Team USA swimmer Michael Phelps kept his face smooth for the races in Beijing, but the photo on his bio at NBC Sports shows some unmistakable, edge-carved, "designer" stubble on his chin. Also, Team Australia swimmer Andrew Lauterstein showed unshaped stubble in at least one of his races (I don't know how long those hyperlinks will last).
I don't know whether short stubble physically affects a man's swimming speed enough to matter in races. I can, however, imagine some sort of psychological effect on each swimmer's own self ("I just want to look a certain way today in order to feel faster.").


