Ball exercises are a great way to add some diversity to your workout. Use this exercise to firm up your obliques. Twisting exercises are a great way to get some results in an instant.
Lying on the floor, have your legs extended straight up with the ball between your feet. Arms should be straight out to the sides, head resting on the floor.
Exhale and motion ball with your legs towards your left side. When you reach a couple feet off the floor, inhale, and bring legs back up to center.
Continue with the same motion on the right side. This should be one continual motion without any pauses. Return to center for one complete rep (source).
If you don’t have a ball to use, then try bending your knees and twisting from side to side. To make this exercise even more intense; add weight. You can do this by putting a medicine ball between your feet or between your knees.
(CES, PES, CPT, BS)