Use of the Six-Minute Walk Test Poststroke: Is There a Practice Effect?

Abstract 

Liu J, Drutz C, Kumar R, McVicar L, Weinberger R, Brooks D, Salbach NM. Use of the six-minute walk test poststroke: is there a practice effect?

Objectives

To determine whether a practice effect occurs across 2 trials of the six-minute walk test (6MWT) among community-dwelling people within 1 year poststroke and to identify characteristics distinguishing people who show a practice effect from those who do not.

Design

Secondary analysis of scores on 2 trials of the 6MWT administered approximately 30 minutes apart at baseline in a randomized controlled trial.

Setting

General community.

Participants

People (N=91) living in the community with a residual walking deficit within the first year of a first or recurrent stroke.

Interventions

Not applicable.

Main Outcome Measure

Distance walked on the 6MWT.

Results

Mean 6MWT scores ± SD for trials 1 and 2 were 196±119m and 197±126m, respectively (n=83). The mean difference in 6MWT performance across trials was 0±35m (95% confidence interval [CI], –7 to 8m). The Pearson correlation coefficient between 6MWT distances was .96 (P<.001), and the intraclass correlation coefficient was .98 (95% CI, .97–.99). The Bland-Altman plot showed no clear pattern. Participants whose improvement was equal to or greater than the minimal detectable change of 29m between trials (14%) did not significantly differ from those in the rest of the study sample; however, they tended to be younger (P=.05) and more likely to have a mild or moderate gait deficit (P=.06).

Conclusions

Findings do not support a practice effect across 2 trials of the 6MWT in individuals within 1 year poststroke. Thus, a practice walk does not appear necessary. Further research is recommended to evaluate the influence of young age, acute stroke, and mild-to-moderate gait deficit on practice effects.

Key Words: Rehabilitation, Stroke, Walking

List of Abbreviations: ADLs, activities of daily living, BBS, Berg Balance Scale, CI, confidence interval, COPD, chronic obstructive pulmonary disease, ICC, intraclass correlation coefficient, MDC, minimal detectable change, 6MWT, six-minute walk test, 12MWT, twelve-minute walk test, 2MWT, two-minute walk test, V̇o₂max, maximal oxygen uptake