Performance on a test of rapid stepping in community-dwelling older adults: validity, relative and absolute reliability and minimum detectable change.

Reduced stepping speed is associated with balance deficits and falls in older adults. We evaluated psychometric properties of a test of rapid stepping, the Thirty-Rapid-Step test (30-RST) in 37 community-dwelling older adults. Participants performed the 30-RST, dynamic (step execution time, five-times-sit-to-stand test, gait speed, maximum step length and four-square-step test) and static (single-leg-stance-time and postural sway) performance-based tests. Relationships between 30-RST and performance-based tests were evaluated with Spearman's rho. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), 95% limits of agreement and minimum detectable change at the 95% confidence level (MDC95) were computed for the 30-RST. Relationships between 30-RST and dynamic measures were moderate to very good (r = -0.35-0.73, p < 0.05); however, relationships between 30-RST and static balance were weak (r = 0.04-0.19, p > 0.05). The ICC2,1 was 0.85 for 30-RST indicating excellent test-retest reliability. SEM expressed as a percent of mean 30-RST was 8.2%, indicating low measurement error. The MDC95 was 9.4 s, and MDC95 expressed as a percent of mean 30-RST was moderately low at 22.6%. The 30-RST is a valid measure of dynamic balance and mobility with excellent relative and absolute reliability, and may be a useful measure in geriatric clinical settings and studies investigating balance in healthy community-dwelling older adults.