Ergonomic office furniture ... |
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Ergonomic workstations
Workstation set up A second, somewhat common size adjustment is seat depth. The primary concern with seat depth is to provide a maximum amount of surface area on which to distribute the body weight, while being certain that the delicate area inside the knee is kept clear of potential contact stresses, such as pressure from the front of the seat. As a general rule, when sitting with your back properly supported by the backrest, there should be approximately 2 to 4 inches of space between the front of the seat cushion and the inside of your knee. A third, less common size adjustment is backrest height. As with seat depth, the idea of adjustable backrests is to maximize surface contact and minimize pressure points. While the curvature of people’s backs, particularly the curvature of the lumbar area of the spine, varies somewhat from person to person, it is the position of the curvature that matters. Therefore, a contoured and height-adjustable backrest can offer exceptional lumbar support while maximizing surface contact and weight distribution. 3) Recline is healthy. As mentioned above, your mom wasn’t passing along the best information when she told you that sitting up straight is good for you. Today, researchers everywhere agree that recline is healthy. As renowned industrial designer and human factors expert Niels Diffrient said, “The more you recline, the more comfortable you get. Ergo, the best chair is a bed.” Essentially, the more work you can perform while reclining, the more of your body weight will be distributed to the backrest of your chair, and the less pressure your spine will have to endure (See Fig. 3). However, extended recline can put additional stress on your neck and shoulders as they work to maintain the upright position of your head. Therefore, it’s wise to consider a chair with headrest if you expect to perform extensive work in a reclining position. 4) Armrests should be adjustable and kept level. Many chairs today offer adjustable armrests, which are critical because different tasks and different sized users require different armrest positions. However, since most of these chairs have independently adjustable armrests, users are free to set the right and left arms at different heights. This is fine for specific tasks, but becomes a problem and a danger if the user doesn’t adjust them back to level. A common choice is to keep the armrest on the mousing side lower than the other armrest. Such users will sit, potentially for years, with a crooked spine. And as we know from Ergonomic Principle #3, that’s a high-risk posture for injury. Again, according to the Liberty Mutual Insurance Company, low-back pain MSDs account for 15% of all Liberty Mutual workers’ compensation claims and 23% of the costs associated with those claims. A properly used ergonomic chair will greatly reduce the risk of low-back pain and injury and their attendant costs. Creating a Healthy Workstation by Rhonda Crenshaw, Director of Humanscale’s National Ergonomic Group
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