Columbia Advanced Chiropractic Blog, Body at Work

Why We Don’t Do Sit-ups, Leg Lifts, and Low Back Extensions When In The Gym

All too often, when I’m in the gym, I see people doing sit-ups, leg lifts, and back extensions. The reason people do these exercises is to train their abdominal muscles and their low back muscles. People figure that if they sit all day long, they have to go to the gym to strengthen their low backs and train their stomach muscles. Although half of this is true (the stomach muscles should be worked on), the truth is that these exercises actually create low back problems and are doing nothing to help you! Allow me to explain.

First things first. The stomach muscles do not attach to the thighs. They primarily attach from the bottom of your rib cage to the bottom of your pelvis and pubic bone. This means that when you bend your body forward past 30 degrees (sit-up) or raise your knees to your chest (leg lift), there is no abdominal muscle contraction that is actively occurring. You are, however, working your hip flexor muscles. If you recall from one of our previous discussions (see archive for lower cross fix pattern), the hip flexor musculature tends to be facilitated, or too tight. In addition, the psoas muscle, which is the most powerful of the hip flexors, originates on the anterior discs in your lower thoracic and part of your lumbar spine. This means that too much shortening of this muscle can directly influence spinal biomechanics in a very bad way. The more we train these muscles, the greater the likelihood of low back injury. This is certainly something that we want to avoid! People think that they’re training the stomach muscles because they feel the ‘burn’ in the stomach region. This is because the psoas muscle, which is about the diameter of your forearm, pushes out against the abdominal wall, thus making you feel like you’re training your abdominal region. /p>

In regards to back extensions, this is another activity that violates the rules. Most people’s low back muscles tend to be too tight. Sitting all day long at a desk allows for these muscles to shorten and lose their ability to stretch. The last thing you want to do is go to the gym and make these muscles even shorter and tighter. The large low back muscles are another part of the lower cross fix pattern. If we go to the gym and actively train the hip flexors and low back muscles, we are making imbalances even worse and by doing so, we are creating injury. In addition, by training these muscles, we are telling the abdominal muscles and gluteal (butt) muscles to shut off. This is a recipe for injury as we are actually training the wrong muscles, thinking we’re training the proper ones.

So, with this information in mind, what should we be doing when we go to the gym? For starters, it is sometimes a good idea to find a highly qualified fitness professional to teach you the proper way to do things. The best way to find a good trainer is to ask your doctor, chiropractor, physical therapist, etc… There are a lot of fitness professionals out there and not all are well-versed in anatomy and kinesiology. If you are going to spend hard-earned money, make sure you’re paying for knowledge… it will likely save you from injury.

If you opt to do things on your own, then you have to develop an understanding of anatomy and kinesiology. Just as you wouldn’t delve into working on your car unless you had a good knowledge of how engines work, nor should you just go into a gym and start doing things without knowing how your body works.

Here are some basic points to consider when you want to train your abdominal muscles. If you place one hand palm-up on your sternum and the other palm-up on your pubic bone, you will notice that the hands only get closer when you either bring your thoracic cage to your pelvis (first 30 degrees of body flexion) or your pelvis to your thoracic cage (posterior pelvic tilt). This means that to train your stomach muscles, you need to perform exercises that achieve these movement patterns. Please note that this does not apply to core stabilization exercises, but we will cover that topic on another day. As far as low back muscles go, very few people have a need to strengthen them as they’re already too tight. Although the research shows that the small low back muscles are inhibited (weak), these muscles actually get trained when we work on core stabilization and/or train the abdominal muscles. Performing back extensions will train the larger, longer muscles more-so than the little, stabilizing muscles.

I am hoping that a little information on this topic will go a long way. We go to the gym to make our body healthier, not hurt it, and we need to make sure our exercises are training the muscles we think they’re training.

1 Comment »

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    Comment by Lousy — July 29, 2010 @ 3:51 PM

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