This disparity in athletic achievement, obvious to Olympic viewers, throws up so many sensitive questions of race and human difference that it is rarely discussed in public.
But now two US academics have risked controversy by publishing a theory that attempts to explain the contrasting performance of black and white athletes using the laws of locomotion.
They argue that black sprinters have a 0.15 second advantage over their white rivals because they tend to have a higher center of gravity, meaning they can fall to the ground more quickly between each stride.
Conversely, having a lower then average center of gravity helps white swimmers because their speed is determined by the height they can get above water.
More of their upper bodies are above the waterline, so they can generate and ride larger waves.
Adrian Bejan, a professor of mechanical engineering at Duke University in North Carolina, and Dr Edward Jones of Howard University in Washington, used existing data on the body dimensions of soldiers of various nationalities to determine that black people – or more precisely those of West African origin – have a centre of gravity three per cent higher than white people.
Prof Bejan said the theory “completely accounts” for the increasing racial segregation of Olympic podiums.
The last 25 men’s 100m sprint world record holders have been black, while white swimmers have held the 100m freestyle world record since 1922.
Previous attempts to explain sporting achievement along racial lines have fallen down on the success of East African long-distance runners, and the researchers concede that their theories of locomotion do not cover endurance events, only sports in which the goal is to achieve maximum possible speed.
The research is published in the peer-reviewed International Journal of Design and Nature.