different in obese versus lean men. This may support the notion that increased O2 consumption in obesity is due to different behaviors of the cardiorespiratory and circulatory systems. © 2017 S. Karger AG, Basel.

  9. Monitoring Perceived Stress and Recovery in Relation to Cycling Performance in Female Athletes.

    Science.gov (United States)

    Otter, R T A; Brink, M S; van der Does, H T D; Lemmink, K A P M

    2016-01-01

    The purpose was to investigate perceived stress and recovery related to cycling performance of female athletes over one full year. 20 female athletes (age, 27±8 years; ˙VO2max, 50.3±4.6 mL·kg(-1)·min(-1)) were measured 8 times in one year to determine perceived stress and recovery (RESTQ-Sport) in relation to cycling performance (Lamberts and Lambert Submaximal Cycle Test (LSCT)). All 19 RESTQ-Sport scales were calculated and scores of the 4 main categories were determined (i. e., general stress, general recovery, sport-specific stress and sport-specific recovery). A balance score of total stress and recovery was calculated by recovery-stress. Power at the second stage (P80), third stage (P90) and heart rate recovery (HRR60 s) of the LSCT were determined as performance parameters. 110 RESTQ-Sports and LSCTs were analysed using a multilevel approach (random intercepts model). Higher self-efficacy was related to improvement of all performance parameters. Higher total recovery stress, and lower emotional stress were related to improvement of P90 and HRR60 s. Higher sport-specific recovery was related to P80, higher general stress, fatigue and physical complaints were related to decreased P90 and higher social stress and injury were related to decreased HRR60 s. Improved perceived recovery and stress contributed to an improved performance. Relevant information could be provided by monitoring changes in perceived stress and recovery of female athletes. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Absence of Respiratory Muscle Fatigue in High-Intensity Continuous or Interval Cycling Exercise.

    Science.gov (United States)

    Kurti, Stephanie P; Smith, Joshua R; Emerson, Sam R; Castinado, Kenneth M; Harms, Craig A

    2015-11-01

    Respiratory muscle fatigue (RMF) occurs during prolonged exercise (∼15-20 minutes) at >85% V[Combining Dot Above]O2max. However, RMF has been reported to occur in ∼3-6 minutes in various modes of exercise at a high intensity. It is not known if continuous cycling exercise vs. repeated bouts of high-intensity interval training (HIT) at >85% V[Combining Dot Above]O2max will lead to RMF. We hypothesized that RMF would occur after a constant load test and would be present before end exercise in an HIT protocol. Eight moderately active healthy men (21.7 ± 1.7 years; 181.3 ± 5.2 cm; 81.3 ± 2.3 kg) completed a V[Combining Dot Above]O2max test on a cycle ergometer. Subjects then completed 2 bouts of HIT (7 × 1 minute, 2-minute recovery between intervals) and 3 bouts of continuous exercise (CE) tests at 90% of peak power (determined from an incremental exercise test to exhaustion). Maximal inspiratory pressure (PIMAX) and expiratory pressure (PEMAX) were measured pre- and post-exercise for both HIT and CE and after each interval during HIT. Decreases in postexercise PIMAX and PEMAX compared with baseline were used to determine RMF. There were no differences (p > 0.05) in PIMAX or PEMAX pre- to post-exercise for HIT (PIMAX pre: 134 ± 51, post: 135 ± 50 cmH2O; PEMAX pre: 143 ± 41, post: 148 ± 46 cmH2O) or CE (PIMAX pre: 135 ± 54, post: 133 ± 52 cmH2O; PEMAX pre: 146 ± 46, post: 148 ± 46 cmH2O) indicating RMF was not present following CE and HIT. These data suggest that repeated high-intensity cycling exercise at 90% peak power in a CE or HIT protocol does not lead to RMF.

  11. Comparison of strategies and performance of functional electrical stimulation cycling in spinal cord injury pilots for competition in the first ever CYBATHLON

    Directory of Open Access Journals (Sweden)

    Christine Azevedo Coste

    2017-12-01

    Full Text Available Functional Electrical Stimulation (FES can elicit muscular contraction and restore motor function in paralyzed limbs. FES is a rehabilitation technique applied to various sensorimotor deficiencies and in different functional situations, e.g. grasping, walking, standing, transfer, cycling and rowing. FES can be combined with mechanical devices. FES-assisted cycling is mainly used in clinical environments for training sessions on cycle ergometers, but it has also been adapted for mobile devices, usually tricycles. In October 2016, twelve teams participated in the CYBATHLON competition in the FES-cycling discipline for persons with motor-complete spinal cord injury. It was the first event of this kind and a wide variety of strategies, techniques and designs were employed by the different teams in the competition. The approaches of the teams are detailed in this special issue. We hope that the knowledge contained herein, together with recent positive results of FES for denervated degenerating muscles, will provide a solid basis to encourage improvements in FES equipment and open new opportunities for many patients in need of safe and effective FES management. We hope to see further developments and/or the benefit of new training strategies at future FES competitions, e.g. at the Cybathlon 2020 (www.cybathlon.ethz.ch.

  12. Caffeine Affects Time to Exhaustion and Substrate Oxidation during Cycling at Maximal Lactate Steady State

    Directory of Open Access Journals (Sweden)

    Rogério Santos de Oliveira Cruz

    2015-06-01

    Full Text Available This study analyzed the effects of caffeine intake on whole-body substrate metabolism and exercise tolerance during cycling by using a more individualized intensity for merging the subjects into homogeneous metabolic responses (the workload associated with the maximal lactate steady state—MLSS. MLSS was firstly determined in eight active males (25 ± 4 years, 176 ± 7 cm, 77 ± 11 kg using from two to four constant-load tests of 30 min. On two following occasions, participants performed a test until exhaustion at the MLSS workload 1 h after taking either 6 mg/kg of body mass of caffeine or placebo (dextrose, in a randomized, double-blinded manner. Respiratory exchange ratio was calculated from gas exchange measurements. There was an improvement of 22.7% in time to exhaustion at MLSS workload following caffeine ingestion (95% confidence limits of ±10.3%, p = 0.002, which was accompanied by decrease in respiratory exchange ratio (p = 0.001. These results reinforce findings indicating that sparing of the endogenous carbohydrate stores could be one of the several physiological effects of caffeine during submaximal performance around 1 h.

  13. Estimation of sweat rates during cycling exercise by means of the closed chamber condenser technology.

    Science.gov (United States)

    Clarys, P; Clijsen, R; Barel, A O; Schouteden, R; van Olst, B; Aerenhouts, D

    2017-02-01

    Knowledge of local sweating patterns is of importance in occupational and exercise physiology settings. The recently developed closed chamber condenser technology (Biox Aquaflux ® ) allows the measurement of evaporative skin water loss with a greater measurement capacity (up to 1325 g/h/m 2 ) compared to traditional evaporimeters. The aim of this study was to evaluate the applicability of the Biox Aquaflux ® to estimate sweat production during exercise. Fourteen healthy subjects performed a 20-min cycle ergometer trial at respectively 55% heart rate (HR reserve and 75% HR reserve . Sweat production was estimated by measuring body weight before and after exercise, by calculating the amount of sweat collected in a patch, and by measuring the water flux (in g/h/m 2 ) with the Biox Aquaflux ® instrument. The Biox Aquaflux ® instrument allowed the follow up of sweat kinetics at both intensities. Correlations between the measurement methods were all significant for the 75% HR reserve trial (with r ranging from 0.68 to 0.76) whilst for the 55% HR reserve a significant relation was detected between the patch method and the Biox Aquaflux ® only (with r ranging from 0.41 to 0.79). The Biox Aquaflux ® instrument is a practical and direct method for the estimation of local sweat rates under field conditions. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Effects of petrissage massage on fatigue and exercise performance following intensive cycle pedalling.

    Science.gov (United States)

    Ogai, R; Yamane, M; Matsumoto, T; Kosaka, M

    2008-10-01

    Petrissage is assumed to influence circulation as well as interstitial drainage of both superficial and deep tissues. To study its effect it was applied between consecutive bouts of supramaximal exercise performed by the lower leg muscles. Subjects were 11 healthy female students actively engaged in sports. Exercise bouts of ergometer cycling at loads determined individually (0.075 kp x body weight (kg)) for 5 s repeated eight times at intervals of 20 s had to be performed twice on an experimental day with 35 min intermittent bed rest. Each subject was investigated on two occasions with a minimum interval of 1 week, once without (control, CO) and once with 10 min petrissage (massage, MA) of the exercising lower leg during the bed rest phase. Effects of exercise bouts on blood lactate, muscle stiffness and perceived lower limb fatigue and their recovery before and after the second exercise bout were determined. For the first exercise bouts total power did not differ between MA and CO. Courses of blood lactate did not differ between MA and CO. However, recovery from measured muscle stiffness (pperformance independent of blood lactate but in correlation with improved recovery from muscle stiffness and perceived lower limb fatigue.

  15. Archaea in biogeochemical cycles.

    Science.gov (United States)

    Offre, Pierre; Spang, Anja; Schleper, Christa

    2013-01-01

    Archaea constitute a considerable fraction of the microbial biomass on Earth. Like Bacteria they have evolved a variety of energy metabolisms using organic and/or inorganic electron donors and acceptors, and many of them are able to fix carbon from inorganic sources. Archaea thus play crucial roles in the Earth's global geochemical cycles and influence greenhouse gas emissions. Methanogenesis and anaerobic methane oxidation are important steps in the carbon cycle; both are performed exclusively by anaerobic archaea. Oxidation of ammonia to nitrite is performed by Thaumarchaeota. They represent the only archaeal group that resides in large numbers in the global aerobic terrestrial and marine environments on Earth. Sulfur-dependent archaea are confined mostly to hot environments, but metal leaching by acidophiles and reduction of sulfate by anaerobic, nonthermophilic methane oxidizers have a potential impact on the environment. The metabolisms of a large number of archaea, in particular those dominating the subsurface, remain to be explored.

  16. Life Cycle Sustainability Dashboard

    DEFF Research Database (Denmark)

    Traverso, Marzia; Finkbeiner, Matthias; Jørgensen, Andreas

    2012-01-01

    One method to assess the sustainability performance of products is life cycle sustainability assessment (LCSA), which assesses product performance considering the environmental,economic, and social dimensions of the life cycle. The results of LCSA can be used to compare different products...... or to support decision making toward sustainable production and consumption. In both cases, LCSA results could be too disaggregated and consequently too difficult to understand and interpret by decision makers. As non-experts are usually the target audience of experts and scientists, and are also involved...... in decision-making processes, the necessity for a straightforward but comprehensive presentation of LCSA results is becoming strategically important. The implementation of the dashboard of sustainability proposed in this article offers a possible solution. An outstanding characteristic of the dashboard...

  17. Carbon cycle makeover

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Kump, Lee R.

    2013-01-01

    In 1845, the French chemist and mining engineer Jacques-Joseph Ebelman figured out why Earth's atmosphere contains oxygen (1). Oxygen is produced by plants during photosynthesis, but almost all of this oxygen is used again in respiration. Ebelman reasoned that small amounts of organic matter rema...... geochemical cycle. But Earth is an old planet, and oxygen levels have changed through time (2). On page 540 of this issue, Schrag et al. (3) challenge the most commonly used geochemical approach to assess long-term changes in the coupled oxygen and carbon cycles....... remaining in sediments after respiration leave a residual of oxygen in the atmosphere. The source of oxygen to the atmosphere represented by organic matter burial is balanced by oxygen sinks associated with rock weathering and chemical reaction with volcanic gases. This is the long-term carbon and oxygen...

  18. Cycling and erectile dysfunction

    Directory of Open Access Journals (Sweden)

    Ina Šibli

    2015-01-01

    Full Text Available Abstract: For many years medical studies have implicated bicycle riding is causing erectile dysfunction (ED in association with higher perineal pressure. This review focuses upon epidemiological studies assesing the impact of cycling on ED, pathogenesis of ED in cyclists  as well as on research considering changes of perineal pressure, hemodynamics, and nerve conduction when cycling. Investigestors were also interested in different saddle sizes, materials and geometry and also in the impact of saddle and riders position on changes to the perineum. Research on female cyclists is very limited but indicates similar genitourinary disorders as in male cyclists. We also review  research on preventative and therapeutic options regarding bicycle riding and ED.

  19. Assessing Cycling Participation in Australia

    Directory of Open Access Journals (Sweden)

    Chris Rissel

    2013-01-01

    Full Text Available Planning and evaluating cycling programs at a national or state level requires accurate measures of cycling participation. However, recent reports of cycling participation have produced very different estimates. This paper examines the reported rates of cycling in five recent population surveys of cycling. Three surveys (one national and two from Sydney asking respondents when they last rode a bicycle generated cycling participation (cycled in the past year estimates of 29.7%, 34.1% and 28.9%. Two other national surveys which asked participants to recall (unprompted any physical activity done for exercise, recreation or sport in the previous 12 months, estimated cycling in the past year as 11.1% and 6.5%. While unprompted recall of cycling as a type of physical activity generates lower estimates of cycling participation than specific recall questions, both assessment approaches produced similar patterns of cycling by age and sex with both approaches indicating fewer women and older adults cycling. The different question styles most likely explain the substantial discrepancies between the estimates of cycling participation. Some differences are to be expected due to sampling variability, question differences, and regional variation in cycling.

  20. [Microbial geochemical calcium cycle].

    Science.gov (United States)

    Zavarzin, G A

    2002-01-01

    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  1. Unemployment and Business Cycles

    OpenAIRE

    Lawrence J. Christiano; Martin Eichenbaum; Mathias Trabandt

    2013-01-01

    We develop and estimate a general equilibrium search and matching model that accounts for key business cycle properties of macroeconomic aggregates, including labor market variables. In sharp contrast to leading New Keynesian models, we do not impose wage inertia. Instead we derive wage inertia from our specification of how firms and workers negotiate wages. Our model outperforms a variant of the standard New Keynesian Calvo sticky wage model. According to our estimated model, there is a crit...

  2. Skills, sunspots and cycles

    DEFF Research Database (Denmark)

    Busato, Francesco; Marchetti, Enrico

    This paper explores the ability of a class of one-sector,multi-input models to generate indeterminate equilibrium paths, andendogenous cycles, without relying on factors' hoarding. The modelpresents a novel theoretical economic mechanism that supportssunspot-driven expansions without requiring...... upward sloping labordemand schedules. Its distinctive characteristic is that the skillcomposition of aggregate labor demand drives expansionary i.i.d.demand shocks. Next, the model explains the labor market dynamicsfrom the supply side, while endogenizing the capital productivityresponse to changes...

  3. Injuries in Competitive Cycling.

    Science.gov (United States)

    Bohlmann, J T

    1981-05-01

    In brief: There are relatively few injuries in competitive cycling, and abrasions are the most common. In this study most injuries occurred to the left side of the cyclist, and most common causes were flat tires and colliding with other cyclists. The number of injuries decreased as the cyclist gained more experience. Preventive measures include keeping the bicycle in top mechanical condition, wearing strong, durable clothing and a helmet, and knowing how to fall.

  4. Centrifugal Gas Compression Cycle

    Science.gov (United States)

    Fultun, Roy

    2002-11-01

    A centrifuged gas of kinetic, elastic hard spheres compresses isothermally and without flow of heat in a process that reverses free expansion. This theorem follows from stated assumptions via a collection of thought experiments, theorems and other supporting results, and it excludes application of the reversible mechanical adiabatic power law in this context. The existence of an isothermal adiabatic centrifugal compression process makes a three-process cycle possible using a fixed sample of the working gas. The three processes are: adiabatic mechanical expansion and cooling against a piston, isothermal adiabatic centrifugal compression back to the original volume, and isochoric temperature rise back to the original temperature due to an influx of heat. This cycle forms the basis for a Thomson perpetuum mobile that induces a loop of energy flow in an isolated system consisting of a heat bath connectable by a thermal path to the working gas, a mechanical extractor of the gas's internal energy, and a device that uses that mechanical energy and dissipates it as heat back into the heat bath. We present a simple experimental procedure to test the assertion that adiabatic centrifugal compression is isothermal. An energy budget for the cycle provides a criterion for breakeven in the conversion of heat to mechanical energy.

  5. Terrestrial Carbon Cycle Variability.

    Science.gov (United States)

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2 , temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y -1 ) with respect to a large and uncertain background (123 +/- 4 Pg-C y -1 ), and

  6. 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

  7. Anti-inflammatory effects of a special carbohydrate-whey protein cake after exhaustive cycling in humans.

    Science.gov (United States)

    Kerasioti, Efthalia; Stagos, Dimitrios; Jamurtas, Athanasios; Kiskini, Alexandra; Koutedakis, Yiannis; Goutzourelas, Nikos; Pournaras, Spyros; Tsatsakis, Aristidis M; Kouretas, Dimitrios

    2013-11-01

    Intense exercise induces increased levels of pro-inflammatory and anti-inflammatory cytokines. Thus, the purpose of this study was to examine the effects of a special cake (consisting of carbohydrate to whey protein 3.5:1) vs. an isocaloric carbohydrate cake on inflammatory markers after exhaustive cycling in humans. Nine subjects received either the experimental or placebo cake in a counterbalanced fashion using a crossover, double-blind, repeated-measures design. They performed one trial involving a 2h exercise on a cycle ergometer at 60-65% VO2max followed by a 4h recovery and then a second trial involving an 1h exercise at 60-65% VO2max which was increased at 95% VO2max. Blood samples were collected pre-exercise, 30 min and 4h post-exercise, post-time Trial and 48 h post-time Trial. Cakes were consumed immediately post-exercise and every 1h for the next 3h. The results showed that consumption of the experimental cake reduced significantly (p<0.05), 4h post-exercise, the pro-inflammatory protein levels IL-6 and CRP compared to the control group by 50% and 46% respectively. Moreover, in the experimental cake group, the level of the anti-inflammatory cytokine IL-10 was higher by 118%, 4h post-exercise, compared to the control group but not statistically significant. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Effects of pre-exercise listening to slow and fast rhythm music on supramaximal cycle performance and selected metabolic variables.

    Science.gov (United States)

    Yamamoto, T; Ohkuwa, T; Itoh, H; Kitoh, M; Terasawa, J; Tsuda, T; Kitagawa, S; Sato, Y

    2003-07-01

    We examined the effect of listening to two different types of music (with slow and fast rhythm), prior to supramaximal cycle exercise, on performance, heart rate, the concentration of lactate and ammonia in blood, and the concentration of catecholamines in plasma. Six male students participated in this study. After listening to slow rhythm or fast rhythm music for 20 min, the subjects performed supramaximal exercise for 45 s using a cycle ergometer. Listening to slow and fast rhythm music prior to supramaximal exercise did not significantly affect the mean power output. The plasma norepinephrine concentration immediately before the end of listening to slow rhythm music was significantly lower than before listening (p concentration immediately before the end of listening to fast rhythm music was significantly higher than before listening (p music had no effect on blood lactate and ammonia levels or on plasma catecholamine levels following exercise. In conclusion, listening to slow rhythm music decreases the plasma norepinephrine level, and listening to fast rhythm music increases the plasma epinephrine level. The type of music has no impact on power output during exercise.

  9. Menstrual cycle pattern and fertility

    DEFF Research Database (Denmark)

    Kolstad, Henrik A.; Bonde, Jens Peter; Hjøllund, Niels Henrik

    1999-01-01

    OBJECTIVE: To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss. DESIGN: Prospective follow-up study. SETTING: Healthy couples recruited throughout Denmark...

  10. National Urea Cycle Disorders Foundation

    Science.gov (United States)

    ... INGESTING HIGH-PROTEIN FOODS AND PROTEIN SUPPLEMENTS FOR BODYBUILDING : Symptoms of urea cycle disorder went unrecognized as young mother, Meegan Hefford, prepared for a bodybuilding competition. Undiagnosed urea cycle disorders can be triggered ...

  11. GEOSS Water Cycle Integrator

    Science.gov (United States)

    Koike, Toshio; Lawford, Richard; Cripe, Douglas

    2013-04-01

    It is critically important to recognize and co-manage the fundamental linkages across the water-dependent domains; land use, including deforestation; ecosystem services; and food-, energy- and health-securities. Sharing coordinated, comprehensive and sustained observations and information for sound decision-making is a first step; however, to take full advantage of these opportunities, we need to develop an effective collaboration mechanism for working together across different disciplines, sectors and agencies, and thereby gain a holistic view of the continuity between environmentally sustainable development, climate change adaptation and enhanced resilience. To promote effective multi-sectoral, interdisciplinary collaboration based on coordinated and integrated efforts, the intergovernmental Group on Earth Observations (GEO) is implementing the Global Earth Observation System of Systems (GEOSS). A component of GEOSS now under development is the "GEOSS Water Cycle Integrator (WCI)", which integrates Earth observations, modeling, data and information, management systems and education systems. GEOSS/WCI sets up "work benches" by which partners can share data, information and applications in an interoperable way, exchange knowledge and experiences, deepen mutual understanding and work together effectively to ultimately respond to issues of both mitigation and adaptation. (A work bench is a virtual geographical or phenomenological space where experts and managers collaborate to use information to address a problem within that space). GEOSS/WCI enhances the coordination of efforts to strengthen individual, institutional and infrastructure capacities, especially for effective interdisciplinary coordination and integration. GEO has established the GEOSS Asian Water Cycle Initiative (AWCI) and GEOSS African Water Cycle Coordination Initiative (AfWCCI). Through regional, inter-disciplinary, multi-sectoral integration and inter-agency coordination in Asia and Africa, GEOSS

  12. Life Cycle Inventory Analysis

    DEFF Research Database (Denmark)

    Bjørn, Anders; Moltesen, Andreas; Laurent, Alexis

    2017-01-01

    of different sources. The output is a compiled inventory of elementary flows that is used as basis of the subsequent life cycle impact assessment phase. This chapter teaches how to carry out this task through six steps: (1) identifying processes for the LCI model of the product system; (2) planning......The inventory analysis is the third and often most time-consuming part of an LCA. The analysis is guided by the goal and scope definition, and its core activity is the collection and compilation of data on elementary flows from all processes in the studied product system(s) drawing on a combination...

  13. Elementary cycles of time

    Directory of Open Access Journals (Sweden)

    Dolce Donatello

    2013-09-01

    Full Text Available Elementary particles, i.e. the basic constituents of nature, are characterized by quantum recurrences in time. The flow of time of every physical system can be therefore decomposed in elementary cycles of time. This allows us to enforce the local nature of relativistic time, yielding interesting unified descriptions of fundamental aspects of modern physics, as shown in recent publications. Every particle can be regarded as a reference clock with time resolution of the order of the Compton time particle, many orders of magnitude more accurate than the atomic clocks. Here we report basic implications about the resulting notion of time.

  14. The software life cycle

    CERN Document Server

    Ince, Darrel

    1990-01-01

    The Software Life Cycle deals with the software lifecycle, that is, what exactly happens when software is developed. Topics covered include aspects of software engineering, structured techniques of software development, and software project management. The use of mathematics to design and develop computer systems is also discussed. This book is comprised of 20 chapters divided into four sections and begins with an overview of software engineering and software development, paying particular attention to the birth of software engineering and the introduction of formal methods of software develop

  15. Geomicrobiological cycling of antimony

    Science.gov (United States)

    Kulp, T. R.; Terry, L.; Dovick, M. A.; Braiotta, F.

    2013-12-01

    Microbiologically catalyzed oxidation and reduction of toxic metalloids (e.g., As, Se, and Te) generally proceeds much faster than corresponding abiotic reactions. These microbial transformations constitute biogeochemical cycles that control chemical speciation and environmental behavior of metalloids in aqueous environments. Particular progress has been made over the past two decades in documenting microbiological biotransformations of As, which include anaerobic respiratory reduction of As(V) to As(III), oxidation of As(III) to As(V) linked to chemoautotrophy or photoautotrophy, and cellular detoxification pathways. By contrast, microbial interactions with Sb, As's group 15 neighbor and a toxic element of emerging global concern, are poorly understood. Our work with sediment microcosms, enrichment cultures, and bacterial isolates suggests that prokaryotic metabolisms may be similarly important to environmental Sb cycling. Enrichment cultures and isolates from a Sb-contaminated mine site in Idaho exhibited Sb(V)-dependent heterotrophic respiration under anaerobic conditions and Sb(III)-dependent autotrophic growth in the presence of air. Live, anoxic cultures reduced 2 mM Sb(V) to Sb(III) within 5 d, while no activity occurred in killed controls. Sb(V) reduction was stimulated by lactate or acetate and was quantitatively coupled to the oxidation of lactate. The oxidation of radiolabeled 14C-acetate (monitored by GC-GPC) demonstrated Sb(V)-dependent oxidation to 14CO2, suggesting a dissimilatory process. Sb(V) dependent growth in cultures was demonstrated by direct counting. Microbiological reduction of Sb(V) also occurred in anerobic sediment microcosms from an uncontaminated suburban lake, but did not appear to be linked to growth and is interpreted as a mechanism of biological detoxification. Aerobic microcosms and cultures from the Idaho mine oxidized 2 mM Sb(III) to Sb(V) within 7 d and coupled this reaction to cell growth quantified by direct counting. An

  16. The Location of Peak Upper Trapezius Muscle Activity During Submaximal Contractions is not Associated With the Location of Myofascial Trigger Points: New Insights Revealed by High-density Surface EMG.

    Science.gov (United States)

    Barbero, Marco; Falla, Deborah; Mafodda, Luca; Cescon, Corrado; Gatti, Roberto

    2016-12-01

    To apply topographical mapping of the electromyography (EMG) amplitude recorded from the upper trapezius muscle to evaluate the distribution of activity and the location of peak activity during a shoulder elevation task in participants with and without myofascial pain and myofascial trigger points (MTrP) and compare this location with the site of the MTrP. Thirteen participants with myofascial pain and MTrP in the upper trapezius muscle and 12 asymptomatic individuals participated. High-density surface EMG was recorded from the upper trapezius muscle using a matrix of 64 surface electrodes aligned with an anatomic landmark system (ALS). Each participant performed a shoulder elevation task consisting of a series of 30 s ramped contractions to 15% or 60% of their maximal voluntary contraction (MVC) force. Topographical maps of the EMG average rectified value were computed and the peak EMG amplitude during the ramped contractions was identified and its location determined with respect to the ALS. The location of the MTrP was also determined relative to the ALS and Spearman correlation coefficients were used to examine the relationship between MTrP and peak EMG amplitude location. The location of the peak EMG amplitude was significantly (PEMG amplitude during the ramped contractions at either force level (15%: rs=0.039, P=0.9; 60%: rs=-0.087, P=0.778). People with myofascial pain and MTrP displayed a caudal shift of the distribution of upper trapezius muscle activity compared with asymptomatic individuals during a submaximal shoulder elevation task. For the first time, we show that the location of peak muscle activity is not associated with the location of the MTrP.

  17. Heart rate response and parasympathetic modulation during recovery from exercise in boys and men.

    Science.gov (United States)

    Guilkey, Justin P; Overstreet, Matthew; Fernhall, Bo; Mahon, Anthony D

    2014-08-01

    The purpose of this study was to examine the influence of postexercise parasympathetic modulation, measured by heart rate variability (HRV), on heart rate recovery (HRR) in boys (n = 13, 10.1 ± 0.8 years) and men (n = 13, 23.9 ± 1.5 years) following maximal and submaximal exercise. Subjects completed 10 min of supine rest, followed by graded exercise on a cycle ergometer to maximal effort. On a separate day, subjects exercised at an intensity equivalent to ventilatory threshold. Immediately following both exercise bouts, 1-min HRR was assessed in the supine position. HRV was analyzed under controlled breathing during the final 5 min of rest and recovery in the time and frequency domains and transformed to natural log (ln) values. Boys had a greater 1-min HRR than men following maximal (58 ± 8 vs. 47 ± 11 beats·min(-1)) and submaximal (59 ± 8 vs. 47 ± 15 beats·min(-1)) exercise (p 0.05). In conclusion, it appears that greater parasympathetic modulation accounts for greater HRR following maximal exercise in boys versus men. Although submaximal HRR was greater in boys, parasympathetic responses were similar between groups.

  18. Kondratieff's Long-Wave Cycle.

    Science.gov (United States)

    Volland, Craig S.

    1985-01-01

    The legendary Soviet economist's classic work, "Long-Wave Cycle," has been republished. Admirers believe that it explains how the world's economy works. According to Kondratieff, the world economy follows cycles lasting from 48 to 55 years. His cycle theory is discussed. (Author/RM)

  19. Entrepreneurship and the Business Cycle

    NARCIS (Netherlands)

    Ph.D. Koellinger (Philipp); A.R. Thurik (Roy)

    2011-01-01

    textabstractWe find new empirical regularities in the business cycle in a cross-country panel of 22 OECD countries for the period 1972-2007; entrepreneurship Granger-causes the cycles of the world economy. Furthermore, the entrepreneurial cycle is positively affected by the national unemployment

  20. Revenue cycle management: part I.

    Science.gov (United States)

    Crew, Matt

    2006-01-01

    The revenue cycle starts long before a patient is seen and continues until a claim is completely resolved. Each step in the revenue cycle must be clearly defined and easy to follow. Use of various tools such as templates, forms, reports, spreadsheets, and components of your practice management system will help to provide the consistency you need for profitable revenue cycle management.