There is a growing body of research starting to catch up with the practices of manual therapy and discover some of the reasons it may help.
For anyone who’s ever faced a lingering injury or the everyday stiffness that comes with modern life, the promise of manual tissue work—massage, myofascial release, and other hands-on therapies—may sound like yet another wellness trend.
But a growing body of research suggests there’s a solid scientific foundation for these practices, particularly in how they influence a crucial but often overlooked component of the body: the extracellular matrix (ECM).
At the heart of this discussion is hyaluronan, or hyaluronic acid (HA), a naturally occurring molecule within the ECM that plays a key role in keeping our tissues pliable, hydrated, and mobile.
Let’s dig into how manual tissue work to improve pliability interacts with HA and collagen to improve mobility, reduce pain, and support recovery—and why the impact of these therapies is far from superficial.
The Role of Hyaluronan and Collagen in Movement
The ECM—a network of fibers and gel-like substances surrounding our cells—is critical to the structure and function of tissues like fascia, muscle, and tendons. Two of its most important components are HA and collagen.
HA, a high-molecular-weight glycosaminoglycan, provides viscosity and hydration, allowing layers of tissue to glide smoothly over one another during movement. Collagen, meanwhile, offers strength and support, but excessive buildup or disorganization of collagen fibers can stiffen tissues, leading to pain and limited mobility.
When tissues are healthy, HA ensures optimal lubrication and pliability. But in the aftermath of an injury, immobilization, or chronic inflammation, the balance between HA and collagen can shift. HA levels drop, viscosity decreases, and collagen accumulates—changes that compromise the sliding mechanics of tissues and contribute to stiffness.
Non-Newtonian Fluid Dynamics and Viscosity
HA’s unique behavior as a non-Newtonian fluid is central to its role in tissue function. Unlike water, which has a constant viscosity regardless of stress, non-Newtonian fluids like HA change viscosity in response to applied forces.
A relatable example is cornstarch mixed with water (Oobleck): under slow movement, it flows smoothly, but under sudden force, it stiffens. See the video below for some pretty dramatic examples of this!
Similarly, HA’s viscosity adjusts dynamically, allowing it to lubricate tissues effectively under varying mechanical loads. Fast loading makes it stiffer, slow loading allows it to flow. This property is essential for facilitating smooth tissue glide and adapting to the demands of movement.
The Evidence: What Happens to Tissue After Injury?
Recent studies provide a clear picture of these changes. For instance, research on rats with sciatic nerve injuries showed significant alterations in the thoracolumbar fascia (TLF) and lower limb muscles.
HA concentrations in the injured side’s TLF decreased by over 60%, while collagen levels more than doubled. Even the contralateral, uninjured side experienced reduced HA levels, highlighting the systemic effects of injury on the ECM.
These changes correlated with decreased tissue mobility and increased stiffness—the hallmark symptoms of impaired ECM function.
This study is part of a broader body of research demonstrating that HA’s molecular weight and concentration are critical for maintaining tissue flexibility and hydration. When these properties are disrupted, tissues lose their capacity to glide, and adhesions between layers can form. This makes movement inefficient and, in some cases, painful.
How Manual Tissue Work Helps Restore Balance
Manual tissue work provides a mechanical stimulus that addresses these ECM imbalances in several ways:
1. Stimulating HA Production
The application of pressure and shear forces during manual therapy promotes the production of HA by specialized cells within the fascia, known as fasciacytes. These cells respond to mechanical loads by increasing HA synthesis, enhancing hydration and lubrication in the ECM. This process not only improves tissue glide but also helps prevent the stiffening associated with HA depletion.
2. Breaking Down Adhesions
After an injury, collagen fibers can bind excessively between tissue layers, forming adhesions that restrict movement. Manual therapy applies targeted force to disrupt these adhesions, encouraging ECM reorganization and restoring the tissue’s natural architecture.
3. Applying Slower Shear Forces
Unlike techniques that rely on deep pressure alone, myofascial therapy introduces slower, controlled shear forces to engage the unique non-Newtonian properties of HA. These deliberate movements reduce viscosity in areas of densification and enhance tissue pliability. This approach ensures that changes occur at the appropriate depth and within the ECM’s structural layers, optimizing tissue glide and function.
Beyond Injury: Applications for Everyday Athletes
While the benefits of manual tissue work are evident in post-injury recovery, they’re just as relevant for preventing stiffness and maintaining mobility in healthy individuals.
Modern lifestyles—characterized by prolonged sitting and repetitive motion—can lead to areas of tissue densification and ECM dysfunction.
Manual therapy acts as a preventative measure, maintaining optimal HA levels and collagen organization to support efficient movement.
For athletes, these therapies provide an edge by enhancing recovery and reducing the risk of overuse injuries. By keeping the ECM hydrated and pliable, manual tissue work ensures that fascial layers can adapt to the demands of intense training and competition.
A Holistic Approach to Recovery
It’s worth noting that manual tissue work to enhance pliability is most effective when integrated into a broader recovery strategy.
Movement itself—through exercise and stretching—also imposes fluid shear stress on the ECM, promoting HA synthesis and tissue health.
Targeted manual tissue therapy can ensure that specific tissue structures and fascial chains, which might not be adequately stimulated by general movement, receive the attention they need. Combining manual therapy with active recovery practices creates a synergistic effect, addressing both the mechanical and physiological aspects of ECM function.
Manual Tissue Work for Pliability: Supported by Science
Manual tissue work is more than a feel-good intervention; it’s a scientifically supported approach to improving tissue health and mobility.
By influencing the properties of HA and collagen within the ECM, these therapies help restore balance to injured tissues and maintain pliability in healthy ones. For anyone looking to move better—whether recovering from an injury or optimizing performance—manual tissue work offers a practical, evidence-based solution.
REFERENCES
- Zhao X, Fede C, Petrelli L, Pirri C, Stocco E, Fan C, Porzionato A, Tiengo C, De Caro R, Masiero S, Stecco C. The Impact of Sciatic Nerve Injury on Extracellular Matrix of Lower Limb Muscle and Thoracolumbar Fascia: An Observational Study. Int J Mol Sci. 2024 Aug 16;25(16):8945.
- Gouverneur M, Spaan JA, Pannekoek H, Fontijn RD, Vink H. Fluid shear stress stimulates incorporation of hyaluronan into endothelial cell glycocalyx. Am J Physiol Heart Circ Physiol. 2006 Jan;290(1):H458-2.
- Pratt RL. Hyaluronan and the Fascial Frontier. Int J Mol Sci. 2021 Jun 25;22(13):6845.
- Cowman MK, Schmidt TA, Raghavan P, Stecco A. Viscoelastic Properties of Hyaluronan in Physiological Conditions. F1000Res. 2015 Aug 25;4:622.
