For one thing, that is highly dependent on the sport you are talking about, if you mean triathalon, marathon running, and basketball, you're right.
Except for one thing, the skill level of blacks in Basketball is cultural, whereas triathalon and marathon running scientifically is better fitted for black people's anatomy and abilities.
As a White person, I might of played an actual game of basketball about 10 times in my life and im 27 years old, blacks play basketball MUCH, MUCH, MUCH more.
Whereas I played little league baseball when I was a kid.
White people are better weightlifters, better defensive linemen in football, better swimmers, better baseball players, better soccer players, better hockey players.
But this also has brings about evolution, Black people knowing that they cannot with whites in those sports, are going to train harder IF they want to play, so the blacks would pull off an occasional grandstanding performance there too, which is why I actually expect the Jamaican Bobsled team to do pretty good this year.
Also, the USA doesn't play sports at home, the same way as other countries do, other countries predominantly play the sports you see in the Olympics that are true tests of a person's physical ability, and they are paid nowhere near as well as American home grown professional athletes who play purely Americanism in sports such as the NFL.
In Europe, you could be a cook, or a store clerk, and live next door to a professional bobsledder, snowboarder, or soccer player based on pay all except for in Italy.
Sports in the USA, is also an outlet for success in the American underclass, White people having the highest educational achievement, and the second highest pay after Asians, and also White people being the majority in the USA have no absolute NEED to be involved in sports in order to be a success in life either in monetary wealth, or in achievement, so what you end up with is the American underclass playing the sports on those merits.
This is supported by multiple athletic doctors, scientists and sociologists, and economists.
So black people actually dominating sports, is an American myth.
America wins most of the gold medals on diversity which includes whites, not on Black Athletes.