Muscle Energy Technique (MET)

Having a tight muscle almost always translates into joint stiffness. Back in the days, Osteopaths developed a clever technique of restoring a muscle’s ‘normal’ length to prepare clients for joint manipulation. Once the surrounding soft tissues are sufficiently released, the chances of comfortable and successful joint manipulation are much higher.

The Muscle Energy Technique (MET) affects beneficial change for the client by using the energy of their own contracting muscles. It “targets the soft tissues primarily, although it also makes a major contribution toward joint mobilisation” (Chaitow, 1996, p1).
 
MET can be used as a standalone technique or intelligently integrated into a complete soft tissue session that includes other techniques as well. Muscles tend to respond far better to MET once they’ve been warmed up with massage. Additionally, this would have allowed the therapist to identify tight areas that are likely to need more attention.
 
MET aims to restore the ‘normal’ length of tight, hypertonic muscles and address areas of scarring or adhesions. As such, it does not attempt to increase muscle length beyond what is normal and functional for the individual but merely to restore. This means that they only work where there is a real and noticeable restriction in the tissues.
 
Benefits
 
MET helps restore the tone of the muscle by using its innate capacity to contract and relax. It also helps strengthen the treated muscle by restoring its normal length and thus increasing its contractile potential. By normalising muscle length, it is an effective preparation for further stretching. MET increases joint mobility by normalising the length and tone of the surrounding soft tissues. It also boosts local circulation and improves musculoskeletal functioning in general.
 
Although the effects of MET are quick and dramatic, it is recommended to maintain and/or continue the progress by incorporating regular stretching.
 
How MET works
 
All muscle energy techniques are based on two different phenomena occurring in the neuromuscular system that promote a temporary relaxation response. 
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Post Isometric Relaxation is the first key phenomena enabling MET. “Following a [6-8 second] isometric contraction … there is a refractory, or latency period of approximately 15 seconds during which there can be an easier movement (lengthening) towards the new position of a joint or muscle” (Chaitow, 1996, p5). After the isometric contraction, the muscle becomes inhibited and more relaxed and can be more easily stretched to a new resting length.
 
Experience shows that a very mild contraction with 5-20% of one’s strength is absolutely sufficient and more effective than a stronger one at achieving the desired outcome.
 
The PIR manoeuvre involves the following steps:

• The client needs to be positioned in a way that would allow the progressive lengthening of the target muscle in a position of reasonable comfort for themselves and the therapist.
• The target muscle is then lengthened to the point where the client experiences a mild but noticeable tension. This ‘point of bind’ or ‘muscle barrier’ is the level where there is a mild sensation in the muscle fibres but they are not yet getting stretched.
• This position is maintained until the client relaxes into it.
• Next, the client is asked to contract their muscle by matching the resistance of the therapist using about 5-20% of their strength. The opposing forces of the therapist’s press and the client’s resistance create the isometric contraction of the muscle.
• The isometric contraction is held for 6-8 seconds, which is sufficient to trigger the desired relaxation response.
• Next, the client is asked to relax the contraction with a deep long exhale.
• As the therapist feels the release of tension in the muscles in the following seconds, they will smoothly lengthen the muscle to the new point of bind.
• The new lengthened position is held for 20 seconds to allow the neuromuscular system to accept is as normal.
• The procedure is repeated, usually 2-3 times, reaching a progressively longer muscle length and holding each new position of bind for 20 seconds.
• The final barrier position reached is held for 30 seconds.
• Finally, the muscle is passively returned to its neutral resting position.

 
This manoeuvre is possible due to the inverse stretch reflex which causes the muscle to relax. It is mediated by the Golgi Tendon Organs (GTOs) that monitor the load on the tendon. They would cause the muscle to relax through neurological inhibition once a certain load threshold is reached. This reduces the risk of muscle tear during contraction.
 
It is worth noting and remembering that the PIR technique is not to be used with muscles that are recovering from a recent trauma. It can be overwhelming for the recovering fibres and cause them to re-tear.

Reciprocal Inhibition (RI) is based on the agonist/antagonist muscle relationship. When a muscle contracts, the one opposing it will relax through an automatic inhibition. This effect enables the comfortable lengthening of a tight hypertonic muscle by contracting the one opposing it.
 
Unlike, PIR, in RI the lengthening needs to occur simultaneously with the contraction of the opposing muscle because as soon as it stops the effect is lost.
 
There are two basic methods of using RI to good effect.
 
Passive

• The target muscle is passively taken to the position of bind.
• The client then isometrically contracts the antagonist of the target muscle gently (5-20 % of their strength) for 6-8 seconds against a resistance provided by the therapist.
• The client then relaxes and the therapist immediately lengthens the muscle smoothly to a new barrier.
• The client relaxes fully in the new ‘normal’ position for ~ 20 seconds.
• The process is repeated several times (2-3 usually) and the final barrier is held for ~30seconds.

 
Active

• The client actively lengthens the target muscle to the barrier position by contracting its agonist.
• The client rests with support from the therapist in this position for ~20 seconds.
• The client then lengthens the target muscle further by contracting its antagonist to a new position of bind.
• The procedure is repeated several times and the final barrier is held for ~30 seconds.

 
RI is triggered by using the body’s stretch reflexes. A myotatic stretch reflex, for example, prevents lengthening the muscle too quickly or too far. Proprioceptors in the muscles known as muscle spindle cells monitor the rate of change in length and tension in the muscle. When a threshold is reached, they will cause a spontaneous contraction in the muscle to prevent over stretching.
 
Especially the active RI is safer in treating gentler areas like the neck or when working with clients after recent injuries. This is because the client has greater control and the body’s natural preservation reflexes are likely to stop them before causing any damage. 
 
A healthy antagonist can be contracted in a reasonably shortened position to enable the stretch of the target muscle. Care is needed here to avoid a spasm when contracting an already shortened muscle. This is one of the potential limitations of the active RI method.
 
Combining PIR with RI
 
The two methods can be combined in order to produce a very quick and effective muscle lengthening. When used jointly they usually yield the maximum achievable result for the session with just one repetition.

• Either passively lengthen (PIR) the target muscle to a position of bind or get the client to reach it with an active contraction of the antagonist.
• The client is asked to contract isometrically (PIR) against resistance offered by the therapist.
• The client then actively lengthens (RI) the target muscle to a new barrier by contracting the antagonist.

 
This combined approach is hugely effective but it requires a very clear and precise communication so that the client can comply with the instructions.
 
Important considerations

• Communication between the therapist and the client is a fundamental part of successfully applying an MET. It is important to use simple but clear and precise instructions when guiding the client through the manoeuvres. Also, it is important to help them feel as relaxed and comfortable as possible by using the appropriate tone and softer words.
• Breathing and the exhale in particular play a crucial role. It is easier and more comfortable to stretch the muscle on an outbreath. During this phase of breathing the parasympathetic nervous system, which promotes relaxation is preferentially activated.
• Positioning the client’s body must achieve several goals: it must be comfortable for the therapist and the client, it must allow sufficient range of motion of the target muscle, ideally, it must isolate the target muscle so that it is the only one being stretched. 

MET can be an invaluable tool in the arsenal of a soft tissue therapist relieving clients' discomfort safely and effectively.