SIJ dysfunction symptoms: what is your pelvis trying to tell you?

Reviewed by the Biokinetics clinical team

Key insights

• SIJ pain is typically one-sided and sits below the beltline, and it flares with transitions: rolling in bed, getting out of the car, stairs and single-leg tasks.
• A pelvis that “feels out of place” usually reflects altered load transfer and muscle guarding, not a bone that has slipped and needs pushing back.
• Generic SIJ dysfunction exercises help some presentations and aggravate others, which is why assessment comes before any program.
• SIJ symptoms often overlap with hypermobility, and can first appear during rehab after spinal or back surgery.
• An initial assessment runs 60–90 minutes; no GP referral is needed, and HICAPS rebates are available where your fund supports it.

Few joints cause as much confusion as the two at the back of your pelvis. The sacroiliac joints (SIJ) sit where the base of the spine meets the pelvic bones, and their job is load transfer: every step, lift and change of direction passes force between your upper body and your legs through them. When that system stops coping, the result is pain that moves, mimics other problems, and rarely shows up neatly on a scan, which is exactly why so many people spend months chasing the wrong diagnosis.

What does SIJ dysfunction actually feel like?

No two presentations are identical, but the same patterns come up again and again:

• Pain low and to one side. Typically below the beltline, over one buttock or the back of the pelvis, rather than across the middle of the lower back.
• Pain with transitions. Standing up from sitting, rolling or turning in bed, getting in and out of the car, and going up stairs are common aggravators.
• Pain with single-leg load. Walking, standing on one leg to dress, or stepping up can reproduce the pain, because these tasks ask one side of the pelvis to carry the load alone.
• A feeling of instability. Many people describe the pelvis as unreliable under load, as though it might give way, catch or shift.
• Referred pain. Pain can spread into the groin, hip or the back of the thigh, one reason SIJ problems are so often mistaken for hip or lumbar spine issues.

Why does my pelvis feel “out of place”?

It is one of the most common phrases in our assessment rooms, along with “twisted pelvis”, and the sensation deserves to be taken seriously. It usually reflects altered load transfer, muscle guarding and sensitised tissue around the joint. What it generally does not mean is that a bone has physically moved out of position and needs to be pushed back in: the sacroiliac joints are bound by some of the strongest ligaments in the body. That distinction changes the goal of treatment. Rather than repeatedly “putting the pelvis back”, rehabilitation restores the pelvis’s ability to handle load, so the sensation of shifting and unreliability settles.

Is it my SIJ, my hip, or my back?

The SIJ sits between two much more famous neighbours, the lumbar spine and the hip, and can mimic both. Pain spreading down the thigh gets labelled sciatica; groin pain gets labelled a hip problem. Because the joint is a load-transfer system rather than a single sore spot, useful assessment looks at how the whole chain handles force: gait, single-leg control, hip strength and lumbo-pelvic coordination, not just where it hurts.

Should I just do SIJ dysfunction exercises from the internet?

Search results are full of generic SIJ dysfunction exercises, and this is where many people get stuck: an exercise that helps one presentation can aggravate another, particularly where hypermobility or pregnancy-related pelvic changes are involved. That is why we do not publish a one-size-fits-all exercise list. The sequence that works is assessment first, then a staged program built around how your pelvis is actually failing under load: stabilise, then load, then integrate back into walking, work, parenting and training.

When is it time to get assessed?

Book an assessment if pelvic or one-sided lower back pain has persisted for more than a few weeks, keeps returning, interferes with walking, stairs, sleep or lifting, or has not responded to previous treatment. Pregnancy-related and postpartum pelvic pain also warrants assessment rather than waiting for it to pass. An initial Biokinetics assessment runs 60–90 minutes and looks for the mechanism behind the symptoms, not just the painful site.

Common questions

Is there a single test for SIJ dysfunction?

No. Clinicians use a cluster of load and provocation tests, read alongside gait, single-leg control and hip strength, because the SIJ rarely fails in isolation. Imaging is used selectively; scan findings alone often do not explain SIJ symptoms.

Could hypermobility be part of the picture?

Often, yes. Generalised joint hypermobility is commonly screened with the Beighton score test, a nine-point scale covering the little fingers, thumbs, elbows, knees and spine. An online Beighton score calculator can give you a quick indication, but a score is a screening starting point, not a diagnosis, and it says nothing about how your pelvis handles load. Bring your result to your assessment and we will put it in context.

Can hypermobility cause problems beyond the pelvis?

Yes, it can involve multiple regions at once, from the SIJ to the neck. CCI symptoms (craniocervical instability) can include neck pain, headaches and a sense of instability at the top of the neck; there is no single CCI test, so assessment combines clinical examination with specialist input and imaging where indicated.

Does POTS come into this?

POTS (postural orthostatic tachycardia syndrome) commonly travels alongside hypermobility. It is diagnosed and managed medically; where it forms part of your picture, we coordinate with your medical team and pace rehabilitation around it.

Can SIJ symptoms appear during rehab after spinal fusion surgery?

They can. After a fusion, the joints above and below the fused segment, including the SIJ, are asked to take on more of the load, and some people first notice pelvic symptoms during this period. It is a reason to have your rehabilitation reviewed, not a sign that the surgery has failed.

How long is recovery after back surgery?

There is no universal recovery timeline. Progression follows your surgeon’s guidance and how your function responds, and a good plan states its own milestones and decision points rather than borrowing someone else’s timeframe.

What does physio after back surgery involve?

It is staged: early protection and walking progression, then control and foundational strength, then capacity and return to full activity.