What is Clinical Trigger Point Therapy?
The Origins of Trigger Point Therapy
In the late 1950s, Dr. Janet Travell M.D., serving in a pulmonary and cardiology hospital, became intrigued by the similarity of pain complaints that she observed in patients throughout the hospital.
She was surprised to find that even though a patient might be suffering from a life-threatening illness, what they routinely complained about was simple back, shoulder, or neck pain. She was frustrated that none of these patients had objective evidence of a disease or disorder that accounted for their pain complaint.
While performing physical examinations, Dr. Travell found that nearly all the patients had isolated tender spots in their skeletal muscles, that when pressed on, triggered the patient’s pain complaints. Dr. Travell began a lifelong study of these tender spots, which she termed trigger points, and her research gave birth to Trigger Point Therapy as we know it today.
Dr. Travell was joined in her research by Dr. David Simons M.D., who was a US Air Force flight surgeon when he met Dr. Travell at a lecture she gave in San Antonio in the 1970s.
The two often met in Houston, where Dr. Simons was Chief of Physiometrics Research Laboratory at the Houston VA hospital, and discussed the nature of trigger points. They officially teamed up in 1974 and began several decades of exhaustive medical research in the field of Myofascial Pain.
The two researchers went on to publish the definitive medical textbooks in this field of study; “Myofascial Pain and Dysfunction: The Trigger Point Manual, Volumes I & II”
After contributing a life-time of work and research in Myofascial pain, Dr. Travell passed away in 1997 at the age of 95. Dr. Simons went on to publish a second edition of their textbook, and just recently passed away (2010) at the age of 87.
What is a trigger point?
A myofascial trigger point is typically defined as nothing more than a tender, palpable knot in a muscle. Expanding this simple definition to include an understanding of how a trigger point is formed, and what effect trigger point activity has throughout the body, is important to the clinical process.
Let’s begin to build this clinical understanding by reviewing a few key points about the neuromuscular-skeletal system.
A muscle is composed of many small rope-like fibers, wrapped in a sheath of connective tissue. The muscle fibers are in turn, composed of many smaller fibers called myofibrils.
When a muscle fiber contracts, microscopic elements within the myofibrils called filaments slide past one another in a ratcheting-type mechanism. As these filaments increasingly overlap one another, the myofibril containing them becomes shorter and thicker.
The contraction and relaxation of a muscle fiber is controlled by a motor nerve. The nerve attaches to the muscle fiber by what is known as a myoneural (muscle-nerve) junction. These junctions are typically found in the belly of a muscle and act to convert the electrical impulse of the nerve into a chemical signal that powers the contraction.
A malfunctioning of this myoneural junction is what causes trigger points to form in the muscle. In over-simplified terms, a junction gets stuck in the ‘on’ position, causing the muscle fibers that are controlled by it to remain in a state of constant contraction, forming a micro-spasm in the muscle.
A myofascial trigger point is actually a mass grouping of these micro-spasms and feels like a pea embedded within the muscle to the touch. Palpation will also reveal a tight rope-like band running longitudinally through the muscle, which is a grouping of contracted muscle fibers and is clinically referred to as a taut band.
Palpation of a taut band (or a trigger point) often causes the muscle to “jump” or briskly contract. The clinical term for this reaction is a local twitch response. The elicitation of a twitch response during palpation of a trigger point, or during a trigger point release procedure, is reliable confirmation that the trigger point has been accurately located.
An important clinical consideration must be emphasized here: Trigger points are more accurately described as functional in origin, rather than as physical in origin. Put more simply, the therapist should think of a trigger point less as a “thing”, and more as a process.
Muscle Fibers and Fibrils Diagram
Motor Nerve - Muscle Junction
Micro-spasms in muscle fibers
What Causes Trigger Points?
As previously discussed, trigger points are caused by a dysfunction in the myoneural junction. But from a clinical perspective, it’s important to understand what factors caused the myoneural junction to malfunction in the first place. As a general rule, this malfunction (and the resultant trigger point) is caused by muscular overload.
Muscular overload occurs when a muscle is forced to function in a capacity that it is not conditioned for. The type of overload can vary and is not always just the result of a muscle not being strong enough to perform a certain task.
The factors that can contribute to muscular overload include:
A demand (especially a sudden demand) on a muscle that exceeds its contractile strength.
A demand on a muscle that exceeds its endurance.
A body position that places the muscle in a shortened state for a prolonged period.
A body position that places a muscle in an elongated state for a prolonged period.
Any factor that increases the resting muscle tension.
Some common sources of muscular overload include the following:
Traumatic injury (falls, automobile accidents, etc.)
Heavy lifting- especially lifting and twisting.
Beginning a new exercise program.
Performing repetitive tasks
Antalgic postural distortions or holding static postures for long periods
Stress or emotion-induced muscle tension.
Periods of muscle disuse or immobilization
Referred pain and/or referred motor distortions from other trigger points
In acute pain complaints, trigger point activity in the initially overloaded muscle group is typically apparent in the client’s presenting pain complaint, but in chronic cases, a thorough history and examination may be required to uncover this information.
Types of Trigger Points
Trigger points can be classified into two different types according to their activity; latent or active. Latent trigger points do not spontaneously produce pain unless they are physically compressed by a therapist. Latent trigger points primarily act to increase muscle tension, which makes the muscle more susceptible to over-loading in the future.
Active trigger points are clinically distinguished from latent trigger points by their spontaneous production of pain and other neurological symptoms. The degradation of a latent trigger point to an active trigger point is caused by a muscular overload.
Active trigger points can be further categorized into two subgroups; primary and secondary. A primary trigger point develops from the initial muscle overload. In acute (short-term) pain disorders, a primary trigger point is typically responsible for the client’s presenting pain complaint.
Secondary trigger points form as a result of the primary trigger point’s activity. In chronic (longer-term) pain disorders a secondary trigger point may be partially or completely responsible for a client’s presenting pain complaint.
Secondary trigger points can be classified as either functional or satellite trigger points, depending on how they are formed. Functional trigger points form from a muscular overload that was caused by the activity of a primary trigger point. This overload can be the direct result of referred motor activity from the primary trigger point.
Or, the primary trigger point activity may cause an antalgic (pain-avoiding) posture or alteration in body mechanics. Over time, the altered body mechanics or posture will overload another muscle group, causing a secondary-functional trigger point to form within it.
A satellite trigger point is a secondary trigger point that has become active because it lies within the referred pain zone of a primary trigger point. The projected pain from the primary trigger point produces a ‘guarding reflex’ in the painful region, which overloads the muscle (or muscles) in that region.
Types of Trigger Points Diagram showing the progression of trigger point activity.
For example, a primary trigger point in the upper trapezius muscle refers pain to the temple region of the head. The resulting headache causes the person to unnaturally tense the temporalis muscle, predisposing it to trigger point formation. These temporalis trigger points would be considered satellite trigger points in this situation.
Trigger Point Pathophysiology in the Muscular System
In the previous section, we discussed several of the physical manifestations of a trigger point within a muscle. In this section we will discuss a few of the functional distortions imposed on a muscle by a trigger point.
When a myoneural junction malfunctions, it can affect the functioning of a muscle in three important ways:
It makes it impossible for the entire muscle to completely relax.
It weakens the muscle’s overall contractile force.
It reduces the muscle’s range of motion.
The overall effect of these functional distortions is to significantly increase the resting tension of the involved muscle. This type of muscle tension is not mediated by the typical motor control feedback mechanisms of the nervous system, and is often overlooked as a source of muscle tension in traditional healthcare because of this.
Trigger point induced muscle tension is partially a result of the dysfunctional myoneural junction causing a group of the muscle fibers to remain in a constant state of contraction. This sustained contraction causes a local energy crises, as the blood flow to the muscle fibers is squeezed shut for a prolonged period of time.
As the local blood circulation is impaired, metabolic wastes from the contractile process accumulate, while at the same time, the nutrition and oxygen needed to power the process are prevented from reaching the muscle cells. This process creates a vicious cycle that can perpetuate itself over a sustained period of time.
Though the local energy crisis is an isolated event within the muscle, the muscle tension that it creates represents a significant energetic drain on the body. Though clients may be acutely aware of feeling tired or exhausted, they are rarely aware of muscle tension that has “accumulated” over time.
Ironically, it is not until its trigger points have been deactivated and the muscle obtains a truly relaxed state, that a person becomes completely aware of the muscle tension that they were experiencing. This post-treatment kinesthetic realization can be quite powerful, and typically coincides with healthy change in the client’s emotional state.
Though there is a likely correlation between trigger point activity and the potential for muscle spasm, the traditional Pain-Spasm-Pain Cycle theory has no relevance to trigger point pathophysiology. True neurological muscle spasm, and the pain associated with it, has a different mechanism from trigger point induced pain and/or spasm.
Interestingly enough, trigger point activity is more likely to facilitate spasm in another muscle group, than it is likely to induce spasm in the muscle group harboring the trigger point. This phenomenon is known as referred spasm, and will be addressed in more detail in the Referred Pain & Symptoms section of this article.
Trigger Point Pathophysiology diagram showing the effects that trigger point activity can have on the various systems and tissues of the body.
Trigger Point Pathophysiology in the Nervous System
While much attention is typically given to trigger points as they pertain to the muscular system, trigger points are fundamentally a nervous system phenomenon.
The local energy crisis described previously, not only affects the muscle, but also the nerve supply as well. The metabolic wastes that accumulate in an energy crisis, sensitize and modify the function of any sensory and autonomic nerves in the region.
This aberrant stimulation to the nervous system is thought to cause many of the symptoms associated with trigger points, including local tenderness, referred pain, referred muscle inhibition & spasm, somato-visceral disturbances, and the local twitch response.
Increased muscle tension may also cause a muscle to entrap an adjacent nerve as it passes through the region. Nerve entrapment can produce pain, paresthesia, and/or motor impairment, depending on the type of nerve entrapped. A common example of this involves the sciatic nerve and the piriformis muscle.
Diagram showing how myofascial tension in the Piriformis muscle can entrap the Sciatic nerve.
Trigger Point Pathophysiology in the Tendons, Joints, and Fascia
Trigger point activity can have detrimental affects on tendons, joints, and fascia in both the short-term and long-term time frames.
In the short-term, the stress that a trigger point imposes on a tendon’s attachment can cause what is known as an attachment trigger point. Attachment trigger points typically refer pain in the local region and will spontaneously resolve themselves if the trigger point in the muscle is inactivated.
Over the long-term, muscle tendons under chronic stress from trigger points become inflamed and eventually calcified at their attachments. This calcification is the body’s attempt to strengthen the attachment by adding more bone tissue, causing bone-spurs to develop.
Like tendons, the joints in the body are also affected by trigger point activity. The muscle tension created by trigger points can alter the mechanics of a joint and reduce its normal range of motion. This condition is clinically referred to as an articular dysfunction or subluxation, and can produce referred pain and other symptoms.
Articular dysfunction can be both a consequence of trigger point activity, and a cause of it. It is this interplay between the two disorders that makes chiropractic treatment ineffective at times. If the articular dysfunction is secondary to trigger point activity in the multifidi muscle group, for example, then releasing the articular restriction will only provide a temporary fix.
Additionally, the “lubricating” tissues that line a joint cavity rely on continual joint motion to receive nutrition. The reduced joint range of motion caused by trigger points activity, starves these tissues and causes them to lose their lubricating function. Once this happens, the body will begin to fuse the joint by calcification.
Long-term trigger point induced muscle tension can also cause a distortion in the connective tissue that surrounds and supports the muscles. This connective tissue, called fascia, functions as a soft-tissue framework or “glue” that supports the various tissues and structures of the human body.
Fascia adapts to the mechanical tension imposed on it, by changing its shape and composition. Over time, functional deficiencies in the muscles and joints become structurally reinforced and perpetuated by adaptations in the surrounding fascia.
Attachment Trigger Point
Heel Spur on X-ray
Diagram of Joint Damage
Microscopic view of fascia
Trigger Point Pathophysiology and Posture
Though a person’s posture is a composite of many factors, including emotional and psychological influences, the most clinically apparent factors are acute antalgic (pain-avoiding) changes related to trigger point activity. Observing a client’s antalgic posture and gait, provides useful information in identifying which trigger points are active.
Common postural distortions, such as the head-forward, rounded-shoulder posture, involve neurological patterns of tense muscles juxtaposed with inhibited muscles. These distortions, of intermediate duration, are mediated through referred motor activity from trigger points, and respond well to trigger point therapy and corrective training.
More established postural distortions are typically the result of chronic pathological changes in the muscles, tendons, joints, and fascia.
Because posture plays such a fundamental role in the successful treatment of trigger points, we designed a special protocol to correct the common postural distortions seen in clinical practice.
Trigger Point Referred Pain
The term referred pain describes a type of pain that is experienced in a region of the body that does not contain the source of the pain. This type of pain is typically associated with the body’s internal organs.
For example, you are probably aware that a person having a heart attack will often experience pain in their left arm and jaw. The source of the pain is actually the distressed heart muscle, but the pain is not experienced deep in their chest but rather in the left arm and jaw.
Hence this cardiac pain is termed referred pain because it is projected to the left arm and jaw. In fact, all of the body’s major organs refer pain to some adjacent region of the body, not just the heart.
The “mystery” of trigger point referred pain results from healthcare practitioners failing to recognize that skeletal muscle is an internal organ (the body’s largest organ, in fact), and is therefore capable of producing referred pain.
The projection of trigger point referred pain can make it difficult for clients, and their healthcare professional, to locate the source of their musculoskeletal pain. And this inability to pinpoint the source of the pain, often makes treatment a hit-or-miss proposition.
An analysis of the trigger point referred pain distribution shows that:
56% of trigger points refer pain to both local and distant regions.
24% of trigger points refer pain only to the local region.
20% of trigger points refer pain only to distant regions.
As an example of the referred pain phenomenon, let’s examine the typical neck-ache. Common sense suggests that if the neck region is painful, then the problem lies within the neck. A physician might examine the bones, joints, nerves, and muscles of the neck in an attempt to identify the source of the neck pain.
But the most likely cause of the neck pain (statistically speaking), is trigger point activity in the lower trapezius muscle. Thus the actual source of the neck pain is found not in the neck, but between the shoulder blades.
This all seems rather counterintuitive, unless you ask the question “what purpose does this pain referral serve?” The purpose of referred pain, like all pain, is to protect injured tissue.
In this case, the specific goal of this referred pain is to limit the use of the trapezius muscle, so that it can heal.
As the trapezius muscle functions to move the neck and head, its pain is referred to these structures to discourage movement of them. As a result, people experiencing neck pain and headaches, naturally want to lie down and immobilize their head, and this allows the Trapezius muscle to rest and recover from its overload.
But trigger points don’t just refer pain, they also refer motor distortions to other muscles. These motor distortions cause some muscles to become neurologically inhibited or weak, and other muscles to become tense or prone to hyperactivity/spasm. These patterns of motor distortion serve the same purpose of referred pain; to encourage rest and recovery of the muscle harboring the trigger point.
In summary, a therapist’s understanding of trigger point referred pain patterns is fundamental to their ability to identify the source of a client’s musculoskeletal pain and to address it effectively.
Trigger Point Referred Pain Distribution Diagram
Trapezius Trigger Points locations and referred pain projections.
Trigger Point Symptoms
Besides referred pain, trigger points are capable of producing other symptoms that are not typically associated with the muscular system. These symptoms are generated by referred motor and sensory distortions imposed on the autonomic nervous system by trigger point activity.
Some examples of these other symptoms include:
Numbness or tingling
Balance problems (vertigo) and dizziness
Excessive eye tearing
Abdominal bloating, heartburn, and vomiting
Gynecological disorders such as dysmenorrhea
Trigger Point Treatment
Before detailing the various Trigger Point Treatment methods, it’s important to address a common technique that is used to relieve muscular ailments; muscle stretching.
General muscle stretching is an ineffective technique for releasing trigger points. Stretching a muscle with an active trigger point typically only serves to further aggravate the trigger point, therefore it should be avoided as a trigger point treatment technique.
There are several trigger point release techniques that employ muscle stretching effectively, however. All of these techniques utilize augmentation techniques that dramatically improve the clinical effectiveness of the stretch technique. Several of these specialized stretching techniques are detailed in this section.
Spray and Stretch Treatment
The Spray and Stretch trigger point release method was developed by Dr. Travell and involves applying a spray-on refrigerant as a surface anesthesia while stretching the muscle group containing the trigger point(s).
The spray is directed on the skin region where a trigger point refers pain, and serves to temporarily block (or distract) the perception of pain by the nervous system. The actual release of the trigger point is achieved with the muscle stretch, but it is the spray’s blocking of the pain-reflex that enables the stretch to release the trigger point.
Spray and Stretch is a very effective method for releasing trigger points, but its clinical application requires a great deal of skill and experience to be consistently effective.
Trigger Point Injections and Dry Needling
A trigger point release method often employed by physicians involves using a needle to physically break the micro-spasm of the trigger point. Often this technique includes injecting a very small amount of a local anesthetic into the trigger point.
Dry needling uses a small needle, without an injection, to inactivate the trigger point. Injection and dry-needling techniques are equally effective, but there is typically more post-treatment soreness associated with dry-needling.
Obviously both of these release methods require a high degree of skill and extensive training. And as invasive procedures, they carry risks not associated with manual release methods.
Trigger Point Pressure Release and Micro-stripping Treatments
Also known as ischemic compression, this widely utilized release technique involves applying specific manual pressure to release the contracted fibers of a trigger point. There are two effective variations of this method, the sustained pressure technique, and the micro-stripping technique.
The sustained pressure technique involves the therapist using a thumb, fingertip, or elbow as a contact on the trigger point, and slowly applying pressure, holding the pressure for 4-8 seconds, and then slowly releasing it. The therapist then repeats the pressure application 3-6 times.
Which contact a therapist chooses to use, how long the pressure is held, and how many pressure applications are needed, are primarily determined by the specific trigger point being released. The individual preferences and characteristics of both the client and therapist may also help determine these factors as well.
The micro-stripping release method, popularized by the work of Clair Davies, involves using a supported thumb contact (thumb-over-thumb) to apply a short stripping stroke across the trigger point, parallel with the muscle fibers. This technique is very effective at releasing the contracted fibers of the trigger point.
To perform this technique, the therapist applies pressure to one side of the trigger point, and then slowly moves that pressure through the trigger point to the other side. It’s important to clarify that the contact never slides across the skin, as in a traditional muscle stripping techniques, but rather the skin is moved across the underlying muscle.
Dr. Perry applying a trigger point pressure-release treatment with her elbow
Dr. Perry performing a micro-stripping trigger point treatment
Typically, this technique is more effective in releasing trigger points that lie in the more superficial muscle groups. Employing a mixture of sustained pressure and micro-stripping release techniques can significantly reduce therapist fatigue.
The advantages of using these pressure release techniques are:
They are simple techniques that are easy to learn and apply.
The referred pain produced with these techniques confirms for the client that the therapist has located the source of their pain.
The disadvantages of using these pressure release techniques are:
These techniques are painful for the client, and require the therapist to modulate their pressure to the pain tolerance of the client .
Their application can be fatiguing for the therapist if proper biomechanics are not employed.
Trigger Point Stretch Release Treatment
A type of muscle stretching known as Post-Isometric Relaxation (PIR) can be an effective trigger point release method. PIR was first introduced by Dr. Karel Lewit, and is particularly suited for releasing trigger points in muscles that are difficult to address with pressure release techniques.
The basic PIR method is as follows:
Instead of directly stretching a muscle containing trigger points, a series of gentle isometric contractions are imposed upon the muscle at its full pain-free length.
The relaxation that occurs after each contraction, affords the muscle with some additional pain-free range of motion.
The therapist passively stretches the muscle a little further between each contraction to capture this additional range of motion.
The contract-relax-stretch cycle continues until the muscle progressively achieves a normal pain-free range of motion.
The clinical focus of PIR is on the relaxation phase of the cycle, and it employs several augmentation techniques such as coordinated breathing and eye movements to enhance the relaxation response of the muscle. The isometric contraction is limited to 10-20% of the client’s contractile strength to avoid aggravating the trigger point.
The application of this technique does require some technical skill on the part of the therapist, but as a somewhat pain-free method of trigger point release, it has real clinical value. A hybrid technique that we are developing, combining PIR with the coordinated application of pressure release techniques, has provided some remarkable clinical results in our daily practice.
Clinical Trigger Point Therapy Protocols
The majority of pain complaints seen in clinical practice are typically complex, multi-trigger point phenomenon. The effective treatment of complex complaints requires the therapist to understand the many ways trigger points can interact with one another, and to address the client’s pain complaint in a comprehensive and systematic manner.
Factors that need to be considered in this clinical process include:
Which trigger points are responsible for the client’s presenting pain complaint?
Which trigger points resulted from the initial muscular overload?
What satellite trigger points are likely to develop from the client’s referred pain?
Which trigger points are likely to be activated because of biomechanical and postural distortions caused by the current trigger point activity?
Which trigger points should be released first, second, third, etc?
Because there are so many factors that need to be considered in the clinical process, we formulated comprehensive protocols for the general pain complaints to ensure consistent results in our daily practice. We have found the protocol format effective in both the practice of and teaching of trigger point therapy.
Each protocol is designed to resolve the most complex form of a particular pain complaint in the most efficient manner possible. Though all the steps in a given protocol may not be necessary in all clinical situations, we have found that the client always benefits from a comprehensive clinical approach.
These protocols are the foundation of our Clinical Trigger Point Therapy System, and are the reason for its unique ability to succeed when other approaches fail.