The Reliability and Validity of Measures of Gait Variability in Community-Dwelling Older Adults

Objective: To examine the test-retest reliability and concurrent validity of variability of gait characteristics. Design: Cross-sectional Study. Setting: Research laboratory. Participants: Older adults (N=558) from the Cardiovascular Health Study. Interventions: Not applicable. Main Outcome Measures: Gait characteristics were measured using a 4-m computerized walkway. SD determined from the steps recorded were used as the measures of variability. Intraclass correlation coefficients (ICC) were calculated to examine test-retest reliability of a 4-m walk and two 4-m walks. To establish concurrent validity, the measures of gait variability were compared across levels of health, functional status, and physical activity using independent t tests and analysis of variances. Results: Gait variability measures from the two 4-m walks demonstrated greater test-retest reliability than those from the single 4-m walk (ICC=.22-.48 and ICC=.40-.63, respectively). Greater step length and stance time variability were associated with poorer health, functional status and physical activity (P <.05). Conclusions: Gait variability calculated from a limited number of steps has fair to good test-retest reliability and concurrent validity. Reliability of gait variability calculated from a greater number of steps should be assessed to determine if the consistency can be improved.