Q: What’s so bad about sitting in a chair?
A: Although as you know I’m no fan of slouching (visceral organs, blood flow, breath, and nervous system are all compromised by the head forward slump shown above which is also known to cause headaches), the main damage done by sitting in a chair is the angle of our legs.
When you sit, the bone in your upper leg (the femur) rotates 90 degrees to bring your thigh parallel to the floor, but at best, if you’re really limber, only maybe 70% of that rotation occurs at the hip joint. If you have a tight back or tight hips, even less of the rotation happens in the hip joint.
Low Back Pain
That means you get the remaining 20% (or more) of that movement by compressing the lumbar spine in your low back. Can you spell yikes? The low back muscles are deformed (*see below) and the lumbar vertebrae squish the discs between them as the pelvis tilts backward.
This is why ergonomics experts say you should keep your knees below your hips by adjusting your chair height when you are sitting in an office chair. It’s also why when you sit on the floor you feel less strain by sitting on a cushion – it raises your hips and decreases the angle of your legs, relieving a little of the low back compression.
Chairs are far from the only culprit in back pain. The National Institute for Health estimates that four out of five adults will experience low-back pain at some time in their lives.
“Low back pain represents so many different diseases that there really hasn’t been a breakthrough treatment,” said Dr. Russell K. Portenoy, chairman of the department of pain medicine and palliative care at Beth Israel Medical Center in New York. “It’s good for the public to know how little we know.”
Physicians say lack of movement causes back pain.
We don’t use our muscles because our muscles are weak and our muscles are weak because we don’t use them.
*There is no neutral position for all of our back muscles at the same time. This means at least some of them are always fully loaded (bearing weight) when we’re sitting.
The longer we sit without moving, the more stress those muscles are subjected to, and the stress increases with longer immobility. (Yep, another exponential rate of increase!) Recovery time for a stressed muscle is longer than the period of stress, and yes, the recovery time also increases at a higher rate than the length of the load bearing time, i.e, the longer the period of stress (the stress, in this case, of being motionless) the more out of proportion the recovery time becomes.
Experts say that fear of sensation, more pain, or injury contributes to the avoidance of movement which is a common response to already existing low back pain.
Yet physicians are quick to point out inactivity tends to complicate and prolong pain.
“We routinely recommend that patients become more active.” Low-Back Pain: Research and Delivery of Evidence-Based Care Complementary and Alternative Medicine January 2009]
“We assure them that in most cases activity and exercise are beneficial, safe components of their management.” http://nccam.nih.gov/news/newsletter/2009_may/interview.htm
Gert Bronfort, D.C., Ph.D., is vice president of research and director of the musculoskeletal research program at Northwestern Health Sciences University (NWHSU).
We may publish any content, comments or ideas sent to us.
Name may be withheld by request.
© 2011, The Magazine of Yoga, LLC.