Features of an Ergonomic Chair

In order to help make sure you choose a chair with all the necessary adjustments, we will break

the chair down into components:

I. Casters and Base

Use a chair with casters and a 5-point base to ease movement and minimize possible

tipping. Generally, nylon carpet casters are standard, but soft wheel casters are available

for hard surfaces such as linoleum. Rubber locking casters are useful on stools to prevent

tipping.

II. Seat Pan

The seat pan is the component of the chair that supports the majority of the user’s weight.

It is important to purchase a chair which uses dense, small-cell foam padding or spring

coils to retain its support and cushioning (this usually involves purchasing a chair over

$250.00). The front part of the seat should slope down slightly (waterfall design) and

allow a fist size gap between the back of the knees and the front edge of the seat pan to

reduce pressure at the back of the thighs. Tilt adjustments are preferred to allow a slight

forward or reclined working posture to be attained. A seat pan with a sliding mechanism

is also a beneficial feature. This allows small and tall users to adjust the distance from

the back rest.

III. Backrest

Adequate lumbar support is the most crucial element of a backrest. The backrest should

either be small enough to fit into the small of the back, clearing the pelvis and back of the

rib cage, or curved to provide adequate support. Many chairs come with a built-in lumbar

adjustment which can be adjusted by turning a knob on the back of the chair and then

raising the backrest to a comfortable position. Inadequate lumbar support places excess

pressure on the spine. Remember, a lumbar support cushion properly placed with the

fullest part of the support behind the small of the back (belt-line) can help to accentuate

lumbar support. The backrest should also have angle, in-out, and height adjustments to

achieve proper spinal alignment. The angle adjustment allows the user to adjust the angle

of the back rest relative to the seat pan, as opposed to the tilt mechanism, which moves

the seat pan with the backrest. When you change the tilt, the angle between the seat pan

and the backrest stays the same.

IV. Armrests

Height and width adjustments are absolutely necessary when purchasing a chair with

armrests. The armrest should be made of a soft material and should be at least 2" wide to

provide adequate surface area.

V. Seat Height

Almost all task chairs come with a hydraulic seat height adjustment. This is probably the

single most important adjustment mechanism on a chair. It allows the user to adjust the

chair so their feet can rest properly on the floor or footrest and the upper body is properly

aligned with the computer monitor and input devices such as the keyboard and mouse.

VI. Chair Recline or Tilt

The chair recline or tilt adjustment changes the angle of the entire seat relative to the

floor. As with backrest angle adjustability, a reclined chair transfers some of the upper

body weight to the backrest of the chair. It is also important that the user change body

positioning throughout the day.

It is always important to try out or “test-drive” a chair before you purchase a chair in

order to determine individual comfort.