I sit on my computer chair for around thirteen hours a day, and it leans further back than the chairs I had in school and whatnot. I thought it was a malfunction of the chair, but even if it is, that malfunction could be saving my back in the long term.
Over on ScienceDaily there is an article that talks about how research has been done on the spine showing that sitting up straight at 90 degrees could do more harm to your back than leaning at around 135 degrees.
“A 135-degree body-thigh sitting posture was demonstrated to be the best biomechanical sitting position, as opposed to a 90-degree posture, which most people consider normal,” said Waseem Amir Bashir, M.B.Ch.B., F.R.C.R., author and clinical fellow in the Department of Radiology and Diagnostic Imaging at the University of Alberta Hospital, Canada. “Sitting in a sound anatomic position is essential, since the strain put on the spine and its associated ligaments over time can lead to pain, deformity and chronic illness.”
It will be interesting to see if this change actually takes hold in popular society, but if nothing else, at least now you are informed. So lean back a little bit, it’s good for you.