Lifting the feet off the ground forces the abs to work more. You will feel this in the lower part of your abs, too.
- Sit on the floor with your knees bent. Pull your abs to your spine and lean back a few inches while lifting your feet off the floor. Be sure to keep your back straight.
- Reach your arms out in front of you and twist your torso to the right, then to the left, to complete one rep/rotation.
- Start with 12 to 15 reps per set.