As I've previously stated, bare knuckle rules karate is one of the roughest forms of competition. Sure, they don't allow punching to the face in this type of sport, but because of that, a lot more pounding of the body at close range takes place. The hard body punches, low kicks, and knees and having to fight more than one bout to win a tournament takes it's toll. Here's a great clip of the 5th Karate World Cup Lightweight Final. You will appreciate this kind of combat.