Jerk as an indicator of physical exertion and fatigue

摘要

Physical exertion may result in fatigue which is a key factor leading to increased risk of injury, reduced productivity, and decline in work quality in construction. Most practical fatigue assessments rely on subjective measurement scales including surveys and questionnaires. While they have the advantage of being inexpensive to implement, they lack reliability. Objective assessments of physical exertion and fatigue that are based on physiological processes are more reliable, however they are cumbersome to implement on-site. The advent of low-cost, wearable motion sensors has made high-frequency sampling of kinematic data possible. The objective of this study was to assess the feasibility of using jerk, the time derivative of acceleration, as an indicator of physical exertion as fatigue develops over the course of a demanding task. As a proof-of-concept, the method was first tested on participants completing a repetitive physically demanding exercise. The method was then demonstrated in a study of masonry work done by bricklayers with varying levels of masonry experience. We conclude that jerk is a useful indicator of physical exertion and experience level.