Assessment of the 4-meter walk test test-retest reliability and concurrent validity and its correlation with the five sit-to-stand test in chronic ambulatory stroke survivors

Background: The 4-meter walk test (4-MWT) is a widely used measure to assess gait speed in the elderly but has not been validated for stroke survivors to date. Objectives: To assess the test-retest reliability and concurrent validity of the 4-MWT compared to the 10-meter walk test (10-MWT) as a measure of gait speed in chronic post-stroke. Secondary outcome measure: to assess the correlation of both gait measures with the 5 times sit-to-stand test (5TSTS).Methods: A cross-sectional observational study was conducted. Reliability was assessed by intraclass correlation coefficient (ICC2,1), standard error of measurement (SEM) and minimal detectable change (MDC-95%). Bland & Altman analysis was used to quantify agreement between the 4-MWT and the 10-MWT. Two consecutive walking trials of the 4-MWT and 10-MWT followed by 5TSTS were performed all on the same day. A single researcher made all measurements.Results: Thirty-six chronic ambulatory post-stroke (average age 58.56 +/- 11.28 years) were analyzed at their self-selected walking speed with a dynamic start. The 4-MWT showed excellent concurrent validity and test-retest reliability: ICC2.1 = 0.991 (95% CI: 0.983, 0.996); SEM= 0.032 and MDC-95% = 0.090 m/second) with a strong positive correlation with the 10-MWT (r = 0.957, p < 0.001). The Bland & Altman analysis showed a concordance of-0.05 m/second bias (p = 0.039) (95% limits of agreement: 0.20 to-0.29 m/second). The paired t-test showed no statistically significant difference in the mean of both walking tests (p < 0.091). How-ever, there was only moderate correlation between the two gait assessments and the 5TSTS.Conclusions: This study indicates excellent test-retest reliability concurrent validity and strong correlation be-tween 4-MWT and 10-MWT with a dynamic start at comfortable speed. The 4-MWT could be used as a measure of gait speed in both outpatients and home settings in chronic ambulatory stroke survivors.