Physiology, Muscle Energy

Muscle energy technique (MET) is a type of osteopathic manipulative medicine developed by Fred Mitchell, Sr., DO. In 1948, Dr. Mitchell first described the kinematic motion of the pelvis. Building on this concept, and inspired by the neurophysiologist Charles Sherrington, Dr. Mitchell developed a modality to treat muscular action dysfunction by harnessing the patient's muscle action. Sherrington observed that contraction of an antagonistic muscle would help relax the agonistic muscle. He named the modality muscle energy, which was designed to improve musculoskeletal function by mobilizing joints and stretching tight muscles and fascia, thereby reducing pain and improving circulation and lymphatic flow.  MET can be applied to all body joints except the cranium. MET is a nontraumatic modality, and its application helps treat key lesions that are the root cause of many body dysfunctions. Understanding the intricacies of MET requires knowledge of human biomechanics; this knowledge can facilitate treatment with other modalities. For example, those with an in-depth understanding of human biomechanics can treat lesions typically addressed with a high-velocity, low-amplitude technique (HVLA) using less force and greater precision. Although Dr. Mitchell's initial concept of MET involved muscle activation with post-isometric relaxation, numerous other physiological principles for MET have since been developed. In today's MET, there are a total of 9 different physiological principles: crossed, extensor reflex, isolytic lengthening, isokinetic strengthening, joint mobilization using muscle force, respiratory assistance, oculocephalogyric reflex, reciprocal inhibition, muscle force in 1 region of the body to achieve movement in another, and post-isometric relaxation. Among the 9 approaches, post-isometric relaxation is the most commonly used. This will be discussed further below. MET is a safe technique that can be used with inpatients to reduce hospital stays. MET with post-isometric relaxation is generally contraindicated in patients with low vitality, certain postsurgical patients, or those in the ICU. They would benefit from MET using reciprocal inhibition, respiratory assist, or the oculocephlogyric reflex.  Patients with a history of eye surgery are contraindicated for MET with oculocephalogyric reflex. As the treatment requires patient cooperation, patients should be able to understand and communicate easily with the clinician. Complications can be avoided if clinicians correctly diagnose, localize lesions, and apply appropriate force. Understanding muscle physiology is essential for MET. There are 4 types of muscle contraction: isometric, concentric, eccentric, and isolytic. Isometric contraction occurs when the muscles contract without the origin and insertion of the muscles approaching each other. Concentric contraction occurs when muscles shorten during contraction. Eccentric contraction is when the muscle lengthens with contraction, and isolytic contraction is when an external force lengthens the muscle contraction. The physiology of muscle contractions best explains the mechanism of action in MET.