Validity of the two-minute walk test to assess exercise capacity and estimate cardiorespiratory fitness in individuals after stroke: a cross-sectional study

ObjectivesThe purpose of this study was to investigate the construct validity of the 2-minute walk test (2MWT) to assess the exercise capacity and the criterion-concurrent validity of the 2MWT and the 6-minute walk test (6MWT) to estimate the cardiorespiratory fitness of ambulatory individuals with chronic stroke. In addition, to provide an equation to predict the distance covered in the 6MWT and another to predict the peak oxygen consumption (VO2peak) for these individuals.MethodsThis is a cross-sectional and prospective study. A convenience sample with 57 individuals with chronic stroke was recruited. The 2MWT, the 6MWT and the cardiopulmonary exercise test (CPET) were performed in a laboratory. The Spearman's correlation coefficient was used to investigate the validity. To develop the equations, stepwise multiple linear regression analysis was used.ResultsA significant correlation of very high magnitude between the distance covered in the 2MWT and the 6MWT was found (r(s) = 0.93; p < 0.001). A significant correlation of moderate magnitude between the distance covered in the 2MWT and the VO2peak (r(s) = 0.53; p < 0.001) similar to the correlation between the 6MWT and the VO2peak (r(s) = 0.55; p < 0,001) were found. Furthermore, an equation was developed to predict the VO2peak (R-2 = 0.690; p < 0.001; VO2peak = 13.532 + 0.078*distance walked in the 2MWT +4.509*sex-0.172*age), and another to predict the distance covered in the 6MWT (R-2 = 0.827; p < 0.001; MWT = -1.867 + 3.008*distance walked in the 2MWT).Conclusion2MWT showed adequate construct and concurrent validity. Furthermore, it is possible to use the prediction equations developed to estimate the VO2peak or the distance covered in the 6MWT.