Passive Back-Support Exoskeletons Reduce Cumulative Spinal Loading During Aeronautical Tasks

Effects of passive back-support exoskeletons (BSEs) on internal spinal loading during aeronautical tasks remain unclear. We quantified changes in L5/S1 compression force while 19 male participants performed representative aeronautical polishing and handling tasks (sustained flexed inspection, simulated polishing, and asymmetric load transfers) under three BSE conditions: no BSE control, BackX and Laevo FLEX. Whole-body kinematics were measured with wearable inertial sensors, and peak and time-averaged compression forces were estimated using musculoskeletal modeling. During inspection and polishing tasks, both BackX and Laevo reduced time-averaged compression by 14% and 6%, respectively, indicating decreased cumulative spinal loading during sustained trunk flexion. During asymmetric transfers, Laevo showed greater benefits, reducing time-averaged compression by 17% during lifting and reducing peak and time-averaged compression by 13% and 26%, respectively, during lowering. Overall, passive BSEs primarily reduced cumulative rather than peak spinal loading, supporting their selective use for aeronautical tasks involving sustained trunk flexion and asymmetric handling.