SI Joint Stability: Why “Laxity” Advice Is Wrong (And What Actually Works)
The Truth About SI Joint Pain
Debunking the “laxity” myth and restoring real stability through sensorimotor control
If you’ve spent any time in the rehab corners of the internet, you’ve probably heard some version of this:
“Your SI joint ligaments are loose. Don’t cross your legs. Don’t do unilateral movements. Don’t move too much. Don’t move too little. Don’t breathe wrong. Don’t sneeze.”
Apparently the SI joint is a full-time drama queen… fragile, temperamental, and ready to throw itself onto the chaise lounge at the slightest hint of movement.
Except… it’s not.
Let’s talk about what the research actually says, why SI ligaments don’t behave the way people think they do, and how to restore stability without wrapping yourself in bubble wrap for 30 days.
What Research Actually Says About SI Joint Stability
The sacroiliac (SI) joints connect your spine to your pelvis and play a key role in how your body transfers load between your upper and lower body.
You have two SI joints—one on each side—but they function as a single system. These joints work together to transfer load between your spine and legs. While dysfunction often shows up as asymmetry, what matters most is how the system works as a whole.
Two key sources give us a much clearer picture:
1. Kiapour et al., 2020 (International Journal of Spine Surgery)
A review of 65 studies found that SI ligaments experience higher strain in women, especially under certain biomechanical loads, and that SIJ pain is usually a load-transfer problem, not a ligament-integrity problem.
2. Kusztor, 2024 (Doctoral Thesis)
Identifies pregnancy, posture, muscle imbalance, and systemic inflammatory conditions as contributors to SIJ dysfunction… not “crossing your legs wrong.”
So yes, SI ligaments can be stressed. But the reasons are not what Instagram says.
Three Documented Reasons SI Ligaments Become “Lax” (Spoiler: None Are Your Fault)
1. Pregnancy & Hormonal Changes
Relaxin and estrogen temporarily increase ligament compliance.
This is normal.
This is adaptive.
This is not a moral failing.
2. Altered Load Transfer (a.k.a. Sensorimotor Control Dysfunction)
This is the real issue.
When the deep stabilizers aren’t coordinating, the ligaments absorb load they were never meant to handle. This is the real culprit behind most SI pain.
It’s not about their STRENGTH… it’s about their timing. Sensorimotor control can be improved - and not by the bullshit reasons you find on Instagram.
3. Systemic Inflammatory Conditions
Certain medical conditions can affect ligament stiffness. This is a medical issue, not a “don’t cross your legs” issue.
Systemic inflammation is usually driven by the immune system reacting to something it perceives as a threat. Things like chronic stress, poor sleep, environmental irritants, or ongoing low-grade infections.
It can also be amplified by lifestyle factors such as ultra-processed foods, sedentary habits, or long-term mechanical stress that keeps the body in a protective state.
Now for the Fun Part: Why “Avoid All Unilateral Movement” Is Terrible Advice
Let’s be clear:
If avoiding unilateral movement fixed SI joint issues, every flamingo would be in chronic pain.
The SI joint is designed for:
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Load transfer
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Asymmetrical movement
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Walking (which is… unilateral)
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Stairs (also unilateral)
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Life - do I need to say it again? We’re bipedal. We live on two legs, thus, load transfer… it’s a life thing. You can’t get around it.
Avoiding movement doesn’t fix instability.
🔹 It deconditions stabilizers
🔹 It increases fear
🔹 It makes the system worse
What Actually Restores SI Joint Stability
This is where most advice falls apart.
In my twenties, I discovered Neuromuscular Therapy with legends in the field, Judy Delany and Leon Chaitow. Other legends in the field of NMT exist (Judy is still around) but John Sharkey, Aubrey Gowing, and other educators have massive courses to learn how to stabilize your SI Joint – without making you believe not moving is a great idea to help your SI Joint.
My understanding of sensorimotor control gave me the foundation to create the NeuroStrength framework which lives under the MELT Method brand. This self-care method is wildly misunderstood by people who think “strength” means “bigger muscles.”
NeuroStrength ≠ Muscle Size
NeuroStrength is about:
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reintegrating sensorimotor control
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restoring timing
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re-establishing force closure of the SI Joint
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then building strength on top of that
Strength without timing is compensation. Strengthen your body without boosting sensorimotor control – you become a stronger, more dysfunctional body over time. You get better at managing your problem without fixing it.
Timing without sensory clarity is chaos. NeuroStrength gives you both.
Why MELT + NeuroStrength Works for SIJ Issues
Movements like:
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Clam
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Side Leg Lift
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Side Hip Hero
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Knee Knockers
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Inner and Front Thigh Glide and Shear
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Side Hip Glide and Shear
…are not “dangerous unilateral movements.” They are the exact movements that retrain the deep stabilizers — when done correctly.
And “correctly” means:
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pelvis level
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ribs and pelvis in a 4-point square (curious to learn what this is, follow me on social and I’ll teach you what it is and why it’s critical in your MELT practice to regain SI Joint stability)
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no collapsing into the QL (Quadratus Lumborum)
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no gripping the rectus femoris
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no “fake stability” from global muscle movers
This is how you restore force closure, the real mechanism of SI stability.
Not by avoiding movement. Not by immobilizing the pelvis. Not by pretending your ligaments are made of wet tissue paper.
The Bottom Line
Let’s simplify this:
Your SI ligaments are not “loose” because of how you move.
They don’t heal by avoiding movement.
They don’t need protection—they need coordination.
What restores SI joint stability is:
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Nervous system regulation
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Fascial hydration
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Sensorimotor retraining
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Neuromuscular timing
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Gradual loading
Your SI Joint Isn’t Fragile — But Your Movement Patterns Might Be. Ready to Change That?
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If you’re tired of being told your pelvis should be wrapped in bubblewrap - that it must be protected at all costs, it’s time to step into a model that actually respects your biology. Your SI joint isn’t the problem — your system just needs better timing, clearer sensory input, and smarter load transfer.
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That’s what MELT and NeuroStrength were built for.
So here’s your invitation:
👉 Stop babying your SI joint. Start retraining it.
👉 Stop avoiding movement. Start restoring coordination.
👉 Stop fearing instability. Start building force closure from the inside out.
What To Do Next
If you’re ready to understand your body with more clarity, move with more confidence, and finally feel what real pelvic stability is supposed to feel like—start here:
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Explore guided sessions on MELT On Demand
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Learn how to apply NeuroStrength principles in your practice
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Begin restoring coordination before adding load
Your SI joint isn’t delicate. It’s adaptable. Let’s teach it how to thrive.
Want to Feel This in Your Body?
Before trying to “fix” your SI joint, start by understanding how your body is actually organizing.
In this guided session, Sue walks you through a gentle, fascia-focused practice designed to help you reconnect to your body’s natural rhythm—so you can move with more ease, stability, and flow.
This session is especially helpful if you’re navigating:
🦴 SI joint dysfunction
💆 Neck or lower back pain
🦵 Hamstring tightness or strain
🦿 Post-knee replacement recovery 👉 Watch: MELT for SI Joint, Back, Neck & Knee Relief
This is the first step before building strength or trying to correct movement patterns.
📌 Save this article to come back to when you need language — for yourself, a provider, or someone you love — that validates what your body has been saying all along.