The Myths of Lower Abs and Spot Reduction
Aaron Loynes MPT, CSCS
Brent Seegraves MPT, CSCS
As physical therapists we are often asked questions regarding exercise and fitness by our patients. By far the most common question: “What exercise can I do to get rid of this belly and make my stomach flat?” Now to the educated reader, this questions may seem a little silly as we all know there is no one exercise that can make your stomach flat; but on closer analysis it is 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 will no doubt see at least one ad for a weight loss product or a miracle abdominal exerciser. It only takes minutes from your day to achieve a lean beach worthy body! Now, if this were the truth then every fat lazy couch potato would sport a six pack by Memorial Day. He would strut around on the beach with a three cheese meat lovers pizza in one hand and an icy forty ounce malt beverage in the other with no regrets as long as he goes home and uses the Miracle Abdominator 4,000,001. Now we all know that this isn’t true but the commercials can be convincing. This article will attempt to clear up some of the common misconceptions of abdominal training.
First, let us review the anatomy of the rectus abdominus – your “six pack muscle.” The rectus abdominus 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 abdominus contracts it pulls the attachments closer to each other as clearly demonstrated when one performs a crunch or sit-up.
The “lower abs” myth
Anatomy is pretty cut and dry yet people tend to argue that the 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 signal for contraction spreads through all of the fibers of the muscle causing a contraction. Anatomically there is 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 are that talented or have that 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 thumb and index finger with tension on the band. The band is your rectus abdominus, the left end of the band is your rib attachment and the right end is your pelvis attachment. Imagine that you are performing a crunch. Let your left hand come toward your right hand as if the rectus abdominus was concentrically contracting. Did the right or left half of the rubber band do more work? They are equal! Regardless of the exercise performed, assuming it is biomechanically correct in form, the results are always the same. The rectus abdominus activates as a unit.
Now why would people believe that you can isolate one half of the muscle over the other half? It is a myth that has been around since people first started training their abs crunches for the upper abs and leg lifts for the lower abs. Again, lets look at it logically the abdominal muscles do not 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 are 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% 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 are feeling with this movement is a more complete, stronger contraction of the abdominals than you experience with traditional crunches. You have not isolated one portion of the muscle from the other. Other lower ab exercises include 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 dont attach to the legs) the burn you are feeling is most likely your iliopsoas muscles and your abs from a long isometric.
So what is a good effective way to fully work your rectus abdominus? The safest, easiest way to do it is with a crunch while the hip flexors are reciprocally inhibited don’t worry, we will 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 perform the abdominals will scream for mercy.
Please keep in mind that no matter how much you work the abdominal muscles, you will not magically develop that six pack you desire unless you clear away the layers of fat that are obscuring the muscles. According to many of the infomercials for magical abdominal exercise devices you can burn away all of your midsection fat by performing exercises with their device for just 3 minutes a day. Again, the educated reader is already aware that spot reduction is a myth but it bears repeating: It is physiologically impossible to choose where your body will burn fat from. Read that again. When you perform an activity that is aerobic in nature, and you begin to need more fuel your body will pull that fuel from its fat stores. Your body will pull from everywhere to supply the fuel, and there is no way you can tell your body where to take it from.
So what about the claims of magical fat loss from an abdominal exercise? Lets first 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 of time about 200 calories in 10 minutes for a 200lb 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 6 minutes a day is going to give you a lean sculpted midsection in just 3 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 aerobic exercise.
The aforementioned is based upon sound anatomical and biomechanical principles. While striving to build our best physiques, we must not stray from the general scientific foundations of exercise instruction. All individuals involved in exercise prescription have a responsibility to question the safety and effectiveness of any given exercise. Failure to do so perpetuates these fallacies among the fitness community. Our patients and clients deserve educated fitness instruction in order to prevent injuries while achieving their goals.