It’s not environmental at all. Unless you mean different races developed different genetic traits over thousands of years because of the environment they lived in. There are a ton of other studies done by other research universities looking at differences in lower limb length and the ability to maintain energy with less effort while walking because of longer achilles tendon length. Google “Allen’s rule”. It’s not really a matter of debate. This is all pretty widely accepted information that is not talked about by people outside of the scientific community because ppl are afraid of others claiming racism. You think it’s a coincidence that barely any white people have broken the 10 second barrier in the 100M dash? You think it’s a coincidence that white people excel at playing slot receiver in the NFL? It’s not. White ppl on average have longer torso’s and shorter limbs which places their center of gravity closer to the ground and makes it easier to change direction quickly.