Muscle Energy Technique

“Muscle energy technique is a direct, non invasive manual therapy in which the therapist utilizes the barrier concept to position the patient’s body or part at their restrictive barrier followed by an isometric contraction & stretch to normalize joint dysfunction and increase ROM.”

HISTORY OF MET
FRED MITCHELL VIEW
In 1958 and then his son (mitchell et al 1979) have evolved a method in which the patient uses his/her muscles,on request from a precisely controlled position in a specific direction, against a distinctly executed counterforce. Some refinements were done by Karel lewit (1986) and Janda(1989)

SANDRA YALE VIEW
“MET is particularly effective in patients who have severe pain from acute somatic dysfunction such as those with a whiplash injury or a patient with severe muscle spasm from a fall . MET methods are also an excellent treatment modality for hospitalized or bedridden patients. They can be used in elder patients who may have severely restricted motion from arthritis or who have brittle osteoporotic bones”

PRINCIPLES
1) Law of Autogenic inhibition
“When a muscle is contracted isometrically this is followed by a period of relative hypotonicity, lasting for about 15 sec, during which a stretch of the tissues involved will be more easily achieved than before the contraction.”
2) Law of Reciprocal innervation
“During and following an isometric contraction of a muscle, its antagonist will be reciprocally inhibited, allowing tissues involved to be more easily strecthed.”



Law of Autogenic inhibition

Law of Reciprocal innervation

PROPRIOCEPTIVE MODEL OF DYSFUNCTION
If someone is bending forwards to lift something then abdominals are short of their normal resting length & extensors are stretched.
Korr (1947, 1975) says that because of their relaxed status, short of their resting length, there is silencing of the spindles.
However, due to a sudden demand for stability in this setting i.e. whatever was to be lifted unaccountably slips then a demand from a higher centers results in increased gamma gain reflexively.
As the muscle contracts rapidly to stabalise the alarm demands, the CNS would receive information that the muscle which is actually short of its neutral resting length was stretched.
This leads to inappropriate proprioceptor response muscles would have adopted a position of somatic dysfunction.
At the same time the stretched extensor muscles would rapidly shorten in order to stabalise the situation. In effect the two opposing sets of muscles would have adopted a stabalising posture to protect the threatened structures and in doing so would have become locked into positions of imbalance in relation to their normal function.

At this time any attempt to extend the area/joint would be strongly resisted by the tonically shortened flexor group. The individual would be locked into forward bending distorsion. Going further into flexion however would present no problems or pain.

NOCIOCEPTIVE MODEL (Van Buskirk’s)
Nocioceptors in a muscle are activated by minor trauma from a chemical,mechanical, thermal or other damaging stimuli.
Nocioceptive activation transmits impulses to other axons in the same nocioceptor as well as to the spinal cord.
peptide transmitters in the axon branches are released resulting in vasodilatation and the gathering of immune cells around the trauma site.

Direct mechanical restriction of the affected muscles derives from vasodilatation which, along with chemicals associated with injury – bradykinin, histamine, serotonin etc. – causes stimulation of local nocioceptors in muscle associated with the original trauma or those reflexively influences.
A new defensive muscular arrangement will develop which will cause imbalance and a shortening of the muscles involved.
After a matter of hours or days the abnormal joint positions which result from this defensive muscular activity become chronic as connective tissue reorganization involving tissue fibrocytes commences.
Connective tissue will be randomly oriented in the shortened muscle and less capable of handling stress.

HOW WOULD MET BE ABLE TO INFLUENCE THIS SITUATION?
In MET the skeletal muscles in the shortened area are initially stretched to the extent allowed by somatic dysfunction (to the barrier).
With the tissues held in this position the patient is instructed to contract the affected muscle voluntarily.
This isometric activation of muscle will stretch the internal connective tissues.
Voluntary activation of motor neurons to the same muscles also block transmission in spinal nocioceptive pathways.
Immediately following the isometric phase, passive extrinsic stretch is imposed, further lengthening the tissues towards normal easy neutral position.

HOW IS MET USED?
Concept of Ease and bind
Osteopathic pioneer H. V. Hoover (1969) describes ease as a state of equilibrium, or ‘neutral’, which the practitioner senses / or by having passive ‘listening’ contact in touch with the tissues being assessed.
Bind is opposite of ease and palpating the tissues surrounding, a joint which is taken towards the end of ROM – its resistance barrier
According to Goodridge – the barrier is not a pathological one but represents the first sign of resistance the place at which tissues require some degree of passive effort to move them.
We should try to note the moment at which we palpate the transition from one to the other, not to the extreme but where it begins.

Few questions which arise are:
Q. Why Patient’s voluntary contraction?
Ans. Repeated excitation of a pathway in CNS results gradually in easier transmission of nerve impulses through that pathway.this is brought about by a decrease in the synaptic resistance and is the basis of formation of correct habits and for learning.
Increase local blood flow and oxygenation

Q. Why lighter contractions ( i.e. 20% ) ?
Ans. It is considered that once a greater degree of strength than 25% of available force is used, recruitment is occurring of phasic muscle fibres, rather than the postural fibres which will have shortened and require stretching (Liebenson 1996).
It is far easier for the practitioner to control light contractions than strong ones, making MET a less arduous experience.
There is far less likelihood of provoking cramp, tissue damage or pain when light contractions rather than strong ones are used, making MET safer and gentler.
Karel Lewit (1999) have demonstrated that extremely light isometric contractions, utilizing breathing and eye movements alone, are often sufficient to produce PIR , and in this way to facilitate subsequent stretching.

Q. Why contraction is held for 7 to 10 seconds?
Ans. The contraction is held between 7 and 10 seconds as this time is necessary for the ‘load’ on the Golgi tendon organs to become active and to neurologically influence the intrafusal fibres of the muscle spindles,which inhibits muscle tone, so providing the opportunity for the area (muscle, joint) to be taken to a new resting length/resistance barrier with far less effort(Scariati 1991).

Q. What is the Role of breathing?
Ans. Muscle energy activity involves the holding of a breath during the contraction and the release of the breath as the new position or stretch is passively or actively adopted.
Cummings & Howell (1990) have looked at the influence of expiration on myofascial tension and have clearly demonstrated that there is a mechanical effect of respiration on resting myofascial tissue. Kisselkova, reported that non respiratory muscles receive input from the respiratory centres’
The abdominal muscles are assisted in their action during exhalation, especially against resistance
Movement into flexion of the lumbar and cervical spine is assisted by exhalation Movement into extension (i.e. straightening up from forward bending; bending backwards) of the lumbar and cervical spine is assisted by inhalation
Movement into extension of the thoracic spine is assisted by exhalation. Thoracic flexion is enhanced by inhalation
Rotation of the trunk in the seated position is enhanced by inhalation and inhibited by exhalation Neck traction (stretching) is easier during exhalation but lumbar traction (stretching) is eased by inhalation and retarded by exhalation.

Q How do we decide whether agonist or antagonist to be contracted?
Ans. ACUTE-RI ,CHRONIC-PIR

Q. Can the patient also participate in stretching?
Ans. Yes, it is preferred because it prevents a contraction of myotonic stretch reflex.
Patient errors during MET
Contraction is too hard (remedy: give specific guidelines, e.g. use only 20% of strength’, ).
Contraction is in the wrong direction (remedy: give simple but accurate instructions).
Contraction is not sustained for long enough (remedy: instruct the patient to hold the contraction until told to ease off, and give an idea ahead of time as to how long this will be).
The individual does not relax completely after the contraction (remedy: have them release and relax and then inhale and exhale once or twice, with the suggestion ‘now relax completely’).
Starting and/or finishing the contraction too hastily. There should be a slow build-up of force and a slow letting go; this is easily achieved if a rehearsal is carried out first to educate the patient into the methodology.

PRACTITIONER ERRORS IN APPLICATION OF MET :
1) Inaccurate control of position of joint or muscle in relation to the resistance barrier (remedy: have a clear image of what is required and apply it).
2) Inadequate counterforce to the contraction (remedy: meet and match the force in an isometric contraction; allow movement in an isotonic concentric contraction; and overcome the contraction in an isolytic manoeuvre).
3) Counterforce is applied in an inappropriate direction (remedy: ensure precise direction needed for best effect).
4) Moving to a new position too hastily after the contraction (there is usually more than 20 seconds of refractory muscle tone release during which time a new position can easily be adopted – haste is unnecessary and counterproductive).
5) Inadequate patient instruction is given (remedy: get the words right so that the patient can cooperate). Whenever force is applied by the patient in a particular direction, and when it is time to release that effort, the instruction must be to do so gradually.
6) The coinciding of the forces at the outset (patient and practitioner) as well as at release is important. The practitioner must be careful to use enough, but not too much, effort, and to ease off at the same time as the patient.
7) The practitioner fails to maintain the stretch position for a period of time which allows connective tissue to begin to lengthen (ideally 20–30 seconds, but certainly not just a few seconds)

GOALS OF MET
1.To lengthen tense muscle &fascia
2.To strengthen an asymmetrically weak muscle
3.To improve circulation ,respiration &N-M relationships.
4.To mobilize restricted joints.
5.To prepare joint for manipulation

INDICATIONS
a) Fibromyalgia
b) joint stiffness
c) stress and tension related problems
d) spinal & ribcage pain
e) chronic neck &back pain
f) migraine headaches
g) T-M joint pain
h) whiplash
i) sports injuries

CONTRAINDICATIONS
Acute inflammatory conditions
Malignancy
Aneurysm
Skin conditions
Recent major trauma
Infectious conditions
Disc herniation, fractures etc.