Reproducibility of peak oxygen consumption and the impact of test variability on classification of individual training responses in young recreationally active adults

Summary This study investigated whether VO 2 peak is reproducible across repeated tests before ( PRE ) and after ( POST ) training, and whether variability across tests impacts how individual responses are classified following 3 weeks of aerobic exercise training (cycle ergometry). Data from 45 young healthy adults (age: 20·1 ± 0·9 years; VO 2 peak, 42·0 ± 6·7 ml·min −1 ) from two previously published studies were utilized in the current analysis. Non‐responders were classified as individuals who failed to demonstrate an increase or decrease in VO 2 peak that was greater than 2·0 times the typical error of measurement (107 ml·min −1 ) away from zero, while responders and adverse responders were above and below this cut‐off, respectively. VO 2 peak tests at PRE (three total) and POST (three total) were highly reproducible ( PRE and POST average and single measures ICC s: range 0·938–0·992), with low coefficients of variation ( PRE :4·9 ± 3·1%, POST : 4·8 ± 2·7%). However, a potential learning effect was observed in the VO 2 peak tests prior to training, as the initial pretraining test was significantly lower than the third ( p = 0·010, PRE 1: 2 946 ± 924 ml·min −1 , PRE 3: 3 042 ± 919 ml·min −1 ). This resulted in fewer individuals classified as adverse responders for Test 3 compared to any combination of tests that included Test 1, suggesting that a single ramp test at baseline may not be sufficient to accurately classify the VO 2 peak response in young recreationally active individuals. Thus, it is our recommendation that the initial VO 2 peak test be used as a familiarization visit and not included for analysis.