Black athletes perform better on the running track, and whites in the swimming pool, because of their belly buttons, according to a new study in the International Journal of Design and Nature and Ecodynamics. The shape of the belly button isn’t the issue; rather, it’s where it’s positioned relative to the rest of the body, AFP reports. As the centre of gravity for the body, its position is more important than total height, according to lead author Andre Bejan of Duke University. “It so happens that in the architecture of the human body of West African-origin runners, the center of gravity is significantly higher than in runners of European origin,” giving them an advantage in track sprints, he said, as black athletes therefor have a “hidden height” three percent greater than whites, giving them a speed advantage. Meanwhile, in the pool, those with longer torsos have an advantage.