Our physical, mental and emotional states are made up of wonderfully complex, interacting systems, but within them some parts seem to play special roles. The psoas muscle is one of those, both on a physical and emotional level. Working therapeutically with the psoas is very powerful, both in terms of reducing stress and anxiety, recovering from trauma, and also reducing physical conditions, especially lower back pain, shoulder and knee pains, menstrual pain and irritable bowel syndrome. It’s the only muscle that connects your spine to your legs, and so is vital for you being able to walk, and it’s also a central part of the body’s stress and fear responses. The more I work with people, the more I’m fascinated by this place. Let’s take a look at what it does and how to work with it.

Structure and walking

First let’s talk about structure. The psoas muscle starts in your lower back, attaching first to the vertebra where your lowest rib attaches (T12), and also attaching to the vertebrae of the lumbar spine beneath that (L1-5). It then runs over  the front of your hips on both sides, and attaches to the top of your thigh bone. On the way it joins with another muscle, the iliacus, which fans out from the inside of your pelvis to the same part of your upper thigh. These are the only muscles that connect your spine to your legs, pulling your legs up and in towards your belly.

That makes these muscles pretty amazing: they are responsible for holding you upright and for lifting your legs! Let’s just say that walking would be a little tricky without them.


Anterior hip muscles. Image by Beth ohara (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons

Anterior hip muscles. Image by Beth ohara (Own work) [GFDL(http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons


Sitting, shortening and pain

But what happens when a person’s life doesn’t actually involve a lot of walking or movement? Spending hours sitting – at desks, in cars, in bars – means your psoas is held in one fixed position a lot of the time. If you’re sitting now, pay attention to the angle between your stomach and your legs. Your thighs are drawn towards your stomach, so your psoas must be tensed, right? It’s a very deep muscle and one that most people have little attention for, so it’s hard to actually feel whether or not its tensed (although you can train that). Even if you can’t feel it, though, being in a sitting position means the muscle is held in a contracted position.

When this happens for many hours a day, the muscle is continually tightened and hardly ever released, which makes it become shortened. This shortening can have different effects, a common one being that it makes your pelvis tilt, so that the front, top part of the pelvis dips forwards. Try it: stand up, but keeping your knees a little pulled in towards your body whilst trying to get your head upright. Can you feel how the pelvis tilts forwards and your lower back now has a stronger arch and is all tensed and crunched together? This is called anterior pelvic tilt.

So what’s the big deal? This shortening and tilting and arching is a massive change for the body. A shortened psoas leads to an incredible range of pains in the body, because of the way it runs from the level of the diaphragm (to which it is attached by connective tissue) to the legs. When it’s pulled together, it affects the areas above and below where it attaches, and can be the root of lower back pain, sacroiliac pain, sciatic pain, disc problems, scoliosis, hip degeneration, knee pain, menstruation pain, infertility, and digestive problems.

Anterior Tilt - Thank you nuchiro.wordpress for this image.

Anterior Tilt – Thank you nuchiro.wordpress for this image.

When the vertebrae of your lower spine are jammed together by it arching, it puts pressure on the discs and nerves embedded within them, which can then have painful consequences that seem to be (and can also be) rooted in the spine, but often actually originate in the psoas muscle. A tight psoas also constricts the organs around it, puts pressure on nerves and interferes with the movement of fluids. It restricts diaphragmatic breathing, by pulling on the tissue of the diaphragm, so that breathing becomes shallower. We will come to what to do about this in a moment, but first let’s look at a second key role of the psoas.

Running and nerves

As well as it’s structural role, the psoas is a key part of our autonomic nervous system (ANS), which is the non-conscious system that regulates many vital functions of your body. The ANS is in turn made up of two systems that work antagonistically. The sympathetic nervous system (SNS) is basically the active one, getting your heart rate up, releasing stored energy, getting your muscles ready for action, and diverting energy away from things like your digestive system. As well as fluctuating rhythmically during the day, it is also activated when you are stressed, afraid or need to meet a challenge: the “fight, flight or freeze” system. The parasympathetic system (PSNS) does the opposite, and is dominant in peaceful, restful times, or when a stressful situation has ended so that systems can rebalance: the “rest and digest” system. It reduces heart rate and blood pressure again, and activates your digestive and immune systems.

The SNS is a hard-wired physiological response designed to meet threats: it involves the release of hormones like adrenalin; your pupils dilate to let in more light; you sweat to reduce the chance of skin cuts; blood vessels near the skin contract to reduce bleeding. And it involves automatic tensing of the iliopsoas muscles, which is the starting point for any action involved in fight/flight/freeze: running away, kicking, curling you into a ball, and bracing your body. This bending/curling of the body happens completely automatically when you are afraid.

There is also a feedback between the psoas and the nervous system, since the lumbar nerve plexus is embedded within the psoas. A tensed psoas influences the operation of the vagus nerve, which is a key part of the PSNS, signalling to your nervous system that you are on a state of alert, and so telling the body to stay in the active/ready mode, and not to relax. Put simply, when your psoas stays tensed, you stay in the fight or flight system.

Fight or flight? Flight!
Thanks to Saul Adereth’s flickr page for this image: https://www.flickr.com/photos/saul_adereth/5151261753

Stress and relaxation

For many people, the psoas and SNS systems are over-engaged, not only because of sitting, but also because of the levels of stress or anxiety involved in someone’s life. We can see this as partly routed in a way of life that is valued highly in many societies today. You’re supposed to do a lot, be busy, achieve a lot, perform highly. This pushes you to stay stuck in the sympathetic nervous system. It’s hard to come down, to change gear, to relax. And that means not alternating between the SNS and PSNS in the way that bodies and minds really need.

A second factor is that the things making people stressed or anxious are not the same as what the system is “designed” for: we’re not dealing with bears and wolves here. Your unconscious system is telling you to fight or run away, but your conscious mind is telling you that it’s probably not such a great idea to punch your colleague/boss/lover in the face. So you need to something else with those feelings. If there is no real outlet for this physical-emotional state, it’s difficult to return to a relaxed state afterwards.

This constant arousal can have a variety of physical effects, including heightened blood pressure, raised adrenalin and cortisol levels, and interference with digestion, leading to conditions like irritable bowel syndrome (IBS). It also suppress our immune response, and reduces our ability to heal from inflammation, which is stimulated by the parasymathetic system. It even increases forgetfulness (because too much cortisol damages the hippocampus in the brain). In addition, muscles have a higher constant level of tension, and breathing is much more shallow and constrained.

On a more psychological level, this constant arousal is what many people experience as chronic stress and anxiety. It can feel like being constantly alert and ready for something bad to happen, or like always having to try hard to prove that you’re good enough, like never being able to relax and be yourself with other people. It’s also exhausting, and can lead to depressive tendencies, since bodies are not capable of sustaining this state and start to desensitize to it, so that things start feeling flat and grey.

In the next article, which you can read here, we’ll look at the psoas in terms of old fears and traumas and at releasing the psoas.