Computer Work-Station: Chair Ergonomics
A properly designed and adjusted chair will
provide appropriate support to the back, legs, buttocks, and arms. This support can
reduce contact stress, over exertion, and fatigue. It will also promote proper
circulation to the extremities. The following items are critical toanyone who spends
extended hours at the work-station:
The proper adjustment of the chair is related to the proper
placement of the monitor, keyboard, mouse, and work surface.
- Improper size, shape, or choice of materials for the seatpan
and backrest may result in uneven weight distribution, contact stress,
decreased circulation to the extremities, and awkward posture.
- The seat and backrest of the chair should support a comfortable posture
that allows frequent changing of the seating position (Fig. 1).
Adjustable chair and backrest.
Seatpan with a rounded,
- The seatpan should accommodate the specific employee
(not too big/small). It should be padded and have a rounded, "waterfall" edge
(Fig. 1). This will reduce contact stress to the back of the legs.
- The angle of the seatpan is also important. A seatpan with
an adjustable tilt ensures the worker is able to maintain proper support in
- Chairs should be height adjustable, especially in work
areas where they are shared by a number of employees.
- The chair height is correct when the entire sole of the foot
can rest on the floor or a footrest (Fig. 2), and the back of the knee
is slightly higher than the seat of the chair (Fig. 3). This position allows
blood to circulate freely in the legs and feet.
Fig. 2 Footrest.
Knee slightly higher than the seat of the chair.
- Armrests that are too high or too low can produce awkward
postures, create contact stress to the elbow, provide inadequate support,
and may prevent the operator from moving close enough to the work-station.
- Adjustable armrests (Fig. 4) can be lowered to fit
under work surfaces. This allows the user to work from a comfortable
- The armrests should support both forearms while the employee performs
tasks and should not interfere with movement.
Office chair with
For more about office ergonomics, please see the following articles:
Portions of the above information
has been provided by the Occupational Safety & Health Administration
Last Editorial Review: 7/6/2004