By slumped sitting I mean the most natural form of sitting practised by all of those who continue to sit on the ground without the use of chairs. The main part of the spine is allowed to slump as far as it will flex without any attempt to sit upright as we are told to do.
Slumped sitting is the most important stretching exercise for the spine. It takes no time to practise each day because we can sit slumped on the ground when we are watching television or chatting to friends and family. I say that it is the only stretching exercise that the spine needs. It is much better than most spine stretches which almost invariably stretch the lumbo-sacral Junction without having much effect elsewhere.
Having been told early in life that we must always sit up straight most of us actually have to learn slumped sitting. This (see picture) is a very comfortable form of slumped sitting with the knees hooked into the elbows and one hand holding the other wrist. Any picture of a group naturally living people shows one or two of them sitting in exactly this position. The support by the arms is not however important. The important thing is the slumped shape of the spine with the body approximately vertical. Wherever the legs are it is bound to be a good stretch for some muscle in the hip joint.
When sitting like this it should be obvious that at some point in the upper thoracic spine, the spine ceases to be slumped or relaxed otherwise the head would be facing downward! From this point upwards the spine and the neck must be active for the face to point horizontally. I find it best not to think about this but simply look at the television or the people you are with, without conscious effort. The body will sort this out because it is a natural way of sitting.
The mechanics of squatting are very similar, for most of the body, to slumped sitting. (The differences will be covered elsewhere under "squatting") We have undoubtedly been practising this form of sitting for 5 million years and, on the principle of Ndjmayl defined earlier, the body will have evolved to compensate for all forces and effects of slumped sitting. If we do not sit in this way as a regular habit then many problems will result.
The following, quite long, description of the advantages of slumped sitting and the consequences of never sitting slumped is probably only a part of the story:
Slumped sitting will stretch all the muscles and ligaments of the spine in a totally natural and even way. If a 10 second stretch has an effect on a muscle or ligament of a joint then a stretch lasting several hours will be of major importance. Not only will slumped sitting stretch the muscles and ligaments, it will straighten the spine and even out the flexion or mobility at different joints. This is because many of the ligaments and muscles the spine are at an angle to the axis of the spine and will therefore become much more effective as the flexion at that joint increases. This applies to the interspinous ligament, to the lumbo dorsal fascia, to the rotatores muscles, to the very important parts of the lumbo dorsal fascia which connect the L4 and L5 spinous processes to the iliac crest and to many other muscles. In addition the supraspinous ligament will tend to pull all the vertebrae into line when tensioned.
Thus slumped sitting will adjust all components of the back towards their natural state.
In slumped sitting the spine will flex and the thorax will fold downwards until the abdomen can distort and compress no further. Thus in slumped sitting most of the weight of the thorax and upper body will be carried by the abdomen and the compressive force in the spine will be greatly reduced. (Indeed there may be no compressive force in the spine)
I have shown elsewhere, particularly in the paper "The Obstetric Reason for Lordosis..........", that the abdomen forms an important and essential part of the structure of the body. The researchers on core stability have shown how all the muscles of the abdominal 'pressure vessel' work automatically in conjunction with the spinal muscles. It should now be clear that the abdomen also forms an essential part of the body structure in sitting and in squatting. That is, in the most natural forms of sitting there is very little stress on the spine. This is the opposite of most forms of civilised sitting where the maximum stress is applied at the base of the spine, the most vulnerable part.
Just as the muscles and ligaments of the spine will stretch and be adjusted, or tuned, by sitting, so also will all the ligaments and muscles of the abdominal pressure vessel. This includes the transversus abdominis, the diaphragm and the pelvic floor muscles. Of particular interest is the transverseus abdominis because it provides the horizontal force around the abdominal wall, which produces a tension in the lumbo-dorsal fascia. This force in turn produces a small extension force at spinal joints, which will be significantly greater at any joint with larger mobility because the separation of the spinous processes will be greater.
Thus, without going into excessive detail, slumped sitting will slowly and gently stretch not only the muscles and ligaments of the spine but also all of the muscles and ligaments of the abdomen, the diaphragm and the pelvic floor and thereby adjust the lengths of all of these components in a totally natural way so that they work, as evolved, with one another in all other activities such as running jumping and lifting. Slumped sitting provides the "reset" for the body system.
Research notes: Core Stability. Book ". Superb detailed work showing how the abdominal pressure vessel works.
Those who know the literature will observe that my suggestion on the reduced compression in the spine is the opposite of Nachemson's experimental work on intra--discal Pressure. If the subject only sits in the normal civilised ways then the spinal muscles will tighten before any others giving those experimental results.
The Diaphragm and Breathing.
In slumped sitting it is the diaphragm, which is the top of the abdominal pressure vessel. The abdomen is not compressible so the diaphragm will remain in the same place when breathing. The effect of contraction of the muscles of the diaphragm will be to raise the thorax (and therefore also the arms, head etc). You can easily check that this is what happens if you are in the habit of slumped sitting.
Thus continuously, when slumped sitting, there will be a tension in the muscles and ligaments of the diaphragm to support the upper part of the body. This tension will stretch these components and cause the diaphragm to distort into a more domed shape compressing the lungs. This effect has applied for the last 5 million years, while we have had this body and these ground sitting habits, so the strength of the diaphragm will have adjusted correspondingly. If we never sit in this way then there is no time when this continuous force will be applied to the diaphragm. The diaphragm will not therefore receive the stretching effect that it was designed for and will sit lower in the body and be unable to provide as complete expiration as the lungs are designed for. This is another example of the Ndjmayl principle: that we must practise the same habits we have done during the evolution of our body or disadvantages will result. Research note; I know of no experimental work to suggest that this does happen but from this logic, it almost certainly does. Thus far from damaging our breathing, as often suggested, slumped sitting is necessary to ensure correct function of the breathing system.
At many points in this web site I have emphasised that the centre of the low back pain problem is the "shape warning pain". This is triggered when either L4-5 or L5-S flexes too far. Does this mean then that we should never bend the back at all? No obviously it doesn't. But what are the characteristics of the shape warning pain? The nerves in the posterior annulus of the disk probably behave exactly as common sense would suggest that they would behave. If the nucleus of the disk has never got near these nerves then they will be primed to cause the maximum pain when this does occur. If we are in the normal habit of sitting slumped and squatting on a daily basis, then the nerves will be accustomed to this level of flexion and will not react to the flexion, and approach by the nucleus, when it occurs in other activities like lifting and bending.
It is therefore essential that we do sit slumped for a period every day otherwise the shape warning pain will be too sensitive and cause problems and pain when it isn't meant to. Slumped sitting and squatting are the normal way of adjusting the setting, which defines when the shape warning pain should be triggered. This is how evolution has designed the system! (This is in addition, of course, to the arguments above, about the muscles needing to be stretched.)
Note; This does not mean that slumped sitting should be practised when you are suffering from a back problem. This is an information website rather than a ‘how to treat yourself’ website. I usually warn patients that they should not sit slumped if, on trying to get up afterwards, they get twinges on straightening up. See Low back Pain
As an aside to this particular argument, this may be the place to raise another question and a sort of answer. One could extrapolate from the argument in the above two paragraphs to say that it really doesn't matter what shape the discs are, so long as they are fully flexed enough of the time to desensitise the nerves that trigger the shape warning pain. In other words there isn't a shape warning pain at all and all you need to do is lots of flexion. Up to a certain age, maybe 20 or so, this seems to work for most people. It is certainly my belief that most children and young adults living our civilised lifestyle to not comply with my limitation on the flexion of the lowest two spinal joints. However, although the back problems only become really important for adults, they are not unknown in children and teenagers and I believe that we will only make any significant improvement in the level of back problems when we recognise the existence of the shape warning pain as I have defined it.
Rounded Back, Round Shoulders, Dowagers Hump, Baker's Hump etc
(or whatever you want to call it)
It seems obvious that slumped sitting is going to have the effect of producing a rounded back shape. This is presumably why we are told from childhood always to sit up straight and not slump.
In fact the exact opposite is the case. Slumped sitting (and even more, squatting) is the best protection against developing a rounded (or excessively kyphotic) shape in the upper back. It is these habits that probably maintain such a beautifully straight upper back in those who live a more natural lifestyle than ourselves.
This explanation will require some drawings, which I haven't got the time for at the moment. There are also several more sections to be added such as hip joint mobility, shoulder joint looseness and sacro-iliac joint mobility. These will be done soon!!! First of March 2005.!!!