[soperj]

Lebron played football as well. Most olympic athletes likely played other sports before picking up the sport they're competing in. No one grows up specializing in javelin, discus, shotput, rowing, decathlon etc, etc. There's also all the multi-sport athletes that were phenomenal - Jordan, Gretzky, Bo Jackson, Deion Sanders, Jackie Robinson all come to mind.

[LanceH]

Lebron played football because he's 6'8" 250lbs and a supreme athlete. Being a top notch athlete causes one to play more sports, not the other way around.

[soperj]

Connor McDavid is a top notch athlete who didn't play other sports. Has said he'd be horrible at them.

[anthuman]

I know lebron played football. I'm sure he played some baseball and soccer too.

Everyone you listed specialized in a particular sport. Specializing in a particular sport doesn't mean that's all you do. You can specialize in hockey but also play baseball or basketball for fun, etc. And if you are exceptionally gifted, nothing prevents you from "specializing" in two sports. But the point is that you "specialize".

I wouldn't call Jordan, Gretzky, Sanders or Robinson "phenomenal" "multi-sport" athletes. Jordan wasn't a phenomenal baseball player. Neither was Deion Sanders. I've never heard of gretzky being "phenomenal" outside of hockey. I only know of Robinson from baseball. And Bo Jackson specialized in two sports and he was phenomenal in both.

Once again, you can specialize in a sport and play other sports.