Poor posture is learnt early in childhood and made worse by badly designed school furniture. You learn early on to slouch in your seat to try to overcome the torture of a horizontal seat and a vertical backrest (often set too far back to be of any use or value). Even if you were lucky enough to get a chair or seat close to your size, very often the desk was the wrong height and in almost every case there was no lumbar support whatsoever. Thus the stage was set for you to learn how “not to sit.” If you learnt nothing else at school, your body learnt this lesson very well!
The posture you are forced to adopt when sitting in a conventional office chair (whether it’s labelled ‘ergonomic’ or otherwise) is one where your body is constrained by your trunk and thighs having to form a right angle (90°). What happens when you sit in this position is that your hips bend to 60°, your pelvis moves backward and your lumbar spine flattens out to take up the remaining 30° thus placing an unnatural strain on your muscles, joints and ligaments. This strain is felt most acutely at the end of a long working day as back pain of varying degree and intensity.
The ideal posture when sitting is one which helps to maintain the natural lumbar curve or lordosis of the lower back - this is when our discs, joints and ligaments are under the least amount of stress. However, it is just not possible to achieve this ideal posture using a conventional chair where the seat and backrest are at right angles. When we take up this position there is excessive pressure placed on the lumbar vertebrae of the low back. This pressure will eventually cause lower and sometimes upper back pain.
Some things you can try to minimise this discomfort.
While watching TV
When your children are sitting in front of the TV, encourage them to sit on the floor rather than in the standard lounge chairs; or buy some inexpensive ‘bean bags’ as these place less strain on young spines.
1. To figure out the correct amount of lordosis (lumbar curve) for sitting with minimum strain, Physiotherapist Robin McKenzie has suggested the following:-(*1)
Sit forward on your chair so the backrest doesn’t interfere while you learn this.
Allow your body to slouch to its maximum and hold that position for a few seconds.
Then reverse this position so that you are sitting totally erect ( the limit of your lordosis ) - again hold for a few seconds.
Repeat several times so that you can feel and understand the difference between these two extremes.
Take up the totally erect position and then allow your body to relax by 10%.
This is about the best sitting position for the lumbar spine (if you can remember to maintain it). Do NOT try to keep up the fully erect position as this will cause pain.
2. Using a wedge-shaped support to gain some forward-sloping effect can offer a stop-gap solution to keeping your back in a more correct posture and relieve some of the pressure or you might try to find some way of tilting the seat pan of your chair forward.
3. Some temporary relief may also be achieved by carrying out regular exercise.
4. In a similar fashion, if you are experiencing pressure on your hamstrings, you may find that sitting with your legs tucked back underneath the chair can often help to bring you some relief.
At the Keyboard.
You can maintain good posture at your keyboard when:-
Your lumbar curve is at 10% less than maximum.
Your trunk and hips are at an angle of about 110° - i.e. forward-sloping.
Shoulders are relaxed - not hunched.
Your head and neck are in a ‘neutral’ position.
Elbows at about 90° and level with the middle of the keyboard.
Your upper arms are vertical by the sides - not out or forward.
Wrists are in mid position with your hands in line with your forearms.
At Anytime MOVE! MOVE! AND MOVE AGAIN
In addition to excessive pressure on the spine, lack of movement can have quite serious effects on the discs of our spinal vertebrae. So walk instead of drive, take a walk around the block with your kids! Take up Tai Chi or Yoga, learn Aerobics. Just get moving!
You might like to check out the exercises page on our website