A kneeling chair is a type of chair for sitting in a position with the thighs dropped to an angle of about 60 to 70 degrees from vertical (as opposed to 90 degrees when sitting in a normal chair), with some of the body's weight supported by the shins. The original kneeling chair was the Balans chair, which was developed in 1979 by Hans Christian Mengshoel and the designers Oddvin Rykken, Svein Gusrud and Peter Opsvik.
The intended purpose of a kneeling chair is to reduce lower back strain by dividing the burden of the weight to the knees as well as the buttocks. People with coccyx or tailbone pain resulting from significant numbers of hours in a sitting position (e.g., office desk jobs) are common candidates for such chairs. However, it is not proven that kneeling chairs are an optimal solution.
A proper kneeling chair creates the open body angle by lowering the angle of the lower body, keeping the spine in alignment and the sitter properly positioned to task. The benefit of this position is that if one leans inward, the body angle remains 90 degrees or wider. A misconception regarding kneeling chairs is that the body's weight bears on the knees, and thus users with poor knees cannot use the chair. In a proper kneeling chair, some of the weight bears on the shins, not the knees, but the primary function of the shin rests (knee rests) are to keep one from falling forward out of the chair. Most of the weight remains on the buttocks. Another way to keep the body from falling forward is with a saddle chair. This type of seat is generally seen in some sit stand stools, which seek to emulate the riding or saddle position of a horseback rider, the first "job" involving extended periods of sitting.
Academic studies 
Ericson and Goldie studied spinal shrinkage in subjects using three different types of chairs while performing video display unit work and, in an eight-person study, found that subjects shrank more when sitting on a forward sloping chair with knee support than on a conventional chair.
Drury and Francher studied the original Balans kneeling chair in 1985, concluding that overall it was "no better than conventional chairs and could be worse than well-designed conventional office chairs." Lander et al. conducted another experiment in 1987 comparing the kneeling chair with a conventional chair and concluded that their experimental data "do not support the manufacturer's claim that the Balans chair is likely to decrease complaints of [lower-back pain]".
A 1989 study on a sample of 20 subjects concluded that the Balans chair promoted greater lumbar curvature than the "straight back chair" during relaxed sitting, typing and writing and that it could contribute to treatment of lower back injuries. A more recent study from 2008 confirms that "ergonomically designed kneeling chairs set at +20 degrees inclination do maintain standing lumbar curvature to a greater extent than sitting on a standard computer chair."
-  The Federation of Norwegian Industries about original Balans
- Diane Burley (Undated). "Peter Opsvik". Pure Contemporary.com. Retrieved 18 March 2011.
- "Kein Tod, kein Leben" [No Death, No Life] (in German). Der Spiegel. 3 June 1991. Retrieved 18 March 2011.
- Sigrid Rømcke Thue (Undated). "Peter Opsvik". Store norske leksikon (in Norwegian). Institusjonen Fritt Ord. Retrieved 18 March 2011.
- Hard Facts About Soft Machines: The Ergonomics Of Seating. Google Books. Retrieved 2012-10-17.
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- Ericson, M.; Goldie, I. (1989). "Spinal shrinkage with three different types of chair whilst performing video display unit work". International Journal of Industrial Ergonomics 3 (3): 177. doi:10.1016/0169-8141(89)90017-6.
- Drury, C. G.; Francher, M. (1985). "Evaluation of a forward-sloping chair". Applied ergonomics 16 (1): 41–47. doi:10.1016/0003-6870(85)90145-0. PMID 15676532.
- Lander, C.; Korbon, G. A.; Degood, D. E.; Rowlingson, J. C. (1987). "The Balans chair and its semi-kneeling position: an ergonomic comparison with the conventional sitting position". Spine 12 (3): 269–272. doi:10.1097/00007632-198704000-00014. PMID 2954222.
- Bennett, D. L.; Gillis, D. K.; Portney, L. G.; Romanow, M.; Sanchez, A. S. (1989). "Comparison of integrated electromyographic activity and lumbar curvature during standing and during sitting in three chairs". Physical therapy 69 (11): 902–913. PMID 2813518.
- Bettany-Saltikov, J.; Warren, J.; Jobson, M. (2008). "Ergonomically designed kneeling chairs are they worth it? : Comparison of sagittal lumbar curvature in two different seating postures". Studies in health technology and informatics 140: 103–106. PMID 18810008.