AUTHOR=Murias Juan M. , Pogliaghi Silvia , Paterson Donald H. 

TITLE=Measurement of a True V˙O2max during a Ramp Incremental Test Is Not Confirmed by a Verification Phase

JOURNAL=Frontiers in Physiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.00143

DOI=10.3389/fphys.2018.00143

ISSN=1664-042X

ABSTRACT=<p>The accuracy of an exhaustive ramp incremental (RI) test to determine maximal oxygen uptake (<inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mstyle class="text"><mml:mtext>V</mml:mtext></mml:mstyle><mml:mo mathsize="10.5pt" mathcolor="black">˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2max</sub>) was recently questioned and the utilization of a verification phase proposed as a gold standard. This study compared the oxygen uptake (<inline-formula><mml:math id="M3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mstyle class="text"><mml:mtext>V</mml:mtext></mml:mstyle><mml:mo mathsize="10.5pt" mathcolor="black">˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>) during a RI test to that obtained during a verification phase aimed to confirm attainment of <inline-formula><mml:math id="M4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mstyle class="text"><mml:mtext>V</mml:mtext></mml:mstyle><mml:mo mathsize="10.5pt" mathcolor="black">˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2max</sub>. 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% (<italic>n</italic> = 16) or 105% (<italic>n</italic> = 45) of the peak power output obtained from the RI test. The highest <inline-formula><mml:math id="M5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mstyle class="text"><mml:mtext>V</mml:mtext></mml:mstyle><mml:mo mathsize="10.5pt" mathcolor="black">˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub> after the RI test (39.8 ± 11.5 mL·kg<sup>−1</sup>·min<sup>−1</sup>) and the verification phase (40.1 ± 11.2 mL·kg<sup>−1</sup>·min<sup>−1</sup>) were not different (<italic>p</italic> = 0.33) and they were highly correlated (<italic>r</italic> = 0.99; <italic>p</italic> &lt; 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<sup>−1</sup>·min<sup>−1</sup>, not different from 0) and a precision of ±1.56 mL·kg<sup>−1</sup>·min<sup>−1</sup> between measures. This study indicated that a verification phase does not highlight an under-estimation of <inline-formula><mml:math id="M6" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mstyle class="text"><mml:mtext>V</mml:mtext></mml:mstyle><mml:mo mathsize="10.5pt" mathcolor="black">˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2max</sub> 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 <inline-formula><mml:math id="M7" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mstyle class="text"><mml:mtext>V</mml:mtext></mml:mstyle><mml:mo mathsize="10.5pt" mathcolor="black">˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub> elicited during the RI and the verification phase. Thus a verification phase does not add any validation of the determination of a <inline-formula><mml:math id="M8" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mstyle class="text"><mml:mtext>V</mml:mtext></mml:mstyle><mml:mo mathsize="10.5pt" mathcolor="black">˙</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2max</sub>. Therefore, the recommendation that a verification phase should become a gold standard procedure, although initially appealing, is not supported by the experimental data.</p>