Personal best times in an Olympic distance triathlon and in a marathon predict Ironman race time in recreational male triathletes For male Ironman triathlets, we have correlated variables of body construction, training and experience with the conclusion time and examined which variables are best correlated with the Ironman competition time. Based on the results, we have developed a formula with the athletes who can calculate an Ironman triathlon for the first time to calculate their expected competition time. The formula can be found in https://pubmed.ncbi.nlm.nih.gov/24198578/