OpenCap and OpenSim for the 3D Kinematic Analysis of Load Handling Tasks Performed in Construction

Construction tasks are associated with high physical demands. However, biomechanical risk analysis often relies on direct observation or videography due to the high costs of 3D technology and the challenges of field assessment. The development of open-source, marker less 3D motion capture technology offers new opportunities for more objective evaluations of work tasks, which are currently under-researched. This study aimed to assess the potential of Open Cap and OpenSim for conducting biomechanical evaluations in the field. Methodology: A descriptive study with a qualitative-quantitative approach was conducted, evaluating the 3D kinematics of the trunk in ten subjects performing tasks such as shoveling, lifting, and throwing bricks, and lifting 25 kg bags at a construction site. Qualitative validation of the technology used was also performed. Data were collected using three iOS mobile phones, filming at 60 fps with the OpenCap application, and processed in the cloud. Kinematic data were exported to the OpenSim LaiUlrich2022 model, and analyses of range of motion, standard deviations, and coefficients of variation among subjects were conducted. Results: All three tasks showed simultaneous trunk movements across three planes, increasing occupational risk. High variability in execution was seen among participants (CV 0.12 - 1.48). Direct export to OpenSim complemented kinematic analysis, but adequate kinetic analysis requires external load information, which was not included in this study. Conclusions: Despite some limitations, Open Cap and OpenSim provide a cost-effective means to objectively assess biomechanical risk in work activities.