Compare the grip sizes of doubles and singles players.
The mean grip size is higher for............... Well, it is obvious. In fact this whole post is obvious, maybe I should delete it.
Actually I should hijack the thread and drone on about how much of a genius Federer was to win Olympic gold in the doubles playing with a small grip, well, small for doubles. Mariarafael would do the same with Nadal if s/he could.....hey, Nadal is a tennis god as he doesn't even know what grip size he uses so he must be better than Federer ZZZZZZzzzzzzzzzzzz.