Bodybuilding came to my mind. People say they don't have good genes (I would say some percentage of professional athletes do have far better genes than anyone

Bodybuilding came to my mind. People say they don't have good genes (I would say some percentage of professional athletes do have far better genes than anyone else, but not most professional or college athletes). However, unless they try lifting weights 4x a week and/or trying to be good at a sport for five years in their early 20's, they will never actually know.