Mechanical Diagnosis & Therapy
What Is the McKenzie Method of Mechanical Diagnosis and Therapy?
Developed by New Zealand physiotherapist Robin McKenzie, the McKenzie Method of Mechanical Diagnosis and Therapy (MDT) is a structured approach to evaluating musculoskeletal pain through movement and symptom response. Instead of beginning with a predetermined exercise, MDT begins by testing what meaningfully changes the problem.
More than “McKenzie exercises”
MDT is not a list of exercises.
Online, the McKenzie Method is often reduced to a press-up or a handful of extension exercises. But an exercise is not the method. The clinical process comes first.
An MDT assessment establishes a baseline, tests repeated movements or sustained positions and then reassesses symptoms and movement. If one direction produces a meaningful and lasting improvement, that response helps guide the next step. If the response is unfavorable, or no useful pattern emerges, the strategy changes.
The goal is not to force every person into the same protocol. It is to identify whether the presentation demonstrates a reproducible mechanical pattern that can help guide management.
The exercise is not the starting point. The response is.
Reading the response
Three terms that explain how MDT works.
MDT looks for patterns across repeated testing. These terms describe some of the most clinically useful changes, not merely whether a movement feels easier for a few seconds.
01
Directional preference
A direction of movement or loading associated with meaningful, lasting improvement in symptoms, movement or function. The useful direction is identified through testing rather than assumed in advance.
02
Centralization
Centralization describes a change in which symptoms that were felt farther from the spine progressively move closer to it. For example, leg symptoms may move toward the low back, or arm symptoms toward the neck. The symptomatic area may become smaller even if some central discomfort remains temporarily.
03
Peripheralization
A response in which symptoms progressively move farther away from the spine during testing. For example, symptoms may extend farther down the leg or arm. In the context of an MDT assessment, a consistent peripheralizing response can indicate that the current movement direction or loading strategy is unfavorable.
Centralization is about where the symptoms go.
Improvement is not always captured by a single pain score. A change in symptom location can provide important information about how the presentation is responding.
Symptom response is only one part of an appropriate assessment. Worsening symptoms, progressive neurological changes or other warning signs require qualified clinical evaluation.
The assessment process
What does an MDT assessment actually do?
An MDT assessment begins by establishing a baseline: where the symptoms are, how they behave, what movements are limited and what activities make the problem better or worse.
Repeated movements or sustained positions are then tested and the baseline is reassessed. Did symptoms move? Did motion improve? Did one direction consistently help while another made things worse?
The feedback loop
Establish a baseline → Test → Reassess → AdaptThose responses help determine whether a useful mechanical pattern exists and what to try next. If the pattern is unclear or unfavorable, the answer is not simply to keep doing more of the same exercise.
Progressive weakness or neurological change, severe or rapidly worsening symptoms, major trauma, systemic illness, new bowel or bladder dysfunction, numbness in the saddle or groin region, or other concerning features warrant clinical or medical evaluation rather than continued self-testing.