Shawnee Heights' warm up is a ball buster. I have first hand experience. What we do is called flowing, where you do a live takedown on a partner who gives about 30% resistance. Then the partner does a live escape with about the same resistance. Then you switch roles and go again. In practice we would do this sometimes for 20, 30 minutes without stopping. Great for getting in shape and practing takedowns full speed, but not any fun at all.