In the February, 2008 issue of Dental Economics, an article discusses the ergonomics of sitting, particularly when it comes to practicing dentistry. It is known that sitting places greater amounts of pressure in the discs of the spine. Reclining reduces this pressure, and by far, the most pressure is induced when sitting straight up, using all of the trunk muscles hold the trunk up. This posture of “sitting up straight” is just too fatigable, and cannot be held for long. So, most dentists choose to slump in their chair.
Slouching causes a gradual lengthening of the supporting ligaments in the back pf the spine. This eventually leads to low back instability, and a career full of low back pain for most dentists. Slouching is bad for the back. It can lead to disc herniations, particularly when the dentist is slouching and twisting.
A better approach would be to use a saddle chair that tilts the pelvis forward 10-15 degrees. This allows the lumbar spine to be in a more neutral posture, with less muscle effort. This sitting position is closer to the posture assumed in standing. One of the keys, is to have the thighs sloping downward, so the thigh muscles are not stressed.
Saddle chairs are curiously expensive, though. If you can’t spend $600 on a new chair, and you need to assume a posture similar to a dentists, you can substitute a regular chair that raises to allow the thighs to drop off. Then you can use some kind of wedge that will allow your pelvis to tilt forward.
Don’t let your pelvis tilt too far, though. Tilting the pelvis too far may also be damaging to the spine from hyperlordosis. This can cause facet syndrome in the lumbar spine.
Dr. Todd. Santa Rosa, CA 95404
How about them using an exercise ball?