One in three Australians spend three quarters of their time at work sitting. (Australian Bureau of Statistics Heath Study: Physical Activity 2011-2012). This equals about 22-23 hours a week sitting at work. These statistics don’t count the time we also spend sitting on transport to work, sitting at home after work and on weekends.
Since we are sitting so much, how do you sit at a desk so that your body is in the most efficient and comfortable position? In the next two Newsletters we are going to take a look at the best way to sit at work, how your desk should be set up, tips to help your back survive all this sitting and why sitting is not ideal for your body.
1. Level foundation to begin with.
Our body has 23 discs that sit between our 24 vertebra. They act like shock absorbers that take the load of our body.
When you sit, this load is being placed on your discs of your lower back. This graph shows how different postures load the L3 and L4 discs, which is near the base of your spine.
The numbers indicate the force percentage on the L3 and L4 disc. When we sit in a slouched position, this load is 275%. If you then sit slouched like this the whole day, you can imagine what sort of damage is being done to the disc over time.
Your pelvis functions in the body as a foundation, much like the foundation of a house, with the spine sitting on top of it. If our pelvis is not on a level plane, this affects how the spine takes the force or load we are putting on our body while we sit.
So the first and most important step you need to take to ensure your body is able to cope with the force of sitting is to ensure your pelvis is neutral.
Any of the practitioners at Spinal Symmetry can quickly assess whether your pelvis is neutral so that your body can cope with this load. If you then continue to use the Dynamic Therapy to maintain this correction, you will be able to cope better with the stress of sitting.
2. Correct chair
We spend so long at work sitting in the same chair it is vitally important we have the correct chair for our bodies and it is giving the correct support specific to your body. There are many different types of chairs out there. To get the correct chair for your body it is best to talk to your practitioner specifically about your body type and the chair needed for you. However here are some important aspects that your chair should have to give you the correct support.
The seat should be easily adjustable so that you are able to have your feet flat on the floor, with thighs horizontal and arms even with the height of the desk. A common issue we see with chairs is that the seat cannot adjust so that it can easily slide under the desk. This means you are not able to get close enough to the desk and are forced to lean forward loading your lumbar spine too much.
The seat needs to have enough width and depth to support your pelvis. The depth needs to be so that you can sit with your back against the backrest while leaving approximately 5 to 10 centimeters between the back of the knees and the seat of the chair. There should also be an easily adjustable forward or backward tilt. The biggest issue we find with width and depth of chairs is people sitting in too big of chairs and again have to lean forward to reach their desk or they sit in the edge of the chair not getting the support from the lumbar support.
The lumbar support of a chair should be easily adjustable in both height and depth so it can mold to your lumbar curve. Our lumbar spine is curved in an inward way called the lumbar lordosis. It is important to maintain this while you sit so the lumbar discs and supporting structures are able to cope with the force on the body while sitting.
The backrest should be 30 to 50 centimeters wide. If the backrest is separate from the seat, it should be adjustable in height and angle. This is important because it should be able to mold to your specific curve of your back. The angle of the backrest should also be able to lock and stay in the specific position so it doesn’t move backwards when weight is placed on it, if it does move it won’t give your back the support it needs to maintain the correct curves.
The armrests should be adjustable so they can be position specific to your body. They should allow the arms to rest comfortably and the shoulders relaxed. Having too high armrests causes tension in the shoulders and too low forces you to lean forward into a slouched position.
The chair should be able to swivel so you are able to use any part of your desk without twisting your body. Any twist in your low back while sitting further loads your lumbar spine and increases the pressure placed on the area. At no point should your body be twisted to any side.
3. Posture while sitting
To be able to sit in an efficient and comfortable position you need to maintain a neutral body posture. To achieve this you need to sit with the following:
Hands, wrists and forearms are straight, in-line and parallel to the floor. A good way to remember it is having Dinosaur T Rex arms with your elbows close to your body bent between 90 to 120 degrees; preferably resting on the arm rests.
Head is in-line with your torso with your ears on top of your shoulders.
Shoulders are relaxed and upper arms hanging normally at your side.
Feet are fully supported by the floor or footrest with both feet even on the surface.
Back is against the chair using the lumbar support
Thighs and hips are supported by the seat and parallel to the floor.
Knees are the same height as the hips with feet slightly forward of the knees.
In Part 2 we will continue to look at ways to help your body while sitting. We will look at your computer screen, mouse and keyboard, what happens when you need to change between screens and the best ways to have breaks and keep moving.