Dean Somerset on SI joint dysfunctions

Dean Somerset is a really interesting exercise physiologist/personal trainer based out of Canada.  He has a website where he offers a lot of cool resources on the body, training, and, of course, the SI joint.

He has two articles:

SI joint dysfunction

Stuff You Should Read: SI Joint Edition

Now, the thing about the SI joint is that its shape can vary so widely between people… and so can the range of injuries, as well as what works to help people get better.  So, some of the things Dean mentions in his article definitely did not work for me.

However, he has a great explanation of the joint itself, and how injuries to it can generally work, as well as advice for what worked for him personally as well as for his clients with SIJD.


On my blog, I share anything that I think is well-researched and scientifically valid– even if it doesn’t line up completely with my personal experience– so I definitely think Dean’s perspective is worth reading.

In my experience, when you’re looking for someone to help you with an injury or chronic pain– be it a physical therapist, doctor, or in this case, personal trainer– you want someone with a solid general understanding, as well as an open enough mind to see where you as an individual might require a different course of action from what he or she would generally recommend.  We are all different; we all have our own individual quirks, and so do our bodies.

So, would I consider consulting someone like Dean for help with an SI joint problem, even though he recommends a few things which I know would never not work for me (like compression shorts and heel lifts)?  Absolutely… it’s still clear that he knows what he’s talking about, and understands how complex the body can be.

Generally speaking, you are never going to find someone who’s going to be able to wave their magic wand and fix your problems instantly… you want someone who can work with you collaboratively and provide you with new information, and basically you can bounce information off of each other and try new things until you figure out a path that works.


So, with that being said: as always when I find something good, I wanted to take a few notes on what Dean says about the SIJ.

(Some of these notes are probably more for me than for you– I’m trying to remember where I learned certain facts for when I someday publish my best-selling e-book!  I also try to take a note of instances where I think someone used language really well in order to explain something.  So I hope you find some of these snippets interesting).


“Not quite the lumbar spine, so it doesn’t quite follow the same movement parameters as the low back, and it’s not quite in the pelvis so it doesn’t follow the same movement parameters of the hip. This means that it’s kind of caught in the middle, and often overlooked as a means of causing some form of low back pain. Conservative estimates put the occurrence of SI joint pain at around 10-27% of all back pain sufferers, which means there are millions of people walking around with this little bugger giving them grief.”

“The SI joint is made of 2 main components: The sacrum, or base of the spine, sits in the middle of the structure and looks like a key fitting into a lock. The bony architecture makes it fit pretty tightly with the ridges of the illium, which means the joint has a great design to bear loads, specifically through axial loading.”  (This means it is designed to bear weight/transfer forces that travel through the joint vertically/straight up and down).  

“The joint is designed to rotate in order to allow movement. The sacral rotation occurs along an oblique axis, meaning it’s not straight up and down or side to side, but on an angle. This means that if you’re walking forward with your left foot, it causes a rotation to push your torso forward and swing your right arm to create some rotational momentum to distribute the forces of the pelvis.”  (would totally love a citation for this, because I still read articles by clinicians saying the SI joint doesn’t serve much of a purpose!).

Although the joint is great at distributing vertical forces– that is what it’s designed for– it is anatomically vulnerable to any kind of forces which would push the sacrum and the ilium in different directions (this is what is known as shearing forces). 

This is generally how most SIJ joint injuries occur– an even force is applied to the body and it pushes the bony structures (the sacrum and the ilium) away from each other, spraining the ligaments.  “While the SI joint is great at distributing forces from axial loading, it sucks at distributing shear forces, which can be applied by hitting one hip against a solid surface, applying a torque to the pelvis or low back, or creating uneven loading between the two legs.”

Dean even has a great picture of an MRI showing a dramatic SIJD injury– normally these injuries are too subtle to show up in imaging.

He explains that when he had an SIJ injury, he even noticed it getting worse when he tried to do things like an overhead dumbell raise (this is probably not something most of my blog readers need to worry about, but basically, he was saying that once he injured it, he experienced pain doing things that the joint was designed to do, that wouldn’t have caused pain before).

He gets how bad it can be:

“Basic things that can cause some sot of shear in the SI joint, further complicating how you can help and reduce symptoms, includes sitting, standing, laying down, sneezing, coughing, walking, wearing red, eating wheat, and being born a virgo. All kidding aside, SI joint issues can be made worse in pretty much any sustained position, and can be aggravated pretty quickly with sudden movements.”

“Because the pelvis is responsible for distributing forces from the legs to the torso and vice versa, any alteration in the SI joint can cause a world of hurt. When walking, the weight shifts from one foot to the other, and the SI joint has to rotate to compensate and propel the body forward, which also places a shear force on the spine.”

Basically, even though the SIJ is only supposed to move a few millimeters, when those few millimeters are restricted, it can throw off the entire walking process.


After this, there is more technical stuff about training which I won’t get into in as much detail (mostly because I don’t want to plagiarize his entire article!).

But I appreciated how he pointed out that there can be generic core strength training programs are a terrible idea for the SI joint– most core training programs are designed for people with stable pelvises, and if your SIJ is already compromised, you will likely make it worse if you follow generic strength training advice.

I’m sure this is something most of my readers already know, but still– it’s so nice to have someone else vindicate what we go through.

I’m going to end this post here, but if you have any questions on this article (or anything else) you can always email me! 

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