Effect of time constraint on performance speed of a repetitive assembly task according to age

Repetitive work at required pace, as observed on assembly lines, is often characterized by reduced amounts of temporal margin of maneuver (TMM). Various epidemiological studies have shown that working under time constraints is particularly difficult for ageing workers. The aim of this study is to use movement analysis to improve characterization of the effect of having possible TMM during performance of a repetitive task, taking into account the age.
This laboratory study was conducted on 28 subjects (males) allocated into 2 age groups (younger participants: 25-35 years, and older participants: 55-65 years). They performed repetitive work for 50 minutes either at an imposed pace or at pace with TMM. At both work pace, assembly work with additional tasks (options) occurred randomly without increasing the allotted assembly time. The speed of the right wrist was analyzed using 3D modeling of the movements, based on the recordings by an optokinetic system.
The preliminary results show, for both groups, a significant increase (p < 0.001) in the speed of the right wrist during assembly work with options. Moreover, with or without option, the speed of the right wrist was significantly lower (p < 0.001) at the TMM pace than at the imposed pace in the younger participants, whereas no change was observed in the older participants between the two paces. At the imposed pace, the older participants were significantly slower (p < 0.01) than the younger participants.
This study shows that, in terms of regulating the speeds of movement, TMM seems to benefit younger workers whereas older workers appear to be able to take less advantage of it.