As a doctor, you run across all kinds of research. Here’s an article that I wanted to address. (http://news.bbc.co.uk/2/hi/health/6187080.stm) Allow me to preface the entire article with a few statements regarding research. As a chiropractor and wellness professional, I take a slightly different stance on a lot of research. The whole solution in research relies on the question the researchers ask. If you ask the wrong question, you can never get the right answer and science can never tell you what question to ask!
In the scientific world, the “Gold Standard” is the double-blind randomized controlled trial, meaning that those participating are broken up into two groups and neither group nor the doctors supervising are aware which group is getting the real treatment and which group is getting a placebo. Now this study is far from the “Gold Standard” as it is only 22 people (they are usually much larger) and all of the patients knew they were getting an MRI. With that being said, let’s look at what the study revealed and break it down.
According to the article, researchers “proved” that leaning back is the best position for your back. Now if this is correct, all of our mothers and grandmothers had no idea what they were talking about when they told you to sit up straight. Here is their method: “Twenty two volunteers with healthy backs were scanned using a positional MRI machine, which allows patients the freedom to move – so they can sit or stand – during the test.” So let me ask you, how did they measure “healthy backs?” Did they define it as to whether the test subjects had proper curvature of the spine? Did they define it as subjects that could move fully through proper ranges of motion? Well, in scientific research it usually just means those without symptoms. So if you don’t have a symptom today, then obviously you have a healthy back! They also just looked at one individual portion of the back, the lower back or lumbar spine, and looked to determine what spinal angles caused the least amount of strain on the lumbar vertebral discs. The problem lies with the fact that the lumbar spine NEVER operates in and of itself! Your spine consists of 24 movable segments, NOT just the 5 lumbar vertebrae and discs. Notice, the researchers never asked what is the healthiest position for your entire spine, only what puts the least amount of force on the lumbar intervertebral discs! Look at the picture of the fake people sitting in the chair. Does the one with 135 degrees look the healthiest for the entire spine? I would say no!
So then, you may be wondering, what is the correct question? I’m glad you ask! A better question would be “How were we designed and what is the proper position based on actual biomechanics of the entire spine?” For that, we will need to look at how we developed. In the womb, we develop our first curve called a kyphosis. That is the flexed/rounded posture that allows us to fit in our mommy’s womb. After we are born, the next curve to develop is called a lordosis and is a reversal of the neck curvature. This curve develops when babies begin to lift their heads to look around. This is inherently smart as it places our head directly over our shoulders so that we can have stability. When we learn to crawl, our 3rd and final curve develops in the low back. All of these curves together work perfectly to add strength to our spine. These curves also create a proper weight bearing line that goes from the ear to the acromion process of the shoulder, to the hips, to the knee, and to the ankle. I urge you to look at a toddler and notice how perfect their posture is and how all of these landmarks line up.
As we age, we begin to be required to sit as almost everything we do is seated. Kids are now forced to sit for close to 8 hours a day in a small desk to learn whatever it is the schools feel is necessary. Add in the fact that most kids will then get home and watch copious amounts of TV or play just as many video games and you have children now sitting for 12-16 hours in many cases! Does anyone truly believe that we were designed to sit for any extraneous amount of time? Absolutely not! However, the demands of our society often put us in those types of situations.
Let’s look at what happens when you sit improperly from a neurological and physiological standpoint. When we slouch, or sit at 135 degrees, our backs, most often in the neck and low back, are almost certainly rounded and cause off loading of the facet joints which provide constant movement/position information to the brain. The offloading of the facets decreases function to the spinocerebellar (movement/position sense) pathway of the spinal cord that feeds directly into the cerebellum. The function of the cerebellum is most often to determine where we are in space, initiate movements, and also drives the cortical (conscious thought) part of the brain. Now the cerebellum is getting decreased input so the act of initiating movements will be worse which is often demonstrated by poor balance and coordination. On top of that, the cerebellum is no longer feeding the frontal cortex of the brain so rational, complex thought and learning are all diminished. Sounds a little like ADD and cognitive decline to me… Add in the fact that stimulation of the cerebellum also feeds the erector spinae muscles, the muscles that give your back strength and stability, and you have decreased strength of the spine. I could go on forever.
I want you to look at the picture again. At 135 degrees, our neck is placed in a traumatically flexed position so that our eyes can see equally with the horizon. Imagine your head is like a bowling ball. If I asked you to hold that bowling ball directly over your shoulder in your hand, it wouldn’t be that hard. Now if I slowly took that out away from your shoulder, your arm would begin to fatigue as the perceived weight is greater the farther you are from the fulcrum. Now think about that with your head. The farther it goes forward, the weaker the joints in the neck become so now your head starts to drop and to compensate you begin to develop arthritis in the joints as the body tries to stabilize it.
This is only the beginning. Eventually, this will cause you to slouch, causing the flexor muscles in your body to become very tight and the extensor muscles will be stretched and become even weaker! Keep this cycle going and you start to develop a hump like so many of the elderly people in this world.
How then should we sit? Optimally, we would sit for as little as possible as movement fires the brain and the brain controls every cell, tissue, organ, and system in the body so when the brain is working at a higher function, so does the body. However, if you must sit, it would be wise to sit up on your ischial tuberosities or the bones that you can feel in your buttocks. This is most easily done on the edge of the chair and causes activation of your core musculature, facet joints, and cerebellum. It will also help to keep your body in the proper biomechanical weight bearing position. As well, frequent breaks to get up and move would be wise as movement feeds the brain! When we sit, certain muscle groups tend to get tight so stretching them would be advantageous as well. Doing a hamstring stretch a few times an hour would be very wise as they tend to be shortened in a seated position. Also, overhead reaches are another good exercise as they go directly against the postures we are fighting. To do them, pull your hands up by your head, making sure the thumbs are turned to the back, and stretch as high as they can go. These will help to strengthen the back/shoulder musculature to help decrease poor posture. All of these things will help you to live a longer, healthier life!
I hope that you have enjoyed my rant and at the same time learned something useful. Until next time!
Yours in Health,
Dr. James Ashley, DC