Agreement between VO2max estimated from six-minute walk test and Chester step test in normal adults

Background: Cardiorespiratory fitness is a health-related component of overall physical fitness assessed as maximal oxygen uptake (VO₂max) during any physical activity. The six-minute walk test (6MWT) and Chester step test (CST) are two submaximal exercise tests routinely administered to estimate the VO₂max of an individual. Thus, the aim of this study was to assess whether an agreement exists between the VO₂max estimated by 6MWT and CST in normal adults.

Method: This crossover study was conducted with 80 healthy adults aged 18-40 years. All participants performed the 6MWT and CST on consecutive days. VO₂max from the 6MWTwas estimated using a prediction equation whereas from the CST using the graphical plot method.

Results: The mean VO₂max-6MWT and VO₂max-CST were 43.53 ± 4.65 ml/kg/min and 38.34 ± 4.94 ml/kg/min respectively. The Bland and Altman analysis revealed that the mean difference between VO₂max-6MWT and VO₂max-CST was 5.19 ± 5.50 ml/kg/min which exceeded the maximum acceptable difference of 3 ml/kg/min decided a priori. The line of equality (X axis) did not fall within the confidence interval of the mean difference indicating that VO₂max estimated using the two submaximal exercise tests significantly differ from each other. The standard error of mean was 0.61 ml/kg/min and the standard error of limits of agreement was 1.06 ml/kg/min.

Conclusion: VO₂max estimated from the six-minute walk test and Chester step test show no agreement with each other.