Given that racists and slavers used the “natural physical strength” of black people to justify putting them on hard labor and some medics still think that blacks has higher resistance to pain, I wonder if when black athletes started to join mixed race sport teams, some racist would have used the same “biological advantage” argument that now transphobes use against trans athletes to claim it was “unfair” for black to compete against whites to justify segregation.
The famous example you’re thinking of is Jimmy Snyder, aka Jimmy the Greek, a sports commentator and sports betting expert who used to work for CBS sports. He was interviewed as part of a series about civil rights in the US, and the interviewer was sort of expecting him to say something pleasant about black folks’ success in athletics opening doors for education and leadership, etc.
Instead he made some pretty astonishing claims that were intensely racist.