I guess defining what a sport is and isn't would be a whole other deiscussion.
If we lose the term loosely and look at what is covered at sports, please explain dominate?
If you look at the Top 200 players in Golf, what percent is black?
While I am no big fan of soccer, it is dominated by white guys overall.
Hockey dominated by white guys.
Baseball - dominated by white guys, second comes hispanics, third is black guys.
Basketball - Let's not forget the NBA MVP for the last 2 years was Steve Nash. The top three vote getters this year were Nash, Wade, and Novitzki - Two of them are white. The majority of basketball teams are black when you look at % of each race. Although, this is changing quickly because of the emergence of the International players. Let's not forget the reigning world champs in international play in basketball is a team that beat the USA with a team predominantly white.
Football - this would be hard to say it is dominated by black players. I look at football as a true team sport and coaching has so much to do with it. What % of black head coaches are there? What % of starting QB's are black? Both of these numbers are growing, but still small compared to white guys. 99% of the kickers and punters are white. Most teams still have a dominantly white offensive line. In other parts of the game, RB, WR, and defense tend to be black. But overall, hardly dominated by one specific race.
NASCAR - dominated by white guys.
If you go to a bodybuilding show at NPC level both regionally and nationally and look at the top 5 spots of all shows, I think you would find more white people are in those spots than black. Figure and fitness - predominantly white. Women's BB - mostly white.
Strongman - predominantly white.
Powerlifting - predominantly white.
So, first we'd have to define what constitutes a sport and second we'd have to define dominate. At the very top level of bodybuilding right now, yes it is dominated by a black guy.
If you look at the best athletes in the world and somehow could define athlete, I would bet a black person would fill that role - but, sports aren't solely based on athleticism.
Just stuff to think about.