Office Ergonomics: The Chair
Other Topics: Mouse and Pointers | Keyboard Tray | Monitor and Copyholder
This fact sheet provides helpful information on using and purchasing office chairs. Adjusting your chair to better fit your body and your workstation will help make you more comfortable and productive, and may help prevent injury.
What do I need to know to adjust my chair?
- • Before making any adjustments to your chair,
you should receive clear, hands-on training on the proper use of the chair.
You should also review the manufacturer's instructions to learn about the
chair's features and possible adjustments.
- • Use the guidelines below to make adjustments
on your chair. Most chairs will have some but perhaps not all of these
features.
- • Once you have adjusted your chair, you'll be ready to adjust the height of your working surface (see Office Ergonomics: The Keyboard Tray).
Chair Height Adjustments
- • Adjust chair height so your feet are
comfortably flat on the floor with thighs roughly parallel to the floor.
- • Feet that dangle from chairs are uncomfortable and may lead to numbness and tingling in the legs. Use a footrest if needed.
Seat Pan Adjustments
- • The seat pan is the surface you sit on.
- • Some chairs can be adjusted for depth,
allowing the seat pan to slide forwards or backwards.
- • Adjust the seat depth so your back
comfortably leans against the backrest and your thighs are fully supported,
but the front of the seat does not press into the back of your knees.
- • If the seat pan touches the back of the knees
it may be uncomfortable and lead to numbness and tingling in the legs.
- • Some chairs also offer tilt adjustment of the
seat pan.
- • Release the seat tilt lock to allow you to
rock (free-floating position).
- • Use the tension knob to adjust the resistance
of the rocking motion to your comfort. Rocking is helpful in changing pressure
points when relaxing, but should not be used while typing.
- • Keep the seat pan close to horizontal (no
tilt) when in a locked position.
- • Lock the seat pan when typing, to provide solid, non-moving back support
Back Rest Adjustments
- • Adjust height of back support to place the
lumbar bulge in the curved area of your lower back (small of the back).
- • Adjust lumbar bulge to your comfort. A small
pillow can be added if the lumbar bulge is too small.
- • Avoid sitting up straight. It is generally better and more comfortable to sit slightly reclined by adjusting the tilt of the back support.
Arm Rest Adjustments
- • Adjust the height of the armrests to support
your shoulders in a relaxed position, without hunching or raising them.
- • Ideally, armrests should adjust for width and/or pivot. Move the armrests comfortably close to the body so that your upper arms are next to your body.
What is the best working posture?
There is no ‘one best' posture. In fact, maintaining a single posture for long periods of time puts stress on your body. Good working postures keep your body in a balanced position without twisting, bending, or reaching. Ideally, it is best to also perform some portion of computer work from a standing position. (This would require a sit-stand workstation, with fully height-adjustable work surfaces or components).
Even when working comfortably, it is important to routinely take breaks that involve different muscle groups and remove the eyes from a monitor screen. One minute “mini-breaks” (during which you might close your eyes, breath deeply, stretch, and be aware of your body and its position) may help protect against fatigue and can lower stress levels.
What should I look for when purchasing an office chair?
- • Comfort. The seat pan and back support should
be made of high-density foam, gel, or a comfortable mesh alternative, with a
soft, curved seat front. Avoid strongly molded lumps and depressions; these
seats fit only a limited range of sizes.
- • Pneumatic seat height adjustment that can be
easily changed with a lever by the user.
- • Seat pan depth adjustment; the seat or the
back support moves front to back.
- • Back support with:
- Adjustable height
- Adjustable tilt with a tension adjustment to
balance body weight.
- Adjustable lumbar support profile (i.e., depth of the lumbar bulge).
- • Well-padded armrests that are adjustable both vertically and horizontally.
- Armrests must be small enough so that they do not
hit the keyboard when pulled close.
- If armrests are adjusted for horizontal position from under the seat, make sure that seat pan widths come in several sizes to accommodate small and large employees.
- • A base with at least 5 feet equipped with
castors
- • Castors that are matched to the floor
surface—higher resistance for tile, lower for carpet.
- • Extreme use situations:
- For 2- or 3-shift work organization, select a chair
designed for 24-hour use.
- For very large or heavy workers, select a chair
designed to support extra weight.
- Very slim or wide workers may require an extra
narrow or wide seat pan for comfortable support and to allow proper
horizontal armrest adjustment
- Very tall or very short workers may require a
different cylinder to properly adjust the height of the chair.
- If the worker is injured, consult a knowledgeable health professional for specific requirements.
