Sex-specific differences in performance and pacing in the world's longest triathlon in history.

Sex differences in performance and pacing in triathlon have been studied for IRONMAN triathlons (3.8 km swimming, 180 km cycling and 42.195 km of running) and ultra-triathlons (i.e. Double-, Triple-, Quintuple- and Deca Iron ultra-triathlons) corresponding to 2x, 3x, 5x and 10x the IRONMAN triathlon distance. However, no study has to date investigated the sex difference in performance and pacing in the longest triathlon held in history, the Triple Deca Iron ultra-triathlon covering 114 km of swimming, 5,400 km of cycling and 1,266 km of running. A total of 14 triathletes (10 men and four women) competed in the 2024 Triple Deca Ultra Triathlon in Desenzano del Garda, with four men and three women officially finishing the race within the time limit. The data were analyzed to investigate performance differences across disciplines (i.e. swimming, cycling, and running), pacing strategies and sex differences. Variability was assessed using each discipline's coefficient of variation (CV). The relation-ships between CV and overall rankings were examined using linear regression analysis. Men were faster in swimming (12.4%), cycling (24.8%) and running (8.5%). Cycling showed the greatest pacing variability, while running exhibited steadier pacing, with more consistent athletes performing better overall, reflecting the unique endurance challenges of this segment. Overall, men were faster than women in all split disciplines, with the highest sex difference in cycling and the smallest in running. The analysis revealed significant differences in both cycling and running times among athletes. The variability in cycling times indicates diverse pacing strategies and endurance levels, while the running times further highlight the individual performance dynamics of the athletes. The results illustrate how variability in pacing affects cumulative performance and final rankings.