Mechanisms of Manual Therapy

One of the best things about being a physical therapist is the requirement to continually improve. 

To maintain our license we must accrue around 45 hours of continuing education every two years. 

Even though each course can eat up an entire weekend, it is a huge privilege to better our craft via incredible educators and lots of hands-on lab time. 

Recently, we completed a manual therapy course presented by Evidence in Motion called “Effortless Spinal Manipulation and Advanced Therapeutics.”

Dr. Pope providing manual physical therapy

Let’s Back up: What is Manual Physical Therapy?

There are a few different things we can do in a physical therapy appointment.

One of the most common things that we at Chain Effect focus on – certainly one of the most important starting points – is called “manual therapy” or “manual physical therapy.”

Manual therapy encompasses many highly skilled and specialized hands-on techniques. Examples include manual massage, dry needling, cupping, and joint, spine and soft tissue mobilizations and manipulation.

This is something that makes us different from other physical therapy clinics: We have the resources available to place a heavy emphasis on manual physical therapy in our sessions.

Spinal manipulation (one of the primary focuses of the recent course) falls into the manual therapy category, so the course was right on-brand.

One cool thing about the Evidence in Motion course is that it was a hybrid online/in person course, meaning we do the preliminary didactic theory and philosophy work before the weekend and then use the in-person time for extensive hands-on lab work.

We started with a review of “the why” behind why manual therapy works, because the evidence repeatedly proves it does work. We continued on with a review of the mechanisms that also included some great knowledge bombs we hadn’t considered.

So how does manual physical therapy work? In this blog post, we’re going to take a technical deep-dive into the 8 mechanisms of manual therapy.

Manual massage

The Hypoalgesic Mechanism of Manual Therapy

Hypoalgesia means a decreased sensitivity to painful stimuli.

Manual therapy has a hypoalgesic effect on the patient receiving treatment.

Our understanding of pain science is rapidly evolving, but using functional MRI (fMRI), we are now able to see changes in the brain as it responds to pain. These changes have been shown to occur during and after manual therapy is being performed.

One study showed that when performing a thoracic manipulation there was an immediate analgesic effect in patients with neck pain (1).

Peripheral nerves are nerves that are outside the brain and spinal cord. We have always known there to be two main types of peripheral nerves. These are:

  1. Efferent- Motor nerves which send instructions from the brain and spinal cord to control movement by contracting our muscles
  2. Afferent- Sensing nerves that relay information to the brain and spinal cord from the skin and other organs

Therefore, when changes in the brain occur during manual therapy, they send efferent (from brain to body) messages back to the pain area, resulting in a perceived decrease in pain.

This allows your body’s alarm to decrease, opening up the door for more effective treatment and exercise.

The Nervous system. Credit: magicmine - stock.adobe.com

Psychosocial

A psychosocial effect (or, simply put, the placebo effect) can have a large effect on how we perceive pain.

Now, when discussing placebo, people will often categorize it in a negative fashion as if it’s something that doesn’t work or it’s just your brain tricking you.

We would argue the contrary.

The human brain is the most powerful thing in this world and we have still not scratched the surface of what all it can do. We have all had those times where we feel like our minds are playing tricks on us when we are hungry, thirsty or tired.

An example we like to use to show the power of our minds is:

Imagine you are playing a round of golf and there is a pond right in front of you. What are you saying to yourself?: “Don’t hit it in the pond, Don’t hit it in the pond, Don’t hit it in the pond.”

What do you do?

That’s right, you hit it directly into the pond, because your focus was actually on the pond.

This metaphor can be applied to manual therapy as well.

Now imagine:

You have low back pain and you just talked to your friend who had the same low back pain. Your friend just received dry needling and all his pain went away.

The first thing you are going to do is find someone to perform dry needling.

Now you are coming into this treatment thinking and believing that dry needling is going to cure your pain.

It is that expectation and belief that the treatment is going to work.

Your focus is on it working.

Science shows that this positive expectation that a treatment is going to work actually can produce more positive effects than if you do not believe it will work.

This is how positive expectation can be a placebo in itself. But hey, it works!

Seeing the Placebo in Practice

Believe it or not, most patients come into each appointment with a belief that the treatment will work, which, as we discussed, is a placebo in itself.

Occasionally, a patient will come believing that physical therapy will not help their pain. This negative thinking actually can cause a detrimental effect called a nocebo.

The patient’s belief alone can have a huge effect on the session even before it starts.

Therapeutic Alliance During Manual Therapy

There has also been a lot of discussion on the topic of therapeutic alliance.

This is the working rapport and positive social connection between the therapist and the patient.

We have always been big believers in building a relationship and trust with our patients. We take the relationship and trust very seriously.

Someone is coming to us at a difficult time in their life and looking for help to solve their problems.

We take on the mentality that your knee pain is now our knee pain, and that we are going to go on this journey together.

That teamwork mentality can also play a strong role in recovery.

Mechanical

The mechanical effects are the most popularly-discussed reasons why manual therapy is helpful: The actual movement of your body.

Our manual therapy techniques have been developed and optimized over years of practice and study.

We can manipulate the stress and tension we place upon you just by the position of your body, the physical therapist’s hand placement, and force vector.

By understanding human anatomy and kinesiology (how the body moves), we can pinpoint the focus of our treatment.

A famous 1992 study that is still relevant and cited today showed the stress placed through the lumbar spine can be changed by simple positioning. It showed that when standing straight up, 100% of the body’s weight above the hips is placed on the lumbar spine. When seated, 140% of the weight is placed on the lumbar spine. When lying on your back with your knees bent, weight on your lumbar back decreased to 25% (3).

This could be an explanation of why so many people have increased low back pain with prolonged sitting.

It also gives us an insight of the best position to place our patients in during treatment.

Depending on the patient’s irritability, we can change that position over time to further load the spine and progress to more functional, standing activity.

Autonomic

An autonomic response ties into your body’s uncontrolled response to a stimulus.

We have two reactions in our autonomic nervous system:

  1. The sympathetic response, also known as the “flight or fight ” response, in which there is an increase in heart rate, blood flow, and focus.
  2. The other is the parasympathetic response, which is our “rest and digest” response. This is when we are sleeping, relaxed, or in a deep meditative state.

Studies have shown an increase in sympathetic response in the extremities following a thoracic spine mobilization (4).

This correlates with several other studies that have shown increased blood flow following joint manipulation.

This is important because with increased blood flow comes increased healing.

Our body does an amazing job of healing itself but sometimes it needs a nudge in that direction. By utilizing manual therapy concepts (including cupping and dry needling), we can assist in stimulating the release of healing proteins and increased blood flow which will get you on the path to healing.

Neuromuscular Mechanism of Manual Therapy

You can think of the neuromuscular mechanism as the “Control, Alt, Delete” reset of the human body.

Pain is a natural defense mechanism that your body utilizes to protect a potential injured area. In efforts to protect the area, pain signals can inhibit muscle strength and function. But oftentimes, healing is achieved when you access your strength and use it in a new way. Since your body is in this protection mode, manual therapy is a way to “reset” and access our strength in order to heal.

Mobilizations and manipulations have shown to have an immediate impact on muscle strength (5). This tells me that if you come into the clinic with shoulder pain, I can utilize neck manipulations to increase your shoulder strength. This is a huge discovery and can allow improvements without directly touching the shoulder.

That’s powerful stuff!

shoulder manual therapy

Chemical

The chemical effect of manual physical therapy is a new and very exciting discussion.

There have been several studies recently released discussing the chemical effect.

These studies demonstrate that inflammatory chemicals are closely related to radiculopathy (pain down your arm or leg). What they have found is increased chemical activity and inflammatory response in the dorsal root (6). This is the area of your spine in which the nerve exits the canal to provide sensation and muscular function. It is relatively common for patients to enter the clinic with a disc herniation that was diagnosed on a MRI. They are coming in with pain down their leg. This can be a scary diagnosis; However, many strategies have been developed in physical therapy to centralize that pain and restore function.

It’s important to note that most often, patients return to normal function and no longer have pain down their leg; However, if they did another MRI, it would still show a disc herniation. So why is it that an MRI can show a herniation but you do not currently have any pain? Well the answer is pretty simple, there is no longer inflammation or compression on that nerve root.

When we are born we have an instinctual internal map of our bodies. This information is stored in our primary somatosensory cortex. This mapping is more commonly known as the homunculus.

As we develop, we begin to sharpen the lines between the different parts of our body.

We develop more fine motor skills with our hands, feet, and mouth. In turn, the homunculus becomes larger and more defined for those fine motor skills.

The same can be said when we stop movement in an area or lose strength: those lines begin to blur, and the definition of the homunculus fades. We lose coordination and sensation of where that body is in space. A blurring of those lines have shown to put the body on high alert. The threat level goes up and the body becomes more sensitive to pain.

This transitions us into the discussion of neuroplasticity.

Neuroplasticity

Neuroplasticity is a general term referring to the ability of neurons to alter their structure and function in response to internal or external stimuli.

Studies have shown that as pain increases, we have less perception of different areas of our bodies.

Simple exercises can be implemented to help with this remapping.

A study in 2015 showed that there can be an improvement in low back pain just by helping a patient better identify their body (7).

During the study, they had patients lying on their stomach and the therapist would touch different parts of their back. If the patient got the position correct, they would move on, if they did not they would correct them and try again. Once the patient was able to better identify the exact location of the touching on their back, they retested their range of motion and strength. There was immediate improvement in forward flexion as well as decrease in pain.

All that was performed was a simple remapping and sharpening lines in the cortex which helped turn down that alarm system.

Socioeconomics

Believe it or not, socioeconomics has an effect on why manual physical therapy is effective.

We all have different stresses in life, whether it is financial, social or participating in a hobby that you love.

There are many studies out there that show whether you do just manual therapy or just therapeutic exercise during physical therapy appointments, that you will be at the same place in one year. However, the journey is much different. Patients who received manual therapy vs. those who did not required fewer physical therapy visits, leading to decreased cost and time spent in treatment (2).

This means returning to running sooner or not missing your child’s baseball game because of an appointment.

All because manual therapy was included in your treatment plan.

Summary:

We’ve previously discussed how dry needling is different than acupuncture and cupping for plantar fasciitis.

We’re glad to now bring you more of the science behind these techniques and other manual therapy techniques.

This course gave us a better understanding of why manual therapy helps our patients and also some new hands-on techniques.

This course in particular was focused on treatment of spinal conditions with use of manipulation. It consisted of 2 days of in-person training for treatment of the cervical, thoracic, and lumbar spine.

The best parts about a course like this are:

  1. It encompasses clinicians from all around the country
  2. You can share experiences about patients and swap ideas
  3. You get to perform treatment on different body types and receive immediate feedback

This hands on work is what really sharpens those new tools.

As we said before, if we are not continuing to learn new techniques and keep an open mind to new data, we are doing our patients a disservice.

As a PT, we must be a student for life!

We look forward to sharing our new skills with you as we stay up to date on the newest, cutting edge treatment for your pain.

Authors

Dr. Taylor Pope owner of Chain Effect and one of the Doctors of Physical Therapy at Chain Effect
Dr. Jason McLaughlin headshot

Co-Authored by:
Taylor Pope, DPT, FDNP, Owner and Jason McLaughlin, DPT, CSCS, TDN.

Taylor Pope and Jason McLaughlin are experienced physical therapists, Certified Dry Needling Practitioners, and movement experts.