Understanding Posture

What is ‘posture’?

Posture is the alignment and position your body adopts at any given moment based on what your brain is telling it to do.  A good way to think of posture is that it is your ‘default’ position at any moment. 

For clarity, posture is usually thought of as a ‘static’ standing posture.  In reality you have a static sitting, standing, carrying (holding something in your arms), listening, speaking posture and many more.  In this folder at ptdirect we talk of posture as the ‘static’ situation and movement patterns as the ‘dynamic’ situation.  However technically at any moment in a movement you could assess someone’s posture by taking a snapshot of the body.

As mentioned you have a lot of different maps of static posture in the mid brain part of your CNS (somatic motor centres located in the midbrain are involved in the regulation of walking, posture and of reflexes for head and eye movements).   Here we will just look at sitting and standing as examples to help you understand how posture works.

Why assess posture?

The idea behind assessing posture is that it gives us insight into the ‘default’ positions that the body has mapped.  This default position is learnt over time and is a result of the brain finding the best way it can to cope with the situations it is asked to endure (in terms of posture) and the hardware it has available to do that (the musculoskeletal system). 

Another way to look at it is that posture is a symptom of both your environment and the way you’ve learnt to position yourself to deal with it, given the condition of your musculoskeletal system at the time. 

An example would be if you sat at a desk a lot your sitting posture will have developed based on whether you are reading, typing or slumped over paper writing notes and the ability of your body to hold any one of those postures.

The significant thing is that posture is mapped into the mid-brain centres of the CNS over time and therefore becomes a subconscious reflection of all that has been experienced by the body over time.  This has implications as to how we attempt to deal with ‘poor posture’ and encourage ‘good posture’.

Posture is also self perpetuating because any new posture struck consistently causes a gradual changing of the subconscious map of that posture and encourages the hardware (musculoskeletal system) to adapt to that position more readily.

A stark example of this is the forward head posture that people seem to develop over time sitting and stooping at desks or from musculoskeletal distress (injury).  This posture becomes reinforced and as a result the dowagers hump (that build up of connective tissue at the base of the neck) begins developing to cope with the load created by the head not sitting squarely on top of the neck joint.  Over time this connective tissue thickens and becomes stiff, essentially reinforcing the position and actually making correction of the position very difficult.  You should also note that many of the initial issues that create this forward head posture occur at the pelvis and lumbar area and are simply dramatically expressed at the neck – another example of the human kinetic chain in action.

Why static postures are only a snapshot

Static posture at any moment is a snapshot.  Heck, anyone can get into a good posture for a moment or two.  What is most interesting to see is someone’s posture when they are tired or don’t know you are looking them over.

To review someone’s posture you want to assess what their subconscious map for a posture is (which means you want to keep their conscious mind out of it – so don’t tell them what you’re up to).  You want to know what the map defaults to when that initial posture is struck for a while.  This gives you evidence of the musculoskeletal system’s ability to execute the map it has of that posture and what the brain then allows to happen when the sensory nervous system feeds back that the posture is tiring and change is needed to relieve the muscles. 

This final position, where fatigue from standing still or sitting for a while sets in, is the true default postural position your client may be in the most.  Sometimes it’s not too pretty.

What dictates static posture in any one position

The four main things that dictate a person’s static posture are;

1. What map is being recalled (sitting, standing, talking, listening etc)
2. What the default position is for that map (remember this has been learned over time)
3. The condition of the musculoskeletal system at the time
4. The duration of time that the position has to be held

Points 1 and 2 are fairly self explanatory so we will concentrate on points 3 and 4 here.

What is good posture

Let’s look at standing posture as an example.  Above is a diagram of ‘good posture’ as viewed from side on.

Here are the various types of standing posture that have also been modelled.

You can see in posture one the load of gravity is passing through the joints and the bony alignment of the joints and the line of the rigid and strong bones are optimally used to take the load.

What are the issues with poor posture

In the other three postures (kyphotic-lordotic, flat back, sway back) you can see there is a deviation from ideal alignment.  All deviations create load in the muscles and connective tissue and as such require contractions, thickening or a changing of the posture to one with less work involved (e.g. standing to sitting or slinging etc). 

Poor posture over time can cause deterioration in the musculoskeletal system’s health and this cascades into other systems such as the nervous and endocrine systems.  An example is that slumped standing and sitting can decrease bowel motility (movement) and result in diarrhoea or constipation and can also cause sciatica (sciatic nerve impingement).  Fundamentally having good posture improves your health and well being.