Tag: ground force reaction

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Decoding The 5 Primary Kinetic Chains Charts Series: Sacral Stability/Piriformis

*Please note this particular series of blogs will describe each of the four muscles and their relationship to the five principal actions described in the charts of The 5 Primary Kinetic Chain Poster Set I’ve developed.  This is the first in a series of four posts.  You can find the second post on the Iliacus here.

Introduction to the Sacrum:

The sacrum, or sacred bone, is unique in the body. Mystics regard the sacrum as the focal point for kundalini, the spiraling energy that rises from the root through the crown. This triangular shaped bone provides the base of support for the spinal column.

The sacrum articulates with the pelvis through the sacral iliac joint, SIJ. The kinetic energy of ground force reaction moves from the feet engaging the earth, up through the legs, into the pelvis. The energy crosses through the pelvis into the sacrum and up through the axis of the spine. The manner by which the energy moves into and through the axis of the spine defines our ability to respond to ground force reaction.

There are four important muscles that act directly on the sacrum.

Anterior Surface:  piriformis & iliacus

Posterior Surface: multifidus/sacrospinalis & gluteus maximus

These four high level muscles often are not engaged with their task of stabilizing the sacrum through a spectrum of movement.  When we look at the function of these four muscles, and the various movement they are involved in, there is a trend we see in most people’s presentation that are seeking therapeutic intervention.

The anterior surface muscles are often up-regulated. These muscles are over worked and do not respond appropriately. One of the flavors of synergistic dominance is when one group of fibers becomes up-regulated, those dominant fibers then down-regulate the function of that muscle over its spectrum of movement.

The posterior surface muscles are often down-regulated and are not available to respond appropriately to movement.

The relationship of how these four muscles work together in coordination changes over the spectrum of movement. The 5 Primary Kinetic Chains have unique principal actions that inform the sequence of movement.  This series of essays will describe each of the four muscles and their relationship to the five Principal Actions I’ve described in the 5 Primary Kinetic Chains poster set.

Piriformis:

The piriformis is a flat, pyramidal shaped muscle that runs from the anterior surface of the sacrum to the greater trochanter of the femur. The manner by which the muscle fans across the broad surface of the sacrum is somewhat similar to the subscapularis attaching to the scapula. The piriformis is an external rotator of the femur; the subscapularis is an internal rotator of the humerus, thereby making them functional opposites.

Many people have challenges due to the structure and function of their piriformis. Approximately one in 5 of us have piriformis anomalies (Read more here). Those that have this are often grouped into a category of “piriformis syndrome,” a pattern of up-regulated piriformis that irritates and compresses the nerve bundles, the sciatica nerve, that pass through the muscle.

People that have this presentation are often challenged by common movement triggers. Prolonged sitting, driving, and — for some — simply walking, is enough to exacerbate the pressure of the muscle acting on the nerve.

piriformis-1piriformis-2

Concentric Actions of The Piriformis:

Sagittal ~ hip extension & sacral flexion

Coronal ~ hip abduction & sacral downward/upward rotation (limited by SIJ gap)

Transverse ~ hip external rotation & sacral downward/upward rotation on an oblique axis

The Piriformis and The 5 Primary Kinetic Chains:

Intrinsic ~ Breath

The relationship between the piriformis and the pelvic floor is often a good starting point for evaluation. The following two scenarios are common presentations:

Spinal Wave:

The piriformis is a participant in the spinal wave during the breath cycle.

Inhalation Phase:  pelvic floor / eccentric action ~ spine / extension action

Exhalation Phase: pelvic floor / concentric action ~ spine / flexion action

An up-regulated piriformis is the action of the exhalation phase thereby affecting the inhalation phase of the breath.

 Pelvic Floor:

The sacral tuberous ligament, and the obturator internus help make up the extrinsic boundaries of the pelvic floor. The piriformis is a synergist to the obturator internus making it an easily recruitable option for an up-regulated pelvic floor.

Deep Longitudinal ~ Shock Absorption

An up-regulated piriformis interferes with the kinetic wave of shock absorption. The up-regulated piriformis is a bracing strategy for the SIJ. Compression in the SIJ functionally acts as an abutment to the kinetic wave of ground force reaction.

The body’s appropriate response to the kinetic wave of shock absorption is to counter with the push reflex. Imagine stepping off the curb. The hip must descend so that the foot can meet the ground. This is an eccentric action of the quadrates lumborum, the QL. An up-regulated piriformis down-regulates the push reflex.

The peroneal nerve, a division of the sciatic nerve, innervates the subsystem muscles of the deep longitudinal kinetic chain. An up-regulated piriformis that compresses the peroneal nerve will affect the peroneus muscles and the short head of the bicep femoris. When these subsystem muscles are unable to respond appropriately, the compensation is joint compression strategies that will move up the kinetic chain.

Lateral ~ Axial Stability

The gluteus medius, a lateral kinetic chain subsystem muscle, needs to play well with the piriformis. The piriformis is both a synergist and functional opposite to actions of the gluteus medius.

The gluteus medius attaches to the pelvis with a broad fan-like orientation of fibers.  The action includes abduction of the hip, and internal and external rotation of the femur. This is significant because some fibers act as synergists and others act as functional opposites. Often, select fibers of an up-regulated gluteus medius will functionally down-regulate the other fibers. This contributes to an up-regulated piriformis.

The lateral kinetic chain is in contralateral relationship with the anterior spiral kinetic chain: stance / swing. This movement requires stability across the anterior surface of the sacrum. The contralateral iliacus and the piriformis become functional synergists during the swing phase of the gait.

The iliacus and piriformis pictured here are in ipsilateral relationship. When the iliacus and piriformis are in contralateral relationship they create a functional X across the anterior surface of the sacrum.
The iliacus and piriformis pictured here are in ipsilateral relationship. When the iliacus and piriformis are in contralateral relationship they create a functional X across the anterior surface of the sacrum.

Posterior Spiral ~ Generation of Stored Elastic Energy

The coiling of the thoracolumbar fascia acts on the sacrum and the SIJ. The hip is extending and externally rotating. The piriformis is a synergist to the gluteus maximus, a posterior spiral subsystem muscle and sacral stabilizer.

Potentially any muscles in the posterior spiral kinetic chain could be in a synergistic dominance relationship.

Posterior spiral kinetic chain is paired with the contralateral deep longitudinal kinetic chain. The push leads the strike; the piriformi are in an alternating activation.

Anterior Spiral ~ Translation of Stored Elastic energy

The anterior spiral pairs with the contralateral lateral kinetic chain. At the moment when hip extension translates into hip flexion, the ipsilateral iliacus and the piriformis are in functional synergist relationship.

Remote Relationships:

The body starts to look for recruitments to assist an up-regulated and fatigued muscle. One common recruitment pattern is muscles that have similar fibril orientation. The lateral pterigoid is a common jaw remote relationship.

 Manual Therapy Application:

One important aspect of any manual intervention is to ask the body directly if the modality is appropriate. This can be verified by doing a little bit of release.  Go back to the relationship and take notice. Did the response change in a favorable way? If it did, then the release technique was appropriate. If it did not, then the nervous system needs something else to restore the coordination.

There are few strategies I regularly employ when working with an up-regulated piriformis.

Strain Counter Strain:

This is a one of my favorite go to techniques. It is gentle and effective. There is little risk to further irritation of an up-regulated piriformis.

Belted Pelvis:

This active bilateral release can have a dramatic positive effect in the SIJ. The belt puts the SIJ in compression while the bilateral activation of internal/external rotation resets the receptors. The therapist can approach the release in two ways. One is to use feedback pressure to activate the balance between internal and external rotation. The other is to use bilateral pressure on both piriformi to reset the muscle spindles.

Pin and Stretch:

This flossing technique is a mixed bag. It can either be highly effective or over stimulate the nervous system. Ask the body if it is appropriate to the client’s presentation.

Conclusion:

When assessing the players involved with sacral stability, ask if the players can cooperate with each other. Getting all the players back on the same team make for a happy sacrum.

Glossary:

Concentric activation ~ The muscle fibers are shortening; the muscle attachments are moving toward one another.

Eccentric activation ~ The muscle fibers are lengthening; the muscle attachments are moving away from one another.

Synergist ~ Muscles that work together during movement.

Functional Opposite ~ Muscles that work opposite to one another. One muscle is lengthening while the other is shortening.

Up-Regulated ~ An overstimulated muscle that is compensating for other muscle/s that are not participating. Often the muscle will become overworked and fatigued and unable to respond appropriately.

Down-Regulated ~ An under stimulated muscle. The function is impaired and unable to respond appropriately.

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Complementary Movement

The Five Primary Kinetic Chains rely on a fundamental principle: efficient movement requires the integration of a stable yet dynamic foundation so that the body can generate the power needed for locomotion.

The Anterior Spiral is a culmination of everything that we’ve discussed previously. As such, let’s review how the previous four kinetic chains have worked together to get us to this final kinetic chain.

The Intrinsic system is related to the nervous system and breath. The breath is a barometer for our movement. How our breath is integrated with our movement determines how our nervous system responds. If we move in a manner by which the movement breathes the body, the sympathetic nervous system can remain down-regulated, thus giving us access to refined motor control. If instead our breath reaches the threshold of cardiovascular distress, or we are holding our breath out of bracing or fear, our sympathetic nervous system becomes up-regulated and arms the body with a flood of chemistry.

One of the markers for stress tolerance is the capacity to return from an aroused sympathetic nervous system back to a calm parasympathetic down-regulated state of being. A large percentage of our population is stuck in an up-regulated sympathetic nervous system. This is a stress reaction that results in inflammation in the body contributing to decreased healing and regenerative ability. As a result, it is becoming popular to “train” the vagus nerve — the tenth cranial nerve — to experience arming and disarming the nervous system.

There are some very good modalities to specifically address an up-regulated sympathetic nervous system. Our personal practice is one way we can take responsibility for our stress levels. Tia Chi, Qi Gung, Shamatha Meditation, and Yoga are but a few examples. I personally find getting acupuncture to be very much a sattvic practice. I go very deep into meditation as I’m observing the energy shifts in my subtle body. For people that are attracted to manual therapy, Cranial Sacral Therapy is a wonderful way to engage the nervous system and the breathing apparatus. Nervous system health very well may start with the subtle aspects of how the cranial sutures are integrating with breath and movement.

The Deep Longitudinal Kinetic Chain is about how we interact with gravity and shock absorption. Our bodies are under a constant compressive force. The energy of the compressive force changes as movement and locomotion further generates kinetic energy. The energy of our bodies in motion must be absorbed and translated. The energy is distributed across the fascial fabric of our bodies.

This energy becomes a dynamic platform, the Lateral Kinetic Chain. The Lateral KC provides dynamic stability so that the appendicular skeleton has a foundation from which to work off. Without this foundation, the body would be at a disadvantage in generating stored elastic energy.

In developmental movement, the reflexive motor learning that is hard wired into our nervous system, we see that the movements are all about creating dynamic stability with the intention of getting us upright and using a bi-ped strategy of locomotion, the walking gait.

With an established dynamic platform, we have the capacity to store and release elastic energy. Elastic energy is stored in the tissues in two modes: lengthening or stretching and coiling or compressing. When tissues lengthen or stretch, the fascia’s elasticity stores energy. This would be like stretching a rubber band across your finger and releasing it; the rubber bands soars across the room. Likewise, winding up the rubber band on a model airplane illustrates the second mechanism of storing and releasing elastic energy. As the rubber band coils tightly, energy is stored; more coiling equates to more compression that stores energy to release.

The Posterior Spiral Kinetic Chain is the avenue the body uses to coil elastic energy into the fascial springs that perpetuate the energy of the walking gait. The body is utilizing both modalities (lengthening and coiling) for activating the fascial fabric to generate stored elastic energy. As the Posterior Spiral KC is coiled to release that energy, the ipsilateral anterior spiral is lengthening. It is a coiling of one side of the body and a lengthening on the opposite. The body is utilizing both pathways simultaneously, to generate stored elastic energy.

The Anterior Spiral completes the gait cycle. Elastic energy up to this point has been stored into the tissues, and now the body is poised to do something with that energy. The body will now translate the stored elastic energy into the complementary movement. The forward motion generated by the push of the posterior spiral is realized through the leg swing of the anterior spiral.

The ability to effectively store and release elastic energy is paramount to athletic performance. In the video, notice the quality of movement this athlete displays. The timing of arm drive and leg drive, the depth of absorbing kinetic energy, and how the explosive energy increases with each shock absorption phase.  Her movement is brilliant and demonstrates healthy integrated kinetic chains at work.

The 5 Primary Kinetic Chains working together create an integrated whole. If one or more of the components are unable to engage, then we need to isolate the issue and through motor learning, reengage and integrate back into the whole. The kinetic chain charts are meant to be a map for inquiry, as we explore who is playing and who is not, the charts can help us to discern what disengaged players need to get back in the game.

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Balance

The stability or mobility question has been brought to the table many times. Which is more important ~ to be stable or to have mobility?

There are different perspectives to the answer depending on one’s field of study, the application, and the lens that you look through.

Here is my take: stability and mobility are in an interdependent relationship. One can’t effectively happen without the other.

Stability and mobility rely on each other to keep the structure safe. Stability is to software as mobility is to hardware. Stability requires motor control, the ability of the nervous system to respond appropriately as movement occurs. Mobility is the hardware, the organization of bones, joints, ligaments, tendons, muscles and fascial structures. The structure is responding to movement, messages of how movement is occurring, and how this information is being relayed up to the motor control center. A strategy is then derived as a response to the changing environment. The quality of movement being expressed is a product of integration of both stability and mobility.

Dynamic Stability is perhaps a better term to describe the product of stability and mobility. The question then shifts from “stability or mobility” to whether the body can appropriately respond to movement over a complete range of motion and a changing environment. For example, if you are hiking a steep loose trail, and the earth shifts under your feet, is the responsive mobility available for you to keep from losing footing and possibly spraining an ankle?

Dynamic Stability keeps the structure safe. The result of stability + mobility is neuromuscular integration that is available to respond appropriately to a complete range of motion. When life happens, and the environment shifts in an unforeseeable way, dynamic stability ensures an appropriate response is available.

In the movement known as the walking gait, the Lateral Kinetic Chain completes this dynamic platform. The body has just absorbed the kinetic energy through the deep longitudinal kinetic chain, the strike phase of the gait. That energy now needs to be grounded into a stable yet dynamic platform, the lateral kinetic chain, that will allow the body to generate the next movement, the power generation of the posterior spiral kinetic chain. The axis of the spine is integrating all three planes of motion while centralizing the energy from the previous shock absorption phase. As a result of dynamic stability, the body is prepared to generate propulsion, the forward motion of the walking gait.

The midline action of maintaining balance is another important action of the lateral kinetic chain. Complementary neuromuscular activations are working in cooperation to balance the relationship of movement, kinetic energy, gravity, and ground force reaction. These complementary actions provide the dynamic base so that the appendicular skeleton can generate energy.

Movement is a balancing act between environmental factors and the structure’s ability to respond appropriately. For example, when we look at the sculpture of rock stacking, we see the dance between the unique attributes of each rock. The size, shape, and center of gravity of each influences the balance point. Each rock complements the previous. The balance points create an axis, an axis of stability. Without this axis, the stack of stones would fall.

This demonstrates the third principal action of The 5 Primary Kinetic Chains ~ Axial Stability for Appendicular Mobility. When a dynamic base is in place, the appendicular skeleton can express its potential of generating stored elastic energy in movement.

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Shock Absorption

The second primary action of The 5 Primary Kinetic Chains is shock absorption. Shock absorption is the kinetic energy as it waves through the body. This concept has several contextual layers, let’s further explore shock absorption.

Kinetic energy refers to mass in motion. The earth we live on is a spinning ecosystem that comprises of many elements. Gravity is one of those elements (https://en.wikipedia.org/wiki/Gravity)

When we walk, run, or jump, our musculoskeletal system puts into motion the mass or weight of our structure. The product of the interaction between musculoskeletal activation, gravity, and ground engagement produces a wave of energy, a kinetic wave. Energy is a wave form, as it has a measurable amplitude and modulation. The amplitude is the height of the wave, or intensity, and modulation is the length of the wave, or duration.

When we are standing still, gravity is pressing our structure into the earth. In order to counter gravity, or to balance the force of gravity, we push into the earth creating a rebound. As the popular yoga saying explains, one must “root to rise, or stand tall like a mountain.” Without this action to counter gravity, we would collapse under its compressive force.

When we add momentum, our kinetic energy increases, and more energy is required to counter-act the compressive forces. Let’s explore this experientially. Take a few normal steps and notice how the impact of the strike phase of the gait is reverberating up your structure. Now increase the kinetic energy and transition from a walk to a trot. Notice how your body requires more of your structure to dissipate the energy.

Let’s increase the energy wave another notch. Try jumping up with both legs. See how much vertical height you can clear. Feel the leg drive from pushing into the earth and the absorption of kinetic energy as you reengage with the ground as you land. Now do the same thing, but drive and land with one leg only. Notice that that single leg absorption is asymmetrical. Take inventory of how this energy moves up the body, joint by joint. This is ground force reaction and is a key principal action in movement.

What happens when a joint or multiple joints are unable to participate in the distribution of kinetic energy throughout the body during the shock absorption phase of a movement? The structure must come up with a solution to dissipate the kinetic energy, this is called a compensation pattern. This is a maladaptive learned behavior that then is reinforced with each cycle of shock absorption.

Shock absorption is an essential element in structural assessment for integrated movement. The kinetic chain chart in the Deep Longitudinal anatomy poster gives great insight into how the energy of shock absorption waves through the body.