Changes in spring-mass behavior and muscle activity during an exhaustive run at V̇O2max
Autor: | Christophe Hausswirth, Giuseppe Rabita, Sylvain Dorel, Yann Le Meur, Antoine Couturier |
---|---|
Rok vydání: | 2013 |
Předmět: |
medicine.medical_specialty
Vastus medialis Chemistry Rehabilitation Biomedical Engineering Biophysics STRIDE 030229 sport sciences Anatomy Biceps Intensity (physics) 03 medical and health sciences 0302 clinical medicine Internal medicine Cardiology medicine Orthopedics and Sports Medicine Force platform Ground reaction force Muscle activity Early phase human activities 030217 neurology & neurosurgery |
Zdroj: | Journal of Biomechanics. 46:2011-2017 |
ISSN: | 0021-9290 |
Popis: | 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. |
Databáze: | OpenAIRE |
Externí odkaz: |