ML Com Displacement for Older Adults During a Stair Descent on Challenging Surfaces

Introduction: Older adults (OA) decreased neuromuscular function leads to compensatory strategies to reduce the likelihood of falling, including larger, more variable medio-lateral (ML) center of mass (COM) displacement than young adults (YA) when performing acts of daily living, such as stair descent. Yet, it is unknown if this reduced neuromuscular function compromises their ability to successfully respond to external challenges, such as uneven or slick stair surfaces.

Objective: To determine the ML COM displacement for both OA and YA during a stair descent on a normal, uneven, and slick surface.

Methods: Six YA and 7 OA had ML COM displacement quantified during a stair descent on three surfaces (normal, uneven, and slick), and then, submitted to RM ANOVA to test main effect and interaction between surface (normal, uneven, and slick) and age (young and older adults).

Results: Significant surface by age interactions for range (p=0.006) and minimum (p=0.004) ML COM displacement were observed. The OA exhibited a larger range of ML COM displacement than YA, because OA increased in range and decreased minimum ML COM displacement on the uneven (p=0.022; p=0.001) and slick (p=0.008; p=0.032) surfaces, whereas, YA exhibited no significant change due to surface (p > 0.05).