Doing these plank leg-lifts on an exercise ball further challenges your balance to help strengthen your core while you work your backside.
- Lie on your belly on an exercise ball, and walk your hands out so the ball is underneath your shins. Your hands should be underneath your shoulders.
- Draw your navel toward your spine to engage your abs, which will help keep your spine straight and your body stabilized.
- Lift your right leg into the air, then slowly lower it back toward the ball, but don't let it touch. This counts as one repetition. Be sure to keep your pelvis level throughout your reps.