Bicycle Ab Crunch
1. Lie on your back with your hands across your chest.
2. Next, with one leg extended a few inches off the ground and the other leg raised and bent at a 90-degree angle, use your stomach muscles to lift and twist your torso as you reach your elbow toward your raised knee.
3. Pause, and then lower your torso slightly, repeating the crunch on the other side.
4. Repeat for your desired number of repetitions.