But what makes a great athlete varies by sport. For example, David Epstein in The Sports Gene had a whole chapter about how great MLB players have just freakishly good visual acuity. Like if the normal rate of 20/5 vision is I dunno 1 in 5,000 normally it's way more common in MLB, and that allows players to hit the ball better. So that's a skill that really doesn't have to do with increased upper body strength, it's visual acuity + brain software.