An Investigation of the Impact of Fatigue and Aging on the Performance of Spatially Constrained Assembly Tasks Commonly Found in the Construction Industry

Abstract

The goal of this study was to investigate the effects of fatigue and aging on the performance of spatially constrained drilling tasks that are observed within the construction industry. Eight younger (18–35 years) and eight older (45–60 years) participants were selected from the local community. Participants were presented with two conditions of localized muscle fatigue in the anterior musculature of the shoulder (No Fatigue and a Fatigue condition). During each condition, participants completed a series of drilling tasks at three levels of task difficulty; as defined by the spatial arrangement of the fasteners. The dependent variables; task completion time, error rate and muscle activation patterns (shoulder APDF and coactivity indices of the upper and lower arm), were measured using observations and electromyography of the muscles of the upper extremity. The presence of localized shoulder fatigue significantly reduced task completion times for both age groups at all levels of task difficulty. Further, error rate was higher for the younger age group in the fatigue condition compared to the no fatigue condition; no such differences were seen for the older subjects. Muscle activity decreased for the anterior deltoid in the fatigue condition, and concurrent increases were observed in the coactivity indices of the upper and the lower arm musculature.