It’s true, but some people go way too far with it. All it means is that people of West African descent tend to have more fast twitch muscle fibers. You could be white as sour cream and get lucky with your genetics and end up the same way. It’s having those muscle fibers that’s the advantage, not having west african heritage. In sports like basketball or sprinting where fast twitch fibers are a big advantage, you tend to see populations of people who are predisposed to that getting over-represented.