Analysis of Individual V˙O2max Responses during a Cardiopulmonary Exercise Test and the Verification Phase in Physically Active Women

Abstract

This study aimed to investigate the test–retest reliability, mean, and individual responses in the measurement of maximal oxygen consumption (V˙O2max) during a cardiopulmonary exercise test (CPET) and the verification phase during cycle ergometry in women. Nine women (22 ± 2 yrs, 166.0 ± 4.5 cm, 58.6 ± 7.7 kg) completed a CPET, passively rested for 5 min, and then completed a verification phase at 90% of peak power output to determine the highest V˙O2 from the CPET (V˙O2CPET) and verification phase (V˙O2verification) on 2 separate days. Analyses included a two-way repeated measures ANOVA, intraclass correlation coefficients (ICC2,1), standard errors of the measurement (SEM), minimal differences (MD), and coefficients of variation (CoV). There was no test (test 1 versus test 2) × method (CPET vs. verification phase) interaction (p = 0.896) and no main effect for method (p = 0.459). However, test 1 (39.2 mL·kg−1·min−1) was significantly higher than test 2 (38.3 mL·kg−1·min−1) (p = 0.043). The V˙O2CPET (ICC = 0.984; CoV = 1.98%; SEM = 0.77 mL·kg−1·min−1; MD = 2.14 mL·kg−1·min−1) and V˙O2verification (ICC = 0.964; CoV = 3.30%; SEM = 1.27 mL·kg−1·min−1; MD = 3.52 mL·kg−1·min−1) demonstrated “excellent” reliability. Two subjects demonstrated a test 1 V˙O2CPET that exceeded the test 2 V˙O2CPET, and one subject demonstrated a test 1 V˙O2verification that exceeded the test 2 V˙O2verification by more than the respective CPET and verification phase MD. One subject demonstrated a V˙O2CPET that exceeded the V˙O2verification, and one subject demonstrated a V˙O2verification that exceeded the V˙O2CPET by more than the MD. These results demonstrate the importance of examining the individual responses in the measurement of the V˙O2max and suggest that the MD may be a useful threshold to quantify real individual changes in V˙O2.