Since most office workers use computers today, chairs need to support the entire body and promote good posture with minimal strain or risk of repetitive stress injuries, especially if you sit typing for long periods. Ergonomic office chairs are fully adjustable, with levers, knobs and buttons to alter height, depth and tilt so anyone can sit in them comfortably and safely.
Height
Consider the work surface when determining proper seat height. Ideally, the seat pan should be just below your knees, typically about 16 inches from the ground. When seated, your arms should extend straight out from the elbows to reach the work surface, with your feet firmly on the floor. If the desk is too high and nonadjustable, raise the seat and use a footrest. There should also be enough room between your chair and the desk for you to cross your legs. A pneumatic adjustment lever is usually under the seat. Stand in front of the chair, raise the seat, then push it back down until the seat pan is the proper height.
Seat Pan
The seat pan usually has a button, lever or crank on the underside, allowing you to tilt it up or down about 5 degrees so you can adjust it to support your thighs. Some seat pans slide backward and forward so you can adjust the depth. The front of the seat pan should end about 2 inches from the back of your legs.
Backrest
The backrest should be at least 15 inches high, curving outward at the bottom. While sitting in the chair, adjust the backrest forward and vertically--usually with a knob or buttons located on the sides or under the backrest column--so the backrest's curve fits into your lower back while you sit up straight.
Some backrests recline anywhere from 15 to 30 degrees. A chair that steeply reclines should have a headrest.
Armrests
Armrests used to be rare for typists because they kept the chair from getting close enough to the keyboard. But many of today's chairs have 10-inch armrests that give typists a place to rest without being an obstacle.
Armrests should be 7 to 10 inches higher than the seat pan and wide enough so your forearms rest at a 90-degree angle to your upper arms. Your elbows should not be raised; it causes shoulder strain. If the armrests are too high, remove them. The distance between the armrests should be at least 16 inches so the seat is not too tight.
Construction
Any chair should have a sturdy base with five legs on wheels or casters that roll smoothly. The chair should swivel 360 degrees so you don't have to stand to reach items in other parts of your workspace.
Tags: about inches, about inches from, chair should, inches from, least inches