Psoas Muscle: The Complete Guide — Anatomy, Function & Pain

What’s happening with my psoas?

Anatomists, movement enthusiasts, somatic therapists, and many others are endlessly fascinated by the psoas major muscle! Due to its deep location and complexity, we intuitively sense that it’s important. But, its location several fascial layers deep makes it very hard to study. So the fact is, there is still a lot we don’t know about the psoas, its actions, and its functions. Its mysteriousness only makes it more fascinating.

Get to know your iliopsoas complex

Its central location at the core of our body and its circuitous path crossing more joints than any other muscle, means that there is very little that happens in our body that isn’t affected in some way by the psoas major. The psoas major can play a role in core stability, back pain, sacroiliac joint dysfunction, leg and hip pain, breathing issues, postural dysfunction, and many other common experiences. In this article, get to know the psoas major, and its related muscle the iliacus. Find out where these muscles are, what they do, how they relate to common dysfunctions, and what you need to know about them in your yoga practice.

The iliopsoas complex: psoas major and iliacus

Before we get too far into this article, let’s add a layer of complexity. The psoas major muscle by itself is an important part of your core musculature. However, sometimes it functions along with another key core muscle, the iliacus. You might have already seen the word “iliopsoas” which refers to the combined function of these two muscles. While their proximal (upper) attachments are different, their distal (lower) fibers merge together and they share an inferior attachment on the lesser trochanter of the femur. For that reason, they often work together, although not always. So, as we take a deep dive into everything you need to know about the psoas complex, just remember that when I use the word iliopsoas, I’m referring to actions that the psoas major and iliacus do together. Otherwise, for clarity, I’ll refer to each muscle individually by name.

Psoas minor

There is also another muscle that contains the word psoas and is worth mentioning briefly. It’s called the psoas minor muscle. You can see it on one side of the image below. Psoas minor is on the right side as you are looking at the image. This is the left side anatomically speaking. One reason you might not have read or heard much about psoas minor is that, curiously, it’s absent in approximately half of the population. Psoas minor doesn’t share most of its attachments with psoas major or any attachments with iliacus. Its actions are different as well. For those reasons, I don’t cover psoas minor further in this article.

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Anatomy

Psoas major

The psoas major attaches (originates) proximally (above) on the bodies of the vertebrae, specifically the bodies of vertebrae T12-L4. The bodies of the vertebrae are the large round bony parts that the vertebral discs sit between on the spine. The psoas major attachment is on the sides of this structure.

As the psoas major heads down on either side of the spine, it crosses a total of eight joints before heading forward slightly to drop over the front of the pubic bone. It then reaches its distal attachment on the lesser trochanter of the femur. The eight joints that psoas major crosses are: T12 – L1, L1 – L2, L2 – L3, L3 – L4, L4 – L5, L5 – sacrum, sacroiliac joint, and lastly, the hip joint.

Iliacus

Iliacus attaches inside the pelvic bowl onto the inside of the ilium. Specifically, it attaches at the proximal end to the iliac fossa, which is the name for the depression on the inside of the pelvic bowl. The ilium is the large flat bone that sticks up on either side of the pelvis. The attachment of this muscle differs from our normal idea of how a muscle attaches to a bone. In the case of iliacus, the tendinous attachment is actually under the muscle itself. It’s not a long round tube of tissue in the way we normally think a tendon is. As iliacus leaves the iliac fossa it joins with the psoas major to attach distally to the lesser trochanter of the femur.

Iliopsoas

The word “iliopsoas,” as I said above, generally refers to the combination of both the iliacus and the psoas major muscles. In many of their key actions, the psoas major and iliacus work together as the iliopsoas because their fibers merge together toward the bottom (distal) end at about L5 to S2 before they then attach together onto the femur. However, it’s important to remember that the proximal (upper) attachments of iliacus and psoas are very different. Since they share some attachments but differ in other attachments, they likewise work together in some actions but differ in their contribution to other actions.

Anatomical relationships to other important structures

The web of fascial relationships between iliopsoas and other structures is complex and beyond the scope of this article. However, these relationships inform the effects that psoas major and iliacus have on the body as a whole. So, I’ll highlight some of these key connections, with the understanding that the effects of these relationships go far beyond what I can cover in this article.

If we follow the fascia of the psoas major and iliacus muscles from deep to superficial, we find connections with the entire wall of the abdominal cavity. If we follow the fascial connections of psoas major superiorly, we find connections with the crura and other attachments of the diaphragm. Fascial connections from iliacus become continuous with the fascia of quadratus lumborum. If we follow the fascia of the psoas major inferiorly we find connections with the pelvic floor and associated muscles.

What this means functionally, is that excess tension in any of these areas affects the function in the others. This is a more subtle aspect to discern, but definitely worth considering if you’re having any trouble in these associated areas. Iliopsoas position and tension can affect all of the areas that iliopsoas has a connection with. That includes the potential for iliopsoas to both directly and indirectly affect many aspects of our posture and even our breathing.

Actions and effects

Why is it so challenging to measure the effects of psoas major?

The actions of psoas major are complicated. There are many reasons why understanding the activity of psoas in greater detail is challenging. As I’ve mentioned already, psoas major crosses more joints than any other muscle in the body. This makes its path through the body and its effects complex. Additionally, psoas major is several fascial layers deep. This makes it very difficult to attach electromyography (EMG) wires and other measuring devices. The depth means that it is difficult to be sure that measuring devices are actually connected to the psoas major rather than other muscles or connective tissue.

Depth and path of psoas

It’s also very invasive to connect measuring equipment to the psoas. For that reason, researchers who do laboratory research directly measuring psoas activity have to contend with very small sample sizes as understandably it’s difficult to get volunteers for that kind of research. Finally, because of the long and circuitous path of psoas, it’s also very difficult to model its actions in a laboratory setting, although researchers have still tried.

However, the psoas major muscle is arguably the single most important postural and structural muscle in the body. We can see the results of psoas function when we see the grace and lightness of dancers, gymnasts, experienced yoga practitioners, etc. This motivates researchers of all kinds to continue exploring psoas function with the tools that they have. So let’s delve into the actions of the mysterious psoas and take a look at what we know, what might be true, and what we imagine to be true.

Biomechanical actions – What we know

Despite the difficulties with studying the psoas, there are some things we know. The primary action of both psoas major and its partner the iliacus muscle is hip flexion. They are both powerful hip flexors, the strongest hip flexors in the body. The iliacus in particular is dedicated to moving the femur at the hip joint. Short, thick, and powerful, it’s the unsung hero of the iliopsoas. It’s essential for the powerful hip flexion that we need for so many activities.

Hip flexion can look like bringing the femur toward the hip like when we pick up our leg to take a step when walking. It can also look like bringing the pelvis to the femur, like when we’re folding forward in a forward bend in yoga. Researchers studying psoas activity in a laboratory setting found that it is significantly activity in hip flexion, including sit-ups (Juker et al., 1998) and leg raises (Hu et al., 2011; Juker et al., 1998).

Psoas major and iliacus contributions to rotation – What might be true

Both psoas major and iliacus may also contribute some activity in rotation. Juker et al., 1998 reported that psoas in their study was active to some degree in both internal and external rotation (in both seated and standing), but in their particular study, they recorded more psoas activity in external rotation. When exactly the psoas and/or iliacus contribute to rotation is complicated and contingent on the position of the body. Researchers have debated what direction of rotation (internal or external) each aspect of the iliopsoas might contribute to and under what circumstances. Tom Myers makes a convincing argument in his article ‘The Opinionated Psoas’ that any contribution of the psoas major to internal or external rotation is dependent on the position of the femur, the knee, and the lower leg below (Myers, 2014).

Psoas major and iliacus contributions to stability

Stabilizing the connection of upper to lower body

Iliacus and psoas major lie on either side of the sacrum, and therefore our center of gravity. Combined as the iliopsoas, the psoas and iliacus are the epitome of our “core” muscles. That means they are essential for maintaining stability in our body as well as a key to controlling big movements. The psoas forms one of the deepest connections of our upper body to our lower body. Psoas major is one central and critical part of stabilizing the connection of the pelvis to the spine. Researchers have measured significant activity of psoas muscle fibers in activities like push-ups where we need a stable core (Juker et al., 1998).

Stabilizing the lumbar spine

As I mentioned above, the circuitous path of psoas major and the number of joints it crosses make understanding all of its contributions to actions, complicated. One point of contention among researchers is exactly how psoas affects the lumbar curve. The psoas crosses all lumbar vertebral joints, so it makes sense that it would affect those joints. However, researchers have noted that the path of psoas major is not a straight line (Santaguida and McGill, 1995; Myers, 2014). Additionally, the upper fibers of psoas major are more vertically oriented and travel a longer path compared to the lower fibers (Santaguida and McGill, 1995).

Upper and lower fibers of psoas major

Because of the change in the way the sections of psoas major fibers pull as we travel up the lumbar spine, it’s possible for the lower fibers of the psoas major to contribute to different actions on the lumbar spine than the upper fibers. It’s possible for the lower fibers of psoas major to pull the lower lumbar vertebrae into a stronger lordotic curve. But, because of the direction of pull and the fiber direction, it’s possible for the upper fibers of psoas major to actually reduce the amount of lordotic curve. Both of these actions depend of course on the position of the body and the tension in the many other muscles that affect the spine and lower back.

Psoas influence on lumbar spine in movement

Researchers have suggested that the organization of psoas major fibers and tension on our lumbar spine contribute to stabilizing the lumbar spine when we are sitting upright (Penning, 2000; Juker et al., 1998; Santaguida and McGill, 1995). Interestingly, Hu et al., 2011 found in their research study that in addition to the iliacus and psoas major (both aspects of the iliopsoas) contracting on the lifted leg during a standing leg raise, the psoas major also contracted about the same amount on the opposite leg (the one the person was standing on) during a standing leg raise. The authors hypothesized that this action helps stabilize the lumbar spine during hip flexion. Additionally, the psoas major is also well-positioned to contribute to lateral flexion and lateral stability of the spine (Santaguida and McGill, 1995).

Psoas major and iliacus activity in functional movement

Iliopsoas in gait

Functionally, the psoas muscle was at a minimum designed to effectively and efficiently put one foot in front of the other, which we know as walking. The technical word for walking is gait. One research team created a biomechanical model that showed the essential nature of psoas major in gait. If researchers stopped psoas function in their model, lumbar lateral flexion and pelvic rotation were restricted to the point that their model could not walk (Sanaka et al., 2022).

When combined into the iliopsoas, psoas and iliacus work together to stabilize the pelvis and hips as well as create specific actions. This stabilization is especially essential when we’re doing activities that involve holding our weight on one leg referred to as “single-leg stance activities” (Lifshitz et al., 2020). A single-leg stance happens briefly during gait, every time we take a step and shift our weight from one foot to the other.

A model for psoas in gait

Researchers developed a biomechanical model showing that the psoas major not only helps flex the hip but also causes the lumbar spine to bend sideways toward the same side during gait (walking) (Sanaka et al., 2022). In this model, psoas contracted on the same side as the foot on the ground (called the stance side) and caused the lumbar spine to bend laterally. Then trunk movement created inertia which lifted the opposite leg up. Psoas contraction then caused the lumbar spine to rotate slightly toward the stance side, helping the pelvis shift forward. Other muscles then assisted in swinging the lifted leg forward (Sanaka et al., 2022).

Aging and gait

Schloemer et al., 2017 found age-related differences in muscle recruitment during gait between healthy younger and older adults. Older adults recruited less from iliacus and psoas, but more from gluteus maximus (Schloemer et al., 2017). This change in muscle recruitment is one example of how moving less from our true core muscles (iliacus and psoas major along with a few others) can potentially affect both efficiency of movement and stability.

Iliopsoas and other functional movements

Iliopsoas is also essential for actions that relate to or build on walking. Contracting the iliopsoas is necessary for kicking, for example (Lifshitz et al., 2020). We also engage iliopsoas when we run, hike, or climb stairs.

Maintains pelvic balance and sacroiliac joint stability

As I’ve said many times in other articles, no muscle works alone. That includes psoas major. One stability function of psoas major is to work with piriformis to maintain the correct balance of tension at the sacroiliac joints (SI joints). The sacroiliac joints are the points on either side of the pelvis where it connects to the spine via the sacrum. It is the relationship between the psoas and the piriformis muscle that most directly affects the muscular balance at the sacroiliac joints, along with some help from other associated muscles (the deep six lateral rotators) at the back of the pelvis. The ligaments and other connective tissue contribute, but muscularly the balance of tension between these two muscles is critical for maintaining the right balance of stability and mobility at these joints.

Affects the position of the pelvis more generally

We already discussed the fascial connections between aspects of the iliopsoas and other structures. Because of the fascial connections that psoas major has to other structures and the interrelated nature of all of our core structures, psoas major affects the position of the pelvis generally as well as the position and tension of structures above and below. The iliopsoas has a close functional relationship to the abdominal wall, diaphragm, quadratus lumborum, pelvic floor, and piriformis. Together, these connections can affect the entire core of the body, including the back.

Additionally, since the iliopsoas is a hip flexor, it’s always in relationship to its antagonists, the hip extensors. Hip extensors include gluteus maximus, the posterior aspect of gluteus minimus and medius, as well as the hamstrings and adductor magnus. This balance between hip flexion and extension can also influence the amount of tension across the back. The interconnected nature of all of these structures and their influence on tension across the back is one reason why diagnosing the source of generalized back pain is so difficult.

Psychological and emotional effects of iliopsoas – What we imagine

Although much harder to measure, it makes sense that iliopsoas would have a relationship with our psychological, emotional, and energetic states. Contraction of the iliopsoas takes us into a fetal position, so in that way, we could imagine that it has a relationship with our fight, flight, and freeze response. Tension and activity of iliopsoas are affected by feedback from our autonomic nervous system (Pulvermacher, 2021). Iliopsoas could be considered a physical aspect of uddiyana bandha. Ilopsoas crosses the pelvic bowl, which is cross-culturally the origin of energetic circulation. In yoga philosophy, it crosses the three lowest chakras. Finally, emotionally, the area crossed by iliopsoas is often one we describe with language like having gut instincts or butterflies in our stomach, suggesting an emotional connection to deep layers of myofascial structures in this area.

Iliopsoas muscle issues

When we consider iliopsoas muscle issues, there is an important caveat that we should keep in mind. That is, as I reminded you earlier in this article, no muscle exists in a vacuum. We are complex beings full of interrelationships at all times. If your psoas major muscle and or iliacus are contributing to postural issues or pain patterns, it’s unlikely that they’re working alone.

Additionally, it’s tricky to self-diagnose an issue with iliopsoas because sensation/pain doesn’t necessarily equal either tightness or weakness, or even necessarily mean that where you’re feeling sensation is the source of that discomfort. It could be weakness, tightness, both, neither, or something else besides the iliopsoas entirely. Bodies are complicated and if there is an issue with the iliopsoas then it is one part of a larger pattern. Issues in the body are rarely an issue with just one muscle.

Do I need to strengthen or stretch my psoas?

Assessing your iliopsoas properly is essential before you decide how to treat it. Some of you may show up to this section with the idea that your iliopsoas is tight. Some of you may be wondering how to strengthen it. Keep in mind that your iliopsoas muscle may be weak because it is too tight! Applying strengthening techniques because you think it is weak may be the wrong thing to do if it’s weak because it’s already too tight. You’re then tightening a muscle that is already too tight.

For those reasons, diagnosing a psoas-specific or iliacus-specific issue is very difficult. If you are experiencing pain or loss of function that you think might be related to an aspect of iliopsoas, consider consulting an experienced massage therapist, structural integration therapist, osteopath, or another professional who can help you assess the issues you’re experiencing in a holistic way.

Now that we have established those caveats, let’s talk a little about tightness, stretching, and strengthening with respect to the psoas major and/or the iliacus muscles.

Psoas major and iliacus tightness

One of the most common questions I get about psoas major and iliacus issues is, if I think that iliacus and/or psoas are tight, how do I stretch my psoas? Let’s start with why the two parts of the iliopsoas (iliacus plus psoas major) might get tight.

Walking, running, and cycling

The iliopsoas sits at the core of our body and in a sense, the center of our movement. The most fundamental movement we do is walking. Activities that create, in a sense, an excess of this type of movement such as running and cycling, can contribute to tightening the psoas major, iliacus, and other muscles, like rectus femoris, whose action is hip flexion. Of course, these movements are often layered on top of patterns of tightness that may already be in place, exacerbating the problem.

Sitting

Additionally, iliopsoas is active and contracted to a degree when we sit. It’s not contracted in the same amount when we sit as it is if we run, cycle, or do a boat pose. However, sitting is something that many of us do for many hours in the day. So, this very simple activity has the potential to increase the overall tension in the iliopsoas muscle. People who sit a lot for work or other reasons, may have a chronically shortened iliopsoas muscle (as well as other postural compensations). This means that muscle activity is required, even if just minimally, to maintain this position and relationship between the spine, pelvis, and femur. This essentially happens because the hip is held in a partially flexed position for long periods of time.

If you combine walking, running, cycling, and sitting together, you cover a large portion of the population. While these are not the only activities that can cause tension in the iliopsoas, they are some of the most common. Walking, running, and cycling are some of the most common physical activities that people do. Sitting for long periods represents what a large part of the population ends up doing between their movement activities. When you combine all the hours we spend doing these activities, you can imagine how we might end up with a tight iliacus and psoas major muscle.

Symptoms of a tight psoas major and/or iliacus muscle

So how do you know if your iliopsoas is tight? The symptoms of a tight psoas muscle can certainly vary. Some may be more obvious than others. The real difficulty when assessing your problem, a client’s problem, or a student’s problem, is that rarely, is any problem the result of an issue with just one muscle. Additionally, the psoas has become a catch-all. What I mean by that is because of all the media attention the iliopsoas gets these days, people have started jumping to the conclusion that any problem in the back, hip, or surrounding areas is because of the iliopsoas. It may be, just don’t jump to any conclusions too quickly.

Having said that, below is a list of things that may lead you down the path of recognizing a tight iliopsoas muscle. Just remember that if psoas and/or iliacus are involved in most of these symptoms, then there is likely a complex whole-body issue(s), not just an issue with iliopsoas.

Symptoms sometimes associated with iliopsoas tension and tightness:

• Lower back pain
• One or both sides of the pelvis tilted forward more than average
• Hyperlordotic curve in the lumbar spine (May go with the list item above)
• Difficulty lifting your leg
• Knee pain
• A functional leg length difference
• Constipation
• Menstrual cramps
• The feeling that your legs are weak
• The feeling of having a “compressed” hip joint
• A general feeling of fatigue
• Restricted breathing

Keeping mobility in your iliacus and psoas

Before we talk about stretching your psoas and iliacus, let’s talk about how to avoid a tight iliopsoas. The best thing you can do is avoid problems with your iliopsoas muscle in the first place of course. Here are a few things that you can do to reduce creating tightness and tension in your iliopsoas muscles:

• Avoid sitting for long periods
• Add lumbar support when you do sit
• Back off of extreme exercises that tighten the iliopsoas
• Be consistent with doing the poses in your yoga practice that stretch the iliopsoas
• Get a professional massage
• Pay attention to your hips and pelvic freedom generally, and change your activities and/or sitting habits when you notice tension creeping in

Stretching your psoas major muscle

There is some debate as to whether you can truly stretch your psoas major enough to undo tension in it. Part of the reason for this is because of the depth of this muscle. Stretching psoas major means that you would need to take your legs into hyperextension. This is exactly why you often see some form of lunges used to stretch the psoas muscle.

Additionally, in order for you to actually stretch psoas major, all of the more superficial muscles have to have sufficient length to allow you to get to the psoas and lengthen it. It’s not that hyperextension isn’t possible, it obviously is. It’s also not that you can’t stretch the psoas at all when your leg is in hyperextension, you can. The question is, how effective is it to stretch your psoas major when the impact of the stretch itself may be impeded by more superficial short, tight tissues like rectus femoris? And, additionally, the effect of the stretch may be minimized by psoas’s depth and the difficulty isolating that tissue. Having said all of that, there is no harm in trying to generally maintain the openness of the tissues on the front of the body, including the iliopsoas.

Stretching iliacus and psoas

Some experienced movement professionals have weighed in on how you might target iliacus and psoas major in a stretch. Tom Myers of Anatomy Trains suggests “A lunge, or warrior one pose could stretch the psoas major as long as the lumbar vertebrae are not allowed to fall too far forward in the lunge, and the pelvis is kept square to the leg in front.” In order to put more pressure into iliacus and focus on stretching iliacus in a warrior one pose, Tom suggests “letting the knee of the extended/back leg turn medially toward the body, [and] letting the heel fall out. Moving the ribs away from the hip on the same side will emphasize this stretch.” Liz Koch in her book celebrating the psoas major (The Psoas Book) includes many activity suggestions for maintaining suppleness and resiliency in psoas major.

Releasing the psoas muscle

Another phrase that you might see related to psoas major is the idea of releasing the psoas. So, what about releasing the psoas? The tricky part about this as I’ve explained, is that it can be difficult to figure out if one or both of your iliopsoas muscles are short and tight and would benefit from releasing. Remember the iliopsoas muscles are a pair. You have a set on both the right and left sides of your body.

Iliacus and psoas can do similar or different things on the two sides of our body. It is possible for iliacus to be short and tight on one side while the psoas major on that same side is not short and tight. It’s also possible for the iliacus and/or psoas major on the right and left sides of your body to be in different positions. One side may be short and tight, while the other side is not. This is often true if, posturally, your pelvis is in torsion and/or you experience one-sided sacroiliac joint pain or issues. So rebalancing the tension in your iliacus and psoas major muscles in both the anterior/posterior and right/left relationships might be a better intention than releasing your psoas.

Strengthening psoas

So what about strengthening your psoas? If we’re talking about strengthening psoas major, it’s important that we remember the numerous joints it crosses and the complexity of the path it traces. Additionally, because so many of the activities that we commonly do shorten the psoas major, it’s much less likely that we’ll need to strengthen psoas as opposed to lengthen it. Finally, there’s a current trend to emphasize strengthening muscles as the solution to all pain and biomechanical issues.

While the reasons for that emphasis on strengthening are a different topic, the important part to understand is that when we try to strengthen a muscle with so many different connections and directions, it can have unintended negative consequences that are hard to predict. A posture like boat pose engages, and therefore arguably strengthens, the deep hip flexors including psoas major and iliacus. However, I think that it’s rare to come across a situation where directly trying to strengthen the psoas major is the best solution to an issue with this muscle. I discuss this in more detail in the next section.

Cultivating a relationship with iliopsoas

When it comes to addressing the feeling that something is off with your iliopsoas, I prefer the intention to cultivate a relationship with iliopsoas, and psoas major in particular, rather than either trying to stretch or strengthen your psoas.

The first step in cultivating that relationship is finding your psoas major and iliacus muscles. I know from many years of teaching that most students don’t know where their psoas major or iliacus muscles are. When I ask students to point to their psoas during a workshop, students point just about everywhere between their neck and their knees. A relationship with your iliopsoas starts by just getting to know the location of your own anatomy. So let’s start by finding your iliacus and psoas major muscles.

Finding your iliacus muscle

For various reasons, the psoas major muscle has become popular, but many people have never heard of the iliacus. I recommend starting your palpation exploration with iliacus as it’s often easier to find. Most people lie down on their backs and bend their knees to find the iliacus and psoas major muscles. You can apply the same techniques I am about to describe. But I suggest that you sit in a chair or sit on the ground with your legs out in front of you. If you’re pregnant, have irritable bowel syndrome (IBS), Crohn’s disease, or other issues with any organs in the area, have a professional do this or do not do this at all.

Steps for palpation

First, identify your anterior superior iliac spine (ASIS image below). From there, you need to curl your fingers onto the inside surface of your pelvis. You don’t have to go in too far, about an inch or so should be enough to check that you are on the right spot. It’s helpful to round forward a little in your spine to make sure your abdominal muscles are soft, and not contracted. After you have your fingers on the inside surface of your pelvis, slowly lift your leg up slightly on the same side. Think of lifting your entire foot off the floor. It won’t take much for a muscle to contract under your fingers. When it contracts it should push your fingers forward slightly and inward toward your midline. Note that your fingers are on the inside surface of your pelvis.

Finding psoas major

If you want to find your psoas major muscle, start from the same location you left off when finding your iliacus. Then slowly slide your fingers toward your midline. When you try to lift your entire foot this time, your psoas major muscle will feel more like a line of tissue that is running vertically rather than flat and pushing your finger inward. Note that the fingers are off the inside of the pelvis and now heading in the direction of the spine.

Observing your iliacus and psoas

Once you’ve located your iliacus and psoas major muscles, the next step is getting to know what your own iliopsoas feels like most of the time. Another thing I notice, is that many yoga students have no strong proprioceptive connection to the area of their body where psoas major and iliacus are located, what I’d consider their core. How are you going to stretch or strengthen something you can’t even sense? Get to know your iliopsoas on regular days. Then you’ll have a better sense if something is “off” in your body and have a better intuition about what you might want to do about it.

As you palpate your iliacus and psoas major muscles, go gently with a light touch. First, just notice what you feel. Observe before trying to change anything.

Here are a few things you may want to pay attention to:

• Do these muscles feel differently on one side than the other?
• Does it feel like your two psoas major muscles are in the same place relative to your spine or are the right and left sides different?
• Is one side of your iliacus or psoas major larger than the other?
• Is one side of your iliacus or psoas major more tender than the other?
• Did you have a harder time lifting your leg on one side when it had pressure on the muscle?
• Did you notice any other differences between the two sides?

Manual treatment of iliacus and psoas major

Once you’ve found your iliacus and psoas major muscle and you’ve developed a sense of what normal feels like in your body, you can then develop a sense of when something feels off. That’s when you can use strategies to bring your body back into balance. Research studies suggest manual therapy, physical therapy, and mobilization exercises are all useful strategies to address iliopsoas issues (Lifshitz et al., 2020). This is, of course, the domain of a professional, but there are a variety of simple things you can do yourself that may make a difference in your particular situation.

Stretching versus treatment

It’s important to know that there is a difference between treating your iliopsoas with your own fingers and stretching your iliopsoas. Specific manipulation is more direct and can address problems in a more nuanced way. If you are unsure at any point in the process, please refer to a professional for direct treatment and manipulation of your iliopsoas muscles. Stretching your psoas and iliacus muscles may be helpful, but it is a more general treatment and often more helpful at maintaining what is gained by direct treatment.

It’s also important to remember that, once you’ve identified where your iliacus and psoas are, that sensation, pain, etc. in the area of your iliopsoas doesn’t necessarily mean that it’s tight and it doesn’t always mean that it is weak. It does suggest, however, that something is out of balance. But, the whole picture of which structures are out of balance is usually far more complex than people want it to be. Iliopsoas is, after all, a complex core structure.

Don’t neglect iliacus

In my own anecdotal experience, iliacus is a key part of issues with the whole iliopsoas as much as or even more often than psoas major. Iliacus is also usually easier to access and find. Additionally, working with psoas major is trickier. And, unless you’ve had some in-person coaching on how to treat your own psoas major, it’s often best left to professionals. You can inspect and explore both the iliacus and psoas major. But, with respect to self-treatment, I suggest you start with the iliacus portion of the muscle.

Once you have found your iliacus, gently press and release as much of the muscle as possible. Go slowly and stop if at any point it feels too painful, especially if it’s sharp or nervy pain. Contract and relax along the way so you know you are still on the muscle. Press a little more firmly when the muscle is relaxed, particularly on areas that are more tender than the area that surrounds that tender spot. You can also press and hold these areas for a longer period of time, but not for more than about 30 seconds. You can also hold these areas and get your iliacus muscle to contract while you are holding it. This is a basic treatment.

Explore multiple treatment strategies

As you work with self-treatment of iliacus and explore self-palpation of iliacus and psoas major generally, it’s important to remember that avoiding iliopsoas muscle issues, to begin with, is ideal. So, be sure to identify and adjust other activities that may be contributing to a problem along with any self-treatment strategies that you explore. Additionally, issues with tension, tightness, and/or imbalance in the core structures of our body, like the iliopsoas can take time to resolve. So, be patient as you explore treatment strategies, whether that’s stretching, adjusting daily habits and activities, or direct manual treatment. It may take time to experience a change in the iliopsoas.

Cultivating a relationship with the psoas muscle in movement

Whenever I talk about the iliopsoas muscle in workshops, I say something like: Before you decide whether you need to stretch or strengthen your iliopsoas, you should have a relationship with it. What do I mean by that? I mean that you should have some sense of what it means to connect to this muscle in a way that helps you create movement from it.

What makes this difficult is that your iliopsoas muscle is not like your biceps that you are able to feel, see, and touch easily. The sensory response from your biceps muscle is different from the sensory information that you might get from your iliopsoas muscle. Your relationship with your iliacus and psoas major muscles is one that develops over time. How do you do this? You start with intention.

Relating to iliopsoas in sun salutations

As a yoga teacher, I do exercises of palpation (touching) with the iliacus and psoas major muscles as I described above. But by far, the best place to start the intention to engage the iliacus and psoas major in movement is in sun salutations. Here’s me leading sun salutations in a London workshop so you get a sense of what I’m talking about.

These same principles could and should be applied to lifting up and jumping back if you do a vinyasa-style practice. Even though you’re using your arms to lift up, incorporate the intention of connecting that lift to your lower abdomen, particularly your iliopsoas muscle. As you build a better relationship with iliopsoas, you’ll start to know what it needs and when it needs it.

Psoas, iliacus, and pain

Iliopsoas syndrome

As I’ve already explained in this article, understanding the iliopsoas is complicated. And, that includes understanding the impacts that tension, tightness, and other issues with the iliopsoas have on pain and dysfunction. There are many different types of pain and dysfunction that iliopsoas can be involved in, including things like low back pain, groin injury, pelvic pain, hip pain after surgery, and hip-snapping (Lifshitz et al., 2020). That list is not exclusive, however.

Common symptoms of iliopsoas issues

There are common symptoms that tend to group together and indicate that iliopsoas may be a part of whatever issue someone is experiencing. Medical professionals often refer to that group of symptoms as “iliopsoas syndrome.” However, researchers report that the term iliopsoas syndrome is really a catchall for any kind of tendinopathy and non-specific iliopsoas-related issue (Lifshitz et al., 2020). A syndrome is really just a medical way of describing a group of common symptoms. It does not describe one specific disease or condition. There may be many causes of the symptoms.

The group of common symptoms that are commonly referred to as iliopsoas syndrome include, but are not limited to:

• Pain in the lumbosacral region (where the lumbar spine joins the sacrum) generally, and when sitting and standing
• Pain in the lumbosacral region that worsens when bending at the hips, walking, climbing stairs, squatting, or sitting
• Gluteal and buttock pain generally, that sometimes radiates to the knee
• Pain in the groin area
• Lower abdominal pain
• Sometimes hip and thigh pain

If you are experiencing this constellation of symptoms, seek out an appropriate medical professional for a diagnosis.

Iliopsoas and low back pain

One specific pain issue that I’ve already alluded to that the iliopsoas is often associated with is low back pain. The iliopsoas is without a doubt a very important postural and structural muscle. When there is low back pain, we often look to posture as a culprit of this type of chronic pain. The iliopsoas should therefore be part of the assessment of low back pain and its potential cause. However, so far, there is no research that directly points to a relationship between low back pain and the iliopsoas muscle.

Iliopsoas doesn’t work alone

The topic of lower back pain is complex and convoluted. Good assessment is the key to addressing all of the possible factors that may contribute to lower back pain. We should not assume that the iliopsoas muscle is the key to resolving this problem. We may need to look at other muscles such as the quadratus lumborum, or even other hip flexors such as rectus femoris, adductors, and tensor fascia latae. These muscles as well as others can also contribute to a pelvic position that is related to lower back pain.

With respect to lower back pain and the iliacus and psoas major muscles, keep these in mind as one contributing factor. But don’t get drawn into the popularity of the muscles and assume that iliopsoas lives in a vacuum all by itself. Take a broader perspective, but definitely consider your iliopsoas muscle along with others.

References

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