Exoskeletons in Intermittent Bending Tasks: Assessing Muscle Demands,Endurance,and User Perspectives

Abstract

Objective

We investigated effects of a Back-support industrial exoskeleton (BSIE) across intermittently performed unloaded trunk bending task cycles.

Background

Industrial tasks are often performed in the form of task cycles with varying activities and rest breaks after each task cycle. Investigating the effects of BSIEs during such intermittent tasks is crucial to understand translation of their benefits in real-world environments.

Method

Twelve participants performed ∼709 task cycles (sustained bending, bending and retraction, standing still, and relaxation activities) with/without BSIE (E/NE) and with/without 45° asymmetry (S/A) towards left until fatigue. Evaluated measures included muscle activity in left (LES)/right (RES) erector spinae and left (LBF)/right (RBF) biceps femoris muscles, endurance, and user perspectives. Temporal effects of fatigue were examined by categorizing muscle activity based on perceived exertion level with Borg scale.

Results

BSIE reduced low-back (LES, RES), and leg (LBF, RBF) mean amplitude by ∼ 18–24% and ∼10–17% respectively. Benefits of BSIE in low-back reduced by ∼11–15% at medium versus low fatigue. Overall, BSIE led to 50% more completed task cycles and was favorably rated by participants in reducing physical demands, most especially during sustained bending portion of the task cycles.

Conclusion

Using BSIE in intermittent bending tasks can not only provide benefits in reducing muscle demands but can also delay effects of fatigue in low-back region and increase endurance by enabling wearers to perform more task cycles.

Application

Findings from this study may be beneficial to practitioners for setting guidelines on implementation of BSIEs in industrial bending tasks.