The Psoas – Our Body’s Insurance Policy Against Pelvic Instability & The Case for Leaving it ALONE

Difficult to palpate, a challenging area to master as a manual therapist and dreaded by everyone getting worked on because of the horrible pain associated with it – in some ways “the psoas” is approached like the holy grail of the body: finding it can feel like a “quest” and while few are rewarded for their efforts many seem willing to die trying.

If you’ve jumped on the psoas-is-the-root-of-all-pain bandwagon, I have a few questions for you: if you’ve gone after the psoas attempting to release it – on your own, with a massage therapist, physical therapist or other method – are you better? Are you out of pain? If you’ve spent a lot of time trying to “release” this muscle, shouldn’t it be “loose” by now?

There’s been a LOT of hype about the psoas the last decade (or more). Is the hype justified? Is it really the most important muscle in the body and the biggest contributor to all of our pain?

I’ve instinctively felt for years that all this psoas hype is misplaced. I finally feel prepared to present my counter argument.

I’ve come to believe the iliopsoas are the most adaptive muscles in the human body, and our insurance policy against pelvic instability. This might make the iliopsoas two of the most important muscles in the body; however…in this scenario, if we are in pain then these muscles ARE LIKELY NOT THE PROBLEM, and if they appear “tight” they’re trying to HELP US. We’ve (unknowingly) taken out our insurance policy. Bolstering, blaming or otherwise focusing on the insurance policy that’s quickly running out because we haven’t fixed the root issue does nothing to heal the system that originally failed. If we heal the root issue our insurance policy can once again resume it’s role as critical back-up in case of system failure.

These are my theories and findings after 8 years in private practice and careful consideration of the science, anatomy, client stories and inner reasoning regarding this famous muscle group. I’m open to being wrong. I’m committed to keeping an open mind and learning alongside you, so please chime in with your thoughts.

Anatomy and function of the Iliopsoas:

Important distinctions: psoas major and iliacus are often lumped together (because they function synergistically) and are called the iliopsoas; psoas major and minor make up the psoas group; most of the hype talks about the psoas but either neglects iliacus, OR they use the word psoas when they really mean iliopsoas.

I’ll attempt to stick to these distinctions in this article.

Functions of the iliopsoas:

The iliopsoas flexes the femur at the hip joint (think of a hanging leg lift), and raises or flexes the trunk toward the hips from a supine or laying down face up position (think of a sit-up). They also laterally rotate the thigh at the hip, and psoas major laterally flexes the spine (side bending).

Psoas major also acts as a “shelf” for our organs to sit on, providing a barrier between those sensitive organs and nerves and our spine.

Iliopsoas – the most adaptive muscles in the body?

Most muscles have a primary function (action or movement). For example, your biceps flex your forearm while your triceps extend it.

Consider that all of the functions or actions of the iliopsoas can be performed by muscles that are bigger and usually stronger:

  • HIP FLEXION: The quad hip flexors in most people are overworked, almost always “on” and will attempt to perform hip flexion for the iliospoas in exercises like hanging leg lifts if given half a chance. Unless you’re extremely body aware and know how to turn your quad hip flexors “off” and let your psoas do the work, chances are you’re initiating and controlling most of this movement with your quad hip flexors, while the iliopsoas play backup.
  • TRUNK FLEXION: The quad hip flexors along with rectus abdominus will attempt to engage to help “flex” the trunk towards the hips through movements like sit-ups. You know this is happening if your lumbar spine curves (creating space between your back and the floor), your quads tighten up and your “abs” and even throat muscles like the sternocleidomastoid (SCM’s) engage to do the sit up for you. For the iliopsoas to be the major mover in this motion the legs must be kept stationary, the hips and head must remain in a neutral position and the iliopsoas becomes the main workhorse. If you’ve ever done a ton of sit-ups and your ABS got sore (rectus abdominus) but NOT your deep core muscles near your hip bones and toward your back, then you probably weren’t engaging your iliopsoas much.
  • LATERAL ROTATION OF THE FEMUR: The iliopsoas are NOT the major lateral rotators of the hip. This job belongs mostly to piriformis, gemellus superior, obturator internus, gemellus inferior, quadratus femoris and the obturator externus.
  • ADDUCTION: The iliopsoas also helps with hip adduction, but the primary hip adductors are adductor magnus, longus and brevis, with pectineus and gracilis obturator externus playing a part as well.
  • LATERAL TRUNK FLEXION: The quadtratus lumborum or QL muscles perform lateral flexion of the vertebral column, while psoas major contributes to the movement.

The primary actions of the iliopsoas are without a doubt hip and trunk flexion (in my opinion, and apparently the opinion of the internet). Yet I believe we rarely use the iliopsoas as the primary movers of these actions, relying instead on other muscles like the quad hip flexors and rectus abdominus, while the iliopsoas provide ancillary support and/or exist as our back-up muscles in case the primary movers fail to perform or become dysfunctional.

Many muscles, while responsible for a primary movement, also perform more than one action. The human body, after all, is a fully connected system that works as a whole to support movement.

Isolating ANY muscle group isn’t wise, because NO muscle functions in a vacuum and ALL muscles require the participation of the whole body. 

I propose that isolating the iliopsoas or psoas muscle(s) specifically and attempting to “treat” them in isolation is especially dangerous, because of ALL muscles in the body these are the most adaptable, the most willing to change based on our habits, posture, sports, lifestyle…and this is a very good thing! That’s their job!

It’s my position that the primary role of the iliopsoas is as an ADAPTIVE MUSCLE GROUP that, by being highly adaptable, supports the primary functions of many large and small muscles.

Because they are SO adaptable, they can step in (if the brain asks them to) to stabilize the pelvis if necessary.

I believe the iliopsoas is our body’s insurance policy against pelvic instability.

They are likely NEVER the cause of pelvic instability, and “releasing” them may destabilize our spine or pelvis making us more prone to injury, pain or instability.

If we are to help the iliopsoas do its job, then we would do best looking at the surrounding muscle groups and see who is overworking, who us under-working, who is inhibited and/or fascially restricted. Taking care of all of this IS taking care of the iliopsoas.

What if the psoas appears “tight”?

If the psoas presents as “tight” it would, in my opinion, suggest a pelvic instability issue and/or low back pain pattern, and it is attempting to create stability, or in other words…we’ve cashed in on our insurance policy.

I’ve used quotations around “tight” because I believe this is one of several situations when the brain steps in and creates a neuroligcal tightening of a muscle to protect us from injury and spinal damage. The muscle is NOT in actuality tight or shortened, and if the pelvic instability or low back pain pattern is resolved, I believe it would relax into its normal healthy state.

If the psoas muscle itself is actually literally in a “shortened” state (rare in my opinion) it could contribute to “flat back” posture, or a posterior pelvic tilt.

Most people in modern society have the opposite: an anterior pelvic tilt (lordosis, or sway back), which would actually put the psoas into an overstretched position.

I’ve seen the iliopsoas blamed for both “sway back” and “flat back” postures, and I’ve seen both blamed on tight and weak psoas muscles. I don’t think it’s productive to examine these in detail because we’d be here all day since there are so many possible patterns for both of these scenarios.

As you can see…there is a lot of overlap and confusion as to what causes what regarding the iliopsoas, and I believe it’s because the iliopsoas doesn’t have a primary function and is so adaptable.

The psoas muscles and fascia can appear “tight” due to FASCIAL RESTRICTIONS around them.

The psoas and iliacus are not in fact “tight” much of the time (at least not in my office), though they may appear so on occasion. More accurately, I don’t believe there are a lot of fascial restriction within the muscles themselves.

A “tight” muscle does NOT necessarily equal a strong muscle; a strong muscle does NOT automatically mean that muscle is “tight.”

Healthy muscles will be strong AND flexible.

I believe in most people the iliacus and psoas are weak.

If you have fascial restrictions within your abdominal cavity, fascial restrictions in your quad hip flexors, fascial restrictions in one or more of your high adductors, a “tight” quadratus lumborum muscle (due to a low back pain pattern, whether pain is present or not), or a restricted diaphragm (do you hold your breath a lot?) then chances are your psoas will appear tight due to being pulled on, especially if pulled in more than one direction at a time.

The case for leaving the iliopsoas ALONE:

Releasing the iliopsoas may temporarily bring relief to an issue but this rarely (in my experience) resolves it for good (because it’s NOT the root of most problems), and it could make the pain worse. For example, if the iliopsoas has tightened up (neurologically) to protect the pelvis and/or spine from instability and it’s released, then we’ve created a scenario in which injury and damage is now much more likely.

There’s a TON of fascia in our abdomens surrounding the psoas muscles – it wraps all of the muscles in our abdomens as well as every nerve ending, organ and bone (pelvis, ribs and spine).

If you attempt to go after psoas major specifically, I believe there is very real danger in irritating your organs, nerves, arteries/veins etc, so I NEVER recommend trying to dig into your belly to get at the psoas. You’d be far better off addressing your abdominal fascia specifically.

This abdominal fascia can get tight, knotted up and twisted due to processing stress or anxiety in the gut, sucking in the belly all day in order to have a socially acceptable “flat” tummy, digestive issues etc.

The MAIN area of the body that is likely pulling on the psoas causing it to appear “tight” is the quad hip flexor fascia.

I’m not sure why so many articles have been written on the psoas being the main muscle to suffer due to us sitting all day, when it seems obvious to me that it is our quad hip flexors (and specifically the fascia in this area) that take the brunt of all this sitting and become restricted, knotted up and “tight.”

Not only are we overworking our quads (specifically the quad hip flexors) by sitting all day, but we’re also an intensely quad dominant society. Almost all of our sports are quad dominant – soccer, football, gymnastics, cycling, running (this one shouldn’t be, but it often is, especially in trail running because many of us haven’t learned to use our hamstrings and glutes), swimming, Olympic lifting and certainly the biggest modern culprit: CrossFit (and Olympic lifting).

Take action! Your best bets for helping your iliopsoas chill out:

  • Click here to learn how to release the fascia within your quads and quad hip flexors. This is my TOP PICK and #1 recommendation if you’re convinced your psoas is “tight” or causing pain.
  • Click here to learn how to release the fascia within your adductors.
  • Click here to learn how to release your abdominal fascia.
  • Learn how to RELAX your diaphragm and belly and BREATHE! So many people hold their breath all day (I used to be one of them) and this can stress your psoas.
  • And last…I believe most of us would benefit not from “releasing” these muscles but from STRENGTHENING THEM. Stay tuned for future episodes of Mobility Mastery Monday where I’ll cover this topic. In the meantime, if you’re attempting to strengthen these muscles, make sure you’re doing it correctly and not engaging the OTHER primary movers I talked about in this article. Make sure your quads and rectus abdominus aren’t doing ALL the work.

How to get the most out of the iliopsoas technique:

  • Use a medium weight kettlebell such as 15, 18 or 20lbs.
  • Use caution if you attempt to use a super heavy kettlebell – you have a LOT of sensitive nerves and tissue in your abdomen and less is more where this technique is concerned.
  • Don’t use LESS than 15lbs…or this won’t be very effective. Stay in the MEDIUM WEIGHT range.
  • Place the handle at an angle right next to your iliac crest or “hip bone.”
  • If you don’t feel anything (no tenderness, soreness etc), try moving your leg and if you get your knee close to the ground you can be sure your iliopsoas is NOT tight.
  • If you feel a LOT of tenderness or soreness with the kettlebell handle in this area, you may have some fascial restriction here. Your psoas fascia might be stuck to your iliacus fascia, which in turn might be adhesed (too much) to your hip. IF YOU DO, PLEASE TRY THE QUAD HIP FLEXOR TECHNIQUE FIRST. I want this technique to mostly be a test/retest for those of you who want to experiment with whether or not your psoas needs releasing at all.
  • If this area IS sore and you go after it first without trying the quad hip flexor technique (or any of the other ones), PLEASE BE AWARE THAT WHATEVER PAIN YOU HAVE MIGHT GET WORSE. If it does, this definitely suggests that your body had cashed in on its insurance policy and you just loosened up the only muscle keeping your pelvis stable. If this happens, your best bet would actually be to try and tighten it back up by targeting your iliopsoas for strengthening. And then go after your quad and hip flexor fascia, or anything else your instincts tell you could be part of the problem.
  • Spend no more than 30-45 seconds in this area! That is MORE than enough time to accomplish the task without running the risk of overworking the area.
  • If something feels wrong, STOP. There are a ton of nerves and your large and small intestines are close by.

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  • Chris says:

    One of my hips do not rotate out, same side that I sustained a subluxation of the SI joint during a chilldbirthing injury. I felt like this occurred (10+) years later to protect the unstable si joint. Doc sent me to therapy where they worked to “release” the “tight” psoas. The hip snapping thathad prompted me to go to the doc was easily solved, however as soon as they atarted me on strengthening exercises I develooed pain going down the same leg. I questioned this but was told that it was the right thing to be doing. I quit and the pain eventuall stopped after a couple months.
    Last year I had some pain in my arm, doc sent me to therapy and again they “released” the tight muscles. Now I have more pain from the movement in the joints that my muscles were tight trying to protect me. Pain is all the time. I believe you are so right about our brain doong things to protect us from further damage and pain.
    My new therapist understands and is not targeting isolated muscles but working groups and general movements. Great article! Thank you!

  • RMS says:

    By doing a simple google search of “shortened psoas muscle” I am seeing everywhere that a shortened psoas muscle actually contributes to ANTERIOR pelvic tilt, while you mention here that a shortened psoas muscle contributes to posterior pelvic tilt. Which is it?

    • I may have an unconventional view of this issue, but in the case of psoas I believe it’s worth looking at the fact the muscle attaches anteriorly and posteriorly. It’s my opinion that a “shortened” psoas is more like a coil of rope snug in its resting place, rather than overnight from overuse. Using the psoas, or overusing it in a way that creates fascial shortening, would require that we lengthen and shorten it, aka contract those tissues on a regular basis. But sitting doesn’t overuse the psoas, we rely far more on the quad hip flexors for this (most people, not all). My personal take on the body is never to assume anything and let the body speak, and I’ve rarely found it necessary to “release” the psoas in anyone for any reason, but the most common reason I get asked to check it is the case of low back pain. In a decade of private practice I’ve never seen it be the cause for low back pain. Thanks for the question, good luck on the search!

      • Vi says:

        I started doing a stretch I was told stretches the psoas. 1. Left knee on ground, left hand holds left foot flexed toward glute. 2. Right foot in front, knee over ankle, hand on femur at knee, body erect. It helps my low back so much, (Hope that makes sense). I’m in love w/ that stretch.. IS that stretching the psoas? Also those ancillary muscles? This article is so informative, thanks!!

        • Hi Vi, yes that will stretch your psoas a little, but mostly it’s stretching your QUAD hip flexors. Stretching like that (it’s called static stretching) can help manage pain, but it won’t eliminate it for good. I recommend using my free techniques for low back pain (you can search for it on the site).

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