Changes in spring-mass behavior and muscle activity during an exhaustive run at V̇O2max.

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