Evaluation of Lumbar Loads and Neuromuscular Responses with an Occupational Soft-Back Exoskeleton During a Repetitive Sagittal Handling Task

Back-support exoskeletons have emerged as promising ergonomic interventions to assist workers during repetitive manual handling tasks, particularly when task redesign or automation is not feasible. However, limited research has examined the evolution of lumbar biomechanical parameters throughout the task. This study aimed to evaluate the effects of the CORFOR® soft-back exoskeleton on lumbar loads at L5-S1, muscle activity, and perceived exertion during a repetitive sagittal-plane manual handling task in eleven young shealthy male participants over a 4-min protocol. Results showed a significant increase in perceived lower back exertion over time. However, no significant difference in perceived exertion was found between EXO and FREE conditions despite reductions of 11–13%. Lumbar loads at L5-S1 were significantly reduced when using the soft-back exoskeleton in both lowering and lifting phases (−14% for peak flexion–extension moment, −6% for compression force, and −10% for shear force). In addition, peak flexion–extension moment and peak compression force significantly decreased over time. Significant interactions between exoskeleton use and time were observed for peak L5-S1 flexion–extension moment and right ES muscle activity. Overall, these findings partially support our hypothesis, as the CORFOR® reduced lumbar mechanical demands ES muscle activity, with some additional time-dependent effects observed.