MEASUREMENT OF SHORT-TERM LOCAL MUSCLE FATIGUE BY USING EMG FREQUENCY ATTRIBUTES

Abstract

We attempted to find parameters that can sensitively assess the short-term muscle fatigue. In this study we separated EMG signals into low (15-45 Hz), medium (46-95 Hz) and high (˃95 Hz) frequency band and to investigate the parameters including median power frequency (MPF), [Medium/Low] frequency band ratio, and High/[Medium+Low] frequency band ratio, because the frequency change is the main phenomenon in muscle fatigue. The deltoid muscle which is sensitive to shoulder fatigue was selected from 10 participants and EMG was measured at 30%, 40%, and 50% MVC when the shoulder flexion was at 90 degrees. As a result of the analysis MPF and High/[Low+Medium] parameters decreased as the time passed at all MVC conditions. [Medium/Low] under 50% MVC condition. The parameters tested in this study can be further applied to examine efficacy of detecting the low level or short-term muscle fatigue in various muscles and experimental conditions.