What is the MET's? technique?

Muscle Energy Technique (MET) is an advanced type of stretch.

They aim to restore normal range of motion to tight muscles.

You may not feel very much during the technique but afterwards, the muscle group in question should feel more relaxed and stretchy. They may help to reduce muscle pain.

Muscle Energy Technique is used in conjunction with other techniques by sports massage therapists. Usually you wouldn’t have a treatment of only METs

METs are characterized by activating a muscle against resistance. The position of the muscle and force used can vary. Often the technique will finish by stretching the muscle in question, but this isn’t always necessary.

You can remember the sequence as this. Your therapist stretching your muscle, holding it for 30 or so seconds, then you actively resist against the stretch for 10 seconds to activate the muscle. You then take a deep breath, and on exhale your therapist will increase the stretch in the muscle, asking you about any pain present as they increase the stretch to a point of new resistance. This can be repeated as many times as necessary.