Abstract
BACKGROUND: Cardiorespiratory fitness (CRF) is a fundamental component of physical fitness. While maximal oxygen uptake (VO(2)max) is the gold standard for quantifying CRF, standard maximal exercise tests using direct measurements VO(2)max are dependent on the availability of laboratory equipment, and thereby expensive and time consuming. Recently, an equation was formulated to indirectly estimate VO(2)max using the YMCA 3-minute step test. METHODS: The study included 15 Korean (KR) and 15 Vietnamese (VN) healthy adults aged 19-35 years. All subjects completed a YMCA 3-minute step test (YMCA 3MST) and a maximal exercise treadmill test to predict VO(2)max and VO(2)max measures, respectively. RESULTS: There was a significant relationship between VO(2)max predicted from the YMCA 3MST and actual VO(2)max measurements from the treadmill test (r = 0.80, p < 0.0001; KR group: r = 0.81, p < 0.0001; VN group: r = 0.93, p < 0.0001). Bland-Altman analysis revealed statistical agreement between tests, although there was a systematic overestimation of 3.36 mL/kg/min for the KR group. CONCLUSION: The equation for predicting VO(2)max from the YMCA 3MST was validated among the study subjects. However, future research should explore the validity and reliability of the YMCA 3MST equation for estimating VO(2)max in other populations.