It’s the sexiest thing to look at and the hardest thing to get. Some claim it only takes 5 minutes, while others do it for a half-hour. Many use machines and devices, but most prefer it “au natural.” Pull your mind out of the gutter and open it up to new information about the most misunderstood group of muscles – the abdominals. We are here to answer everything you wanted to know about abs, but were too afraid to ask. Just remember, there are no stupid questions, just stupid people. So read what science has to say about ab training and become the “abdominal guru” in your gym.

Anatomy Review
First let’s review a little anatomy of the trunk musculature. The muscle that is known as the “six-pack” is the rectus abdominis (RA). It flexes the trunk so the rib cage moves toward the pelvis. It covers the “corset” of your trunk, the transverse abdominis, which is responsible for keeping your internal organs internal. The external oblique muscle fibers diagonally stretch over each side of the trunk with their contribution being to assist the rectus abdominis in trunk flexion when working together, or flexing the trunk laterally and rotating it to the other side when working unilaterally. The external oblique muscle fibers run in the opposite direction of the internal oblique muscle fibers. In addition to assisting the rectus abdominis with trunk flexion, they are lateral flexors and rotate the trunk to the same side.

Q. The “ab roller, torso track,” and “ab wheel” inundate the infomercials, not to mention the gym. Are they really that good?
A. Well, yes and no. A research study out of Australia confirmed that the “Abshaper,” an arched metal device that allows rocking forward, does have a role in exercising the abdominal musculature [1]. It activated the upper portion of the rectus abdominis (RA) more than a conventional trunk curl, but activation was the same for the lower portion of the RA. An explanation for this may be that when using the “Abshaper,” spinal flexion is initiated with the upper portion of the RA and progresses to the lower portion, as opposed to being initiated with the lower portion and progressing to the upper portion as in a conventional sit-up. With the supported headrest, it also reduced neck strain. Another study compared the “Ab-Flex,” “Ab-Roller,” and standard crunches and found no significant difference in abdominal strength or reduction of body fat [2]. The “Ab-Wheel” is inexpensive and portable, but we haven’t come across any studies to back up its efficacy. You can achieve the same results using a barbell with revolving sleeves and rolling it along the ground. We also haven’t seen any studies on the “Torso-Track”, but with the price of these devices ranging anywhere from $50 to over $150, it makes more sense to save your money, so roll a barbell around instead.

Q. All of a sudden I see people doing ab work on large balls. Can this give me great abs or is it just another gimmick?
A. Stability balls or Swiss balls have been used in physical therapy for years and are just starting to come into the gym scene. With little expense, these toys just may have some merit with abdominal training. A recent study showed that performing curl-up exercises on a ball increased abdominal muscle activity and placed a higher demand on the motor control system than curl-ups on a stable surface [3]. It also appeared to increase external oblique muscle activity larger than those of other abdominal muscles. Curl-ups on balls change both the level of muscle activity and the way that the muscles coactivate to stabilize the spine and the whole body. Definitely not a rip-off, these Stability and Swiss balls may help you through a low back rehabilitation program and advance you into a challenging exercise routine.

Q. I crunch and crunch and crunch – and still no abs. What’s the deal?
A. Are you still eating and eating and eating? Well-defined abs are not so much a product of exercise as they are of diet. You must peel away all of the layers of body fat for the abdominal muscles to peak through. You can increase their size (hypertrophy) with exercise, but you must decrease your body fat for all of that exercise to pay-off. Training for muscular hypertrophy means the typical bodybuilding routine of 3-4 sets per exercise and 8-12 reps. The abdominal muscles are the same as any other muscle and should only be trained at the maximum once every 48 hours, not everyday. You wouldn’t dream of doing legs everyday, would you? Well, your abs need some rest to grow too! Incidentally, doing millions of crunches is an example of muscular endurance, not strength or hypertrophy. So while a continuum of crunching may decrease or prevent low back pain [4], it won’t do much for making your belly-button ring look good.

Q. I’ve heard a lot lately about “core training” and “functional training.” What is it and how does it involve my abs?
A. This is largely sports-specific training and it not only gives you strong abdominal muscles, but it can improve your game too. Stabilization and power come from the trunk of the body. The power that generates a baseball batter’s home run swing comes from the core of the body and transfers out to the arms. Many overuse injuries can trace their origins back to poor trunk control and strength. Although most sports and activities in daily life require bending and twisting of the trunk in a standing position, most people don’t train their abs that way. Ab training is typically done lying supine on the floor with the knees bent. Are there any sports or daily activities that require you to be in that position and use your abs? Get your head out of the gutter again! Functional training says to choose exercises that mimic sport or activity and train for movements, not muscles. So if you want to improve your golf swing, you could reproduce that movement with resistive tubing or weighted cables for a moderate number of sets and reps to increase strength, or for a low number to increase power. Because this type of training also tends to be metabolic, you may shed some unwanted body fat leading to functional-looking abs!

Q. In my Pilates class they say that straight leg sit-ups strengthen the abs without hurting the low back. I’ve always thought that you should bend your knees to protect your low back and that it’s even better to anchor your feet. What’s right?
A. When the feet or legs are restrained during abdominal exercises, the iliopsoas muscle group (hip flexor) is the primarily working, not the abdominals. Essentially, you are bending at the hips to raise your trunk. In addition, anchoring the feet leads to an arched back and possible shearing stress on the lumbar spine. Studies have found that performing sit-ups with bent knees didn’t significantly reduce lumbar spine compression [5, 6]. Certified Pilates instructor and former Ms. Olympia Carla Dunlap-Kaan says Pilates classes emphasize unrestrained feet with a slow and controlled trunk curl to a sit-up position and then equally slow and controlled to the lying flat position. “The difference with Pilates is that you are curling your trunk forward vertebrae by vertebrae. Sure the hip flexors will come into play, but they will work synergistically with the abdominals and that’s more functional,” Carla explains. Your feet are never glued to the ground when your trunk moves during everyday life or sports. To prevent injury and increase performance, your trunk needs to know how to coordinate movement in real-life situations, not just in the gym.

Q. I usually see people training their abs while they are lying flat on the floor. Is this the best way?
A. Absolutely not for those who are healthy and free from back problems. People who train their abs solely in a supine position either have had a back injury, or are just tired! And they are missing out on some important ranges of motion for strengthening and function. Maximal muscle tension is developed with a pre-stretch on the muscle, so try initiating the ab curl from beyond neutral, or about 15o of hyperextension. Of course, you’ll have to get off the floor for this. Try using resistive tubing, weighted cables, stability balls, or a curved Roman Chair. Also experiment with different functional patterns like diagonals. This will not only increase the utilization of all of your abdominal musculature, but it will also transfer to daily activities and sports.

Q. Is there a correct way to breathe when I am doing abdominal exercises?
A. For healthy people, Mel C. Siff, PhD, in his book Facts and Fallacies of Fitness, suggests inhaling before each concentric contraction and holding the breath. Just before each slow eccentric contraction, exhale forcibly by squeezing in more of the transverse abdominus and pelvic floor. Breath holding produces maximal abdominal tension and protects the lumbar spine. Pilate’s classes teach similar breathing techniques. However, older adults and those with a cardiovascular problem should breathe normally and not hold their breath.

Q. What is the verdict about separating ab training to hit the upper and lower abs and the obliques?
A. There is really no validity to the argument that you can train just your upper abs by doing a certain movement and just your lower abs by doing a different movement. The rectus abdominis muscle is connected and when it performs its’ job of forward trunk flexion, all of the fibers work as a whole. Indeed, even the obliques assist with trunk flexion. However, there are certain exercises that will emphasize more of the upper abdomen, like the partial curl-up or “Ab-roller” curl-up. It is false to think that the typical exercises people do to target their lower abs like hanging leg raises and reverse curl-ups totally isolate that area. Reverse curl ups may emphasize the lower part of the rectus abdominis as opposed to the upper, but the hip flexors largely come into play. During hanging leg raises, the abdominals work only as stabilizers while they isometrically contract to allow the hip flexors to curl the lower body. It certainly feels challenging because it is difficult to stabilize the spine while the body is hanging without support. Rotating movements will emphasize the obliques, but the rectus abdominis works during these movements, also.

Q. What are the best ab exercises I can do without hurting my low back?
A. Researchers in Canada determined the exercises that would most “challenge” the abdominal musculature without “penalty” to the lumbar spine with respect to compression forces [5]. They reported that there is no single best exercise to recruit all of the abdominal muscles simultaneously, and that conditioning level, medical history, and progression are important to keep in mind. With that said, the straight-leg sit-up and bent-leg sit-up had the highest muscle challenge, but also involved higher lumbar compression. These exercises should be performed by those with previous training experience. Partial curl-ups produced less spinal compression, but were also a lower muscle challenge. This is a good exercise for beginners or for those with a previous back injury. One exercise that rated very high in challenging the obliques without lumbar compressive loading is hardly ever seen being done. The isometric side support is performed by raising the torso and legs off a sit-up bench while supporting one side of the body by only the foot, elbow, and forearm. This exercise also strengthens the quadratus lumborum muscle of the low back, a spinal stabilizer [7]. Some exercises to avoid included supine straight or bent-leg raises, cross-knee curl-ups, and hanging bent-leg raises.

References
1. Warden, S.J., H. Wajswelner, and K.L. Bennell, Comparison of Abshaper and conventionally performed abdominal exercises using surface electromyography. Med Sci Sports Exerc, 1999. 31(11): p. 1656-64.
2. Demont, R.G., et al., Comparison of two abdominal training devices with an abdominal crunch using strength and EMG measurements. J Sports Med Phys Fitness, 1999. 39(3): p. 253-8.
3. Vera-Garcia, F.J., S.G. Grenier, and S.M. McGill, Abdominal muscle response during curl-ups on both stable and labile surfaces. Physical Therapy, 2000. 80(6): p. 564-569.
4. Rissanen, A., et al., Isokinetic and non-dynamometric tests in low back pain patients related to pain and disability index. Spine, 1994. 19: p. 1963-1967.
5. Axler, C.T. and S.M. McGill, Low back loads over a variety of abdominal exercises: searching for the safest abdominal challenge. Med Sci Sports Exerc, 1997. 29(6): p. 804-11.
6. Juker, D., et al., Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during a wide variety of tasks. Med Sci Sports Exerc, 1998. 30(2): p. 301-10.
7. McGill, S., D. Juker, and P. Kropf, Quantitative intramuscular myoelectric activity of quadratus lumborum during a wide variety of tasks. Clin Biomech, 1996. 11: p. 170-172.