When sitting, weight from upper part of the body, presses downward through the spine, through the pelvis and onto a chair. The point of contact made by the pelvis on a seat (ischial tuberosity) is usually in front of the downward pressure from the spine. These divergent lines of force cause a backward rotation of the pelvis. For most people, this combines to produce a “C” shaped curve in the lower back. In this position, the backward rotation of the pelvis is linked with flexion of the lower lumbar spine. It becomes so easy to keep the back flexed in sitting that this posture starts to feel normal. This position has become universally adopted as the habitual sitting posture. Most people keep the lower back near the limit of forward flexion for extended periods of time when sitting. The flexed position causes higher spinal load, measurable with higher internal disc pressures. Lack of movement in this position reduces circulation and results in spinal stagnation.
Click here for an animated version.
- Test your position after you have been sitting for a while.
- Feel how far you are able to roll the pelvis forwards and backward.
- Are the movements equal in both directions?
- How does this movement compare with standing?
- Place a mark on a Movement Circle to indicate your position when sitting.
Position Awareness worksheet
Learning to Sit
- Sit upright on something very soft (a wobble cushion, hot water bottle or soft cushion) and gently lengthen the spine with minimal muscle effort. It should feel like there is a relaxed lengthening of the spine.
- Allow the pelvis to roll comfortably forward and back to establish how far it can move without discomfort.
- Be aware how far the movements extend into the 4 zones in each direction.
- Try and estimate the mid position, close to the centre of your zone 1.
- You can check your movement by either looking into a mirror placed to one side, asking someone to take a photo of you, placing your hands over each side of the pelvis, or by placing one hand with fingers spread wide over the abdomen and the other over the back. Now stand up and check the movement of your pelvis forward and backward, then find the mid position again. Now compare the mid position in standing with your estimate of the mid position in sitting. Repeat the comparison from standing to sitting until you are able to match the same mid position.
- Use this position of the pelvis and curve in the low back as your new reference position for sitting. The position should feel relaxed, balanced, use minimal muscle effort and be close to zone 1.
- Don’t need to stay fixed in this position, you should feel free and comfortable to move near your new reference position.
Make it Automatic
Use the new reference position as your starting position. You should be able to move the pelvis a small way in all directions without pain or discomfort. The muscle in the back should be gently supporting the weight of your body with minimal effort, similar to when you are standing. It may help to imagine a small helium balloon tied to the top of your head or a tiny golden thread gently lengthening the spine. The result should be a relaxed lengthening of the spine, with the spinal curve controlled just by tilting the pelvis. Allow yourself unrestricted breathing and almost no effort from the supporting muscles. To establish this new reference position as a habitual posture requires small, slow, pain-free movements to be repeated near the new reference position. These small, slow movements help to reorganise the brain’s ability to recognise this position as being familiar (and eventually normal). You will also develop an awareness of when your back is not in a mid-position.
HOW? Initially, sit on a chair using a soft cushion or something similar to allow the pelvis to move easily.
- find your new reference position
- gently lengthen the spine
- slowly move the pelvis using small movement that gently challenge your perception
- check your reference position
- gradually increase the complexity of your movements
- gradually reduce the size and speed of your movements
- try the movements when sitting on different surfaces
- relaxed breathing should be possible during the exercise
Are you able to match your movement to these animations?
Stay safe, comfortable and controlled throughout the exercise
Rotation of the Pelvis should lead the movement
Movement in 4 Directions.
You may initially find maintaining this position difficult until your body adapts. Placing a support at the lowest part of the back / upper pelvis may assist you in maintaining the new reference position. The support allows you to position your back away from the end range loading in Zone 4 where spinal loading is high. When using a passive support, there is no active retraining of sitting perception and sitting habits are unlikely to change as a result.
Our body is designed for movement and exercise. Most people will not be able to remain perfectly still for long periods of time. Changing position and making small movements near the new reference position is sensible if you need to stay sitting for long periods of time. It is sensible to take short frequent breaks from sitting and move around whenever possible.
Hip pain and stiffness may impair your ability to achieve and ideal position for your pelvis and back. In this situation, position the knees lower than the hips by either raising the chair or sitting on a wedged cushion. Sitting advice by A.C.Mandal can also be helpful.
Trying to “sit up straight” without changing the position of the pelvis will only over-tighten the back muscles leading to early fatigue and a return to the habitual sitting position. Occasionally, some people have over activity of the back muscles (lumbar extensors) resulting in a rigid, upright posture (extensor over activity pattern). Any functional change to your sitting position will involve minimal muscle effort and an awareness of how to relax in a new position. Initially, when learning a new activity, far more effort is used until the skill is acquired. Efficiency comes with awareness and practice. The more you practice to change in your sitting habits, the easier and more automatic your new sitting position becomes.