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 VAP and CoP VML), and CoP velocity in the first 5 s of restabilization phase (CoP V5) 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, R2 = 0.246). The same analysis in men revealed a significant association between the strength of the knee flexors on the trailing limb and CoP VAP (r = -0.820, p < 0.001, R2 = 0.280) and CoP VML (r = -0.697, p = 0.006, R2 = 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, R2 = 0.429) and CoP VAP (r = -0.723, p = 0.003, R2 = 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.