Do you NEED all those expensive ab machines to build a six pack? Not so, according to the researchers at Occidental College in Los Angeles. Properly performed unassisted crunches can be the better choice to build a stomach. When subjects performed four different abdominal movements with and without specialty equipment, commercial devices did not prove to be any more beneficial than manual crunches. You can also engage more stabilizing muscles while executing the exercise. The bottom line: if machines motivate you to train your abs - go for it! But if you don't have any devices available, the resistance of your body weight against gravity can do the magic for your six pack.

Anatomy of the Six-Pack

The abdominals connect your pubic bone to your breast bone, pulling the pelvis and rib cage together during contraction while rounding the back. Psoas major originates in the vertebrae of the lower back and inserts into the top of the thigh bone. Full sit-ups put a lot of stress on your lumbar spine. Think about it – you are lifting your entire torso towards your thighs by force of a small psoas muscle. Most people do not realize that having muscle is not the same thing as being strong. Maximal force exertion is a skilled action where many muscles must be appropriately activated. This coordinated activation of many muscle groups is called intermuscular coordination. Neck support provided by ab training machines creates an unhealthy strength imbalance between the abdominals and the neck muscle, which is often overlooked.

Upper vs. Lower Abs

Lower and upper abs comrise one muscle – Rectus Abdominus. You cannot wishfully divide it into two parts, just like you can't horizontally slice your quads halfway between your hip bone and your knees. It is impossible to selectively develop a part of a single muscle because the main control center is not in the individual muscles or their parts, but is found in the brain. Muscle fibers are evenly spread through the muscle, connected into motor units and controlled by motor nerves in the brain. Even if you manage to recruit a different motor unit with a different exercise, its fibers will still be all over muscle. So no matter where you attach the load, you will train the entire length of the muscle.

Crunch Your Washboard

Techique is everything, and the following pointers may help you concentrate on your midsection. In general, bringing your pelvis toward the belly button will work the lower-ab region, while curling your shoulders and rib cage towards the same center point will build your six-pack, or the upper part of the rectus abdominis muscle. Obliques are the third area, located at the sides of your waist. They are actually a separate muslce, but often considered part of the midsection training routine. Twisting and rotary movements at the waist, like crossing one shoulder toward the opposite hip, typically involves obliquies.

-If you have your hands behind your head, make sure you do not pull on your neck, keeping your chin up, chest out, elbows wide open.

-Try not to lift your whole body off the floor since the abdominal muscles are only responsible for about the first 30° of motion - after that your hip flexors continue to do the job. So the range of contraction is not that great, but it can be very powerful.

-Concentrate on your breathing - exhale on the way up, inhale on the way down.

-Make sure to fully contract and stretch the abdominals during crunches. Let your abdominals stretch at the bottom of the movement but don't let the tension leave.

The abs are a muscle like any other and are stimulated by overload. You can hold a weight a few inches from your face or keep your arms straight above the head while performing crunches to increase the overload and stimulate more abdominal development. Also remember to provide adequate rest for you abs. Remember the rule of soreness: If the muscles are still very sore from the previous workout - don't train them.