There are a surprising number of popular misconceptions regarding abdominal training. We at the Soft Tissue Center spend a great deal of time explaining the realities of low back pain and ab training to patients. If that statement seems contradictory, if you’re under the impression that an intense abdominal workout is supposed to “strengthen” the lower back, you might want to reevaluate what should be included in---or excluded from---a safe and effective ab routine.
So much of what is considered sound abdominal training is, quite simply, bad for your lower back. The wrong exercise could complicate an already existing back problem or actually create a new one.
One major misconception concerns the action of various abdominal exercises — what that action is and where it takes place. The most important---and often the most forgotten---point here is that abdominal exercises include both spinal flexion and hip flexion and that these moves are two entirely different actions with different effects on the lumbar spine (lower back).
Spinal flexion is the curling action of your spine, for example, when you do crunch-type situps. The spinal flexors are the rectus abdominus and the obliques. They are your true abdominal muscles, and they attach from your sternum and ribs to your pubic bone and to the sides of your pelvis.
Hip flexion occurs when you lift your leg, as in leg raises or when punting a football. Your hip flexors are the iliopsoas, which is buried under so many other muscles that it cannot even be seen, and the rectus femoris, which is part of the quadriceps. The psoas portion of the iliopsoas attaches to your upper femur, or thigh bone, and also attaches to the fronts of all your lumbar vertebrae. The rectus femoris attaches to the front of your pelvis and also below your knee.
The above may seem like a lot of tedious anatomical details, but it’s crucial to understanding the rest of this column. Your spinal flexors attach to the ribs and sternum on the front of your body; strengthening them will cause a healthy flattening of the curve of your lower back.
The hip flexors, on the other hand, attach on the “back” of the body, and strengthening them will cause an unfavorable forward pull on your lower back and pelvis. This frequently leads to a swayback, an unhealthy increase in the low back curve.
A swayback upsets the balance of the body’s weight-bearing mechanism. Normally it is the thick bony “body” area of the vertebrae that carries the load of the upper bodyweight. The sway back abnormality places too much stress on the low back, which leads to chronic inflammation. As an early sign of this condition you might experience a dull lower back ache when you get up in the morning, when you’re lying facedown on your bed or the floor with your elbows propped up watching television or reading, or when you’re simply lying facedown. These positions naturally pull on the front of the spine from the hip flexors. When the low back curve is already exaggerated, the position compounds the stress and leads to discomfort or pain.
You don’t need to have powerful hip flexors for bodybuilding or powerlifting. The only activities that require hip flexor strength are gymnastics, ballet, football (for punting) and some martial arts. But those who participate in the above may suffer the consequences. Every gymnast we have treated has suffered from low back pain.
One of the greatest myths of abdominal training is the idea of working the upper and lower abs separately---with situps and leg raises. As we said, the rectus abdominus and obliques, your true abs, are powerful spinal flexors and, in fact, they do come into play when you perform leg raises. But that’s not all that happens.
For you to do leg raises, your true abdominal muscles have to contract isometrically to keep your pelvis stable. But the actual action of the leg raise is a hip flexion, with the powerful hip flexors lengthening and contracting as they normally would, pulling on your lumbar spine. If a bodybuilder or powerlifter has heavily developed legs, they will provide increased resistance, which in turn leads to increased hypertrophy of the hip flexors. The muscle growth leads to increased muscle power, with the end result of further unfavorable changes to the athlete’s low back biomechanics.
Leg raises are usually performed for a higher number of repetitions than other exercises, so your abdominal muscles receive a decreased blood flow due to their semicontracted state while holding your pelvis still. Consequently, less oxygen is transported to the muscle and also less waste products, including lactic acid, are carried away from it. This causes the effect that everyone in the gym calls the “burn.” In this case, a “good burn” can be misconstrued as a good workout.
The fatigued area that you feel in your lower abdomen at the end of a set of leg raises is your hip flexors, which are located in the area that you perceive as your “lower” abdomen. This hip flexor fatigue, combined with the “burn” in your true abdominal muscles, gives you the illusion that you actually trained your lower abs, but it’s just an illusion.
The idea of working the upper and lower portions of a single muscular structure separately suggests a tug-of-war between two people. It’s impossible for only one person, or only one-half of the rope to feel the pressure. But in the case, the leg raise, is caused by the contraction of the hip flexor muscles. It is not caused by the lower abdominal muscles acting like one person on a tug-of-war feeling tension on half of the rope. There is tension on the entire superficial abdominal muscle to hold the pelvis still while the hip flexors contract.
The only way to improve the appearance of your lower abdomen is to lower your bodyfat percentage. At five percent bodyfat you’ll see your abdominals clearly whether they’re trained or not. The normal male physique tends to store bodyfat in the lower abdomen and the sides of the waist. The solution is diet-related---the overwhelming evidence on the subject of spot reducing shows that it’s one of the greatest myths of all times.
Twenty years ago bodybuilders frequently performed 1,000 situps a day during precontest training. That is rarely, if ever, the case anymore. Yet the appearance and muscularity of bodybuilders’ abdominals are greater today than they have ever been. It’s no coincidence that 20 years ago bodybuilders weren’t as concerned with diet and bodyfat percentage as they are today.
After leg raises come two more villains in the abdominal wars---the Roman-chair situp and the decline situp. True Roman-chair situps are performed in the faceup, or supine, position on the hyperextension bench with your legs out straight. Your lumbar spine flexes and hyperextends in this movement, while your hip flexors provide the stability.
Boxers traditionally performed Roman-chair situps, frequently off the hood of a car while someone supported their legs. The hip flexors are so strongly involved in this movement that adolescent males have been known to suffer avulsions, or tearing off, of the rectus femoris at its origin on the pelvis. Consequently, this old-fashioned type of Roman-chair situp is seldom used nowadays.
In the version that’s commonly practiced in the gyms today, you sit on the seat of the Roman-chair bench, hook your feet under the brace and then simply rock back and forth. If you analyze this movement, however, the action occurs in the hip, not in the spine. As with leg raises, it is the hip that is undergoing flexion and extension, not the spine.
This version of the “Roman-chair situp” is a reverse leg raise. A leg raise is performed by raising and lowering your legs, with your upper body braced by either lying down or hanging, or by your forearms. The Roman Chair sit-up braces your legs and moves your upper body in an identical manner; the effects on your lower back are identical as well.
There are exceptions to every rule. In the name of fairness, we cite a bodybuilder who has performed leg raises for more than 40 years with a minimal amount of problems. That exception is Zabo Kazewski, a bodybuilder and Manager of World Gym, who was noted for the high repetitions of both leg raises and Roman-chair situps that he performed daily.
The overwhelming majority of patients who come to the Soft Tissue Center with low back pain, however, have been performing these hip flexion exercises and feeling discomfort either at the time they do them or shortly thereafter. When these patients are encouraged to drop such movements from their workouts, their back symptoms improve.
One of our patients who developed a problem from hip flexor training is a multiple Olympic medalist in the 100- and 200-meter sprints. She experienced an episode of low back pain at one of the premier indoor track meets of 1988. When she returned to Los Angeles and came to see us, her swayback was obvious.
While this woman was lying faceup on the table at rest, I could slide my entire forearm under her lower back with room to spare, indicating the increased curve of her lower back. I inquired about her hip flexor training, and she reported that she had never been stronger in that movement. She was under the impression that the stronger her hip flexors were, the faster she could run. While there is some degree of truth to that theory, it’s not that great a degree.
Once the stress on this woman’s hip flexors was relieved through soft tissue mobilization, I could barely slide my hand under her lower back, indicating the reduced curve of her lumbar spine and the reduction of her back pain—a demonstrable improvement in just 15 minutes. This athlete discontinued her hip flexor training and set personal spring records in the ’88 track season.
A common gym scenario occurs when a bodybuilder or other weight trainer develops a mild case of low back discomfort after reaching the intermediate level of training. Frequently, the individual will acknowledge that he or she has been neglecting the abdominals and then try to make up for lost time by bombing them. The idea is to balance the strength of the back muscles being developed. That’s sound logic but the solution is wrong, especially since such routines typically consist of Roman-chair situps, leg raises, crunches and twists.
The twist, is currently performed in the gyms, is another basic bodybuilding myth—for two reasons. The first has to do with the biomechanical distortion of your lower back when you perform this movement. That portion of each vertebra that guides the movement of your spine allows only five degrees of rotation between the vertebrae, for a grand total of 30 degrees of rotation. Your lumbar spine is designed to move primarily forward (flexion) and backward (extension), as when you do crunches. Performing twists places a shearing force on the fibrous covering of the lumbar discs, especially when you straddle the bench with a staff on your back while doing them. Your pelvis, in this case, bears the weight and becomes fixed, and your lower back takes an even greater torque.
The second myth about doing twists is the idea that you can spot reduce and tone the sides of your waist---you can’t. You tone your obliques, the muscles on the sides of your waist, while you’re doing other abdominal work. As previously discussed, on the normal male physique a greater portion of bodyfat is distributed along the lower abdomen and the sides of the waist. I regret to inform you that leg raises and twists will not change that. Dieting won’t change that genetic predisposition either, but it will alter your appearance by reducing the bodyfat percentage present.
The above discussion presumes that we are dealing with a somewhat normal, healthy spine. If you have low back pain from a variety of problems, the standard form of abusive abdominal training would cause additional complications. You want to be healthy to train today, but if your training is not biomechanically correct, you’ll live with the results 10 and 20 years from now. We want you to still be training then.
Much of what we have said here is contrary to popular opinion; however, we don’t base our information on a particular training style or fad. Our approach is strictly based on factors that cause or contribute to injuries and what we observe on a regular basis in athletes who train at the most famous gyms in the world. We see these patterns again and again.
by Joseph M. Horrigan