Changes in Contributions of Swim, Cycle, and Run Performances on Overall Triathlon Performance over a 26-year period The French sports scientist Romuald Lepers has studied how strong the disciplines swimming, cycling and running performance in a triathlon. For this he has taken the 50 fastest athletes about the short distance and the Ironman distance from the years 1989 to 2013.On the short distance, the athletes were swimming and running faster, but there was no change in cycling time and the total time. On the Ironman track the wheels and maturities and the total time were faster, but nothing happened when swimming.Swimming made about 18% on the short distance, running with 47% and 36% cycling made a much larger part.At the Ironman, cycling and run about 40%.
You can conclude that running on the short distance is crucial during cycling and running on the Ironman track is approximately equivalent. The whole evaluation can be found under https://pubmed.ncbi.nlm.nih.gov/26808853/