Differences in trunk kinematics and ground reaction forces between older and younger adults during lifting

Abstract

Age-related changes in trunk kinematics in lifting have received little attention despite a documented increased risk of musculoskeletal injury with age. This study examined the responses in trunk kinematics and ground reaction forces of older and younger subjects during lifting. Ten older (55-63 years) and ten younger (19-29 years) adults performed lifting tasks in six different conditions. A lumbar motion monitor was used to measure the subjects' trunk kinematics and a force platform was used to measure the ground reaction forces during the lifting motion. The results of this study showed that age had a significant (p<0.05) effect on the transverse plane (axial twisting) trunk kinematics variables (peak velocity and peak acceleration) but did not affect ground reaction forces or other trunk kinematics variables. The peak transverse velocity was 40% lower and peak transverse acceleration was 30% lower in the older subjects as compared to the younger subjects. Relevance to industry: This study presents the postural adaptation of older subjects to dynamic lifting tasks. Results can be used to understand the risks of older work population in manual material handling tasks.