Muscles work when a set of protein molecules composing them 'overlap' by being electro-chemically stimulated. These long chains slide past one another and the accumulated effect is a muscle contraction. Essential to the process are two things: nerve stimulation and minerals, particularly calcium (Ca).

The theory of trigger points involves the specific accumulation of Ca at certain points and the way nerve and muscle tissue react as a result. While still under investigation, the theory isn't just wild speculation. One chief researcher was the official physician to President John F. Kennedy, known to have severe back pain. Trigger point therapy was regarded, at least by him and the doctor, as effective in his case.

Finding a trigger point, a small area where the muscles are in this particular condition, is a matter of careful examination. Many believe that taut bands of muscles are an indicator and a hard nodule (a central locus or area) can be felt. One difficulty is that trigger points can often refer pain.

To 'refer pain' means to stimulate one area where damage may actually be present but have it felt elsewhere. Naturally that makes finding the actual trouble spot tricky. One way is to run a finger perpendicular to the muscle direction, then look for a twitch response. Pressing the muscle at the point that causes it to contract is thought to be a way of locating the trigger point.

Others have reported an increase in heat in the area near the trigger point. If there's higher chemical activity in an area of pain, this might be valid. Pain is often accompanied by inflammation, which can produce a small amount of heat.

Though the theory has its skeptics (which is healthy), and isn't taught in medical schools, studies suggest there's more to it than just wishful thinking. Once trained, therapists can regularly locate trigger points in independent trials. That suggests there is a factual basis that each is identifying.

The neurophysiology of muscular pain is still a hot area of research. But there are serious studies that tend to locate trigger points at the juncture of small, overstimulated muscle spindles. Think of a group of vines twisting around one another. Then imagine that at some point that 'rope' has a small knot other than at the ends. That's a visual metaphor for a trigger point.

One way to approach them as a massage therapist is to use the common technique of tapotement. This is a gentle to moderate tapping motion that is frequently part of Swedish or sports massage. Using the fingers or a small instrument the area is tapped, moving above and below the suspected problem. Sometimes elbows are employed for slightly greater force. Keep in mind, it's important to seek client feedback since excessive pressure can cause bruising.

The human body has over 650 muscles, more than 200 bones and uncounted connective tissue, tendons, ligaments and more tying them all together. Though the therapist doesn't have to memorize every single one, he or she has to be familiar - both intellectually and physically - with a great many of them.

Add to that the knowledge of physiology required - not just the names of parts but how they work and interact - and you have a formidable hurdle to overcome on the way to becoming a massage therapist. As if that weren't enough, the massage therapist has to understand and detect directly with the hands, arms and feet what is happening with a particular client in a particular session.

The therapist has to go beyond even this when specializing. There are a dozen different forms of massage - Swedish, Shiatsu, Deep Tissue and others. There are combinations of styles, such as sports massage.

Proper stance, pressure, alignment and much more is required in order to deliver a quality massage. To achieve that the massage therapist has to recognize which muscles are affected by what kind of activity. He or she has to know how to work them to remove knots, achieve relaxation, improve circulation and more.

A knowledge of possible injury during the session is necessary, as is recognizing when not to massage. Deep tissue techniques in particular can cause more problems than it solves. A client who comes in with pain may be just suffering from the usual ache that prompted the desire for a session in the first place. Or they may have a medical condition that means no session should be performed.

To do this hour after hour, day after day, without injuring his or her own body is a perpetual challenge of the practice. A therapist's body can also become sore from effort - the effort involved in the practice. Techniques are taught in massage schools to preserve thumbs, ease hands, shelter the back and knees - all parts easily stressed by an active therapy practice.

Then there is the proper equipment. Sometimes a simple mat, or even a towel-covered floor is enough. Other styles require a table that has to be judged properly. Chair or corporate massage requires a specially designed and built chair for clients. Recognizing quality is important, both for client safety and to avoid losing money on bad investments.

All those aren't simply business decisions, since they affect the effectiveness of the massage delivered. Poor equipment, lack of knowledge, poor technique can all make even the most skilled massage artisan a less than complete success.

That sums up to a considerable amount of theory and practical knowledge, and experience needed to be an effective massage therapist. And you thought, perhaps, that all they did was rub oil around?

Muscles of the type that respond to massage striated like the leg and back, rather than smooth like many organs are made of 'ratcheting' proteins. These molecules slide past one another when nerves are electro-chemically stimulated. The result is a contraction. But they can go 'too far' and become bunched, tense and knotted. Massage relaxes them.

Massage also improves circulation by freeing trapped blood, encouraging the movement of lymphatic fluid and bringing in fresh oxygen and nutrients. As the muscles refresh and relax, they lengthen, producing a pleasant sensation.

And that, after all, is the basic point. Massage feels good.

Apart from all the hard fact that a qualified massage therapist has to learn - anatomy and physiology, a half-dozen basic moves within one or more styles, proper stance, how to feel body conditions and more - their basic goal is to induce well-being. That well-being comes from relaxing muscles, relieving stress, restoring the body to a more optimal condition.

Along the way, and not coincidentally, the mind is relaxed, too.

Stress is a combined physical and emotional condition. Massage can work on both. By relaxing the body, providing a quiet hour of soothing physical work, mental tension can be relieved also. At the same time, being pampered is an excellent reward for enduring the 'slings and arrows' as Shakespeare put it.

There are, luckily for those seeking one, a dozen popular styles to accomplish that purpose.

The most common in the Western world is probably Swedish massage. The long, gliding, moderate pressure strokes are ideally suited to relax muscles and restore vigor. Shiatsu focuses more on specific areas with deeper pressure. Originally a Japanese style, it long ago moved into Western spas.

Mixed styles, such as sports massage, are now common, too. An eclectic blend of Swedish, Shiatsu and anything else that accomplishes the purpose, it's done in nearly every fitness club today. As a pre-event method of warming and relaxing muscles for optimum performance it's stellar. As a way of healing over-strained muscles and restoring health afterward it's equally helpful.

'Newer' innovations have entered the scene, such as the use of massage sticks, hot stone massage, fascia stretching or deep tissue work and others. 'Newer' is in quotes because these techniques are actually ancient, though in many cases they are only recently being incorporated into Western spas and massage clinics.

Hot stones are literally that - basalt stones that are heated and applied to various parts of the body, chiefly the back and legs. Massage sticks are smooth wooden instruments that can provide a pleasant aid to work certain areas. Deep tissue techniques work on very localized areas with firm pressure to relieve joints, release knots and other point problems.

But whatever the style preferred, and different ones are useful at different times, a massage fundamentally improves health, relaxes mind and body and provides a wonderful experience. That makes it both a fine science and a delightful art.

But even apart from the integrated practice, Thai massage has many healthful effects. A session in Thailand will often last as long as two hours and cost only a few dollars. From the time when monks practiced manual manipulation in a temple setting, it has sometimes entered seedy areas. But 4-star hotels in Thailand now offer the same style (though at a greatly elevated price).

Though like many Asian styles, it's sometimes accompanied by unfounded pseudo-science such as 'energy meridians', there's no doubt about the validity of the practice. Thai massage is safe, effective and produces a wonderfully relaxing result.

Traditional manipulation techniques are used to adjust the skeleton, increase flexibility and relieve muscular and joint tension. In many cases, the stretching movements incorporate elements of yoga.

Clients remain clothed, usually in a loose-fitting pajama-style pair of pants and shirt. Through gentle stretches the client achieves a state of readiness for the rest of the massage. Then the practitioner will apply gentle pressure with the hands and feet, eventually working her way over the entire body.

Because of the type of movements and hand pressure employed, this massage type is particularly suited to the elderly and those suffering from conditions that benefit from massage. There are no sharp jerks and no highly focused applications of pressure - just a smooth, relaxing flow of movements applied gradually.

While lying on a mat, rather than a massage table, the practitioner elevates the knees, applying a gentle stretch to the back and behind the thighs. The legs are lowered and the Thai masseuse will use toes and feet to gently apply pressure to various parts of the lower body, giving an overall sensation that relaxes and produces good circulation.

Oil is rarely used and the movements are rhythmic and regular. Working along the so-called Sen energy lines (similar to Chinese meridians), the practitioner covers the entire body. Sometimes a hot herbal compress will accompany the relaxing movements.

Many therapists will manipulate the fingers and toes, walk on the client's back and perform gentle arches of the spine. All this is done in a safe, pleasant way that results in a client who is re-energized at the end.

The modern form was developed in Sweden around the beginning of the 19th century, though the origin is disputed. Many attribute the usual techniques to Per Henrik Ling, a Swedish gymnastics instructor who developed the style for athletes. Others give credit to a Dutch-born physician by the name of Johann Metzger.

But whoever should get the credit for this innovation, the techniques that are now practiced are largely agreed on. By contrast to most Asian styles, Swedish massage uses long, firm strokes and gentle tapping. Asian styles emphasize more focused pressure on specific areas.

The result is improved circulation, as muscles are encouraged to release trapped blood. Joints are made limber and tense muscles relax under the gentle but firm pressure. This is achieved by a combination of five different traditional movements employed by the massage therapist.

Effleurage is a gliding stroke, a movement in which the masseuse or masseur uses long arm movements with the flat of the hand to apply gentle pressure over large areas. In this way, long muscles receive a full range of attention and blood flow is evened out.

Petrissage is a complementary technique which kneads selected areas, but still with a larger surface than in Shiatsu. Compression strokes are used in conjunction. Pressure is the ratio of force to area. As the area is increased, for a given force, the pressure is lowered. This makes Swedish petrissage less intense than Shiatsu.

Friction, applied at the correct level, warms the surface of the body, which stimulates good circulation. It also invariably accompanies the gentle pressure that causes muscles to relax.

Tapotement is the percussive tapping or light pounding traditionally associated with a massage. The technique has been seen in a hundred films and TV shows and it helps loosen muscles and provides a gentle stimulation.

Vibration is often used in concert with the other techniques. A rapid, small-movement, shaking can help limber joints and relieve stress. This differs from the small rocking movements used in other styles in which limbs are grasped and moved as a whole.

Often, a traditional Swedish massage will be carried out using oil or lotion. Some clients find the decreased friction that results pleasurable and the aromas can add to the experience. Some specialty oils that heat on contact are sometimes used, though they aren't part of the traditional technique.

Many forms of massage, such as sports massage, deep tissue massage and others use Swedish techniques as a starting foundation. It's usually carried out while the client wears minimal or no clothing, covered with a drape that's uncovered a section at a time.

Systematically proceeding through different sections of the body, the massage therapist provides an overall body massage that leaves the recipient feeling relaxed. The overall mood elevation that results is a commonly reported benefit.

Many of the techniques used then would be familiar today, since they are an eclectic mixture of Swedish, Shiatsu and other styles. Some basic movements are common across massage styles and across centuries.

Effleurage, for example, is a long gliding stroke applied with medium pressure. Usually done with a flat, horizontal hand using the palm and fingers, the masseur slides firmly over the surface, working the skin and muscle. On the return stroke, the therapist uses light contact along a different path. The hands remain relaxed and follow the natural contours of the back, chest, thigh and buttock - any part being worked.

Effleurage is rhythmic, utilizing increasing pressure that gradually stimulates more blood flow and relaxes tense muscles. During this phase of the session, skin and muscle are warmed, nutrient flow to the muscles is improved and toxins removed as the pressure creates an active area in the body.

Petrissage is next. This is a technique that involves kneading, focusing on more specific areas and going deeper into the muscle tissue. Here lymph fluid can be encouraged to flow well, blood flow is maximized and knotted muscles are worked. As such, the techniques work best on large muscle groups such as the chest, back and thigh. Still, smaller areas such as the forearms, shoulders and neck can definitely benefit from petrissage.

Finally, friction is useful when properly applied. Repeated, harsh rubbing over a specific spot will irritate anyone. But smooth, circular motion that glides but doesn't tug stimulates skin and muscle. The thumb and forefingers are great tools for sensing trigger points, finding knotted muscles and seek out lesions.

Here it's important to work with the client to get feedback about where there may be trouble spots. One client's back proved to be interesting terrain. Working large areas, a great deal of pressure and friction could be endured without discomfort. But nearer the center, just outside the line of the spine, the lightest pressure applied with the thumbs produced a feeling like an electric shock.

Each person is individual and the techniques will need to be adapted accordingly. Each sport uses slightly different muscles, or uses them in a different way. The result is different injuries, alternatives in muscle groups that tend to get stressed and varying rates of healing. Using friction, for example, to separate muscle fibers or loosen scar tissue, can be carried out vigorously for one, but needs to be approached cautiously for another.

Keep in mind that dedicated athletes tend to push themselves too hard. Don't contribute to the mindset by overdoing the effort. The purpose is to relax and heal, but excessive force can damage joints and muscle connections. Adopt the Hippocratic oath used by physicians 'First, do no harm'.

To get the full benefit, it's desirable to seek out a professional massage therapist. But in the meantime, or for those smaller aches and pains, nearly anyone can adopt some of the methods used.

Have the recipient lie down on a mat or soft carpet. A massage table is handy, but not usually among the standard items of furniture in the average home. Have him or her take a few deep breaths, exhaling well to try to relax the whole body.

It may help to place a rolled towel briefly under the body at the top of the back, just below the base of the neck. This helps stretch out muscles which are tensed, prior to working them.

Now, positioned above the person, cradle the head with one hand, turning it slightly in one direction. Knead the chest muscles first. These, paradoxically, are often one of the primary culprits. If they're tight, they can cause the back muscles to tense, pulling the neck muscles with them.

Then work your way up, rubbing the trapezius at the top of the back, then onto the other muscles in the neck. The trapezius is one large muscle group - the top portion for part of the neck system, which fan out into large triangles on both sides of the spine.

Then, switch hands, turn the head slightly the other direction, and repeat.

Making small circles using the tips of the fingers, work the other neck muscles, then slide the fingers down the length of the muscle to the middle of the back and up again.

Turn the recipient over and repeat the procedure in reverse, starting with the base of the skull. Work down the trapezius pair, then over to the chest muscles. Sometimes a pillow under the chest will help create elevation that both stretches the neck and provides room to work. Move the head side to side very gently and stretch just ever so slightly.

Long, moderately firm, gliding strokes are ideal for this type of massage. Be prepared to go slowly and cover a much wider area than just the neck, since the source of the problem is often away from the spine and base of the skull.

Shiatsu differs from traditional Western (typically Swedish) massage in its emphasis on focused pressure, rather than the long strokes of Swedish massage. In Shiatsu, the fingers and palms apply pressure to specific sections of the body, concentrating on one part at a time. Eventually, the whole of the body can be covered, but a good Shiatsu will take a long time to complete.

Though, as with many forms of massage therapy, the theory is dubious - emphasizing 'energy' points, 'imbalances' and so forth for which there is no scientific evidence - there's no question that Shiatsu has a healing effect. A good Shiatsu practitioner can make a client feel relaxed, relieved of stress and full of genuine energy.

The way this is achieved is sound enough. The skilled Shiatsu massage therapist detects stiffness and other muscle and joint problems, then applies pressure to those areas. Experience is required to do it correctly, since excessive pressure can do more harm than good. But with training, most therapists will achieve this level.

There are several variations on the practice, most coming under the heading of acupressure. Jin Shin Jyutsu, for example, is based on the theory that pressure can change the direction of energy flowing through the body. Here again the theory is without foundation, but the practice has real benefits. Using a light touch, held for several minutes, knotted muscles can be stimulated to release.

When a muscle tenses, it can go too far. It can tense up to the point of causing pain. This is a form of 'protection' in which the muscle proteins 'clamp together' to reduce additional movement that would cause further injury. Loosening that 'knot' helps the muscle regain a healthful state.

Focusing pressure, using the thumb, finger tips and palms on specific areas can loosen stiff muscles, limber joints and stimulate good circulation. All those have real, positive health effects.

There is ample evidence to show that increased blood flow, decreased muscle tension and proper joint movement have actual health benefits. Those suffering from arthritis, tendonitis and even just ordinary muscle ache commonly report feeling better after a good Shiatsu session. Nothing could be clearer proof than that.

Hot stone massage uses smooth, heated stones (hence the name, not surprisingly) that are applied to the client's various body parts, usually starting with the back. The rocks are often basalt, a black volcanic rock. They're used because they absorb and retain heat well, making re-heating less frequently required. But to be of use they have to conduct heat well, too, since the heat must go into the client. Basalt covers all those needs.

The stones are sanitized, heated and applied to an area where they have a relaxing effect on muscles. The therapist tests them first, usually simply by holding one in order to ensure the proper temperature - between 120F-150F (49C-65C). For comparison, water boils at 220F/100C.

A variety of massage techniques can accompany the application of the stones, but Swedish is among the most common. The smooth, firm, long and gliding strokes complement well the relaxing effect of the hot rocks on the body. Stones can be applied along the line of the spine, but more commonly along the muscles beside it. The lower back (erector spinae), the middle back (latissimus dorsi) and the upper back (trapezius) are typical spots as well.

The stones are small and the pressure applied by them is comfortable but doesn't have any particular therapeutic effect. The major work is done simply by the heat. Though there are, as usual, some mystics in the field who ascribe magical powers to stones of different types or ascribe application to certain points as having special effects.

Hot stone massage sessions are frequently much more expensive, in part because of the added preparation required. The largest part of the difference is simply demand for it. It's currently a very popular technique and, as such, will demand a higher price. Whether the results are worth the added cost is an individual decision.

One variation involves using the stones in the therapist's hand to apply heat to various areas and add pressure. The warmth is pleasant, but the added pressure is typically unnecessary. Any professional masseuse or masseur can apply more pressure than is desired without artificial aids.

Another variation alternates the use of hot basalt stones with cool marble stones, which creates a delightful experience for the recipient. Whether this should be called massage is beside the point, since the basic purpose of the experience is to create a pleasant, relaxing effect for the client.

'Lomi' is the Hawaiian word for 'rub', and hence Lomilomi ('masseur' or 'masseuse') has come to mean the practice of massage originating in this tropical island nation. It has a number of interesting differences from other Asian-influenced massage styles.

Lomilomi involves use of the elbows and knees, along with the palms and fingers. Even the forearm sees action and sometimes sticks or stones are made use of as supplements. The client of Lomilomi gets the full treatment. But far from being nothing but an eclectic mixture of techniques applied without thought, practitioners in Hawaii are required to pass a written test that encompasses anatomy, physiology and massage theory.

Like many massage styles Lomilomi can be (and traditionally is) part of a larger healing routine, including prayer, meditation and diet. As a stand-alone massage technique it is still superb. Originally practiced by native healers, even believed to affect digestion and restore harmony within the family, it has tangible benefits. It was often a useful adjunct to those who practiced Hawaiian-style martial arts.

Though, like many Asian-style therapies, it is based on unfounded 'tribal wisdom' about 'energy' (in this case called 'Huna'), Hawaiian-style massage has definite health benefits.

Huna theory, on which the practice is based, is a complex set of beliefs about the relation between the spiritual and physical, according to which energy gets blocked in the joints. The style evolved to 'unblock' this 'energy'. While clients may see a practitioner perform a traditional Hawaiian dance around the table during the treatment, they'll appreciate the total effect.

Lomilomi massage involves applying continuous, flowing strokes to relax the muscles. Red clay or Hawaiian salt is sometimes used to cleanse and prepare the client's body for the therapy. Some sessions involve time in a steam hut or plunges into the ocean to stimulate circulation.

Gentle stretches and rotation of limbs results in a relaxed body and a peaceful spirit. Even the practitioner's humming can help induce a pleasant frame of mind. Some recipients may not enjoy laying directly on a vinyl table, as Lomilomi uses no sheet underneath, and just a small towel on top. Heaters are sometimes used to maintain a comfortable air temperature, but this is rarely necessary in Hawaii itself.

But this eases the ability of the masseuse to apply full-body strokes in one smooth motion. Many of these involve lifting and applying pressure under the body during the procedure, which makes for an unusual and delightful experience. The rhythm with which the movements proceed will vary widely, since Lomilomi practice is very individual and intuitive. The formality of other styles is largely absent here.

Occasionally, Lomilomi will actually be carried out by two practitioners at the same time, where it becomes a double-treat.