At Camp4’s sports injury clinic in Taylorsville UT, we recognize the importance that myofascial tissues have in controlling your overall pain and function. We utilize our hands, needles, and tools to help reform injured tissue and to try and create less tension to promote symmetric agonist/antagonist muscle contractions, side to side, and front to back. Manual therapies directed at the soft tissues have been used for as long as we have record and provide good short term relief of pain and tension for many musculoskeletal conditions. There are many types of soft tissue therapies done by hand or with a tool such as myofascial release, positional release, pin and stretch, PIR, ART, and graston to name a few which all purport to provide a different effect on the soft tissues, however this is not well supported in the literature and cannot be explained by the mechanical properties of the soft tissues alone. Instead, it is far more likely at this point that all of these therapies provide the same effect on the soft tissues, the autonomic nervous system, the microvascular system, and most importantly patient perception. The most well studied and supported of these therapies for long-term tensile release, pain inhibition, and blood flow regulation is acupuncture dry-needling. Really it is a matter of choosing the right tool for the right patient. For those who don’t like needles, we might use our hands, for large body areas we might use a tool etc. It is no surprise to our patients that these therapies make them feel better but as physicians it our responsibility to understand the mechanisms responsible so as to best select the treatment right for you. We focus on this page to educate you about what the latest research says about therapies aimed at the soft tissues. If you already know the benefits of these therapies feel free to contact the sports injury clinic Taylorsville UT at anytime to schedule your appointment today. For those interested in getting a deeper understanding continue reading.
The relative comparative effectiveness of different methods and modalities, applied in different ways, over varying time-spans, remain largely un-evidenced from a clinical perspective. These treatments require more complex clinical research, on large enough numbers of participants to ensure that effects of individuality, including emotional factors, are accounted for in the results.
This quote is from a systematic review on soft tissue manual therapies published in 2010 and highlights the need for more rigorous research to differentiate the therapeutic effects of different soft tissue therapies. In order for you to better understand and analyze these therapies, we need to introduce you to the composition of “fascia” first, then we will discuss the proposed mechanisms of action currently accepted, and finish with an analysis of older theories and that research.
The term “myofascia“, as discussed below consists of the muscular (contractile) tissue and the collagen based meshwork that connects (the white stuff of your steak) and binds all tissues together. Fascia encapsulates all muscle fibers (endomysium), muscle bundles (perimysium), and whole muscle groups (epimysium), and twists upon itself at the end of muscles and becomes the tendinous attachments to the bone periosteum, and also to other muscle groups.
That final point is very important for this discussion, fascial connections to other muscle groups means that fascia has the capacity to affect muscles across joints and even on the opposite side of an extremity. It must be noted that fascia is not restricted to the muscular tissue, but also responsible for the shape and position of all your organs, peripheral nerves, and is responsible for holding your body together in its present form. Fascial tissues are the wires that hold up your ships mast and create both tension and compression on your body in all three-dimensions. This is the concept of tensegrity, and is at the forefront of research for manual therapists. All the way down to the cellular level your body is held together by this three-dimensional framework.
The 3D orientation of fascia is a very important concept to understand. For example the fascial tissues of the leg do not simply run parallel to the muscle fibers and bones they enclose but they also run perpendicular connecting layers of muscles to the the skin and also the bone. This is important because compression at one location creates tension at another distant location, all the way down to the cellular level.
Now you have and introduction we can discuss the composition of fascia!
The extra cellular material, or matrix (non cellular tissues) of fascia are composed primarily of collagen, elastin, and reticulin, with the majority of that substance being collagen. The collagen is formed in a triple helix and connected to other collagen fibers by glycosaminoglycans molecules which act as the glue to this substance. Elastin and reticulin function as the binding between adjacent collagen layers.
Glycosaminoglycans have colloidal properties, that means when water is present they are in a more liquid state that promotes tissue gliding, when water is absent they become less liquid and stick together.
The water in the extracellular matrix is responsible for mixing with the hyaluronic acid to make the materials necessary for the ECM. Two types of water are recognized at the microscopic level, bound water which is the healthier component of water responsible for tissue movement and hydration, and bulk water which is in the form of a liquid crystal and is present in states of inflammation, edema, and free radical formation. Proper movement has been demonstrated to replace bulk water with bound water and is very important in fascial health.
Water is 2/3 of the volume of the extra cellular matrix and is currently thought to be the most important component in fascial health.
The cellular component of fascial tissues consist of fibroblasts and mast cells. These cells are primarily responsible for the construction of the collagen fibers and the glycosaminoglycan molecules. The fibroblast in particular is under much investigation and has been demonstrated to synthesize, organize, and remodel collagen, depending on the tension between the cell and the extracellular matrix. With low amounts of tension from outside the cell, the fibroblast is in a resting state with low synthesis of collagen matrix. When placed in a high tension matrix the fibroblasts increase their collagen synthesis and cell proliferation. The cells themselves actually appear quite different in these two states. Each fibroblast can remodel nearby collagen matrix, and this local remodeling can spread throughout the matrix to result in large scale matrix contractions.By exerting traction on the matrix, the fibroblast can either cause motion of the collagen or movement of the fibroblast through the matrix, and this is very important in tissue healing after microtrauma to collagen molecules.
Another important thing for manual therapy practitioners to note is the orientation of the fibers of the collagen network at different locations. In the superficial and deep tissues, the collagen is in a criss-crossed pattern at approximately 45 degree angles as you move from the trunk to the extremities. It is helpful to think of the superficial fascial tissues as equivalent to a females stocking, or fascial body suit that is worn and covers the entire body. Once the fascia continues around each muscle fiber, bundle, and muscle group it then then converges to form the tendons and ligaments where the collagen fibers lie more parallel in orientation to one another. This changes the particular therapy we use depending on the location of a patients complaint, and often times it is in a distant location to the site of pain.
Some other important molecule types that we need to mention are heparin, fibronectin, and hyaluronan which are primarily responsible to accommodate change and provide the substrate for other cells such as nerves and epithelial cells. Hyaluronan is of particular interest in fascial research given it’s ability to further allow tissue gliding mechanisms.
With trauma to muscle, the overlying fascia no longer produces the sliding layer of hyaluronan. Restoring this natural sliding mechanism is the next focus of the manual therapist. Hyaluronan and water both need to be present for tissue sliding to occur.
Now that you understand fascia on the cellular level, lets talk about the relationship fascia has with the nervous system.
The fascia is intimately connected to the central and autonomic nervous systems through the free nerve endings between these fascial layers. In the recent literature, it is discussed how the myofascial tissues are the largest sensory organ of the body due to the large quantity of interstitial (type III and IV) mechanoreceptors. If you recall from the manipulation and acupuncture pages, mechanoreceptors are the nerve endings that inhibit pain and detect joint and body positions, which are both necessary for proper movement and overall function. Also it has been recently demonstrated that pain receptive free nerve endings also reside within these tissues making the myofascia a primary source of inflammatory and mechanical pain.
Now it is important to make note of the importance that fascia plays in human biomechanics.
Fascia is responsible for directional force transmission. You cannot contract muscles without moving fascia, and you cannot move fascia in only one direction and in one plane. For example, contracting your bicep muscle certainly pulls on the biceps tendon but also affects the fascia of the triceps muscle.
Anatomist Luigi Stecco has demosntrated that fascial planes converge at certain points on cadaver specimen’s. When compression is placed at these locations, tensile strain is placed on fascial tissues in multiple muscle groups, even on opposite sides of the same limb at distant locations.
Fascia modulates and re-directs the pressures produced by muscle contractions. Maximal force transmission can be dissipated to additional muscular units by muscle spindle activation through fascial tissue connection.
Fascia assists in movement endurance and in the containment of potentially damaging forces. Fascial tissues are elastic and have the capacity to generate enough recoil. An example of this is that in normal human walking the primary force responsible for the toe off phase is the elastic recoil of the achilles tendon, not contraction of the triceps surae muscles.
Fascia assists in maximizing power and saving energy by allowing slow twitch muscle fibers to relax while body postures are maintained against gravity. This requires fascial tensile symmetry within the body, although a very challenging thing to do, this is what manual therapies are out to accomplish.
Now it is time to discuss the current accepted theories on how these therapies help our patients. These ideas are changing rapidly and are based on the 3rd international fascial congress which was held in Vancouver in 2012. Updates to this will be in the blog section of the site as new research is published.
Most of these present ideas have come from applying the concept of fluid dynamics, which can predict how practitioners affect the soft tissues of the body. It is important to note that factors responsible for a change in the status of these tissues are previous injuries, varying hormone levels, nutritional status, tissue hydration, and temperature. By now you know that fascial hydration appears to affect mobility and movement between layers, shock absorption/energy distribution, and overall nutritional status. Remember also, this can be done by hand, with a tool, and most effectively acupuncture needles.
Fascial stimulation has been demonstrated to trigger the autonomic nervous system to change the local pressure in fascial arterioles and capillaries. This is a localized change in the blood pressure the the vessels traveling between fascial layers.
Strong fascial stimulation has demonstrated to influence plasma extravasation, that is the extrusion of plasma from blood vessels into the interstitial fluid matrix. This causes an increase in tissue hydration which is good for healing injured tissue and the rebuilding of collagen.
Fascial stimulation has been shown to change local extracellular matrix viscosity and potentially a change in the ground substance regulation. This is a complex mechanism and not well understood to date.
Fascial stimulation has shown increases in vagal tone (parasympathetic nervous system tone) leading to increased neuromuscular, emotional, cortical, and endocrine changes associated with deep and healthy relaxation. This is the affect of yoga type therapies on the soft tissues and the practitioners.
There continues to be a growing body of biological mechanisms which explain manual therapies affect on fascial tissues, however there is a lack of randomized controlled trials to support which symptoms will be affected by these therapies. There is a substantial body of anecdotal evidence however it remains relatively unclear exactly which problems, experienced by which sub-populations, will respond most readily to particular therapeutic approaches.
If this all sounded very complicated and unintelligible to you don’t be scared, it is very complicated and most of these theories have come out recently and are not well understood. The purpose of us making note of these theories is to highlight the importance of the central nervous system in the effects of manual therapies in general. The central nervous system, more specifically the descending inhibitory system, is the most powerful pain inhibiting mechanism available to patients. If you remember from the manipulative therapy page, it is 60x more powerful than pain medication.
Now you have some understanding of modern theories lets bust some old myths about soft tissue therapies, both active and passive. We will now turn our attention to discussing the properties of tissue extensibility (stretching) and adaptability to passive and active loading. First we need to introduce you to some biomechanics terminology to better help you understand this discussion and make and informed decision. Don’t be intimidated by the terms, we are going to make it very understandable.
Stress is defined as the measure of load (or energy) in an object that is independent of the amount of material.
Strain is defined as the stretch or displacement that a material undergoes, and true strain is the change in length divided by the original length.
The stress-strain diagram is a curved graph unique to each material, in this case the myofascial tissues, and is found by recording the amount of strain at distinct intervals of tensile or compressive loading (stress). Young’s Modulus is the slope of that curve and is used to measure of elasticity or stiffness of that particular material. Two important points on that graph are the toe region and a the yield point. In the toe region up to the yield point (the elastic phase), tissues return back to their original resting length once the load is removed. Once tissue strain has passed the yield point, tissues enter the plastic phase of the graph where they become permanently deformed and no longer return to their resting length. This is where micro and macrofailure of ligaments, tendons, and myofascial tissues occur.
Next we will talk about some terminology in reference to loading rates.
Deformation is the ability of a material to change shape as it is loaded, and the stiffer the material the less deformation it undergoes.
Viscoelasticity is the ability of a material to posses elastic and viscous properties. Solids which have a time-dependent mechanical behavior, which is fluid-like, are viscoelastic. All tissues of the human body demonstrate viscoelastic properties, especially important when talking about myofascial tissues.
Creep is the continued deformation of a tissue under fixed load where the amount of strain is measured as a function of time.
Stress relaxation is the reduction of stress in a material over time as the material is subjected to constant deformation. This is where a fixed displacement is sustained and stress decreases with time. This is commonly what patients and practitioners assume is tissue extensibility, or lengthening.
Two important take-aways from the biomechanics lesson.
Rapidly applied stress = increased tissue strain, slowly applied stress = decreased tissue strain
Now you know some terminology, lets discuss myofascial extensibility in more detail.
It has been thought in the past that we had the capacity to elongate myofasical tissues through passive manual therapies and stretching protocols. This has come under much consideration in the last couple of decades due to some very good research analyzing the methodologies employed during historic studies used to detect this property. A few important things to note:
The first concern was the varied utilization of the term “muscle extensibility” in different literature reports. Throughout the rehabilitation literature regarding the effects of stretching, confusion arises due to inconsistent use of the terminology among studies. It is important to note that muscular length is multidimensional and when more than one dimension is included in muscle length assessment, important biomechanical properties of the muscle can be determined.
These additional dimensions include tension, cross-sectional area, and time. From these added dimensions, the biomechanical properties of stiffness, compliance, energy, hysteresis, stress, viscoelastic stress relaxation (VESR), and creep can be determined.Because muscle comprises deformable material, its length measurement at a given moment in time is always dependent upon the amount of tensile force applied, and that is the equivalent to its tension.
Techniques for measuring muscle length in human subjects is traditionally presented as a one-dimensional concept of muscle length, describing only the measurement of end-range joint angles and does not clearly distinguish between the single and multi-dimensional concepts of muscle length. Muscle extensibility is defined as the ability of a muscle to extend to a predetermined endpoint. In human research, this endpoint is most often subject sensation.
Another concern was that many older studies separated the contractile tissues of muscle from tendons. As we have already discussed, skeletal muscles are intricately woven together by fibrous connective tissue that gradually blends into tendons. Contractile tissue and tendons are sometimes evaluated separately for research purposes, however they cannot be separated during routine and clinical testing procedures.
Studies which demonstrated an increase in muscle extensibility used a sensory endpoint to determine tissue extensibility. That is, they used the participants increased subjective tolerance to stretch as a means to theorize that tissue extensibility was responsible. This merely allows an increase in end-range joint angles.
Most of these theories advocate a mechanical increase in length. The traditional mechanical theories include viscoelastic deformation, plastic deformation, increased sarcomeres in series, and neuromuscular relaxation of the stretched muscle and will be individually discussed.
Viscoelastic deformation: When stretch is applied to a muscle and the muscle is held in the stretched position for a period of time, as is the case with normal static stretching techniques, the muscle’s resistance to stretch gradually declines. This is called viscoelastic stress relaxation and is expressed as a percentage of the initial resistance. Such stretching that uses a fixed torque, can be used to evaluate the property of creep because length gradually increases in response to a constant stretching force.
Muscle length does increase during stretch application due to the viscoelastic properties of muscle. However, this length increase is transient, its magnitude and duration being dependent upon the duration and type of stretching applied. Stretch application typical of that practiced in rehabilitation and sports, the biomechanical effect of viscoelastic deformation can be quite minimal and short lived that it may have no influence on subsequent stretches.
Plastic deformation: Another popular theory suggests that increases in human muscle extensibility observed immediately after stretching are due to plastic (permanent) deformation of connective tissue. The classical model of plastic deformation would require a stretch intensity sufficient to pull connective tissue within the muscle past the elastic limit and into the plastic region of the curve so that once the stretching force is removed, the muscle would not return to its original length but would remain permanently in a lengthened state.
None of the cited evidence to date has been found to support this classic model of plastic deformation.
Increasing sarcomeres in series: There are some animal studies which demonstrated that the number of sarcomeres (contractile units of skeletal muscle) in series (increase in fibers so as to lengthen) of a muscle can be changed by prolonged immobilization in extreme positions. When the muscles are immobilized in fully lengthened positions, there is an increase in the number of sarcomeres in series. However, these muscles demonstrated no overall change in muscle length because increases in the number of sarcomeres in series were offset by a concurrent decrease in sarcomere length. These animal studies suggest that muscles adapt to new functional lengths by changing the number and length of sarcomeres in series in order to optimize force production at the new functional length.
Despite substantial differences between muscle immobilization and intermittent stretching, animal research has been generalized to suggest that short-term (3- to 8-week) human stretching regimens cause similar increases in sarcomeres in series and a concurrent increase in length of the stretched muscles.
Neuromuscular relaxation: The rehabilitation literature often suggests that involuntary contraction of muscles due to a neuromuscular “stretch reflex” can limit muscle elongation during static stretching procedures. It also has been proposed that slowly applied static stretching (used alone or in combination with therapeutic techniques associated with proprioceptive neuromuscular facilitation) stimulates neuromuscular reflexes that induce relaxation of muscles undergoing static stretch. Some author’s believe that neuromuscular reflexes also adapt to repeated stretching over time which enhances the muscles ability to relax and results in increased muscle extensibility.
Stretch reflexes have been shown to activate during very rapid and short stretches of muscles in mid-range positions only, producing a muscle contraction of short duration. The increase in end-range joint angles, therefore, could not be attributed to neuromuscular relaxation.
In the early 1990s, several researchers put these mechanical theories to the test by assessing the biomechanical effects of stretching. By including the dimension of tension in muscle length evaluation, they were able to construct the torque/angle curves and assess biomechanical properties of the muscles before and after stretching. They should have been able to document a right shift of the curve if any of these changes were due to an increase in muscle length. Instead, the only change observed in passive torque/angle curves was an increase in end-range joint angles and applied torque.
Because the end-point of these stretches was subject sensation (pain onset, maximum stretch, or maximum pain tolerated), the only observable explanation for these results was that subjects perception of the selected sensation occurred later in stretch application.
These newer studies suggest that increases in muscle extensibility observed immediately after stretching and after short-term (3-8 weeks, 5 x/wk, 20 minutes per session) stretching programs are due to an alteration of sensation only and not to an increase in muscle length. Also psychological component needs to be accounted for due it being nearly impossible for subjects to not know they are performing a stretching program which alters the outcome. The increased extensibility may be due to a psychological alteration in sensory perception or to a willingness of subjects to tolerate greater torque application.
It has been documented recently that the importance of subject sensation on stretching research has been largely overlooked. Studies evaluating the biomechanical effects of stretching reveal that in controlled clinical settings under the condition of slowly applied passive stretch, it is subject sensation, not the degree of stiffness, that limits joint motion. Researchers have been able to apply passive torque up to the sensory endpoint of pain or stretch tolerance without being limited by stiffness.
Subject sensation is at the very least an important endpoint of the torque/angle curve and may give information regarding how the muscle is routinely used during functional activity. However, extensibility measurements alone are only one dimension of muscle length and may not accurately reflect the actual length of the muscle.
Despite its fundamental role in rehabilitation, as well as sports and fitness, very little is actually known about muscle length. What constitutes optimal extensibility, torque/ angle parameters, and cross- sectional area is still under much investigation.
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