Stretching is the first thing almost everyone tries for sacroiliac pain, and it is easy to see why: the muscles around an irritated SI joint feel tight, gripping, and desperate to be lengthened. A good stretch brings a wave of relief. The trouble is that the relief tends to fade within hours, and some of the most popular “SI joint stretches” — pigeon, butterfly, wide-leg forward folds — can leave the joint worse by evening. This is because the sacroiliac joint is usually a stability problem dressed up as a tightness problem. Stretching still has a place, and a valuable one. But it needs to be the right stretches, done gently, and paired with the strength work that makes the relief last. Here is how to do that.
Key takeaway: Gentle stretching eases the glutes, piriformis, hip flexors and lower back that grip around an irritated SI joint — knee-to-chest, figure-four, half-kneeling hip flexor stretch, child’s pose with knees together, and pelvic tilts are the safe ones. Avoid pigeon, butterfly, straddle and forced twists, which lever the joint open. Stretch for comfort, then stabilise with bridges and clams for lasting relief.
The best stretching exercises for the SI joint are gentle, symmetrical and target the muscles around the joint rather than the joint itself: single and double knee-to-chest, a supine figure-four stretch for the glutes and piriformis, a half-kneeling hip flexor stretch, child’s pose with the knees together, a gentle supine knee-rock, and slow pelvic tilts. Hold each for 20 to 30 seconds without forcing. Avoid pigeon, butterfly and wide-leg stretches, which lever an already loose joint open. Sophie Mercer, PMA-certified clinical Pilates instructor, designed an 8-week SI Joint Pain protocol of 32 exercises that pairs this gentle release with the stabilisation that makes relief last.
Does stretching help sacroiliac joint pain?
Yes — with a large and important caveat. When the SI joint is irritated, the muscles around it react by gripping: the gluteals, the piriformis and deep rotators, the hip flexors at the front, the quadratus lumborum and erector spinae in the lower back. That muscular grip is a real source of ache and stiffness, and gentle stretching genuinely eases it.
What stretching cannot do is stabilise the joint. In most people with recurring SI pain, the joint is moving slightly too much on one side, and the ligaments meant to hold it are irritated. Aggressive stretching, especially the hip-opening kind, adds to that laxity. So the rule is simple: stretch the muscles, not the joint. Keep the pelvis square, keep the range comfortable, and follow release with stability work — the logic laid out in my main guide to SI joint pain exercises.
The seven best stretches for the SI joint
Do these once or twice a day during a flare, and as a warm-up before strength work once it has settled. Breathe slowly throughout. Nothing here should produce sharp joint pain — a muscular stretch sensation is what you are after.
- Single knee-to-chest — lying on your back, draw one knee toward the chest holding behind the thigh, other foot flat. 20–30 seconds each side. Feel: the glute and lower back on the lifted side. Avoid: pulling on the knee itself or letting the pelvis twist.
- Double knee-to-chest — both knees drawn in, knees together, a small gentle rock side to side. 30 seconds. Symmetrical, and often the single most comforting position during a flare.
- Supine figure-four stretch — ankle crossed over the opposite knee, hands behind the supporting thigh, draw it in. 30 seconds each side. Feel: deep in the glute and piriformis. Avoid: letting the hip on the crossed side lift off the mat — that is the pelvis opening, which is what we do not want.
- Half-kneeling hip flexor stretch — one knee down on a cushion, the other foot forward. Tuck the tailbone slightly, shift forward an inch. 30 seconds each side. Feel: the front of the kneeling-side hip. Tight hip flexors tip the pelvis forward and load the SI joint; my guide on how to release tight hip flexors covers this in depth.
- Child’s pose with knees together — kneel, sit back toward the heels, arms forward, forehead down. 30–45 seconds. Key point: knees together, not wide. The wide version opens the pelvis; the narrow one lengthens the lower back safely.
- Supine knee-rock — knees bent, feet flat and wide, let both knees fall gently a few inches to one side, then the other. 10 slow rocks. Stay well short of the end of range.
- Slow pelvic tilts — knees bent, flatten the lower back to the mat then release to neutral. 10 reps. Technically a mobility exercise rather than a stretch, but it moves the joint gently through the middle of its range and eases the gripping around it.
Stretches that make SI joint pain worse
These are widely recommended online for “hip opening” and are exactly what an irritable SI joint does not need:
- Pigeon pose — extreme flexion and rotation of one hip levers the pelvis apart
- Butterfly and frog stretches — force the front of the pelvis open through the ligaments
- Wide straddle forward folds
- Deep lunges held for time, including low lunge and lizard
- Forced supine twists with the top knee pushed to the floor
- Self-manipulation — crossing the legs and wrenching the spine to get a “crack”
The full list of aggravators, with safer swaps for each, is in SI joint pain exercises to avoid. If your pain travels down the leg with pins and needles, the stretching advice changes — see sciatica exercises at home.
How can I loosen my SI joint at home?
Think “settle” rather than “loosen”. The seven stretches above, done gently, are the core of it. Add:
- Heat on the gluteal muscles for 10–15 minutes before stretching
- A tennis ball against the wall into the glute — mild pressure, 30 seconds per spot, never directly over the joint
- A short, easy walk on flat ground — rhythmic movement calms the gripping better than stillness
- A pillow between the knees in bed, and knees together when rolling over
What to leave out: any attempt to crack the joint yourself, and any stretch that requires the pelvis to open or twist to its limit. If the joint feels “stuck”, that stuckness is almost always muscular guarding, and it eases once the muscles feel supported — which brings us to strength.
Why stability makes stretching work
Here is the relationship in one sentence: stretching lowers the pain enough to let you strengthen, and strengthening stops the pain coming back so you no longer need to stretch as much. The gluteals, adductors, deep abdominals and pelvic floor compress the sacroiliac joint and hold it steady — when they are strong and quick to switch on, the surrounding muscles stop guarding, and the “tightness” you were stretching every day quietly goes away. Two exercises are enough to begin with, right after your stretches:
- Glute bridge — 2 x 10, pressing evenly through both feet, hold 2 seconds at the top
- Clam — 2 x 12 each side, pelvis stacked and still
The full progression from these to robust single-leg control is in exercises to strengthen the SI joint.
How the SI Joint Pain protocol helps
Sophie’s 8-Week SI Joint Pain Program is built on exactly this pairing — gentle, symmetrical release to calm the joint, then progressive stabilisation to protect it — across 32 exercises in a structured sequence. The stretches you have just read are its opening week; the remaining seven build the support that means you stop needing them every day.
This article is for informational purposes only and does not constitute medical advice. Low back and pelvic pain can have several causes; if your pain is severe, radiates down the leg, comes with numbness or weakness, or doesn’t improve, please consult a physiotherapist or doctor before continuing.