like to start off by saying I am by no means an expert in PNF or consider myself

a PNF clinician just yet, but I am currently a resident at the PNF residency program in Vallejo, California, where the roots of Maggie Knott and Dr. Kabat ‘s work started in the United States. This write up is simply me sharing what I’ve learned so far from all the incredible PNF instructors here in Vallejo.

Many people think of PNF as a technique for stretching or exercises for the arms and legs in Diagonal 1 (D1)/ Diagonal 2 (D2) patterns. However, PNF is not just stretching using hold relax/contract relax; or just arm and leg patterns like D1 (flex/add/ER)/D2 (Flex/abd/ER), and chops/lifts. Think of PNF as a way of means of feeding the sensorimotor system specific and purposeful proprioceptive information to create a purposeful and functional motor strategy The components of PNF patterns of facilitation were actually the last thing developed by Maggie Knott and Dr. Herman Kabat as a means of tapping into the DEEP stabilizers of the trunk through the limb-trunk interlinking segments of the body, the scapula/pelvis. Just like any exercise/human movement, the PNF arm/leg patterns have to demonstrate/activate dynamic trunk stabilization from start to finish, and if they don’t, then further assessment is required. For example if the limb-trunk interconnecting segments, pelvis or scapula, are not integrated into the trunk than it’s very difficult to expect the limb to be integrated into the trunk. Hence a limb pattern can lead you to further investigate/asses how or if the scapula/pelvis

are integrating into the trunk. Consequently, PNF is not just a technique, it is a SYSTEM that can be used for both a screen (at a basic level), and/or an assessment/evaluation which would then lead to specific and purposeful treatment plan/techniques.

PNF is based on PRINCIPLES that follow movement based areas of study. Areas of study to provide support for PNF are:

1. MOTOR CONTROL: How the brain controls movement

• REFLEX MODEL • HIERARCHICAL/

DEVELOPMENTAL MODEL: How the CNS develops/integrates higher level postures/movements as the CNS matures from a bottoms up direction (from a spinal cord to the cortical level)

• SYSTEMS MODEL

Something that is CRUCIAL to remember is that these three areas of study are not and cannot be exclusive from one another; they are interdependent and feed into each other. How they feed into each other will make more sense as you read on.

I’ll briefly go into each area of study and elaborate just a bit. 1. MOTOR CONTROL Within this area of study there are 3 models that still seem to hold valid from a scientific standpoint:

PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION

Ramez Antoun, PT, DPT

I’d(PNF): A TECHNIQUE OR A SYSTEM?

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• THE REFLEX MODEL:This model is based on Charles Sherrington’s work, a neurophysiologist in the late 1800s and early 1900s, who decerebrated cats (basically removing the cerebral cortex by cutting through the brainstem of animals) and applied a form of afferent stimulus through stretch or some sort of noxious input to the body to see the efferent (motor) output. He found that no matter the stimulus, there would always be a response, a stereotypical muscle response (remember this is after the cerebral cortex was removed). “For Sherrington, reflexes were the building blocks of complex motor behavior. He believed that complex behavior could be explained through the combined action of individual reflexes that were chained together (Sherrington, 1947) (Shumway-Cook, Woolacott 2012). We know that movement can’t be exclusively explained via reflexes, given our conscious mind, but reflexes no doubt have a huge influence on movement behavior. Many of Dr. Kabat’s basic principles for PNF (for example manual contacts/appropriate application of a quick stretch) came from Sherrington’s work and his reflex model.

• H I E R A R C H I C A L /D E V E L O P M E N T A L MODEL:This model starts to get into motor development and comes from the work of Hughlings Jackson, an English physician, who argued that the CNS has higher, middle, lower levels of organizational control. So each successively higher level in the CNS (spinal cord, brainstem, midbrain, cortex) demonstrates control (ability to inhibit) over the level below it. Rudolf Magnus confirmed this by finding that lower level reflexes (that live in the brainstem/spinal cord) were expressed only when cortical centers

were damaged; similar to what is clinically found with patients who have hemiplegia or patients who suffered a traumatic brain injury. As an interesting side note, some of these reflexes can even be expressed in the neurologically intact individual during extreme circumstances/stress as needed for function; think of a Javelin thrower and the ATNR reflex. This model was later used to describe the way humans progressively develop higher levels of motor function. Higher level postures start to become possible as certain reflexes appear and disappear, or in other words, as higher levels of the CNS (midbrain/cortex) start to integrate/modulate the lower level reflexes (brainstem/spinal cord).

The diagram below over simplifies the concept of motor development.

Basically, as humans, if we only had a functioning brainstem/spinal cord level of CNS control, we would be apedal animals (unable to be mobile beings, whether through crawling or walking) and demonstrate primitive reflexes that we wouldn’t be able to control/inhibit. As the CNS matures we start to integrate/inhibit the SC/brainstem level reflexes with the higher level centers like the midbrain and cortex. It is this higher center integration that allows us to

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inhibit lower center reflexes making it possible to attain postures like prone (on our belly) and quadruped (on our hands and knees). According to the neuro-pediatricians of DNS (Dynamic Neuromuscular Stabilization out of Prague in the Czech Republic), attaining the prone position is when the CNS learns and starts to develop purposeful reciprocal motor patterns (think crawling in prone and quadruped) which are prerequisite to bipedal locomotion, aka walking. Reciprocal locomotion starts in rolling and the prone position, where we learn how to crawl.

Think of reciprocal locomotion like this: the L arm and R leg are doing the same action (i.e propelling us forward while supporting our body like the baby crawling in the bottom right picture) while the R arm and L leg are doing the equal and opposite action, taking a step forward; That is reciprocal patterns for locomotion in a lower level postural position. Walking is nothing more than reciprocal locomotion without the upper extremity weight bearing.

When you walk, if you take a step/swing your L leg forward, your R arm also swings forward; at the same time your R leg and L arm extend behind you (as in the picture below).

For example, a patient with hemiplegia who lacks stability in L stance phase of gait (which could be due to many different reasons) may be treated in supine/sidelying with an extension/abduction lower extremity pattern (emphasizing end range hold), progressed to rolling from sidelying to supine (using same pattern), to prone on elbows/reaching/crawling, to quadruped, to resisted crawling, to tall kneeling, to half kneeling depending on the motoric ability of the patient. Dr. Kabat took this hierarchical/developmental model and worked it into prone/supine progressions, starting with lower level postures and integrating higher level postures based on higher levels of neuroanatomical integration within the CNS. One could argue (based on the newest research in motor learning) that by respecting this model we’re not necessarily creating new motor programs/neuro-motor behaviors, we’re “simply” re-myelinating motor programs that already exist within the CNS, but just haven’t been used since we used them to learn how to walk the first time.

• SYSTEMS MODEL:Back in the early 1900s Nicolai Bernstein, a Russian scientist, looked at the nervous system in a whole new way. He said: “You can’t understand the neural control of movement without understanding the characteristics of

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the system you are moving and the internal and external forces acting on the body (Bernstein, 1967)” (Shumwaycook-Woollacott 2012). He considered the body as a mechanical system that was subject to two forces:

1. EXTERNAL FORCES: • Think gravity and the environment

2. INTERNAL FORCES a. Musculoskeletal system b. Neurological system

Think of the musculoskeletal system as the elastic & plastic properties of the connective/soft tissue. Think of the neurological system as the already learned/automatic motor strategies from past experiences that are engraved in that individual’s CNS. Please understand that this is an oversimplification of the systems model, because truly there are way more than just two internal forces acting on our mechanical system such as the cardiorespiratory & vestibular system, emotions, intellect, etc.

So, Bernstein realized that this mechanical system (our bodies) leaves us with a significant problem when it comes to controlling movement, called the “Degrees of Freedom” problem. Think of “degrees of freedom” as the number of joints and all of their available range that your body has to control. Think about how many joints we are born with; all of which can freely move in various planes of motion (flexion, extension, rotation). As infants we’re born with all the mobility (“Degrees of freedom”) we could possibly need without much stability which exponentially complicates controlling authentic movement. What’s interesting is that we are the only animals that are NOT born with the ability of reciprocal locomotion/the ability to walk, hence we’re stuck on our backs at first. It takes humans about a year to

LEARN how to walk; unless of course the CNS does not develop normally or lacks one of its sensory systems, for example if a baby is born without vision, what motivation does baby have to explore his/her environment and figure out their mobility/stability options to progress through the developmental milestones? What’s even more interesting is that no matter where you are in the world we, as humans, all learn how to walk before the ability to completely understand verbal cues/instruction. There are very characteristic and predictable milestones in which we achieve certain motoric ability (for example, when the CNS is developing “normally” the AVERAGE age babies achieve quadruped is 8-9 months of age). So if we’re born with a ton of MOBILITY (all the available range of motion in all our joints), we then have to learn/earn our STABILITY, in order to then learn how to move with control, let’s call that MOBILITY ON TOP OF STABILITY or CONTROLLED MOBILITY (truly gained by learning how to, with control, move a proximal segment over fixed distal segment). Let’s logically think this through for a second; wouldn’t it make sense to learn how to control all these joints in a synchronized manner first, by starting at a lower level posture (like laying on your back) where the “degrees of freedom” are minimized (aka way less joints to have to control), where you have a very wide base of support with a very low center of mass/center of gravity? Then we can move on to a posture which introduces more “degrees of freedom” (a posture that introduces more joints to be controlled), with a smaller base of support, and a higher center of mass/center of gravity like quadruped, then tall kneeling, then half kneeling then standing. Notice how we would probably have to go through the sequence of mobility, stability, then controlled mobility. Just know that when you’re rehabbing/working with adults they don’t always have

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to go through each and every stage of the developmental sequence (debatable), we just need to find their “weakest link” and find what developmental stage that they don’t demonstrate competency in from a mobility, stability, controlled mobility standpoint. Do you also see how this progression ties in beautifully with the hierarchal/developmental model? If not keep reading.

Bernstein hypothesized that the solution to this “Degrees of Freedom” problem was a hierarchal control system (tying into the previous section) that takes place in the CNS in which higher centers (Sensorimotor Cortex) activate lower centers (subcortical areas) and these subcortical areas activate Synergies, or chains of muscles that are developmentally/neurologically and anatomically designed to work together as a functional unit. Tie this back to the two internal forces that act on our mechanical system: Neurological system: automatic motor behavioral programs that “wire” these synergistic muscles together and the Musculoskeletal system. If you read into Thomas W. Myers’s work and check out his book Anatomy Trains about myofascial connections through the body, you’ll see how he beautifully demonstrates that these muscle synergies are anatomically woven together via our fascial matrix and are pretty much inseparable from a soft tissue stand point. This concept of synergies provides support to the PNF trunk and extremity patterns that were developed by Dr. Kabat based on both anatomical/neuro-programming relationships of synergistic muscle groups working together in harmony with the deep trunk stabilizers. Bernstein also believed that these stereotypical muscle chains/synergies working together as a functional unit, provide us with 3 categories of movement that are crucial for human function and they are: Locomotor, Postural,

and Respiratory synergies.“Newer views of synergies are saying that a muscle can belong to multiple synergies; in addition, an individual muscle has a unique contribution to each synergy. Finally, the total activation of a muscle is dependent on both the simultaneous activation of multiple synergies containing that muscle and the relative contribution of that muscle within each of these synergies” (Shumway-Cook and Woollacott 2012). Dr, Charles Edward Beevor an English neurologist and anatomist simply compliments the past quote with his axiom “The brain does not know muscles, only movements.” So in terms of movement and motor control, why do we insist on testing and exercising muscles in isolation? It seems to make more sense to test and exercise muscles utilizing movement patterns that require the synchronization of synergistic chains of muscles that are already neurologically hardwired (in our DNA) and anatomically connected to function as a team while the body is in various position (Could Manual Pattern Testing be a supplement to Manual Muscle Testing in the future?). Let’s use an example of training glut medius from two different perspectives: glut medius training using isolation with clam shells vs. glut med training using movement patterns/synergies that involve glut medius as part of the team to achieve movement in various positions. Let’s first agree that in various loaded positions like asymmetrical stance (In-line lunge, hurdle step, single leg stance) and symmetrical stance (squat/sit to stand, deadlifting) Glut med activation is required in various synergistic patterns and in different muscle and joint positions. What’s very convenient is that the same synergistic patterns (which all incorporate glut med) utilized in loaded asymmetrical and loaded symmetrical stance can also be replicated in lower level unloaded or loaded positions (asymmetrical: active

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straight leg raise, rolling, quadruped with one leg in extension, half kneeling. Symmetrical: quadruped, push up, tall kneeling). So although we can activate glut medius in isolation with clam shells and show, through EMG studies, that glut medius is lit up like a christmas tree; repetitive isolated concentric and eccentric contractions of the glut med do not allow glut medius to learn how to coordinate its activation/timing of activation with its synergistic partners during loaded asymmetrical and symmetrical positions. Also as Gray Cook would explain that doing 3 sets of 10 reps of repetitive concentric/eccentric contractions is considered strength training which is applied to muscles categorized as stabilizers a lot in the movement profession. But stabilizers’ primary role is to activate extremely fast (before movement occurs) to keep a joint in good alignment and STABILIZE the joint before and while the bigger mover muscles activate and move the joint. So stabilizers don’t really need to be all that isotonically strong as much as they need to learn how to reflexively activate prior to and during movement in concert with other muscles in that synergy in order to provide authentic dynamic stabilization while the joint is kept in it’s ideal position (maintaining the joint’s instantaneous axis of rotation). Gray Cook’s quote: “Does exercising glut medius alone exercise the pattern or does exercising the pattern exercise glut medius?” seems to correlate with Dr. Kabat’s quote: “The nervous system is continuous throughout its extent- there are no isolated parts.” Gray Cook and Dr. Herman Kabat would’ve gotten along pretty well.

So although all you can see sometimes is the tip of the iceberg of PNF (that is D1/D2, contract relax, chops/lifts); understand that under the surface of the water is where the mass of the iceberg lies and the foundation/

rational/success of PNF application (or ANY system) is driven from a solid understanding of the foundation/principles that were derived from motor control areas of study: THE REFLEX MODEL, HIERARCHICAL/DEVELOPMENTAL MODEL, and THE SYSTEMS MODEL.

For other systems that implement these motor control concepts to Sports medicine and Orthopedic populations I urge you to look into DNS (Dynamic Neuromuscular Stabilization out of Prague in the Czech Republic), SFMA (Selective Functional Movement Assessment) and FMS (Functional Movement Screen).

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References

1. Alder, Susan . PNF in Practice . Third. Springer Medizin Verlag Heidelberg: 2008. Print.

2. Cook, Gray. Movement. Aptos, CA: On Target Publications, 2010. Print.

3. Grzybowski, Terry. “Mobility vs. Stability .” PNF. CA, Vallejo. 1997.

4. Liebenson , Craig . Rehabilitation of the Spine. 2nd. Baltimore : Lippincott Williams & Wilkins, 2007. Print.

5. Myers, Thomas W. Anatomy Trains. 2nd. Churchill Livingstone, 2001. Print.

6. Shumway-Cook, Anne, and Marjorie H. Woollacott. Motor Control: Integrating Research into Clinical Practice. 4th. Baltimore, MD: Lippincott Williams & Wilkins , 2012. Print

7. Kobesova , Alena. “Dynamic Neuromuscular Stabilization according to Kolar Level A.” Athlete’s Performance . Arizona , Phoenix . 2012

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