AUTHOR=Noakes Timothy , Buga Alex , Volek Jeff , Prins Philip 

TITLE=Identification of a reverse crossover point during moderate-intensity exercise (>6 h; 69% VO2max) in a world-class triathlete—A secondary analysis

JOURNAL=Frontiers in Nutrition

VOLUME=Volume 12 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1627404

DOI=10.3389/fnut.2025.1627404

ISSN=2296-861X

ABSTRACT=Graphical abstractRe-analysis results (Left) and takeaway messages (Right) are summarized above. RCOP, reverse crossover point. Figure created with Biorender.com.Reverse Crossover Point (RCOP) analysis showing a man on an exercise bike and running, indicating training intensity. A graph illustrates substrate oxidation levels over time, with fat oxidation surpassing carbohydrate oxidation. Key takeaways: Fat oxidation increased significantly despite carbohydrate intake, suggesting additional carbohydrate sources and reliance on lipids for energy.