You've done well with your links, Thriller. Credit is due. What I will say is that we've gone off slightly tangentially to what earlier posts were claiming. The earlier posts were about selective breeding somehow strengthening the gene pool of African-Americans during the slavery period. We're now on the individual populations of ancestry and genetic "fitness" for certain activities.
I need to clarify something I mentioned earlier. I said the only main difference of Northern Europeans and Africans were build and melanin percentage. This is mostly true to the phenotype. Bringing in muscle fibers goes more into the genotype.
As it applies to Hayward, though, all the links that you provided would suggest that Hayward is incapable of being in the top 1% or so of quickness and speed, and thus how those two are used in the playing of basketball.
To fix a couple things:
First, heavy melanin content is believed to be the root of all human ancestry, meaning that lighter toned skin was the mutation, not the other way around. This was to better absorb the sun rays in climates that had less of it, namely the higher latitude areas.
Second, even European ancestor society was at one point at the tribal level. Chiefdom and State level societies are a more complex structure that is necessary because of higher populations and things like job specialization.
Third, and this will actually help your argument, is that hunting was different in tribal Europe and tribal Africa. I've read some suggestions, hypotheses, and even up to theories, that humans are genetically designed to be one of the best distance runners on Earth. Africans would hunt by chasing prey until the prey fatigued. In Europe, it's more about patience and quick strikes.
Fourth, both Europeans and Africans ran the gamut as far as people being nomadic, shepherds, or farmers. Animal and plant domestication just happened later in the Earth's timeline in Africa.
Fifth, both Africans and Europeans developed various immunities to diseases. Kind of obvious that those with immunities would be selected in.
Sixth, what a lot of people don't seem to realize is that it's not just the outside environment that affects the evolutionary process. Many traits that have no business existing in the environment that trait exists in. I believe sexual attractiveness is much more important to the passing of a trait overall than environmental affinity. Who cares if that trait survives if you can't pass that gene off because no one wants to do the dirty with you. Now these two thoughts often work together and coexist, but they're not mutually inclusive of each other.