Article

The aim of the present study was to compare spatial electromyographic (EMG)
potential distribution during force production between elderly and young
individuals using multi-channel surface EMG (SEMG).
Thirteen elderly (72-79years)
and 13 young (21-27years) healthy male volunteers performed ramp submaximal
contraction during isometric knee extension from 0% to 65% of maximal voluntary
contraction. During contraction, multi-channel EMG was recorded from the vastus
lateralis muscle. To evaluate alteration in heterogeneity and pattern in spatial
EMG potential distribution, coefficient of variation (CoV), modified entropy and
correlation coefficients with initial torque level were calculated from
multi-channel SEMG at 5% force increment. Increase in CoV and decrease in
modified entropy of RMS with increase of exerted torque were significantly
smaller in elderly group (p<0.05) and correlation coefficients with initial
torque level were significantly higher in elderly group than in young group at
moderate torque levels (p<0.05). These data suggest that the increase of
heterogeneity and the change in the activation pattern are smaller in elderly
individuals than in young individuals. We speculated that multi-channel SEMG
pattern in elderly individual reflects neuromuscular activation strategy
regulated predominantly by clustering of similar type of muscle fibers in aged muscle.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS