Continuous Measurement of Muscle Fatigue Using Wearable Sensors During Light Manual Operations.

Optimization of the temporal aspects of task design requires a better understanding of the development of muscle fatigue over time. The study was aimed to use wearable devices to continuously investigate muscle fatigue in the right forearm of 12 assembly workers. Indicators of fatigue were obtained through surface electromyography (sEMG) and ratings of perceived discomfort during daylong assembly tasks. Average EMG amplitude increased over the work day while median frequency decreased. Local perceived fatigue in the shoulder, upper arm, forearm and wrist increased over the course of the day. However, no clear relationship between perceived fatigue and objective indicators of fatigue was found. Using the wearable monitoring sensors, it is promising to improve worker-supervisor fatigue management in real time. This study might further help in the definition and justification of temporal interventions such as changing the length of the working day, adding extra pauses or task variation across time.