Although the Ironman Championship for women has been organized already 42 times and 123 medals have been given, there has been only 52 distinct athletes that were on the podium throughout all the competitions.
Isn't that interesting?
Let's look at the story behind it.
Let's look at all the medalists and years when they participated. The athletes are sorted chronogically, according to their first appearance on the Ironman podium. Colored square means that an athlete won a gold/silver/bronze medal in that year.
It is immediately visible that some athletes are much more successful than the others. When they enter a competition, they keep on winning medals for a couple of years in a row. Let's mark the ones who won 4 or more medals.
Now, if you look closer at the multi-medalist athletes, you will notice something peculiar: sometimes they had a one- or two-year break in a medal streak and afterwards reappeared on the podium. They could have had a worse year, but why would so many exceptional athletes systematically have really bad years, only to continue winning afterwards?
There is one very probable reason for this. For a long time the participation in the Ironman competition used to be determined by the lottery. This means that some perfectly prepared athletes simply did not have a chance to participate at all, therefore someone else could win the medal they would have gotten otherwise.
This makes Ironman a very peculiar competition: one demanding extreme physical fitness, but also one where the results are strongly influenced by a random chance. May the best win—but only among those who had enough luck to participate.