Knechtle, BeatLeite , Luciano BernardesDuric, SasaCuk, IvanAndrade, Marilia SantosScheer, VolkerNikolaidis, Pantelis TheoWeiss, KatjaRosemann, ThomasForte, PedroRatko Peric2025-10-172025-10-172025Knechtle, Beat; Leite , Luciano Bernardes; Duric, Sasa; Cuk, Ivan; Andrade, Marilia Santos; Scheer, Volker; Nikolaidis, Pantelis Theo; Weiss, Katja; Rosemann, Thomas; Forte, Pedro (2025). Sex differences in performance and pacing in the greatest Quintuple Iron ultra-triathlon race in history: The IUTA World Championship 2024 in France. Plos One. ISSN 1932-6203. 20:9, p. 1-151932-6203http://hdl.handle.net/10198/34851Pacing in ultra-triathlon has been investigated by analyzing lap times from Double to Deca Iron ultra-triathlon for World Cup races but not for a World Championship. The present study aimed to investigate pacing in ultra-triathletes competing in the fastest and largest World Championship in Quintuple Iron ultra-triathlon ever held in history. A total of 11 female and 24 male finishers who completed the 2024 Quintuple Ultra Triathlon World Championship in Colmar, France, were analyzed. Independent t-tests assessed sex-based performance variations with effect sizes (Cohen's d). A two-way ANOVA evaluated the effects of sex and performance quartiles on cycling and running, with eta squared (eta(2)) used to measure effect sizes. Overall, men were slower in swimming and cycling and faster in running and overall race time. The variability in lap times was similar in cycling for both women and men but higher in running for women. There was a significant interaction between sex and performance quartiles in cycling but not running. For cycling, the variability in performance was higher in men compared to women; for running, it was similar for both women and men. The finding that women outperformed men in swimming and cycling, likely due to the elite nature of the World Championship, which featured a highly selected and committed female cohort with a high completion rate. While both sexes showed consistent pacing in cycling, women exhibited greater variability in running, possibly due to more frequent breaks.engStrategiesExercisejournal article10.1371/journal.pone.0331563