Sitting



Sitting is a rest position supported by the buttocks or thighs where the torso is more or less upright. There are several ways for humans to sit.

Sitting on the floor
The most common way of sitting on the floor involves bending the knees. One can also sit with the legs unbent, using something solid as support for the back or leaning on one's arms.

Sitting with bent legs can be done along two major lines; one with the legs mostly parallel and one where they cross each other. The parallel position is reminiscent of, and is sometimes used for, kneeling. The latter is a common pose for meditating.

Parallel legs

 * Seiza (正座, literally "correct sitting") is a Japanese word which describes the traditional formal way of sitting in that country. Sitting in seiza is kneeling on one's own lower legs, with the feet under the buttocks, toes pointed backwards.  To sit in seiza for any length of time requires careful positioning of the heels under the sit bones of the hip, to minimize circulation loss.


 * Squatting involves resting one's weight on the feet and usually also the buttocks and the backs of the thighs. Squatting is sometimes considered a form of standing, because the weight of the body is supported by the feet rather than the buttocks; however, a full squat resting the buttocks on the backs of the ankles relieves the muscles of the legs. Squatting (including the use of the squat toilet) is more common in Asian cultures.



Cross-legged

 * The position known as Indian or tailor style involves both feet bent inwards and under the body, crossing each other at the ankle.
 * The lotus position involves resting each foot on the opposite thigh so that the soles face upwards. If only one foot is brought into this position, it is called a half-lotus position. This position is common in yoga and meditation.
 * The Burmese position, named so because of its use in Buddhist sculptures in Burma, places both feet in front of the pelvis with knees bent and touching the floor to the sides. The heels are pointing toward pelvis or upward, and toes are pointed so that the tops of the feet lay on the ground.  This looks similar to the cross legged position, but the feet are not placed underneath the thigh of the next leg, therefore the legs do not cross.  Instead, one foot is placed in front of the other. This  is a popular sitting alternative for those less comfortable with the use of the Lotus or half Lotus positions in meditation and yoga.

Zazen, the Japanese word for "sitting meditation", is a form of meditation rather than a particular posture. During zazen, practitioners may assume a lotus, half-lotus, Burmese, or seiza position.

Sitting on a raised seat
Most raised surfaces at the appropriate height can be used as seats for humans, whether they are made for the purpose, such as chairs, stools and benches, or not. While the buttocks are nearly always rested on the raised surface, there are many differences in how one can hold one's legs and back.

There are two major styles of sitting on a raised surface. The first has one or two of the legs in front of the sitting person; in the second, sitting astride something, the legs incline outwards on either side of the body.

The feet can rest on the floor, or on a footrest, which can keep them vertical, horizontal, or at an angle in between. They can also dangle if the seat is sufficiently high. Legs can be kept right to the front of the body, spread apart, or one crossed over the other.

The upper body can be held upright, recline to either side or backwards, or one can lean forward.

Posture
For years, children have been taught to "sit up straight" in their chairs. It was believed that a straight back (at 90 degrees with the legs) was the best posture, but recent studies show that sitting upright for hours causes increased stress on the back, and may be a cause of chronic back problems.

Researchers have found that a "135-degree back-thigh sitting posture" was the best posture to avoid back problems&mdash;that is, leaning back in the chair 45 degrees. Researchers found that the 90-degree position contributed most to strain on the spine, while the 135-degree position was the most relaxed. The research does not, however, propose that slouching forward is a good alternative to sitting upright.

Variations
Variations of the above, such as an aside variant with the legs resting above and beside the armrests (example), or the anti-authoritarian posture of reversing the chair and one's legs in front of the back of the chair.

Kneeling chairs
Kneeling chairs (often just referred to as "ergonomic chairs"), encourage better posture than conventional chairs and they look quite different. To sit in a kneeling chair one rests one's buttocks on the upper sloping pad and rests the front of the lower legs atop the lower pad, i.e., the human position as both sitting and kneeling at the same time.

Kneeling chairs should not, in fact, be called "ergonomic" chairs because they go against what ergonomists recommend as a sitting position which reduces the risk of musculoskeletal injuries. Since the body is one long kinetic chain, prolonged sitting can lead to musculoskeletal injuries in any joint. "Neutral" sitting postures&mdash;postures that reduce the demands on the body&mdash;involve sitting fully back in a chair's seat pan and using the back rest for support. It is impossible for humans to sit unsupported for long periods of time and maintain neutral postures, nor is it advisable to try. Avoid using kneeling chairs as well as exercise balls for prolonged sitting.

In mythology
In various mythologies and folk magic, sitting is a magical act that connects the person who sits, with other persons, states or places where he/she sat.

General references

 * Clear demonstrations of the various position
 * Ergonomics of sitting postures and seating
 * Sitting straight "bad for backs"