Now, I'm going to demonstrate how to do a figure 8 crunch. What we're going to do is use a light medicine ball to do this exercise. I'm going to place this medicine ball securely in between my knees, just like so. Hands at your side. Lift the legs up about 90 degrees, and I'm going to move my hips in a figure 8 motion.
It's a little bit more of an advanced abdominal exercise, taking some practice to get used to. You keep your adductors tight, so it keeps that ball securely in the middle of the knees, and if you want to make the exercise a little bit more difficult, you transfer your hands from the ground to behind your head, staying up in that crunch position. You're moving your legs in a figure 8 motion. You want to try to practice these. Do high repetitions so you can get the form down. That is the proper forms to do a figure 8 crunch.