Validation of three functional tests against the 6-minute walk test in individuals with obesity

The six-minute walk test (6MWT) is one of the most commonly-used assessments of functional capacity. However, its length and space requirements can limit feasibility in busy clinical settings. There is limited evidence on the validity of shorter or alternative functional tests compared to the 6MWT in individuals with obesity. Therefore, this study aimed to evaluate the concurrent validity of the distance covered during the first two minutes of the 6-minute walk test (2'6MWT), the 2-minute step test (2MST) and the 1-minute sit-to-stand test (1STST) against the full 6MWT in individuals with obesity.

This was a cross-sectional study. Participants with obesity completed three functional tests-6MWT, 2MST and 1STST-on the same day. Spearman's rank correlation was used to assess the concurrent validity of the 2'6MWT, 2MST and 1STST in relation to the 6MWT.

A total of 59 individuals with obesity (16 men) participated in the study. Age was 34 (8.5) years (mean (standard deviation)), and body mass index was 40.9 (6.5) kg/m². The 2'6MWT demonstrated a strong correlation with the 6MWT (Spearman's rank correlation, r _s  = 0.87, p < 0.001), while the 2MST and the 1STST showed moderate and weak correlations, respectively (r _s  = 0.45, p < 0.001; r _s  = 0.31, p = 0.02).

The 2'6MWT may serve as a valid alternative to the 6MWT for assessing functional capacity in individuals with obesity, offering a shorter duration and potentially reducing fatigue. The 2MST may be a more suitable alternative to the 1STST in settings with limited space for walking tests.