A comparison of assessment methods for muscle fatigue in muscle fatigue contraction

Abstract

Muscle fatigue often occurs in daily life and work. The assessment method of muscle fatigue based on the surface electromyography (sEMG) has been well reported in some comprehensive reviews. Recently, the time domain parameters, frequency domain parameters, discrete wavelet transform and non-linear methods have been widely used for the evaluation of muscle fatigue. In this paper, one fatigue indice was proposed: Area ratio modified index (ARMI) was compared to seven assessment indices: root mean square (RMS), integrated electromyography (IEMG), mean power frequency (MPF), median frequency (MF), wavelet energy (WE), wavelet entropy (WEn) and Lemple–Ziv complexity (LZC). Ten healthy participants completed a fatigue experiment with isometric contraction of biceps brachii. It was showed that there was a significant positive rate of change of RMS, IEMG, WE and ARMI of sEMG, while a negative rate of change of MPF, MF and LZC of sEMG when fatigue occurred, and WEn of sEMG basically had no change. Meanwhile, the percentage deviation in ARMI was greater than the other seven indexes. It was proved that ARMI can be used as effective indicator and was more sensitive than the other seven indexes to evaluate the muscle fatigue.