Development of a fatigue-tracking system for monitoring human body movement

Monitoring fatigue and furthermore predicting fatigue is quite important in fundamental research and practical applications. In this paper, we developed a wireless wearable system for quantifying and tracking fatigue. The system is based on the scientific electromyography kinesiology study, which shows the mean frequency of the surface electromyogram (sEMG) signal decreases with the increase of fatigue intensity. According to this clue, from the engineering viewpoint, we assume the decrease relation mentioned is a linear relation and use statistical analysis (including 10 male subjects and 7 female subjects) to prove this assumption. Besides, in order to accurately assess fatigue, fatigue level is defined. Based on the simplified linear model mentioned, the fatigue level can be calculated efficiently. Furthermore, by considering the fatigue process as a dynamic process, we track the fatigue level by “forgetting” the sEMG measurement history taken at a relatively long time ago. Finally, the performance of the developed fatigue tracking system is tested and verified by the experiment of holding self weight.