Design and cross-validation of prediction equation based on 6-minute walk test for assessing the cardiorespiratory efficiency in Iranian adolescent boys

Background and aims: Measurement of the cardiorespiratory fitness (CRF) (VO2peak) is not possible in every clinical and exercise setting due to complexity, cost, and time required. Submaximal field exercise test in an alternative method. Among exercise tests, the 6-minute walk test (6MWT) measures the maximal distance which a person can walk in 6 minutes. The purpose of the present study was to develop and cross-validate the VO2peak prediction equation based on the 6MWT in boys. Methods: VO2peak was measured by Bruce treadmill protocol with gas analysis in 157 healthy boys (13-17 years old). The 6MWT and anthropometric variables were measured according to standard methods. Data were analyzed using Kolmogorov-Smirnov test, Pearson correlation, and multiple regression analysis. Results: It was found that VO2peak of the boys had a significant correlation with 6MWT and anthropometric variables (r=0.318-0.853). VO2peak of the adolescent boys could be predicted by the distance walked in 6 minutes and body mass index (BMI) (R2 = 0.825, SEE = 2.81 mL/kg/min, P<0.001). When the new VO2peak prediction equation was applied for the subjects of this study, predicted VO2peak had a high correlation with measured VO2peak (r = 0.908, P<0.001). Conclusion: The 6MWT and proposed native VO2peak prediction equation could be used as a simple and safe tool for measurement of the CRF in the boys. It seems that physicians, exercise and fitness coaches, and physiotherapists could be able to evaluate the effect of medical and exercise prescriptions on the CRF of the boys via performing the 6MWT. This claim needs future studies.