Muscle Energy Technnique- MET
Muscle energy technique is a neuromuscular technique, it basically involves using participation on the part of the client to facilitate stretching of muscle tissue to return it to its normal resting length.
The way this works is by getting an isometric contraction (a contraction where the length of the muscle doesn’t change) in the muscle worked on, or the ones that do the opposite movement, which is held for a short time.
Neurologically this contraction allows the muscle spindles to ‘switch off’. Muscle spindles are specialised stretch receptors housed deep in the connective tissue of the muscle. When they sense the muscle lenghthening they cause a relfex which tones the muscle.
Normally this is useful as it helps prevent muscle tears and damage during activity, but when the muscles are injured or short it can also prevent lengthening, increase stiffness and impair function.
The contraction required is mild (normally not more that 20-30%) in order to engage only the muscle fibres most prone to shortening.
Reciprocal inhibition RI is the kind of MET which uses a contraction of the antagonist in order to release the tight muscle. This works especially well when the painful movement is acute as it means you are pushng away from the painful range.
It works because our bodies are neurologically set up to work efficiently. contracting the antagonist, that is the muscle that does the opposite of the one you want to stretch, helps ‘turn it own’ and facilitates lengthening.
Post Isometric relaxation PIR
Post Isometric relaxation works on a related but different principle. A contraction in the muscle you want to stretch which doesn’t change the length of the muscle (isomettric) when held for around 10 seconds leaves a window that allows the muscle to lengthen more. It seems to be that the contraction interferes with stretch receptors and deactivates them allowing the tissue to lengthen.
Slow Isotonic Eccentric Stretch of the Antagonist
SIESA MET is a recent innovation I believe was developed by my teacher Mark Gray, but it works on the same principle as the above. SIESA stands for Slow Isotonic Eccentric Stretch of the Antagonist. By activating the antagonist muscle in an eccentric contraction (where the muscle is contracting at a consistent level but lengthening) the muscle to be stretched (the agonist) is inhibited and more easily lengthened. This works especially well for muscles which are difficult to stretch normally like the deltoids, psoas and Iliacus.
References and further reading:
- Chaitow L. (2003) Muscle energy technique, London, Churchil Livingstone
- Chaitow L. & Delany J. (2005) Cliniacl application of Neuromuscular techniques Vol 1& 2. London, Churchill Livingstone.