How to do Crunches

1. Flex the neck to move the chin to the chest by contracting the abdominal muscles and oblique muscles. Begin by pulling the rib cage up and over the pelvis.
2. While keeping the lower back flat, continue to pull the rib cage up and over the pelvis.
3. Slowly allow the trunk to uncurl then the neck to extend back to the starting position, while maintaining tension in the abdominal muscles.