it's statistically wrong. i was male all the way through high school; it wouldn't have been hard to find a female that could beat me at arm wrestling. the reality is that neither physical strength nor athletic ability distribute along gender lines. so, you're setting up a demonstrably false sexist premise and then using it to argue for a demonstrably false sexist outcome.

that said, what that actually implies is that athletics shouldn't be gendered in the first place.

to be clear: you won't find any convincing evidence that boys can necessarily run a track faster than girls. that's not something that's actually upheld by evidence. it's just a boneheaded, sexist assumption.