The Ergonomics of a Chair Explained

The average adult spends over 9 hours a day sitting, yet many of us don’t consider how our chairs impact our health and productivity. Prolonged sitting, especially in poorly designed chairs, can lead to discomfort, back pain and even serious musculoskeletal disorders. That is where ergonomics comes into play. We will guide you through the concept of ergonomics, focusing on how ergonomic office chairs can transform your work experience. We’ll also cover the key features of ergonomic chairs, how to sit correctly and how ergonomic chairs reduce health risks.

What Does the Term ‘Ergonomic’ Mean?

The term “ergonomic” refers to the scientific application of psychological and physiological principles in a working environment. It focuses on designing furniture, equipment and environments that create comfort and productivity in the workplace. 

For instance, your office chair can be ergonomically designed for maximum comfort and safe human interaction. This helps the body by correcting posture, reducing pain and introducing long-term health benefits.

What is the Aim of Ergonomics?

Ergonomics aims to improve the safety and well-being of people in their working environment by designing workspaces and tools to fit the human body. It aims to:

• Reduce injuries: Such as back pain and musculoskeletal disorders
• Increase productivity: Improving overall comfort and pain boosts productivity 
• Improve well-being: Ergonomics aims to improve overall well-being

What Makes a Chair Ergonomic?

The features of an ergonomic office chair offer corrective support by being fully adjustable. Seat height, depth and angle are all vital to enhance the suitability of a chair and provide complete comfort. As such, the backrest should have height and tilt mechanisms, the lumbar should be inflatable and the arms should be adjustable.

In addition, choosing an adjustable office chair is vital if the chair is intended for use by multiple people of different body types. 

As ergonomics has advanced, chairs are now designed to meet the specific needs of different users. For example, if you experience back pain, ergonomic chairs with built-in lumbar and thoracic support can provide targeted relief. Similarly, ergonomic office chairs are tailored for users of varying heights and builds, offering petite options for smaller individuals and larger chairs for taller users. These comprehensive ergonomics of a chair will provide efficient support throughout the working day.

The Ergonomics of a Chair Explained

Seat Height

The ergonomics of a chair start with seat height. It should allow you to place your feet flat on the floor, which is essential to maintain correct positioning for your feet, legs and hips. As most work desks have a fixed height, it’s also important to have an adjustable office chair that can be altered to suit you and your workstation.

Seat Width and Depth

Seat depth is important to allow you to fully engage with and be supported by the backrest. When sitting upright with your back to the backrest and your bottom to the back of the seat, there should be at least an inch between the edge of your seat and the back of your knees. 

If your seat is too far forward, it may put undue pressure on the back of your knees, preventing the backrest from supporting you. Alternatively, if the seat is too far back, your thighs will not be supported. 

Seat Tilt

A seat tilt allows for the correct positioning of the pelvis and neutral alignment of the lower back and lumbar region of the spine.

Anterior pelvic tilt is a posture issue that affects almost everyone who spends most of their workday sitting. It is vital to keep the pelvis in a neutral position when sitting, with 80-degree angles at the hips, knees and ankles (with your knees slightly lower than your hips).

Backrest Lumbar Support

An adjustable backrest will allow users to align the curve in the chair with their spine for optimal support. Furthermore, the height adjustment of the backrest allows for correct lumbar support and back contact. An inflatable lumbar is ideal to alter the pressure and support your lower back. 

The support given to your lower back is an essential feature of the ergonomics of a chair. Most issues are found in the lower back, made worse by an unsupportive chair. Ergonomic chairs support the natural ‘S’ shape of the spine, preventing slouching and reducing stress on the spine and pelvis.

Backrest Tilt or Recline

The backrest tilt should be easily accessible from your seated position and include ‘free float’ and ‘locking’ lever options or a synchronised movement (the seat and backrest move together at a 2:1 ratio).

Using these will encourage the backrest to fully support your back and maintain correct positioning. It will also remove some weight from your upper body and reduce the pressure on your spinal disks and muscles. 

Swivel

The swivel enables movement, making it easier to reach different points of your desk without having to strain.

Armrests

A good adjustable office chair will have armrests that move in height (as a minimum). They help to reduce tension in the upper body, shoulders and neck, allowing the shoulders to relax, which relieves strain and tension.

Headrest

Headrests support the back of the head and the upper neck, reducing tension in the muscles of the shoulders, neck and upper torso.

Upholstery 

The upholstery or padding should be comfortable, flame-resistant (FR) treated, hard-wearing and stain-resistant. The material you use for your upholstery will be influenced by your budget as a large number of options are available.

Castors (Wheels)

Choose wheels that match your flooring type and address specific mobility needs. Opt for braking loaded or unloaded castors if you struggle with chair mobility, ensuring seamless movement in and out of your workspace.

Fine-Tuning Options

If you have specific pain, then further fine-tuning the ergonomics of a chair can achieve the perfect ‘fit’ of the chair for you. Some of these options include:

1. Inflatable Thoracic Support

An inflatable cushion in the upper centre of the backrest helps to stop slouching and increases the contact area with the backrest, between the shoulder blades. It also helps to reduce pain and discomfort in the shoulders and neck.

2. Airflow Seat

A ‘reactive seat’ is produced by the dual air chambers cell in the seat cushion. This provides cushioning to your ‘sit bones,’ which increases core strength and reduces sciatic pain.

3. Coccyx Cut-Out

This soft pocket at the centre back of the seat cushion is a discrete solution to coccyx (bottom) pain as it relieves pressure on the tailbone.

Additional Considerations (Such as Time)

On average, adults spend nine hours sitting each day. When choosing your ergonomic office chair, you should also consider how long you will be sitting in it every day, as the longer you are planning on using the chair, the more adjustable options you’ll want to consider.

How to Sit Correctly on an Ergonomic Chair

To truly feel the benefits of the ergonomics of a chair, you must sit correctly. This is how you should properly sit on an ergonomic office chair:

1. Sit at an arm’s length distance from your computer screen, ensuring your arms are parallel to the floor.
2. Ideally, position the top of your monitor at eye level for optimal viewing.
3. Sit upright and avoid slouching. Keep your shoulders back and chest open.
4. Your shoulders and elbows need to be relaxed and ideally bent at 90 degrees.  
5. Position your bottom to the back of the seat so the backrest supports your back and legs.
6. Keep both feet flat on the floor while seated, avoiding crossing your legs to maintain proper blood circulation.

How Can Incorrectly Sitting Impact Our Health?

Those who work in offices know all too well that sitting for prolonged periods can cause serious long-term health implications that you may already be feeling the effects of.

Sitting causes many stresses in our bodies, particularly in the spine. This fact has recently become more recognised by health professionals, with Public Health England and The Office for National Statistics reporting that “Musculoskeletal (MSK) conditions are the biggest cause of working days lost in the UK aside from coughs and colds.”

In 2020, MSK concerns stood as the second most prevalent reason for sickness-related absences. These issues led to a loss of 20.8 million workdays, amounting to 17.5% of total absenteeism, trailing behind only minor illnesses, such as coughs and colds.

Experience the Benefits of Ergonomic Chairs with Us

Taking into account the ergonomics of a chair and how beneficial it could be to your health is vital. Discover the science of ergonomic design with Ergonomic Chairs Direct. Experience comfort, support and transform your workspace into a comfortable and stylish haven.

Explore our range for next-day dispatch and enjoy the expertise of DSE-qualified staff and consultant physiotherapists. Use our custom chair builder to find the perfect seat for you or contact us for more information.