Validity and reliability of the Chester step test for prediction of the aerobic capacity among Iranian students

Background: Assessment of aerobic capacity is of vital importance in both general community and occupational settings. Valid, reliable and feasible tests are required to indicate the functionality of cardiopulmonary system. The present study was carried out aiming to evaluate the suitability of the Chester step test (CST) as a field test to measure the Iranians’ aerobic capacity.    Materials and Methods: In this descriptive study performed in 2016, 63 university students completed the Astrand-rhyming cycle ergometer test and the CST. Actual and predicted maximum rate of oxygen consumption (VO2 max) were recorded and their relationship was examined by Pearson's correlation coefficient and Bland-Altman plot. Repeatability was checked using intra-class correlation coefficient (ICC).  Results: Predicted and actual amounts of VO2 max were significantly correlated (r = 0.868, P < 0.001). The mean difference between them was -0.89 ml/kg/minute. ICC between CST and the retest CST (CSTretest) was 0.858. Conclusions: CST is a valid and reliable field test for the estimation of cardiorespiratory capacity among the study subjects. With its exclusive features (e.g. safety, convenience and ease of use), CST could be suggested as an alternative to other existing methods of estimating VO2 max; the applicability of the existing methods among Iranian individuals are unclear. However, like other estimation methods, special prudence should be adopted when dealing with critical health decisions.