I come from a pretty seriously athletic family. My cousin has a gold medal from the Athens Games. My sister trained with Károlyi. Yesterday, my brother Joe competed in an Ironman.
Here is what an Ironman is: a triathlon, consisting of a 2.4 mile swim, a 112 mile bike, and then a marathon (26.2 mile run.) In a row. Without a break for a nap, or some snacks, or a two week period of recovery between those stages, which I'm guessing would be the minimum for a mere mortal to complete this race. Just one right after the other, as fast as possible.
I remember watching the Hawaii Ironman on television when I was younger, and wondering how people could do something like that. When I was 11 or 12, my swim team had a swim-a-thon, and I swam 2.4 miles, just to see what it was like. Even at a leisurely pace, in the comfortable, controlled environment of a pool, I was exhausted after.
When I write, and I need to put myself in the mind of a character who is fierce, who is determined, who gets up long after she should have fallen down, I think about my brother Joe. He is officially an Ironman, and I am so proud it is ridiculous.