Influence of an Exoskeleton on Inter and Intra Task Cycle Variations in Muscle Demands During Intermittent Bending

Temporal effects of exoskeletons can be effectively understood through assessments that incorporate realistic conditions, while using accurate instrumentation in controlled settings. We tracked variations in back and leg muscle activity as twelve participants performed intermittent task cycles involving symmetric and asymmetric bending with a Back-Support Industrial Exoskeleton (BSIE). Comparative assessments were conducted within and across multiple task cycles with fatigue progression. BSIE offered benefits in reducing back demands (9-22%) during bending portion. However, the device increased activity during retraction (80-11%). During sustained bending, asymmetry reduced BSIE benefits in right back region (13% vs. 22% in symmetric postures) and larger benefits of 11-15% were seen in back muscles at low vs. medium fatigue levels. Recommendations indicate having a ratio of dynamic: sustained activities < 30:1 to ensure benefits of BSIEs in back. Overall, outcomes can be helpful for understanding temporal benefits of BSIEs for trunk bending tasks.