The Purpose Of Abdominal Crunch Exercises

The abdominal crunch is considered a "core strengthening" exercise, because it strengthens the base, or core, sets of abdominal and back muscles that promote good posture and minimize the risk of injury, says Matthew McDonald, author of "Your Body: The Missing Manual." Crunch exercises are safer than situps for your back, and they are recommended for beginners who are just starting an abdominal exercise regimen.

Benefits

Crunches work the muscles in the "core" of the body --- the pelvic, lower back, hip and abdominal muscles. Strengthening your core improves balance and stability, increases endurance, improves posture and makes performing physical activity easier. Crunches are relatively easy to do compared to other similar exercises, and they require no extra equipment. Strengthening your core with crunches can help you avoid injury and lower back pain if done properly.

Risks

The biggest risk involved in performing crunches is the possibility of stressing the back. This is usually caused by doing too many crunches or by improper form when performing the crunch. According to McDonald, you should work your way up to doing no more than two to three sets of 25 repetitions in each set per day, focusing on form. Another problem arises if you only do crunches to strengthen the abdominals. You could cause your stomach to become abnormally distended instead of flat, according to Ashley Neglia of the American Council on Exercise.

Expert Opinion

Studies have shown mixed results with regard to the effectiveness of crunches when compared to other exercises and abdominal exercise equipment. A study published in the 1997 "Journal of Sport Rehabilitation" found that the crunch was more effective in activating the abdominal muscles than all but one of five abdominal exercise machines, and the crunch was more effective than doing situps in activating the primary muscles of the abdomen -- the obliques and the rectus abdominis. However, a 2001 study sponsored by the American Council on Exercise found that the traditional crunch ranked 11th out of 13 exercises that worked the abdominal muscles. Other variations of the crunch -- including the exercise ball crunch, vertical leg crunch and reverse crunch -- finished in the top five.

Recommendations

Crunches can be included as part of a total fitness routine, but additional exercises that work the core muscles should be included. Exercises such as pushups, planks and side bridges can help strengthen your core muscles, along with the captain's chair and pelvic tilts and lifts. Include variations of the traditional crunch to increase the effectiveness. Consult with a qualified fitness expert to learn how to do these exercises properly.