Alwasel, Abdullatif1; Ryu, Juhyeong2; Abdel-Rahman, Eihab3 and Haas, Carl4

1 Ph.D., Department of Systems Design Engineering, University of Waterloo, 200 University Ave W., Waterloo, ON, Canada,
2 Ph.D. Student, Department of Civil and Environmental Engineering, University of Waterloo,
3 Associate Professor, Department of Systems Design Engineering, University of Waterloo,
4 Professor, Department of Civil and Environmental Engineering, University of Waterloo,

An aging workforce and work related injuries are reducing the number of experienced workers in construction. The decrease in the number of workers is accompanied by increased musculoskeletal disorder (MSD) injury rates and insurance premiums for employers. Adoption of interventions to reduce the number of these injuries has had limited success. These interventions usually apply the same technique to all employees irrespective of their experience level. They have not significantly changed the extent of MSD injuries. Statistics show that the majority of injuries in construction happen to workers while in their training phase, those with less than five years of experience with the same employer. The presented work focuses on investigating whether and in what ways workers’ experience plays a role in safety, productivity, and efficiency. Twenty-one workers were recruited at four experience levels ranging from novices to journeymen with more than five years of experience. Participants were asked to build a 12 x 6 block wall using standard Concrete Masonry Units (CMU). Body kinematics were collected using 17 Inertial Measurement Units (IMUs) attached to major body segments. Video cameras were setup to record workers’ motion from three different positions. Biomechanical analysis was carried out to calculate the forces and moments in major body joints. It shows that low back moment and force levels increase with experience in the first three years with a peak at three years of experience, beyond which they decrease significantly. Moreover, productivity increases with experience, this increase is accompanied with reduced injury rates. These trends suggest that apprentices focus on productivity and efficiency at the cost of health and safety. Hence, they sustain injuries early in their careers. Further analysis will extract expert motion patterns in order to teach them to trainees to enhance the overall training process, improve health and safety, and increase productivity.


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