Mechanisms of Manual Therapy – How does it Work?
Our goal as physical therapists is to help people feel better, move better, and ultimately live better. One way that we achieve this is through manual therapy (AKA hands-on) treatments, including manipulations (faster, low-amplitude movements) and mobilizations (slower, low- to high-amplitude movements). If you have ever participated in physical therapy, chances are that your PT did some form of manual therapy to work on, or near, the parts of your body where your pain was. You likely walked out of that treatment feeling less pain, as that would have been the goal of the PT’s treatment. Did you ever wonder to yourself, “How did that work to help me feel better???”. You’re not alone.
This is a question that the PT profession as a whole has been working toward answering over many years through the undertaking of extensive research. Although there is no “one” answer for how manual therapy specifically works to reduce pain and improve overall function, the studies have shown that, rather, there are many moving parts that contribute to the effectiveness of manual therapy treatments. A model for this was created by Dr. Joel Bialosky, et. al, back in 2009 with the intent of guiding future studies and serving as a basis of the knowledge we have about how manual therapy works so far.1
I’d like to take this opportunity to break down the model above so that it makes more sense to anyone reading this, regardless of your background in health sciences.1
- When manual therapy (the “stimulus”) is applied to a certain part of your body (the “tissue”), the immediate effect is decreased spasm of the muscles in the area and increased motion.
- This stimulus being applied sets off a cascade of effects, starting with the “peripheral nervous system” (all of the nerves in your body besides those in your spinal cord and in your brain). An effect of this stimulation is that cells that help attack inflammation are sent to that area (“inflammatory mediators”).
- Then, the information is sent to the main nerve conduction track between your body and your brain (the “spinal cord”). From here, a whole host of proposed effects occurs, including improved muscle activity of the area that was worked on and decreased pain (“hypoalgesia”).
- After the information gets to the spinal cord, a feedback loop with the brain begins, which includes changes related to pain, involuntary nervous system (“autonomic”) responses such as changes in stress hormone levels, heart rate, and skin temperature, endorphin and opioid responses (the “feel-good” hormones), and psychological responses to the treatment including expectation and the placebo effect.
All of that boils down to the fact that, after a PT has performed a specific-to-you manual therapy treatment, you typically feel better! This model just demonstrates that there are a lot of factors that play into the why of you feeling better, and research in this subject continues to evolve so that we, as PTs, can better understand how our treatments help you feel better. If you have more questions about how manual therapy works to reduce your pain, make sure to come in and speak to a physical therapist to learn more and benefit from this treatment.
- Bialosky JE, Bishop MD, et al. The mechanisms of manual therapy in the treatment of musculoskeletal pain: A comprehensive model. Man Ther. 2009;14:531-538.