Fractional Utilization of V˙O2max-A Key Performance Determinant in Endurance Sports?

Identifying physiological factors that underly elite performance in endurance sports drives the work of many practitioners and researchers. Current models outline the maximal oxygen uptake (V˙O2max), fractional utilization of V˙O2max (%V˙O2max) at lactate threshold (LT) or competition intensity, and gross mechanical efficiency or economy as key determinants of endurance performance. While the importance of V˙O2max and efficiency/economy has been confirmed repeatedly, less conclusive evidence has been presented on %V˙O2max. In this review, we provide a narrative overview of the current literature on %V˙O2max as one of the performance-determining variables in endurance sports, and whether it can be improved through training.

Out of the 35 studies assessing the relationship between %V˙O2max and performance, only a few studies confirm a substantial relationship between %V˙O2max and performance. This holds for %V˙O2max at a specific physiological "landmark," such as LT and %V˙O2max at a competition-specific intensity. Additionally, there is limited evidence suggesting that %V˙O2max can be systematically altered through training in trained athletes. Methodological differences in the assessment of V˙O2max, LT, and endurance performance across the included studies, as well as variation in the training interventions, confound the interpretation of the findings.

According to the current literature, %V˙O2max at LT or competition intensity does not seem to be a strong predictor of endurance performance. Practical recommendations on how to improve %V˙O2max via training can currently not be given. We encourage researchers to collect and publish data on %V˙O2max for a more comprehensive conclusion about its role for endurance performance.