When I was in high school, Charlie, who lived on the same floor of the dorm as I did, shaved every single hair off of his body in order to compete in the state swimming finals. And I do mean every. single. hair.
He won state champ in the 100m breast stroke, and it was indeed his fastest time ever, so apparently it worked.
Personally, I would not want to put up with the itching that would result from the hair growing back in. In the summer. And he lived in South Carolina at the time. Charleston, where it gets God-awful hot. Ugh. I shudder even thinking about it.