To make a post that's on topic and not part of the war here....
From what I know, some cultures (not entire races, just cultures) have significant physical differences when brought to the level of atheletes. It has to do with the way they used their muscles and what they needed to achieve to survive over the years.
In terms of sports in America:
Basketball has an overwhelming number of blacks. In part that's because many are brought up to embrace sports and try to make it, believing there is no other way for them to escape crummy jobs. But what's interesting is why it's only basketball. Basketball is the EASIEST to practice. All you need is a ball, a hoop nearby and a few others to play against to practice. It's that simple. The three other major sports in this country require a lot more in terms of money and people.
Football looks normal to me. The ratio may not be correct when it comes down to the percentages of white/black/asian/hispanic in the USA, but it's a decently diverse sport.
Baseball encompasses the globe. There are players from Japan, South Korea, the Dominican, Puerto Rico, Cuba, America, Canada, Mexico, and beyond playing Major Leage Baseball. The only area of baseball that has been dominated by any race historically is pitching, and it's mainly white guys. Hitting is as diverse as you can get. There are superstars of all races.
Hockey is... white. As white as fresh snow. Hockey is also played in colder climates and requires financial investment, which means HISTORICALLY it makes sense why it's basically all white guys.
As for physical dominance, I don't see any race being clearly more dominant than the others when you get down to it.