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Pilates on Call: Liz Koch Discusses the Psoas

It’s time again for another Pilates on Call, our open Q&A with Pilates and movement experts. Liz Koch, an expert on the psoas, has kindly volunteered to answer any and all of your questions about this deep, important muscle. For a general background on the posas, you can read her article Intro to the Psoas.

If you have questions about how the psoas relates to Pilates, now is your chance to get answers. You can leave your questions for Liz in the comments section below or email editor@pilates-pro.com. Liz will get to them as quickly as possible, but might need a day or two to respond.

Liz Koch is an international somatic educator and creator of Core Awareness™ focusing on awareness for exploring human potential. With over 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 the author of The Psoas Book, Unraveling Scoliosis, Core Awareness: Enhancing Yoga, Pilates, Exercise & Dance, and The Psoas and Back Pain. 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 Association (IMA). Learn more at coreawareness.com.

Posted on Wednesday, October 20, 2010 at 03:35PM by Registered CommenterPilates-Pro in , , , , | Comments32 Comments

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Reader Comments (32)

Hi Liz. I am a pilates instructor and often I encounter clients with a problematic psoas on one side. This psoas often does not respond to stretching and seems slow to fire and funnily enough seems to almost always be on the left side, is this organ related? What is the best way to strengthen the weaker psoas, I have many stretches in my repertoire but find it hard to find ways to strengthen with success, single leg knee lift exercises with foam roll under spine sometimes helps. Would love to hear any suggestions. Many thanks.

October 21, 2010 | Unregistered CommenterTara

yes....what's with the left side? I personally have the same issue when I am very tired or run more than usual. My bag of tricks (stretches)don't always work.

Great article!

October 21, 2010 | Unregistered CommenterDevra Swiger

Hi Tara, Thanks for your question.The psoas is not like any other muscle tissue. It is more like the tongue than an external muscle; it is an organ of perception. People do not have a "weak" psoas they have an exhausted psoas. So before you can stretch this tissue the real problems need addressing. Once a person stops misusing, overusing and absuing their psoas it can regain its juicy nature and then the tissue can be stretched. What I recommend is shifting the idea that we need to fix the psoas to one of listening to its message. Most"psoas problems" reflect a sacral iliac joint dysfunction. So I recommend regaining pelvic coherency by eliminating muscle dominance, learning good ergonomics, and gaining articulated hip sockets.

October 21, 2010 | Unregistered CommenterLiz Koch

Hi Devra, Thank you for your comment, question, and feedback. I don't find people have issues on one side more than the other. Having said that the signoid colon is on the left lower side right near the psoas!

October 21, 2010 | Unregistered CommenterLiz Koch

Hi Liz, thank you for a very interesting artical! I have recently completed a course in Muscle Activation Therapy which rings tru with your mention of breathing and relaxing to regain a parasympathetic nerwous system. On the course however, we are taught to palpate, with thumbs in a circular motion the area 3cm on either side of the naval to "release" the Psoas. You mention in the artical that this is not recommended? Could you shed some light on this please. Thanks again!

October 22, 2010 | Unregistered CommenterAna

I would like to suggest and remind ourselves that ALL muscle tissue in the body has proprioceptive/sensory roles. In fact the only way any muscle can function properly is through adequate sensory input. Otherwise, motor coordination wouldn't be possible. As a whole, muscles are rather stupid in their inherent intelligence... it is the cns doing the work for the most part, except for spinal reflexes.

So I wouldn't call the psoas "unlike any other muscle" or a "sensory organ" any moreso than other muscles per say. In fact, the suboccipital muscles have more sensory receptors per volume than the psoas by far.... the neck is much richer/denser in sensory neurons than the psoas and iliacus combined.

And more accurately stated would be that SIJ dysfunction is dependent on the relationship of the.pelvic innominates with the sacrum (SI Joints), which is governed by the tensional balance of the soft tissues surronding and infkuencing these regions. Joints in and of themselves rarely are the "cause" of the dysfunction or muscle problems, unless its degenerative or pathologic. Most often it is the dysfunctional coordination of the muscles/soft tissues, for whatever reason it might be, that ends up disrupting mechanics at the joint levels causing pain/dysfunction.

I've dissected, and the psoas is the same tissue quality as any other muscle. And it does not "dry" out... That would be tough to demonstrate...?

October 22, 2010 | Unregistered CommenterMark


That is not a safe place to palpate the psoas, let alone work on it. Besides, 'rubbing' the psoas in circles isn't going to do much but irritate it and the ureters coming down on top of it from the kidneys. This is why she says dont't do it...because most don't know bow safely.

October 22, 2010 | Unregistered CommenterMark

Hi Ana & Mark, thank you for both writing in. I just spent the evening with Tom Myers author of Anatomy Trains and Melt Method creator Sue Hitzmann discussing neurology, fascial continuums, and new ways of understanding living systems over a delicious japanese dinner. The idea that nerves exisit in only certain locations is an old theroy, which both challenge.My question to these innovative teachers is where do they understand proprioceptive awareness to be found? I for one think it is in the fluid dynamic. I am speaking about the signals that inform us about gravity (not relationship to objects),and ground force reaction: in other words our internal compass that informs us of where we are in space and time.
Personally I am interested in looking beyond the bio-mechanical story to a much wider field of understanding. Even in disection it is recognized that the human system as a whole is seperated with the flick of our scaple. And observing living systems, I must add, is very different from looking at dead tissue.

Mark is right about palpation and why it is unsafe. However I also believe that it is time to let go of the "fix it" model that sees the body as object and a stupid one at that. I am interested in human potential as bio-dynamic and bio-intelligent.

October 22, 2010 | Unregistered CommenterLiz Koch

Thank u for your reply Mark. If u don't mind my asking, what is your qualification? I am extremely concerned as to why we have been taught something that is clearly wrong. There are a whole lot of practitioners out there "palpating the psoas" of unsuspecting clients. I have had a look at Liz's material on Psoas release, what is your take on using the CRP and also the active support of the legs? Can u recommend any further reliable reading?

October 22, 2010 | Unregistered CommenterAna

Hi Liz,thank u too for your reply. I am hoping to attend Tom Myers' course in Cape Town in Feb next year so it's great to hear there is on-going discussion about this amazing body we all posses!It's so much more than just science.May I ask if you could direct me to some good reading to assist with my anatomy studies?Thank You

October 23, 2010 | Unregistered CommenterAna

Thank you for the above information. My concern is the activation of the psoas in abdominal work. It is quite challenging to activate the TA when the psoas tries to overpower the stability in the pelvis. I also find it challenging to sit on top of the IT bones when once again the psoas tries to overpower, along with the back issues it all creates. Do you have some suggestions on how to release activation of the psoas and fire the other muscles needed in these positions. Also, for long distance runners, is it a sign of weaker imbalanced hamstrings and glutes that brings about psoas issues?

October 23, 2010 | Unregistered CommenterKimberley

Yes, I'm familar with the notions your suggesting, worthy inquiries I agree. As a former student of Tom's, we in the manual community also share these thoughts, some at least. I was referring to the proprioceptors in the tissues throughout the, not just the psoas, that relate us to gravity. Relationship to objects is relevant, but a slighlty differnt form of proprioception/mechanoreception/vestibulochoclear perception.

Although the cadaver form is not living tissue it does give an accurate portrayal of relationships and interactions. And we now know that the fascial tissues throughout the whole body are embedded with type III and IV mechanoreceptors that respond to various sensory input/stimulus, gravity included.

I also don't believe in the 'fix-it' model, and I don't believe that is the intention of everyone who is doing manual somatic work. It is a misunderstanding to suggest that just because someone is offering direct, sensitive and painless awareness of the psoas or iliacus via manual contact, they are trying to "fix" something. There are safe and effective ways to work manually, the goal is not always to 'release' a mechanical restriction... As I personally believe, muscles are stupid. Forcing their release is even dumber. Creating a different sensory input is key, as sensory input and perception governs muscular motor output.

Unfortunately, many people are taught many things that aren't very safe. It's difficult to control who teaches/does what. Let your knowledge of anatomy be your ultimate guide and you should feel good and safe about what you're doing. If you know where your hands are and what you're touching, you'll know how to work accordingly, and when not to do something. Physiology is also very important, even if we still know very little in the grand scheme, we'll at least know when something presented to us is based on some likely possibility, or when it is off the wall incorrect.

Take some classes/trainings with Tom. He knows his stuff very well, and is also very open to what may be beyond. He'll offer you the substance to back up what you're doing, rather than just metaphors that sound good.

Look to the iliacus more/as well for positioning of the pelvic innominates, as it attaches directly to the pelvis in a substantial way, so as to have a much greater influence on its movement. Also, look into the lateral rotators of the hip (obturators, piriformis, etc.) for balancing/counterbalancing the psoas. Hamstrings,glutes, magnus as well, but more directly the rotators and QLs.

October 23, 2010 | Unregistered CommenterMark

Hi Mark,It seems to me that you might like to write your own article for Pro-pilates. I recommend your doing so. As I was asked to respond to the Q & A for the next two weeks, I respectuflly request that when the question is directed to me not just an open comment, that you do not step in until I respond. To much to ask?

October 23, 2010 | Unregistered CommenterLiz Koch

Hi Kimberly, When exploring abdominals I recommend working with the idea of layering movement. The energetic expression of the abdominals moves up and together, whereas the psoas flows down into the pelvis, genitals, legs and feet. If the psoas is activated it may be because there is a lack of coherency in the skeletal core, which demands the psoas be used to compensate. Or it may be a lack of differentiation between the layers of movement. I recommend that you go to my web site and read the article "The Psoas Is Not Hip Flexor". What I feel is most important is to realize that the psoas is not the problem it is the messanger so don't shoot the messanger - or to say it another way as soon as the their is safety the psoas lets down.

October 23, 2010 | Unregistered CommenterLiz Koch

Hi Ana, My recommendation for innovative understanding of human potential is to study the work of Emilie Conrad (Continue Movement) and the research of Dr Valerie Hunt PhD. Most anatomy is bio-mechanical but if you want anatomy than Gil Hedley is who I would go check out.

October 23, 2010 | Unregistered CommenterLiz Koch

Getting clients to feel and use the psoas over the rectus femoris can be very tricky.

I would love to have more tools in my belt than just the classic leg slide, knee fold and tabletop leg isometric press.

If these exercises are the most effective in your estimation, of course I will continue to use them. However, I have learned that I have to create awareness with repeated attempts and multiple different approaches, so variety is helpful.

Thank you for sharing your expertise --

October 24, 2010 | Unregistered CommenterJennifer Hanning

Fair enough...

In closing, "most anatomy" is classical anatomy, origin/insertion/concentric actions. Fascial anatomy is both biomechanical and tenegrity of the whole. The next step in understanding functional movement and the reality of global interconnectedness. Individual muscles were formed with scalpels. As they exist in the body they are completely interdependent and continuous.

Your article on psoas and hip flexion, ??? The psoas does in fact shorten/contrentrically contract during hip flexion. 'Flexion is not the "closing" of a joint. When the hip moves into flexion the ball and socket of the hip merely glide/rotate, the same as it does in extension, adduction and abduction. No "closing". And the hamstrings are knee flexors, which reside on the back of the body, not front.

If the psoas was not a muscle, as you suggest, then why did the body evolve to have so many muscle 'fibers' in the psoas? As we know, the sole purpose and function of a muscle fiber is to contract, ecentric or concentric, when its 'motor' neuron sends an action potential/impulse. That's it! Thats all a muscle fiber does. The sensory (proprioceptors included) neurons are not the same neurons as motor neurons, this we know. So why have such a large muscle if it was meant to be purely sensory? Other tissues in the body such as ligaments and capsular tissues play a HUGE sensory role, as their sensory innervation demonstrates, yet they do not contract with any significance as to move two approximating bones. Why wouldn't the psoas be designed more like that? Fewer, or no, muscle fibers? And why does the psoas contracting and 'pop up' under my fingers when someone is laying on their back, knees bent, feet grounded and they initiate lifting their knee? That is actice hip flexion. Seems curious to me how the psoas 'shouldn't/couldn't' be involved in this, along with ilacus (a seperate muscle in both function and form by the way... 'iliopsoas' is not a single muscle, but two that share a relationship and subsequent attachment as they cross over the pubic ramus, not hip socket. From that 'fulcrum' point as the common tendon passes back to the lesser trocanter it allows the two muscles to retain their individual function, sensory and motor alike as with all muscles. Their function is very different above that point though.). Lateral and medial rotation only elicit minor response from the psoas in terms of motor function and pelvic tilt both posterior and anterior elicit response, and lumbar flexion and extension elicit response/motor signaling of different fibers depending. So we know that all muscles have sensory spindles and organs, and that their fascia contain other proprioceptive neurons, so why is the largish psoas embedded with muscle fibers yet doesn't perform muscular actions/create movement with the rest?

Although I see where you're going with your biodynamic approach (very cliche these days), the biomechanical (analysis or observation of human movement) model is still relevant as long as we are physicalv beings. I think you've sterotyped biomechanical to suggest 'levers' and such and are failing to acknowledge that many of us see it in a very connected and relational way, not unlike how you may see it, but describe it with different language.

That's all, = have to stop somewhere... By the way, the psoas is NOT the only muscle that connects the spine to the legs... Piriformis does that as well, from the anterior sacrum to the greater trocanter. Sometimes that slips by when we're so focused on one thing and forget to see it in its larger and actual context. The psoas is not alone, nor does it 'sense' or 'act' on its own by any means.

I will retire my commentary for the remainder of your time here. Thanks for being open to other perspectives.:-)

October 24, 2010 | Unregistered CommenterMark

Hi Jennifer, I simply don't"use" the Psoas. I have found over 30 years of exploring the psoas that its behavior offers a neutrality within the core. Perceptual and responsive but basically less is more. Maybe an image that you might find helpful is how a baby moves. A fluid being expresses it self in dynamic ways that are not muscle specific. That is how I experience the psoas. It is a subtle difference but makes a huge difference in the quality of sensation. Hope that helps.

October 25, 2010 | Unregistered CommenterLiz Koch

Hi Mark,
Thank you for your long and detailed educational comments. If you are actually interested in my perspective I will share the following. I agree that bio-mechanics is a dynamic field that is rapidly developing in very exciting directions. I have no issue with anatomy or bio-mechanics and as you clearly point out, the science of body, is not where my expertise rests.

BUT lets be very clear - The map is not the terrain.

I understand that people are excited by the map and that it can shift our ideas around what it is to be a body. However, what I have seen in the past 30 years of teaching is that professional understanding, no matter how many credentials or developed expertise one may hold, is not the same as a deep perceptual experience of self. What I have perceived working with a diverse population of people with broad movement interests, is a common vulnerability. A fragile capacity to be moved by their own sensation.

I believe culturally prevalent is a dominance model that focuses on a need to control rather than become awareness. A top down model in which we tend to want to fix rather than embody. One might say a deep primal fear. A taboo of being an animal.

If we explore living tissue as bio-intelligent, and recognize that we are a part of a cosmic/planetary consciousness, which we really do not understand then the psoas is a very interesting entry point of inquiry. The psoas (and metaphors are inherent in our thinking) an organ of perception and like the tongue simply does not need to be controlled or exercised.

October 25, 2010 | Unregistered CommenterLiz Koch

Hi Liz,

I explored my own psoas last September in Denmark at the Sukkerfabrikken with you and Lene's group. It is amazing what a little patience and understanding with this muscle can result in. Stress and anxiety melt way, the positive changes in all participants were significant.
In my humble opinion,spine surgeons must learn about the psoas: non-invasive treatment instead of operations. Health care costs will drop dramatically!

I've worked with my own clients using your explorations of the psoas, it was like magic. One client's pelvic pain disappeared after 8 years. She could work again without pain. This happened in a 1 hour session!

Do you have any recommendations on restless legs?
And any tips on an over eager rectus femoris?


October 25, 2010 | Unregistered Commentermina

Here's a question that came in via email:

Q: I have a client who is an avid golfer...he plays about 5-6 days a week. We have been working together for about two years to help improve his golf. He has never experienced back pain until recently. He went to see his chiropractor and was told that he had a very weak psoas and that if he didn't strengthen it he would never have a stable base in his golf swing.

This puzzles me, I never thought of the psoas as a stabilizer. Is it? And if so, how does it stabilize the pelvis and how do you strengthen it.

Thank you for your assistance and knowledge.

Liz Koch responds:

A: Denise I agree with you. The psoas is not a stabilizer unless misused. The problem golf presents is one of torquing. If your client does not move by rotating around his articulated femur joint, than he will torque his knees and lower spine. If his psoas is "weak" then it is actually exhausted. As a messenger of the midline and the survival response the psoas maintains midline coherency. From my point of view a golfer needs proprioceptive awareness regarding where he initiates his power (swing), he needs be engaged in activities that counter balance the repetitive one-sided activity of golf (unravel to neutral), which pilates offers, and he needs a supple dynamic psoas (not a stabilizer).


October 25, 2010 | Registered CommenterPilates-Pro

Hi Mina,
As a Pilate trainer I invite you to share some of the ways you are now including core awareness of the psoas in your work.
As for those over active quads! I recommend learning to stay aware and initiate movement from a sense of softening in ones core rather than initiating the movement in the quad. Quads (front of the leg) in energetic oriental medicine are associated with stomach meridian. Bob Cooley author of the Genius of Flexibility associates them with trust or lack there of. When we feel we have to try hard we activate the quad. Strengthening the hamstrings, self-massage on an exercise roller, balanced stretching, bone tapping, and most of all developing core awareness all assist in softening the gripping action of the quads. A person has to feel that there is something else to trust deeper within and that trust I believe comes from sensing the bones. I also write about over-development of muscle groups in my book Core Awareness.

October 26, 2010 | Unregistered CommenterLiz Koch

Here are some questions from Sandy that came in via email:

Q How can I best advise students in a Pilates mat class when doing a C curve to assist them to avoid hip flexor over recruitment? Initially I have them plant their feet on the floor securely. Then, I encourage them to draw in and wide deeply through their transverse abdominal muscles, but sometimes, some students need to stop because hip flexors bother them. Are there any words of wisdom for them?

Hi Sandy,
I am not sure if you are speaking about a standing or sitting C curve. From the point of the Psoas, behind those abdominals and deep in the core it is best to soften and feel the expression of the spine. The C curve is a primal movement called the primitive C. It is the expression of protection, fear response and propelled motion (the falling response). If you fall out of a tree or high place your body will instinctively roll. This instinctive response also happens when we jump out of a plane, or are propelled through space. My point is that working with the C curve is connected to the fear response. Some people are moving into the startle response which activates the quads. If that is the case it might be wise to neutralize the core. Some of the ways one can do this is by simply softening tension around the hip sockets, first exploring falling and rolling before working in a static position, rocking the pelvis on top and over an exercise roller to elicit and complete the instinctive response called startle and fetal.

Q What is the best way to stretch the hip flexors in your opinion?

A The hip flexors are above the Psoas so I think it helps to become more skeletally aware. The more aligned the less compensation happens.


October 27, 2010 | Registered CommenterPilates-Pro


I've read a lot of your work...and I still don't understand what you mean when you differentiate between a "weak" psoas and an "exhausted" psoas. Isn't "weak" and "exhausted" synonymous? Or are you saying that the psoas can be exhausted because it is just compensating for other muscles and shouldn't' be working so hard but it might be weak?
I am hypermobile in many areas including my hips and I often have trouble with my right psoas...and I know it's weak because if I lie on my back I can lift my left leg off the floor but not my right leg. Or in pilates class on the reformer, I can pull my left leg in (flexion) from behind using springs easier than my right leg. So there is clearly a weakness on the right side somehow. I work on "strengthening at length," which I understand is better, but I'm trying to get more of an understanding of what you mean by weak vs. exhausted.

October 27, 2010 | Unregistered CommenterSharon Goldman

Is extreme pain of the groin area - that is even in a sitting position connected to the psoas dysfunction? I thought it was interesting that I read your article within a week of having a new client with such a condition. She says stretching doesn't seem to be helping (those given to her by her Dr.) -- when she sits tailor sit - her right side for extremely high up (like a chicken wing). I feel I am a novice trainer compared to all the others here...so lots of input please! (She says she was told she has arthritis...and thinking of doing a CTScan on the area...she literally drags her foot on her bad side when she walks....) thanks for your article, Liz.

October 27, 2010 | Unregistered Commenterjoy2bwell
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