I'm confused w/ whether or not I want to or not want to maintain contact w/ something when I strike it to get the most affect. For example they say when you're hitting a baseball or a golf ball to maintain contact as long as possible (the 'follow through') to drive it as far as you can. However, when trying to karate chop boards in half or trying to knock-out somebody w/ a punch they say to minimize the contact time. Both are based on Force*time=change in momentum. It seems like the 2 contact time applications are contradictory where am I going wrong?