Execution
Place a small to medium size stability ball on the floor and kneel next to it with your body facing the ball. With your stomach positioned on the ball and keeping hands in contact with the floor, very slowly begin walking forward using your hands, until your feet leave the floor and shins are resting on the ball, wrists under your shoulders. Once in this position it will resemble a push-up, although the legs will be elevated by the ball rather than in contact with the floor. Maintain a rigid torso and do not allow sagging of the low back. Engaging the abdominals throughout the repetition will help to keep the back in its proper alignment. (See photo 1.)
Next, slowly begin bending your knees, bringing them toward your chest. Your upper body should not move. This will require you to focus on keeping your balance as the stability ball rolls toward you. (See photo 2.)
Finish. Stop at the point where you have pulled your knees in to their furthest, hold briefly and then return to starting position.
Advanced: Perform the exercise as shown, but continue tucking the knees until they are under your torso and then lift the hips upward toward the ceiling. This position will resemble a partial handstand, with the arms straight and wrists directly under shoulders.
The most challenging part of the stability ball knee tuck is maintaining balance on the ball as your body is moving. For safety, at least until you have mastered the exercise, do not attempt to perform knee tucks unless you have a spotter. Individuals with medical conditions or joint problems should check with their doctor before attempting any new exercise.
Begin with one to three sets of knee tucks. This exercise can be performed every other day, completing as many repetitions with each set as you are able without deviating from proper form.
Tip
Just as with any other muscle group, it is not necessary to work the abdominals every day. Instead, focus on totally fatiguing the muscles on the days that you do work them, and then allow the following day for rest and recovery.
About the Author