What is a “Knot” and How Does Massage Therapy Work?
A Comprehensive Guide to the Science of Muscle Tension
During massage sessions with clients I often receive two specific questions that stem from their curiosity of how their body works and what changes are happening during the session: “What is a knot, anyway? And how does massage work?”
We have all personally experienced what a knot in a muscle feels like, and many have received massage therapy at some point, yet few truly understand the complexity of what is actually occurring beneath the surface.
The good news is, once you understand what is happening, you can begin to be intentional about making changes to improve or prevent tension — not merely through bodywork, but through your own daily habits and lifestyle.
So what exactly is a knot in the muscle, really?
Let’s explore.
Firstly, tension begins as a pattern in the nervous system. These patterns are generally manifestations of:
Stress
Chronic Postural Habits
Protective Guarding After Injury
Sensitized Tissue After Training
Emotional Holding Patterns
Sedentary Lifestyle
Overuse
Unideal Positioning During Sleep
Illness
Chronic Shallow Breathing
Etcetera
These things can all increase baseline muscle tone. If that output stays elevated for a long enough period of time, certain muscles remain subtly contracted. Eventually, your brain adapts these patterns in your body to become efficient and automatic.
Simply stated, once your nervous system develops a pattern, it teaches your body to adapt around it.
How does this work?
Sustained low-level muscle contraction can reduce local circulation. The effect is that this allows metabolic byproducts to accumulate while oxygen and nutrients have more difficulty entering in. Metabolic byproducts are substances produced during cellular metabolism (catabolism or anabolism) that are unusable by the body and often toxic if allowed to accumulate. Key waste products include carbon dioxide, nitrogenous compounds (urea and ammonia), lactic acid, creatinine and excess water. These substances are continuously removed by organs like the kidneys, lungs and skin to prevent toxicity.
Nociceptors (pain sensors) become more sensitive.
Collagen fibers remodel along lines of chronic physical stress.
The extracellular matrix is a complex, non-cellular 3-D network of proteins and carbohydrates (collagen, elastin, proteoglycans) surrounding cells in tissues. With muscular tension, substances in this network (specifically hyaluronan) can become more viscous; reducing smooth fascial glide. Hyaluronan or hyaluronic acid is a natural, high-molecular-mass polysaccharide found throughout the body's connective, epithelial, and neural tissues.
So again, what you feel as a “knot” is likely a combination of sustained low-level contraction and altered local tissue chemistry that reduces fascial glide, heightens sensory sensitivity and increases neural drive. Neural drive is the signal sent from the nervous system to communicate to the muscles to determine force and speed of contraction.
If there is an injury involved, there is increased complexity. Scar tissue forms as a part of normal healing. But if movement and load aren’t gradually reintroduced, protective bracing can persist, long after the tissue has healed — reinforcing stiffness and altered motor patterns. This can lead to reduced range of motion and painful movement. In bodywork, this can feel like “crunchiness” and what we call adhesions — meaning the tissues feel like they’ve adhered together. This is precisely why physical therapists will reintroduce movement and light load on post surgical patients almost immediately; often within 24 to 48 hours after surgery. When addressing this during a bodywork session, massage therapists actively work to break up and disrupt the scar tissue in order to stimulate a better healing trajectory and increase fluidity of the extracellular matrix.
Outside of bodywork, this means striving to mindfully address the nervous system before it manifests as tension in the tissues. One way to do this is by utilizing strategies to regulate stress that will work for you. Develop a habit to take notice of your body. Become aware of when you contract and where. Stay mindful of posture. Make an effort to vary your bodily movement throughout the day.
And how does massage therapy work?
When it comes to treating these issues with bodywork, we understand that if tension is rooted in the nervous system, it follows that we must learn to work with it and not against it to provide lasting results. Tension in the body and your mind isn’t released through force, but through safety. Establishing trust is key. After that we can be intentional to apply the appropriate amount of pressure and flow with the ideal pace for your specific needs. Enough to create meaningful input for the nervous system, muscle and fascia — but not so intense that it triggers more guarding or inflammation, which consequently can cause you more harm than good.
When the pressure is so intense that the body starts bracing, holding breath or mentally checking out, their system is clearly in defense mode; not release mode. The result, of course, is no lasting benefit. Inadvertently inducing a stress response will likely have the opposite intended effect. That’s why the goal shouldn’t be maximum massage pressure, but to introduce touch and pressure slowly and gradually. This means that the nervous system has time to register it as safe, which allows deeper layers of fascia and muscle to release instead of resisting or “pushing back”.
Collaborating with your massage therapist to optimize your session for meaningful, lasting results means your therapist will communicate these concepts. This will help foster an environment of safety and for your tension (and nervous system) to naturally let go and have lasting results. It’s imperative for you to feel empowered and encouraged to interject your feedback to shape the session to best serve you so your “knots” can melt away.
In reality, a “knot” isn’t merely a random, hardened bit of muscle. It’s a systemic combination of nervous system and tissue adaptations that are inextricably linked. Massage therapy works not only by what we actively do to the soft tissue, but also by encouraging your mind and body to release the tension.