However I believe that most world class athletes use performance enhancing drugs to achieve world class status. But differences in physiology clearly make a difference to the performance of individual athletes. The question is, is this consistent across population groups. There is no doubt that hard work without the right physiology cannot make a champion. But right physiology without hard work will be as much a hindrance.
Race is a confusing term politically and sociologically.
It is also meaningless according to mainstream biology and genetics. The key here is that West Africans and East Africans are very different, yet they are defined as belonging to the same race. Remove race from the question and it's a much easier conundrum to deal with. That is not to say that all black men are faster than white men but that the average black man has more chance of being a top athlete than the average white man. This could come from having faster twitch muscles or a more responsive cardiovascular system.