Why do I need a chair with adjustable lumbar support?

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One of the most important features to look for when selecting an office chair, is lower back, or lumbar support. Ergonomic and orthopaedic office chairs in South Africa are fitted with various types of back support that range from multi-adjustable backrests, to portable lumbar cushions that are attached to the chair by means of a strap.

Office chairs with good lumbar support will keep your spine aligned in it’s natural elongated ‘S’ shape.

lower back support for office chairs
Maintaining the natural elongated ‘S’ shape of the spine

Made up of 34 bones, the spinal column holds the body upright, allows it to bend and twist, and provides a conduit for major nerves running from the brain to every other part of the body. It provides the structural and nervous system support for your body.

lordosis and kyphosis curvature in back
Lordosis and Kyphosis curvature in the spine
lumbar spine
Lumbar vertebrae in the lower spine, L1 to L5

The five vertebrae (L1 to L5) in the spine between the diaphragm and sacrum are known as the lumbar spine. This section of your spine curves slightly inward, called lordosis, before extending down to your tailbone.

An office chair with good lumbar support will maintain the lordosis curve while you are sitting.

The primary goal of the lumbar support in your office chair is to maintain the lordosis (natural inward curve) of your lumbar spine.

Chairs that don’t do this are not only uncomfortable, but they can result in chronic back-related ailments.

lumbar back support for office chair
Orthopaedic office chairs have a highly adjustable lumbar support to promote good posture and minimise the strain on your lower back.

1. What happens when you sit?

When you sit with our thighs at a 900 angle to our back, two major skeletal movements take place. Firstly, the long thigh bones (femurs) rotate in their pelvic sockets through approximately 600. Thereafter, the ligaments attaching the femurs to the pelvis, pull on the rear of the pelvis. This rotates it backwards through the remaining 300. Due to the rotation of the pelvis, the natural lordosis curve in the lower back changes to a kyphosis curve to create a ‘C’ shaped spine as shown below.

what happens when you sit and kyphosis in lumbar spine
When you sit the kyphosis curve squeezes the front edges of the vertebrae together to create a ‘C’ shape (right). This increases the pressure on the front portions of the intervertebral discs.

Most of the change to a kyphosis curve occurs in the first three or four vertebrae above the pelvis. During this process, the front edges of the vertebrae squeeze closer together while the back edges spread further apart. This increases the pressure on the front portions of the intervertebral discs. For more information, see What actually happens when you sit?

To prevent poor sitting habits, select an ergonomic or orthopaedic chair with good lumbar support.

Without proper lumbar support, prolonged sitting with a “C” shaped spinal curve can lead to:

  • Backache.
  • Neck pain and tension headaches.
  • Sciatic nerve pain or sciatica.
  • Impaired breathing due to the compression of your lungs which restricts the blood flow to your vital organs, specifically your brain. This results in fatigue and poor concentration.

2. Why the back support on an office chair should be adjustable

Because our bodies are so varied, chairs with a fixed or pre-defined lumbar support, are not suitable for everyone. An adjustable lumbar support allows you to position the lumbar cushion to best fit and support the curvature of your spine.

In South Africa where we commonly have “hot desking” and office chairs are used by more than one person, an adjustable lumbar support is all the more essential. Remember that when it comes to office chairs, “there is no, and never will be, a one-size-fits-all”.

3. Who needs an adjustable lumbar back support on their office chair?

The simple answer…..EVERYONE!

An adjustable lumbar back support is recommended if you are sitting on your office chair for long periods of time, and/or you have persistent muscular back pain or musculoskeletal disorders.

4. Different lumbar support options and how they work

Lumbar back support for office chairs in South Africa is available in various forms that range from the most basic to more advanced ergonomic options. Office chairs with a high ergonomic rating will have backrests that include multiple types of lumbar support adjustment. Let’s have a look at a few variations.

a. Height adjustable

This option allows you to adjust the lumbar support vertically to suit your lumbar curve.

vertical lumbar support adjustment on Alya office chair
Vertical lumbar adjustment (Alya)

In order to get optimum results, sit as far back into your seat as possible with your back fully supported by the backrest.

Now adjust the lumbar support so that it rests in the small of your back to maintain the natural curve of your spine.

Ensure that the lumbar is not too high or too low as this may lead to slouching and discomfort.

b. Depth adjustable

This option allows you to change the horizontal depth of the lumbar support. 

When you adjust the depth of the lumbar support cushion on an office chair, ensure that you keep the spine in a natural position. Don’t over or under accentuate the inward curvature of your spine.

Over accentuation will result in unnecessary strain as your spine is forced into an extreme lordosis, while under accentuation will not provide the necessary support and comfort.

Note: Females have a greater inward curvature (lordosis) than males, and would benefit from a more pronounced lumbar support.

depth adjustable back support on Alya office chair
Depth adjustable lumbar support (Alya)

c. Height adjustable with fixed lumbar support

Here the entire chair backrest can be adjusted vertically so you can align it with your lumbar curvature.  

The height of the backrest can adjusted vertically to provide the best lumbar support. Normally the adjustment is accomplished by means of:

  • A ratchet mechanism that has a number of setting positions, or,
  • a handwheel that allows variable adjustment.

d. Portable lumbar back support cushion for office chairs

These cushions are made from moulded foam and then upholstered with either a plain or breathable mesh fabric.

Portable cushions come in various shapes and sizes and can easily be attached to your office chair or car seat by means of adjustable straps.

Their application is ideal for any seat with insufficient lumbar support.

Portable lumbar support cushion

5. How to adjust the lumbar back support on an office chair

Lumbar support should always be adjusted in conjunction with the correct chair setup.

  • Set the chair to the correct height relative to your height and that of the desk.
  • Sit as far back into the seat as possible and lean into the backrest of your chair. Your entire spine should be in contact with the backrest.
  • Raise or lower the height of the lumbar support to fit your lumbar curve. Incorrect positioning will result in discomfort and slouching.
  • Finally, adjust the depth of the lumbar support. Be careful not to adjust the lumbar support too far inward as it may result in pain and discomfort. Too little pressure provides inadequate support.

Conclusion

Working in an office requires you to spend a significant amount of time sitting on your office chair.  An office chair that supports the lower back and promotes good posture is essential to avoid developing or aggravating back problems. The Latest Trends in selecting a Comfortable Office Chair.

A chair with adjustable lumbar support should not be an option or a consideration. It should be a “must have”.


Author: Ronel Hendry
Office Ergonomics Risk Facilitator at Karo Manufacturing (Pty) Ltd
21 June 2021

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