Efficacy of Muscle Energy Technique and Myofascial Release in Nonspecific Low Back Pain—A Comparative Study

Introduction

Nonspecific low back pain (LBP) is defined as LBP that is not attributed to a recognizable known specific pathology, for example, infection, tumor, osteoporosis, ankylosing spondylitis, fracture, inflammatory process, radicular syndrome, or cauda equina syndrome. ¹

Specific LBP and LBP with neurocompressive signs represent ∼20% of LBP in primary care. The remaining 80% cannot be definitively linked to a specific cause and is described as nonspecific LBP. ² The term “nonspecific” indicates that no precise structure has been identified causing the pain. Nonspecific LBP includes diagnoses such as lumbago, myofascial syndromes, muscle spasm, mechanical LBP, and back sprain. It is thought that in some cases the cause may be a sprain (an overstretch) of a ligament or muscle. In other cases, the cause may be minor problems in the structures and tissues of the lower back that result in pain. However, it may be challenging for a practitioner to know precisely where the pain is coming from, or what exactly is causing the pain. ¹

Physical therapy interventions for LBP consist of many options, including manual therapy, exercises, and electrotherapeutic modalities. Manual therapy includes techniques such as muscle energy technique (MET), myofascial release (MFR), and trigger point release. Although considered a manual therapy, MET is not particularly a mobilization or manipulation technique. MET is an active technique in which the subject, rather than the therapist, provides corrective force. Greenman defined MET as a “manual medicine treatment procedure that involves the voluntary contraction of the subject's muscle in a precisely controlled direction, at varying levels of intensity, against a distinctly executed counterforce applied by the therapist.” It has been hypothesized that MET can be used to lengthen and strengthen muscles, to increase fluid mechanics and decrease local edema, and to mobilize a restricted articulation. ³ MFR can be defined as “the facilitation of mechanical, neural, and psychophysiological adaptive potentials as interfaced via the myofascial system.” ⁴

Although many clinicians use these techniques successfully for their patients, there is a lack of strong or significant evidence on which techniques are preferred for certain conditions and a lack of literature on the comparison between MET and MFR in patients with nonspecific LBP. The objective of this study was to compare the effects of these two forms of soft tissue mobilization in patients with nonspecific LBP.

Methods

In this comparative study, subjects were recruited from Dolphin (PG) Institute of Biomedical and Natural Sciences, Dehradun, Uttarakhand, India. Thirty-one subjects were chosen per the inclusion and exclusion criteria, and informed consent was obtained from all subjects after explaining the procedure. Pain and disability were measured using the visual analog scale (VAS) and Oswestry Disability Index (ODI) before the intervention, and subjects were divided into two groups randomly by the chit method. The total number of sessions was seven for each group. On the eighth session, postintervention data were collected and called for follow-up after 21 days. In group A, MFR was applied to the quadratus lumborum and the erector spinae muscles for three repetitions, maintaining a light pressure to stretch the barrier for approximately three to five minutes. In group B, MET was applied to the quadratus lumborum and the erector spinae muscles for five repetitions, with a 7- to 10-second hold.

Results

SPSS 13 software was used for data analysis. The statistical significance was set at a P-value of 0.05 (95% confidence interval). The mean and standard deviation (SD) for both groups were shown with VAS and ODI as the outcome measures in Tables 1 and 2. Both groups showed a significant difference in the mean and SD, showing the efficacy of both techniques.

Paired t-test was used for analysis of data within the group and independent t-test was used for the analysis of data between the groups shown in Tables 3 and 4. It is seen from the analysis that the t-value of Group A is less than Group B considering the findings on the basis of the VAS and ODI scale.

Discussion

Results of this study showed that there was a considerable effect of MET on the quadratus lumborum and erector spinae muscles in decreasing pain and disability in patients with nonspecific LBP as compared with patients who received MFR. Both MET and MFR reduced pain and disability after treatment; however, after a 21-day follow-up it was found that MET was more effective.

MET uses isometric or isotonic contractions as a way of lengthening tight muscle, strengthening weak muscle, mobilizing joints, and relieving congestion in the tissues. Postisometric relaxation MET refers to the subsequent reduction in tone of the agonist muscle after isometric contraction. This occurs due to stretch receptors (Golgi tendon organs) located in the tendon of the agonist muscle. These receptors react to overstretching of the muscle by inhibiting further muscle contraction. This is naturally a protective reaction, preventing rupture, and has a lengthening effect due to the sudden relaxation of the entire muscle under stretch. In more technical terms, a strong muscle contraction against equal counterforce triggers the Golgi tendon organ. The afferent nerve impulse from the Golgi tendon organ enters the dorsal root of the spinal cord and meets with an inhibitory motor neuron. This stops the discharge of the efferent motor neuron's impulse and, therefore, prevents further contraction, the muscle tone decreases, which in turn results in the agonist relaxing and lengthening. ³

With MET, the touch of the clinician, along with stimulation of agonist and antagonist muscles, seems to alter perception of pain. This technique could be performed before other rehabilitation techniques, such as strengthening exercises, to decrease pain and allow for more efficient exercises to be performed. This technique may be better than others in decreasing pain for several reasons. The time it takes to administer MET is very short. It also allows the clinician to have physical contact with the patient, helping the patient to trust the clinician. Finally, MET is a low-force isometric contraction in a pain-free position. This technique can be accomplished without causing further pain or harm to the patient. ⁵

High-quality research on the mechanism of action of MFR is lacking. It has recently been proposed that the mechanisms of MFR (tensegrity and thixotropism) are based on changes to the architecture and functional state of the myofascial system. The purpose of MFR is to release deep layer restrictions of soft tissues by application of constant pressure. The changes may be due to pressure-induced effects that may lead to a local muscle response characterized by a decrease in amplitude and rate of motor unit recruitment, which may be associated with reduced pain. ⁶

Morales et al. concluded that massage reduces electromyography amplitude and vigor when applied as a passive recovery technique after a high-intensity exercise protocol. Massage may induce a transient loss of muscle strength or a change in the muscle fiber tension–length relationship, influenced by alterations of muscle function and a psychological state of relaxation. ⁷

Conclusion

Although both MET and MFR were effective in reducing pain and disability after treatment in patients with nonspecific LBP, it was found that after follow-up, MET was more effective. Moreover, these forms of manual therapy not only reduce pain but are also time- and cost-effective.