Balance control during stair descent on compliant surface is associated with knee flexor and ankle plantar flexor strength in older adults.

Balance and lower limb strength deficits are associated with a high incidence of falls in older adults. This study investigated the association between balance control during and after stair descent onto a compliant surface and lower limb strength. Thirty-five women and 14 men participated in this study. Stair descent time, mean center of pressure velocity in anteroposterior and mediolateral direction during stair descent (CoP V and CoP V), and CoP velocity in the first 5 s of restabilization phase (CoP V) were evaluated. Bilateral strength of the knee flexors and extensors, and ankle plantar and dorsal flexors was evaluated. Spearman correlation analysis with Bonferroni correction yielded a significant association between the strength of the knee flexors on the trailing limb and stair descent time in women (r = 0.502, p = 0.002, R = 0.246). The same analysis in men revealed a significant association between the strength of the knee flexors on the trailing limb and CoP V (r = -0.820, p < 0.001, R = 0.280) and CoP V (r = -0.697, p = 0.006, R = 0.359). The strength of the ankle plantar flexors on the trailing limb was significantly associated with stair descent time (r = 0.684, p = 0.007, R = 0.429) and CoP V (r = -0.723, p = 0.003, R = 0.408) in men. Stair descent balance control is associated with knee flexion strength on trailing limb in women, and with ankle plantar flexion and knee flexion strength on the same limb in men.