Changing your posture can be a tricky business. All too often we try not to make ourselves crane our necks forwards while we work at our computers, or try not to let our shoulders rise when we are stressed. Does it work? If only it were that simple! So why is it that trying to change our posture is so difficult?
To understand this, we need to understand why we have a typical posture at all. Our muscles have length detectors (called muscle spindles) embedded inside them (actually, they are embedded in the fascia which runs through the muscle). This allows your brain to know how long each muscle is, relative to what the length detector thinks is “normal” for that muscle. As a result, a muscle will reflexively contract to protect itself if a rapid overstretch is detected. However, if the length of a muscle is slowly increased, the brain recalibrates the length detectors to this new “normal” length, such that the protective contraction is not provoked. This is exactly why sitting hunched at a desk for a long time can actually alter your posture – the muscles overstretch slowly, the length detectors are recalibrated, and the brain believes that your hunched posture is now “normal”.
In many cases, pulling or pushing harder against resistance does not make it better.
The key, of course, is that this recalibration only happens if muscles are stretched slowly. As a result, trying to fix your posture by standing to attention and holding it can often be counter-productive. This is because the movement of standing to attention is too quick, causing the muscles you are trying to lengthen to rapidly overstretch, provoking a reflexive contraction. This means that unless you try to correct your posture slowly enough, you will end up contracting the very muscles you are trying to lengthen!
All of this means that our postural “memory” is really stored in the length detectors and the brain rather than in our muscles. As a result, pulling against muscles to make them longer, or doing the opposite movement to the posture you are stuck in is unlikely to achieve lasting results because immediately afterwards, the postural memory will reassert itself, moving you back to your habitual posture.
Strangely enough, this means that if you do want to achieve lasting postural improvement, you have to use slow and gentle movements which create a sense of letting go rather than a sense of tension or strength, because only through this can your brain and muscle length detectors accept these changes as permanent.
