Walking Speed Affects Gait Coordination and Variability Among Older Adults With and Without Mobility Limitations

Objective: To determine if poorer gait variability and gait coordination among mobility-limited older adults is related to their slower walking speed. Design: Cross-sectional analysis. Setting: University research laboratory. Participants: Community-dwelling adults (N=69) 68 years or older with (Short Physical Performance Battery score ≤9; n=37) and without (n=32) mobility limitations. Interventions: Not applicable. Main Outcome Measures: The variability of step length, swing time percent, and step width. Gait coordination was assessed along with the Phase Coordination Index. Results: The usual pace gait speed of those without mobility limitations was faster (1.22±0.14m/s vs 0.71±0.14m/s; P<.001) and less variable in all gait characteristics (all P<.001), with the exception of step width (P=.185), than those with limitations. When those without limitations slowed their walking pace (0.71m/s±0.14), their gait coordination became poorer (P<.001), and the variability of all gait characteristics increased (all P<.001) except for step width, which decreased (P=.002). When those without mobility limitations walked at a slow pace, they had better gait coordination (P=.008) and less variable step length (P=.014) and swing time percent (P=.036). The variability of stride time (P=.260) and step width (P=.385) were not significantly different than that of their peers with limitations. Conclusions: Increased variability in some gait characteristics of mobility-limited older adults appears to be related to their slower walking speed. Gait coordination and the variability of step length and swing time percent may reflect intrinsic differences in mobility-limited older adults that are independent of walking speed.