Choosing The Right Ergonomic Chair

Choosing ergonomic chairs for your team can be difficult, particularly if you are looking to fit out an office from scratch and have staff of various shapes and sizes.

Each individual will have different requirements, depending on their physical dimensions, work tasks, workspace design and personal preferences.

Here’s a quick overview of the main features of task chairs to help you make the right decision.

Backrest Height 

The height of the backrest determines how much of the back is supported. Generally speaking, a chair that provides support, at least to the level of the shoulder blades is recommended for most users, although it is also a matter of personal preference.

Mid back: provides support to below the shoulder blades 

High back: provides support up to the shoulder blades 

Extra high back: provides upper back support and may include a headrest for head support. 

Backrest Shape

The shape of the backrest is usually either square or oval and is largely an aesthetic choice, dependent on personal preference. Slome back.

Lumbar Support

Arguably the most important feature of the chair is the lumbar support, the curved part of the backrest that supports the lower back. The lumbar support should at least be height adjustable.  Some chairs also offer depth adjustment on the lumbar support that enables the user to adjust the lumbar support to the correct depth while seated.

Seat Size

This refers to the width and depth of the seat pan. There should be a gap of approximately the width of 3 fingers between the front edge of the seat and the back of the knees when the user is sitting in contact with the backrest.

If the seat is too deep, it will make contact with the back of the user's knees and potentially lead to discomfort and circulation issues. It can also cause the user to sit on the front edge of the chair resulting in a loss of back support. If the seat is too short, the user's weight will not be evenly distributed, causing increased pressure on the back of the thighs and creating the sensation of sliding forward in the chair.

You should also consider the width of the seat. If the seat width is not wide enough the user can hang off the side of the chair creating pressure points.

Backrest Tilt Mechanism

Traditional ergonomic chairs have an independent tilt mechanism that allows the user to adjust the angle of the seat and the backrest independently from each other.  This mechanism is most often recommended by Occupational Health professionals for users with back conditions that require particular locked sitting postures. 

More recently, chairs are being produced with a ‘dynamic’ swing mechanism that allows the user to move the backrest backwards and forwards when seated. Typically, users can set a level of tension to control how far and how easily the backrest can tilt and some designs allow the user to lock the chair at certain angles. 

If choosing a dynamic mechanism, care should be taken that the swing motion is adjustable and comfortable for the user, and most importantly, that the backrest can be locked in a supportive position.  

Armrests 

Most Physiotherapists do not recommend armrests on chairs as they can tend to prevent the user positioning their chair close to or under the desk. In some circumstances, armrests can be useful, particularly if the desk surface is limited and additional forearm support is needed.  If you’re considering armrests make sure they are height adjustable or removeable.

Seat Height

Your seat height should be adjustable to suit the height of the desk you will be using. Chairs can often be fitted with different gas lift mechanisms to accommodate different height requirements of the user. If your desk is higher you may require a high lift, or vice-versa. Remember that you may need a footrest if raising the chair to the optimum height for good posture, leaves your feet off the ground.

Castors 

Ergonomic chairs usually have a stable 5-castor base. Most office chairs will come with a standard carpet castor fitted for use on carpets. You can also fit soft castors for hard floor surfaces and castors that will lock or unlock with release or application of pressure from the user’s body weight.

Seat Material & Construction

The seat should be constructed from long-wearing, high density foam. Some chairs will have a moulded foam shape, make sure this shape feels comfortable and fits your bottom shape. Other chairs will have a flat foam, allowing the seat to mould to you. Modern technologies such as memory foam and gel seats will allow the seat to adapt and change for each individual user.

Mesh or Upholstered?  

Occupational Health professionals tend to recommend upholstered style chairs with medium to high back rest and good lumbar support for the majority of users. Mesh chairs are a modern variant in seating, preferred by designers for their slim back design and stylish looks, however, they often lack adjustability of upholstered chairs. Mesh chairs must have an adjustable lumbar support to be considered ergonomic. 

In Summary

• Measure the height of your worksurface and check that the height range of your chair is adequate

• If you choose a chair with a dynamic backrest, make sure it can also be locked at your preferred position

• Choose the correct castors for the type of floor in your workspace

• Choose upholstered over mesh designs 

• Avoid armrests or make sure they can be lowered to fit underneath the worksurface

• If you have a sit-stand desk, consider a seat that can also function as a sit-stand stool