Muscle Groups

Crunches are a classic core exercise that are commonly used in fitness programs. They target the rectus abdominis, which is the muscle that runs vertically down the center of your stomach. To perform a crunch, lie flat on your back with your knees bent and your feet flat on the ground. Place your hands behind your head or across your chest, and contract your abs to lift your shoulders off the ground. Exhale as you lift up, and inhale as you lower back down. Be sure to keep your chin tucked and avoid pulling your head forward with your hands. You should feel the burn in your abs as you perform each repetition.