Continuing Education Activity

The McKenzie back exercises belong to an exercise protocol pioneered by physiotherapist Robin Anthony McKenzie in the 1950s and popularized around 1985.The McKenzie method, also known as Mechanical Diagnosis and Therapy (MDT), is widely used as a classification system for the diagnosis and treatment of a variety of musculoskeletal conditions, including lower back, neck, and extremity pain. Over time the McKenzie exercises have become synonymous with spinal extension exercises, as opposed to Williams exercises (named after Dr. Paul C. Williams) which have become synonymous with lumbar flexion exercises. The McKenzie method has wide acceptance as an effective program for back pain. It stressed self-treatment through posture correction and repeated exercises movements at end-range performed with high frequency. This activity describes the McKenzie Back exercises, their indications, and highlights the role of the healthcare worker in the management of patients with low back pain.

Objectives:

• Describe the classification of back pain.
• Review the indications for McKenzie back exercise.
• Summarize the clinical significance of the McKenzie back exercises.
• Outline the importance of improving care coordination among interprofessional team members by teaching patients with back pain how to perform McKenzie Back Exercises.

Introduction

The McKenzie back exercises belong to an exercise protocol pioneered by physiotherapist Robin Anthony McKenzie in the 1950s and popularized around 1985.[1] The McKenzie method, also known as Mechanical Diagnosis and Therapy (MDT), is widely used as a classification system for the diagnosis and treatment of a variety of musculoskeletal conditions, including lower back, neck, and extremity pain.[2] Over time the McKenzie exercises have become synonymous with spinal extension exercises, as opposed to Williams exercises (named after Dr. Paul C. Williams) which have become synonymous with lumbar flexion exercises.

The McKenzie method has wide acceptance as an effective program for back pain. It stresses self-treatment through posture correction and repeated exercise movements at end-range performed with high frequency.[3] The hallmark of the McKenzie method for back pain involves the identification and classification of nonspecific spinal pain into homogenous subgroups. These subgroups are based on the similar responses of a patient's symptoms when subjected to mechanical forces.[4] The subgroups include postural syndrome, dysfunction syndrome, derangement syndrome, or “other,” with treatment plans directed to each subgroup.[5] The McKenzie method emphasizes the centralization phenomenon in the assessment and treatment of spinal pain, in which pain originating from the spine refers distally, and through targeted repetitive movements the pain migrates back toward the spine.[4] The clinician will then use the information obtained from this assessment to prescribe specific exercises and advise on which postures to adopt or avoid. Through an individualized treatment program, the patient will perform specific exercises at home approximately ten times per day, as opposed to 1 or 2 physical therapy visits per week. According to the McKenzie method, if there is no restoration of normal function, tissue healing will not occur, and the problem will persist.

Classification:

The postural syndrome is pain which is caused by mechanical deformation of soft tissue or vasculature arising from prolonged postural stresses. These may affect the joint surfaces, muscles, or tendons, and can occur in sitting, standing or lying. Pain may be reproducible when such individuals maintain positions or postures for sustained periods. Repeated movements should not affect symptoms, and relief of pain typically occurs immediately following the correction of abnormal posture.[5]

The dysfunction syndrome is pain which is caused by the mechanical deformation of structurally impaired soft tissue; this may be due to traumatic, inflammatory, or degenerative processes, causing tissue contraction, scarring, adhesion, or adaptive shortening. The hallmark is a loss of movement and pain at the end range of motion. Dysfunction has subsyndromes based upon the end-range direction that elicits this pain: flexion, extension, side-glide, multidirectional, adherent nerve root, and nerve root entrapment subsyndromes. Successful treatment focuses on patient education and mobilization exercises that focus on the direction of the dysfunction/direction of pain. The goal is on tissue remodeling which can be a prolonged process.

The derangement syndrome is the most commonly encountered pain syndrome, reported in one study to have a prevalence as high as 78% of patients classified by the McKenzie method.[6] It is caused by an internal dislocation of articular tissue, causing a disturbance in the normal position of affected joint surfaces, deforming the capsule, and periarticular supportive ligaments. This derangement will both generate pain and obstruct movement in the direction of the displacement. There are seven different subsyndromes which are classified by the location of pain and the presence, or absence, of deformities. Pain is typically elicited by provocative assessment movements, such as flexion or extension of the spine. The centralization and peripheralization of symptoms can only occur in the derangement syndrome. Thus the treatment for derangement syndrome focuses on repeated movement in a single direction that causes a gradual reduction in pain. Studies have shown approximately anywhere between 58% to 91% prevalence of centralization of lower back pain.[7] Studies have also shown that between 67% to 85% of centralizers displayed the directional preference for a spinal extension.[8] This preference may partially explain why the McKenzie method has become synonymous with spinal extension exercises. However, care must be taken to accurately diagnose the direction of pain, as one randomized controlled study has shown that giving the ‘wrong’ direction of exercises can actually lead to poorer outcomes.[9]

Other or Nonmechanical syndrome refers to any symptom that does not fit in with the other mechanical syndromes, but exhibit signs and symptoms of other known pathology; Some of these examples include spinal stenosis, sacroiliac disorders, hip disorders, zygapophyseal disorders, post-surgical complications, low back pain secondary to pregnancy, spondylolysis, and spondylolisthesis. 

Anatomy and Physiology

The intervertebral discs act as a spherical joint, permitting movement in flexion, extension, lateral bending, and rotation.[10] Internal disruption and displacement of the nucleus pulposus - annulus fibrosus complex will result in either back pain or referred pain along the nerve course, or both, depending on the degree of displacement and whether or not there is associated nerve root compression. The basis for extension based pain is most commonly the movement of the nucleus pulposus within the annulus fibrosus of the intervertebral disc.[7] Thereby, mechanical deformation of soft tissue around the spine will occur secondary to stress, such as improper posture. Thus, as a treatment for increased flexion, McKenzie prescribed extension exercises to restore or maintain normal lumbar lordosis.

Indications

McKenzie exercises are prescribed to patients who exhibit the centralization phenomenon of back pain. Centralization refers to the abortion of distal referred pain in a sequential fashion with the pain ultimately localizing at the midline of the body. Exercises are indicated based on directional preference, and their indication is the same direction of directional preference. For example, if a patient exhibits a directional preference for spinal extension (most common), the exercises performed will be in spinal extension.

Technique or Treatment

Physical therapists trained in the Mckenzie method will prescribe exercises in association with the centralization phenomenon mentioned above. Given that most people classify with a directional preference for spinal extension, this will be the direction of their prescribed exercises.

Examples of such spinal extension exercises include, but are not limited to:

1. Prone position lying flat (patient lies flat on their stomach)
2. Prone position propped on elbows (patient lies flat on their stomach and props themselves onto their elbows with the spine in extension)
3. Prone position propped on hands (patient lies flat on their stomach and props themselves onto their hands with elbows in full extension, with the spine in extension)
4. Standing lumbar extension (patient stands upright with feet shoulder-width apart, and puts hands on the lower back while extending the spine)

Similar exercises may be performed targeting spinal flexion, rotation, or lateral bending.

Clinical Significance

Multiple studies have identified a positive prognostic value of centralization, with pain that does not centralize correlating with a poor behavioral response.[6][11][12] Thus, the McKenzie method of assessment and classification of lower back pain has been shown to have demonstrated more reliability than any alternative method of examination.[13] Studies have shown that while this method may not be superior to other rehabilitation interventions for pain and disability reduction in patients with acute lower back pain, there is moderate to high-quality evidence supporting the superiority of the McKenzie method over other methods in reducing both pain and disability in patients with chronic lower back pain.[4][14] McKenzie exercises have also been demonstrated to work on the cervical spine, with one study showing significantly improved cervical posture of people with a forward head posture.[15]

Enhancing Healthcare Team Outcomes

While primary care physicians and nurse practitioners may prescribe physical therapy or a home exercise program for the treatment of back pain, the McKenzie method of Mechanical Diagnosis and therapy allows for the physical therapist to specifically target such back pain according to the classification obtained in their assessment. Although McKenzie exercises have become synonymous with spinal extension exercises, clinicians should be aware that the McKenzie method may involve exercises in any plane, depending on the patient's directional preference. This is very important because the goal of centralization depends on the directional preference of the individual. Although most patients favor spinal extension, there are, however, patients who favor spinal flexion instead. For these types of patients, the repetitive extension based exercises can possibly lead to peripheralization which is the worsening of distal referred pain from repetitive motion. In contrast to centralization, peripheralization does not carry a good prognosis and is to be avoided. It is thus vital for clinicians to form an accurate assessment of the directional preference rather than assuming a patient will favor extension and thereby proceeding with therapy based on that assumption. Overall, nurses and physicians should work in an interprofessional team with therapists to educate patients using these exercises to obtain the best outcomes. [Level V]