Mechanical Diagnosis and Therapy

What is mechanical diagnosis and therapy?

It’s another name for the McKenzie method and approach to physical therapy.The McKenzie Method® of Mechanical Diagnosis and Therapy® (MDT) is an internationally acclaimed method of assessment and treatment for spinal and extremity pain developed by New Zealand Physiotherapist Robin McKenzie. It doesn’t just rely on treating the symptoms that patients feel but instead gets to the root cause and addresses the source.

Robin McKenzie released his first book in 1981, starting to train physical therapists throughout the world in this method.  This approach to therapy doesn’t rely on the traditional moist heat, ultrasound, and/or electrical stimulation approach. Instead, the McKenzie Method uses specific movements in a repetitive way to identify the direction of movement that the patients prefer/need to reduce symptoms. We call this movement the “directional preference (DP)” and is a key point to the successful treatment using this method.


So what does this mean for our patients?

When you take your tire into the shop because it’s flat, they don’t just fill it back up with air! (or they shouldn’t) They look for the reason why the air is gone in the first place. Next, they do something to fix that issue before filling the tire back up with air.


What if I have back and leg pain?

Mechanical diagnosis and therapy first identifies what tissue is causing the pain radiating into the leg – perhaps a disc placing pressure on a nerve root- then finds a movement that reduces that pressure on that nerve. As a result, the pain in the leg  will reduces, allowing the therapist to introduce back and leg strengthening exercises to ensure less risk for re-injury.


The McKenzie method has specific exercises and hands-on techniques aimed at reducing pain both in the back and extremities, attempting to centralize pain using specific movements or directional preference. This “centralization” phenomenon is specific to therapists utilizing the McKenzie method. The presence of centralization has become such an important factor in dictating what the prognosis will be. It has extensively demonstrated that when the therapist is able to help the patient achieve a centralization of symptoms, the outcome is always better.  According to research, a knowledgeable, experienced McKenzie physical therapist achieves centralization of symptoms for the patient 40-75% of the time.

Research on the McKenzie method clearly supports its use as an effective conservative approach to the treatment of spinal and extremities problems prior to more invasive treatments, such as injections and surgery.  When compared with just strengthening alone, patients improve earlier in their rehab. When compared to non-specific exercises  alone (not using the patient’s directional preference), the outcomes with the McKenzie approach are significantly better in pain reduction and return to normal activities.

At East Tennessee Spine and Sport, each office has a physical therapist certified in mechanical diagnosis and therapy (MDT) from the McKenzie Institute international. Our Farragut office meets the highest standards with the McKenzie Institute, and is the only certified McKenzie clinic in Knoxville and the state of Tennessee. This ensures that our patients will receive the top level of care for their pain issue.


So how does mechanical diagnosis and therapy work?

By asking a series of specific and in-depth questions, the therapist is able to learn much more about the factors that is causing the problem, and is able to begin to identify potential solutions. Through spending the time sitting with and interviewing, and truly listening to the patient’s answers, particular patterns begin to appear that help the therapist know the extent of testing that needs to be performed.

Next through a series of standard musculoskeletal tests and also the addition of specific repeated movement testing procedures the patient’s preference to movement (called the directional preference) is identified and then turned immediately into a dosed specific exercise program for home.

This specific exercise direction is then supplemented with hands-on manual therapy techniques to achieve full reduction in pain and restoration in movement.

With the McKenzie method, therapy will be split into three phases. The first phase is controlling the pain and identifying the specific exercises that need to be performed. Then. the addition of strength or reactivating exercises to ensure that muscles maintain this pain reduction begins.  The final phase is ensuring that the patient is returning back to their normal functional activities without pain or limitation.

This is expected to be achieved in 6 to 12 visits. The ultimate aim is to create a program for the patient to continue with independently in order to maintain the improvements and not require continued care from the practitioner for this episode.


For more information about the McKenzie method visit or contact one of our offices to speak directly with the therapist or to schedule a free screening to see if this approach may help you or indeed to schedule a full evaluation and begin treatment. In the state of Tennessee, you do not need a physician’s referral to begin a course of therapy, so please contact us directly to ensure coverage from your insurance.