Aerobic Capacity at the Limits of Professional Cycling: Field-Based Estimates of V˙O2max

Purpose : Maximal oxygen uptake ( ) is a primary determinant of endurance performance. However, its upper physiological limits remain unknown, partly due to the limited ecological validity of laboratory testing. We aimed to estimate power output and during decisive competitive efforts in a world-class male cyclist. Methods : Competition data during the 2024 and 2025 seasons were analyzed. We first validated the model for estimating power output during competition efforts (accounting for gravitational, aerodynamic, and rolling resistance forces) against publicly available power meter data in different professional cyclists. A model for estimating (with adjustments for altitude, gross efficiency, and fractional utilization based on effort duration and competitive context) was also validated in a former Grand Tour winner for whom laboratory measures were available. Then, we estimated the mean power output during 4 key climbing efforts, and back-calculated . Results : Power output (mean absolute error = 11.7 W, bias = −9.5 W, 95% limits of agreement = −32.4 to 13.4 W) and estimations (mean difference from laboratory measurement = 0.9 mL·kg −1 ·min −1 ) showed acceptable validity. estimations in the world-class cyclist ranged 90 to 102 mL·kg −1 ·min −1 for assumed gross efficiency 22% to 24%, with a mean of ∼96 mL·kg −1 ·min −1 across multiple efforts differing in duration (17–40 min), altitude (723–1444 m.a.s.L.) and accumulated fatigue. Conclusions : Using competition-derived data and conservative physiological assumptions, this study provides potential evidence of an exceptionally high in a world-class cyclist. These findings extend beyond commonly reported values and might support the utility of field-based analyses for exploring the upper limits of endurance performance.