Quadratus Lumborum Pain: The Deep Muscle Behind a One Sided Ache

Quadratus lumborum pain is one of the classic shapes of one sided low back ache: a deep, nagging discomfort that lives just above the belt line, on one side, and gets louder after standing around, a long drive, carrying a bag on one shoulder, or an afternoon glued to a chair. The quadratus lumborum, QL for short, is a flat, deep muscle you cannot poke directly from the surface, which is part of why it confuses people. This guide walks through where it is, what it actually does all day, why it complains, and a way of helping that does not involve attacking the muscle.

Where the quadratus lumborum sits and what it does

Picture the space on your back between the top of your pelvis and your lowest rib, beside the spine. The QL fills that space. It attaches below to the iliac crest, the bony rim you feel when you put your hands on your hips, and it runs up to the twelfth rib and to the sides of the lumbar vertebrae. There is one on each side.

Its job description is longer than its size suggests. It takes part in side bending, tipping your trunk toward one side or hitching one hip up. It helps steady the pelvis when you stand on one leg, which you do with every single step. And it has a quieter role in breathing: by anchoring the twelfth rib, it gives the diaphragm a stable rim to pull against. So the QL is involved when you walk, when you reach sideways, when you carry anything asymmetrical, and, in a small way, every time you breathe.

Because the top of the pelvis is a busy neighbourhood, QL ache often overlaps with the territory covered in our guide to iliac crest pain, and it works underneath the broad connective sheet described in our page on thoracolumbar fascia pain. These structures are neighbours, and they often ache together.

What makes the quadratus lumborum complain

Here is the honest pattern behind most QL trouble: not one dramatic injury, but hours of low level effort that never ends. Standing with your weight parked on one leg asks one QL to hold the pelvis level, quietly, the whole time. A shoulder bag on the same side every day, a toddler always on the same hip, a car seat that tilts you subtly, a desk setup where you lean toward the screen: each one hands this muscle a small job that it never gets to put down. Muscles are built for effort followed by rest. A muscle asked to work at three percent, forever, starts to ache, and that ache is information rather than damage.

One more honest note. You cannot reliably diagnose from the inside which structure is producing your pain. One sided low back ache can come from the QL, but also from joints of the spine, the sacroiliac area, the hip, a disc, or occasionally something visceral like a kidney. This page describes a common muscular pattern, not your diagnosis; a clinician who can examine you is the person to make that call. Whatever the source, you are in very large company: low back pain affected around 619 million people worldwide in 2020 (WHO, 2023).

A tired quadratus lumborum needs colleagues, not a beating

A lot of advice for QL ache goes straight at the muscle: press it, stretch it hard, dig a ball into it. Those sensations can be pleasant, and enjoying them is fine. But a muscle that aches from constant quiet work does not primarily need more input. It needs the rest of you to share the job.

That reframe is the heart of the Feldenkrais Method®. Instead of asking "how do I loosen this muscle", it asks "why is this muscle the only one doing this work". If your ribs move freely, if your pelvis can shift weight through both legs, if side bending is distributed along the whole spine instead of hinging at one spot, the QL's workload drops on its own. In slow, attentive lessons you explore how you stand, sit, carry and breathe, and the nervous system quietly updates its habits. Nothing is forced to let go; the effort simply becomes unnecessary. You can read more about how persistent back pain behaves in our Feldypedia article on chronic lower back pain.

Small experiments for an overworked QL

You do not need a protocol to begin; you need curiosity about your own habits.

Notice your standing. Next time you wait in a queue, sense which leg carries you. Then let your weight drift slowly to the other leg, and back, several times, like seaweed in water. You are not hunting for a correct stance; you are reminding your system that both sides exist.

Vary the carrying. Swap the bag shoulder. Move the strap across your body. Carry the shopping in two lighter loads instead of one heavy one. Asymmetry is not a crime, but permanent asymmetry is a standing order for one QL.

Let your breath reach your sides. Sitting comfortably, rest a hand on your lower ribs on the achy side and feel whether the breath widens there. A few minutes of easy attention like this often does more than effortful stretching, because the QL and the breathing apparatus share the twelfth rib.

Interrupt the long holds. Long drives and long sits are the QL's least favourite thing. A thirty second wriggle, a slow side to side shift in the chair, a walk to the kitchen: these tiny interruptions matter more than their size suggests.

For a fuller, voice guided way into this kind of resting attention, our lesson page on how to relax your back is a natural next step from this guide. And if you would like this approach as a daily practice, Feldy's free trial opens with short, calm audio lessons you can do on the floor at home, many of which teach exactly this skill of spreading effort more evenly through yourself.

Clinical care belongs in this picture too. If your pain is strong, persistent or worrying, a doctor or physiotherapist can examine you properly, and slow attentive movement then becomes a good companion to whatever they advise rather than a substitute for it.

Common Questions about quadratus lumborum pain (FAQ)

What does quadratus lumborum pain feel like?

People usually describe a deep, dull ache on one side of the low back, sitting between the top of the pelvis and the lowest rib. It often builds after standing, driving or a long stretch of sitting, can feel sharper when you side bend or twist, and sometimes eases once you lie down and let the muscle stop working.

What causes quadratus lumborum pain?

Most often it is sustained low level effort: standing with your weight parked on one leg, carrying a bag or a child on the same side, long drives, or sitting in a way that leaves one side of the trunk holding you up. Rather than one dramatic strain, it is usually hours of quiet work that the muscle never gets to put down.

How can I tell quadratus lumborum pain from a kidney problem?

You cannot tell reliably on your own, which is worth saying plainly. Kidney pain tends to sit a little higher and deeper, often does not change when you move or change position, and may come with fever, nausea or changes in urination. Movement related ache that varies with posture points more toward muscles and joints, but if you are unsure, or anything feels systemic, see a doctor.

Is quadratus lumborum pain the same as sciatica?

No. Sciatica describes pain that travels down the leg, often with tingling or numbness, and usually involves an irritated nerve. QL related ache tends to stay local, between rib and pelvis, though it can refer toward the hip or buttock. Pain running below the knee is a reason to have a professional take a look.

How often should I move, and how long until it eases?

Frequent and small beats rare and heroic. A few gentle breaks in every long stretch of sitting or standing, plus some slow, easy movement daily, gives the muscle regular chances to rest. Ache from overworked muscle often softens over days to a few weeks once the pattern changes; anything persisting beyond about six weeks is worth a professional opinion.

When should I get one sided low back pain checked?

Book an appointment if the pain is severe, keeps returning, spreads down a leg, follows an accident, or simply is not improving. And go urgently if it comes with fever, unexplained weight loss, night pain that will not settle, or any new change in bladder or bowel control. A clinician can rule out the sources you cannot assess from the inside.