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

This study aimed to investigate the test-retest reliability, mean, and individual responses in the measurement of maximal oxygen consumption ((VO2max)-O-center dot) 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 (VO2)-O-center dot from the CPET ((VO2CPET)-O-center dot) and verification phase ((VO2verification)-O-center dot) 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) x method (CPET vs. verification phase) interaction (p = 0.896) and no main effect for method (p = 0.459). However, test 1 (39.2 mL<middle dot>kg(-1)<middle dot>min(-1)) was significantly higher than test 2 (38.3 mL<middle dot>kg(-1)<middle dot>min(-1)) (p = 0.043). The (VO2CPET)-O-center dot (ICC = 0.984; CoV = 1.98%; SEM = 0.77 mL<middle dot>kg(-1)<middle dot>min(-1); MD = 2.14 mL<middle dot>kg(-1)<middle dot>min(-1)) and (VO2verification)-O-center dot (ICC = 0.964; CoV = 3.30%; SEM = 1.27 mL<middle dot>kg(-1)<middle dot>min(-1); MD = 3.52 mL<middle dot>kg(-1)<middle dot>min(-1)) demonstrated "excellent" reliability. Two subjects demonstrated a test 1 (VO2CPET)-O-center dot that exceeded the test 2 (VO2CPET)-O-center dot, and one subject demonstrated a test 1 (VO2verification)-O-center dot that exceeded the test 2 (VO2verification)-O-center dot by more than the respective CPET and verification phase MD. One subject demonstrated a (VO2CPET)-O-center dot that exceeded the (VO2verification)-O-center dot, and one subject demonstrated a (VO2verification)-O-center dot that exceeded the (VO2CPET)-O-center dot by more than the MD. These results demonstrate the importance of examining the individual responses in the measurement of the (VO2max)-O-center dot and suggest that the MD may be a useful threshold to quantify real individual changes in (VO2)-O-center dot.