Electricity and Magnetism
Electromagnetism was first discovered in the 1800s by the English physicist Michael Faraday, who determined that a magnetic field could be generated by running an electric current through a wire coil. Conversely, a changing magnetic field can generate an electric voltage; the magnetic field must change to have any electrical effect (hence, the term pulsating electromagnetic field therapy, which generates rising and falling levels of a magnetic field.)

The biological effects of pulsating electromagnetic fields are hypothesized to be due to electrical rather than magnetic forces. Magnetism generates a voltage in tissue according to the equation:
V = n x a x dB/dt

V = Voltage

n = number of turns in the electromagnetic coil

a = area of the loop

dB/dt = The rate of change of magnetic field with respect to time, with B representing the strength of the magnetic field (in Teslas). For example, if B goes from zero to 1 Tesla in 1 millisecond, then dB/dt = 1000 Teslas/sec.

Based on this equation, a static magnetic field cannot generate an electrical voltage, as the dB/dt component of the equation, is zero, as is the voltage induced by the field. Thus, any effects of a static magnetic field on tissue cannot be electrical in nature.

Pulsating Electromagnetic Field Therapy

Extracellular matrix synthesis and repair are subject to regulation both by chemical agents (such as cytokines and growth factors) and physical agents, principally mechanical and electrical stimuli. The precise nature of such electromechanical signals is not known, however. In bone, mechanical and electrical signals may regulate the synthesis of extracellular matrix by stimulating signaling pathways at the cell membrane.6,7 In soft tissue, alternating current electrical fields induce a redistribution of integral cell membrane proteins which, hypothetically, could initiate signal transduction cascades and cause a reorganization of cytoskeletal structures. 8 However, the hypothesis that electrical signals may be responsible for information transfer in or to cells has neither been proved nor disproved.

There is ample evidence that electrical activity exists in the body at all times. For example, electrical currents can be measured in the beating heart and are also generated in the production of bone. Endogenous electrical current densities produced by mechanical loading of bone under physiologic conditions approximate 1 Hz and 0.1 - 1.0 microA/cm2 .9 Thus, it is theorized that application of an appropriate electrical current, either directly through wires or indirectly through induction by a magnetic field, may affect tissues in several ways. The word appropriate in the preceding sentence is important since cells and tissues respond to a variety of electrical signal configurations in ways that suggest a degree of specificity for both the tissue affected and the signal itself.

The most widely studied application of electromagnetic field therapy in human medicine is in fracture therapy. Although the mechanisms remain undetermined, several studies report that electrical fields generated by pulsating electromagnetic field therapy stimulate biologic processes pertinent to osteogenesis10,11,12 and bone graft incorporation. 13,14 This form of therapy is approved for the treatment of delayed and non-union fractures in humans in the U.S. by the United States Food and Drug Administration. Effectiveness of the treatment is supported by at least two double-blind studies.15,16 Pulsating electromagnetic field therapy, however, delays the healing of fresh experimentally induced fractures in rabbits.17

Pulsating electromagnetic field therapy has also been evaluated in the treatment of soft tissue injuries, with the results of some studies providing evidence that this form of therapy may be of value in promoting healing of chronic wounds (such as bedsores)18 , in neuronal regeneration,19,20 and in many other soft tissue injuries.21,22 results of a recent study in an experimental Achilles tendinitis model in rats indicated that there was an initial decrease in water content in injured tendons treated with pulsating electromagnetic field therapy but that all treated groups were equal to controls by 14 days.23The limited value of this form of therapy in the treatment of tendon injuries may be due in part to the lack of significant electrical activity in tendons, activity that could be altered by a pulsating electromagnetic field.

In contrast, a number of investigators have been unable to show any effect of low-level electromagnetic fields on tissue healing. One study, for example, failed to identify any beneficial effect of applying a magnetic field to a non-healing fracture24 and concluded that the long periods of immobilization and inactivity required for the application of the magnetic field therapy were just as likely to be responsible for tissue healing.

Criticisms of pulsating electromagnetic field studies include: some of the studies are poorly designed; independent trials have not been conducted to confirm positive results; and the electrical fields induced by the machines are several orders of magnitude lower than are required to alter the naturally occurring electrical fields that exist across biological membranes.25 Even proponents of the therapy concede that much work needs to be done to optimize such variables as signal configuration and duration of treatment before pulsating electromagnetic field therapy can be generally recommended.26

Static Magnetic Field Therapy

Magnetic devices that radiate an unchanging magnetic field are available in a variety of configurations such as pads, bandages, and even magnetic mattresses. Scientific studies do not support claims of efficacy. Furthermore, a mechanism of action by which such devices might exert these effects remains elusive. Because static magnetic fields do not change, there can be no electrical effect. Hypotheses for an effect of a static field include influencing the electronic spin rate states of chemical reaction intermediates27,28 and influencing cyclical changes in the physical state(s) of water.29 Importantly, neither of these proposed effects has been demonstrated in biological systems under physiological condition.30

In spite of a lack of demonstrable mechanism of action, proponents of applying static magnetic field therapy to injured or painful tissues generally attribute their alleged effects to an increase in local blood circulation. Unfortunately, the scientific evidence in supporting this hypothesis is tenuous at best.

Blood, like all tissues, contains electrically charged ions. A physics principle known as Faraday's Law states that a magnetic field will exert a force on a moving ionic current. Furthermore, an extension of Faraday's law called the Hall effect states that when a magnetic field is placed perpendicular to the direction of flow of an electric current, it will tend to deflect and separate the charged ions. While the deflection of ions will be in opposite directions depending on the magnetic pole encountered and the charge of the ion, this force is not based on the attraction or repulsion of like and unlike charges.

The Hall effect implies that when a magnet is placed over flowing blood in which ionic charges (such as Na+ and Cl-) exist, some force will be exerted on the ions. Furthermore, the separation of ionic charges will produce an electromotive force, which is a voltage between points in a circuit. In theory, this produces a very small amount of heat. These physical effects, which do exist, provide the basis for a quasi-scientific theory to account for the purported effects of static magnetic field therapy. For example:

When a magnetic field with a series of alternating North and South poles is placed over a blood vessel, the influence of the field will cause positive and negative ions (for example, Na+ and Cl-) to bounce back and forth between the sides of the vessel, creating flow currents in the moving blood not unlike those in a river. The combination of the electromotive force, altered ionic pattern, and the currents causes blood vessel dilation with a corresponding increase in blood flow. 31

The problem with using Faraday's law and the Hall effect to explain the purported effects of static magnetic pads is that the magnitude of that force applied by the field is infinitesimally small. Two facts account for the lack of effect. First, the magnetic field applied to the tissue is extremely weak. Second, the flow of the ionic current (i.e., the blood) is extremely slow, especially when compared to the flow of electric current. However, it is possible to estimate the forces applied to flowing blood by a weak magnetic fieldas long as the strength of the magnetic field applied, the velocity of the flowing blood, and the number of the ions in the blood are known.

Magnetic field strength is measured in one of two units: 1 Tesla = 104 Gauss. The magnetic field strength of a Norfield's MAGNETIChockwrapTM(for horses) measured at California Institute of Technology had a field strength of 270 Gauss at the level of the pad and 1 Gauss at a distance of 1 cm from the pad. Tissues purportedly affected by the pads lie at least 1 cm away from them; 1 Gauss is approximately the magnetic field strength of the earth.32 Promotional information for Bioflex pads asserts an "independent laboratory" has measured the field strength of their pads at 350 Gauss and that "optimum" field strength for the purported healing effects is less than 500 Gauss.33 Regardless, these are very weak magnetic fields.

Considering the applied magnetic field at 250 Gauss (0.025 Tesla) and the velocity of blood flow v as 1 cm/sec (0.01 m/sec), the electric field to which an ion in the blood is exposed can be calculated as:

E = v x B = 2.5 x 10-4 Volts/meter/sec

Hence, the change in electric potential (a psuedo-Hall effect) across a 1 mm diameter blood vessel can be estimated at a minuscule 2.5 x 10-7 Volts.

Ions of opposing charges will move in opposite directions when moving through a static magnetic field. The separation of charges, known as the drift velocity, can also be calculated. In the case of Na+ and Cl- ions in flowing blood under the influence of a 250 Gauss magnetic field, the increased separation of the positive sodium and the negative chloride ions will be about 0.2 Angstroms per second, or about 1/10 the diameter of an atom. This can be compared with the random drift distance in one second that results from the thermal agitation imparted by the heat of the horse's body of about 0.25 mm/sec. Stated in another fashion, the ions will travel farther from thermal agitation than from the 250 Gauss magneto-electrical field drift by a factor of about 10 million.34

Any magnetic forces generated by a static field affecting fluid movement in blood vessels would have to overcome both the normal, pressure-driven turbulent flow of blood propelled by the heart and the normal thermal-induced Brownian movement of the particles suspended in the blood. Given the strong physical forces that already exist in a blood vessel, any physical forces generated by a static magnetic field on flowing blood, particularly those as weak as those associated with therapeutic magnetic pads, are extremely unlikely to have a biological effect.

Magnetic Pad Design

At least one manufacturer of magnetic pads (Magnaflex/BioflexTM) asserts that the effect of charge separation can be increased by alternating north and south magnetic poles. Alternating magnetic poles are most commonly seen in refrigerator magnets. By alternating the magnetic poles, an increased magnetic gradient is created, which increases the ability of the magnets to stick to the refrigerator. Paradoxically, alternating poles decrease the magnetic field strength of the magnet because the fields tend to cancel each other out as they extend from the magnet. Thus, while alternating poles would exert opposite forces on ions flowing through the magnetic field, the decrease in magnetic field strength would lessen any potential influence of the magnetic field on the target ions. Nor does there appear to be any consensus in the industry as to the ideal design for the pads. In fact, a competing manufacturer asserts that, "Leading scientists agree that unipolar magnets are superior to bi-polar,"35 although neither the scientists nor the supporting research are identified.

Further proprietary design information regarding at least one commercial source of magnetic pads (BioflexTM pads) would also appear to be irrelevant regarding biologic effects. Promotional information for the pads indicates that the "concentric circle" arrangement of the pads increases the likelihood that the magnetic field would be applied perpendicular to flowing blood, thereby maximizing the Hall effects. In fact, because blood vessels run randomly throughout the three dimensions of any tissue, there can be no "preferred" arrangement of the magnetic field that would favor its perpendicular orientation to the flow of blood.

Studies on Static Magnetic Fields and Blood Flow
A number of studies have investigated the effects of static magnetic fields on blood flow. Studies commissioned by the makers of one type of magnetic pad showed that exposure of a highly concentrated saline solution in a glass capillary tube increased the flow of the solution. This study has been often cited by manufacturers of static magnetic devices as evidence that magnetic field therapy can potentially affect the circulation of blood. Although the mechanism for the increase in saline flow is not apparent, it certainly could not have been related to any dilatory effect on the walls of the glass capillary tube. The investigator who performed the study concluded that the results of the experiments performed using highly concentrated saline in a glass tube should not be extrapolated to effects that would be expected with flowing blood.36

A second study evaluated the effects of the pads in the distal limbs of horses using nuclear scintigraphy, a technique that is useful in identifying areas of blood vessel dilation and inflammation. That study concluded that, "Scintigraphy was performed in the vascular, soft tissue, and bone phase using a cross over trial to demonstrate increased blood flow and metabolic activity as a result of the local application of a permanent magnetic pad on the equine metacarpus. A highly significant increase was evident in the three phases."37 The results of this study have been used repeatedly to suggest that magnetic pads promote blood circulation to the areas under the pads.

This study, which is apparently the only one to state that a static magnetic field affects blood circulation, is open to criticism. The experimental model, which compared the results of scans on one "treated" limb vs. the non-treated limb is inherently inaccurate, as one forelimb cannot be used as a control for the other in scintigraphic studies (each limb should be used as its own control). Furthermore, the design of the study was flawed, as a bandage and magnetic pad were applied to one limb while a bandage only was applied to the other. A more appropriate control would have been a bandage and a demagnetized pad. The radioisotope chosen for the study was not appropriate to determine blood circulation accurately. Finally, the study measured absolute scintigraphic counts, when the use of relative perfusion ratios would have been more appropriate.38

Numerous other studies have failed to show any effect of magnetic fields on blood circulation. For instance, no effect of dental magnets on the circulation of blood in the cheek could be demonstrated.39 Scintigraphic evaluation of blood flow in mice exposed to two strengths of pulsating electromagnetic field force failed to demonstrate any circulatory effects.40 A study on the circulatory effects of a magnetic foil was unable to show any effect in the skin of human forearms41 and application of a magnetic foil to healing wounds in rats showed no significant effects.42 A study in horses showed that application of a magnetic pad over the tendon region for 24 hours showed no evidence of temperature increase in treated limbs vs. placebo controlled limbs, using thermographic measurements as an indirect assessment of blood circulation to the area.43

As a more practical matter, if a magnet caused local increases in circulation, one would expect the area under the magnet to feel warm or become red as a result. Such an effect is not reported when magnets are held in the hand. Furthermore, one would expect any circulatory effects produced by very weak magnetic fields to be magnified in stronger magnetic fields. However, no circulatory effects have ever been reported in magnetic resonance imaging machines, in which the magnetic forces generated are two to four orders of magnitude greater than those produced by therapeutic magnetic pads. In studies of humans exposed to magnetic fields up to 1 Tesla (10,000 Gauss) there was no evidence of alterations in local blood flow at the skin of the thumb or at the forearm.44 Even a 10 Tesla magnetic field is predicted to change the vascular pressure in a model of human vasculature by less than 0.2%, and experimental results of the effects of strong magnetic fields on concentrated saline solutions are in general agreement with these predictions.45

Based on the available scientific data, one must conclude that if there is an effect of static magnetic fields on blood circulation, there is no known biological mechanism by which that effect is generated. One may also postulate that the boots, blankets, and bandages in which the magnets are sewn have some sort of a thermal effect that is independent of the magnetic field (and could be duplicated with any form of bandaging).

Magnetic Fields and Pain Relief

Both static and pulsating electromagnetic field therapy have also been promoted as being beneficial for the relief of pain. As with other proposed effects, there is no known mechanism of action by which application of a magnetic field produces biological effects. If they are effective in the relief of pain, it is unlikely that the effect is related to a reduction in nerve conductivity; the field required to produce a 10% reduction in nerve conductivity is roughly 24 Tesla.46

Studies evaluating the effects of pulsating electromagnetic fields in the relief of pain have shown conflicting results. Pulsating electromagnetic field therapy has reportedly provided pain relief in the treatment of osteoarthritis of the human knee and cervical spine,47,48 in the treatment of persistent neck pain,49 and in the treatment of women with chronic refractory pelvic pain.50 However, electromagnetic therapy showed no benefit in the relief of pain due to shoulder arthritis51, and a 1994 summary of published trials of non-medicinal and noninvasive therapies for hip and knee osteoarthritis concluded that there were insufficient data available to draw any conclusions on the efficacy of the therapy.52 Paradoxically, another study in humans showed that magnetic treatment actually induced hyperalgesia in a tooth pain model.53

Pads that apply a static magnetic field are also promoted as having pain-relieving effects. Poorly controlled studies from the Japanese literature suggest that static magnetic devices were highly effective in alleviating subjective symptoms such as neck, shoulder, and other muscular pain.54,55 One controlled, double-blind pilot study suggested that magnetic pads were effective in the relief of myofascial or arthritic-like pain in postpolio syndrome,56 although every patient in the study, whether being treated with a placebo or a magnet, showed relief from pain. However, other studies have concluded that a magnetic foil offered no advantage over plain insoles in the treatment of pain of the human heel57 and that a magnetic necklace had no effect on neck and shoulder pain.58 It has also been suggested that there is a strong placebo effect at work in the perception of pain relief offered by static Magnetic devices.59

Clinical Use of Magnetic Fields in Veterinary Medicine

Magnetic and electromagnetic devices appear not to be used on small animals. However, the devices are widely advertised in magazines targeted at horse owners. Pulsating electromagnetic field therapy is typically applied to horses with boots or blankets. Some of the variables of the magnetic field generated (such as the amplitude and frequency of the signal) can be controlled using this form of magnetic therapy. However, changes in these variables appear to affect different tissues in different ways, and those ways are not well defined, making selection of ideal field strength of the therapy problematic.

The other way to apply a magnetic field to a horse is by attaching a magnetic pad. This form of therapy generates a continuous, static magnetic influence on the targeted tissue; however, the magnetic field cannot be modulated. The principle advantage of this form of magnetic therapy is that it is relatively inexpensive (compared to the cost of the machines) and easy to apply; the disadvantage is that as yet there is no scientific evidence of an effect.

The absence of a plausible scientific theory for a mechanism of action should never override reliable strong clinical evidence of an effect. For example, the mechanism of aspirin was not known for many years, although the drug was clinically effective. However, there appear to be no published scientific studies available that demonstrate that any form of magnetic field therapy is valuable in the treatment of disease conditions of the horse.

Daily electromagnetic therapy did increase the concentration of blood vessels in surgically created defects of equine superficial digital flexor tendon, but the maturation of the repair tissue and the transformation of collagen type (two essential components in the healing process of tendon) actually were delayed by the treatment in tendon samples collected at 8 to 12 weeks after surgery.60 No benefit could be demonstrated in the healing of freshly created bone injuries treated with pulsating electromagnetic field therapy when compared to untreated control limbs, 61 although another study did suggest an increase in bone activity under pulsating electromagnetic field treatment when holes were drilled in horse cannon bones.62 Topical treatment with a pulsed electromagnetic field showed little effect on metabolism of normal horse bone in another study.63 Unfortunately, the principle application of pulsating electromagnetic field therapy in people, for delayed and non-union fractures, is of little apparent use in horses.

Callanetics

Where does callanetics come from ?
American born Callan Pinckney developed the original programme a few decades ago after training with Lotte Berk (now in her mid 80s). Lotte Berk was a famous dancer and after a severe back injury devised an exercise programme that kept her and thousands of others fit, supple and strong into old age.

Callan Pinckney was born with scoliosis and during 10 years of backpacking throughout the world developed further back and knee damage. When she found the programme to be an incredible success on herself, she started teaching other people. She has taught thousands of people since then, all with great results. Over the years Callanetics has been further developed and refined, and after careful research more and more variations to the original programme are introduced on a continuous basis.

Is callanetics safe ?
It is so safe that even eighty year olds can do these exercises.Originally developed for bad backs, Callanetics uses small, delicate movements consistently applied. Muscle groups are isolated and worked at whilst the rest of the body is completely relaxed. There is no sudden jerking or any hard impact, which can cause harm to the body.

Is dieting part of the callanetics programme ?
When doing Callanetics regularly, a person can wear clothing two sizes smaller without shedding a kilo. Dieting is, therefore, not part of the programme. However, if you lose 5 kg, it will look as if you had lost 10 kg.

Is callanetics easy ?
The exercises are hard work - at first. But they make you feel spectacular! And one hour of Callanetics is equal to 24 hours of aerobic dancing in terms of tightening, pulling up, and visible results.

Do you always have to do a whole hour of the exercises in one session ?
If you do the exercises at home, the answer is no. You can break an hour of exercises into 15 minute segments with the same dramatic results.

Will it really work ?
Within a few hours of Callanetics workouts you will have the answer.

What are the benefits of callanetics ?
Exercise, in general, promises strength, endurance and flexibility. The Callanetics programme has nine additional benefits, ie:

coordination
balance
comprehensive body awareness
body control
discipline
speed
physical and mental relaxation
builds stamina
decreases appetite