It's more than a hip flexor. Here's a look at my all-time favorite muscle, and why you should be taking really good care of yours.
The psoas is my favorite muscle of all-time. Not because I play favorites, but because it's just so important for the health of your spine and posture, for preventing the need for risky surgeries, injections, or medications, and because I've felt it, worked with it, and restored it in so many people's bodies over the years.
I respect it, and I understand it really well.
The psoas muscle is fundamental to the health of your body. The muscle group has been gaining awareness in health and fitness circles recently, but most people have no clue that it exists, or they’ve heard of it as something to stretch maybe, but they don’t understand the true significance.
This is one of those areas of the body that can affect many other areas. So when we focus here, we can stave off many common injuries, like low back pain, plantar fasciitis, knee pains of all kinds, achilles tendinopathy, sciatica, and even shoulder and neck problems. It all relates to posture.
There once was a time when I, as a Physical Therapist, was focusing on where the pain was with all my patients. If they had low back pain, I, as a well-trained and diligent product of my schooling, would heat patient’s back muscles, then massage those muscles, perform joint mobilizations to the spine, show them core strengthening exercises, ice and e-stim the back. They maybe got better, but somehow I felt like we were missing something important. Once I realized that we’d learned to overlook the front stabilizers completely, a huge piece of the puzzle, and how to actually focus there, the results I got for my patients were night and day. They still had to do some daily work, but they now had function on their side.
The same was true with other chronic ailments like foot or knee pain, hip or sciatica problems, and neck or shoulder issues. Once I helped them attain more room to re-pattern their posture, their symptoms improved more swiftly and for the long-term. And a lot of it had to do with the psoas.
I’ve literally felt this muscle in hundreds of people’s bodies over the years, and I know it well. I know how it responds, what helps it most (hint: it’s not strengthening), and just how much impact it has on either the health or dysfunction of anyone’s mechanical health and alignment.
In this article, I’ll list the 23 most important things I’d want anyone to know about the psoas muscle.
Let’s dive in.
The psoas has a silent “p.”
It’s a funny word, I know. But just drop the “p” and it’s simply pronounced SO-AS.
The psoas has a sidekick: the iliacus.
The iliacus muscle (pronounced ILLY-ACK-IS) has a common attachment with the psoas on the upper part of the leg. It is also important, and has a slightly different role because of its attachments.
The psoas is not on the back of the body nor does it wrap around.
It simply attaches from the spine to the leg along the front of the body. Other muscles wrap from back to front like the transversus abdominus or the internal and external obliques. These are more superficial and do not attach to the spine like the psoas. The psoas goes from just below your ribcage to the upper leg on each side, left and right. It’s like a tenderloin that’s on either side of an imaginary zipper line along the center of your torso.
The psoas is not a hip flexor.
That may sound like a bold statement, but it’s one I get passionate about because most people and practitioners seem to think of the psoas as a hip flexor. Which means they massage over the front of the hip, or try to stretch in a particular way, and miss all of the other attachments that make it unique in the body.
The psoas is a lumbar stabilizer (and a hip flexor).
The psoas muscle is attached along the front side of the spine at the level of each vertebrae and its disc. It crosses the hip joint without attaching to it, and then attaches on the upper part of the thigh (femur) at a bony protuberance called the lesser trochanter of the femur.
It’s the only muscle group that attaches the spine to the leg on each side.
Because the psoas has attachments along the front vertebrae to the front upper leg on each side, it’s essentially connecting the lower body (the legs) to the trunk (via the spine). Nothing on your backside crosses the hip joint like this. Nothing on the back attaches the spine to the legs.
It’s deeper than the usual “core” that we think about.
When people talk about core strengthening, they usually mean the superficial muscles of the core: the rectus abdominis (the 6-pack abs), the transversus abdominus, the obliques, and even the glutes, quads, and hamstrings and other pillar muscle groups. These are all really important, supportive muscles, especially when lifting or carrying heavy loads. The psoas is beneath, or behind, or “deep to” these core muscles and attached to the spine. Because of this, I like to call it the “core of the core.” It’s an often ignored area because most people just don’t go deep enough.
The psoas rarely needs strengthening.
The main problem I see every day in the clinic is not a strength problem (in other words, a weakness problem that needs strengthening), but a tightness problem. The psoas tends to get patterned into tension, restriction, or shortness. This makes sense because of our daily lifestyles. Because it crosses the hip joint, every time we bend or move forward, we shorten it. This includes bending forward, walking or running which lifts the leg, or any kind of sitting. With sitting, the psoas is shortened because the hip is flexed.
Any time the hip is flexed, the psoas is shortened.
Hip flexion means that the angle where your leg meets your torso is less than 180 degrees. Imagine sitting. In this position your hip joint is at a 90 degree angle, plus or minus some degrees depending on the height of the chair, or your height. You can sit on a posture chair, which is less of an angle, but still a flexed angle. Any kind of sitting creates hip flexion. Only when you’re standing or leaning backward are you neutral or extending in the hip. Or extending your leg backward is hip extension too. The psoas is a combination of lumbar and hip motions, so they are both important here. We don’t need a ton of hip or lumbar extension, usually just enough to balance out all the flexion we do in any given day.
Any time you lift your leg, the psoas is shortened.
Walking, running, some strokes in swimming, pool running, marches, or other drills. These all create repetitive contraction in the psoas. This is fine, when the psoas is healthy and fully functioning. If it’s become patterned, stiff, or dysfunctional, then these motions can feed into the problem and create irritation or overworking. This usually appears not in the psoas itself, but in the low back, hip, knees, or feet.
Any dysfunction or tightness in the psoas can create risky footstrike pattern over time, that sets you up for bigger problems.
Because the psoas attaches to each leg, when it’s shortened it pulls the leg upward and rolls it inward. This creates compensatory motions down the leg, such as landing on the outer foot, and increased pressure in the knee. This excess pressure accumulates over time, resulting in problems like plantar fasciitis, achilles tendinopathy, knee pain, runner’s knee, hip pain, hip labral tears, piriformis syndrome, glute weakness, etc.
Any dysfunction or tightness in the psoas can create risky postural patterns over time, that can lead to disc herniations, ruptures, bulges, sciatica, or stenosis.
Because the psoas is attached to the vertebrae and discs on the front of the spine, when it gets patterned into a shortened state it creates compression in the spine. It takes out the natural curvatures of the spine, compresses or squeezes the discs, and adds up to big problems if left unaddressed. When someone comes to see me with low back pain, disc herniations, sciatica, or stenosis, I always find they have psoas tension. When we release it, it can resolve the problem in the long-term.
The longer your psoas has been tight, the longer it may take to resolve the tension.
Someone who’s been struggling with low back pain or problems for a long time, has likely had psoas tension that has been overlooked for a long time, probably years, even decades. It takes that long for these postural patterns to accumulate, unless a fall or accident sets it off at younger ages. The great news is, it can still change. You don’t have to “just get used to it.”
The body is great at healing and adapting if we know what to do to help it.
All it takes is the right stimulus to the psoas to begin to help it release and change. It’s really not that hard. And doesn’t take that long relative to how long it took to get patterned that way.
The psoas muscle, like all muscles, does not work in a vacuum.
Because of our culture’s focus on muscle strength, it’s easy to only think of muscles for recovery. Like massaging, stretching, or strengthening muscle. These are important, but it misses 2 other connected mechanical systems: the neurological system and the skeletal system.
The psoas muscles are in the location of the lumbar plexus of nerves.
The psoas is closely tied to the nervous system and the peripheral nerves that branch down to the legs, to be specific. When there is psoas tension, it can affect the nerves where they branch and lead to various weaknesses in leg muscles, like the glutes, quads, hamstrings, calves, and anterior and posterior tibialis (around the shin).
All muscles are controlled by nerves.
All of the nerves in the lumbar plexus control all of the muscles in the torso front and back, and down the legs. So any tightness, weakness, pain, or numbness you feel in your legs is related to some degree to the nerves that control them. You don’t have to have “nerve” pain, such as numbness, tingling, or burning, to have a nerve-related problem. It can show up as calf cramping, glute weakness, or mild
When a nerve is inflamed, it can restrict the function of a muscle, including and especially the psoas.
Nerves control muscles, so without the neurological (ie. electrical) flow to a muscle, we can’t get to change, at least not fully or for the long-term. This is why massage, rolling, stretching, strengthening, or needling a muscle, including the psoas may only bring short-term results. In order to get
A nerve tells a muscle to pull a bone.
In that order. Without the nerve piece, we can only get so far with muscular changes, including releasing, lengthening, stabilizing, or strengthening. It’s important to address any limitations in the nerve-to-muscle connection so that long-term changes in the muscle can be made. When muscles are loose and pliable, the bones and joints can naturally align.
The psoas muscle needs to be pliable in order to allow your spine, hips, and legs to move properly.
The psoas muscle needs pliability (ie. needs to have “give” to it) in order to keep the pressure out of your low back or tension/pressure out of your leg muscles and joints. This is the opposite of stiffness, which leads to excess compression forces, overworked compensatory muscle, or overloaded joints.
The psoas muscles directly affect your posture.
When the psoas gets shortened or tight, it compresses your spine and also pulls your ribcage forward and down, even in subtle ways. This rounds your shoulders, makes your head jut out, then puts extra pressure on the muscles, nerves, and discs in the neck. This tension makes you have to fight to attain the upright posture we’ve been instructed to have. Rather than use muscular force on the backside to attain that posture, we first need to free the tension on the front that’s creating the problem. Then you’ll have more ease with re-training your posture naturally.
When you feel like you have to put a pillow under your knees to sleep at night, it puts your psoas on slack and relieves your back tension. This signifies psoas tension that needs to be addressed.
Use the pillow to provide more comfort and off-pressure your low back, while at the same time working to release your psoas so you won’t need the pillow any longer. Ultimately, we want to have more lengthening of the psoas, rather than shortening it all the time.
The psoas is an emotional center.
Because it’s part of the soft, front side of the body, the psoas tightens up to protect us from trauma. This includes physical trauma (like a swift, strong, unexpected movement), or emotional trauma (like being in a car accident). Muscle tension can occur as a protective mechanism from both types of trauma, and in the psoas in particular. Our culture (my professions in particular: physical therapy and fitness) tend to encourage people to focus on core strength to create protection. While this is important, if there is already a dysfunction or overstimulation of the psoas and the nervous system, more muscle contraction (ie. strengthening) can feed into the problem instead of resolving it.
There you have it. The psoas is important to focus on in at least 23 ways (I'm sure I'll think of more). If you think you might be having an issue with, or stemming from, your psoas, and/or the nerves surrounding it, here are some ways I can help:
Book a free Inquiry Call here and we can discuss your specific situation. I can help or point you in the right direction based on your needs, energy, and time right now.
If you're a runner, I am starting a brand new program called:
THE 21 DAY RUNNER RESET CHALLENGE: The Simple Roadmap to Release Psoas Tension So You Can Keep Running Longer, Stronger (even if you don’t think your psoas muscle is related to your knee, achilles, hip, back, foot, or form limitations).
If you're interested, email me at drlarajohnson@yellowbrickpt.com.
Get access to my Free Resource Library for stretches, mobility, and techniques here.