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”?