Plasticidad Fascial

Fascial plasticity – a newneurobiological explanation:

Part 1. . . . . . . . . . . . .

Robert Schleip

In myofascial manipulation an immediate tissue release is often felt under the working

hand. This amazing feature has traditionally been attributed to mechanical properties

of the connective tissue. Yet studies have shown that either much stronger forces or

longer durations would be required for a permanent viscoelastic deformation of fascia.

Fascia nevertheless is densely innervated by mechanoreceptors which are responsive to

manual pressure. Stimulation of these sensory receptors has been shown to lead to a

lowering of sympathetic tonus as well as a change in local tissue viscosity. Additionally

smooth muscle cells have been discovered in fascia, which seem to be involved in active

fascial contractility. Fascia and the autonomic nervous system appear to be intimately

connected. A change in attitude in myofascial practitioners from a mechanical

perspective toward an inclusion of the self-regulatory dynamics of the nervous system

is suggested. r 2003 Elsevier Science Ltd. All rights reserved.

Introduction

Fascia – what a fascinating tissue!Also known as dense irregularconnective tissue, this tissuesurrounds and connects everymuscle, even the tiniest myofibril,and every single organ of the body.It forms a true continuity

throughout our whole body. Fasciahas been shown to be an importantelement in our posture andmovement organization. It is oftenreferred to as our organ of form

(Varela & Frenk 1987, Garfin et al.1981).

Many approaches to manualtherapy focus their treatment on thefascia. They claim to alter either thedensity, tonus, viscosity or

arrangement of fascia throughthe application of manual pressure(Barnes 1990, Cantu & Grodin1992, Chaitow 1980, Paoletti 1998,Rolf 1977, Ward 1993). Theirtheoretical explanations usuallyrefer to the ability of fascia toadapt to physical stress. How thepractitioner understands the natureof this particular responsivenessof fascia will of course influencethe treatment. Unfortunately,fascia is often referred to in termsof its mechanical properties alone.This series of articles will notonly explore the neural dynamicsbehind fascial plasticity, butwill also offer new perspectivesfor myofascial treatmentmethods.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Journal of Bodywork and Movement Therapies (2003)

7(1),11^19r 2003 Elsevier Science Ltd. All rights reserved.

doi:10.1016/S1360-8592(02)00067-0

S1360-8592/03/$ - see front matter

Robert Schleip MA

Rolfing Faculty, European Rolfing Association

e.V., Kapuzinerstr. 2S, D-80337, Munich, Germany

Correspondence to: Robert Schleip

E-mail: [email protected]

Website: www.somatics.de

Received April 2002

Revised May 2002

Accepted June 2002

F A S C I A L P H Y S I O L O G Y

11

JOURNAL OF BODYWORK AND MOVEMENT THERAPIES JANUARY 2003

The classical gel-to-solmodel

Many of the current training schoolswhich focus on myofascial treatmenthave been profoundly influenced byRolf (1977). In her own work Rolfapplied considerable manual orelbow pressure to fascial sheets inorder to change their density andarrangement. Rolf’s ownexplanation was that connectivetissue is a colloidal substance inwhich the ground substance can beinfluenced by the application ofenergy (heat or mechanicalpressure) to change its aggregateform from a more dense ‘gel’ state toa more fluid ‘sol’ state. Typicalexamples of this are common gelatinor butter, which get softer byheating or mechanical pressure.This gel-to-sol transformation,also called thixotropy (Juhan 1987),has been positively confirmed tooccur as a result of long-termmechanical stress applications toconnective tissue (Twomey andTaylor 1982).

But the question arises: is thismodel also useful to explain theimmediate short-term plasticity offascia? In other words, what actuallyhappens when a myofascialpractitioner claims to feel a ‘tissue

release’ under the working hand? Inmost systems of myofascialmanipulation, the duration of anindividual ‘stroke’ or technique on aparticular spot of tissue is between afew seconds and 1 1

2minute. Rarely is

a practitioner seen – or is it taught –to apply uninterrupted manualpressure for more than 2minutes.Yet often the practitioners reportfeeling a palpable tissue releasewithin a particular ‘stroke’. Suchrapid – i.e. below 2minutes – tissuetransformation appears to be moredifficult to explain with thethixotropy model. As will be shownlater, studies on the subject of ‘time

and force dependency’ of connectivetissue plasticity (in terms of creep

and stress relaxation) have shownthat either much longer amounts oftime or significantly more force arerequired for permanent deformationof dense connective tissues (Currier& Nelson 1992).

Additionally the problem ofreversibility arises: in colloidalsubstances the thixotropic effectlasts only as long as the pressure orheat is applied. Within minutes thesubstance returns to its original gelstate – just think of the butter in thekitchen. This is definitely not anattractive implication of this modelfor the practitioner.

Piezoelectricity ^ or thebody as a liquid crystal

Oshman and others have addedpiezoelectricity as an intriguingexplanation for fascial plasticity(Oshman 2000, Athenstaedt 1974).Piezo (i.e. pressure) electricity existsin crystals in which the electriccenters of neutrality on the inside ofthe crystal lattice are temporarilyseparated via mechanical pressurefrom the outside and a small electriccharge can be detected on thesurface. Since connective tissue canbe seen to behave like a ‘liquidcrystal’ (Juhan 1987), these authorspropose that the cells which produceand digest collagen fibers (calledfibroblasts and fibroclasts) might beresponsive to such electric charges.To put it simply: pressure from theoutside creates a higher electriccharge, which then stimulates thefibroblasts to increase theirproduction rate of collagen fibersin that area. Additionally thefibroclasts might have a selectivebehavior not to ‘eat’ fibers which areelectrically charged. In a nutshell:more stress, more charge, morefibers. Similar processes havealready been shown to exist in boneformation after fractures as well asin wound healing.

Nevertheless, the processesinvolved seem to require time as an

important factor. The half-life spanof non-traumatized collagen hasbeen shown to be 300–500 days, andthe half-life of ground substance1.7–7 days (Cantu & Grodin 1992).While it is definitely conceivable thatthe production of both materialscould be influenced bypiezoelectricity, both life cyclesappear too slow to account forimmediate tissue changes that aresignificant enough to be palpated bythe working practitioner.

The traditionalexplanations areinsu⁄cient

Both models, thixotropy andpiezoelectricity, are appealingconcepts to explain long-term tissuechanges. Yet it seems, additionalmodels are needed when it comes toshort-term plasticity. Laboratorystudies on the subject of time andforce dependency of connectivetissue plasticity (in vitro as well as invivo) have shown the followingresults: in order to achieve apermanent elongation of collagenfibers one needs to apply either anextremely forceful stretch of 3–8percent fiber elongation, which willresult in tissue tearing along withinflammation and other side effectswhich are usually seen asundesirable in a myofascial session.E.g. for an 18mm distal iliotibialband such permanent elongationhappens at 60 kg and more(Threlkeld 1992). Or it takes morethan an hour (which can be taken atseveral intervals) with softer 1–1.5percent fiber elongation, if onewants to achieve permanentdeformation without tearing andinflammation (Currier & Nelson1992, Threlkeld 1992).

For short-term application ofstress the typical relationships areshown in Fig. 1. Microfailure is seenas the breaking of some individualcollagen fibers and of some fiberbundles which results in a

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permanent (plastic) elongation ofthe tissue structure. This is followedby a cycle of tissue inflammationand repair. Based on measurementswith different kinds of paraspinaltissues, Threlkeld calculates thatmicrofailure occurs at around 224–1.136N which equals 24–115 kg(Threlkeld 1992). While high-velocity thrust techniques mightcreate forces within that range, itseems clear that the slower softtissue manipulation techniques arehardly strong enough to create thedescribed tissue response.

This research leads to a simplethought experiment. In everyday lifethe body is often exposed to pressuresimilar to the application of manualpressure in a myofascial treatmentsession. While the body naturallyadapts structurally to long-termfurniture use, it is impossible toconceive that adaptations couldoccur so rapidly that any unevenload distribution in sitting (e.g.while reading this article) wouldpermanently alter the shape of yourpelvis within a minute. It seemsessential therefore that we find

additional models – besides thethixotropic and piezoelectricconcepts – to account for thepalpable tissue changes that occur ina treatment session.

The need for a more rapidself-regulatory system

From an evolutionary perspective itmakes sense that animals have aslowly adapting plasticity system inorder to adjust to patterns of long-term use. In addition to this capacitythey have also developed a morerapid system of adapting their formand local tissue density to temporarydemands. This regulation system isopen for adaptation to how theanimal perceives its interaction withthe environment. It seems logicalthat this ability of being morerapidly adaptable is mediated by –or at least connected to – a bodysystem which is involved in theperception of our needs as well as ofthe environment. Traditionally, thisbody system has been called thenervous system.

It is therefore suggested that theself-regulatory qualities of the

client’s nervous system must beincluded in an explanatory model ofthe dynamics of fascial plasticity inmyofascial manipulations. Theauthor’s own experiments in treatinganesthetized people (with verysimilar results to that noted whenmanually treating very fresh piecesof animal meat) have shown thatwithout a proper neural connection,the tissue does not respond as it doesunder normal circumstances(Schleip 1989).

Although it has not beenconsidered very much in recenttimes, the inclusion of the nervoussystem in attempting to understandfascial responsiveness is not a newconcept altogether, since thefounder of osteopathy AndrewTaylor Still wrote more than acentury ago.

The soul of man with all the streams of

pure living water seems to dwell in the

fascia of his body. When you deal with

the fascia, you deal and do business

with the branch offices of the brain,

and under the general corporation law,

the same as the brain itself, and why

not treat it with the same degree of

respect? (Still 1899).

The nervous system asa wet tropical jungle

Many people think of the nervoussystem as an old-fashionedtelephone switchboard system of theindustrial age and thereforeincapable of representing finer andmore complex processes such as ‘lifeenergy’, etc. The reader is cordiallyinvited to consider this to be anoutdated model. Current concepts inneurobiology see the brain more as aprimarily liquid system in which fluiddynamics of a multitude of liquidand even gaseous neurotransmittershave come to the forefront.Transmission of impulses in ournervous system often happens viamessenger substances that travelalong neural pathways as well asthrough the blood, lymph,

Fig. 1 Stress–strain curve of dense connective tissue. Most forces generated during daily life load

the tissue in the linear region of the curve and produce non-permanent elongation. Microfailure

with permanent elongation happens at extreme loads only and is accompanied by tearing and

inflammation. The region of overlap of the microfailure zone with the physiologic loading zone

varies with the density and composition of the tissue, yet for most fascial tissues it would be well

above a 20 kg loading (drawing based on Threlkeld 1992). Figure by Twyla Weixl, Munich,

Germany.

Fascial plasticity

13


cerebrospinal fluid or groundsubstance (Kandel 1995). Thisglobal system for rapid bodyregulations is inseparably connectedwith the endocrinal and immunesystem. Rather than picturing thenervous system as a hard-wiredelectric cable system (which in theview of many bodyworkers is thenof course incapable of beinginvolved in more subtle energeticphenomena) picture it in yourmind’s eye as a wet tropical jungle

(Schleip 2000). This jungle is a self-regulatory field with an amazingamount of complexity, continualreorganization and plasticity, evenin adults.

The Golgi re£ex arc asa breakthrough

Unfortunately, the precise details ofthe neural dynamics of fascia haverarely been explored. Cottingham(1985) presented a milestoneproposal when he suggested aneurophysiological concept whichwas readily adopted by otherauthors (Ward 1993, Schleip 1989)and which will be briefly describedhere: Golgi receptors are said to befound all over in dense properconnective tissues. They exist inligaments (here called Golgi end

organs), in joint capsules, as well asaround myotendinous junctions(here called Golgi tendon organs).These sensory receptors arearranged in series with fascial fibersand respond to slow stretch byinfluencing the alpha motor neuronsvia the spinal cord to lower theirfiring rate, i.e. to soften relatedmuscle fibers. Cottingham suggestedthat during soft tissue manipulation– as well as in Hatha yoga posturesand slow active stretching – theseGolgi receptors are stimulated,which results in a lower firing rate ofspecific Alpha motor neurons, whichthen translates into a tonus decreaseof the related tissues.

Too bad ^ it is not a simplere£ex!

Unfortunately, later research hasshown that passive stretching of amyofascial tissue does not stimulatethe Golgi tendon organs (Jami1992). Such a stimulation happensonly when the muscle fibers areactively contracting. The reason forthis lies in the arrangement of theGolgi tendon receptors. They arearranged in series with the musclefibers. When the muscle with itsrelated myofascia is passivelyelongated, most of the stretch will betaken up or ‘swallowed’ by aresulting elastic elongation of themuscle fibers. This is of coursedifferent in active clientcontractions, in which the Golgitendon organs function to providefeedback information aboutdynamic force changes during thecontraction (Lederman 1997).

But there are other Golgireceptors

Does this mean that deep tissuework (in which the client often ispassive) will not involve the Golgireflex loop? Perhaps, but notnecessarily. These measurementshave been done with passive jointextension movements, and not yetwith the application of direct tissuepressure as in a myofascialmanipulation.

Furthermore, it is important tonote that only less than 10% of theGolgi receptors are found whollywithin tendon. The remaining 90%are located in the muscular portionsof myotendinous junctions, in theattachment transitions ofaponeuroses, in capsules, as well asin ligaments of peripheral joints(Burke and Gandeva 1990).

Studies of the fine antigravityregulation in bipedal stance havealso revealed a new functional rolefor Golgi receptors. In order tohandle the extreme antigravity

balancing challenges as a biped, ourcentral nervous system can reset theGolgi tendon receptors and relatedreflex arcs so that they function asvery delicate antigravity receptors(Dietz et al. 1992). This explains thatsome of the leg’s balancing reactionsin standing occur much quicker thanit would take for a nerve impulsefrom the brain to the leg. In otherwords, the previously discussed andwell-documented role of the Golgiorgans (as a feedback mechanismabout dynamic force changes duringactive contractions) covers only aminor functional role of theseorgans. For example, little is knownabout the sensitivity and relatedreflex function of those Golgireceptors that are located inligaments (Chaitow 1980) or in jointcapsules. It seems possible – yet alsoquite speculative – to assume thatthese less-explored Golgi receptorscould indeed be stimulated withsome stronger deep tissue techniques(Table 1).

And there are Ru⁄ni andPacini corpuscles

A detailed histochemical study ofthe thoracolumbar fascia at theBiomedical Engineering Institute ofthe Ecole Polytechnique in Montrealrevealed that it is richly populatedby mechanoreceptors (Yahia et al.1992). The intrafascial receptorswhich they described consist of threegroups. The first group are the largePacini corpuscles plus the slightlysmaller Paciniform corpuscles. Theegg-shaped Pacini bodies respond torapid changes in pressure (yet not toconstant unchanging pressure) andto vibrations. A bit smaller are thePaciniform corpuscles, which have asimilar function and sensitivity. Asecond group are the smaller andmore longitudinal Ruffini organswhich do not adapt as quickly andtherefore respond also to long-termpressure. It seems likely that thePacinian receptors are being

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stimulated only by high-velocitythrust manipulations as well as invibratory techniques, whereas theRuffini endings will also be activatedby slow and deep ‘melting quality’soft tissue techniques.

Both types of intrafascialmechanoreceptors, the Pacinian/Paciniform and the Ruffini bodies,are found in all types of denseproper connective tissue, i.e. inmuscle fascia, tendons, ligaments,aponeuroses, and joint capsules. Inmyotendinous junctions thePacinian corpuscles are morefrequent on the tendinous site (asopposed to the Golgi tendon organswhich are more frequent on themuscular site). They have also beenshown to be more frequent in thedeeper portions of joint capsules, indeeper spinal ligaments, and in

investing (or enveloping) muscularfasciae like the antebrachial, crural,abdominal fascia or the fascia of themasseter, the lateral thigh, in plantaras well as palmar tissues, and in theperitoneum (Stilwell 1957). TheRuffini endings are specially dense intissues associated with regularstretching like the outer layer of jointcapsules, the Dura mater, the

ligaments of peripheral joints, andthe deep dorsal fascia of the hand.At the knee joint the Ruffini endingsare more frequent at anterior andposterior ligamentous and capsularstructures, whereas Pacinian bodiesare more accumulated medially andlaterally of the joint (van den Berg &Capri 1999).

It is of interest to note that Ruffiniendings are specially responsive totangential forces and lateral stretch(Kruger 1987) and that stimulationof Ruffini corpuscles is assumed toresult in a lowering of sympatheticnervous system activity (van denBerg & Capri 1999). This seems to fitto the common clinical finding thatslow deep tissue techniques tend tohave a relaxing effect on local tissuesas well as on the whole organism.

Our reference scene

Figure 3 illustrates the neural tissueplasticity dynamics at this level. Itis suggested that the followingscene should be used as a referencepoint for this article. Imagine apractitioner working slowly withthe connective tissue around thelateral ankle, in an area with no

striated muscle fibers. (Choosingthis reference scene allows us tofocus on intrafascial dynamicsonly, and – for the purpose of thisarticle – to ignore the stimulationof intramuscular mechanoreceptorsand other effects which would beinvolved in the analysis of manyother myofascial workingsituations.) If that practitionerreports a ‘tissue release’, what hashappened? Possibly the manualtouch stimulated some Ruffiniendings which then triggered thecentral nervous system to changethe tonus of some motor units inmuscle tissue which is mechanicallyconnected to the tissue under thepractitioner’s hand.

An unknown universewithin us

In order to discuss the third groupof intrafascial mechanoreceptorsdescribed by Yahia and hercolleagues in Montreal, it isnecessary to go on a short excursion.It commonly comes as a big surpriseto many people to learn that ourrichest and largest sensory organ isnot the eyes, ears, skin, or vestibular

Table1 Mechanoreceptors in fascia

Receptor type Preferred location Responsive to Known results of stimulation

Golgi

Type Ib

K Myotendinous junctions

K Attachment areas of aponeuroses

K Ligaments of peripheral joints

K Joint capsules

K Golgi tendon organ: to

muscular contraction.

K Other Golgi receptors: probably

to strong stretch only

Tonus decrease in related

striated motor fibers

Pacini and Paciniform

Type II

K Myotendinous junctions

K deep capsular layers

K spinal ligaments

K investing muscular tissues

Rapid pressure changes and vibrations Used as proprioceptive

feedback for movement control

(sense of kinesthesia)

Ruffini

Type II

K Ligaments of peripheral joints,

K Dura mater

K outer capsular layers

K and other tissues associated

with regular stretching.

K Like Pacini, yet also to sustained pressure.

K Specially responsive to

tangential forces (lateral stretch)

Inhibition of sympathetic activity

Interstitial

Type III and IV

K Most abundant receptor type.

Found almost everywhere,

even inside bones

K Highest density in periosteum.

K Rapid as well as sustained pressure

changes.

K 50% are high-threshold units, and 50%

are low-threshold units

K Changes in vasodilation

K plus apparently in plasma

extra-vasation

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system but is in fact our muscleswith their related fascia. Our centralnervous system receives its greatestamount of sensory nerves from ourmyofascial tissues. Yet the majorityof these sensory neurons are so smallthat until recently little has beenknown about them (Engeln 1994).

If one studies a typical musclenerve (e.g. the tibial nerve), itconsists of almost three times moresensory fibers than motor fibers.This points to a fascinating principlethat sensory refinement seems to bemuch more important than themotor organization. However let usnot get distracted by this. Whilemany of the nerve fibers in a typicalmotor nerve have a vasomotorfunction, which regulate blood flow,the largest group of fibers aresensory nerves. Now comes the reallyinteresting point: of these sensorynerves only a small fraction, or 20%,belong to the well-known types Iand II nerves which originate inmuscle spindles, Golgi organs,Pacini corpuscles and Ruffiniendings (see Fig. 2). The majority, orfour times as many, belong to aninteresting group of types III and IV

sensory nerves which are hardlymentioned in most textbooks(Mitchell & Schmidt 1977).

What dowe know aboutthis hidden network?

These hidden neurons are muchsmaller in diameter and are nowcommonly called interstitial muscle

receptors. A better name would beinterstitial myofascial tissue

receptors since they also existabundantly in fascia. A minority ofthese nerves are covered by a verythin myelin sheath (type III), but90% of these nerves areunmyelinated (type IV). Theseinterstitial receptors are slower thanthe types I and II nerves and most ofthem originate in free nerve endings.

In the past it was assumed thatthese nerve endings are mostly painreceptors. Some have also beenshown to be involved in thermo- orchemoception. While many of thesereceptors are multimodal, researchhas shown that the majority of theseinterstitial receptors do in factfunction as mechanoreceptors, whichmeans they respond to mechanicaltension and/or pressure (Mitchell &Schmitt 1977).

This large group of interstitialmechanoreceptors can be furtherdivided into two subgroups of equalsize: low-threshold pressure units(LTP units) and high-threshold units

(HTP). A study of the Achillestendon of cats revealed that abouthalf of types III and IV endingsencountered were LTP units andresponded to light touch, even totouch as light as ‘‘with a painter’s

brush’’ (Mitchell & Schmidt 1977).Based on this latter finding, does itnot seem possible – indeed likely –that soft tissue manipulation mightinvolve stimulation of types III andIV receptors?

Recent insights into thephysiology of pain have shown thatseveral interstitial tissue receptorsfunction both as mechanoreceptors(usually as HPT units) and as painreceptors. In the presence of pain –and the support of variousneuropeptides – their sensitivitychanges such that normalphysiological pressure changes oftenlead to strong and chronic firing ofthese receptors. This explains whycurrent research has revealed thatpain often exists without anymechanical irritation of nervousstructures as was frequentlyassumed by the root-compressionmodel (Chaitow & DeLany 2000).

What are they doing?

This of course triggers the questionabout the natural functional role ofinterstitial mechanoreceptors in thebody. What regular consequences orreactions have been associated withan excitation of this hidden and richsensory network? Of course some ofthem function as pain receptors. By1974 a Japanese study had alreadyrevealed that types III and IVreceptors in the fascia of temporalis,masseter and infrahyoid musclesshow ‘responses to the mandibular

movement and the stretching of the

fascia and the skin’, and it wastherefore suggested that these nerveendings are concerned ‘with the

sensation of position and movement of

the mandible’ (Sakada 1974).Furthermore the majority of these

types III and IV mechanoreceptors

Fig. 2 Within a typical muscle nerve there are almost three times as many sensory neurons than

motor neurons. Note that only a small portion of the sensory information comes from types I and

II afferents which originate in muscle spindles, Golgi receptors, Pacinian and Ruffini endings. The

majority of the sensory input comes from the group of types III and IV afferents or interstitial

receptors which are intimately linked with the autonomic nervous system. Figure by Twyla Weixl,

Munich, Germany.

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have been shown to have autonomic

functions, i.e. stimulation of theirsensory endings leads to a change inheart rate, blood pressure,respiration, etc. Stimulation of typeIV receptors tends to increasearterial blood pressure (Coote &Perez-Gonzales 1970) whereasstimulation of type III receptors canboth increase and decrease bloodpressure. Several studies have shownthat an increase of static pressure onmuscles tends to lower arterial bloodpressure (Mitchell & Schmitt 1977).It seems that a major function ofthis intricate network of interstitialtissue receptors is to fine tune thenervous system’s regulation of bloodflow according to local demands,and that this is done via very closeconnections with the autonomicnervous system.

Touch research with catsand humans

Based on this research it should notcome as a surprise that slow deeppressure on the soft tissue of cats hasbeen shown to lead to a reduction inmuscle tonus measured by EMGactivity (Johansson 1962) and thatslow stroking of the back in catsproduces a reduction in skintemperature as well as signs ofinhibition of the gamma motorsystem (von Euler & Soderberg1958).

Furthermore, it has been proventhat deep mechanical pressure to thehuman abdominal region (Folkow1962), as well as sustained pressureto the pelvis (Koizumi & Brooks1972), produces parasympatheticreflex responses, includingsynchronous cortical EEG patterns,increased activity in vagal fibers, anda decreased EMG activity.

According to the model ofhypothalamic tuning states by ErnstGellhorn, an increase in vagal tonedoes not only trigger changes in theautonomic nervous system andrelated inner organs, but also tends

to activate the anterior lobe of thehypothalamus. Such a ‘trophotropic

tuning’ of the hypothalamus theninduces a lower overall muscletonus, more quiet emotionalactivity, and an increase insynchronous cortical activity, bothin cats as well as in humans(Gellhorn 1967). It thereforeappears that deep manual pressure –specifically if it is slow or steady –stimulates interstitial and Ruffinimechanoreceptors, which results inan increase of vagal activity, whichthen changes not only local fluiddynamics and tissue metabolism,but also results in global musclerelaxation, as well as a morepeaceful mind and less emotionalarousal.

On the other hand, sudden deeptactile pressure or pinching or othertypes of strong and rapidmanipulations have been shown toinduce a general contraction ofskeletal muscles (Eble 1960),particularly of ‘genetic flexormuscles’ (Schleip 1993) which areinnervated via a ventral primaryramus from the spinal cord.

Talking to the belly brain

Mechanoreceptors have been foundabundantly in visceral ligaments aswell as in the Dura mater of thespinal cord and cranium. It seemsquite plausible that most of theeffects of visceral or craniosacralosteopathy could be sufficientlyexplained by a simulation ofmechanoreceptors with resultingprofound autonomic changes, andmight therefore not need to rely onmore esoteric assumptions(Arbuckle 1994).

Recent discoveries concerning therichness of the enteric nervous system

(Gershon 1999) have taught us thatour ‘belly brain’ contains more than100 million neurons and workslargely independent of the corticalbrain. It is interesting to note thatthe very small connection between

these two brains of a few thousandneurons consists of nine times asmany neurons involved in processesin which the lower brain tells theupper one what to do, comparedwith the number of neuronsinvolved in the top-down direction.Many of the sensory neurons of theenteric brain are mechanoreceptors,which – if activated – trigger amongother responses, importantneuroendocrine changes. Theseinclude a change in the productionof serotonin – an important corticalneurotransmitter 90% of which iscreated in the belly – as well as otherneuropeptides, such as histamine

(which increases inflammatoryprocesses).

What are we doing?

Myofascial manipulation involves astimulation of intrafascialmechanoreceptors. Theirstimulation leads to an alteredproprioceptive input to the centralnervous system, which then resultsin a changed tonus regulation ofmotor units associated with thistissue (Fig. 3). In the case of a slowdeep pressure, the relatedmechanoreceptors are most likelythe slowly adapting Ruffini endingsand some of the interstitialreceptors; yet other receptors mightbe involved too (e.g. spindlereceptors in affected muscle fibersnearby and possibly someintrafascial Golgi receptors).

Measurements on themechanoreceptors of the knee jointligaments have shown that theirstimulation leads to weak effects inalpha motor neurons, yet topowerful changes in gamma motorneurons. This means that theseligamentous mechanoreceptors areprobably used as proprioceptivefeedback for preparatory regulation(preprogramming) of muscle tonusaround this joint (Johansson et al.1991). For myofascial practitionersthis is fascinating news, as it suggests

Fascial plasticity

17


that simulation of fascialmechanoreceptors may primarilylead to changes in gamma motortone regulation. While the alpha andgamma motor system are usuallycoactivated, there are someimportant differences between them.The alpha system originatesprimarily in the cortex, and it isparticularly involved in volitionaland precise movements of theextremities, whereas the gammasystem originates in older brain stemstructures and plays a strong role inthe more global and unconsciouspostural organization of antigravity-extensor muscles and chronicmusculo-emotional attitudes(Glaser 1980, Henatsch 1976,Juhan 1987).

Nomuscle is a functionalunit

When discussing any changes inmotor organization, it is importantto realize that the central nervoussystem does not operate ‘in muscles’,i.e. a muscle is never activated as awhole. The functional units of themotor system are the so-called motor

units, of which we have severalmillion in our body, much like aschool of fish that have learned toswim together. Depending on thequality of sensory feedback, thesemillions of motor units can be

individually regulated (Basmajian &De Luca 1985). We can now applythis understanding to our referencescene, in which a practitioner isworking on the connective tissuearound the lateral ankle. When thepractitioner reports a tissue release,it may be that it is caused by alowered firing rate of only a few fish(motor units) in the vicinity, andthat this movement is transmitted tothe tissue under the practitioner’shand. If the practitioner then feelsthe change and responds in a

supportive way toward theseparticular fish, other fish may soonfollow the new direction, which ofcourse leads to additional ‘releasesensations’ for the practitioner, andso on (Fig. 4).

Conclusion

Immediate fascial plasticity cannotbe understood by mechanicalproperties alone. Fascia is denselyinnervated by mechanoreceptors.Manual stimulation of these sensoryendings probably leads to tonuschanges in motor units which aremechanically linked to the tissueunder the practitioner’s hand. Atleast some of these responses areprimarily regulated by a change ingamma motor tone, rather than inthe more volitional alpha motorsystem. Of particular interest are theRuffini organs (with their highresponsiveness to tangentialpressure) and the very rich networkof interstitial receptors, sincestimulation of both of thesereceptors can trigger profoundchanges in the autonomic nervoussystem. Part 2 of this article series

Tonus change Centralof related skeletal Nervous System

motor units

Palpable tissue Stimulation ofresponse mechanoreceptors

Tissue manipulations

Fig. 3 The ‘Central Nervous System Loop’ (inspired by Cottingham). Stimulation of

mechanoreceptors leads to a lowered tonus of skeletal motor units which are mechanically linked

with the tissue under the practitioner’s hand. The involved intrafascial mechanoreceptors are

most likely Ruffini endings, Pacinian corpuscles (with more rapid manipulations), some of the

interstitial receptors, plus possibly some intrafascial Golgi receptors.

Fig. 4 Myofascial tissue as a school of fish. A practitioner working with myofascial tissue may

feel several of the motor units responding to touch. If the practitioner then responds supportively

to their new behavior, the working hand will soon feel other fish joining, and so forth. Figure by

Twyla Weixl, Munich, Germany.

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will include the discovery andfunction of intrafascial smoothmuscle cells. It will show how fascialmechanoreceptors can triggerimmediate viscosity changes of theground substance, and howfibromyalgia might be related to allthat. Several practical applicationsfor the practitioner will be given.

REFERENCES

Arbuckle BE 1994 Selected Writings.

Indianapolis American Academy of

Osteopathy

Athenstaedt H 1974 Pyroelectric and

piezoelectric properties of vertebrates.

Annals of the New York Academy of

Sciences 238: 68–110

Barnes JF 1990 Myofascial Release: The

Search of Excellence. Rehabilitation

Services Inc., Paoli, PA, Medicine, W.B.

Saunders Co.

Basmajian JV, De Luca C 1985 Muscles Alive

– Their Functions Revealed by

Electromyography. Williams & Wilkins,

Baltimore

Burke D, Gandeva SC 1990 Peripheral motor

system, In: Paxines G (ed). The Human

Nervous System Vol. 1: Academic Press,

San Diego, p 133

Cantu RI, Grodin AJ 1992 Myofascial

Manipulation – Theory and Clinical

Application. Aspen Publication,

Gaithersburg, MD

Chaitow L 1980 Soft Tissue Manipulation.

Thorsons, Wellingborough

Chaitow L, DeLany JW 2000 Clinical

Application of Neuromuscular

Techniques, Vol. 1. Churchill

Livingstone, Edinburgh

Cottingham JT 1985 Healing through Touch

– A History and a Review of the

Physiological Evidence. Rolf Institute

Publications, Boulder, CO

Coote JH, Perez-Gonzales JF 1970 The

response of some sympathetic neurons to

volleys in various afferent nerves. Journal

of Physiology London 208: 261–278

Currier DP, Nelson RM 1992 Dynamics of

Human Biologic Tissues. F.A. Davis

Company, Philadelphia

Dietz V et al. 1992 Regulation of bipedal

stance: dependency on ‘load’ receptors.

Experimental Brain Research 89: 229–

231

Eble JN 1960 Patterns of response of the

paravertebral musculature to visceral

stimuli. American Journal of Physiology

198: 429–433

Engeln H 1994 Konzert der Muskeln und

Sinne. GEO Wissen May: 90–97

Folkow B 1962 Cardiovascular reactions

during abdominal surgery. Annals of

Surgery 156: 905–913

Garfin SR et al. 1981 Role of fascia in

maintenance of muscle tension and

pressure. Journal of Applied Physiology

51(2): 317–320

Gellhorn E 1967 Principles of Autonomic–

Somatic Integration: Physiological Basis

and Psychological and Clinical

Implications. University of Minesota

Press, Minneapolis, MN

Gershon MD 1999 The Second Brain.

Harper-Collins, New York

Glaser V 1980 Eutonie. Karl F. Haug Verlag,

Heidelberg

Henatsch H-D 1976 Bauplan der peripheren

und zentralen sensomotorischen

Kontrollen. In: Physiologie des

Menschen, Vol. 14. Urban &

Schwarzenberg Munchen

Heppelman B et al. 1995 Fine sensory

innervation of the knee joint capsule by

group III and group IV nerve fibers in the

cat. Journal of Comparative Neurology

251: 415–428

Jami L 1992 Golgi tendon organs in

mammalian skeletal muscle: functional

properties and central actions.

Physiological Reviews 73(3): 623–666

Johansson B 1962 Circulatory response to

stimulation of somatic afferents. Acta

Physiologica Scandinavica 62 (Suppl.

198): 1–92

Johansson H et al. 1991 Receptors in the knee

joint ligaments and their role in the

biomechanics of the joint. Critical

Reviews in Biomedical Engineering 18(5):

341–368

Juhan D 1987 Job’s Body. Station Hill Press,

Barrytown, NY

Kandel ER 1995 Essentials of neural science

and behavior. Appleton & Lange, New

York

Koizumi K, Brooks C 1972 The integration

of autonomic system reactions: a

discussion of autonomic reflexes, their

control and their association with

somatic reactions. Ergebnisse der

Physiologie 67: 1–68

Kruger L 1987 Cutaneous sensory system. In:

Adelman G (ed.). Encyclopedia of

Neuroscience: Vol. 1 pp 293–294

Lederman E 1997 Fundamentals of Manual

Therapy. Churchill Livingstone,

Edinburgh

Mitchell JH, Schmidt RF 1977

Cardiovascular reflex control by afferent

fibers from skeletal muscle receptors.

In: Shepherd JT et al. (eds). Handbook

of Physiology, Sect. 2, Vol. III,

Part 2. American Physiological Society

Bethesda, MA, pp 623–658

Oshman JL 2000 Energy Medicine. Churchill

Livingstone, Edinburgh

Paoletti S 1998 Les Fascias – Role des Tissues

dans la Mecanique Humaine. Le Prisme,

Vannes cedex, France

Pongratz D, Spath M 2001 Fibromyalgia.

Fortschritte der Neurologie und

Psychiatrie 69(4): 189–193

Price JM et al. 1981 Biomechanics.

Mechanical Properties of Living

Tissues. Springer Verlag, New York,

pp 371–379

Rolf IP 1977 Rolfing: The Integration of

Human Structures. Dennis Landman,

Santa Monica

Sakada S 1974 Mechanoreceptors in fascia,

periosteum and periodontal ligament.

Bulletin of the Tokyo Medical and

Dental University 21 (Suppl.): 11–13

Schleip R 1989 A new explanation of the

effect of Rolfing. Rolf Lines 15(1): 18–20

Schleip R 1993 Primary reflexes and

structural typology. Rolf Lines 21(3):

37–47

Schleip R 2000 Lichtblicke im Dschungel der

Gehirnforschung. FeldenkraisZEIT 1:

47–56

Still AT 1899 Philosophy of Osteopathy.

Academy of Osteopathy, Kirksville, MO

Stilwell D 1957 Regional variations in the

innervation of deep fasciae and

aponeuroses. The Anatomical Record

127(4): 635–653

Threlkeld AS 1992 The effects of manual

therapy on connective tissue. Physical

Therapy 72(12): 893–901

Twomey L, Taylor J 1982 Flexion, creep,

dysfunction and hysteresis in the

lumbar vertebral column. Spine 7(2):

116–122

van den Berg F, Cabri J 1999 Angewandte

Physiologie – Das Bindegewebe des

Bewegungsapparates verstehen und

beeinflussen. Georg Thieme Verlag,

Stuttgart, Germany

Varela FJ, Frenk S 1987 The organ of form:

towards a theory of biological shape.

Journal of Social Biology and Structure

10: 73–83

von Euler C, Soderberg V 1958 Co-ordinated

changes in temperature thresholds for

thermoregulatory reflexes. Acta

Physiologica Scandinavica 42: 112–129

Ward RC 1993 Myofascial release concepts.

In: Basmajian V, Nyberg R (eds).

Rational Manual Therapies. Williams &

Wilkins, Baltimore, MD

Yahia L et al. 1992 Sensory innervation of

human thoracolumbar fascia. Acta

Orthopaedica Scandinavica 63(2):

195–197

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