The Lower Limb Stiffness, Moments, and Work Mode During Stair Descent Among the Older Adults.

Objective: Lower limb stiffness strategies and work mode changes between young and older adults during stair descent are unclear. This study investigated the effect of aging on the lower limb stiffness, moments, and joint work mode during stair descent.

Design: Twenty young adults and 20 older adults were recruited from the local community for stair descent test. Kinematics and kinetics data were collected by Vicon system and Kistler force plate. The lower limb stiffness, moments, and work mode were calculated and assess between groups.

Results: No significant differences in gait parameters were detected between groups. Compared with young adults, older adults have decreased leg stiffness, knee and ankle stiffness, increased peak hip extension moment, hip stiffness, and ankle work contribution.

Conclusions: The older adults actively reduce the lower limb stiffness to reduce the risk of injury during stair descent. The hip joint strategy reduces the risk of forwarding falls and ankle joint compensation work mode to make up for the lack of knee extension strength. This provides a reference for the focus of exercise intervention and rehabilitation strategies for older adults.