Time-frequency EMG features comparison of biceps brachii and erector spinae in evaluating work level categories of RTW patients

Abstract

Electromyography (EMG) is one of the special tool in assessing human muscle performance. The muscle performance can be evaluated when there exist changes on both the amplitude and frequency simultaneously. However, various time-frequency EMG signal features from literature do not provide easy and direct interpretation of the muscle condition specifically for non-researchers in rehabilitation centers. This study investigates EMG behavior of biceps brachii and erector spinae based on new time-frequency EMG features during functional capacity evaluation (FCE)'s core-lifting task in evaluating work level categories of return to work patients. Surface EMG signals are filtered using band pass filter with cut-off frequency at 5-500 Hz and auto-segmented using spectrogram, while S-transform is used for the features extraction. Result shows that the differences of the proposed EMG features values are significant in indexing muscle performance and are good indicators for the determination of work level categories.