Tip - How to Do Reverse Crunches | LIVESTRONG.COM

Crunches target the rectus abdominis muscle, which is one of four muscles that make up your core. The rectus abdominis muscle runs the entire length of your core. It begins at your chest and extends downward to your pelvis, and it is responsible for the appearance of your six pack. Typically, traditional crunches target the upper portion of the...