If it's possible to admire Chrissie Wellington any more than we already do, I would argue that her decision to retire from Ironman competitions is a very persuasive reason to do so.
Have a read of the recent interview she gave on the Ironman website and then come back here.
It takes a lot of guts to be able to say to yourself "I've proved that I can do this; now it's time to do something else" - even more guts, I would say, than it takes to be an Ironman World Champion in the first place. I think many of us who compete in Marathons and Ironmans do so because they are alternative realities with clearly defined goals that can be objectively measured - recognizable successes that no-one can take away from us - unlike the scenarios which arise in a typical job, in which not everyone might agree as to how well we have performed. To go from this level of recognition with the structure that following the accompanying training programme must provide, to taking on a new challenge which hasn't even been completely formed yet must take a tremendous amount of courage.
It would surely be so much easier for Chrissie to keep soldiering on until someone younger or fitter eventually knocked her off her pedestal. Then she would gracefully retire in the time honoured fashion with a pat on the back and a BBC Sports Personality of the Year Award, with everyone satisfied that she had given her all to the sport. But I think Chrissie knows that if she can take on and conquer the Ironman, then she can do pretty much anything she puts her mind to. Now she has a platform from which she can do many of the things she talked of doing in her autobiography, picking up from where she left off before her stint as an Ironman World Champion. It's clear to me that Chrissie has never seen the Ironman as an alternative reality but as a step forward in her own personal reality.
Another aspect is that you can be motivated by impressing other people or you can be motivated by impressing yourself which is usually a much harder thing to do because only you know what you are really capable of. Chrissie defines as her "perfect race", her victory in Kona in 2011. While others would have dwelled on the imperfection stemming from injuries sustained in her recent bike crash, this was the time she had to dig the deepest in order to win. For me, what impresses me most is her ability to avoid being drawn into that trap of always going for one more. Sports commentators are for ever thinking of records that will be broken if only a certain number of consecutive titles can be won or a particular time can be beaten, but where does it all end? She must have a tremendous strength of character to be able to say "enough is enough" when everyone around her (except, perhaps, her boyfriend) is egging her on.
I initially thought of writing that "Chrissie is the World Champion Ironman and the World Champion of Quitting While You Are Ahead" but somehow the word "quitting" doesn't sit well in the same sentence. Chrissie isn't quitting, she is starting a new challenge and I for one am interested to see what she does next. I'm sure it will be impressive and not necessarily have anything to do with swimming, running or cycling.