Application of Paper-Based Wearable Electronics (PBWE) for Objective Assessment of Fatigue in Lower Back of Construction Workers

Wearable sensors proposed to measure fatigue in construction have shortcomings such as cumbersome size, high cost, flexibility, and high noise-to-amplitude ratio. Hence, this article demonstrates the use of inexpensive paper-based wearable electronics (PBWE) for predicting fatigue in the lower back of construction workers without compromising skin breathability or the natural motions of the wearer and with a low noise-to-amplitude ratio. Five subjects were recruited to participate in a simulated manual lifting activity in the form of a repetitive lifting task while measuring their physiological conditions using paper-based wearable electronics, EMG, and off-the-shelf optical heart rate monitors. Analysis of variance (ANOVA) was employed for this study. The BORG scale was also used to assess the fatigue level of the participants subjectively. The noise-to-amplitude ratio of the paper-based wearable electronics (PBWE) was significantly lower than that of the EMG by about 4.5 times. The analysis produced p-values less than 0.05, implying a significant change in the fatigue level after carrying out the repetitive lifting task from the base value. The findings imply that paper-based wearable electronics are portable and reliable devices that can predict physical fatigue and have excellent potential to improve the safety of construction workers on a construction site.