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Historically,
several systems of manual therapy have attempted to define themselves
as neurophysiological systems of health care, or manual therapeutic
approaches to neurological homeostatsis. These systems have included
chiropractic (Palmer) and naprapathy (Smith), and also include several
categories of massage therapy including PNF, NMT, and what is generally
described as medical massage. Also included in the list of manual
therapies that can be considered to facilitate neurophysiological
responses in the human body would be the varied techniques of
acupuncture and acupressure. This article attempts to explain the
common neurological mechanisms that are shared by the various systems
of manual therapy, the mechanisms by which they work, the similarities
between these systems, and the unifying physiological principles that
explain why manual therapies effect significant neurological changes in
the body. For the purposes of this article manual therapy is defined as
a hands on therapy, whether massage or manipulation, or any therapy
that primarily has as its mode of effect direct stimulation of the
skin, and it’s biological sensors, components of the peripheral nervous
system associated with the soft and connective tissue structures of the
body, including acupuncture and hydrotherapy.
Education in the
manual and massage therapies commonly begins and ends with muscles,
tendons, and bones, and in most cases does not venture much beyond
these anatomical area’s. The study of the central and peripheral
nervous system including mechanoreceptors, nerve endings, nerve roots,
branches, and trunks, the spinal cord and the brain and its component
parts is not a standard component of general massage education.
However, as manual and massage therapy develop into more advanced
medical massage and medical manual therapy, a foundational knowledge of
the central and peripheral nervous system is essential.
Unfortunately,
manual and massage therapy’s have been collectively labeled as
“unscientific”, in part because of fanciful claims and erroneous
conclusions made by early proponents and practitioners, and
additionally because of a lack of understanding of the neurological
mechanisms by which these manual systems effect physiological change in
the human body. This has also resulted from a general lack of interest
on the part of the medical and scientific community to investigate the
relationship between medical massage therapy and therapeutic responses
in the body. Additionally, there has also been a lack of creative
imagination on the part of the scientific community in both
comprehending the relationship between contemporary scientific
discoveries in neurology, massage, and manual therapy, and in applying
these discoveries to manual therapy methodologies, techniques, and
protocols.
Substantial research has been concluded and
categorized that relates the physiological function of the peripheral
and central nervous systems to the techniques of massage and manual
therapy. This research includes investigations into the effects of
manual therapy on peripheral neurobiological sensors in connective
tissue, mechanoreceptors, and proprioceptive responses reported by
mechanoreceptors and mediated and controlled by the brain. Older models
of understanding that attempt to define manual and massage therapy as
strictly a “muscle and joint” art of compression and manipulation are
outdated concepts that only impede our full understanding of the far
more physiological and neurological global effects of manual and
massage therapy and serve only to retard the advancement of these
therapies as equal and valid medical practices.
It has been
necessary for contemporary medicine (allopathic) to denigrate and to
categorize manual therapy as unscientific and as a primitive and
simplistic method of therapy and to relegate manual therapy to the
fringes of health care. This has been necessary because medicine has
needed a scapegoat by which to compare and elevate it’s self, and
because of medicines investment in surgery and chemotherapies. However,
a health care system that claims to be based on the principles of
scientific research should understand that eventually that same science
and research will lead to a complete understanding of the important
mechanisms of manual therapy and its effect on human physiology.
Research
related to the brain has spanned centuries but contemporary
neuroscience has had a variety of highly effective methods by which to
study the brain. These research techniques have include the ECG and
brain mapping techniques, as well as X-ray Computed Tomography (XCT),
Magnetic Resonance Imaging (MRI), and Positron Emission Tomography
(PET). With these tools it is now possible to observe minute brain
function and activity, even on the molecular level. For example, PET
and functional MRI now allow us to monitor brain activity by observing
the brains metabolism as it absorbs oxygen and glucose, a measurement
of brain activity.
This imaging power has opened wide the doors
of brain related research and “accidentally” allowed investigations
into unintentional areas of research, including the effects of manual
therapy on neurological and humoral functions in the brain and nervous
system. Research in the fields of acupuncture, exercise, and manual
therapy techniques related to endorphin release suggested that these
stimuli facilitated activity in the cortex of the brain and the humoral
functions of the hypothalamus and pituitary glands. It can now be
stated as fact that manual therapy stimulates brain cortical
activities, which in turn activates other brain centers from the upper
to the lower (deepest) levels of brain function, including the more
survival related brain areas that control essential life maintaining
physiological functions.
As far back as the early 1900’s
neuroscience has understood the concept of cortical localization in the
brain and various activities of the body such as seeing, hearing, and
feeling sensation. In the 1920’s and 1930’s Penfield and associates
described these relationships and created a map called the homunculus.
You probably saw this brain map in a high school science book. (The
funny little man laid across the top of the brain?) Cortical
localization is an important concept for manual therapists because it
leads to an understanding of the relationship of intentional manual
therapy, transmission of impulses via the peripheral nervous system to
the central nervous system, and initiation of cortical responses.
Cortical stimulation is the stepping stone to the initiation of other
activities and responses in the brain including humoral functions of
the hypothalamus.
The neuroanatomy and neurophysiology of the
brain is a complex and difficult subject, and understanding the
mechanisms by which the brain monitors and mediates the body and its
functions is equally complex and difficult. As previously mentioned,
neuroanatomy and neurophysiology are relatively new subjects for the
manual or massage therapist. Much of what is currently taught in
massage schools and massage textbooks that is related to the peripheral
and central nervous system is incorrect, including popular concepts
describing proprioceptors, the golgi tendon organ, and stretch receptor
function and peripheral control over muscle/tendon tension. The so
called “tendon reflexes” or “reflex mechanisms of massage”. The
information provided in popular massage textbooks, massage articles,
and approaches to therapy such as PNF, CMT, and NMT are based on
erroneous and incorrect theories of nervous system behavior. Other
popular and commonly practiced massage techniques including massage
trigger point theory and myofascial release are equally inaccurate
understandings of the function of the peripheral and central nervous
systems functions and activities.
These erroneous non
physiological “reflexes” are based on old models of understanding that
date as far back in the history of scientific research as 70 years ago!
This model of understanding, which is still dogmatically taught to
massage therapists, is a simplistic theoretical model which has been
left behind by contemporary research and largely discredited as
artifacts of improper research technique. PNF, golgi tendon organ, and
stretch receptor theory are erroneous because it is the brain and the
central nervous system, not peripheral mechanoreceptors that controls
connective tissue responses. The receptors just report the information,
the brain determines, based on the totally of the “experience” what
signals to send that will mediate function and reaction. PNF activities
are so limited in time and brain learning experience that they have
little or no effect in “reprogramming” neurological activity, and the
“therapeutic” movements are most likely just viewed by the brain as
“background noise”. Golgi tendon and stretch receptor theories do not
explain how we are able to lift a very heavy weight, or hang from a
cliff by our finger tips without the GTO’s and stretch receptors
causing a relaxation in the working muscles and joint that would cause
a loss of control. Or how professional athletes keep on pushing the
boundaries of human endeavor without “interference” from the “tendon
reflexes”. Excessively deep tissue technique that provokes pain and
tissue damage stimulates the pain receptors in the tissue and has been
found by Melzack and Wall to both increase patient pain and to retard
patient recovery. Therapists that practice these deep tissue, pain
provoking techniques, including myofasical release, typically pride
themselves on the pain that they provoke and view the negative symptoms
of pain, nausea, sweating, dizziness, hypotension, and disorientation
as a positive clinical result, when in fact these symptoms are evidence
that the therapist is simply making the patient sicker, by stimulating
a supra segmental sympathetic nervous system response.
According
to the stretch receptor theory if I stub my toe on the way to the
bathroom (suddenly stretching the quadriceps) a reflex reaction will
occur that would contract the overstretched muscles, resulting in the
leg kicking forward. In other words driving my toe further into the
object that I tripped over! Does this actually happen in real life? No,
and it doesn’t because the cortex of the brain which “knows” and
“understands” the totality of what just occurred won’t let it happen.
What about when you are rock climbing or power lifting, or any of
hundreds of high performance activities that are performed by
professional and recreational athletes? Just when you need maximum
muscle contraction, do the bodies stretch receptors and golgi tendon
organs let you down? Not in real life. These reflexes are just
reporting mechanisms and are not controlling mechanisms. The control
occurs in the CNS. In other words, the conclusions that massage
therapists have come to that have led to the development of massage
theories, techniques and systems of massage are based on non
physiological understandings of muscle and tendon function. They don’t
actually happen, the techniques based on them don’t actually work, nor
can they be considered medical massage therapy.
The author has
been teaching and writing about these issues since 1980 and this is the
sixth recently published article that this author has written on this
topic alone. Articles supporting the reflex theories and non
physiological massage techniques continue to appear in massage
textbooks and periodicals as the writers continue to parrot the old
theories and dogmatic approaches to massage. Why does this situation
and material persist? Largely because the authors and teachers of these
theories and techniques themselves do not understand the real and
actual physiological processes of the body related to neuromuscular
responses, and have failed to read and to comprehend the more
contemporary literature on the subject. As one of my teachers said to
me” You cannot teach what you do not know, and you cannot give a gift
that you do not possess.”
There is “wisdom” within the body and
there is also an organized system of function. This system includes two
mechanisms that sense whether a stimulus or event is good or bad for
the body. Good stimulation proceeds from the peripheral biological
sensors to the cortex of the brain and results in a cascade of
“rewarding” events. Bad stimulus is part of our early warning system
and will precipitate the “punishment” phase of our experience, pain or
a perception of discomfort. This is a simple principle, but some
therapists misunderstand the purpose of this protective mechanism and
attempt to provoke negative stimulation via manual techniques. They are
in effect working against the protective, survival, and homeostatic
mechanisms of the body. The body is always working against time and
change to maintain homeostasis, eventually it will lose the struggle
(death). In the time in between, the role of the therapist is to assist
the natural homeostatic processes of the body. What heals the body
best, is what copies the natural self regulating mechanisms of the body
itself, and not what stresses it further away from its balanced state.
Manual
and massage therapists have been searching for explanations regarding
how the effects that they see occurring in their patients have
happened. It is understandable that this search for meaning would lead
to theories and ideas regarding the nervous system. It is, however,
important that this search for knowledge regarding how the body and
brain function are based on real physiological and neurological
function and not on outdated or erroneous concepts and theories. This
is important in manual therapy because our understanding of theories
and concepts get translated into technique and treatment protocol.
These concepts are taught in schools and learned and practiced by
successive generations of therapists and become part of accepted
massage “therapy”. These techniques are practiced on thousands of
patients with either poor or no clinical response or treatment
outcomes, and this fact raises serious ethical concerns. Some of the
techniques sited here are currently being included in definitions of
medical massage by individuals who want to see there pet techniques or
training programs promoted in this manner. Medical massage is based on
research and the application of research based technique, not on
popular opinion regarding the inclusion of non physiological techniques
as medical massage. All massage therapy will facilitate certain general
physiological responses that involve homeostasis. Medical massage,
however, has a higher standard than just general physiological results.
Medical massage aims for specific measurable clinical outcomes that
address the chief complaint of the patient being treated.
As we
move towards a better understanding of how manual and massage therapies
cause change in the body and its systems, such as the nervous system,
we are building a foundation of science, based on research, and
refining our techniques into an effective methodology of treatment and
manual health care. The vast accumulation of scientific research
regarding the effects on the brain, and in turn the body, that results
from manual stimulation via direct manual and massage techniques,
therapeutic stretching, range of motion activities, ancillary
therapeutic modalities, and related systems such as acupuncture all
provide the contemporary manual therapist with the honest tools needed
to both explain to the skeptics the validity of manual medicine, but
also assist in the advancement of manual therapy as an accepted health
care modality for the treatment of a variety of disorders and diseases
both directly related to the musculo skeletal system, but also to more
global and universal physical and organic disorders and diseases that
are affected by neurohumoralbiophysiological responses mediated by the
central nervous system, upon which manual therapy can claim a direct
and significant effect.
Acupuncture built its original
scientific reputation on research into studies related to beta
endorphin release and the gate theory of pain. Because acupuncturists
were able, early on, to establish a research foundation and scientific
validity for their techniques acupuncture rapidly became legalized and
accepted by the scientific community. Members of the acupuncture
community were also able to present their research results
intelligently to the medical community. Manual therapy has not been as
effective in achieving this for several reasons. Some members of the
manual therapy community have been resistant to research and
advancement in education and training, and in a number of cases they
are openly hostile to the medical community. Additionally, many massage
theories and systems of therapy are anti scientific and are blatantly
based on non physiological, fringe or metaphysical concepts and ideas.
Research
is research, and the findings that it results in can often be
transferred from one manual modality to another, from one subject to
another, or from one field to another. A research discovery relating to
one manual therapy technique, or the mechanisms by which a technique
stimulates a response in the body, may be strongly suggestive of now
another manual therapy technique, that is similar in its stimulatory
effects, may work on the body’s physiology. Science often does this in
reverse, that is Dr. Hans Selye and subsequent researchers have
described how stressors affect the body in what has been called by
Selye, the General Adaptation Syndrome. So we know that the body
responds in certain well observed general ways to the pressures of
stress, we know how the nervous system responds, what hormones are
released, and the effects of all of this on cells, tissue, organs, and
systems of the body. Manual therapy has similar global effects on the
body.
We could use two analogies that explain and substantiate
manual therapy effects on the central nervous system, breastfeeding and
sexual activity. Both of these activities begin with tactile
stimulation of a part of the body innervated with sensory and motor
nerves. In the analogy of breastfeeding, the infant’s initiation of
tactile contact with the nipple and the suckling response results in
many complex neurological/humoral responses. The tactile sensation
results in transmission of impulses from the breast to the higher brain
via the spinothalamic tract. The higher brain communicates through the
limbic areas, the prefrontal cortex, and finally the hypothalamus that
in turn communicates with the posterior pituitary gland
(neurohyposhysis) resulting in a release of oxytocin and prolactin from
the anterior pituitary gland (adenohypophysis). These two hormones
arrive at the breast via blood circulation and the oxytocin initiates
the milk secretion.
This analogy demonstrates the effects of the
tactile stimulation of an area on the body with a profound and highly
complex physiological response occurring as a result of this
stimulation. In this analogy we see effects on the central nervous
system, hormonal responses, and circulation. Manual therapy can be
postulated to have similar mechanisms of action and effects, and these
effects are mediated via similar neuro/humoral activities in the brain,
from the cortex to the mid brain and lower brain. The resulting effects
of manual stimulation can affect the body’s physiology in a manner
similar to this breast feeding analogy, as profoundly, and can be said
to facilitate two physiological responses, one specific to the
stimulation and the other a more global and homeosomatic response on
body function. The second analogy related to human sexual responses
also demonstrates the effect of direct manual stimulation on areas or
regions of the body with tactile contact and the significant changes in
brain activity, neurological, hormonal, and circulatory function. In
other words, tactile stimulation has very beneficial effects on body
activity and response.
Homeosomatic responses reflect
homeostasis or a balance of physiological function within the central
systems of the body such as, nervous, endocrine, respiratory,
circulatory, and digestive. Cannon, Selye, and Benson presented these
“balancing” responses as homeostatis, or the relaxation response. The
use of non specific terminology to describe a complex physiological
activity in the body, does not mean that the activity is unimportant or
trivial. The documented effects of manual therapy reveal that it is a
therapeutic stimulus for both general and specific physiological
changes in the body. Manual therapies all share a common field of
stimulus, the human skin and connective tissue, and these organs have
been shown in studies done by A. Montagu and T. Fields to be essential
to the early preservation and promotion of human life itself.
The
above discussion reviews the established mechanisms by which manual
therapies share certain physiological effects. Other studies regarding
manual therapy have looked at pain mechanisms such as mechanoreceptor
stimulation, and endorphin release. These are not the only mechanisms
by which manual therapy affects body physiology specifically and
globally. Nor is the effect of manual therapy limited to the musculo
skeletal and connective tissue systems since it is known to effect
circulatory, endocrine, and the immune functions as well. The last 3 to
4 decades at have greatly added to our knowledge of how traditional
manual therapy affects the body’s physiological function. Some of the
early work involved theories regarding mechanisms of pain such as the
“gate theory” of Melzack and Wall. The work of Pomeranz introduced the
hypothesis that the higher brain was involved in mechanisms of pain
control, and that pain was mediated via multi directional and multi
sectional components of the brain, and not localized to one area of the
brain. The work of researchers such as Cho et al. using acupuncture
stimulation (which in other studies has been shown to stimulate
peripheral mechanoreceptors as manual tactile pressure does) as a
facilitating vector have demonstrated plausibility for involvement of a
neural circuit passing through the higher brain, including the sensory
cortex – multi modal association cortex – amygdala – prefrontal cortex
– amydala – and hypothalamus. It is within these neurological
structures that the facilitation of endocrine, autonomic and
physiological mechanisms for the establishment of homeostasis occurs.
It can be concluded that manual stimulation which is initiated in
tissues innervated with mechanoreceptors (almost everywhere) will
travel along peripheral sensory nerves and up the ascending tracts of
the spinal cord to the neuro cortex where, depending on the type of
stimulus and the source of the stimulus, and the patients perception of
the stimulus, the brain will direct a cascade of events that will
involve basic physiological homeostatsis, survival mechanisms
(amygdala), the balance of humoral and autonomic functions,
immunological modulation, and the control of neurochemicals elaborated
by both nervous and endocrine tissues and glands.
Current
imaging tools such as the CAT, MRI, and PET scanning systems allow a
deeper penetration of what used to be the “mysteries” of manual
therapies effect on the human body. Current research has both
invalidated past theories related to popular massage systems, while at
the same time establishing a foundational understanding of both the
specific and global effects of manual therapies. This research
demystifies our understanding of how these therapies work and how the
manual therapist can more effectively apply manual therapy technique in
the treatment of injury and disease. While many past and present
massage techniques and systems are based on the popular and highly
subjective opinions of personalities within the massage, manual therapy
or acupuncture communities, research makes most of these approaches
moot. By gaining a better understanding of how manual technique and
tactile stimulation affect the body both regionally and globally we can
refine our technique and treatment methods and advance both the art and
science of manual therapy. However, the massage community at large, at
this time, remains uninformed and misdirected regarding the research
and its importance to their profession and therapy. Massage practices
that provoke pain rather than inhibit it, that promote our attempt to
facilitate non physiological responses in the body, or that approach
therapy with the idea that muscles need to be stimulated in a specific
predetermined sequence, all miss the point. The human organism has
certain universal physiological responses that are stimulated via the
communication pathways inherently engineered into the body, and the
therapy that “speaks the same language” as this communication system,
by applying the appropriate biological “signal”, will facilitate the
corrective and restorative mechanisms that are “wired” into the nervous
system and that once processed by the higher brain will result in the
correct neurological or biochemical response by the body.
If you
would like to conduct your own investigation on the information and
concepts presented in this article read Eyal Lederman’s book,
Fundamentals of Manual Therapy, pages 97 and 98, as well as the rest of
his book. Additionally, for the latest muscle physiological research
look at biomechanics and muscle architecture research at Stanford or
conduct an internet search with the key words “muscle physiology”,
“muscle architecture”, or “biomechanics research”.
The author of
this article may be contacted through the American Medical Massage
Association website at www.americanmedicalmassage.com
References:
Fundamentals of Manual Therapy, Lederman E., Churchill Livingstone (1997)
Fundamentals of Medical Massage Therapy, Lawton G., American Health Source (1980) Current Edition 2002
Textbook of Pain, Melzack R. and Wall, P., 4th Edition, Churchill Livingstone
Medical Acupuncture, A Western Scientific Approach, Filshie J., White A., Churchill Livingstone (1998)
Neuro-Acupuncture, Cho Z.H., Wong E.K., Fallon J., Q-puncture (2001)
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