How Age and Pace of Work Affect Movement Variability During Repetitive Assembly Tasks

Abstract

During production, companies aim to ensure optimal productivity and quality. With this in mind, workstation designers tend to assume that operators will perform tasks in a uniform manner, and tend not to include movement variability parameters in their designs. The aim of this study was to characterise movement variability during repetitive assembly tasks performed at a defined pace. 62 right-handed men in three different age groups were asked to affix a handle on a base with two nuts at two different paces. Particular attention was paid to how two factors influenced movement variability: the operator’s and the pace of work. Variability was observed in assembly way of doing when the procedure was not imposed. The variability observed during assembly, as performed for this study, was unaffected by operators’ age or the pace of work. No effect of variability was observed on the duration of assembly cycles, nor on the adaptation to changes in pace. In contrast, variability allowed operators alternatives to repetitive movement which could potentially exert strain on the locomotor system. Allowing operators the possibility to spontaneously use variable movements during repetitive tasks appears to be an important element to consider when designing workstations.