Criterion-related validity and reliability of the 6-minute walk test in adults according to sex, age and physical activity level: The ADULT-FIT project

Abstract

This study aimed to analyse the criterion-related validity and reliability of the 6-minute walk test (6MWT) to assess cardiorespiratory fitness in the adult population, according to sex, age and physical activity level. Sociodemographic and anthropometric measurements, a treadmill maximal test, and the 6MWT were performed on 410 adults aged 18–64 years. Measured VO2max was associated with the total distance in the 6MWT and estimated VO2max by Burr´s and Manttari´s equations (R2= 0.35, 0.61 and 0.61, respectively, all p< 0.01; SEE= 6.564 - 5.089 ml* kg-1 * min-1, %SEE= 11.80 – 15.30). The stepwise linear regression analysis showed that the total distance in the 6MWT, sex, age, physical activity level and body fat mass (%) explained 75% variance of measured VO2max (SEE= 4.203 ml* kg-1 * min-1, %SEE= 9.78, p< 0.001). The systematic error in the total distance in the 6MWT was 0.87-m (p< 0.001). The ICC showed excellent agreement (0.99, p< 0.001), with low error values and most of the MCD95 close to 0. The 6MWT was valid and reliable to assess cardiorespiratory fitness in adults aged 18–64 years. Validity was greater in the older age and non-active groups. Reliability did not depend on sex, age, nor physical activity level.