If you are hypermobile — whether that is a lifelong flexibility you have always had, a formal diagnosis of hypermobility spectrum disorder or hypermobile Ehlers-Danlos syndrome, or simply the temporary laxity of pregnancy — the sacroiliac joint is one of the places it tends to show up first. This joint relies on ligaments more than almost any other in the body, and when those ligaments are lax, the pelvis moves in ways it was never designed to. The result is a deep, shifting, one-sided ache that stretching makes worse and cracking makes worse still. I want to be reassuring here: hypermobile SI joints respond extremely well to the right exercise. But the right exercise is very different from what flexible people are usually drawn to. This is a guide to stability for a pelvis that has too much movement.
Key takeaway: A hypermobile SI joint needs muscular stability to replace what its lax ligaments cannot provide. Strengthen the gluteals, adductors, deep abdominals, multifidus and pelvic floor with slow, symmetrical, mid-range exercises — bridges, clams, adductor squeezes, dead bugs, bird dogs, side planks — and progress to single-leg control gradually. Avoid stretching the joint, end-range hip openers and cracking, which all increase laxity.
The best exercises for a hypermobile SI joint build muscular compression around the pelvis to replace the stability lax ligaments cannot provide: glute bridges, clams, adductor squeezes with a ball between the knees, dead bugs, bird dogs, side planks from the knees, and pelvic floor and deep abdominal activation with the breath. Every exercise stays well inside the available range, moves slowly, and loads both sides evenly before any single-leg work is introduced. Stretching, hip openers and self-cracking should be avoided. Sophie Mercer, PMA-certified clinical Pilates instructor, designed an 8-week SI Joint Pain protocol of 32 exercises whose stabilisation-first approach suits a hypermobile sacroiliac joint particularly well.
What does a hypermobile SI joint feel like?
The picture is distinctive once you know it:
- A deep, one-sided ache low in the back, just beside the sacrum, often described as being “in the hip” or “in the bum”
- A sense of the pelvis being unstable, shifting, or clunking — particularly on one leg, rolling in bed, getting out of a car, or stepping off a kerb
- Pain that is worse with prolonged standing and walking and better lying down, the reverse of a stiff joint
- A near-constant urge to stretch or crack it, which brings brief relief and a worse ache afterward
- Gluteal and lower back muscles that feel permanently tight — because they are gripping to compensate for the ligaments
- Frequently, a history of other loose joints: shoulders that sublux, ankles that roll, knees or elbows that hyperextend
If you also have pins and needles or numbness below the knee, weakness in the foot, or any change in bladder or bowel control, that is not an SI joint pattern and needs medical assessment before you exercise.
Can hypermobility cause sacroiliac pain?
Yes, and the mechanism is worth understanding because it dictates the whole approach. The sacroiliac joint is stabilised in two ways: the interlocking shape of its surfaces (form closure), and compression from the ligaments and muscles around it (force closure). In most people the ligaments do a great deal of that work silently. In hypermobility, the collagen in those ligaments is more extensible, so the passive support is reduced and the joint moves more than it should. The surrounding tissue becomes irritated, the muscles grip, and the cycle of ache-stretch-relief-ache begins.
Pregnancy produces the same picture temporarily through the hormone relaxin, which is why the advice in exercises for SI joint pain in pregnancy overlaps heavily with this one. Either way, the ligaments cannot be tightened by exercise. What can be built is the muscular half of force closure — and in a hypermobile body it needs to be built deliberately, because it has to do more of the job.
How to fix a hypermobile SI joint: the principles
Before the exercises, four rules that apply to every one of them:
- Stay in the middle of the range. Hypermobile joints have more range than they can control. Train the zone you can control, not the zone you can reach.
- Slow down. Momentum hides weakness. A three-second lift and three-second lower reveals it.
- Symmetry first, single-leg last. Both sides of the pelvis must load evenly for several weeks before one side works alone.
- Muscular effort, never joint pain. A working sensation in the glute or inner thigh is the goal. A deep, familiar ache at the joint means the exercise is too far or too much.
The stabilisation routine for a hypermobile SI joint
Do this five to six days a week. Two sets of each in the first three weeks, three sets from week four. Total time is around fifteen minutes.
- Pelvic floor and deep abdominal activation — lying with knees bent, exhale and gently lift the pelvic floor while drawing the lower belly in about 30 per cent. Inhale and release. 8 breaths. This is the inner cylinder everything else attaches to. Hypermobile bodies often have a pelvic floor that is either under-active or over-gripping; my guide to pelvic floor exercises during pregnancy explains the connection with breath in a way that applies to everyone.
- Glute bridge with adductor squeeze — a ball or cushion between the knees, squeeze gently as you lift. 10 reps with a 3-second hold. Feel: the back of the hips and the inner thighs together. Avoid: lifting so high the ribs flare.
- Clam — side-lying, knees bent, heels together, pelvis stacked. Open the top knee only as far as the pelvis stays still. 12 each side.
- Side-lying leg lift — top leg straight and slightly behind the body, heel leading. 10 each side. Avoid: letting the top hip roll backward — hypermobile hips do this readily.
- Dead bug — arms up, knees over hips, lower opposite arm and leg only as far as the low back stays gently down. 8 each side.
- Bird dog with a short reach — four-point kneeling, slide the leg back rather than lift it high, reach the opposite arm forward. 3-second hold. 6 each side. Key: a glass of water balanced on the pelvis would not spill.
- Side plank from the knees — hips stacked, lift and hold 15 seconds. 3 holds each side. Lateral control is what stops the pelvis shifting on one leg.
- Prone glute set — face down, squeeze the buttocks together for 5 seconds without arching. 10 reps. A simple way to make sure the glutes actually fire.
From week six, if all of the above is controlled and pain-free, introduce bridge with march, then a single-leg bridge and a low step-up, exactly as laid out in exercises to strengthen the SI joint.
What exercises should people with hypermobility avoid?
Flexible people are drawn to flexibility work, and it is the one thing a hypermobile SI joint does not need. Approach these with real caution:
- End-range stretching of any kind, and hip openers in particular — pigeon, butterfly, frog, straddle, splits
- Deep lunges and long-held warrior poses
- Ballistic or bouncing movement, and high-impact running and jumping during a flare
- Heavy loaded rotation — Russian twists, woodchops
- Self-manipulation — the crossing-the-legs-and-twisting “crack” that hypermobile people are so good at
- Very long holds at the limit of range, including in yoga
The broader list of aggravators, with safer alternatives, is in SI joint pain exercises to avoid. A useful mental test for any new exercise: does this ask the joint to go somewhere, or to stay somewhere? Hypermobile joints need the second.
Beyond exercise
A sacroiliac support belt can be genuinely helpful in the early weeks for people with marked laxity — it supplies external compression while the muscles catch up, and should be phased out as they do. Proprioception matters too: hypermobile people often have a reduced sense of where the pelvis is, so slow exercises with attention to what you feel are doing double duty. If you have a hypermobility diagnosis, a physiotherapist familiar with hypermobility spectrum disorder or hEDS is worth finding, as pacing and fatigue management are part of the picture. And a pelvis is only as stable as its base — if pelvic floor weakness or urgency is part of your story, the 6-Week Pelvic Floor Strengthening Program addresses that foundation directly with 26 exercises.
How the SI Joint Pain protocol helps
Sophie’s 8-Week SI Joint Pain Program is stabilisation-first by design — 32 exercises across eight weeks that build gluteal, adductor and deep core support around the pelvis before asking it to handle any single-leg load. For a hypermobile sacroiliac joint that is exactly the right order, and the week-by-week structure removes the temptation to progress too fast or drift back toward the stretches that feel good and make things worse.
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 — especially if you have a diagnosed connective tissue disorder.