In ‘ideal’ sitting, the lumbo-pelvic spine is in the ‘neutral’ lordotic curve – the entire spine is supported upright against gravity in its natural curves.

Unfortunately this is not usual. Sitting with ‘poise’ is a fast dying habit – and ability! What’s usual is habitual slump sitting¹ – an epidemic that appears to be a potent contributor feeding into the development and perpetuation of many spinal pain and related problems.

Done often enough and long enough it leads to an inability to ‘naturally sit up straight’. This is apparent in literally every patient I see – and if you look, I can confidently predict, will also be evident in your patients.

We need to address this postural habit and be clear on the best way of doing so.

There are various descriptions of ‘lumbar neutral’ sitting – and not a clear consensus to date of what is ‘ideal’. O’Sullivan et al² define a ‘neutral sitting posture’ as achieved by tilting the pelvis slightly anteriorly while maintaining a relaxed thoracic spine. This is clinically applicable and relates to functional control. I hope to further clinical understanding around this subject and offer some practical solutions for retraining functional movement control.

There are two things to consider when looking at someone’s ability to ‘sit up straight’:

1. The shape or line of the spine and pelvis in sitting – the ‘posture’, and more importantly
2. ‘How’ this is achieved and maintained by the neuromuscular system

Posture

 I find it practically useful to look at an assembled skeleton in sitting. I can only assume that the natural geometry of the bones is what dictates the form of the spino-pelvis as we know it. Note a clear lumbo-pelvic lordosis – and a slightly anteriorly tilted pelvis. Importantly, for the spino-pelvis to be ‘up’ and ‘neutral’ in sitting, the hips need to be able to flex well.

The base of support to the whole spinal column is the pelvis – through the ischial tuberosities – better known as the ‘sit bones’. But, most people don’t sit on these! – but roll off the back of them. The spine then has to follow and is loaded into end range flexion – particularly the low lumbar segments. Research shows that when lumbar discs and facets are held at end range flexion the neurophysiology³ and hence muscular control is adversely affected.

It’s unusual to see an excess lumbo-pelvic lordosis! What is often construed as an ‘excessive lordosis’ is actually higher up in the lumbar spine through overactivity of the thoraco-lumbar erector spinae. This is not ‘natural’ – or desirable function.

So ‘how’ do you actually control the spine?

1. ‘Healthy sitting patterns’ rely on Fundamental Patterns of pelvic and axial control While the ‘shape’ of someone’s spine is somewhat informative – more significant is ‘how’ that person supports his spine when antigravity. A person’s ‘posture’ tells you a lot about the status of their neuromuscular system. While ‘slump sitting’ is commonly habitual – when cued to ‘sit up’, it’s relatively easy to appear to ‘look good’ – but not ‘feel good’ as the person is invariably utilising inappropriate excess superficial neuromuscular activity – particularly the thoraco-lumbar extensors – which is both palpable and observable.

This compensatory regional ‘lock in’ strategy for antigravity control (what I call a ‘Central Posterior Cinch’ pattern) is very costly to the healthy physiological functioning of the spine – segments are compressed and bothered and can’t move freely. Breathing freely with the diaphragm and ‘core control’ is compromised. Hence why Peter O’Sullivan would qualify a ‘neutral position’ as one ‘with a relaxed thoracic spine’.

Yet, it’s important to appreciate that people have to adopt this strategy if their ‘inner unit’ or ‘core’ (what I call the ‘Lower Pelvic Unit) control is under-active – (and if they have regions of segmental stiffness – which is usual!).

Note that O’Sullivan also talks of a slightly anteriorly tilted pelvis.

How’ the pelvis is controlled is the crux of the matter yet this often completely missed by most clinicians and researchers. Sitting with a low lumbar or ‘short lordosis’ requires a ‘neutral pelvis’ (slight anterior rotation) and this necessitates the ability for ‘closed chain’ hip flexion to rotate the pelvis anteriorly on the femoral heads. To do this requires capacity of the ‘inner Lower Pelvic Unit’ (LPU) to both control the First Fundamental Pelvic Pattern – and also provide ‘inner’ postural support to the spine through the IAP mechanism. In healthy control, sitting with a ‘short lordosis’ posture activates key trunk muscles without significant activation of the large torque producing muscles⁴. In this position, psoas as part of the LPU is particularly involved in achieving adequate hip flexion/lumbar extension⁵. In a healthy neutral posture the breath is free and ‘deep’ – which creates a subtle postural sway as the breath comes and goes. It is not rigid holding.

If control from the LPU synergy is underactive both in controlling the pelvis and particularly in creating adequate Intra Abdominal Pressure for ‘inner’ spinal postural support and control, the person has to compensate! They do so by ‘holding themselves up’ with excess ‘global’ superficial extensor muscle activity – particularly around the thoraco-lumbar region – a bit like holding a building up via external scaffolding because it has poor foundations. Note that in the second photo in my last blog there is some apparent (yes subtle!) overactivity of the thoracolumbar extensors. The point of the photo was to demonstrate controlling the pelvis against the hamstrings. However there are many pieces to the ‘functional puzzle’ – we also need at the same time to be working on the Fundamental Pattern of ‘core control’ to help down-train this paraspinal muscle hyperactivity – which has a tendency to further increase if not watched for when working for retraining better patterns of pelvic control.

Look further at the 3rd photo – as he needs to stabilise his pelvis and spine against the required knee extension against the tight hamstrings being asked to lengthen, he further fires his thoracolumbar extensors – and upper antero-lateral abdominal wall. He does so because he has inadequate control from the deep stabilisation system of the spine. While this may appear subtle – probably you may even think inconsequential – it’s important that you can see it! This could be the difference in an elite athlete ‘making it or breaking it’!. If we are judicious we can use sitting a means to improve deep system control in many ways! – and in particular for both ‘core’ and pelvic control!

Further, without adequate support and control of the deep stabilisation system of the spine, psoas activity in particular can create a ’yanking’ stress on the spine – engendering further costly excess superficial extensor thoraco-lumbar ‘lock down’ strategies in attempting stability/control. (3rd picture alluded to above) A buoyant adaptable upright posture and the ability for postural shifts and controlled sequenced segmental movements are lost

Not one of the patients I see can ‘naturally’ control their pelvis well – and so they also can’t control ‘lumbar neutral’ well. Hence why I place great store on the ability to re-establish correct control the Fundamental Pattern of ‘Core’ Control and also the four Fundamental Pelvic Patterns. These provide ‘the inner foundations’ of control for the spinal column and pelvis – allowing an adaptable base of support for the spine which also gives it a ‘natural inner lift’ and flexible control of movement. Sitting can then become more ‘dynamic’ and allow natural spinal micro movements and weight shift. If you advise your patient ‘to sit up’ without also working to re-establish these Fundamental Patterns of Control –  you will most likely further imprint provocative compensatory patterns of control which create spinal rigidity

It’s worth mentioning that achieving an ‘easy’ lumbo-pelvic neutral in sitting is difficult for many – even in so called ‘healthy’ controls used in research! Part of the title of a paper by Claus et al⁶ asks: “Is ‘ideal’ sitting posture real”? They summarise: “Results show that although subjects imitated postures with the same curve direction at thoraco-lumbar and lumbar regions (slumped, flat or long lordosis), they “required feedback/manual facilitation to differentiate the regional curves for the short lordosis posture’.

This shows us how careful and judicious we must be in re-establishing Fundamental Patterns of Pelvic control in our patients. Therapeutic skill and experience is required⁷ If these ‘healthy subjects’ had difficulty controlling the spino-pelvic neutral – by the time they present with back pain, control difficulties are apparent in spades!

In conclusion: Control of the low lumbar lordosis is physiological and important functionally. There seems to be a myth out there that the lumbar lordosis needs to be got rid of. And here lies the root of many patient’s problems.

Clinically, over-flexing the mid/low lumbar spine and pelvis in posture and movement is almost always apparent. What happens higher up varies according to subgrouping. Some over-activate thoraco lumbar extensors more than others – which thrusts the lower pole of the thorax forward – and ‘looks like an increased lordosis’.

Yet clinically, control of the lumbo-sacral lordosis is almost universally lacking in all lumbo-pelvic and related pain disorders. This has further implications – apart from difficulty in ‘sitting properly’ – it affects actions like stretching the hamstrings which instead, likely bother the spine. Basic repetitive daily actions such as bending forward and sit to stand/ sitting down are also compromised. Research has shown that the preparatory anterior pelvic rotation and forward weight shift necessary when moving from sitting to standing – or standing to sit is significantly reduced and delayed in people with LBP compared with controls⁸.

Just about everyone I see for treatment has been on a long journey seeking help. Sadly, they have invariably been told to by their physiotherapist – or Pilates/yoga teacher or fitness trainer to ‘flatten their back’; ‘tuck their tail’; pull in their stomach; pull up their PFM; clench their glutes etc – none of which switches on the deep stabilisation system of the spine to provide healthy patterns of inner support and control for the pelvis and spine – but instead lands them with deeper problems

And then we have to look at commonly prescribed stretches – many of which further bother the spine…………..       That’s another story!

References

1. O’Sullivan K et al 2010. Neutral lumbar spine posture in pain free subjects. Man Ther 15(6):557-561

2. O’Sullivan PB et al 2002 The effect of different standing and sitting postures on trunk muscle activity in a pain free population Spine 27:1238-44

3, Solomonow M 2012. Acute repetitive lumbar syndrome: a multi-component insight into the disorder. Journal of bodywork and movement therapies 04/2012; 16(2):134-47.

4. O’Sullivan PB et al 2006. Effect of different upright sitting postures on spino-pelvic curvature and trunk muscle activation in a pain free population Spine 31(19):E707-12

5. Park RJ et al 2012. Changes in Regional Activity of the Psoas Major and Quadratus Lumborum with Voluntary Trunk and Hip Tasks and Different Spinal Curvatures in Sitting J Orthop Sports Phys Ther. Epub 5 Sept doi:10.2519/jospt2013.4292

6.Claus et al 2009. Is ‘ideal’ sitting posture real? Measurement of spinal curves in four sitting postures. Man Ther Aug; 14(4) :404-8

7.Elgueta-Cancino E et al 2014. A clinical test of lumbo-pelvic control: Development and reliability of a clinical test of dissociation of lumbo-pelvic and thoraco-lumbar motion Man Ther 19(5):418-424

8. Claeys K et al 2012. Altered preparatory pelvic control during sit-to-stance-to-sit movement in people with non-specific low back pain J Electromyography and Kinesiology Vol 22(6):821-828