Lossless measurement and evaluation for predicting the rating of perceived physical fatigue

There is a muscle force failure caused by physical fatigue. Since the change in myoelectrical activity occurs in advance of the failure, surface EMG (SEMG) is valuable. However, the accuracy of SEMG manifestation is not always guaranteed spatiotemporally. We first introduced a 2D surface electrode to search the location of electrode on the skin where SEMG manifestations are fully detected with high accuracy. Furthermore, enough precision is important to interpret the physiological activities. Then we determine the motion related target muscles, adopting the idea of muscle synergy. That is, based on the fact that functional activities are stemmed from a hierarchical multi-timescale system, we model a rating of perceived physical fatigue (RPF) integrating the psychological manifestation (long-term event) by physiological one (short-term event). This will lead to lossless measurement and evaluation for a faster prediction of the physical fatigue induced failure. The ultimate goal is a ubiquitous strategy for risk avoidance by establishing the RPF for safely controlling the electrical power assist.