Crunches are some of the simplest, most effective exercises that can be performed to tone and tighten the muscles of the abdominal, or core, region. Attention to form is key in executing these exercises to achieve maximum benefit and avoid injury.
Crunches target the following abdominal muscles:
• Rectus abdominus, which is the central panel of muscles known as the "six-pack," running from the bottom of the sternum to the pubic crest
• Internal and external obliques, which comprise the muscles on the sides of the abdomen
• Transverse abdominus, which is the deepest layer of abdominal muscle and runs from the inside of the hip to the rib cage and connects to the diaphragm
Adding crunches to an exercise routine is a good way to help improve core strength. "Core strength" refers to the fitness of the collective muscles that are found in the abdomen, the lower back, and the pelvic floor. These muscles assist in everyday activities such as standing, sitting, bending over, and lifting. A strong, stable core means you will be able to function better in daily tasks, have improved balance, and be less prone to low back pain and injury due to inflexibility and weakness.
To perform effective crunches one must :
1. Lie on one's back on an exercise mat or carpeted surface. Bend the knees and place feet flat on the floor.
2. Place hands where they feel most comfortable — suggested positions are either crossed on the chest or balled into loose fists clasped on the sides of the head. Do not clasp the hands behind the neck, as this can create a tendency to pull up on the neck as the crunches are performed.
3. To execute the crunch: Contract the abdominal muscles to pull the head and chest up toward the knees, simultaneously pushing the lower back down into the floor. Keep the chin up and off the chest. Do not come all the way to sitting but lift the shoulders only a few inches off the floor.
4. Hold this position for at least three seconds at the top of the crunch. It is important to not hold one's breath. Be mindful about the muscles that are being worked — concentrate on squeezing the abdominal muscles.
5. When the hold is released, do not just immediately relax the abdominal muscles and fall back to the ground. Release the position slowly, gradually lowering the shoulders in a controlled manner. Breathe deeply and consistently.
6. Do as many crunches as possible while preserving form and keeping the motion smooth.