You have seen kneeling chairs online, as well as in shops and offices in South Africa. Your friends may have purchased one. You have heard that a posture chair is good for lower back pain. You are thinking about buying one and you ask yourself….”what are the pros and cons of a kneeling office chair, and is it suitable for me?”
The answer to this question is a simple ‘yes’, provided that you understand the ergonomic principle of a kneeling chair, and you use it correctly.
To help you decide if a Kneeling Chair is right for you, in this article we will discuss:
1. What happens to the body when we sit?
We first need to look what happens to our body when we sit and our thighs are at a 90 degree angle to our back:
As we begin to sit, the long thigh bones (femurs) rotate in their pelvic sockets through approximately 600. The physical limitations of our body prevents the femurs from rotating the full 900 required to sit, so the remaining 300 must come from “somewhere”.
As we sit down completely, the ligaments attaching the femurs to the pelvis pull on the back of the pelvis, rotating it backwards through the remaining 300 and this causes a flattening of the lumbar curve.
Due to the rotation of the pelvis, the natural inward curve in the lower back changes to a outward curve. Most of the change to an outward curve occurs in the first three or four lumbar vertebrae. 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.
2. Principle of a kneeling chair
In South Africa, the name “kneeling chair” can be a little misleading as it leads you to believe that your knees are taking the bulk of your weight and replacing the function of your buttocks. This actually isn’t the case. Your buttocks will still carry about 80% of your weight, and the knee pad is only there to act as a support so you do not slide off the inclined seat.
The underlying principle of a posture chair is to maintain an ‘open’ pelvis while you are sitting. This reduces the strain in your lower back that normally occurs when you sit on a conventional chair. An ‘open’ pelvis is when the angle between your spine and thighs is at least 1100.
By opening the pelvis and lowering the knees in relation to the hips to create a 1100 back-thigh angle, the disc pressure in the lumbar region of the spine is reduced by up to 65% when compared to sitting in the traditional 900 back-thigh angle position.
3. Benefits of a Kneeling office chair – the PROS
There are numerous pros and cons of kneeling chairs. Let’s first look at the pros.
When Peter Opsvik designed the original Balans ergonomic kneeling chair in 1979, movement and variation were very much what he had in mind. Opsvik recognised that sitting in the same static position for a long period of time is bad for your body. With a posture chair, there is no one particular correct position that you are required to sit. Rather you should change your position on the kneeler frequently as this will result in improved blood circulation and also relieve some of the pressure points on the knees and shins, thereby reducing any initial discomfort.
4. Limitations of a Kneeling office chair – the CONS
Although there numerous pros, there are also cons associated with some kneeling chairs available in South Africa. Be aware of the cons before you decide to purchase one.
5. What is the best way to sit on a kneeling chair?
Some people initially find it difficult, and even uncomfortable, to sit on a kneeling chair. It is important to understand why this might be and how to resolve it. It’s likely that as a new kneeling chair user, you will have previously sat on a traditional office chair, so it’s only natural that it will feel awkward at first.
You need to bear in mind that sitting on an office chair and sitting on an ergonomic kneeling chair are two entirely different experiences. Your body will need time to adapt to an open posture seating position. Just like when you change cars or buy a new pair of shoes, you need to allow some time for things to settle down so your body adjusts to a new way of sitting.
Muscles and bones that are familiar with a particular seating position will need to become accustomed to a kneeling chair. Your body needs to rebuild the core muscles in your lower back as they may have become weak from sitting on a conventional chair.
Your body needs to adapt to sitting on a kneeling chair
a. Vary your position on the kneeling chair
You should start by sitting on the seat of the kneeling chair before moving into the kneeling position. The bulk of your weight needs to be on your buttocks. Returning to Peter Opsvik’s concept of variation and movement, it is important to vary your seating position on your kneeling chair frequently during the day.
b. Ensure the work surface height is correct
The height of your chair with respect to your working surface is the foundation of your posture.
As with any chair, if your working surface is too low, you will automatically hunch forward and your spine will be out of its natural alignment. This must be avoided at all costs. With a kneeling chair, hunching forward will further increase the pressure on your knees and shins, thereby causing discomfort.
If your working surface is too high, you will have to raise your shoulders to be able to work. This may result in your neck and shoulder muscles going into spasm.
Your work surface is at the correct height when your elbow is at 900 and your forearm is in line with the top of your working surface. Your palms should be resting flat on the working surface.
c. Adjust the height of the kneeler
To achieve the correct height relationship between you and the working surface, you will first need to adjust the seat height of the kneeler. It is important to select a kneeling chair that has independent seat and kneepad adjustments – many don’t! Once the seat height is correct, adjust the kneepad to a position that you find most comfortable.
In some situations, you may find that the height of the kneeler cannot be adjusted to match the work surface, and typically the work surface will be too low. Under these circumstances, you would need to look at changing the height of the work surface or desk.
There are some easy ways of doing this. For example, by using books to increase the height of the work surface. See The perfect office setup. A more elegant solution would be a height adjustable desk. These can easily be set to the correct height irrespective of the type of chair you are sitting on. Height adjustable desks have many pros and few cons, and can be used in conjunction with a kneeling or conventional office chair. Some companies, like Uber South Africa, truly understand the ergonomic advantages of such desks and have furnished their entire offices with adjustable desking. Best practices for ergonomics in the workplace.
There are many variants of kneeling chairs available in South Africa and there are pros and cons of each. Do your homework and test various models. Ensure that you sit correctly on the chair and you have adjusted the seat height to suit your work surface.
It is a good idea to keep your existing office chair so that you can alternate between the two until you get used to your new kneeling chair. In fact, some users actually prefer to use both chairs and this is a highly recommended solution.
Revised: 24 March 2021
Author: Achim Roetger
Director at Karo Manufacturing (Pty) Ltd