Ah, the worst example of the horrible confluence of racism, eugenics, and sport. For years this was thought and openly implemented in the NFL and European soccer. Football coaches believed that black players weren't smart enough to be quarterbacks, and soccer scouts thought that black (particuarily African) players didn't have the "footballing brain" required of top-flight professionals, and instead valued blonde-haired Scandinavian players higher. Thank goodness for Warren Moon and Pele. Do we really have to debunk this one for you?
Black athletes lack intelligence so they rely on their superior athleticism to get an edge.