The human body evolved as a long distance runner. Our bodies are not adapted to sitting for eight hours a day in a fixed position. In fact, if a person tries consciously to sit with his back supported by his internal muscles he will usually be exhausted after a few minutes. This is the reason for office chairs.
When it is considered that ordinary office workers are expected to sit before their computers for about eight hours per day it becomes apparent that sitting in such a position for such a long period either demands great physical strength or that the body must compensate in some way to relieve the muscular strain that is involved.
Sitting in one position for more than a few minutes is almost impossible because it entails holding a very unnatural position. So office workers shift about, twisting and turning almost as if being tortured but without knowing it. The strain on the spinal column can be considerable.
The spine is a series of bones stacked upon each other and cushioned by soft tissue. The four regions of the spine are the neck, the chest, the lumbar region and the pelvic area. The vertebrae can easily get out of alignment when unnatural position are adopted for lengthy periods. As a consequence nerves can be pinched resulted in transferred pain or dull aches.
An important feature of an industrial chair is the backrest. This should be padded and curved so as to support the lumbar region of the spine. However, every back is slightly different so the angle of the backrest can be adjusted to suit the particular person using it.
Casters at the base of office chairs enable them to be pushed about easily. The importance of this is that the distance between the edge of the desk and the worker’s body has an important effect upon the strain placed on the spine. Another important aspect of the casters is that they allow a worker to push herself away from her desk before rising by straightening her knees. This is really important because many backs can be suddenly twisted out of joint in the act of rising, or sitting.
Another important consideration for people who sit all day is the height of their seat from the floor. This has to be related to the height of the desk and the ways in which the arms must be angled over key boards. When the body is positioned correctly in between the chair and the work station a person may be comfortably situated to be productive from one day to the next. This illustrates the importance of office chairs in any industrial environment.