I'm very proud of my recent innovation: When I do a crunch, I triangle my legs. Next crunch, I triangle them the opposite way. It makes the crunches harder and helps you practice the triangle choke movement. I also do upas, shrimping, etc. Also, I practice lifting my heavy bag as if I'm lifting an opponent from double underhooks. This helps develope motor skills and functional strength. Another thing I do is hand my heavy bag low, so it's about a foot off the ground. I shoot in just like I would against an opponent, drive through, and lift the bag. I'm interested to hear what others do.