This question has totally gone off target. This definitely has nothing to do with homosexuality or masculinity. I started shaving (trimming) my legs long before (early high school) I even knew what being a man really meant and additionally I am not gay. Look across the world of athletics and you'll find men shaving body parts. Some for athletic benefit, some simply to show their finite muscle definition. But why distance runners? And when did this start? I'm guessing no runners before the 80's shaved and I don't think there's a high percentage of runners who shave, but at the competitive level it's higher than 5%. Just look around your next road race or collegiate/pro track race. Google some pics of Rtiz. There are shavers out there. (Though I doubt Al Sal shaved, Pre. Never!, Paavo Nurmi. Not a chance!)
The mystery remains unsolved!!!