Distance-Induced Changes in Walking Speed After Stroke: Relationship to Community Walking Activity

Abstract

Background and purpose: Physical inactivity is a major contributing factor to reduced health and quality of life. The total distance walked during the 6-Minute Walk Test is a strong indicator of real-world walking activity after stroke. The purpose of this study was to determine whether measurement of distance-induced changes in walking speed during the 6-Minute Walk Test improves the test's ability to predict community walking activity.

Methods: For 40 individuals poststroke, community walking activity (steps/d), the total distance walked during the 6-Minute Walk Test (6MWTtotal), and the difference between the distances walked during the final and first minutes of the test (Δ6MWTmin6-min1) were analyzed using moderated regression. Self-efficacy, assessed using the Activities-specific Balance Confidence scale, was also included in the model.

Results: Alone, 6MWTtotal explained 41% of the variance in steps/d. The addition of Δ6MWTmin6-min1 increased explanatory power by 29% (ΔR = 0.29, P < 0.001). The final model accounted for 71% of steps/d variance (F4,32 = 19.52, P < 0.001). Examination of a significant 6MWTtotal × Δ6MWTmin6-min1 interaction revealed a positive relationship between 6MWTtotal and steps/d, with individuals whose distances declined from minute 1 to minute 6 by 0.10 m/s or more presenting with substantially fewer steps/d than those whose distances did not decline.

Discussion and conclusions: Coassessment of distance-induced changes in walking speed during the 6-Minute Walk Test and the total distance walked substantially improves the prediction of real-world walking activity after stroke. This study provides new insight into how walking ability after stroke can be characterized to reduce heterogeneity and advance personalized treatments.

Figures

Figure 1.

Relationships between (A) total 6-minute walk test distance (6MWTtotal) and community walking activity (steps/day) and (B) 6MWTtotal and steps/day as moderated by distance-induced changes in speed, shown as the difference between the distances walked during minute 6 versus minute 1 of the 6MWT (Δ6MWTmin6–min1).

Figure 2.

(A) Distance walked per minute, total 6MWT distance (6MWT), and community walking activity (steps/d) for two participants that exemplify the (B) non-endurant (i.e., those with a reduction in speed ≥ 0.10m/s) and endurant (i.e., those with a reduction in speed < 0.10 m/s) subgroups. (C) Total 6MWT distance, self-efficacy (ABC), steps/d for each subgroup. *P<0.05.