Amanda Sutton and Dana Whitlock


Biologic Basis

Massage has many definitions and is employed by many practitioners of various backgrounds. The working definition used in this chapter is that massage is the manipulation of the soft tissues of the body. The use of massage has been well received in the human field and, despite a paucity of research, it has continued to be developed and explored.

The word massage is derived from the Arabic word mass, which means “to press.” Many ancient civilizations developed a system of massage, which was used for various medical conditions. Just Lucas Championnies (1843-1913) used it in the management of fractures in the United States, and it was advanced by Mary McMillan, director of physical therapy at Harvard Medical School. Dr. JB Mennell described physical treatment by movement, manipulation, and massage, which was first published in 1917. There has been variable interest in massage by medical establishments in the twentieth century, but interest in complementary medicine has grown in the United States. The American Massage Therapy Association was founded in 1943 and had grown to more than 58,000 members by 2009.

Massage is now incorporated along with the medical management of human patients for pain relief and cases of decreased mobility. It is used as a prevention measure and in the management of competitive athletes. It is also incorporated into most chiropractic, physical therapy, and osteopathic manual therapy approaches.

Biomechanics of Connective Tissue

Massage must be directed toward a specific purpose and should be aimed at promoting physical and psychological change.

The main constituent of connective tissue is collagen. Its function is to resist axial tension, and it exhibits a stress-strain behavior (Box 27-1). Microscopically, collagen fibers are arranged in bundles and have a crimped appearance. Type I collagen is in the dermis and fascia and gives support and resistance to tension.

The basal lamina of epithelial tissue contains type IV collagen, which supports the epithelial cells. Hydrogen cross-links are formed between chains and between molecules, giving stability at fibril levels, assisting in the formation of collagen fibers. They allow the tissue to function under mechanical stress.

The orientation of the fibers depends on the stresses to which the fibers are subjected; connective tissue must be pliable, yet very strong. A stress-strain curve demonstrates the behavior of biologic materials. When a longitudinal stress is applied to collagen, the tissue responds by elongation, which occurs in the toe region of the curve (Figure 27-1). Elongation occurs as a result of straightening of the crimped fibers, and probably also as a result of some interfibrillar sliding and shear of ground substance, which flows between the collagen fibers.

Massage produces most of its effects in the toe region of the stress-strain curve. Care should always be taken to not overstretch the tissues and to avoid damage to the internal structure of connective tissue fibers. Therefore the end feel of the tissues must be understood to avoid damage to connective tissues.

Permanent deformation is termed plastic deformation, which occurs with microfailure and disruption of collagen cross-links. The undamaged fibers absorb a greater proportion of the load as a new length is established, which reflects the balance between elastic recoil and the resistance of the water and glycosaminoglycans to compression.

Biologic materials also have viscosity, a property of fluids of resistance to flow, and elasticity, a property of solids. Together, these result in the viscoelastic properties of tissues. The response of tissues to loading depends on how quickly the load is applied or removed. The faster the repetitive loading and unloading, the stiffer the material behaves. With rapid loading, friction results and tissue temperature rises. Energy is dissipated as heat when the tissue is returned to its original length. This is referred to as hysteresis.

This is relevant in the application of massage because it is important to be sensitive to the stiffness of tissues. If a low constant or repetitive load is maintained over a long period, the elongation of tissues that occurs is by creep. Conversely, if the tissue length is held constant, elongation occurs by relaxation. Massage produces low, repetitive loads over the medium term and may cause a nonpermanent creep response. Rapid loading of tissues during massage is undesirable because of increased tissue stiffness as a result of their viscoelastic properties. Also, dry tissue results in less compliance and elongates less readily. These are important facts for deciding the rate of massage application.


In humans, one tenth of the tissue fluid is removed by the lymphatics. Understanding lymphatic anatomy, physiology, and function is necessary for successful massage. The rate of flow is determined by the interstitial fluid pressure and lymphatic pump activity.

Increased lymphatic flow is caused by the following:

Massage has been shown to increase lymph flow rate by 22-fold, lymph colloid concentration by 47 times, and leukocyte counts by 8.5 times.1 It is believed that when tissues and fluid are compressed against the outer surfaces of the larger lymph vessels, lymph flow is impeded. This results in an increase in interstitial fluid pressure slightly above atmospheric pressure. Massaging may increase interstitial fluid pressure and help to move fluid into the lymphatic system. By massaging in a distal to proximal direction, it is proposed that fluid is moved from the extremity toward the central body core. This supports the practice of applying massage in a distal to proximal direction. Other controlled studies show that massage does not improve lymph drainage in certain situations, such as cancer. A study of women with breast cancer–related lymphedema evaluated the effect of compression garments with or without manual lymph drainage (massage). It was concluded that compression garments improved lymphedema, but there was no additional benefit of massage in relieving limb edema in women with breast cancer.2

Circulatory Effects

The pressure of the massage itself increases pressure within the tissues. Pressure gradients are created between the tissue spaces and vessels. As the hands are moved, changes in tissue pressure occur, creating fluctuating pressure differences between one area of tissue and another. It is believed that fluid moves constantly from tissues to vessels and back again, as it flows from areas of high pressure to areas of low pressure.

During an actual massage session, various massage manipulations are employed that are complex and involve a combination of squeezing, stretching, pulling, and traction forces, with movement occurring in different directions and in different tissue planes. Therefore there will be complex repetitive pressure changes occurring in varying directions and at different tissue depths. This is likely to have an effect on fluid interchange, whereby fluid is pushed from the tissue spaces into the vessels, toward the lymph nodes and heart, and new fluid is pushed or drawn into the spaces. Massage is believed to replenish the fluid in the spaces, producing a flushing effect, which brings in additional nutrients. There is evidence in humans that chemical irritants in the tissues (e.g., substance P, prostaglandins) and waste products of metabolism may decrease pain threshold by sensitizing free nerve endings. Replenishing tissue fluid and removing inflammatory products may reduce this effect, preventing or reducing some types of chronic pain. By removing metabolites and chemicals from muscles and “flushing” the muscle tissue with new circulation, muscle soreness following exercise may be reduced. However, controlled studies have not been able to demonstrate that massage reduces metabolites following exercise.3,4 Studies involving Doppler ultrasound have failed to demonstrate an effect of massage on muscle blood flow.5,6

Tissue Movement

As the hands move along the superficial tissues, pressure to the tissues increases, and layers of tissue are moved. A light glide causes movement of the epidermis. If friction is maintained between the therapist’s hand and the patient’s skin, the epidermis moves with the hand and is gently stretched. There will also be some movement of the dermis because of the traction between the two layers. More pressure with friction, although still very light, results in traction between the dermis and the subcutaneous tissues. The end-feel of the stroke is when this traction reaches its limit and all layers are stretched.

Massage involves the interaction of energy between the person applying the massage and the dog, and the effects of touch to induce relaxation, communication, and a sense of general well-being. It may also produce movement of the tissues in subsequent layers as a result of traction of the tissue interfaces. Sensory and autonomic nerves may be stimulated, inducing changes in the nervous and circulatory systems, and movement may be affected in abnormal tissue, such as scar tissue or layers of adherent tissues. Reed and Held7 found no consistent systemic effect on autonomic nervous system parameters either acutely or cumulatively when comparing connective tissue massage and a placebo treatment (sham ultrasound) in healthy middle-aged and geriatric humans.

Therapeutic Effects

Massage is generally enjoyed by small animal patients and helps to relieve distress, anxiety, and discomfort. There are many postulated effects of massage reported in the literature. Unfortunately, many of these have not been substantiated by systematic scientific investigations.

Stroking young animals results in a reduction in the animal’s physiologic response to stress, demonstrated by a decreased output of adrenocorticotropic hormone.8 Young animals that are handled also show greater development of the cortex and the subcortex of the brain. They learn faster and have a more advanced stage of neural development than nonhandled animals.9 Resistance to infection later in life may also be beneficially influenced by cutaneous stimulation experienced by the infant animal.10

If a hand is placed over the surface of a dog’s skin, heat is felt between the two surfaces. If the hand is placed on the skin and held still, this heat increases. Rubbing over the surface of the skin causes friction, and this results in an even greater increase in heat. Heat is a form of energy, and some schools of massage, particularly those grounded in Eastern practices, use the energy field that exists around the body. This is sometimes referred to as an electromagnetic radiation around the entire body. It is felt as heat and can be felt a small distance from the body. Some also believe that other forms of energy fields run through the body, along specific pathways known as meridians. These are used in acupuncture and reflex therapy treatments.

Most of the research on the effects of massage has been done in humans. Most studies have evaluated healthy individuals, which may be misleading because physiologic compensatory mechanisms are extremely efficient in healthy tissues and any alterations in local blood flow may be compensated for by autoregulatory processes. Most of the research studies have also been performed on small groups and often without control groups. One study by Hansen and Kirstensen11 gave little detail concerning the massage itself, such as the amount of pressure applied. Although the research supported the concept that massage increases blood flow in muscles, the lack of information regarding the type of massage and length of treatment make interpretation of the results difficult.

Changes in blood constituents following massage have provided information regarding the mechanism of action of massage.12 Ernst13 found that a standard 20-minute massage treatment reduced the hematocrit and blood and plasma viscosity. It is believed that the fluid immediately surrounding poorly perfused vessels has low viscosity because of decreased cellularity and that the vasodilatation caused by massage aids in the recruitment of dormant vessels. It is desirable to increase local circulation to promote healing. The mechanical effect of the massage helps to remove low-viscosity tissue fluid into the circulation. The changes in blood detected within the vessels in this study support the belief that massage produces a flushing and mechanical effect on the circulation. In a more recent study, Hinds and colleagues6 showed no difference in femoral arterial blood flow, quadriceps muscle temperature, blood lactate levels, heart rate, or blood pressure when comparing post quadriceps exercise and massage to exercise and rest. They did show that skin blood flow and skin temperature were both significantly elevated in the massage group. They hypothesized that this potential diversion of blood flow away from the muscle could have a deleterious effect to recovering muscle tissue. They did not demonstrate a decrease in muscle blood flow, however, so this hypothesis is not supported by their work.

In a Cochrane database review, Furlan and colleagues14 critiqued 13 randomized trials and concluded that massage might be beneficial in the treatment of low back pain in acute and chronic cases, especially when combined with exercise and education.

Effects on Muscle

Massage may also affect skeletal muscles. Muscles have a natural resting tone that may be increased in postural muscles by external influences, such as cold or stress. This occurs because of the interaction of the muscle spindle and the central nervous system. Stretching a muscle may stimulate the muscle spindle and cause a reflex muscle contraction while reflex inhibition of the antagonist occurs. Massage may add an external stimulus to sensory organs and either increases muscle tone by stimulation or reduces it, probably by facilitating an accommodation of the spindle, causing it to reset at a lower threshold of excitability.

It is believed that the circulatory effect of massage may reduce muscle soreness and therefore aid clinical signs associated with muscle injury or postexercise recovery. Danneskiold-Samsoe and colleagues15 studied the effects of massage for shoulder and back pain in humans. Blood samples were evaluated for myoglobin concentrations. There was a statistically significant effect, with peak myoglobin concentrations occurring within 3 hours of the massage. Myoglobin concentrations gradually decreased; after seven treatments, there was no difference. In a systematic review of the literature published in 1998, Ernst16 concluded that most studies evaluating the effect of massage on delayed-onset muscle soreness were methodologically flawed, findings were inconsistent between studies, and, although there appeared to be some potential for a positive effect, the evidence was not convincing and warranted further controlled investigation.

Jacobs17 advocated the use of massage for the relief of spasm of unknown cause but which resulted in a self-perpetuating muscle spasm cycle (Figure 27-2). Massage is also said to reduce tone in muscles that are tense or in spasm and to reduce the soreness and tenderness of exercised muscles. It is also used to prepare muscles for exercise. Hernandez-Reif and colleagues18 found that children with cerebral palsy who received 30 minutes of massage twice weekly for 12 weeks had decreased muscle spasticity of the arms, decreased arm muscle and overall tone, increased hip extension range of motion (ROM), and improved fine and gross motor function when compared with children with cerebral palsy who received 30 minutes of reading twice weekly.

Jones and Round19 discussed the process by which an analgesic substance, possibly potassium, is released when muscles maintain excessive tone or static contraction for prolonged periods. Eccentric exercise of muscles, which generates high forces in muscles, produces delayed-onset soreness and a feeling of stiffness. Jones and Round19 explained this by identifying swelling in muscles and inflammation of the connective tissue. Massage may help reduce or prevent the initial tenderness. It is also believed that massage may help to prevent subsequent postexercise pain. Regular massages may make the muscles softer and more pliable, and the stretching manipulations may increase extensibility and strength in the connective tissues.15 Willems and colleagues20 demonstrated decreased muscle soreness in portions of the quadriceps muscle (vastus lateralis and rectus femoris), but not in the vastus medialis after massage following eccentric exercise–induced muscle soreness. They also demonstrated improved vertical jumping performance in the massaged leg 48 hours after massage when compared with the nonmassaged leg. Mancinelli and colleagues21 showed significant effects of massage versus control in vertical jump displacement, perceived muscle soreness, and algometer muscle pain readings, but not timed shuttle run in women collegiate athletes.

Pain experienced after exercising with the muscles in a lengthened position may also be due to inflammation of the connective tissue rather than muscle damage. Massage may assist by increasing pliability in the connective tissue around the muscle fasciculi. Massage assists mobility between the interfaces within the muscle and also stretches any fibrous adhesions or scarring in the tissue.

The effects of massage on the Hoffman (H) reflex, which indicates the excitability in α-motoneurons or anterior horn cells, has also generated interest. Goldberg and colleagues22 studied the effects of massage on healthy people and patients with spinal cord injuries. They applied one-handed petrissage to deep and superficial tissues. There was a 49% reduction in H reflex activity with deep massage, and a 39% reduction with light massage. From this study, it was concluded that stimulating cutaneous mechanoreceptors and pressure receptors reduces H reflex activity. Sullivan and colleagues23 also demonstrated a reduction in α-motoneuron excitability of massaged muscles.

Effects on Pain and Sensation

The effects of massage on connective tissues, which helps to reduce muscle spasm and soft tissue discomfort, have already been discussed. However, Ueda and colleagues24 demonstrated that postsurgical massage may facilitate the regression of sensory analgesia following an epidural block.

Carreck25 evaluated the effect of massage on levels of pain perception in humans. She found that pain threshold was raised to significantly higher levels in the massage group and this work suggests that massage may be used to help manage pain and reduce treatment soreness.

Massage may cause traction at tissue interfaces. Horizontal plexi lie at interfaces in the tissues and gentle pulling on these vessels may stimulate the accompanying sympathetic nerves, which supply the mechanoreceptors. These receptors may be distorted by the massage, possibly lowering mechanoreceptor sensitivity and reducing pain and tenderness. If delayed-onset pain in the muscle is caused by connective tissue inflammation, the flushing effect in the surrounding fluids and removal of inflammatory mediators may increase the speed at which the inflammation resolves.

Effects of Massage on Connective Tissue

Following injury or disease, inflammation causes increased vascular permeability. The resulting edema contains fibrinogen, which may result in formation of fibrous tissue. Adhesions form within the tissues, binding tissue interfaces. These adhesions prevent normal sliding of tissues on each other and also reduce the ability of the fibers to spread apart. Massage is described as being able to stretch tissues that have become short, tight, or adhered. Petrissage massage stretches and pulls the tissues in various directions and mobilizes the adjacent connective tissue fibrils. The molecular cross-bridges between fibrils may be influenced and plastic changes may occur; their length may be maintained or increased because of elongation or creep. Mobility may also be increased at the fibrous cross-bridges between fibers and areas of adhesions by stretching connections between the fibers. This facilitates spreading and sliding at tissue interfaces, and longitudinal elongation helps to increase flexibility.

Following surgery, scars may form with adhesions of various tissue layers to the underlying tissues. Massage helps mobilize and soften adhesions by elongation, creep, and increased fluid exchange of tissues. Collagen fibers align themselves along lines of stress. Techniques that stretch the fibers and adhesions in different directions eventually restore their mobility, promoting remodeling along the lines of normal stresses.

Following injury, it is important to maintain local flexibility of the involved structures to assist overall suppleness and to reduce the possibility of reinjury resulting from decreased extensibility of normal and scar tissues. Massage should be used to promote the functional recovery of structures and prevent reinjury by maintaining mobility at the interfaces, both inside and outside the affected structures. Massage should be combined with controlled longitudinal stretching exercises.

One technique to mobilize scar tissue is deep-friction massage.26 It is applied at 90 degrees to the fibers and delivers a stretch and separation between individual fibers. Deep friction is believed to create movement and induce reactive hyperemia,27 stretch cross-bridges between fibers, and stretch adhesions within the structure. Fibrous scarring in tendons and their interfaces may become more pliable with massage. Although one researcher has suggested that deep friction application may result in some analgesia to the area,28 there is little evidence to support this claim. Although many theoretical effects of massage have been put forth, there is little high-quality research evidence to support these claims. A Cochrane review evaluating the effect of deep transverse friction massage for treating tendinitis found no evidence of benefit with its use and concluded that there was the need for a high-quality randomized study using validated outcome measures to further evaluate its usefulness.29

How Massage Works

Massage may have immediate benefits to a patient, but it usually takes regular treatments to bring about significant improvements in a particular condition. Initially, massage may provide relief from pain, reduce tension, and help to sedate the nervous system. When pain has subsided, attempts to correct the underlying cause of the problem may begin. Healing is stimulated by both mechanical and reflex actions.

The mechanical effect of massage to the soft tissues may help to relieve tense muscles through relaxation, decreased pain, and increased mobility, and it may improve the circulation and lymphatic flow. The body, mind, and emotions all interact with the nervous system. It is possible that touching the skin sends messages, including reflex actions as the involuntary reaction of one part of the body to the stimulation of another part, to reduce the amount of stress hormones, which may lower blood pressure, slow breathing, improve digestion, and generate a sense of well-being. It is believed that massage also helps to release endorphins, the body’s natural pain relievers, and to activate neuropeptides, the intercellular messages within the nervous system. These link the skin to the nervous system and the entire body, including the immune system. These actions as a result of massage are thought to have tremendous benefits.

Indications for Massage


If a dog has a chronic musculoskeletal problem, it may develop secondary problems, which lead to postural and gait adaptations. In time, these may also become primary problems in themselves as a result of changes in the soft tissues, which lead to unprotected joints, possible damage to the joints, and a painful response.

Massage for the Competitive Dog

Proper massage applied to competitive dogs may help to establish or reestablish full tissue function. Massage may be employed during the training period for treatment and rehabilitation, and to enhance athletic performance. It may also help to prepare the dog for competition or exercise, and to reduce stress and aid relaxation. After hard exercise or competition, it aids recovery.

At an amateur level, training may sometimes be somewhat neglected, and massage can play a significant role in maintaining tissue pliability, in hopes of preventing injury. At the other end of the scale, top canine athletes are more likely to be overtrained, and massage can assist in recovery from fatigue. In this case, 2 hours should be allowed to elapse after competition before massage is started for maximum effects. Care must be exercised to not massage too deep and induce mechanical trauma, which may be detrimental to fatigued muscles.

Massage for Performance

To perform properly, the body must be able to adapt to the extra stresses placed on it. Requirements for excellence are power, agility, and coordination of the dog, and to attain this level of performance, the dog must cope with activity at the extremes of joint movement and muscle length. This places heavy demands on the strength and the endurance of the muscle, and the ability of the joints to move freely in all directions. The dog also needs freely mobile connective tissues. Inevitably, excess or repetitive stresses, or overwork, may increase the likelihood of other injuries, such as muscle strain. In all cases, this results in replacement of connective tissue with scar tissue, resulting in loss of power, flexibility, and movement in the tissues. Moreover, if the tissue is not rehabilitated before normal full activity is resumed, then it may never fully recover and return to normal limits. This in turn may overload the surrounding tissues, causing fatigue and hypertrophy of muscle groups.

Massage can be used to stretch and free this inelastic scar tissue and return tissue mobility to normal. It also helps to remodel and promote resorption of the scar and to reestablish full function of the tissues.

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Jul 8, 2016 | Posted by in SUGERY, ORTHOPEDICS & ANESTHESIA | Comments Off on Massage

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