Psoas Muscle: What It Is, Where It Is and What It Does

The psoas muscle is a deep hip flexor that joins your lower spine to the top of your thigh bone. If you have heard "your psoas is tight" and wondered what that even means, you are in good company. This page explains what the psoas muscle is, where it sits, what it does, and why it gets blamed so often.

What is the psoas muscle?

You have two psoas muscles, one on each side. The full name is psoas major, said "SO as". It is long, thick and strong. It starts beside your lower spine, travels down through the belly and the pelvis, and ends on a bony knob at the top of the thigh bone.

Beside it in the pelvis lies a flat muscle called the iliacus. The two meet and share one tendon at the thigh. Together they are called the iliopsoas. When people say "hip flexor", they often mean this pair. If you want the exact points where the muscle attaches, our page on the psoas muscle origin and insertion lays them out.

Where is the psoas muscle?

Deep. That is the honest answer. It sits behind your belly and gut, in front of your lower spine. It then curves over the front rim of the pelvis and passes close to the hip joint on its way to the thigh.

Because so much lies in front of it, you cannot press on it from the outside the way you can with your calf. Most of what people feel is a general sense at the front of the hip, in the groin, or across the low back. That sense can come from many places, so it helps to hold the word "psoas" a little loosely.

Psoas muscle function: what it does

The psoas muscle has two main jobs, and they work together.

The first is to lift the thigh. When you climb a stair, step off a curb or swing your leg forward to walk, the iliopsoas helps bring the thigh up toward your trunk. It also works the other way round. If your legs are fixed, as when you sit up from lying down, it helps bring the trunk toward the legs.

The second is to help steady the spine and pelvis. Because the psoas attaches to your spine, it takes part in holding your trunk upright over your hips. That matters in sitting, in standing and in walking. It is one part of a team. Your deep belly muscles, back muscles, buttocks and breathing muscles all share the job. No one muscle holds you up alone.

Why long sitting is linked with a feeling of tightness

When you sit, your hips are bent. Your psoas rests in a shortened position, often for hours. Then you stand up, and the hip is asked to open out. Many people notice a pull at the front of the hip or a stiff low back at exactly that moment.

Researchers do not agree on how much of this comes from the muscle itself. Part may be habit: the body gets used to one position. Part may be guarding, where you tense around a sore back or hip and the psoas joins in. Part may simply be that you stayed in one place. What helps most people understand it is that the feeling is real, and that it usually changes when the way you sit and move changes.

For a closer look at the causes, see what causes a tight psoas muscle. If the feeling has turned into an ache, our guide to psoas muscle pain covers where it is felt and when to see a doctor.

Why the psoas is hard to feel, and hard to "stretch"

Two things make the psoas tricky. It is deep, so you cannot reach it directly. And it is crowded: the hip joint, the nerves of the leg, the gut and the kidney all sit nearby. A pull in the front of the hip may come from any of them.

That is also why the popular idea of "releasing" the psoas by one big stretch often disappoints. Pulling hard into a guarded muscle tends to bring more guarding, not less. You will sometimes see claims online that the psoas stores emotions or trauma. The evidence for that is weak, and you do not need to believe it to move more comfortably.

Back and hip complaints are very common, and the cause is often not one muscle. Low back pain affected an estimated 619 million people in 2020 (WHO, 2023). Most cases cannot be traced to a single structure. So hold "it must be my psoas" lightly. It is an idea to explore, not a diagnosis.

A gentler way in: notice how the whole area moves

If the psoas is hard to reach, try starting somewhere easier to feel. Lie down on your back, knees up and feet resting flat. Let your pelvis roll a tiny bit, as if rocking a bowl of water. Where does your lower back touch the floor, then lift away? What do your legs do? Do your ribs and breath join in?

You are not trying to find the psoas. You are noticing how pelvis, spine and legs share one movement. When that sharing gets clearer, the front of the hip often has less to do alone. Our somatic exercises for beginners lesson walks through this kind of exploring, and the Feldypedia article on hip stiffness and limited mobility shows how the hips and trunk work as a team.

Where Feldenkrais® fits

Feldenkrais® is a way of learning through movement. Its group lessons, called Awareness Through Movement®, ask you to move slowly and comfortably and to notice what else joins in. When a student tells me "my psoas is tight", I often see them holding the belly and back firm as they sit or stand. A lesson slows everything down until that holding becomes easy to sense. Then other parts can lend a hand. Nobody pulls on a muscle here. Our Feldypedia entry on the Feldenkrais Method explains how a lesson works, and Feldy offers short daily audio lessons you can follow at home. This sits alongside medical care, never in place of it.

Find where to start

Several gentle methods offer a steady routine for moving the hips and back with attention. Each suits different people, so pick the one you will keep coming back to.

Not sure which movement method fits you? Take the 60 second Movement Match quiz, three questions, then one method to try first.

Common Questions about the psoas muscle (FAQ)

What is the psoas muscle?

The psoas muscle is a long, deep muscle on each side of your body. It starts beside your lower spine, runs through the belly and pelvis, and ends on the top of your thigh bone. Its proper name is psoas major. It is one of your hip flexors, the muscles that bring the thigh and the trunk closer together.

Where is the psoas muscle?

It lies deep inside you, behind your belly and in front of your lower spine, then crosses the front of the pelvis toward the groin. You cannot see it or press on it from outside, because the gut and other tissues sit in front of it. That is why people locate it by a general feeling in the front of the hip or the low back, and why that feeling is easy to misread.

What is the function of the psoas muscle?

Its main job is to lift the thigh, as when you step up a stair or take a stride. It also helps hold the spine and pelvis steady in sitting, standing and walking, working with the iliacus muscle in the pelvis. Together the two are called the iliopsoas. Many other muscles share these jobs with it, so no single muscle works alone.

Can the psoas muscle be tight, and why does everyone say mine is?

People use tight to mean a pulling, shortened or guarded feeling at the front of the hip or in the low back. Long sitting is linked with it, and so is guarding after a sore back. But the psoas is so deep that nobody can confirm it by touch, so the word is often a guess. A clinician can examine you if the feeling bothers you or does not ease.

How do I stretch the psoas muscle?

It is hard to reach directly, because it sits so deep and many other muscles move with it. Pulling hard into the front of the hip often brings more guarding, not less. A gentler start is to notice how your pelvis, spine and legs share a movement, and to lengthen your sitting and standing with frequent changes of position. Slow, comfortable movement usually suits an irritated hip better than force.

How often should I move if I sit a lot?

Short and often works well. Stand up, walk to the window or change how you sit every half hour or so, for a minute or two. A few slow, easy hip movements during the day add to that. There is no perfect number, so let comfort set the pace.

How long until the psoas feels less tight?

It varies. Some people feel the front of the hip ease after a day of more varied sitting and walking. For others it takes weeks of easy repetition. If nothing shifts over several weeks, or it feels worse, have a clinician examine it.

When should I see a doctor about pain at the front of my hip or groin?

See someone promptly for pain with fever, pain after a fall, sudden severe pain in the belly or groin, a bulge in the groin, or numbness or weakness in the leg. Hip joint, hernia, kidney and appendix problems can feel like a tight psoas. Gentle movement sits alongside medical care and never replaces it.

How is the psoas different from other hip flexors?

The hip flexors are a group. The psoas is the deepest and is the only one that reaches up to the spine. The iliacus lies in the bowl of the pelvis and joins the psoas at the thigh. Muscles at the front of the thigh, such as the rectus femoris, also bend the hip, but they work closer to the surface and are easier to feel.