Abdominal Muscle Training Demystified
REALITIES AND MARKETING MYTHS
Steve Daisey MPT, CSCS

What is the best abdominal exercise?
This is a question physical therapists and personal trainers are asked frequently. The best abdominal exercise is the one that works the abdominals the hardest. However, the more stressful the exercise is, the more difficult it is to keep the proper form and maintain safety.

Research shows there is no difference between the typical gym/mat exercises in terms of how much they stress the abs (1-3). With crunches, it makes no difference whether your feet are on the floor or in the air, if your legs are straight or bent, if you are lying on an incline, or if you are doing a sit-up or a crunch.

Exercises in which the legs are pulled toward the chest at the same time you are performing a crunch, or ones that involve lowering the legs, have been shown to increase the overall activity of the abs beyond what only a crunch exercise can do (2-5). This makes it a more effective abdominal exercise.

However, it is important to remember that there are a number of ways to perform these types of exercises incorrectly (i.e. coming out of a pelvic-neutral position) that can make them unsafe.

The most important thing is to remain safe and be sure your form is correct if you are performing a more advanced, more effective abdominal exercise in which the legs are involved.

Do any of the abdominal exercise machines sold on television work better than performing a crunch?
According to the few independent research studies done, the results are mixed.

Compared to the standard abdominal crunch exercise, the Ab-Flex and Ab-Roller showed no additional increase in use of the abdominal muscles during exercise, and no more improvement in strength over an 18-week training period (6). While the Ab-Roller did not increase abdominal stress, the head-rest did decrease neck muscle stress during the crunch exercise (7). Therefore, this can be recommended for people who experience neck pain during the crunch exercise.

A second study (7) showed that the Ab-Shaper did result in more activity of the abdominal muscles than the standard crunch exercise. However, that exercise incorporated the legs by pulling the knees toward the chest at the same time, and therefore should be more stressful on the abs as mentioned before (2-5).

In my opinion, mechanical devices can add some variety to abdominal exercises, but none of them create a more effective abdominal workout than the numerous exercises you can do without them.

What about electrical stimulators that are supposed to work the abdominal muscles without exercise?

Probably the all-time biggest scam with respect to strength training is the use of electrical stimulators. Electrical stimulators have been advertised as being capable of increasing strength, decreasing body weight and body fat, and improving muscle firmness and tone. Electrical stimulation is performed by sending electrical impulses though pads placed over the muscle which results in a muscle contraction.

While studies show that electrical stimulation of a muscle over time will improve its ability to contract, there are no good studies that have ever found electrical stim to improve functional strength (where your limbs are actually moving) or human performance (9-16). Claims that it can reduce body fat or weight are even more absurd.

As a way to gain strength and muscle size, electrical stimulation fails miserably when compared to exercise. Don't be fooled by marketing schemes which claim othesdise.

Is it possible to isolate the upper or lower abs?
No. Abdominal muscles do not work that way. The terms "upper" and "lower" refer to region. The rectus abdominus muscle contracts all areas of the muscle or not at all (8).

Studies DO show that exercises which incorporate the legs as mentioned before may increase the activity and contribution of the lower region of the abdominal muscles, as well as the oblique muscles on the side (the love handles) (2-4,6).

Can strengthening my abdominals help protect against lower back injury?
Yes. Studies show time and time again that people with current or previous episodes of back pain have diminished abdominal strength (17-20). However, abs are only part of the story. Other studies suggest hip weakness and back muscle weakness are just as, if not more important to protecting against lower back strain (19-20).

To prepare the abdominals to protect against back injury, it is important to strengthen them in the positions in which they protect the spine. In other words, while crunches or curl-ups are nice at building up the abdominals, that exercise is largely ineffective for lower back pain because the abdominal muscles perform a different type of movement when protecting the spine. These protective movements are better trained in standing.

For more information on abdominal training, contact Eden Smith at Seneca.


References

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1. Willett GM, et al: Relative activity of abdominal muscles during commonly prescribed strengthening exercises. J Strength Cond Res 2001 Nov;15(4):480-5.
2. Guimaraes AC, et al: The contribution of the rectus abdominis and rectus femoris in twelve selected abdominal exercises. An electromyographic study. J Sports Med Phys Fitness 1991 Jun;31(2):222-30.
3. Sarti MA, et al: Muscle activity in upper and lower rectus abdominus during abdominal exercises. Arch Phys Med Rehabil 1996 Dec;77(12):1293-7.
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