등장성 운동 시 회귀부석기간에 따른 근전도 중앙주파수 휘귀직선의 특징

Abstract

Many studies have shown that the initial median frequency (MDF) and slopecorrelate with the muscle fiber composition. This study tested the hypothesis that theinitial MDF and slope are fixed, regardless of the interval at which data are collected. MDF data using moving fast Fourier transformation of EMG signals, following localfatigue induced by isotonic exercise, were obtained. An inverse FFT was used toeliminate noise, and characteristic decreasing regression lines were obtained. Theregression analyses was done in three different periods, the first one third, first half,and full period, looking at variance in the initial MDF, slope, and fatigue index. Datafrom surface EMG signals during fatiguing isotonic exercise of the biceps brachii andvastus lateralis in 20 normal subjects were collected. The loads teated were 30% and60% maximum voluntary contraction (MVC) in the biceps beachlii and 40% and 80%MVC in the vastus lateralis. the rate was 25 flexions per minute. there were nosignificant differences in the initial MDF or slope during the early or full periods of theregeression, but there was a significant difference in the fatigue index. Therefore, toobserve the change in the initial MDF and slope of the MDF regression line duringisotonic exercise, this study suggest that only the early interval need to be observed.