Simulation-based biomechanical assessment of a passive back support exoskeleton: Comparison of various support levels during a sustained forward bending task

This study evaluated the impacts of five support levels (40, 55, 70, 85, and 100 % actuator strengths) of a passive back-support exoskeleton (BSE) on biomechanical loads associated with commercial crab sorting through musculoskeletal simulation. Whole-body kinematics of 20 male participants performing simulated crab sorting were collected and integrated into a human-BSE interaction simulation framework to predict muscle activity, spinal loads, and contact forces at the human-BSE interfaces. Increasing the BSE support level generally reduced trunk extensor muscle activity (up to 28.6 %) and lumbosacral reaction forces (up to 30.7 %). However, the reduced biomechanical load came at the expense of increased contact forces on the chest and thigh areas, potentially causing local discomfort for vulnerable users. These findings suggest that while BSEs can be effective in reducing low back biomechanical loads during crab sorting, support levels should be carefully selected to ensure adequate assistance while minimizing potential side effects, such as local discomfort or pain.