The construction manufacturing industry in North America has a disproportionately high number of lost-time injuries due to the high physical demand of the labour-intensive tasks it involves. It is essential to investigate the physical demands of body movement in the construction manufacturing workplace in order to proactively identify worker exposure to ergonomic risk. This research thus analyzes the primary ergonomic risk factors that cause work-related injuries:​ awkward body posture, overexertion, and repetitive motion.

This research first develops a framework to approach an improved physical demand analysis for risk identification, evaluation, and mitigation by providing modified work. The framework is implemented in a manufacturing industry facility, and four main ergonomic risk identifications, together with the corresponding modified work, are recommended. Second, a framework of assessing muscle force and muscle fatigue development due to manual repetitive lifting tasks using surface electromyography (sEMG), kinematic motion capture, and human body modelling is also proposed. The results show that sEMG is capable of visualizing muscle activity. However, it is limited to identifying muscle fatigue development of bulkier and superficial muscle bundles in low fat areas. Physiological measurements also have technical, ethical, cost, and real-life implementation limitations. This research thus further investigates an innovative framework for converting observational or video-captured body movements in an actual construction manufacturing plant into 3D modelling for ergonomic risk assessment of continuous motions. The proposed 3D motion-based risk assessment methodology is validated through the aforementioned motion capture experiment to prove the reliability of the framework. The integration between the first and third framework is also proposed and implemented in modular construction operations. Thus the capability of 3D modelling is extended to support the optimization of human body movement and the re-design of the workplace accordingly to mitigate the ergonomic risks inherent in operational tasks. Modified work recommendations are expected as a result of this research, which facilitates the establishment of a more robust returnto-work program for various industries. Ultimately, the goal is to proactively curtail workplace injuries and claims and thereby reduce workers’ compensation insurance costs.