Measurement of a true V·O_2max during a ramp incremental test is not confirmed by a verification phase

The accuracy of an exhaustive ramp incremental (RI) test to determine maximal oxygen uptake (V·O_2max) was recently questioned and the utilization of a verification phase proposed as a gold standard. This study compared the oxygen uptake (V·O₂) during a RI test to that obtained during a verification phase aimed to confirm attainment of V·O_2max. Sixty-one healthy males [31 older (O) 65 ± 5 yrs; 30 younger (Y) 25 ± 4 yrs] performed a RI test (15-20 W/min for O and 25 W/min for Y). At the end of the RI test, a 5-min recovery period was followed by a verification phase of constant load cycling to fatigue at either 85% (n = 16) or 105% (n = 45) of the peak power output obtained from the RI test. The highest V·O₂ after the RI test (39.8 ± 11.5 mL·kg^-1·min^-1) and the verification phase (40.1 ± 11.2 mL·kg^-1·min^-1) were not different (p = 0.33) and they were highly correlated (r = 0.99; p < 0.01). This response was not affected by age or intensity of the verification phase. The Bland-Altman analysis revealed a very small absolute bias (-0.25 mL·kg^-1·min^-1, not different from 0) and a precision of ±1.56 mL·kg^-1·min^-1 between measures. This study indicated that a verification phase does not highlight an under-estimation of V·O_2max derived from a RI test, in a large and heterogeneous group of healthy younger and older men naïve to laboratory testing procedures. Moreover, only minor within-individual differences were observed between the maximal V·O₂ elicited during the RI and the verification phase. Thus a verification phase does not add any validation of the determination of a V·O_2max. Therefore, the recommendation that a verification phase should become a gold standard procedure, although initially appealing, is not supported by the experimental data.