Do Black people dominate sports because of Slavery?

Ok a lot of people say Blacks dominate sports. It's been said in comedies and all that other stuff. Tina Fey said it last saturday on SNL. She said something similar to "If white guys can keep up with black guys in this game then it's not a sport" regarding tiger woods and how its mostly a white sport. Now i hear this a lot and its now coming together that It does seem like black people dominate in sports. My theory is that it was because during slavery blacks were thoroughbred with the strongest woman and strongest man a lot in order to have stronger slave babies. Is this a fair statement?