Posture and Stretching (Part 2): Muscles Locked-Short or Locked-Long?

Last time, we looked at how your posture is affected by how your nervous system remembers what is “normal” for you.  Your brain calibrates your muscle spindles (the muscle length detectors) so that your muscles know how long they should be at rest, and this is commonly how muscles can become chronically over-shortened (locked-short). The natural question to ask next is whether your muscles can become chronically over-lengthened (locked-long)? The answer is yes!

To understand what locked-long or locked-short muscle feels like, let’s think of a single muscle a bit like a modelling balloon. If we push on the ends of the balloon, it becomes shorter and fatter (and eventually like a pancake) with almost no space inside for the air. Similarly, if we pull on the ends of the balloon, it becomes longer and thinner (and eventually like a noodle), again with almost no space inside for air. This means the air is more pressurised, so in both cases, the ballon feels harder to the touch (more pressure inside) and the balloon skin feels more taut (to contain the air).

Like a chinese finger trap, pulling on the ends of a muscle causes it to become longer and narrower, squeezing and pressurising what is inside.

In reality, of course, muscles are filled with incompressible fluid rather than air, so we don’t have to shorten or lengthen muscle very much at all before the pressure inside rises quite significantly. Unfortunately this means that it is much harder to move blood in and out of the muscle, and so metabolic waste (which can irritate muscle tissue) cannot get out, and nutrients required to repair muscle tissue cannot get in, both of which can lead to aching muscles.

The usual solution for achy “tight” muscle is to try stretching it out. However, as we’ve seen, the fact that a muscle can feel “tight” to the touch actually means that the muscle feels harder (overpressurised) and the connective tissue surrounding it feels like it is pulled taut (to contain the increased pressure). We’ve also seen that this can occur if the muscle is locked-long as well as locked-short.  As a result, if the muscle is already locked-long, then stretching will only make the problem worse! As a result, we must first recognise whether a muscle is locked-long or locked-short.  Once this has been determined, treatment can be directed to help the muscles involved regain their natural shape, minimising the pressure inside, improving circulation, and allowing the tight, achy feeling to subside.

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