What Is a Knee Chair?

Conventional office chairs may cause back problems with long-term use.

Kneeling chairs, sometimes called knee chairs, are a special type of ergonomic seating that encourages users to maintain better spinal position, reducing strain on the lower back and pain in the tailbone. First developed in the late 1970s as the "balans" chair, by Peter Opsvik, these chairs are now available from a number of brands and manufacturers. For some users, they provide better day-to-day ergonomics than conventional office chairs, but they do have some drawbacks.

Structure

Kneeling chairs are constructed with a seat and knee or shin rest and sometimes a back support. The slanted seat encourages users to sit with their thighs dropped to about a 60- to 70-degree angle as opposed to the 90-degree angle encouraged by conventional chairs. The chair supports some of the body's weight on the shins but maintains most of the weight on the seat. Kneeling chairs encourage an open body position even when leaning forward.

Benefits

According to the Canadian Centre for Occupational Health and Safety (CCOHS), kneeling chairs provide proper spinal alignment and make short-term sitting significantly more comfortable. They are most beneficial when correctly fitted to the user. According to Studies in Health Technology and Informatics, ergonomically-designed kneeling chairs set at a 20-degree or greater inclination from the horizontal encourage users to maintain a better standing lumbar curvature than conventional seating.

Drawbacks

Kneeling chairs place weight on the shins and can over flex the knees and ankles. Depending on the design of the chair, it may limit the available number of sitting positions, causing earlier fatigue. Like other chairs that tilt forward, knee chairs may cause clothing to ride up. They can also be difficult to get into or out of and can reduce the range of the user's reach.

Considerations

Kneeling chairs don't provide the same health benefits for every user and tend to be more effective when fitted to the person who will sit in them. According to the International Journal of Industrial Ergonomics, workers sitting in kneeling chairs actually suffered from slightly more spinal shrinkage when using a kneeling chair than they did in a conventional chair. "Applied Ergonomics" reported that some users complained of greater discomfort in this chair type than in a conventional chair. CCOHS recommends using forward-sloping chairs, saddle chairs or a sit-stand seat for jobs or users where kneeling chairs are inappropriate.

References

• Pure Contemporary: Peter Opsvik
• "International Journal of Industrial Ergonomics"; Spinal Shrinkage with Three Different Types of Chair Whilst Performing Video Display Unit Work; Mats O. Ericson; April 1989
• Canadian Centre for Occupational Health and Safety: Alternative Chairs
• "Studies in Health Technology and Informatics"; Ergonomically Designed Kneeling Chairs -- Are They Worth It?; J. Bettany-Saltikov et al; 2008
• "Applied Ergonomics"; Evaluation of a Forward-Sloping Chair; C.G.Drury et al; March 1985