UFC welterweight champ Georges St. Pierre used gymnastics in preparing for his last fight, a unanimous decision win over Jake Shields. He picked up much of the body control, strength and flexibility that comes with mastering gymnastics, but he can't do everything they can do. For example:
GSP knows that even he can't do a planche push-up. Nick Diaz, his opponent this fall, also cross trains. He recently completed a triathlon. Perhaps if their bout goes to a draw, the two can do an old-school Olympic day competition to decide who will be the UFC champ.