Reverse Crunch

The reverse crunch is proven as an effective lower abdominal exercise once executed correctly. It will take a few attempts to get the movement right and to get sufficient distance from your lower body and the mat.

Movement:
Lie on your back on the floor with your legs extended in the air directly above your hips and your hands under your hips. Initiate the movement from your lower abs and curl your hips up off the floor and ‘slightly’ towards your head. Hold at the top of the movement for a second and reverse the motion slowly to the starting position and repeat. Do 10 - 15 reps.

Do not get discouraged if you are not able to lift your hips to an adequate height at first. Keep practicing this exercise and not only will you be able to execute it correctly but you will see the added benefits of a firmer and stronger lower abdominal region.

Pic from bodybuilding.com