The reliability and validity of measures of gait variability in community-dwelling older adults.

Abstract

To examine the test-retest reliability and concurrent validity of variability of gait characteristics. Cross-sectional study. Research laboratory. Older adults (N=558) from the Cardiovascular Health Study. Not applicable. 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. 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). 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.