Gait asymmetry and variability in older adults during long-distance walking: Implications for gait instability.

BACKGROUND Physical exercise, such as walking, is imperative to older adults. However, long-distance walking may increase walking instability which exposes them to some fall risks. OBJECTIVE To evaluate the influence of long-distance walking on gait asymmetry and variability of older adults. METHOD Sixteen physically active older adults were instructed to walk on a treadmill for a total of 60 min. Gait experiments were conducted over-ground at the baseline (before treadmill-walk), after first 30 min (30-min) and second 30 min (60-min) of the walk. In addition to spatiotemporal parameters, median absolute deviation of the joint angular velocity was measured to evaluate gait asymmetry and gait variability. FINDINGS There were significant differences in the overall asymmetry index among the three time instances (Partial η2 = 0.77, p < .05), predominantly contributed by the ankle (Partial η2 = 0.31, p < .017). Long-distance walking significantly increased the average and maximum median absolute deviation of the ankle at both sides (W ≥ 0.19, p < .05), and knee at the non-dominant side (W = 0.44, p < .05). INTERPRETATION At 30-min, the older adults demonstrated a significantly higher asymmetry and variability at the ankle, which implied higher instability. Continue walking for an additional 30 min (60-min) further increased variability of the non-dominant limb at the knee joint. Walking for 30 min or more could significantly reduce walking stability.