In a full verticle crunch, you really work the abs by involving both the upper and lower body. To do it right:

1. Lie on your back and extend the legs up towards the ceiling.
2. Place hands behind your head (lightly cupping it) and contract the abs to lift the shoulder blades off the floor.
3. At the same time, press the heels towards the ceiling, creating a ‘u’ shape with the torso.
4. Lower down and repeat for 12-16 reps.

Related posts:

1. Reverse Crunch For Abs
2. Plank Exercise on Elbows and Toes For Abs
3. Long Arm Crunch For Abs
4. Exercise Ball Crunch For Abs
5. Crossover Crunch – Abdominal Exercise