African Americans dominance in Sports

What really is the sole reason for African Americans dominance in sport today, and 10, 20 even 50 years ago in the past. People have researched and researched to find the answer, because obviously it's prominent in what we see in sports today. Mostly dominated by African Americans in sports like football, basketball, and track. In class we discussed this and tried to determine whether it's genetics that make African Americans run faster, jump higher and over power their opposition. Or, is it just hard work? Now, are there genetic differences that make up every individual? Yes of course. Are the genetic characteristic related to athletic excellence? Yes, you say that. But would you say that genetic make up and pure talent is the sole reason for African American dominance in sports? I'd have to say no, because bottom line, as everyone knows, talent beats hard work. It's that simple, and African Americans have had that mentality of "started from the bottom, now we're here." Where African American faced a segregate sports system and were very limited in sports they could participate in. So that brought out the attitude of wanting it more, proving people wrong, making the non-believers believers. Now don't get me wrong, there obviously is a physical difference between blacks and whites. Blacks have a slight genetic advantage and are more physically suited for activities requiring speed and power, longer levers, slimmer pelvis, and less fat onmuscle, but that doesn't count for the want and the will and the determination for black people to strive to be better then their white counterparts. So with this mentality it's left us with some of the worlds most gifted and decorated black athletes that have left such an impact of the world that now there's no telling how far African Americans go, because now, the skies are the limit.
In the link below is a 7 minute clip on the early ages of African Americans in sport and their impact

http://www.youtube.com/watch?v=tSMnFr_rhN0