Search

Your search keyword '"DOREL, Sylvain"' showing total 85 results
Start Over Author "DOREL, Sylvain"
85 results on '"DOREL, Sylvain"'

52. A simple method for measuring power, force, velocity properties, and mechanical effectiveness in sprint running

Author

Samozino, Pierre, Rabita, Giuseppe, Dorel, Sylvain, Slawinski, Jean, Peyrot, Nicolas, Saez de Villareal, Eduardo, Morin, Jean-Benoît, Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM ), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM), Institut national du sport, de l'expertise et de la performance (INSEP), Motricité, interactions, performance EA 4334 / Movement - Interactions - Performance (MIP), Le Mans Université (UM)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université de Nantes (UN)-Université de Nantes (UN), Centre de Recherche sur le Sport et le Mouvement (CeRSM), Université Paris Nanterre (UPN), Déterminants Interculturels de la Motricité et de la Performance Sportive (DIMPS), Université de La Réunion (UR), Universidad Pablo de Olavide [Sevilla] (UPO), Laboratoire Motricité Humaine Expertise Sport Santé (LAMHESS), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université de Toulon (UTLN)-Université Côte d'Azur (UCA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Motricité, interaction, performance EA 4334 (MIP), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Université de Toulon (UTLN), Laboratoire Interuniversitaire de Biologie de la Motricité ( LIBM ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Université Jean Monnet [Saint-Étienne] ( UJM ) -Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ), Institut national du sport, de l'expertise et de la performance ( INSEP ), Motricité, interaction, performance ( MIP ), Université de Nantes ( UN ), Centre de Recherche sur le Sport et le Mouvement ( CeRSM ), Université Paris Nanterre ( UPN ), Déterminants Interculturels de la Motricité et de la Performance Sportive ( DIMPS ), Université de la Réunion ( UR ), Universidad Pablo de Olavide, Laboratoire Motricité Humaine Expertise Sport Santé ( LAMHESS ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Université de Toulon ( UTLN ), Université de Lyon-Université de Lyon-Université Jean Monnet - Saint-Étienne (UJM)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), and Université Nice Sophia Antipolis (1965 - 2019) (UNS)

Subjects
[PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph], [ PHYS.MECA.BIOM ] Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph]
Abstract

International audience; This study aimed to validate a simple field method for determining force– and power–velocity relationships and mechanical effectiveness of force application during sprint running. The proposed method, based on an inverse dynamic approach applied to the body center of mass, estimates the step-averaged ground reaction forces in runner's sagittal plane of motion during overground sprint acceleration from only anthropometric and spatio-temporal data. Force– and power–velocity relationships, the associated variables, and mechanical effectiveness were determined (a) on nine sprinters using both the proposed method and force plate measurements and (b) on six other sprinters using the proposed method during several consecutive trials to assess the inter-trial reliability. The low bias (

Published
2015

53. Mesure de l’activité musculaire par électromyographie

Author

Duc, Sebastien, DOREL, Sylvain, Performance, Santé, Métrologie, Société - EA 7507 (PSMS), and Université de Reims Champagne-Ardenne (URCA)

Subjects
[SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2014

54. Mental fatigue alters the speed and the accuracy of the ball in table tennis.

Author

Le Mansec, Yann, Pageaux, Benjamin, Nordez, Antoine, Dorel, Sylvain, and Jubeau, Marc

Subjects
PSYCHOLOGY of athletes, ATHLETIC ability, ELBOW, KINEMATICS, KNEE, MEDICAL protocols, MENTAL fatigue, MUSCLE strength, STATISTICAL sampling, TENNIS, RANDOMIZED controlled trials, MUSCLE fatigue
Abstract

This study aimed at evaluating the effects of mental and muscle fatigue on table tennis performance. Mental fatigue (MF) was induced by completion of 90 minutes of the AX-CPT; muscle fatigue was induced by completion of an eccentric exercise performed with the elbow flexors (biceps fatigue, BF) or the knee extensors (quadriceps fatigue, QF). The control condition consisted of watching a movie. Stroke parameters (speed and accuracy of the ball), as well as feelings of fatigue and force production capacity of the elbow flexors (BF, MF and control conditions) and knee extensors (QF condition), were assessed pre and post fatigue protocols. Feelings of fatigue increased post fatigue protocols. Force production capacity decreased only in the BF and QF conditions. BF and MF induced a decrease in accuracy. This decrease in accuracy was associated with an increased ball speed in the BF condition, and a decreased ball speed in the MF condition. QF had a negligible effect on stroke performance. Our results suggest that both mental fatigue, and muscle fatigue, significantly impair table tennis performance and therefore coaches should take into account both the physical and mental state of table tennis players to optimize performance. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

55. Lower limb muscle activity during table tennis strokes.

Author

Le Mansec, Yann, Dorel, Sylvain, Hug, François, and Jubeau, Marc

Subjects
*LEG physiology, *HAND physiology, *SKELETAL muscle physiology, *GLUTEAL muscles, *ATHLETES, *BIOMECHANICS, *ELECTROMYOGRAPHY, *JUMPING, *MUSCLE contraction, *RACKET games, *HAMSTRING muscle, *QUADRICEPS muscle, *CALF muscles, *BODY movement, *DESCRIPTIVE statistics, *RECTUS femoris muscles, *PHYSIOLOGY
Abstract

This study aimed to compare the muscle activity of lower limbs across typical table tennis strokes. Fourteen high-level players participated in this study in which five typical strokes (backhand top, forehand top, forehand spin, forehand smash, flick) were analysed. Surface electromyography activity (EMG) of eight muscles was recorded (gluteus maximus, biceps femoris, vastus medialis, vastus lateralis, rectus femoris, gastrocnemius medialis, gastrocnemius lateralis, soleus) and normalised to the maximal activity measured during squat jump or isometric maximal voluntary contractions. The forehand spin, the forehand top and the forehand smash exhibited significant higher EMG amplitude when compared with other strokes. Both biceps femoris and gluteus maximus were strongly activated during the smash, forehand spin and forehand top (from 62.8 to 91.7% of maximal EMG activity). Both vastii and rectus femoris were moderately to strongly activated during the forehand spin (from 50.4 to 62.2% of maximal EMG activity) whereas gastrocnemii and soleus exhibited the highest level of activity during the smash (from 67.1 to 92.1% of maximal EMG activity). Our study demonstrates that offensive strokes, such as smash or forehand top, exhibit higher levels of activity than other strokes. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

56. Comparison between ultrafast ultrasound based and alpha methods to assess muscle and tendon stiffness during short range experiments

Author

Hauraix, Hugo, Dorel, Sylvain, Fouré, Alexandre, Cornu, Christophe, Nordez, Antoine, Motricité, interactions, performance EA 4334 / Movement - Interactions - Performance (MIP), Le Mans Université (UM)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université de Nantes (UN)-Université de Nantes (UN), Centre de résonance magnétique biologique et médicale (CRMBM), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Centre National de la Recherche Scientifique (CNRS), and International Society of Electrophysiology and Kinesiology

Subjects
[SDV]Life Sciences [q-bio]
Published
2014

57. Interaction between gastrocnemius medialis fascicle and Achilles tendon compliance: a new insight on the quick-release method

Author

Farcy, Stevy, Nordez, Antoine, DOREL, Sylvain, Hauraix, Hugo, Portero, Pierre, Rabita, Giuseppe, French Institute of Sport (INSEP), Research Department, Laboratory Sport, Expertise and Performance (EA7370) (SEP (EA7370)), Institut national du sport, de l'expertise et de la performance (INSEP), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Motricité, interaction, performance EA 4334 (MIP), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université de Nantes (UN)-Université de Nantes (UN), Motricité, interactions, performance EA 4334 / Movement - Interactions - Performance (MIP), Le Mans Université (UM)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), and Université de Nantes (UN)-Université de Nantes (UN)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Le Mans Université (UM)

Subjects
musculoskeletal diseases, [SHS.SPORT]Humanities and Social Sciences/Sport, Ultrafast, Interactions, Ultrasound, aponeurosis, musculoskeletal system, Compliance
Abstract

International audience; The insufficient temporal resolution of imaging devices has made the analysis of very fast movements, such as those required to measure active muscle-tendon unit stiffness, difficult. Thus the relative contributions of tendon, aponeurosis, and fascicle to muscle-tendon unit compliance remain to be determined. The present study analyzed the dynamic interactions of fascicle, tendon, and aponeurosis in human gastrocnemius medialis during the first milliseconds of an ankle quick-release movement, using high-frame-rate ultrasonography (2,000 frames/s). Nine subjects performed the tests in random order at six levels of maximal voluntary contraction (MVC) (30% to 80% of MVC). These tests were carried out with the ultrasound probe placed on the muscle belly and on the myotendinous junction. Tendon, muscle fascicle, and aponeurosis length changes were quantified in relation to shortening of the muscle-tendon unit during the first few milliseconds following the release. The tendon was the main contributor (around 72%) to the shortening of the muscle-tendon unit, whereas the muscle fascicle and aponeu-rosis contributions were 18% and 10%, respectively. Because these structures can be considered in series, the quantified contributions can be regarded as relative contributions to muscle-tendon compliance. These contributions were not modified with the level of MVC or the time range used for the analysis between 10 and 25 ms. The constant contribution of tendon, muscle fascicle, and aponeurosis to muscle-tendon unit compliance may help to simplify the mechanism of compliance regulation and to maintain the important role of tendons in enhancing work output and movement efficiency.

Published
2014

58. Distribution of power output during the cycling stage of Triathlon World Cup

Author

Bernard, Thierry, Hausswirth, Christophe, Le Meur, Yann, Bignet, Frank, Dorel, Sylvain, and Brisswalter, Jeanick

Subjects
BG Triathlon World Cup -- 2008 AD, Athletes -- Health aspects, Muscle strength -- Measurement, Health, Sports and fitness
Abstract

The power output in the Olympic triathlon's cycle phase is investigated. Findings show a progressive decrease in power output and speed and a rise in variability during the said event. Recommendations for quantifying the intensity of a race are also given.

Published
2009

62. Changes in spring-mass behavior and muscle activity during an exhaustive run at _ VO 2max

Author

Rabita, Giuseppe, Couturier, Antoine, DOREL, Sylvain, Hausswirth, Christophe, Le Meur, Yann, French Institute of Sport (INSEP), Research Department, Laboratory Sport, Expertise and Performance (EA7370) ( SEP (EA7370) ), Institut national du sport, de l'expertise et de la performance ( INSEP ), Motricité, interaction, performance ( MIP ), Université de Nantes ( UN ), French Institute of Sport (INSEP), Research Department, Laboratory Sport, Expertise and Performance (EA7370) (SEP (EA7370)), Institut national du sport, de l'expertise et de la performance (INSEP), Motricité, interaction, performance EA 4334 (MIP), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université de Nantes (UN)-Université de Nantes (UN), Motricité, interactions, performance EA 4334 / Movement - Interactions - Performance (MIP), Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université de Nantes (UN)-Université de Nantes (UN)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Le Mans Université (UM), and Le Mans Université (UM)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS)

Subjects
[ SDV.MHEP.PHY ] Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO], Spring-mass model, [SDV.MHEP.PHY]Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO], [ SHS.SPORT.PS ] Humanities and Social Sciences/Sport/Sport physiology, Force platform, human activities, [ SHS.SPORT ] Humanities and Social Sciences/Sport, Fatigue, Lower limb muscles
Abstract

International audience; Purpose: The aim of this study was to evaluate concomitantly the changes in leg-spring behavior and the associated modifications in the lower limb muscular activity during a constant pace run to exhaustion at severe intensity. Methods: Twelve trained runners performed a running test at the velocity associated with _ VO 2max (5.1 70.3 m s −1 ; mean time to exhaustion: 3537 69 s). Running step spatiotemporal parameters and spring-mass stiffness were calculated from vertical and horizontal components of ground reaction force measured by a 6.60 m long force platform system. The myoelectrical activity was measured by wireless surface electrodes on eight lower limb muscles. Results: The leg stiffness decreased significantly (−8.9%; Po 0.05) while the vertical stiffness did not change along the exhaustive exercise. Peak vertical force (−3.5%; Po 0.001) and aerial time (−9.7%; P o0.001) decreased and contact time significantly increased (+4.6%; Po 0.05). The myoelectrical activity decreased significantly for triceps surae but neither vastus medialis nor vastus lateralis presented significant change. Both rectus and biceps femoris increased in the early phase of swing (+14.7%; P o0.05) and during the pre-activation phase (+16.2%; Po 0.05). Conclusion: The decrease in leg spring-stiffness associated with the decrease in peak vertical ground reaction force was consistent with the decline in plantarflexor activity. The biarticular rectus femoris and biceps femoris seem to play a major role in the mechanical and spatiotemporal adjustments of stride pattern with the occurrence of fatigue during such exhaustive run.

Published
2013

65. Evolution des paramètres électromyographiques et mécaniques au cours d'une épreuve rectangulaire de pédalage menée jusqu'à épuisement

Author

DOREL, Sylvain, Hug, François, Couturier, Antoine, CHAMPOUX, YVAN, DROUET, JEAN-MARC, Hausswirth, Christophe, Vandewalle, Henry, Institut national du sport et de l'éducation physique (INSEP), Université de Sherbrooke (UdeS), and Institut National du Sport et de l'Education Physique (INSEP)

Subjects
[SHS.SPORT]Humanities and Social Sciences/Sport, [SHS.SPORT.PS]Humanities and Social Sciences/Sport/Sport physiology, [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph]
Published
2008

66. Analyse comparée des contraintes énergétiques et musculaires d’un effort maximal réalisé sur le plat et en côte chez des athlètes élites

Author

Hanon, Christine, Slawinski, Jean, DOREL, Sylvain, Hug, François, Couturier, Antoine, MORIN, Jean-Benoît, Institut national du sport et de l'éducation physique (INSEP), Team Lagardère, Centre d’Expertise, Team Lagardère, Motricité, interactions, performance EA 4334 / Movement - Interactions - Performance (MIP), Le Mans Université (UM)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université de Nantes (UN)-Université de Nantes (UN), Université de Saint-Etienne, Institut National du Sport et de l'Education Physique (INSEP), Motricité, interaction, performance EA 4334 (MIP), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), Université de Nantes - UFR des Sciences et Techniques des Activités Physiques et Sportives (UFR STAPS), and Université de Nantes (UN)-Université de Nantes (UN)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Le Mans Université (UM)

Subjects
[SHS.SPORT]Humanities and Social Sciences/Sport, [SHS.SPORT.PS]Humanities and Social Sciences/Sport/Sport physiology, [PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph]
Published
2008

82. Development of Multi-platform Instrumented Force Pedals for Track Cycling (P49).

Author

Drouet, Jean-Marc, Champoux, Yvan, and Dorel, Sylvain

Abstract

The aim of this research was to develop instrumented force pedals that meet the specific requirements of track cycling. Both pedals are instrumented with eight strain gauges and provide the ability to measure normal and tangential pedalling forces. Rotary encoders are used to determine the angular position of the pedals relative to the crank arm and the angular position of the crank arm relative to the bicycle frame. One original feature is that the instrumented pedals can be fitted with interchangeable pedal platforms: the clipless LOOK CX7 and the Shimano 600 (PD-6400) with a toe-dip and strap for sprint and kilometre time trial events. It is therefore possible to measure pedal loads for all track cycling disciplines. The pedals have a very high mechanical resistance in order to withstand the pedal loads produced by track sprinters which are the highest encountered among all cycling disciplines. Their mechanical design allows the pedals to be installed on any crank arm model without requiring any crank modification. With the data acquisition system attached to a modified Camelbak pack carried by the cyclist, the pedals permit on-track pedal load measurements. Post-processing software was developed to calculate derived parameters, which include the effective power, the effectiveness index and two components of the total force: the effective force component that is the component normal to the crank arm and the force component in line with the crank arm. The derived parameter calculations and analysis can be done on site for each leg and allow specific qualities to be evaluated (peak power, peak force, etc.). Typical results for these parameters are presented in this paper. [ABSTRACT FROM AUTHOR]

Published
2008
Full Text
View/download PDF

83. Influence of gender on pacing adopted by elite triathletes during a competition.

Author

Meur, Yann le, Hausswirth, Christophe, Dorel, Sylvain, Bignet, Frank, Brisswalter, Jeanick, Bernard, Thierry, and Le Meur, Yann

Subjects
PHYSICAL fitness testing, AEROBIC exercises, ATHLETES' health, HEART beat, CYCLING, ATHLETIC ability testing, COMPARATIVE studies, EXERCISE, RESEARCH methodology, MEDICAL cooperation, RESEARCH, RUNNING, SEX distribution, SWIMMING, TASK performance, EVALUATION research
Abstract

The aim of this study was to compare the pacing strategies adopted by women and men during a World Cup ITU triathlon. Twelve elite triathletes (6 females, 6 males) competed in a World Cup Olympic distance competition where speed and heart rate (HR) were measured in the three events. The power output (PO) was recorded in cycling to determine the time spent in five intensity zones ([0-10% VT1]; [10% VT1-VT1]; [VT1-VT2]; [VT2-MAP] and > or =MAP) [ventilatory threshold (VT); maximal aerobic power (MAP)]. Swimming and running speeds decreased similarly for both genders (P < 0.05) and HR values were similar through the whole race (92 +/- 2 and 92 +/- 3% of maximal HR for women and men, respectively). The distribution of time spent in the five zones during the cycling leg was the same for both genders. The men's speed and PO decreased after the first bike lap (P < 0.05) and the women spent relatively more time above MAP in the hilly sections (45 +/- 4 vs. 32 +/- 4%). The men's running speed decreased significantly over the whole circuit, whereas the women slowed only over the uphill and downhill sections (P < 0.05). This study indicates that both female and male elite triathletes adopted similar positive pacing strategies during swimming and running legs. Men pushed the pace harder during the swim-to-cycle transition contrary to the women and female triathletes were more affected by changes in slope during the cycling and running phases. [ABSTRACT FROM AUTHOR]

Published
2009
Full Text
View/download PDF

84. Changes in spring-mass behavior and muscle activity during an exhaustive run at VO2max.

Author

Rabita, Giuseppe, Couturier, Antoine, Dorel, Sylvain, Hausswirth, Christophe, and Meur, Yann Le

Subjects
*COLLECTIVE behavior, *MUSCLE physiology, *RUNNERS (Sports) physiology, *FATIGUE (Physiology), *SPATIOTEMPORAL processes, *PARAMETER estimation, *ELECTROMYOGRAPHY
Abstract

Purpose: The aim of this study was to evaluate concomitantly the changes in leg-spring behavior and the associated modifications in the lower limb muscular activity during a constant pace run to exhaustion at severe intensity. Methods: Twelve trained runners performed a running test at the velocity associated with VO2max (5.1±0.3ms-1; mean time to exhaustion: 353±69s). Running step spatiotemporal parameters and spring-mass stiffness were calculated from vertical and horizontal components of ground reaction force measured by a 6.60m long force platform system. The myoelectrical activity was measured by wireless surface electrodes on eight lower limb muscles Results: The leg stiffness decreased significantly (-8.9%; P<0.05) while the vertical stiffness did not change along the exhaustive exercise. Peak vertical force (-3.5%; P<0.001) and aerial time (-9.7%; P<0.001) decreased and contact time significantly increased (+4.6%; P<0.05). The myoelectrical activity decreased significantly for triceps surae but neither vastus medialis nor vastus lateralis presented significant change. Both rectus and biceps femoris increased in the early phase of swing (+14.7%; P<0.05) and during the pre-activation phase (+16.2%; P<0.05). Conclusion: The decrease in leg spring-stiffness associated with the decrease in peak vertical ground reaction force was consistent with the decline in plantarflexor activity. The biarticular rectus femoris and biceps femoris seem to play a major role in the mechanical and spatiotemporal adjustments of stride pattern with the occurrence of fatigue during such exhaustive run. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
View/download PDF

85. Interaction between gastrocnemius medialis fascicle and Achilles tendon compliance: a new insight on the quick-release method.

Author

Farcy S, Nordez A, Dorel S, Hauraix H, Portero P, and Rabita G

Subjects
Achilles Tendon diagnostic imaging, Adolescent, Adult, Compliance physiology, Humans, Male, Muscle, Skeletal diagnostic imaging, Time Factors, Ultrasonography, Young Adult, Achilles Tendon physiology, Ergometry methods, Isometric Contraction physiology, Muscle, Skeletal physiology
Abstract

The insufficient temporal resolution of imaging devices has made the analysis of very fast movements, such as those required to measure active muscle-tendon unit stiffness, difficult. Thus the relative contributions of tendon, aponeurosis, and fascicle to muscle-tendon unit compliance remain to be determined. The present study analyzed the dynamic interactions of fascicle, tendon, and aponeurosis in human gastrocnemius medialis during the first milliseconds of an ankle quick-release movement, using high-frame-rate ultrasonography (2,000 frames/s). Nine subjects performed the tests in random order at six levels of maximal voluntary contraction (MVC) (30% to 80% of MVC). These tests were carried out with the ultrasound probe placed on the muscle belly and on the myotendinous junction. Tendon, muscle fascicle, and aponeurosis length changes were quantified in relation to shortening of the muscle-tendon unit during the first few milliseconds following the release. The tendon was the main contributor (around 72%) to the shortening of the muscle-tendon unit, whereas the muscle fascicle and aponeurosis contributions were 18% and 10%, respectively. Because these structures can be considered in series, the quantified contributions can be regarded as relative contributions to muscle-tendon compliance. These contributions were not modified with the level of MVC or the time range used for the analysis between 10 and 25 ms. The constant contribution of tendon, muscle fascicle, and aponeurosis to muscle-tendon unit compliance may help to simplify the mechanism of compliance regulation and to maintain the important role of tendons in enhancing work output and movement efficiency.

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results