Motor adaptation capacity as a function of age in carrying out a repetitive assembly task at imposed work paces

Abstract

. Motor adaptation capacity as a function of age in carrying out a repetitive assembly task at imposed work paces. Applied Ergonomics, Elsevier, 2017, 64, pp.47-55. 10 AbstractThe working population is getting older. Workers must adapt to changing conditions to respond to the efforts required by the tasks they have to perform. In this laboratory-based study, we investigated the capacities of motor adaptation as a function of age and work pace. Two phases were identified in the task performed: a collection phase, involving dominant use of the lower limbs; and an assembly phase, involving bi-manual motor skills. Results showed that senior workers were mainly limited during the collection phase, whereas they had less difficulty completing the assembly phase. However, senior workers did increase the vertical force applied while assembling parts, whatever the work pace. In younger and middle-aged subjects, vertical force was increased only for the faster pace. Older workers could adapt to perform repetitive tasks under different time constraints, but adaptation required greater effort than for younger workers. These results point towards a higher risk of developing musculoskeletal disorders among seniors.

Grasping an object at floor-level: Is movement strategy a matter of age?

“…However, older subjects tended to more frequently use strategies requiring less flexion of the knees (MStoop and Stoop). Similar age-related differences in the postural kinematics during repetitive lifting were previously reported (Shin et al, 2006, Burgess et al, 2009, Song and Qu, 2014, Gilles et al, 2017. In all cases, differences were observed between the strategies adopted by older and younger subjects when performing lifting tasks.…”

“…In this work, not only was the pace of work defined, but the instruction was that it had to be respected. Although subjects in the junior age-group were apparently able to readily adapt to changes of pace, older subjects, due to age-related changes in their functional capacities, had more difficulty (Gilles et al, 2017). Reducing the number of strategies used could be considered as a timesaver as it reduces the number of options to consider.…”

“…The angles were measured when the joint centre of the sacrum was located at its lowest point relative to the ground, and were compared to those measured for the reference posture (subject standing upright, arms aligned with the trunk) recorded at the start of the experimental session. The detailed procedure through which the angles were calculated was presented for the kinematic analyses of the full assembly task (Gilles et al, 2017).…”

“…With advancing age, changes to muscle properties can combine with a worker's capacity to repeat a physically demanding movement, such as collecting objects from the floor (Duchateau et al 2006, Gibo et al 2013. The capacity to repeat this movement will be all the more hampered when a rapid work pace is added to age-related constraints (Gilles et al, 2017). Nevertheless, numerous elements remain to be modulated when performing the movement.…”

“…A previous paper presented results from classical movement analysis performed on the same task (Gilles et al, 2017). This exhaustive analysis of the data provided us with an extensive range of information through which we could understand the physiological limitations involved in performing a task requiring squatting.…”