Development and EMG/metabolic assessment of a passive shoulder exoskeleton providing adjustable support for high arm elevation.

Exoskeletons are increasingly used to reduce physical strain during overhead and repetitive manual tasks. This study evaluated a novel passive upper limb exoskeleton adjustable for maximum support at different arm elevation angles. Ten male participants performed repetitive arm movements with a 2.5 kg weight along a sinusoidal trajectory at elevations between 90° and 135° in the sagittal plane. Use of the exoskeleton resulted in a statistically significant (p < 0.05) reduction in muscle activity in the anterior deltoid and biceps brachii. Muscle activity for the lower trapezius, latissimus dorsi, erector spinae, and pectoralis major showed numerical reductions, but these were not statistically significant (p > 0.05). With exoskeleton use, reductions were observed in heart rate, [Formula: see text] , [Formula: see text] and RER, although only changes in [Formula: see text] and RER were statistically significant. Respiratory frequency did not decrease (p > 0.05). Future research should include a more diverse participant group, tasks that better represent real-world manual labour, and direct comparisons with already established exoskeletons.