The effects of body asymmetry in load handling with a back supporting exoskeleton on lumbar loading

This study investigated the effects of a passive back support exoskeleton (BSE) on lumbar loading during lifting tasks involving varying levels of asymmetry. Twelve healthy participants completed lifting tasks with different levels of asymmetry (90°, 135°, 180°) with and without the exoskeleton. The exoskeleton's influence on 3D L5/S1 moments and pelvis orientation was assessed. Results demonstrated that the BSE effectively reduced L5/S1 extension moments (5–11 %), regardless of the level of asymmetry. Frontal and transversal plane moments were not directly influenced by the exoskeleton support, but instead reduced due to changes in task execution. This included orienting the pelvis more towards the lifting direction, especially with increasing task asymmetry. The findings suggest that the tested BSE can provide meaningful support during asymmetric tasks, along its one actuated degree of freedom. Adaptations in task execution should be considered when evaluating their feasibility for real-world use. Further research is recommended to validate these effects under field conditions and in combination with user acceptance. • Regardless of the asymmetry the exoskeleton reduced sagittal plane lumbar loading. • Frontal and transversal plane loading were reduced, but not affected by the support. • The task execution (orientation of the pelvis) was altered by the exoskeleton. • Kinematic changes indirectly reduced lumbar loading with the exoskeleton.