REF-1016 · Borszcz et al., 2024 · International Journal of Sports Physiology and Performance, · Paper · PubMed
External validation: the 5-minute-power VO2max equation underestimated measured VO2max by 6.6 mL/kg/min on average, with limits of agreement from −17.2 to +3.8
Key Findings
The 5-minute-power equation underestimated measured VO2max by 6.6 mL/kg/min (95% credible interval −8.6 to −4.7), with 95% limits of agreement from −17.2 to +3.8 mL/kg/min.
49 male cyclists did a graded test and a 5-minute time trial on a stationary ergometer; the Sitko equation REF-1015 was applied to their 5-minute relative power.
Predicted VO2max was lower than measured by 6.6 mL/kg/min (95% credible interval −8.6 to −4.7).
95% limits of agreement: −17.2 (−22.7 to −12.3) and +3.8 (−1.0 to 9.5) mL/kg/min.
Authors: the proposed equation presented systematic bias in this sample.
Practical Application
Whenever a VO2max is estimated from 5-minute power, say the error out loud: the average miss was about 7 mL/kg/min and an individual can be off by 10 or more in either direction.
Never present the estimate as a test result, never compare two athletes with it, and do not read a change of a few mL/kg/min as progress.
The honest answer to "what is my VO2max" without a laboratory test is a range plus the 5-minute power itself, which is the number that moves training.
Limitations
Men only; ergometer rather than field power.
The authors offer an updated equation, but its coefficients are not in the abstract (abstract only was read), so none is given here.