Lie flat on the floor with your lower back pressed to the ground. For this exercise, you will need to put your hands behind your head, with your neck cradled in your hands. Always be careful not to pull your neck during these exercises, rather, rest your head and neck in your hands. During this exercise, you will create a bicycling motion with your legs, first, bringing your left knee up as you also elevate your right shoulder off the floor toward that left knee. Contract your oblique muscles at the top, and then repeat by bringing your right knee toward your left shoulder. Repeat this in a bicycling motion. A rotation on both sides is one repetition. Continue alternating in this manner until all of the recommended repetitions for each side have been completed.
Take it slowly at first. It is most important not to tweak your neck forward, and instead to focus on working the abdominal muscles. Also remember to breathe in during the eccentric (lowering) part of the exercise and to breathe out during the concentric (upward) part of the exercise.