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Why ergonomic chair adjustments matter

The number of adjustments on ergonomic chairs can seem confusing. Here's help! What do all those adjustments do and why?

Every person is different. No two bodies are the same, even ones that are the same height.

We have different thigh and shin lengths, deep or shallow lumbar curves, long or short spines, and so on. Our working habits and habitual postures vary too, and we might have an injury.

This is why we need to adjust our ergonomic chairs to suit our needs.

Seat height adjustment

This allows you to adjust the height of the seat of the chair so your arms are at the right level to use your keyboard and mouse to achieve a suitable position. You'll then reduce the risk of strain or joint problems. Having your forearms parallel to the desk top is ideal.

Once at the right height for your arms, you also need to ensure your feet are firmly supported by the floor or a footrest.

Consider using a height-adjustable desk too, to help position yourself at the right height without the need for a footrest.

Seat depth adjustment

Adjust the seat depth on your ergonomic chair by moving the seat forwards or backwards to provide the correct support for your thigh length.

Sit back on the seat pan to enable your back to be supported by the chair's backrest.

People shorter in the thigh might make the mistake of perching forwards on the seat so not gaining getting support from the backrest. Try to avoid this because it's fatiguing and compromises your natural posture.

If you are long in the thigh, increase the chair's seat depth. Because if the seat is not long enough for you, this can lead to poor pressure distribution and increased pressure on some areas of the back of the thighs.

Seat tilt angle adjustment

This allows the seat to be able to be tilted forward slightly, helping you achieve a more neutral pelvis tilt and improved posture. This reduces muscle activity and pressure on the discs.

It helps to avoid your pelvis from rotating backwards and creating a slouched posture.

Backrest angle adjustment

Adjusting the backrest angle helps your ergonomic chair to provide suitable support to your back for the tasks you are doing.

Adjust the backrest angle to be just off upright, and rest your back against the backrest.

When you're not using your keyboard and mouse, for example on video calls, you could recline your ergonomic chair's backrest more, to take more of the weight of your upper body. This then reduces the pressure on discs and reduces muscle work.

It's important that the lumbar curve is maintained and your pelvis does not rotate back when you tilt your back rest, which would create a poor slouching posture, so don't tilt too much!

Whole chair tilt

Some ergonomic office chairs recline whilst maintaining the angle between the back and the legs and thus the spinal position. This can reduce the pressure on discs and muscles, allowing you to relax and reduce strain.

There are two types of tilt action on an ergonomic chair;

  • A tilt that pivots from the central point under the seat. Your feet will come off the floor as you recline.
  • A knee tilt where the pivot is closer behind the knees, foot lift is negligible and your back and head will descend more than a central pivot. This allows movement without losing support.

Lumbar support height adjustment

Most good ergonomic chairs have gentle shaping of the backrest to fit the inward curve of your lower back. Some also have additional adjustable supports built in. The aim of lumbar support is to provide support and help prevent slouching when sitting (caused by the flattening of the lumbar spine).

Ergonomic office chairs usually have one of the following two options:

  • The whole backrest can be adjusted in height, therefore fitting the curve of the backrest to your curve (shown in this picture).
  • Change the height (and potentially the depth) of the lumbar support on the backrest to suit.

Lumbar support size and amount

How much support would you like in the lumbar region from your chair? You might have the ability to adjust the size and amount of support that a lumbar support gives your lower back, to suit your preference and body shape.

Armrest height adjustment

Adjusting the height of your ergonomic chair's armrests so they are just under your elbows will support the weight of your arms when you're not typing. Your arm and shoulder girdle muscles can then rest.

Armrests can also be beneficial when using your mouse by supporting your arm and keeping the mouse close to your body.

Can problems arise if a chair's armrest is not adjustable? Yes, the armrests can hit the edge of the desk, stopping you from positioning yourself close enough to the desk. This would encourage you to key and mouse with your arm forwards, or perch on the front of the chair receiving no back support.

Armrest width adjustment

Adjusting how far apart the armrests are on your ergonomic office chair helps you ensure there is room for your arms to rest on the arm rest without feeling restricted.

By the way, armrests that are too far from your body can cause splayed elbows, which in turn can create shoulder tension and affect your wrist position when typing.

Headrest height adjustment

You'll likely only use a chair headrest when you're slightly reclined in the chair. Adjust the height of a chair's headrest so that it feels comfortable when you lean on it for support for your head.

A head or neckrest on an office chair may be useful if you do a lot of tasks where you are not using your keyboard and mouse and are able to recline. Equally if you have neck and shoulder problems, taking regular reclining breaks could allow the muscles in this area to relax.

Chairs shown in illustrations are the Bimos and RH range of ergonomic chairs from Posturite.