Impact of Passive Arm Support Exoskeletons on Shoulder and Torso Muscle Activation During Simulated Drilling Exertions at Different Heights and Directions

Passive arm support exoskeletons (ASEs) have attracted interest with the prospect of reducing shoulder musculoskeletal injuries. The objective of this study was to assess the impact of passive ASEs on electrical activation of shoulder and torso muscles while performing simulated vertical and horizontal drilling exertions by 17 experienced aircraft workers. The tasks included three vertical drilling heights (chin, head, overhead levels) and two horizontal drilling heights (eye, overhead levels), where participants performed five two-second exertions with one-second no-exertion times between successive drilling exertions. Electromyographic signals from the anterior and medial deltoids, trapezius, latissimus dorsi, erector spinae, biceps and triceps were captured. During vertical drilling exertions, ASEs significantly reduced dominant and non-dominant medial deltoid muscle activity, as well as activity in the non-dominant anterior deltoid, but not the dominant anterior deltoid. During horizontal drilling exertions, ASEs significantly decreased dominant and non-dominant anterior and medial deltoid muscle activity. ASEs significantly reduced non-dominant and dominant anterior and medial deltoid muscle activity during the time between drilling exertions in both the vertical and horizontal drilling directions. These results are encouraging in suggesting that ASEs reduce muscular exertion during drilling tasks commonly found in aircraft manufacturing. However, ASEs must be evaluated in worksite studies to better assess their efficacy.