Now, I'm going to demonstrate how to do a one-sided crunch. So, what you're going to do is lie down. Cross the one leg over top of the right knee. Okay. Hands behind the head. Lightly on the back of the head, so you don't pull the neck. And you are actually going to come up and turn that right elbow into the left knee. So, the important thing to remember is don't bring the leg toward you. Keep the leg stagnant. And exhale as you come up as you reach from that right elbow to that left knee. You're going to switch sides. Do about 15-20 each side. Notice, I do not bring my right knee towards me. I just keep it there. No movement. That way your upper abdominals are doing all the work. And even the obliques as you turn that elbow slightly. Exhale as you come up holding that position for one or two seconds. And that is how you do a one-sided crunch.