Titre
Twitch potentiation is greater after a fatiguing submaximal isometric contraction performed at short vs. long quadriceps muscle length.
Type
article
Institution
Externe
Périodique
Auteur(s)
Place, N.
Auteure/Auteur
Maffiuletti, N.A.
Auteure/Auteur
Ballay, Y.
Auteure/Auteur
Lepers, R.
Auteure/Auteur
Liens vers les personnes
ISSN
8750-7587
Statut éditorial
Publié
Date de publication
2005
Volume
98
Numéro
2
Première page
429
Dernière page/numéro d’article
436
Langue
anglais
Résumé
Endurance time of a submaximal sustained contraction is longer when the muscle is fatigued in a shortened position. The aim of the present study was to compare central and peripheral mechanisms of fatigue after an isometric contraction of the knee extensor muscles performed at 20% maximal voluntary contraction (MVC) at two knee angles (35 degrees , short length vs. 75 degrees , long length; 0 degrees = full extension) until exhaustion. Eleven men (24 +/- 4 yr) attended two experimental randomized sessions. Endurance time was greater at 35 degrees compared with 75 degrees (974 +/- 457 vs. 398 +/- 144 s; P < 0.001) despite a similar reduction in knee extensor MVC (-28.4 +/- 16.0%, P < 0.001 vs. -27.6 +/- 18.8%, P < 0.001, respectively). Voluntary activation level was similarly depressed after the fatiguing contraction performed at the two muscle lengths (-19 +/- 16.7% at 35 degrees , P < 0.01 vs. -13.7 +/- 14.5% at 75 degrees , P < 0.01). After the fatiguing contraction, peak twitch potentiation was observed only at the short length (+31.8 +/- 17.6% at 35 degrees , P < 0.01 vs. +6.4 +/- 21.3% at 75 degrees , P > 0.05), whereas M-wave properties were similarly altered for the two angles. These results suggest that 1) central fatigue at task failure for a sustained isometric contraction was not dependent on the muscle length, and 2) the longer endurance time of a sustained isometric contraction performed at a shortened length is related to potentiation. It is suggested that the greater endurance time of a sustained isometric contraction observed at 35 degrees is related to the occurrence of potentiation at this short length, because central fatigue is similar at task failure for both tasks.
PID Serval
serval:BIB_BCA42626F22A
PMID
Date de création
2013-09-19T07:51:19.047Z
Date de création dans IRIS
2025-05-20T21:13:45Z