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

Brach JS, Perera S, Studenski S, Newman AB. The reliability and validity of measures of gait variability in community-dwelling older adults.ObjectiveTo examine the test-retest reliability and concurrent validity of variability of gait characteristics.DesignCross-sectional study.SettingResearch laboratory.ParticipantsOlder adults (N=558) from the Cardiovascular Health Study.InterventionsNot applicable.Main Outcome MeasuresGait 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.ResultsGait 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).ConclusionsGait 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.