What causes poor posture?

Anything that changes the function of the muscles, joints or nervous system will ultimately be reflected in a change in posture. This can be the result of many insults:

1) Poor Movement Habits

The body will adapt to any prolonged stress that is put on it. Exercise physiologists call this the ‘SAID’ principle or “Specific Adaptation to Imposed Demand”. This is usually thought of as a good thing; you go to the gym, you lift some heavy weights and your body adapts by building stronger bones and muscles.  However, this phenomenon can just as easily have negative effects. If, every time you go to the gym, you only work certain muscle groups or train with poor form you will be setting yourself up for muscle imbalance and injury down the road.

Another prime example is sitting. When you sit, certain muscle groups tend to shorten (eg: the pectoral muscles of the chest, the hip flexors and the hamstrings). If you are in the habit of sitting for extended periods, these muscles will eventually adopt a permanently-shortened condition which will wreak havoc on your movement quality and will predispose to injury.

2) Non-Optimal Early Development

The quality of development during the first few years has a big impact on structure and movement patterns in later life. Brain maturation during development leads to changes in how a baby’s muscles control its body, and these changes in muscle control lead to changes in bone structure, resulting in the typically shaped adult skeleton.  However, if development is compromised, which is estimated to occur in around 20-30% of the population, newborn patterns of muscle function and skeletal shape persist into adulthood. Learn more here.

This can lead to typical structural changes such as:

• Flat feet
• Knock knees
• Forward tilted pelvis
• Slumped spine

These structural issues lead to poor posture and movement patterns, resulting in more strain on the surrounding joints and increasing the risk of injury.

3) Protective patterns:

When a part of the body is damaged by injury or trauma, messages are sent from the site of injury to the brain. The brain analyses these messages and, if sufficiently threatening, they are interpreted as “pain” and defence mechanisms are triggered to prevent or to minimise further damage.   

Part of this reflex defence mechanism includes changing how certain muscles work. Some of the muscles tense and guard whilst others are inhibited (or tuned down). In the short term this works well to protect the area from further damage. However, in some instances, this protective pattern can persist long after the injury has healed. As Janet Travell M.D. White House Physician for John F Kennedy famously said:

“After an injury tissues heal, but muscles learn. They readily develop habits of guarding that outlast the injury.”

If these patterns do persist, movement will be compromised. A good example of this is after knee or ankle injury. We often see patients who, despite no longer being in pain, show significant residual deficits and poor movement on the previously injured side. A simple screen to assess lower quarter stability is the single leg balance test. To test this yourself stand on one leg with your arms crossed (not shown); you should be able to hold this position comfortably for 30 seconds eyes open and 10 seconds eyes closed. Make sure to check both sides.

 

4) Genetics and Structure

Our skeleton is shaped not only by development in the first years of life (as discussed above) but also via our genetics. An interesting illustration of this is in the sport of Olympic weight lifting. Eastern Europeans have long been dominant in the sport and one reason for this, according to Professor Stuart McGill of Waterloo University, is the shape of their hip sockets. Their genetically shallow hip sockets allow them to squat deeply without flexing their spine (which would otherwise predispose them to back injury).

5) Stress/ Emotional State

Stress elicits a sympathetic (“fright or flight”) response. This leads to a variety of changes in the body including increased tension in certain muscle groups. This pattern of increased tension is similar to that seen in the protective or newborn pattern with, for example, hiking of the shoulders. This is why you will often hear people say that “their stress goes straight to their shoulders”. If this stress persists for some time, the body may adapt and change the pattern of muscles it uses to move.

Images

• Leibenson, C. Rehabilitation of the Spine, 2nd Edition. (2007). Lippincott Williams and Wilkins. p 729-740

• Liebenson, C. (2001). Self-treatment of mid-thoracic dysfunction: a key link in the body axis. Journal of Bodywork & Movement Therapies, 3(5), 191-195.

Related articles

• Are you stomach gripping?
• What is good posture?
• Do YOU have good posture?
• How well do YOU breathe?

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This post was written by Steffen Toates. Steffen is a chiropractor at Dynamic Health Chiropractic in Jersey CI. For more information about Steffen click here.

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