Every person I meet that likes to pvp and run after people always have knockback II on their swords while their chasing them or something. I notice that they don't really run away and their the people who chase other people and kill them. So the thing that I don't get is that when they are both running and the person hits the chaser with the sword...they go flying because it was a critical attack with knockback making them harder to chase because they are farther. Although knockback is bad for to the death pvp and chasing...the good part for knockback is that you can cornor a guy to a cornor(when he's not running), and defend your base or get away from someone or away from creepers.