Effect of a back-support exoskeleton on internal forces and lumbar spine stability during low load lifting task

This study assessed the effect of a small-torque generating passive back-support exoskeleton during a low demanding occupational task, namely a repetitive lifting/lowering of an empty crate between the knee and shoulder heights. A comprehensive set of outcomes was considered, ranging from the measured trunk muscle activation and trunk movement to the estimated muscle group forces/coordination, spine loading and spine stability, using a dynamic subject-specific EMG-assisted musculoskeletal model. The exoskeleton decreased back muscle activation and corresponding muscle forces in the lowering phase and reduced spinal loading at larger trunk flexion angles (decreased peak compression and shear forces by ∼ 15%). However, the effect sizes were small (η