Well alright then.
I practice by looking for something around me to hit them with first. We also discussed this in another thread. I think a better use of my time is to take stock of where I am and assess what I can use as an improvised weapon in order to beat the tar out of someone. At 240 pounds, when I hit someone with a chair, even a 20th level Sohon Ninja grandmaster is going to lose a lot of his ability to fight. Same goes for a textbook, a backpack, or my water bottle.
What I don't do is try to figure out how to defeat each style of attack. Instead, I know that I can pick my moments and hit someone in the head really hard with a dense, blunt instrument. If you teach your students to do the same, you will probably increase their chance of success.
Kent