Overview of Muscle Pathologies

By Whitney Lowe
[Clinical Explorations]

When a client presents with soft-tissue pain, muscle problems are usually one of the first issues massage therapists will suspect. The focus of massage training emphasizes muscles, so it is no surprise that muscle dysfunction is something we would focus on. Muscle dysfunction or injuries also account for a large number of common soft-tissue pathologies, so emphasis on muscle involvement is certainly warranted.

Muscles are likely involved in many complaints, but what is the actual pathology affecting those muscles? It is essential we understand what type of muscle problem may be at the root of our client’s complaint. There are many types of muscle dysfunction, which we’ll explore in greater detail for a better understanding of what may be happening with our clients.

Muscular Hypertonicity

Muscular hypertonicity is the most common muscular dysfunction we see as massage therapists. Almost every client will complain of certain areas that feel tight and painful. Despite occurring so frequently, muscular hypertonicity is not often diagnosed as a primary pathology. It is usually considered a secondary response to other problems. Perhaps the idea of tight muscles is too simple to be considered an orthopedic “condition”?

The term muscle tension is frequently used to indicate muscular hypertonicity. However, the term tension can be confusing. Biomechanically, tension indicates a pulling force. So technically, muscle tension would indicate a pulling force on the muscle.

Muscle tightness results from an increased rate of contraction stimulus. As a result, the muscle has a higher degree of resting tonus than it normally would. There are various factors that can lead to increased contraction stimulus and hypertonicity. Mechanical overload, such as holding a challenging posture for prolonged periods, is a common cause. For example, excessive forward-head posture associated with a poorly designed computer workstation can lead to excess hypertonicity.

Mechanical stressors are not the only cause of increased hypertonicity. Chemical stresses, such as metabolic challenges or consumption of substances like caffeine or nicotine, also play a role in the development of hypertonicity. Psychological stress also frequently leads to excess hypertonicity. Those who experience high levels of stress in their home or work lives frequently report specific regions of their bodies that feel tight or painful when these stresses increase.

Myofascial Trigger Points

Another common muscular dysfunction is the myofascial trigger point (MTrP). They are defined as “hard, discrete, palpable nodules in a taut band of skeletal muscle that may be spontaneously painful (i.e., active), or painful only on compression (i.e., latent).”1 There is extensive debate in the scientific community in recent years about the actual physiology of trigger points.2 We still have a lot more to learn about what is actually going on below the skin with this condition. We do know there are clearly identifiable areas of tissue density that massage therapists are able to palpate. Pressing on these areas produces common characteristic responses, so something is happening there. Exactly what that something is remains for additional research.

Researchers have found altered cellular muscle metabolism at the site of MTrPs, but it has not been determined whether this is a cause or an effect. In other research, electromyographic activity at the site of the MTrP also seems altered. Also notable is that pain-referral patterns appear to be related to perception errors by the brain.

MTrP identification is primarily based on clinical examination and not on reproducible diagnostic testing. Consequently, enhanced palpation skills are essential for identifying and appropriately treating MTrPs. Massage therapists play a critical role in the investigation of trigger-point phenomena because we spend more time providing detailed soft-tissue palpation than any other health-care profession. Unfortunately, most studies on trigger-point phenomena have not included massage therapists as practitioners. Not using massage therapists in these studies is critical because identification of these nodules within muscle may not be picked up by someone with less palpation skill and experience.

Knowing the characteristic referral patterns for MTrPs is helpful in recognizing them. There are charts and maps of MTrP pain-referral patterns that are useful references. However, practitioners are encouraged to use these diagrams only as a starting reference point since pain referral patterns can differ between individuals.

Muscles develop trigger points in reaction to stress. As with muscle hypertonicity, these stresses often involve biomechanical overload on the muscle but could also be chemical, thermal, or psychological. Referred pain created by a trigger point can increase muscle tightness either in the muscle housing the trigger point and/or in other tissues that lie within the pain referral zone. Muscles that perform similar actions as the affected muscle can also develop trigger points while compensating for the dysfunction.


Muscular atrophy is a decrease or wasting of muscle size and is caused by denervation or disuse. Denervation is a loss or impairment of motor nerve supply to the muscle and results from nerve compression or tension syndromes, systemic disease, or damage to the nerve, central nervous system, or neuromuscular interface. The lack of proper neurological stimulation leads to loss of size and contractile strength, as well as to abnormal biomechanics.

Disuse atrophy is relatively common and can also lead to other biomechanical problems from the muscle impairment. Disuse atrophy often develops from a traumatic injury where a limb must be immobilized for a long period. Atrophy can also develop when movement is restricted due to pain or even fear of a movement being painful (kinesophobia). Disuse atrophy advances quickly, with the muscle losing strength and size in a relatively short period of time. Interestingly, it doesn’t seem to affect all muscles equally.

 Disuse atrophy develops in the primary antigravity muscles more rapidly than other muscles, although the reason is not established. Antigravity muscles are those that are responsible for resisting the downward pull of gravity while in the normal upright position. For example, disuse atrophy affects the quadriceps more than the hamstring muscles because the quadriceps are antigravity muscles. The effects of disuse atrophy are more pronounced if the muscle is immobilized in a shortened position. Immobilization for knee injuries, for example, frequently requires the knee to be set in an extended position where the quadriceps are shortened and the hamstrings are lengthened, which accelerates the quadriceps atrophy.


A strain, sometimes referred to as a pulled muscle, is a muscle injury produced by excessive tensile stress that causes fibers within the muscle to tear. A muscle strain generally does not result from excess stretch alone but from a combination of tensile load and active muscle contraction. Due to muscle mechanics, strains are more likely when the muscle is in eccentric contraction than concentric or isometric. Remember that muscles are increasing in length during an eccentric contraction, so the increasing muscle length, along with the contraction force, contributes to the strain injury.

Strains result from muscular fatigue, lack of proper conditioning, loss of flexibility, poor recovery after exercise, inadequate warm-up prior to vigorous activity, high-force loads, and repetitive overuse. Any muscle can experience a strain, but certain muscles are more susceptible. Those exposed to high-force loads while lengthening, such as the hamstrings or shoulder muscles, are commonly strained. Small muscles, like the intrinsic spinal muscles, are also susceptible to strains due to their small cross section and the repetitive postural loads that can cause the fibers to fatigue.

When a muscle strain occurs, fibers of the muscle or tendon are torn along with the connective tissue, capillary beds, and nerve endings in the area. As a result, blood from the broken capillaries can leak into the interstitial space, causing a bruise. However, bruising is not always visible, so lack of visible bruising does not mean muscle damage has not occurred.

Muscle strains are most often acute injuries. However, repetitive tensile forces on the muscle can cause small degrees of fiber tearing and produce a chronic strain. Strains, both acute and chronic, frequently develop in muscles that have previously experienced a strain. Scar tissue that repaired the original strain is a weak point in the muscle’s continuity and is therefore vulnerable to re-injury.

There are three grades of muscle strain: first degree or mild, second degree or moderate, and third degree or severe. Characteristics of these three grades of muscle strain are shown in Grades of Muscle Strain. In a first-degree strain, few muscle fibers are torn. While there may be some post-injury soreness, the individual usually returns to normal levels of activity quickly. With second-degree strains, more fibers are involved in the injury. There is a greater level of pain with this injury and a clear region of maximum tenderness in the muscle tissue.

A complete rupture of the muscle-tendon unit occurs with a third-degree strain. Some strains are classified as third degree even though the muscle still has some fibers intact because the damage is so extensive. There is likely to be significant pain at the time of the injury. Pain can be significantly less sometime afterward in a complete rupture because the ends of the muscle are fully separated, and limb movement does not cause additional tensile stress to any remaining fibers.

Third-degree strains generally require surgical repair. In some instances, surgery is not performed because the muscle does not play a critical role in that limb’s movement, or the potential dangers of surgery outweigh the benefits. Ruptures to the rectus femoris are an example of this, because the other three quadriceps muscles make up for the strength deficit caused by the loss of the rectus femoris. Another example is a complete rupture of the long head of the biceps brachii, which causes the muscle to bunch up in the middle of the upper arm in what is called a “Popeye deformity.” Surgery to repair this injury is often not chosen because the brachialis can do a great deal of the elbow flexion force generation.

If the strain is severe, a defect in the continuity of the muscle fiber may be apparent either visually or with palpation. When visible, the defect looks like a divot or dent in the muscle. Some redness, which is indicative of an inflammatory reaction, may also be visible.

The muscles most susceptible to strain injuries are multiarticulate muscles, which are those that cross more than one joint. The more joints crossed by a muscle, the greater their vulnerability to strain injury. The muscle cannot be fully stretched across all joints at the same time, so it is susceptible to tearing from excess tensile stress.

Strains can develop in any part of the muscle but ordinarily occur at the musculotendinous junction. The junction of muscle and tendon places one tissue with higher pliability (muscle) directly adjacent to another with limited pliability and more tensile strength (tendon). As a consequence, the point of interface between the two tissues becomes a site of mechanical weakness where the strain occurs.


A contusion results from a direct blow to the muscle that causes disruption in the fibers and/or their neurovascular supply. Bruising forms as the blood from damaged capillaries leaks into the muscle tissue and interstitial space. Muscle contusion healing depends on the severity of the impact trauma and the level of disruption of muscle fibers and neurovascular structures.

In some cases, a severe contusion can develop into a condition known as myositis ossificans. During the healing process, ossification (bone tissue development) takes place within the muscle injured by the contusion. Awareness of this condition is important because deep pressure on an area with myositis ossificans can cause further muscle damage and be detrimental to the healing process. The anterior muscles of the body vulnerable to direct blows, such as the quadriceps group, biceps brachii, brachialis, and deltoid muscles, are most at risk.

Because we focus so much on muscles with our treatment, it is valuable to have a good understanding of how muscles function in a healthy system, as well as common muscle pathologies that may affect them. A good understanding of these different muscle pathologies helps us choose treatment strategies that are most appropriate and will be most helpful for our clients.


Grades of Muscle Strain

First Degree

Few fibers torn

Minor weakness

Minor spasm

Minimal loss of function

Minor swelling

Minor pain on MRT

Pain on stretch

No palpable defect

Decreased ROM


Second Degree

About half of fibers torn

Moderate to major weakness

Moderate to major spasm

Moderate to major function loss

Moderate to major swelling

Moderate to major pain
on MRT

Pain on stretch

No palpable defect (usually)

Decreased ROM

Third Degree

All fibers torn

Moderate to major weakness

Moderate spasm

Major loss of function

Moderate to major swelling

Minor or no pain on MRT

No pain on stretch (if muscle is only tissue injured)

Palpable defect present

Increased or decreased ROM


1. Jay P. Shah et al., “Myofascial Trigger Points Then and Now: A Historical and Scientific Perspective,” PM&R 7, no. 7 (February 2015): 746–61, https://doi.org/10.1016/j.pmrj.2015.01.024.

2. John L. Quintner, Geoffrey M. Bove, and Milton L. Cohen, “A Critical Evaluation of the Trigger Point Phenomenon,” Rheumatology 54, no. 3 (March 2015): 392–99, https://doi.org/10.1093/rheumatology/keu471.

Whitney Lowe is the developer and instructor of one of the profession’s most popular orthopedic massage training programs. His text and programs have been used by professionals and schools for almost 30 years. Learn more at www.academyofclinicalmassage.com.