Primary Reflexes and Structural Typology

by Robert Schleip

"You must remember that in appreciation of a body what you are looking for at
is the relationship between flexors and extensors"
Ida Rolf

This article will describe a neurobiologically oriented structural typology. Before doing so I will relate it to other already existing typologies in our field.

Currently there exist two structural typologies in the field of structural integration which have been published by their originators: the Sultan external/internal model and the Flury model of his 4 types (regular external/locked knee internal/regular internal/symmetrical external). Both systems have served as very valuable tools to differentiate our perception for structural differences and more differentiated working options. Jan Sultan's model (as published in the Notes on S.I. 86/1) uses femur rotation as the key indicator and is based on the craniosacral breathing mechanism as the theoretical driving force. Hans Flury´s typology (Notes on S.I., 89/1 & 90/1) uses pelvis position (shift & tilt) as the crucial key factor and the effect of gravity in the standing position on the tissues of the client as the theoretical driving force for his described structural differentiation.

In working with both systems for several years now I have found GREAT insight and practical usefulness in both of them. The only theoretical difficulties or shortcomings those two models had for me can be briefly described:

  • The assumption of Sultan's model that the very minute craniosacral breathing mechanism would be the primary driving force for such gross changes like pelvic tilt, chronic spinal extension, ribcage inflation, etc. is difficult to imagine. Compared with respiratory breathing the craniosacral pulsation is supposed to be at least hundred times smaller. Both movement cycles are of roughly similar frequency, and of course steady repetitions of small forces can eventually move mountains. But it still would seem more likely that the respiratory breathing pattern would influence ribcage and trunk patterns more than its hundred times smaller companion.
  • Other difficult items to understand in Sultan's model are the positions of the feet. Most medical statistics report a higher correlation of valgus feet with valgus knees (pronated foot with X-legs) and of pes varus and genu varus (supinated feet and O-legs) as compared with their opposite combination patterns. And this seems to fit to most bodyworkers experience. In contrast to this Sultan's structural theory claims the combination of pes varus with genu valgus and of pes valgus with genu varus as the "congruent" patterns. This seems to be not explainable with gravity (The "congruent" combination patterns of knee and ankle position of Sultan's model actually go against the gravitational logic as outlined in Fig.7) but mainly from Sultan's proposed energetic "transmission lines" (which are still hard to understand in clear anatomical or physical terms for me). ( E.g. it seems clear that with an internally rotated femur pattern the daily movement of walking forward would support a more powerful myofascial development and tonus on the lateral quadriceps and the medial hamstrings. This fits to the energetic transmission lines of an internal type. But looked at kinesiologically this seems to be a secondary result and not a cause of the femur rotation. Since neither hamstrings nor quadriceps are effective hipjoint-rotators in standing, decreasing the tonus on those fibers would still have no mechanical effect on the femur rotation. )
  • Flury´s system seems to assume that the force of gravity which is influencing the body structure over time finds the clients body most often in the standing position with the pelvis shifted and tilted in her or his particular Rolfing standing pose pattern. Flury´s theory would be the appropriate model to understand the long-term gravitational effects in the honorary soldiers who are standing in a modified Rolfing stance all day in front of London´s Buckingham Palace. But for the majority of my current clients sitting is much more common than standing. And: the habitual pelvis position in sitting is generally quite different than in standing. E.g. clients with a clear anterior pelvic tilt pattern in standing often sit more posteriorly tilted than those with a less anterior pelvic tilt in standing. Then the resulting long-term effect of gravity on them is of course quite different than Flury´s typology describes.
  • Additionally Flury´s description of "primary" and "secondary shortness" doesn't seem to differentiate between myofascial length and myofascial tonus enough. But length and tonus are very different features. Depending on joint position and gravitational forces a myofascial unit can be in either one of those four combination patterns: short & soft, short & tight, long & soft, or long & tight. So what Flury calls "primary shortness" (e.g. in the front of the chest in clients with a kyphotic ribcage pattern in standing, or for example in the hipjoint flexors in an internal type person) could be either one of the following two very different structural patterns:
    1. In some clients those shortened myofascial structures are very relaxed or one could say they are simply collapsed into this position without a tightening of those myofascial connections (i.e. short distance & low tonus). One can recognize this often quite easily, that when lying down those shortened connections lengthen without any resistance. E.g. then the kyphotic ribcage pattern or the pelvic tilt changes by itself as soon as they lie down.
    2. This is of course structurally quite different to those people where the kyphotic ribcage pattern or the lumbar lordosis shows up also when they lie down comfortably relaxed on their back on an even table. In those people the shortened fibers are chronically actively contracted (i.e. short distance & high tonus).

Since those two situations are very different it makes sense to treat them also with different manual working approaches as will be shown later in this article.

All typologies - specially if they are very congruent or brilliant - have a danger of narrowing our perception to certain features and to ignore all other possible perceptions. Gregory Bateson once said: "all typologies are misleading". This seems to be specially the case the more one is convinced or sure of a particular model, or where the model or its originator is treated with severe emotional respect. When a model is taken more light-heartedly, or when one is comfortable to use different even contradictory models as temporary stimulation for ones perception, then they tend to be much more useful and even powerful devices.

Gladly for us neither one of these two typologies has become ‘successful’ enough to have seduced us as a group to develop a missionary tunnel vision perspective. This seems to be an appropriate context to introduce another typology as an additional stimulation for our school. If this new typology helps us to avoid taking any of the existing models too much as a dogma, then it will give us the advantage of having more options of looking and of understanding the various factors that determine individual human structures.

This new model is oriented at understanding the neurobiological components of individual human structures. It is based on the following three premises:

1) A dynamic definition of structure

As opposed to a static definition of structure (geometrical arrangement of segments of a body in a certain rare standing pose) this definition looks at the most common movement habits of a person. Posture (e.g. in sitting or standing) is seen as movement too.

This concept of human structure goes along with the understanding of the Nobel prize winner Ludwig van Bertalanffy who was strongly opposed to applying a clear-cut division line between structure and function (as is usually appropriate in mechanical systems like a machine) to biological systems, when he wrote:

"This separation between a pre-established structure and processes occurring in that structure does not apply to living organisms. For the organism is the expression of an everlasting orderly process ... What is described in morphology as organic forms and structures, is in reality a momentary cross-section through a spatio-temporal pattern. What are called structures are slow patterns of long duration, functions are quick processes of short duration."

L.v.Bertalanffy, Problems of Life", 1952.

In the proposed neurobiological model for Structural Integration "structure" then is defined as the most permanent movement habits of a person at this period of their life. So the difference between function (like shrugging the shoulders for a second as a communicative gesture) and structure (like a chronic tendency to almost always tighten the pelvic floor since early childhood) is just a difference in time, or the question: "how permanent or how repetitive or how common is this feature in this persons daily average body usage?"

For the static definition of structure it is possible to give some structural evaluation just from looking at a static photograph. With the proposed dynamic structure definition one needs to see the person in several different aspects (e.g. walking, standing, sitting down, lying prone/supine, etc.) for a visual structural evaluation. (But it might be possible for a very good computer to recognize structure (based on the proposed dynamic definition of structure) by analyzing the visual data of a person seen walking at a distance and by finding the most permanent or repetitive features in his or her movements. )

2) The primacy of the nervous system in motor co-ordination.

The bones usually don't do anything which the muscles don't tell them to do. And the muscles usually don't do anything which the nervous system is not telling them to do. That means for the most part movement (and postural) habits are directed from the nervous system. (As pointed out earlier studies of bodies under anesthesia have shown two interesting results for us Rolfers: first, that most of the structurally important myofascial restrictions are temporarily gone under anesthesia; and second, that the tissue of anaesthetized bodies doesn't respond much to Rolfing manipulation work. Both findings support this second assumption of the primacy of the nervous system in our work.)

3) A developmentally oriented view of the evolution of individual structure.

Most of the characteristic movement habits (and postural habits) of a person that allow us to distinguish that person from others (e.g. when seeing someone from far away and after not having seen that person for a long time) have been gradually developed over their lifetime, with most of the development happening in their early years (before the end of puberty). Therefor it is useful to look at those factors that influence motor organization in the early individual developmental process and which can lead to structural differences between people in later life. This developmental viewpoint will pay special interest to common evolutionary (phylogenetic) as well as embryological (ontogenetic) processes.

This model looks at two primary reaction patterns that are also sometimes called reflexes: the ´Landau Reflex´ as basis for a chronic shortening of most genetic extensor muscles and the ´Startle Reflex´ as a basis for a chronic shortening of most genetic flexor muscles. It is suggested that the two mentioned reaction patterns involving those two opposing sets of muscles - the genetic extensors and the genetic flexors - can be understood as important forces influencing adult human structures.

To explain the terms ´genetic extensors´ and ´genetic flexors´ a brief look at our embryological development is helpful.

Fig.1 shows the position of a 5 weeks old embryo with all extensors on the dorsal side and the flexors on the ventral side. As one can see our legs first appear as buds coming out of the lateral sides. At around 6 weeks the elbow and knee joints are formed. Then the elbow joint fold as well as the knee fold are facing ventral (!) with all flexors facing that side too. This is the same situation in adult reptiles and amphibians who have all their flexor muscles facing ventrally. In mammals - and in human embryonic development after the 7th week - the legs have rotated medially; and even later in we bipeds the original flexors of the leg are now arranged on the dorsal side of the leg as well as the plantar surface of the foot.  

The genetic extensors and genetic flexors are designed as very different types of muscles; different neurologically, functionally, and morphologically. They are enervated from different areas of the spinal cord. The extensors are dominantly equipped with slow twitch fibers (type I or ´slow oxidative fibers which are called tonic fibers and are usually quite thin). They don't tire so fast, and they are more ´dark meat´ colored. Whereas the flexors have a lot of fast twitch fibers (type IIb or ´fast glycolytic´or tonic fibers) which are usually much thicker and can act fast but also tire fast and which are more ´light meat´ colored. ( There are exemptions to this simple rule, like the presence of a high amount of tonic fibers in the soleus in humans. It is believed that most muscles have a genetically determined tendency towards growing more phasic or more tonic fibers, but exercise and daily usage have been proven to influence them too.)

Genetic Extensor Muscles

Genetic Flexor Muscles

 primflex2 PrimRefl3 
  • mainly tonic muscles
    with a lot of slow twitch fibers
    (Type I or ´slow-oxidative´
    fibers), red meat color
  • enervated from ventral part of
    anterior horn of spinal cord
  • originally arranged dorsally
  • now located on dorsal side of trunk
    and arms (in anatomical position),
    on ventral leg and plantar side of foot
  • mainly phasic muscles
    with a lot of fast twitch fibers
    (Type IIb or ´fast glycolytic ´
    fibers), white meat color
  • enervated from dorsal part of
    anterior horn of spinal cord
  • originally arranged ventrally
  • now located on ventral side of trunk & arms, on dorsal leg and dorsal side of foot.

A simple way for grouping all muscles of the human body into the two categories is: Genetic Extensors are those muscles that are enervated either by a dorsal primary ramus (i.e. all erector spinae) or by a dorsal ramus of the plexi. The latter are all those enervated by one of the following six nerve supplies:

  1. common peroneal nerve
  2. gluteal nerves
  3. femoral nerve
  4. radial nerve
  5. axillary nerve
  6. posterior cord of brachial plexus.

All other muscles can be considered to belong to the Genetic Flexors.Very useful charts about this correlation can be found in 'Muscles, Testing and Function', F.P.Kendall, E.Kendall Mc Creary, P.G.Provance, 4th Edition, Baltimore 1993, pages 389-394. )

Here's a list of muscle groupings into those two categories:



  • Erector spinae (incl. head and neck extensors) plus levatores costarum.


  • All arm muscles enervated by the radial nerve (e.g. triceps, brachioradialis, supinator, all extensor muscles of lower arm, wrist and hand)
  • All muscles enervated by the common peroneal nerve (i.e. the extensor compartment of the lower leg, plus peronealsplus ext.dig.brevis The peroneals were displaced secondarily in the evolutionary process. Originally they passed anterior of the malleoli, as can still be seen in predators.), quadriceps & sartorius (The sartorius is a good example for functional changes of a muscle in the evolutionary process. In us humans it functions now clearly as a flexor of the hipjoint as well as the knee joint. But from its ontogeny it is an extensor, just like the quadriceps, and still shares the same (femoral nerve) enervation with it.)
  • Subscap., latissimus & teres major.


  • Trapezius pars descendens
  • Scalenes
  • Deltoid
  • All muscles enervated by the gluteal nerves: glut.max,, and tensor f.l.
  • The deep six rotators of the hipjoint (except the obt.ext.)
  • Levator ani (It used to be believed in our school that the muscle group to which the levator ani is most closely connected would be the adductors. Anatomically this doesn't make much sense since the adductors attach to the lateral side of the ramus and the pelvic floor quite far away from it to the medial side of the ramus. In fact the levator ani is fascially much more closely connected with the deep hip rotators via the obturator internus and the piriformis. It also shares the common enervation from the sacral plexus with this muscle group.)




  • Rectus abdominis with infrahyoids (and sternalis, if present) (Originally there used to be one long ventral flexor column from the floor of the mouth down to the top of the pelvis (incl. the tissue to become the tongue). Of this the thoracal part mostly disappears in later embryonic development. See: Langman, J., Medical Embryology, Chapt.10 )


  • All muscles enervated by the musculocutaneus, median or ulnar nerve (i.e. all other arm and hand muscles besides those enervated by the radial nerve)
  • All foot muscles enervated by the tibial nerve (triceps surae, the three deep flexors in the lower leg, as well as all intrinsic foot muscles - except the ext.dig.brev)
  • The three hamstrings (except for the short head of the biceps fem.) plus the portion of adductor magnus which inserts into tuberculum adductorum. (The long part of the adductor magnus (i.e. the part inserting into the tuberculum adductorium) is actually designed to work together with the medial hamstrings - neurologically, functionally, and anatomically because of the common epimysium in this area. That's why it doesn't make much sense when it is sometimes claimed by Rolfers that they "separate" the adductor magnus tissue from the hamstrings. )
  • The prevertebral neck muscles and subclavius
  • The upper part of the pect.major
  • The iliopsoas
  • The lateral bellywall (obl.ext., & transv.abd) and the internal intercostals with the transversus throracis ( Note that the internal intercostals (which are expiratory assist muscles) are arranged more ventrally than the external intercostals which tend to be more focused in the back.)


  • The adductors (including the adductor magnus with the portion inserting on the linea aspera) (A cross section of the thigh with the lateral and medial intermuscular septi dividing the leg into genetic flexors and genetic extensors shows quite convincingly that the adductors belong to the flexor compartment. Only for the pectineus who shares its additional femoral nerve enervation with the quadriceps it is not so clear to which genetic group it belongs more closely.) and the obturator externus
  • The serratus anterior
  • Inferior part of pectoralis major, and pectoralis minor.
  • Superior part of trapezius, and the sternocleidomastoideus ( Trapezius and s.c.m. used to be one single muscle in early embryonic life, which then split laterally into those two parts. They are still enervated by the same (11th cranial) nerve. )

Short Extensor Pattern

When holding a six month old baby unexpectedly into open space only supported with its belly on your hand, it will most likely react with the so-called "Landau Reflex", which is an active shortening of most genetic extensor muscles (See Fig.3).


Fig. 3:  4 month old baby without  (above) and 6 month old baby with 'Landau Reflex' (below)

It lifts its head, arcs its trunk backwards and extends the legs. This does not happen normally with much younger babies and therefore this reflex reaction is used as a standard neurological test for the development of the baby.

Already at about 3 months a healthy baby learns to use the extensors of the neck and upper back to lift its head when lying prone in order to more actively meet the outside world around. This seems to be a genetically programmed function also as a first element for the functions of walking and standing. Learning to arc the back with the lower erector spinae comes later, usually about 5 months. Then the baby is usually also able to lift its legs and arms as well as arcing the whole back, which is the basis of the Landau Reflex as an important gravitational response.

In some people this muscular pattern becomes a chronic habit which then shapes their overall posture and movement patterns. Thomas Hanna describes this reflex as "Green Light Reflex" to indicate the psychological state of preparedness or readiness for active interaction with the environment which accompanies this Landau Reflex. He writes "The Green Light reflex is assertive; its function is action." ( Thomas Hanna, Somatics, p.65 ) If somebody's posture is dominantly shaped by this reflex - or one could say by this attitude ( The German word "Haltung" beautifully relates to both aspects; it means "posture/tension pattern" as well as "attitude" in English language ) - it will become a chronic feature and show in a shortening of the genetic extensor muscles.

The Short Extensor Patternin standing looks like this:

Short Extensor Pattern

Primary Features:

  • Most clearly the trunk erectors will extend the spine and trunk
  • The trunk extension and shortening of the dorsal muscles of the trunk will tend to support a high chest and inspiration fixated ribcage pattern.
  • A higher tonus of the dorsal musculature of the pelvis than on its ventral side will tend to pull the pelvic bones into a more out flare pattern with narrow tuberosities and a wide diameter in front between the ASIS of both sides.
  • The leg extensors will clearly rotate the femora externally (due to the medial spiraling rotation that the legs underwent in our embryonic life and which the original hip extensor muscles still follow)


Secondary Features:( The term does not relate to secondary flexor muscles above. It simply indicates that those features are not as obligatory or common than the above primary ones (but they still tend to be more common than their opposites in this structural type).)

  • In many cases the short hipjoint-extensors will pull the pelvis into an extended hipjoint pattern (i.e. posterior pelvic tilt). (What's happening to the lumbars and pelvis in the upright standing position depends on which of the following two extensor groups acts more powerful: the hip extensors or the lumbar erector spinae. In the majority of the Short Extensor Pattern people the shortening of the strong hip extensors (which was very useful in the childhood task of "standing up" into full biped stance and which seems to be aided by the "Let's go for it" -attitude of this reflex pattern) shapes the pelvic tilt more than the tonus of the lumbar erectors. But this is not always the case and therefor this feature is not as uniform as the trunk extension for this reflex type. That the lumbar erectors are normally not as significant for the standing posture as the hip extensors might be supported by the anatomical fact that there are not many contractile muscle fibers in the lumbar area of the erector spinae. Besides the multifidus most of the erector spinae muscles are totally white or tendinous in this area; which is of course very different in higher areas of the spine where we find a lot of red muscle fibers of all the really powerful erector spinae muscles.)
  • The shoulder blades will often be drawn backwards. (The muscles retracting the scapula developed out of the early extensor tissue of the myotomes of the arm. They are not as clearly genetic extensors as the erector spinae, but they are more closely associated with the genetic extensors than with the flexors.)
  • The extensors of the lower leg and foot will tend to increase a pronated foot pattern.
  • Often the high tonus of the deltoids will abduct the arms chronically.
  • Often the high tonus of subcap/lats/teres maj. will rotate the humerus internally.
  • Besides ABduction of the arms there is often also a tendency for increased ABduction of the legs (triggered by high tonus of the leg abductors).


The Short Extensor Pattern puts people usually more upright. This puts them in a more economical position than most random structures. Additionally the genetic extensors are much better equipped for chronic work than the flexors since they are dominantly composed of slow oxidative fibers. Therefore one could expect that those people don't seem to be as tired as the Short Flexor types. This might be aided by the bigger vital capacity in breathing which tends to be able to supply more oxygen for the brain and body. The underlying chronic attitude of "being ready for action" will often be expressed in a more extroverted personality (but of course not always, since other factors might influence this too). A recently published study showed that this posture tends to increase people's sense of self worth or how proud they feel about themselves (Strack, F., Journal of Personality and Social Psychology, 1993. In this brilliant double blind study the participants were unknowingly induced to assume a collapsed or upright posture just by the respective arrangement of furniture. Simultaneously they were given the (wrong!) information that they had just achieved unusually high grades at a mental text just done before. The upright sitting "winners" reported in their questionnaires that they felt very proud about their achievements; whereas the slumped sitting winners were not so much impressed about their achievements.) . In the extreme - when the extensors are chronically severely contracted - people can become stiff and rigid, like in what Ida Rolf called the classical military posture (see Fig.4.


The Short Flexor Pattern

When frightening a mammal with a sudden loud sound or sudden painful stimulus it will show a "Startle Reflex" which has been researched extensively (and often painfully) in scientific laboratory studies. Robert Eaton´s book "Neural Mechanisms of Startle Behavior" (1984 Plenum Press, New York ) describes several studies showing a quite uniform muscular reflex pattern in mammals, which always involves a dominance of genetic flexor contraction. ( Although sometimes an extension of the front and hind limbs may occur in some mammals (e.g. in rats and guinea pigs). But even then it is usually followed by a generalized flexion of the whole body into a "hunched position". The probability of this extensor involvement is higher after voluntary or ongoing extension. I also found it interesting to note that even in those rats, "as habituation proceeds, extension seems to drop out leaving mostly flexion" (Eaton, p.293). )

Fig.5 shows how a human embryo reacts to sudden painful stimulation by curling up more. 


High-speed photography of adult humans during for example a sudden loud noise reveals the following uniform pattern (see Fig.6): 


  • After an initial facial reaction by the jaw and eyes (after already 14 - 20 msecs)
  • the shoulders come up via the upper fibers of the trapezius and the head moves forward (25-40 msecs).
  • Next thing is a bending of the elbows (60 msecs)
  • followed by contraction of the abdomen and finally bending of the knees (145-400 msecs).

It is suggested that a chronic Short Flexor Pattern is often associated with this Startle Reflex as a habitual neuromuscular pattern. Taking the anatomy of the genetic flexors into account the Short Flexor Pattern will look like this:

Short FLEXOR Pattern

Primary Features:

  • It is characterized most clearly by a trunk flexion or kyphotic ribcage pattern
  • The ribs will be in a chronic expiration pattern with a collapsed or sunken chest.
  • The femora will be less rotated externally.
  • The shoulder blades will be drawn forward by the pectoralis major and minor in front.
  • The pelvis will be more often in an inflare pattern with a narrow diameter between both ASIS in front and wide tuberosities in the back.

Secondary Features:

  • In most cases the hipjoint flexors will tend to tilt the pelvis anterior.
  • The lower leg and foot flexors will tend to supinate the foot (high arch)
  • The upper portion of the trapezius will elevate the shoulders.
  • Legs and arms will tend to be more in an ADducted position.


Let's look at the knee positions in terms of genu valgus (X-legs) and genu varus (O-legs), which are defined anatomically by a shorter distance between femur and lower leg along the medial side (varus) or lateral side (valgus). ( Some bodywork practitioners tend to believe that X-legs are caused by short adductors and O-legs by short abductors. But this doesn't hold much ground when one tests this by moving the leg in the lying position; since then it is clear that adduction or abduction of the thigh doesn't influence the X- or O-leg pattern of the knees.) From their history (i.e. medial rotation of the leg in embryonic life) it is quite clear that the medial leg muscles of the thigh and lower leg today are more closely related with the original flexors. They used to be more in the front with the knee flexors and they still tend to act more like flexor type muscles. Whereas the lateral leg muscles used to be more in the back and are more closely related with the original extensors. In a Short Flexor Pattern the increased tension between thigh and lower leg along their medial connections will over time tend to shift the knee joint towards varus (O-legs). This will also be supported in standing and walking by the increased gravitational compression across the medial side of the knee because of the support of the supinated foot pattern underneath (see Fig.7). Whereas in the Short Extensor Pattern the increased tension along the lateral connection of lower leg and femur together with the pronated foot support underneath will lead more often toward the valgus (X-)leg pattern of the knees. 


The psychological and energetic tendencies of Short Flexors are best described by Ida Rolf: "There is another factor in upright stance besides evolution. This factor makes Feldenkrais candidate for the title of a really intuitive researcher. He saw that negative emotion strengthens flexors. My recognition out of my own life is such that such an overwhelming amount of emotional experience is negative. And when you experience negative emotion, you respond with a flexor every time - you flex, always you are flexing ... Feldenkrais called attention of the fact that all negative emotional expressions are accompanied by a shortening of flexor muscles. The energy in a chronically flexed body has to work just to hold up; the man continuously has to add energy to that body to keep it going. Such chronic flexion gives a feeling of ´depression´." (Ida Rolf Talks, p.133-134) When studying Feldenkrais´ original description in ´Body and Mature Behavior´ we see that he calls this Short Flexor pattern "the body pattern of anxiety". Besides a contraction of flexors (especially of the abdominal region) he described for this pattern an "inhibition of the antagonistic extensors" as well as a "halt in breathing". ( p.83.94)

What moved Ida Rolf to describe the underlying neurology of Short Flexor people with this much wider term "negative emotions" - compared with Feldenkrais´ more specific term "anxiety"? I suspect that she felt that there are also other emotional reaction mechanisms besides the startle reflex that can be a neurological basis for this pattern. In my experience it is often useful to differentiate two types within the Short Flexors: a contracted and a collapsed type. In the contracted type the flexor muscles are not only shortened but also tight (short distance & high tonus). In lying supine on a table one can usually find a lot of free space behind their lower neck, their shoulders, and often also behind their lumbars. They have very little inter segmental mobility of their ribcage and fit probably best into Feldenkrais´ description of a chronic "pattern of anxiety".

Opposed to those are Short Flexor people in which the flexor muscles are not actively tightened but are just collapsed (short distance & low tonus). Like in the contracted type the antagonistic extensor muscles of the trunk are lengthened and - because of the harder work against gravity than in a more upright posture - tightened in standing (i.e. long distance & high tonus). When lying on a table the thoracic kyphosis disappears easily and their ribcage still has a lot of mobility. I commonly call this version ´Short Flexor Collapse type´; but it would have also been possible to call it ´Long Extensor type´. I suspect that this muscular pattern is not so closely related to the anxiety pattern of the startle reflex but to a neurobiological feature described as "Postural Collapse". Postural Collapse has been studied extensively as a typical primate reaction to early maternal deprivation. ( for example by Martin Reid of the Univ. of Colorado Medical Center. But there have been also several other studies in which they separated young chimpanzees from their mothers to study postural and other effects of maternal deprivation on young chimpanzees.) They found again and again that an early separation of young chimpanzees from their mothers (e.g. by a glass partition in the cage) would soon lead to this feature of ´Postural Collapse´ (plus other metabolic and neural changes). See Fig.8. (Drawings for this article by Marianna Pavlidou. Some of them were inspired by already published illustrations: Fig.3 by T.Hanna, Somatics, page 64; Fig.4 by D.Johnson, The Protean Body, p.78; Fig. 6 by Eaton, Neural Mechanisms of Startle Behaviour, p.290; Fig. 8 by a video tape titled "A Touch of Sensitivity" by the National Science Foundation, BBC1980.) This seems to be typical for mammals and specially for primates. I speculate that such a trauma of not having got enough emotional/tactile "nourishment" might often be the basis for this collapsed version of the Short Flexor pattern. 


So looked at closer this neurological model could be seen as three different types related to three different primary reaction patterns: Short Extensor type (based on a Landau Reflex), Short Flexor Contraction type (based on the startle reflex), and Short Flexor Collapse type (based on the primate ´Postural Collapse´ reaction). The last two types look very similar from the outside with the same outer form and contour changes, but seen from the inside one can recognize different tension patterns and different neurobiological driving mechanisms underneath them.

Different Manual Working Approaches With Different Neurobiological Body Types:

  • With Short Extensor Pattern people it usually works well to apply more of our traditional "direct technique" or slow but persistent "melting " approach when working with the extensor muscles. This makes sense when taking into account that their trunk extensor muscles are short & tight, so a clear message along the lines of "You fibers, lengthen please!" makes actually sense. Additionally it is specially useful to focus the emotional interaction (tactile, verbal & otherwise) on RELAXATION, to help them to increase their ability to let go instead of being "always prepared for action" without any real pause.
  • In a Short Flexor Pattern it is often useful to not only work with the shortened flexor muscles but also with the extensor muscles of the trunk which are long but tight (or at least tired), in order to seduce them to shorten more effectively. But here a traditional melting work along the lines of "Lengthen please" does usually work not as well with those trunk extensors. It makes more sense to use indirect technique and/or stimulating touch to communicate something like "Hey nervous system, please re-evaluate what you are doing right here with those joints. Maybe you want to change something or be more present here". Another way to put it is to ´VITALIZE those myofascial tissues more. You want to influence those muscle fibers so they shorten (and not lengthen!) more in order to be able to work less hard.
  • With a Short Flexors Contraction Pattern it is additionally advised to do some "lengthening work" on the shortened flexors. But since those muscles don't contain as many Golgi receptors compared with genetic extensor fibers I suggest to address them additionally with indirect technique besides with our traditional direct Golgi tissue stretch type of manipulation. Emotionally it is often good to focus on "SAFETY" in the interactions with the client in order to give new options away from any anxiety pattern underlying the startle reflex mechanism.
  • In a Short Flexors Collapse Pattern it often works best to focus more on stimulation and vitalization of their WHOLE neuromuscular system (instead of getting too much focused in detailed structural logic in a search for any chronically contracted tissues) It often works well to be aware of the nourishing factor of human touch when looking for ways how to bring "more life" back into their system, and to use that tool as effectively as possible. Sometimes this might include giving strong and vigorously stimulating touch in order to achieve this. Active client movement participation also contributes to this very well. So besides subtle micromovement participation I often involve them in participating with more active movements, where they stretch, or move against my resistance while we work. Also postural education works very well and can often do wonders with those types, since there are no chronic tissue restrictions to overcome.


It is hoped that this model helps to stimulate your perception to take into account more neurobiological factors involved in human structure. The author cannot take much credit for the development of this "third model", since basically all elements have been described before (mostly by Sultan, Hanna, Feldenkrais). When comparing the above description of the Short Extensor type and the Short Flexor types with the geometrical description of the two Sultan types it is obvious that there are about 80% congruence; i.e. the Short Extensor type corresponds closely to the Sultan external and the Short Flexors to the internal. The main feature which is clearly different are the lower legs and feet. Therefor it is justified to give most credit to Jan Sultan for the refined development of his model underlying this newly proposed typology as a solid and most crucial foundation. It is further obvious that Sultan's model is based on an enormous amount of clinical experience. It would have been possible to present this new neurobiological model just as a modification of the Sultan model, since it consists basically of his descriptions minus the lower legs & feet, minus the craniosacral driving mechanism, and minus the energetic transmission lines. But since especially the last two items might be crucial factors of Sultan's model, this would have not been very appropriate or even respectful. Therefore I chose to present the above article as a "new" way to look at structural differences between people.

A major difference of this model to both the Sultan and the Flury model is that the two described typologies are not exclusive of one another. Sometimes the two reflex patterns Short Extensor and Short Flexor Contraction can overlay each other, sometimes even in the same body segment. The poor person's ribcage is then not only chronically tightened from the back but also from the front. ( Whereas the Short Flexor Collapse pattern and the Short Extensor pattern would be seen as antagonistic.)

Key indicator for the reflex patterns in not the pelvis position in standing (like in Flury´s model) nor the femur rotation (like in Sultan's), but the tonus balance between trunk-flexors and trunk-extensors, specially around the ribcage. In Short Extensors the main mobility-limiting elements for the ribcage are the tight extensors in the back; in Short Flexors Contraction types it is the tight flexors in the front; and with the Short Flexors Collapse types there is free trunk mobility with a sunken and collapsed (but not tightened) chest in front.

It is clear that postural typologies are arbitrary ways to divide a continuum. One can easily divide the cake into two slices, or twelve, depending how many distinctions one wants to make. The proposed way of eating the cake in two big portions (and calling one of them Short Extensor type and the other Short Flexor type) and then eating the second one of those portions in two different styles is suggested as a useful tool to include more neurobiological factors into our work. But there are other ways to divide the cake. One of them was suggested by the American humorist Ogden Nash who once said:

"There are two kinds of people:
those that believe that there are two kinds of people,
and those that don't."

The Rolf Recipe as a Flexor-Extensor Wave


The Rolf Recipe can be understood as a wave between genetic flexors and extensors.

It is possible that Ida Rolf was consciously aware of this aspect (see the quote above). Yet it is also possible that this mainly served as a subconscious and intuitive background for her in the creation of the recipe (similar like many people intuitively feel a similarity between the ‘softer’ genetic flexor tissues in their arms, legs and belly -as opposed to their more ‘stringy’ extensors -even if they don’t know much about anatomy or embryology).

First Triangle (Superficial Sessions)

Session 1:        Flexors (mainly work on front of thorax, yet curiously also on hamstrings)

Session 2:        Extensors (mainly work on front of legs, plus on erector spinae)

Session 3:        Integration, synthesis (relating front to back)

Middle Triangle (Core Sessions)

Session 4&5:    Flexors (abdomen, chest, adductors). Ida Rolf often suggested to see 4&5 as one session.

Session 6:        Extensors (back of legs, hip rotators, erector spinae)

Session 7:        Integration, synthesis

Third Triangle (Integrating Sessions)

Session 8:        Flexors (all main flexors. Including healthy flexion and pull/curl gestures of client)

Session 9:        Extensors (all main flexors. Including healthy extension and push/reach gestures of client)

Session 10:      Integration, synthesis (contralat. push-pull combinations in crawling, walking, running,



The Flexor - Extensor Typology In a Nutshell

Genetic Extensor Muscles

Genetic Flexor muscles

  • Enervated from a dorsal primary ramus or the dorsal branches of the plexi.
  • Tend to be tonic (slow twitch fibers).
  • Tend to be involved in Landau Reaction
    (Green Light Reflex).

· Enervated from the ventral branches of the plexi.

· Tend to be phasic (fast twitch fibers).

· Tend to be involved in Startle Reaction
(Red Light Reflex).


  • erector spinae (incl. levatores costarum)


  • rectus abdominis & infrahyoids


  • sartorius
  • rectus femoris
  • tensor fasciae latae
  • neck extensors


  • short foot muscles (exc. for the ext.dig. brev.)
  • oblique and transverse abdominals
  • abdominal part of pectoralis major
  • serratus anterior


  • ext.dig.long.& brev., ext. hal. long.
  • peroneals.
  • latissimus, teres maj. & subscapularis
  • deltoid
  • those enervated by the radial nerve
    (e.g. triceps, brachioradialis, supinator, and all extensor muscles of the wrist & hand).


  • the 3 deep flexors of the lower leg (, flex.hal.long., flex.dig.long.)
  • those enervated by the obtur. Nerve (the long adductors plus the obt.ext.)
  • int. intercostals & transv. thoracis
  • pectoralis minor & subclavius
  • sternocleidomastoid

Postural Patterns

Extensor Type

Flexor Type

Primary Features:

  • most clearly: trunk extensors will extend the spine and trunk
  • high chest (inspiration fixated)
  • external femur rotation
  • outflare pelvis shape
    (wide front, narrow tuberosities)
  • AB-duction of arms and legs

Primary Features:

  • most clearly trunk flexion (kyphotic ribcage)
  • ribs in chronic expiration pattern with collapsed chest
  • femur less rotated externally
  • inflare pelvis shape
  • AD-duction of arms and legs

Secondary Features:

  • protraction of scapula
  • hipjoint flexion
  • internal humerus rotation
  • pes valgus (foot pronation)
  • genu valgus (X-legs)

Secondary Features:

  • retraction of scapula
  • hipjoint extension
  • humerus less internally rotated
  • pes varus (foot supination)
  • genu varus (O-legs)



- Jan Sultan, in 'Notes on Structural Integration', 1989/1 (basic foundation of this typology).

- Thomas Hanna: 'Somatics', Addison-Wesley, Reading MA, 1988 (Green Light & Red Light Reflex).

- Robert Eaton: 'Neural Mechanisms of Startle Behavior', Plenum Press, N.Y., 1984 (details about the startle reflex)

- Kendall, Kendall, Wadsworth: 'Muscles, Testing and Function', Baltimore 1971 (muscle enervation charts).

A first draft of this article was published in ROLF LINES, October 1993