MET

BY CLAIRE FARQUHARSON, CHARTERED PHYSIOTHERAPIST AND SENIOR LECTURER IN SPORTS THERAPY

VERSUS INTRODUCTION

PNF WHAT, WHEN AND HOW?

Both MET (muscle energy technique) and PNF (proprioceptive neuromuscular facilitation) are perceived as effective manual techniques, but for many therapists there is still some confusion about them. This article aims to clarify the theory behind both, explaining what they involve, when they should be used, and how they should be carried out. Stretching is a primary tool for preventing injury, but it is vital for clinicians to understand how stretches are correctly applied. The outcome to improve flexibility is the same with MET and PNF, but there are a number of important differences in their clinical application. The lack of consensus among studies, combined with the development of both techniques at a similar time, has resulted in a blurring of their definitions and an overlap between the two in many studies. As well as comparing the techniques of MET and PNF, this article will examine the current evidence base for each.

Muscle flexibility is an important aspect of human function, therefore limited flexibility predisposes a person to a variety of injuries, from muscle strains to more serious injuries such as a stress fracture (1). Many clinicians advocate a variety of stretching techniques as a primary tool to prevent impairment of functional activities, by regaining or maintaining muscle flexibility and avoiding a decrease in the range of movement (ROM) (2,3). Although the majority of authors specify different stretching techniques, such as static, dynamic, ballistic, active, passive, isometric, proprioceptive neuromuscular facilitation (PNF) or muscle energy technique (MET), no single technique has been advocated as being more effective (2–6). Within the field of manual therapy, MET and PNF are

key areas taught in many educational programmes as an effective technique, as through a single procedure many therapeutic outcomes can be achieved (7). However as both techniques have become more widespread in both teaching and clinical practice it is vital that we as clinicians understand the techniques involved, to ensure that they are applied effectively.

WHAT IS MET?

Generally there is a lack of consensus on the definition of MET. Many researchers adopt the preferred modern definition (8), namely that it involves“the voluntary contraction of the muscle in a precisely controlled direction, at varying levels of intensity, against a distinctly executed counterforce applied by the operator”.

Research suggests that MET not only lengthens the contracted or spastic muscle, but it also strengthens physiologically weakened muscles. In addition to this, it also reduces localised oedema by acting as a lymphatic or venous pump to aid the drainage of fluid or blood, and mobilising the range of movement of a joint with restricted mobility. With respect to altering muscle length, MET is based on the recruitment of postural muscles which are more susceptible to shortening and require stretching (9).

WHAT IS PNF?

PNF is a manual resistance technique which works by simulating fundamental patterns of movement to oppose motion in multiple planes concurrently. Initially used for stroke victims and children with cerebral palsy, it is now commonly used to treat a broad range of orthopaedic conditions (10). The goal of PNF is to promote functional movement through facilitation, inhibition, strengthening and relaxation of muscle groups. The technique uses concentric, eccentric and static muscle contractions. These muscle contractions with properly graded resistance are combined and adjusted to fit the needs of each patient.

HISTORY OF MET AND PNF Although the outcome of improved flexibility is the same in both MET and PNF, there are a number of differences

12 sportEX dynamics 2010;25(Jul):12-16