system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are Africans (specifically Kenyans & Ethiopians) so much faster than everyone else?

I'm just curious.
gpt
I think you're conflating marathon wins with speed. Those nations produce a lot of marathon winners because their people have to cross distances on foot and because of the elevation, which makes their cardiovascular abilities better.