The workout ball knee tuck is great for anyone looking for a challenging abdominal exercise. You might see this version of the tuck referred to as the "tuck and roll" or "knee-in." Some refer to it as the "pike." However, this is not accurate. The knee tuck is different from a pike.

Performing this exercise requires a great deal of upper body strength. Thus, it may be difficult for some. Also, whenever the knees move toward the chest, the hip flexors are involved. So any form of knee-to-chest exercise will invariably require use of the muscles that act on the hip.

Start by walking your body forward on the ball with your hands. Roll out until the ball is on the shins. The upper body should be in the push-up position. Next, roll the ball by bringing your knees toward your chest. Be sure to exhale as you contract the abs. Return to the starting position and repeat the exercise.