Mechanisms of fatigue and task failure induced by sustained submaximal contractions.

Détails

ID Serval
serval:BIB_C85D4D46230D
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Mechanisms of fatigue and task failure induced by sustained submaximal contractions.
Périodique
Medicine and Science in Sports and Exercise
Auteur(s)
Neyroud D., Maffiuletti N.A., Kayser B., Place N.
ISSN
1530-0315 (Electronic)
ISSN-L
0195-9131
Statut éditorial
Publié
Date de publication
2012
Volume
44
Numéro
7
Pages
1243-1251
Langue
anglais
Notes
Erratum inMed Sci Sports Exerc. 2012 Sep;44(9):1826.
Résumé
PURPOSE: The present study was designed to investigate whether central neural mechanisms limit the duration of a sustained low-force isometric contraction and the maximal force-generating capacity of the knee extensors.
METHODS: Fourteen healthy males (28 ± 7 yr) were asked to sustain, until voluntary exhaustion, an isometric contraction with their right knee extensor muscles at a target force equal to 20% of their maximal voluntary contraction (MVC) force. At task failure, the muscle was immediately electrically stimulated for 1 min aiming the same target force (20% MVC force). Subsequently, subjects were asked to resume the voluntary contraction for as long as possible. Knee extensor neuromuscular function was assessed before and after the entire protocol for comparison.
RESULTS: When electrically stimulated at the point of task failure, all subjects developed the 20% MVC force target, indicating that lack of force-generating capacity from peripheral impairment had not limited the duration of the first task. We observed a reduction in MVC force after the entire protocol (-57% ± 12%), which correlated with a decrease in potentiated peak doublet force (-48% ± 17%, P < 0.001). The level of voluntary activation, as quantified with the interpolated twitch technique, was slightly depressed after the entire protocol (from 93% ± 7% to 87% ± 10%, P < 0.01).
CONCLUSIONS: It follows that task failure from a sustained isometric contraction is mainly affected by central/motivational factors, whereas MVC force loss is largely explained by the extent of contractile failure of the muscle.
Mots-clé
Adult, Electric Stimulation/methods, Electromyography, Evoked Potentials/physiology, Humans, Isometric Contraction/physiology, Knee, Male, Muscle Fatigue/physiology, Muscle, Skeletal/physiology, Switzerland, Young Adult
Pubmed
Web of science
Création de la notice
19/09/2013 9:30
Dernière modification de la notice
03/03/2018 21:21
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