"What's important is not whether an athlete has an innie or an outie but where his or her navel is in relation to the rest of the body, says the study published in the International Journal of Design and Nature and Ecodynamics
"The navel is the center of gravity of the body, and given two runners or swimmers of the same height, one black and one white, "what matters is not total height but the position of the belly button, or center of gravity," Duke University professor Andre Bejan, the lead author of the study, told AFP.
"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," which puts them at an advantage in sprints on the track, he said.
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In the pool, meanwhile, whites have the advantage because they have longer torsos, making their belly buttons lower in the general scheme of body architecture."
http://news.discovery.com/human/belly-buttons-sports-athletes.html