Developing and Validating a Step Test of Aerobic Fitness among Elementary School Children

Purpose: The tests to estimate aerobic fitness among children require substantial space and maximum effort, which is often difficult for children. We developed a simple submaximal step test (Step Test of Endurance for Pediatrics, or STEP) and assessed its reliability, validity, and ability to estimate aerobic fitness among elementary school children.Method:Children aged 5-10 years completed the STEP with a protocol consisting of 0.1-, 0.2-, and 0.3-metre (4, 8, and 12 in.) step heights. Participants underwent treadmill testing with open circuit spirometry to determine actual maximal oxygen consumption (V ? o(2max)). Intra-class correlation coefficients (ICCs) assessed test-retest reliability of the STEP and its component tests. Multivariate linear regression assessed the associations between the STEP and V ? o(2max), adjusting for potential covariates such as age, sex, BMI, and comorbidity count. Results: The STEP showed excellent reliability (ICC >= 0.92; N = 170), irrespective of effort level during testing. Significant effort issues and collinearity among the independent variables led us to exclude children aged 5-6 years (n = 45) from the regression analysis. The final regression model for children aged 7-10 years with adequate effort (n = 111), as defined by a respiratory exchange ratio of 1.0 or more, showed that the STEP, sex, and BMI were significantly predictive of V ? o(2max) (R (2) = 0.51). Conclusions: This new, effort-independent step test can estimate the aerobic fitness of children aged 7-10 years. Regression equations to estimate V ? o(2max) from the STEP were provided.