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Iliopsoas - The Flee/Fight Muscle for Survival

by Liz Koch(more info)

listed in bodywork, originally published in issue 108 - February 2005


Survival is biologically encoded in our genetic DNA. Unconditional reflexes respond before a thought crosses our minds. Triggered by internal and external sensory stimulus, these involuntary muscular responses ignite for protection.

Large and powerful, the iliopsoas muscle expresses our basic need to survive in the face of danger. Understanding the iliopsoas as part of the survival response offers both therapist and client a fresh perspective and more thoughtful approach to personal healing.

Standard Iliopsoas Protocol

Standard practice for most massage and bodywork training programmes is one of either passing over the importance of the iliopsoas or teaching a variety of manipulations with the intention of addressing the unresponsive or constricted muscle.

Located deep within the physical core, either the muscle is recognized as not easily accessible and therefore out of the range of basic massage or a major postural muscle, an integral component for realignment. For the structural practitioner, working on the iliopsoas is akin to constructing a house, important for building a good foundation. For the massage pratitioner, with the client's relaxation as top priority, a lack of awareness of the iliopsoas may result in being ill-prepared for the biological response that may appear in their client and/or themselves.

What is paramount to recognize is that both views of the iliopsoas stem from a common but limited bio-mechanical paradigm. Viewed as an object, the body is understood by examining its parts. The goal: to fix or soothe the part that is identified as a problem. Studying cadavers and anatomy books, separating origins and insertions validates the perception of the body as separate and to some degree static. Misunderstood is the phenomenon of the intrinsically motivated iliopsoas.

Trying to fit the holistic iliopsoas into the bio-mechanical paradigm is a bit like trying to push the jack back in the box and close the lid. Once we embrace all its complexity the iliopsoas simply does not fit in the box. A new container of thought is needed.

A Bio-Intelligent Paradigm

The bio-intelligent paradigm recognizes life as a self-healing continually regenerative process. The bio-intelligent iliopsoas muscle is living tissue expressing and signalling important data for perception. No longer perceived as static, its behaviour is a vital messenger. Rather than harass or even soothe the messenger in hopes of changing behaviour – listening to the dysfunctional iliopsoas points to deeper levels of integrity in disarray.

The availability of the iliopsoas, attaching along the twelfth thoracic and lumbar vertebrae reflects harmony of spinal motion or when unavailable a cacophony of spinal dissonance. Moving through the pelvis and inserting into the lesser trochanter of the femur (the medial side of the upper thigh bone) the iliopsoas is the only muscle to attach the spine to the legs. Forming a bridge between upper and lower body, the resonating iliopsoas vibrates the nuances of discord or harmony; fear or safety.[1]

The Survival Response

The iliopsoas plays a major role in the 200 million year old primitive, ritualistic, human survival response. This survival response is thought to be located in the brain stem connecting to the spinal cord. Or as Webster dictionary elucidates, the extension of the spinal cord up into the brain. Considered the oldest part of the brain, the stem is preverbal and controls the autonomic functioning of breath, heart rate and flight/flight. Called the reptilian brain, it focuses on life maintenance such as breathing, swallowing and heart pulse. It manages social behaviours affecting survival, such as hoarding, dominance, preening and mating. It also controls consciousness and determines whether one is awake or asleep.

When the survival response is activated the powerful iliopsoas muscle responds by bringing together the two ends of the spinal cord; pelvis and head. Just as when a child picks up an earthworm or caterpillar, witnessing the tubular being curling, so too our spine curls when afraid. It is the iliopsoas muscle that rolls the body into a foetal ball, protecting the portals of perception (located in the face) and vital organs from harms way. Pulling the two ends of the spinal tube together forms a resilient spine, protecting the organism from blows and falls. The ignition of the iliopsoas prepares the leg to kick high and jump quickly. Fleeing, the dynamic iliopsoas propels forward into a run. Fighting, it steels in time of combat. Playing dead, a frozen iliopsoas expresses a heightened survival response of protection or trauma.[2]

The Resolution of Trauma

Trauma is defined as any short or long term overwhelming experience that ignites the fight/flight survival response without resolution. Trauma includes prenatal and birth difficulties, physical and emotional abuse, neglect, sexual violations, surgery, dental work, accidents, natural disasters, violence, war, torture, all forms of shock, as well as living under the threat of danger. With this broad definition of trauma in mind, everyone experiences some form of trauma while living on earth.[3]

Our innate ability for resolution of trauma is as inherent a natural survival instinct as is the need for protection. Resolution is part of the survival response. Recovering personal safety is a necessity of evolution. Otherwise we cease to exist. The organism knows how to recover just as it knows how to protect. David Berceli, an international Trauma Recovery therapist, living in war zones throughout the world (specifically in Ireland, Africa and the Middle East), explains "Just as the human organism is designed to experience and endure traumatic episodes, it is also designed to recover from these experiences… recovering from trauma is genetically encoded in us to complete one process and begin something new as a part of our unending cycle of evolution".

Recognizing the iliopsoas as the primary mover of the survival response he clarifies, "Since this contraction response of the human body is autonomic, instinctual and primarily unconscious, it is not necessarily under the control or awareness of the individual. Because the human organism is genetically encoded to preserve its existence, this process of contraction is the emergency survival system designed to engage itself in any real or imagined life threatening experience. Since this emergency mode is not under the control of the conscious brain, the behaviours, actions and reactions of the individual(s) are instinctual rather than calculated and conscious. So, unlike other psychological issues, traumatic experiences cannot be immediately dealt with via conscious and logical methods to achieve a resolution. It is precisely this conscious and logical resolution of a psychological crisis versus the unconscious and illogical resolution of trauma that has tremendous implications for the therapeutic session".[4]

Berceli's work validates the need for therapists to stop manipulating the iliopsoas muscle and to support the survival response as our bio-intelligence resets its priorities. Rather than view the body as separate from its intelligence and unable to function without a jump start, our thinking mind (i.e. the neo-cortex) must reflect on and be willing to acknowledge the presence of a life force within that can guide us to safety if we are only willing to stop inhibiting its capabilities.

Author and therapist Peter Levine's book Waking the Tiger: Healing Trauma brought to light the instinctual animal nature of trauma. Recognizing that biological survival responses resolve quickly in the animal kingdom, he asked himself why not in humans? Looking at how animals naturally resolve trauma, he saw shaking as the biological response for fear. Animals shake to re-orient after a shock or trauma. Berceli, in looking for the expression of human bio-intelligence, watched young children for the cues to resolution. Young children also shake when afraid and rock to comfort. This shaking, they both discovered, quickly discharges previously released neuro-chemicals within the tissue and resolves deep muscular tension suspended for action. It switches the sympathetic (flee/fight) mode off and parasympathetic (rest/digest) mode on. Turning off the survival response frees the organism to return to fully participate in the flow of life.[5]

Diving into the Fluid Core

Emilie Conrad founder of Continuum Movement is a somatic educator specializing in spinal cord trauma. Having worked in the field of movement for over 40 years, she invokes coherency in the cerebral spinal fluid through subtle micro movements in cellular motion. Movement she affirms is not something we do; it is what we are!

A variety of sounds, she discovered, excite the wave-like motion of cerebral spinal fluid, tissue and nerves. One direct result of intentionally invoking wave motion is hydrated tissue. Via wave motion and exploring gravity her work hydrates the naturally succulent iliopsoas muscle (the filet mignon), resulting in a softening of muscular and neurological tension.

Using embryogenetics as a model for human potentiality Conrad clarifies, "When we see a newborn, essentially we are looking at the movement of water made flesh. We are seeing a fluid system meeting the vibrational field of the earth, where an elegant exchange begins to take place…The fluid presence in our bodies is our fundamental environment; we are the moving water brought to land".[6]

It is no wonder that the iliopsoas responds so positively to fluid movement; our bodies are composed of 80 per cent water. But, it is specifically the muscle's relationship to the survival response that makes fluid motion so amazingly effective.

Cerebral Spinal Fluid

The brain and spinal cord are immersed in a sea of cerebral spinal fluid (CSF). It is a pulsation of wave motion like the tide that signals the difference between life and death. The brain and spinal cord literally swim in the CSF and it has been proposed that when flowing optimally, it is the fluid that awakens our consciousness. The pulsation of CFS is dependent upon a variety of influences, including breath, heart pulse, and physical movement. Unlike our blood circulation which is moved by the heart, there is no specific pumping system for cerebral spinal fluid. Gravitational forces, the massaging effect of the iliopsoas while walking, the ebb and flow of breath, all influence the expansion and contraction of cranial sutures in the skull, pressure on the brain tissue and pelvic rocking. Breath is key, as inhalation and exhalation reflect succulent spinal movement. The fundamental rhythm of life, contraction and expansion, echoes through every aspect of our being. Sound, breath and movement re-establish coherency in the deep recesses of the spinal cord reverberating out into the iliopsoas.[7]

Core Pendulum Motion

Ignited within the belly core, walking emerges out from the core into legs and arms. Swinging the leg in pendulum motion the iliopsoas is our walking muscle.[8] Its rhythmic motion, combined with diaphragmatic breathing, massages the spinal column; elongating as we inhale and resuming balance as we exhale. Paul Chek, a prominent expert in the field of holistic health and corrective and high-performance exercise, explains "Walking results in rhythmic contraction and relaxation of muscles as well as rhythmic pressure changes in body cavities. This results in improved circulation of blood, lymph and even synovial fluid (the lubricating fluid made in joints). Steady state rhythmic walking further assists movement of body fluids. Steady state walking, or walking at a consistent effort, synchronizes breathing with movement, again causing wave-like pulsations throughout body cavities… When you're walking and breathing synchronizes directly, or in an octave relationship with other fluid pressures and pulsations, movement of all major body fluids, including cerebrospinal fluid, is assisted".[9]

What inhibits the iliopsoas during walking is a lack of safety most often due to a disruption of relationship between pelvis and cranium. Tears and stretched ligaments in the pelvis disrupt cranial sacral communication. Braces, mercury fillings, even the use of cell phones, disrupt CSF wave motion. When proprioceptive receptors responsible for organizing posture (thought to be located in the fluid joints) are disrupted, the iliopsoas muscle is required to function as a stabilizer rather than a mover. The inhibited iliopsoas is simply a reflection, not the cause of disorientation, incoherent movement.

Lifestyle Stressors

Man-made rhythms: TV, videos, movies (both vibrational and contextual), cell phones, the speed of computers, along with a barrage of stimulants in the form of coffee, chocolate, sugar and chemical additives (such as aspartame, MSG, NutraSweet) constantly signal the ancient reptilian survival response. Such stressors, combined with minimal repetitive physical movements based on mimicking machines (such as driving a car, working a computer, using exercising machines, disrupts rhythmic wave motion. The survival response is elicited by artificially stimulating the sympathetic nervous system. By evoking the sympathetic nervous system we stay in high gear. Drinking coffee, running fast- paced lives, we live in a continuous flee or fight mode.

Constantly in survival mode our adrenal glands (which sit on the kidneys and ride upon the iliopsoas muscle), the immune system and the neuropeptides essential for thriving, become exhausted. The ability to sleep deeply for regeneration, digest and assimilate completely for nourishment and make deeply pleasurable sexual connections are normal parasympathetic functioning of the autonomic nervous system. Referred to as rest and digest mode (versus flee/fight mode) it is noteworthy to recognize that when a rabbit is running from a fox it does not eat, sleep, reproduce or play. Constantly in survival response iliopsoas dysfunctions may simply reflect a pace of life that is not sustainable.

Working with the Iliopsoas

Working to re-establish iliopsoas health requires respect for its complexity and understanding its part in the survival response. Palpating the iliopsoas (no matter how sensitively approached), ignites the survival response. Rather than find resolution, invasive techniques at best bring only release. Distinguishing the difference between release and resolution is crucial for understanding the iliopsoas muscle. There is a qualitative difference between release and resolution. David Berceli in his Pathway to Healing video describes the difference: "The key to a successful recovery from trauma is to activate… the body to return to a state of rest and recuperation. Because the excessive energy created in the body during a traumatic event continually seeks an organismic discharge, it will continually repeat some form of the trauma creating a cycle of compulsive re-enactment, an endless and unstoppable neurobiological feedback loop that keeps the individual locked into a kind of psychophysical imprisonment".[10]

Triggering the iliopsoas only achieves a release through reaction. It should not be confused with resolution. The tense or unresponsive iliopsoas is expressing a process that will not be solved by bio-mechanical manipulation. Resolution is found through re-establishing safety on a very deep neuro-chemical-biological level.

Integrity and its need for clear boundaries is an important aspect of re-establishing safety. One of life's many paradoxes: what brings a sense of wholeness in the organism and a connection to life is an experience of separation and containment. When therapists attempt by direct palpation to touch the deep-seated iliopsoas muscle, they set off the survival response, experienced by the organism as intrusive and invasive. Just as poking the worm held in a child's hand provokes the worm to curl tighter. Using a logical approach in an attempt to tolerate such behaviour only maintains and further entrenches the disassociation or incoherency within the organism. At worst therapists collude in a re-enactment of the compulsive neurobiological feedback loop associated with trauma.

Re-establishing Core Integrity

There are many non-invasive ways to work with the iliopsoas that does support resolution. Rocking, gentle jiggling, falling and catching motions (Koch) all elicit safety and recovery. Sensitive non-invasive massage strokes have been developed to encourage the flow of CSF during normal massage.

Paying attention to cues coming from within especially helps evoke participation with, rather than control over, our bio-intelligence. Continuum Movement cultivates the art of sensory awareness through breath and wave motion, Brain Gym explorations mature primitive reflexes, Core Awareness,[11] Hanna Somatics and Feldenkrais (as well as Continuum Movement and Brain Gym), all teach the art of direct sensing.

Most important is for every therapist to do no harm. Being available to one's own iliopsoas muscle is absolutely essential for being prepared to support another person.


Perceiving the iliopsoas as an expression of the survival response changes our understanding of the difficult or dysfunctional iliopsoas. Unavailable, the iliopsoas is only expressing the stress generated from a lack of coherency. Rather than manipulate the iliopsoas, with the potential of driving the unconscious disruption deeper, show profound respect for the messenger requesting a need be met.

To gain understanding, experience and sensitivity for the iliopsoas requires living an open inquiry into what it truly means to be human.

References & Resources

1 Koch L. The Psoas Within. Positive Health. pp44-47. Issue 65. June 2001.
2 Koch L. The Psoas Book. Guinea Pig Publications. Felton California. USA. ISBN 0-9657944-9-7. First edition 1981. Second edition 1997.
3 Koch L. Psoas Health:Trauma Recovery Protocol. Massage & Bodywork Magazine. pp61-66. Dec/Jan 2004.
4 Berceli D. Website.
5 Levine P. Waking the Tiger: Healing Trauma. North Atlantic Books. Berkely California. USA. ISBN 1-55643-233-X. 1997.
6 Conrad E. Website www.continuummovement
7 Glassey D. MSW, DC, LMT. The Soul Swims in the CSF: The Metaphysical Physiology of the Cerebrospinal Fluid.
8 Koch L. Walking With Your Iliopsoas Muscle. Positive Health. pp48-50. Issue 74. March 2002.
9 Chek P. HHP, NMT. The Power of Walking. Printed on Website 2004.
10 Berceli D. Pathway to Healing a Trauma Recovery Program. Naka Productions. Charlotte North Carolina. USA. Video. 2002.
11 Koch L. Core Awareness: Enhancing Yoga, Pilates, Exercise & Dance. Guinea Pig Publications. Felton. California. USA. ISBN 0-9657944-8-2. 2003.


  1. Sally Holt said..

    I find Rhythic Movement Training works profoundly

  2. jenelle said..

    This author/trainer reinforces the (gentle) shaking (more like a shiver) in newborns. The shooshing seems deafening, but he supports his actions by stating it is SUPPOSED to be as loud as a vacuum cleaner.

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About Liz Koch

Liz Koch is an international somatic educator, and creator of Core Awareness ( focusing on awareness for developing human potential. With 30 years experience working with and specializing in the iliopsoas, she is recognized in the somatic, bodywork and fitness professions as an authority on the core muscle. Liz is a nationally and internationally published writer and the author of The Psoas Book, Unraveling Scoliosis CD, Core Awareness; Enhancing Yoga, Pilates, Exercise & Dance, and her new release Psoas & Back Pain CD. Approved by the USA National Certification Board for Therapeutic Massage & Bodywork (NCBTMB), as a continuing education provider, Liz Koch is a member of the International Movement Educators Assoc. (IMA).  She may be contacted via

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