What Is the Best Discipline to Predict Overall Triathlon Performance? An Analysis of Sprint, Olympic, Ironman® 70.3, and Ironman® 140.6 The aim of this work was to analyze the proportion of every triathlon discipline (swimming, cycling and running) and the importance of each individual discipline for predicting the overall performance of elite triathlets over various triathlon distances. Data from 2015 to 2020 (n = 16,667) of official races and athletes in sprint, Olympic distance, in 70.3- (Half-Ironman Distance) and 140.6- (Ironman Distance) competitions were included. The share of each discipline was calculated individually and compared with linear models according to route length, gender and power level. For each distance, automatic linear regression models were used, where the total power was considered as dependent variable.The best predictor for the sprint dance is cycling, for the Olympic distance the swimming, for which in 70.3 the cycling and for the in 140.6 running.Swimming is a better predictor for the Olympic distance than in the other triathlon distances.Cycling is a bad predictor for overall performance in in 140.6, and the importance of running for predicting the overall performance is highest in 140.6 and decreases with decreasing racetrack. Each discipline represents another relative content and other meaning to predict the overall performance depending on the triathlon distance. Swimming is the most important discipline in the sprint triathlon and over the Olympic distance, cycling in in 70.3 and run in 140.6. The whole work can be found under https://www.frontiersin.org/articles/10.3389/fhys.2021.654552/full