Evaluating Sit-to-stand Across Various Armrest Configurations in Older Adults with Limited Mobility

Abstract

This study investigated the differences in kinematics and kinetics of the lower limbs and load applications of the upper limbs across various armrest configurations. Configurations tested include nine combinations through three anterior-posterior (AP) positions (close, middle, far) and three height positions (low, middle, high). A linked-segment model was used to calculate kinetics and kinematics of the lower limbs using an inverse dynamic analysis. Forces were recorded from two force plates below the feet and two load cells embedded in the armrests. Farther armrest AP positions yielded higher pulling forces and were encountered with greater moments about the knees and hips. Higher armrest positions yielded greater pulling forces and were encountered with reduced moments about the hips and ankles. Stability was best in far and high positions. Potential applications for this research include an armrest design guideline for use by seating companies, rehab therapists, and for potential armrest products.