Would You Make A Good Ironman?

Scientists noted the common features in the best Ironman racers.

Photo: Thierry Sourbier

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 Are there variables that can predict an athlete’s success at long-course triathlon? Scientists in Switzerland say yes. In a review of 76 studies on Ironman triathletes, researchers noted common themes in determining a successful outcome at the 140.6 distance.


On average, the age of a best Ironman triathlon performance was between 30 and 35 years for both male and female athletes. Don’t fret about aging—studies also show the average age of peak performance is increasing every year.

Body type

Lower body mass and lower body fat are associated with both a faster Ironman race and a faster run split. As for shape, slender body structures tend to fare better than stocky ones.


Faster finishers (those under 10 hours and 30 minutes) tend to average greater training volumes than slower finishers. On average, the faster men and women trained approximately 14 hours per week, broken down into 2.5 hours of swimming, 7.5 hours of cycling and 4 hours of running.


Slow down to go fast! A lower intensity during training was associated with faster race times. A significant correlation was established between time spent training in Zone 1 and race success.


Race yourself into shape! The number of completed previous triathlon races is highly predictive for a fast Ironman race time. Consistently, faster athletes have completed more races (of any distance) than their slower counterparts.


Want an Ironman PR? Work on your shorter distances. Standalone marathons and Olympic-distance triathlons have little in common, yet they both influence an Ironman finishing time. Working with a database of marathon and Olympic PR’s, researchers determined a formula for determining a person’s likely finishing time in an Ironman:

MEN: Ironman race time (minutes) = 152.1 minutes + 1.964 × personal best time in Olympic-distance triathlon (minutes) + 1.332 × personal best time in a marathon (minutes)

WOMEN: Ironman race time (minutes) = 186.3 minutes + 1.595 × personal best time in Olympic-distance triathlon (minutes) + 1.318 × personal best time in a marathon (minutes)

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