Posture and Comfort

by Hugh Babington Smith

What is posture?

A posture is a static state (however short or long)– ‘a position of the body’, ‘an attitude’, or ‘arrested movement’. But it is far more than just a description of a position at any one time. In every day life, it is a word which is often qualified by adjectives such as defensive, poor, bad, aggressive or happy. That which distinguishes posture from position is the inclusion of the mental element, particularly of mood or emotion, as an ingredient. Furthermore, it is very important to understand that this mental ingredient can be passive or active, it can be affected by the physical posture or, the other way round, can determine the physical posture.

This is why the word ‘posture’ is used widely: even within this online resource it crops up in 27 topics other than this one! A quick glance at these other topics shows that they are largely those covering relationships with other human beings. The message is usually, ‘Get your posture right, and you will find this relationship/task/activity easier to manage’. Well, this topic – posture and comfort – aims to give meaning to the sentiment of ‘Getting your posture right’.

We always have a posture of some kind or another, even if the mental intention behind it is subconscious. And, of course, it is well documented that body language plays a large part in communication. Our bones hold us up, our joints link our bones, our muscles move the bones around the joints, our nerves facilitate control of the whole and the whole process is controlled by the mind. The key to good posture is understanding and being able to implement correct joint alignment; however, muscle activity, balance and nerves are all part of the picture.

The mental element

Within the context of this topic on posture and comfort, the key understanding to take away is that whilst the relationship between the mental and the physical is two way, changing the emphasis to being mainly or only active is a matter of will, knowledge and developing the right habits. There is no need to have a posture which causes you pain or discomfort. You can apply this principle using the information in this article and/or in conjunction with the other topics.

What is not easy, though, is being sure that the direction of your habit change is correct, and you may well need professional help in achieving this.

Joint alignment

Some joints, such as those on the arms or legs, are highly visible, but the word joint also applies to any link between bones, including the spine, shoulders and hips and weight-bearing joints in the feet. There are in fact about 230 mobile and semi-mobile joints in the body.

Our bodies evolved for certain purposes and our joints move in particular ways to fulfil those purposes most efficiently. When alignment is ‘correct’ – that is, in the evolved position – our body is in balance and our muscles and joints are working with least effort.

This actually applies to movement as well as static posture. Professional athletes go to great lengths to understand and apply this, for then their bodies are not just in balance but achieving maximum output as well. If our joints are used differently from their ‘designed’ position, we say they are out of alignment or malaligned. One effect of using joints out of alignment is discomfort, which can manifest as pain and eventually become injury.

The degree of malalignment matters: a very slight amount and the effect is not immediately serious; a greater degree and we know about it instantly. If a joint is malaligned and under stress, something gives, and a break or a tear ensues. ‘Something’ can give quickly or, if the stress is at lower level but repetitive, over a period of time – hence repetitive strain injury (RSI). This can occur anywhere in the body. (It should be noted, though, that the strain in RSI need not come just from incorrect alignment, but can result from excessive movement, even if in correct alignment.)

Malalignment leads to muscle imbalance. Muscles adapt: for instance, an arm in plaster cannot be stretched immediately when the plaster comes off. The same effect happens when a joint is held in the wrong position over a period of time, which is why some people have round backs or slumped shoulders.

Muscle activity

For the purposes of this discussion, there are two kinds of skeletal muscle in the body, each with their own function. The first kind – the postural or ‘slow twitch’ muscle – holds us in position. These muscles are short and in the deepest layers, especially along the spine. The other kind – movement or ‘fast twitch’ muscles – are for moving us. These lie over several joints and are closer to the surface than slow twitch muscles. We need both in varying degrees to perform properly.

(The other kinds of muscle are cardiac – the heart – and smooth muscles, which function automatically, running the digestive tract and so on.)

Even postural muscles will not hold positions for any length of time unless they are used regularly, a good reason in itself for sedentary workers to take exercise and understand alignment.

The phrase ‘muscle tone’ in physiotherapy refers to the amount of fibres in the muscle ‘firing’ at any one time. Even at rest, some fibres are firing and the muscle is ‘ready to go’. Only when a body is dead is there no muscle tone. The amount of muscle tone in a posture is largely a function of the amount of support being provided. At an extreme, a person lying on their back has a wide support base, so minimum muscle tone. At the other extreme, a person standing on tiptoes on one leg has a very narrow base and so needs maximum muscle tone in perfect alignment.

The muscles are, of course, governed by the brain: lift an empty box that you believe to be full, and it shoots up into the air as your brain orders too many muscle fibres to fire for the task.

Balance

A contributory factor to holding a posture is balance. Balance can have two meanings when referring to posture. It can mean the balance of opposing forces: for instance, are the muscles holding the shoulders back strong enough in comparison with those pulling the shoulders forward? If not, then a round back is likely to happen. Secondly, it can mean balance in the sense that if it is not right, the person falls over.

A person with good muscle balance will be able to hold an unstable position for longer because they recruit the postural muscles in the correct alignment and their movement muscles are less involved. A person with poor balance will move a lot and have to use the movement muscles to try to get back to balance. These muscles will get tired quickly and the correct posture will be lost.

Nerves

We control our movement through our nerves. Messages are passed in both directions between the brain, to and from the extremities, the muscles and the joints. If this passage of information is disturbed, we cannot have proper movement. Nerves are physical entities and just as subject to maltreatment as bones and muscle; they can be affected by blows, by stretching, by pressure, by twisting. They pass between muscles, along bones and joints on paths developed, like the rest of the system, during evolution. So again it follows that if alignment is not right, the nerves may be affected.

Ergonomics

One factor that has a great effect on our posture is the way our environment is designed, because that affects how we need to interact with it in order to get things done.

Ergonomics, as defined by the Institute of Ergonomics & Human Factors (the professional association of ergonomists), is ‘...about designing for people, wherever they interact with products, systems or processes...’.

As a discipline, it originated in World War II, when scientists developing new equipment realised the importance of considering the user.

Note

Posture is not the same as ergonomics

While ergonomics might have played a part in the original design of your office furniture and equipment, or the layout of your business processes, what the normal office worker means by ‘workplace ergonomics’ or ‘office ergonomics’ is actually ‘How do I keep comfortable in my working environment?’ or, ‘Will it get rid of my aches and pains?’ The answers to these questions are more often a matter of posture than of ergonomics. Well-designed equipment will make it easier to adopt good posture, but the posture still ‘belongs’ to the user.

But it is not just shape – designing a fighter cockpit or a fast car requires understanding how vision and hearing interact with the environment in very stressful conditions. Planning an airport that will handle thousands of passengers a day over very long periods requires knowledge of how human beings interact with their environment and each other – so psychology has a part to play.

While an ergonomist can analyse what is there, their skills are much better used in analysing plans and intentions and helping with the design. With a complex design, whether small or large, it is far easier to get it right early in the design stage than later on.

Example

Not taking account of the user in design can have strange results: an intelligence analysis of a captured Soviet tank in the mid-1970s concluded that the ideal crewman would be just under a metre tall with an arm span of 2.5 metres...