The only way to truly lean up your midsection is to lean up your entire body with a combination of weight training, proper diet and cardio.

By Aaron Loynes MPT, CSCS and Brent Seegraves MPT, CSCS

As physical therapists, our patients often ask us questions regarding exercise and fitness. By far the most common question is, “What exercise can I do to get rid of this belly and make my stomach flat?” Now to the educated reader, this question may seem a little silly – we all know there’s no “one exercise” that can make your stomach flat; but on closer analysis it’s easy to understand the confusion the general public has regarding exercise and fitness. One has only to watch TV for an hour on a Saturday and you’ll no doubt see at least one ad for a weight loss product or “miracle” abdominal exerciser. “It only takes minutes from your day to achieve a lean, beach-worthy body!”

Now we all know this isn’t true – but the commercials can be convincing. This post will attempt to clear up some of the common misconceptions about fat loss and abdominal training.

Ab anatomy.

First, let’s review the anatomy of the rectus abdominis – your “six-pack” muscle. The rectus abdominis originates from the fifth through seventh ribs and inserts to the symphysis pubis. The sheet of muscle is actually six total muscles enclosed within fibrous tissues, three on each side with the linea alba separating them in the center. As the rectus abdominis contracts, it pulls the attachments closer to each other as clearly demonstrated when one performs a crunch or sit-up.

“Lower abs” myth.

Anatomy is pretty cut and dry – yet some argue that abdominals are divided into an “upper” and “lower” section and that each section can be isolated with certain exercises. This idea is ridiculous – it would be the same as claiming you could isolate the upper portion of your bicep muscle from the lower portion with a special type of curl. When a muscle contracts, the chemical and electrical signals for contraction spread through all the fibers of the muscle, causing a contraction. Anatomically there’s no other insertion point in the middle of the muscle belly. It attaches at the ribs and the pelvis.

How would you activate one portion and not the other? If you’re very talented or have tight muscle control, you wouldn’t need to exercise your abs. Use this analogy: Take a rubber band, cut it so that it looks like spaghetti or string. Now hold it at each end between your right- and left-hand thumbs and index fingers with tension on the band. The band is your rectus abdominis, the left-hand end of the band is your rib attachment, and the right-hand end is your pelvis attachment. Imagine you’re performing a crunch. Let your left hand come toward your right hand as if the rectus abdominis was concentrically contracting. Did the right or left half of the rubber band do more work? They’re equal! Regardless of the exercise performed, assuming it’s biomechanically correct in form, the results are always the same. The rectus abdominis activates as a unit.

Now why would people believe you can isolate one half of the muscle over the other half? It’s a myth that’s been around since people first started training their abs – crunches for the “upper abs” and leg lifts for the “lower abs.” Again, let’s look at it logically – the abdominal muscles don’t attach to the legs, so why would a leg lift isolate the lower abs? The easy answer here is, “It doesn’t.”

When you perform hanging leg raises, you’re calling your hip flexor musculature into play as the initial prime movers while your abdominals do the work of stabilizing your pelvis. At the top of the movement, unless you do it wrong like 80 percent of the people I see at the gym, your pelvis will curl up and your abs will take over the movement, giving you a complete contraction of the muscle. So, in essence what you’re feeling is a more complete, stronger contraction of the abdominals than you experience with traditional crunches. You haven’t isolated one portion of the muscle from the other. Other examples which purport to strengthen the mythical lower abs are exercises where you lie on your back, lift your legs in the air and kick them up and down – again your abs are working isometrically as a stabilizer while your hip flexors move your legs up and down (remember, abs don’t attach to the legs) – the burn you’re feeling is most likely your iliopsoas muscles and your abs from a long isometric.

Training your abs.

So, what’s a good effective way to fully work your rectus abdominis? The safest, easiest way to do it is with a crunch while the hip flexors are reciprocally inhibited – don’t worry, we’ll explain: Lie on the floor on your back with your feet up on a chair (or stool, or ball) and squeeze your heels into the object under your feet to get a light hamstring contraction; squeeze your glutes (which will roll your hips back slightly); and now perform your crunches. You only need to crunch up far enough to lift your shoulder blades off the floor to get a complete contraction. Why is this effective? Using your hamstrings and glutes during the exercise causes your hip flexor musculature to shut down, making it easier to isolate the abs. If the low back remains in contact with the floor and a four-second controlled count (two seconds up and two seconds down) is performed, the abdominals will scream for mercy.

Spot reduction.

Please keep in mind that no matter how much you work the abdominal muscles, you won’t magically develop the six-pack you desire unless you clear away the layers of fat obscuring the muscles. According to many of the infomercials for magical abdominal exercise devices, you can burn all your midsection fat by performing exercises with their device for just three minutes a day. Again, the educated consumer is already aware that spot reduction is a myth, but it bears repeating: It’s physiologically impossible to choose where your body will burn fat. Read that again. When you perform an activity that’s aerobic in nature and you begin to need more fuel, your body will pull the fuel from its fat stores. Your body will pull from everywhere to supply the fuel and there’s no way you can tell your body to take it from a specific area.

So, what about the claims of “magical” fat loss from an abdominal exercise? Let’s look at the most efficient fat burning aerobic exercise – cross-country skiing. What makes this exercise so good? It uses almost every muscle group in the body and requires enormous amounts of calories to maintain the activity at a high level for a prolonged period – about 200 calories in 10 minutes for a 200-pound man, in fact. Weightlifting burns approximately 45 calories in 10 minutes. Many of these magical abdominal fat burner machines are nothing more than a sit-up performed against resistance – basically a weight training exercise – so it would take almost 50 minutes of performing the exercise to burn the same number of calories you would burn cross-country skiing for 10 minutes! It seems fairly illogical then that using your “Miracle Abdominator 4,000,001” for six minutes a day is going to give you a lean, tight midsection in just three short weeks as promised. The only way to truly lean up your midsection is to lean up your entire body with a combination of weight training, proper diet and cardio.

References:

Anderson J, Grant’s Atlas of Anatomy 7th Edition, Williams and Wilkins 1980.

Kendall F, McCreary E, Provance P, Muscles Testing and Function 4th edition. Wilkins and Wilkins 1993.

Netter FH, Atlas of Human Anatomy 2nd edition. Novartis 1997.

Norkin C, Levangie P, Joint Structure and Function 2nd Edition. FA Davis 1992.

Rosato F, Fitness for Wellness 3rd edition. West Publishing Company 1994.