Only one white athlete, the Frenchman Christophe Lemaitre, has ever run a sub-twenty second 200 meters and black athletes have dominated many Olympic events, especially those from the USA, Britain and the Caribbean nations although, curiously, they are noticeably absent from swimming events.
The theory is that this is the result of a Darwinian evolutionary process caused by the slave trade. Almost all the African slaves which were taken to the new world came from West Africa and were selected from amongst the fittest because these commanded the highest prices and were most likely to survive the appallingly inhumane conditions in the slave ships.
So, in addition to fittest being selected initially, another selection occurred on the slave ships, with only the exceptionally fit surviving the journey to the New World.
Then another selection process occurred on the plantations where the work was hard and physical and, with slaves being cheap and disposable, those who failed to work hard enough were simply killed and replaced by more bought from the next slave ship to dock. And of course, a wise slave owner encouraged his fittest (i.e. hardest working and most productive) slaves to breed, just as a herdsman breeds from his best stock.
And so the slave trade produced an intense Darwinian selection for fitness from which today's population of African Americans, Caribbean Islanders and Britain's Afro-Caribbean population is descended. It's not surprising therefore that they contribute disproportionately to the sporting success of their respective nations.
It's ironic that they tend to subscribe disproportionately to a religious superstition which teach that Darwinian Evolution by Natural Selection doesn't happen. A religion moreover which slaves were originally forced to adopt because it made them easier to control by accepting a place allotted them by the slavers' deity, using scriptures in the slavers' Bible, and so less likely to use their superior fitness against the slave traders and the slave owners, who of course had all the guns, dogs and instruments of torture and execution, the better to ensure obedience and adherence to the 'faith'.
A 'faith' which sold them the lie that accepting your place without complaint in this world would ensure freedom and happiness after death (when they were no longer any use and couldn't complain) and which, in some countries, is still being used to give false hope when all real hope is being denied by those who still depend for their wealth on a supply of cheap, compliant and passive labour who humbly accept their place as allotted by a 'white' god.