It makes sense that they would have different body compositions than swimmers. I think they use their muscles differently than the swimmers. They need muscle strength to launch themselves into the gravity well (
) whereas swimmers don't fight gravity. And they need flexibility and strength to contort and throw themselves into the diving positions.
I'm gonna have to pay close attention to their expressions this time when I watch the Olympics. I wonder if they're screwed up (faces) in anticipation of hitting the water, or just intense concentration, or what.