Original articles  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2002 September;42(3):289-94

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Effects of lower limbs muscular fatigue on anticipatory postural adjustments during arm motions in humans

Vuillerme N., Nougier V., Teasdale N.

From the Laboratoire Sport et Performance Motrice Université Joseph Fourier-Grenoble 1 Grenoble, France *Laboratoire de Performance Motrice Humaine Université Laval, Québec, Canada

Back­ground. The pur­pose of the ­present experi­ment was to exam­ine the ­effects of low­er ­limbs mus­cu­lar ­fatigue on the antic­i­pa­to­ry pos­tu­ral adjust­ments dur­ing a vol­un­tary arm rais­ing move­ment.
Meth­ods. ­Eight ­adult ­males (­mean age 29±6 ­years) vol­un­tar­i­ly par­tic­i­pat­ed to the experi­ment. ­Subjects’ ­task con­sist­ed in per­form­ing an uni­lat­er­al ­ante-flex­ion of the ­right arm ­over 90 deg, hold­ing a 500 g ­weight, ­once hav­ing sta­bi­lized ­their ­upright pos­ture. A sim­i­lar move­ment exe­cu­tion was ­required. Meas­ure­ments ­were ­made in a no-­fatigue sit­u­a­tion and ­under a ­high lev­el of ­fatigue of low­er ­limbs. Sur­face EMG of ­four pos­tu­ral mus­cles (the ipsi­lat­er­al and con­tra­lat­er­al Gas­troc­ne­mi­us and the ipsi­lat­er­al and con­tra­lat­er­al Sem­i­ten­di­no­sus) and of one mus­cle ­involved in the arm rais­ing (the Ante­ri­or ­Deltoïdeus of the ­right arm) was record­ed. ­Body ­sway was ­also mon­i­tored ­using a ­force plat­form.
­Results. ­With ­fatigue, quan­ti­ta­tive EMG anal­y­sis ­showed a ­decrease of the ipsi­lat­er­al Sem­i­ten­di­no­sus activ­ity where­as the tem­po­ral EMG anal­y­sis ­showed an ­increase of its laten­cy ­with ­respect to move­ment ­onset.
Con­clu­sions. ­These ­data sug­gest­ed a func­tion­al adap­ta­tion result­ing in an invar­i­ance of glo­bal antic­i­pa­to­ry pos­tu­ral adjust­ments for the two con­di­tions of no-­fatigue and ­fatigue and ensur­ing an ade­quate exe­cu­tion of the move­ment.