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.
It’s a funny story, I just don’t know why you give it any credibility given how many highly improbable things have to be true. It’s far more likely that it was a story told solely for humourous reasons, or it was a minor fib that became more humourous over time.