A Tennis ball hit directly at you hurling at your leg would hurt like a bitch. It's probably the closest to a fairly strong punch, but not much more.
Yeah, I'm kinda pissy about how CLANNAD is turning out right now. Nagisa's route was the most boring, yet because she occupies the position as the "lead" girl, she gets more attention than the other girls. Shit, some of the other arcs (Tomoyo, Kyou, etc) are fucking AMAZING. Why can't they do them right?