The function of a muscle spasm

Hey everyone,

So now that my SI joints are stable, it’s letting me observe different patterns within my body that I wasn’t able to see sooner.

When your SI joints are going out of alignment all the time, it’s hard to really see a pattern to it, or discern what your muscles might be doing.

But right now, my muscles are strong enough that they’re able to hold my SI joints in place as I do day-to-day activities (or go hiking!).

So now, what happens when I overdo it?

Now, thankfully, my SI joints don’t to move out of alignment the way they used to. (This is a combination of having enough muscle strength to stabilize them, and also knowing how to move my body in the ways that are the most functional).

What sometimes happens – which is totally normal and happens to people without SI joint issues too- is that I’ll end up getting muscle tightness and spasms, instead.

I used to find this pretty scary because sometimes, a muscle spasm can mimic the feeling of your SI joints being out of alignment. When this it first started happening, I’d freak out at first, until I realized no, my SI joints really are staying stable.

Now, I’ve learned to see muscle spasms differently.

With the way things are now, I can see how when a muscle tightens up, or even goes into spasm, that can actually be one way the body tries to create stability.

For example, I moved recently and spent much of the last two days unpacking things. I carried a bunch of stuff out to my car, to donate to charity. I was lifting and carrying things all day long.

By by the end of the day yesterday, I had a pretty noticeable line of tightness that stretched up from just over the side of my left SI joint, towards the spine. It didn’t really hurt or anything like that. But I noticed it.

This is the same area that used to get really tight when I would get an upslip, which is the term for when of the hip bones gets pulled upwards, relative to the spine.

What I learned about upslips is that they are usually caused when a muscle called the quadratus lumborum gets tight and pulls that hip bone upwards.

The Quadratus Lumborum muscle highlighted in dark red. Photo credit Uwe Gille

And, wouldn’t you know, that’s exactly the same area where I felt things start to get tight last night.

The difference now is that, last night, I had enough strength in all of the other muscles around the QL, so when it spasmed, it wasn’t acting all by itself to pull the hip bone out of place. Now, it had other muscles as well, acting also to keep that hip bone in one place.

And last night, I saw that quadratus lumborum spasm differently.

When I didn’t have enough muscle strength to hold my SI joints in place, I couldn’t really see it because I would instantly get an upslip, which would really destroy my ability to analyze anything else that was going on.

But last night, I was able to feel some warmth, or almost kindness, towards my QL spasm.

Because while all of my other muscles were tired, from lifting and carrying things for two days, the QL was still going. And that spasm, in some senses, was actually, one of the things that helped to give some stiffness to my lower back area, now that all of my other supporting muscles were tired out.

The role of the QL, and why it goes into spasm, is something I first learned about through some really interesting conversations with my mentors at Muldowney Physical Therapy and Inspire Motion PT.

We are taught to think of muscle spasms as bad. Of course, in some ways, that makes total sense! They hurt!

However, if we look at why muscle spasms really happen, they can actually be a way for our body to create stability when all of the other options had failed.

Last night, all of the other muscles I’d been building up around my SI joints were finally maxxed out. My nervous system didn’t like this, as it sensed that things were starting to feel weaker. So it resorted to Plan B– calling on the one muscle that wasn’t quite as tired, and sending it into spasm.

That spasm creates a brace, in a sense. It’s an area of stiffness that gives other muscles something firm to attach to, when they may be struggling to do their own jobs.

When I was really weak, this protective mechanism would then backfire, as it would pull me into an upslip which I then needed my PT to correct.

But now I can see how, in its own right, the QL was actually just trying to help.

Published by Christy Collins

Hi, I'm Christy! I'm a health coach who helps people overcome SI joint dysfunction and chronic pain.

6 thoughts on “The function of a muscle spasm

  1. How long did it take you to get better? I am going on year 4 each is a little closer but I would like to speed it up thou.
    Randall Lee Weed Jr


  2. Yes Christy this leads me to a question that has plagued me for a while. How do we know when we have the right BALANCE of muscle tightness/strength vs. too tight and therefore might pull the SI joint out of alignment? I am told to stretch the psoas and piriformus because if they are too tight they could pull SI out. Other muscles need to be strenghtened to provide support but if for instance, the QL is too tight (in relation to other muscles) then THAT can pull you into an upslip. It does get pretty confusing as to which muscles to strengthen and to what degree and how to know if balanced against other muscles. Does my quandry make sense?


    1. Yes. In some senses there are a few concrete things you can know. For example, everything I’ve learned about an upslip states that the QL is *always* involved. In terms of other patterns of imbalance, you could look at which ways you keep going out of alignment. For example, if you continually have an anterior rotation on one side, you can generally assume that the muscles in the front (the hip flexors) are tight, and the muscles in the back (hip extensors) are weaker. A PT can also do some strength testing on you to give you a general sense of how your muscles are balanced (or not so balanced).

      I hope this helps!


      1. Finally I have found someone that also has linked SI disfunction with spasm of the QL! I have been dealing with these two issues since a slip on the snow over 6 years ago. I have been attributing the spasm to the SI joint disfunction but I see that you are labeling the spasm as the cause of the joint movement. It’s a new idea for me.


        1. Glad this was helpful! I think it’s much easier for the QL to be able to pull the hip bone upwards after an injury, once the ligaments have been sprained. So your fall could have caused the initial ligament injury and the muscle spasm… but now it’s a pattern that’s become chronic (but can definitely still be corrected!).


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