Document Detail


Changes in spring-mass behavior and muscle activity during an exhaustive run at V̇O2max.
MedLine Citation:
PMID:  23850446     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
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 V̇O2max (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.
Authors:
Giuseppe Rabita; Antoine Couturier; Sylvain Dorel; Christophe Hausswirth; Yann Le Meur
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Publication Detail:
Type:  Journal Article     Date:  2013-07-11
Journal Detail:
Title:  Journal of biomechanics     Volume:  46     ISSN:  1873-2380     ISO Abbreviation:  J Biomech     Publication Date:  2013 Aug 
Date Detail:
Created Date:  2013-07-29     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0157375     Medline TA:  J Biomech     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2011-7     Citation Subset:  IM    
Copyright Information:
Copyright © 2013 Elsevier Ltd. All rights reserved.
Affiliation:
Research Department, National Institute of Sport, Expertise and Performance, INSEP, Paris, France. Electronic address: giuseppe.rabita@insep.fr.
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