Instead of: Reverse Crunches Try: Hip Lift and Twist
This amped up version of reverse crunches forces your abs to do double duty, lifting your hips and directing the movement of your pelvis.
To do it:Lie faceup on the floor with your palms facing down. Extend both legs as straight as you can up towards the ceiling. Brace your abs in tight and raise your hips and lower back off the floor. As you lower, turn your hips to the left, lowering your pelvis down and to the left. Repeat the hip lift, returning your hips back to center as you lift, and then lower down to the right this time. That's one rep. Work up to 3 sets of 15 reps.