Different genes
One thing you'll notice about the naturally athletic is that they all seem to be born with a certain grace, the ability to walk with lithe steps and catch a foul ball in the stands.
One thing you'll notice about leaders is that they're not naturally born. They don't have much in common on the surface, other than the fact that they are leaders.
This is bad news is you've got the wrong genes but want to throw the shotput, but great news if you'd like to be a leader. It's a choice, not the way you were born.