Pain in the Butt, Sacroiliac Pain as Tendinopathy?

I recently finished the 3rd edition Stuart McGill’s “Low Back Disorders.” I’ve followed his work since reading edition 2 and bulk of my back pain treatments are based on, or consistent with it and his more recent research. For those who don’t know, McGill is a Professor of Spine Biomechanics at the University of Waterloo in Canada, for which he focuses entirely on low back pain. Subsequently, more of my back pain blogs reference his research than any other source.

I was wondering what was new in the 3rd and if it were worth buying and reading through. In short, it was both. The basic gist of his treatment hasn’t changed (but there was a lot of additional detail and ideas). Said gist to eliminate back pain is to lessen the injury causing stress from daily activities, while working on exercises (to make the person fit enough) and motor skills (to make them coordinated enough) to better tolerate the rigors of life without reinjury. I 100% endorse those principles.

All the above is all filler, and sets up what I wanted to get too, which was one of the more interesting sections new to the 3rd edition of Low Back Disorders which I have never seen mentioned anywhere else. The observation appears to be anecdotal, but it’s Stuart McGill’s anecdote, which means something, and I also happen to think this observation is often correct. On page 142 he talks about sacroiliac pain (literally pain in the butt) with the following being a few of his quotes:

“Boguk and colleagues (1996) proved that some low back pain is from the sacroiliac joint itself. The following discussion offers other considerations.”

“One possibility worth considering is that the high muscular forces may damage the bony attachments of the corresponding muscle tendons. Such damage has perhaps been wrongfully attributed to alternate mechanisms.”

“It is known that a large portion of the extensor musculature obtains its origin in the SI and posterior superior iliac spine (PSIS) region (Bogduk, 1980). The area of tendon-periosteum attachment area for connective tissue places the connective tissue at high risk of sustaining microfailure, resulting in pain (McGill, 1987).”

“This mechanical explanation may account for local tenderness on palpation associated with many SI syndrome cases.”

My comments:

McGill didn’t use the the word tendinitis, or more accurately the words tendinosis and tendinopathy. However, when he uses the words “microfailure” of the “tendon-periosteum attachment area” of the spine “extensor musculature” at it’s point of “origin in the SI and posterior superior iliac spine” it sure sounds like he’s describing tendinosis, with the resulting pain being tendinopathy of the spine extensor tendons. So far there is zero research describing tendinopathy in this region, but there is no reason I can think of why it couldn’t be. Also thinking about it, gluteus maximus also attaches right there, along the SI joint region as well, so it’s tendinous region could be involved as well, while all this time it’s been blamed on the SI joint or the piriformis muscle (which I have never seen get better stretches either).

The SI joint as a source of motion or pain has long been a source of debate in physical therapy, with studies and arguments pointing for and against for decades. I’ve never been passionately drawn to either side of the argument. However, I have stress tested a lot of SI joints and rarely do I find those tests positive for pain, and if the tests are painful, I think it’s still hard to tell if the SI joint itself is the source. Also I’m skeptical treatments directed at the SI joint reliably decrease that pain. I wouldn’t go so far as to say they never do, but just not often enough to make such treatments worth routinely doing. I’ll add that sometimes when there is debate and no clear answer, it’s because there’s something amiss and it wouldn’t be the first time that tendinopathy reared it’s head in an unbenounced place. Another reason I don’t usually give SI pain special attention is my SI pain patients generally get all the way better with my somewhat standard low back treatment protocol. So thinking about what McGill wrote above, how I treat back pain and how I treat tendinopathy, I have a idea as to the reason why.

That reason is that my treatment protocol for back pain, bares more than a passing resemblance to my treatment for tendinopathy. In short, I’m basically treating for both already. Besides biomechanical and postural counseling, teaching the person with back pain how to better maintain a neutral spine during the day, I have them work to increase basically total body strength and endurance emphasising spine stability and hip mobility, with an exercise program that is generally 3 sets of 15 reps, with easy-medium-hard resistance levels. I have them progressing the weights on the next visit if the person is able to get all three sets without pain and with good technique on the prior treatment. That’s almost identical to how I treat tendinopathy, with an example being tennis elbow (aka shooter’s elbow described here) or coracoidopathy described here. In both cases I try to increase strength and endurance of all the muscles stabilizing the affected area, followed by focused strengthening of the affected muscle/tendon with 3 sets of 15 reps ( also easy-medium-hard resistance levels).

So if a person has tendinopathy of their spine extensor muscles (or gluteus maximus) where they attach on or near the SI joint, that would explain why my back pain type sets and reps, has hitherto resolved those symptoms without me even considering tendinopathy of the area being a possible cause.

Some considerations I’ll be thinking about going forward is that with back pain I endeavor to never have my patients train through pain, however with tendinopathy I try to use a resistance level that causes some pain, noting that pain almost always stays the same/or lessens in spite of increasing weights from set to set. With back pain, for which I might suspect a bulged (nearly bulged) or herniated disc, training through pain usually results in a worsening the person’s condition from one set to the next. Also with tendinopathy I notice people get better faster if they do the exercises every day rather than three times a week and my observation does have empirical support.

So if there is SI region tendinopathy I think it’s probably better to error on the site of caution and not increase resistance levels if there is any pain, which thus far seems to be working well enough. However, if the person has SI region pain, no lumbar or radicular symptoms (leg pain and tingling) I might consider a slightly more aggressive (slightly more specific tendinopathy) type approach. However, I imagine there is a lot of overlap between both conditions, such that if someone has spine extensor tendinopathy, they very likely have some spine disc or ligament issues as well even if they don’t have pain yet, so daily pain free resistance exercise of the spine and hip extensor muscles (with the spine kept neutral throughout) is maybe the safest and best approach.

For the record, I suspect upper back pain and tenderness where the levator scapula muscle attaches to the scapula is sometimes and maybe often be tendinopathy too. Which seems to resolve with my basic neck pain protocol, which like my back pain treatments includes (your guessed it) progressive resistance training with 3 sets of 15 reps (easy-medium-hard).

Thanks for reading my blog. If you have any questions or comments (even hostile ones) please don’t hesitate to ask/share. If you’re reading one of my older blogs, perhaps unrelated to neck or back pain, and it helps you, please remember Spinal Flow Yoga for you or someone you know in the future.

Chad Reilly is a Physical Therapist obtaining his Master’s in Physical Therapy from Northern Arizona University. He graduated Summa Cum Laude with a B.S. Exercise Science also from NAU. He is a Certified Strength and Conditioning Specialist, and holds a USA Weightlifting Club Coach Certification as well as a NASM Personal Training Certificate. Chad completed Yoga Teacher Training at Sampoorna Yoga in Goa, India.

15 thoughts on “Pain in the Butt, Sacroiliac Pain as Tendinopathy?”

  1. Have you had a chance to read McGill’s “Back Mechanic”? I find myself using this book and “Ultimate Back Fitness and Performance” a little more than his “Low Back Disorders”. I was a little disappointed in his DVD’s, the one I have is a glorified video of some of his continuing education courses. All his work is worthwhile. Too bad he is retiring from academics.

    • Hi Ron,

      Yeah I actually just finished Back Mechanic a few weeks ago. I really liked how McGill worded some concepts in it, and with it I think I can better explain some ideas to my patients. Plus, it was a good review of what he thinks is most important. I think it’s definitely more accessible than Low Back Disorders for laymen, but that most people aren’t going to read something that detailed either. And yeah, as much as I agree with McGill’s treatment principles, I do tend to incorporate them into more fitness type exercises like in Ultimate Back Fitness or rather some of my favorite weightlifting/bodybuilding exercises, minus the one’s bad for the back, more so than what’s in Low Back Disorders. Heck, now that I use EMS for abdominal strengthening, I don’t use “the big three” that much anymore. I still think the big three are great for a HEP when patients don’t have any equipment, though I almost always use the “modified side bridge” instead of the normal one.

      My above blog was getting long, but I was thinking that if you had SI region tendinopathy that you would need higher intensity exercise to remodel those tendons than a bird dog would provide, so standing cable rows, squats, RDLs, etc. with weights would maybe work better. I’m thinking the same thing for greater trochanteric pain syndrome and gluteal tendinopathy, where more aggressive progressive resistance exercise (with the spine still locked in neutral) would better remodel the tendinosis region than big three and clam shell type exercises can deliver. Maybe full on side bridges would, but I notice they can be hard on the shoulders of my patients who often aren’t as fit as the McGill subjects in his books.

      As for the DVDs, I guess I liked them all, maybe not the golf one so much, but I agree I get more out of the books. I hadn’t heard about him retiring, but I suppose he’s earned it. I’ve been following some of Jack Callaghan’s stuff regarding standing low back pain in particular. I think they worked out of the same lab at the University of Waterloo. Definitely let me know if you come across anyone else worth reading. I’m on a roll for back pain books, having recently finished Back Pain Revolution and got almost nothing out of it, except I think for a thorough understanding of the holes in the biopsychosocial model. I’ve been meaning to do a blog on that one as well.

  2. hi chad,
    it was because of you that i found out about stu mcgill over a month ago. i had been off work for over 2 months back in late february looking at mckenzie physio videos when i decided to see if anyone had anything critical to say about it which led me to your blog where you referenced stu mcgill. i live close to waterloo and my nephew’s wife teaches pharmacy at u of w. i had never heard of the guy and not one of the physios i had ever gone too mentioned him or his work or followed his recovery path. i spent days watching a lot of his videos and listening to other physios interviewing him on their blogs and then ended up buying back mechanic. i emailed him asking whether he could recommend someone he trained or knew that i could see for an assessment.lo and behold i got a reply 30 minutes later from mcgill himself. he’s retired and living up in what we call cottage country. he still examines and treats individuals for $600 cdn dollars a month if anyone is curious but did recommend a former phd student of his who is now a chiropractor.

    so thanks a bunch there chad. I wish you practiced around here. i’ve watched a few of your videos. keep up the good work and say hello to walter white for me 😉

    • Hi Richard,

      That’s a cool story! It’s interesting to me that none of the local physios to you had heard of him. From what I can tell here in the USA, not that many physical therapists are aware of or follow his research either. I’m glad you were able to find help nearby, it seems a lot of people cant.

    • Hi again Ron,

      A number of people were telling me about that article and I have numerous and mixed feelings. It’s timely because my project for this year is to come up with an ideal yoga routine for low back and neck pain. The aim being a sequence of exercise that maintains a neutral spine throughout, improves spine stability, hip mobility, teaches good motor control, etc. Basically a yoga sequence that incorporates all the good that McGill talks about, including (as best as I can) my strength training stuff, while avoiding all the spine flexion/extension and twisting, which admittedly rules out a lot of traditional yoga asanas. Also I still want to preserve various and positive mindfulness aspects of yoga, which seems to be holding up well in the research. In doing so I’ve taken a fair share of yoga classes, read most of the yoga and back pain research, as well as books. So it’s good timing that this paper came out now.

      It took us a while to find the above paper, but here it is. They don’t list any of the details about either the yoga program or the physical therapy routine in that paper but here is the teacher training manual that describes the yoga routine reasonably well. I had to go back to their 2014 protocol description to see the details regarding the physical therapy program. Basically it sounded like McKenzie stretches into either flexion or extension (and we all know what I think of McKenzie method) plus some very low intensity and extremely long duration lumbar stabilization exercises. Like 30 reps with 8 second holds. It’s hard for me to imagine anything more boring. That was followed by 30 minutes of aerobic exercise, and no modalities. I couldn’t see that they did anything substantial to strengthen hips nor anything to teach good spine/hip motor control in real life situations. The researchers referred to the pain as non-specific, so overall I got the impression they didn’t have any exposure to McGill’s research. So in short I thought it was a substandard (though fairly standard) yoga routine, followed by a substandard physical therapy routine (not that I think most PT protocols are worth bragging about). So I’m not surprised the results were similar. What they fail to mention is the world news outlets and all the press this paper got was that neither the yoga nor the physical therapy program improved pain very much over that of the education group, who just got a book to read. The book itself being a copyright 1999 hodgepodge of what I think was some good and some bad advice. It definitely wasn’t “Back Mechanic.”

      What didn’t make the news was the fact that neither the yoga nor the physical therapy program worked very well. Outcomes for both were better than the education only group, but outcomes weren’t that much better. For example at week 12 the yoga and physical therapy pain scores dropped from 7ish only to a 5ish, while the control group decreased to a 7/10 to a 6, which would make me wonder if any of the routines were worth the effort or if either the yoga or physical therapy programs were better than placebo, and were perhaps just a higher, or more theatrical a placebo.

      I have a lot more comments that I’m working on now about the best way to share them, such that they’ll be well received. I’m thinking that’s the tricky part.

  3. Hi, Chad,
    I really hope this comment reaches you, because I really need help. I’m 35. This all happened a year ago, when I was 34. At the time, I was completely healthy, walked several miles a day, and enjoyed life tremendously. All that is different now.

    Last September I tore the TA muscle partially from the pubic bone. At the time, I didn’t know that was what had happened, so I underwent a battery of ridiculous and painful tests & procedures, including steroid shots to the abdomen. Following a colonoscopy (that is how clueless medicine is with regard to torn abdominal muscles in non-athletes), a nurse moved me improperly while I was still groggy from anesthesia and I fell like a tree on my butt/low back. Hard, from my full height of 6 feet (I’m female).

    This fall might not sound so bad, but it tore both hip labrums; made both hips excruciatingly painful whereas before they’d never pained me at all, ever; triggered chronic SIJ dysfunction; caused L4 & L5 to both bulge and tear (the annular tears are described as “mild,” but they are on the outside where all the disc nerves are); severely bruised (possibly fractured, never did find out) my coccyx; and made the original abdominal injury, which was actually quite mild, worse. I cannot describe to you the agony I went through for the next three months. I remember at my first ER visit (out of a total of 16… long story, but basically the nurse didn’t report the fall, and since I already had complained of abdominal pain, I was labeled as a drug seeker) screaming wordlessly at the top of my lungs. I couldn’t answer any questions; my husband had to tell them basic information, etc.

    Over the next 8 months, nothing was done about my back or my abdomen, so I was in a holding pattern of doctors scratching their heads and misdiagnosing me with bizarre conditions that I didn’t have (Ehler-Danlos, ACNES, hysteria) and telling me to just live with the pain. When I finally figured out which surgeon to see for the abdomen (doctors locally were absolutely hopeless with the abdominal injury, so I figured out what it was & took action), 90% of the TA was detached (and the TA was a mass of scar tissue), there were over a dozen muscle tears (and related scar tissue) in the rectus abdominis, and tears and scar tissue in both adductors. The back injury caused massive delays in figuring out what was wrong with my abdomen, and forced me to undergo bilateral hip surgery in addition to bilateral abdominal surgery. (The original injury was a small tear on the right side, but it spread and got way worse over time.)

    The surgeries were four months ago. Ever since, the back injuries, which are as yet untreated (except for one round of steroid shots last month in the facets, which didn’t change my situation), have been interfering with PT from the hip & abdominal surgeries, and I don’t know what to do at this point. My physiatrist keeps underselling how serious my back injuries are, even though I’ve told him repeatedly that back pain & related muscle spasms keep me from doing much PT for the surgeries. I can’t even do much walking, and lying on my back or belly is out of the question because it causes so much low back pain. He openly says that he doesn’t have much of a plan for how to treat my back, other than trying injections and PT (which has made my back pain worse, ironically; I’ve been struggling to do PT for a year, but it hasn’t helped much), and that the discs shouldn’t pose any problems at this point, so I am coming to you in hopes that you can guide me in what to do next.

    Do I address the annular tears first, or the bilateral SIJ dysfunction/pain? Do I address both issues at once? Should I try disc injections, even though I’ve read they can cause the discs to herniate? Do I try disc surgery? Should I continue with PT, even though it makes the lower spine / central pain worse? How do I fix the SI joints? Should I try prolotherapy? The SIJs hurt terribly and make walking long distances impossible. Though walking also irritates the central part of my low back (facet joints? discs? both?).

    I know you can’t tell me exactly what to do, but even some general guidance would help. I’ve seen over a dozen doctors for my back alone, and it took a fight just to get imaging done after the fall, which showed fresh annular tears and fresh bulges. (I know the bulges were fresh because abdominal CT scans taken days prior to the fall showed no injuries to my lower back at all.) I don’t know what to do or where to begin, or even what is really going on with my back, and it seems that neither does my doctor.

    Thanks for reading this. Please help.

    • Hi Layla,

      It’s hard to know what to say with regards to specifics as you seem to have both a rare and complicated collection of issues. It seems you know that though so hopefully I can offer some generalities and direction, as well as some impressions based on what you write.

      I haven’t treated anyone with a TA tear, but this sounds a lot like a hernia, and would think would be treated similarly. Unfortunately, there isn’t a lot of guidance as to what one should do for a hernia either, in spite of surgical repair being so frequent. Most surgeons I have heard of ask for 8 weeks avoidance of direct exercise, then gradually working back into usual activities. It’s not something that’s frequently sent to physical therapists. Thus I would think the general advice is sound. After 8 weeks if it were my abdominals I would start strengthening them with EMS, much as described in this blog. [edit, to add my electrode placements are a little different than what I show, so if you get a machine let me know and I’ll upload new images]

      The back pain, I would expect came on strong from inactivity, in what was likely a prolonged slouched posture. Because, what else are you going to with the abdominal and hip injuries. I would think the lessened abdominal integrity resulting from the tear, and likely increased spine mobility during daily activities, compensating for hip pain and lesser strength from the labral tears, didn’t do you back any favors either. Initial stretching and strains of the vertebral ligaments and discs won’t show up on an x-ray or MRI but can still be quite painful and cause “reactive” muscle spasms. For some reason this leaves most health care professionals very confused, and they’ll try make you feel better by stretching those spasms, making the underlying injury (what the spasms are trying to protect you from) worse. So don’t stretch your spine, that’s my advice numero uno.

      You say you don’t have Ehler-Danlos, but I would not be surprised if you don’t have some joint hypermobility, which contributes to all of the injuries. That said, I would think you would want to gradually strengthen everything muscular so that those muscles can better support all your joints. Living with the pain would definitely not be my plan A.

      I think if you try and fix any one thing first, everything on hold will only worsen, so you’ll never catch up. Total body strength and conditioning, starting very light, but if it’s too light for too long you won’t get ahead either. I’m still building out Spinal Flow as a site, but SF5 begun on Level-1, just a few of the exercises might get you going. My Spinal Flow User Rules are to increase reps/levels each time every workout, but in your case it might be more prudent to slow increases to every third workout on the same bodypart. An EMS machine with good electrodes and straps would probably be your best friend and with all your body parts needing it, if it were me I’d order a Globus Triathlon off Ebay direct from Italy. The USA imports all have their software dumbed down so can’t be programmed in the way I think is best. They’re less expensive from Italy too. My pads and straps kit, which you would almost certainly want to go with it is $120 shipped. I don’t have my store up anymore as I’m working on other things, but I could still ship them if you PM me.

      I would not get my discs injected, nor would I consider back surgery unless, your suffering neurological loss of bowel, bladder, or leg function and your surgeon says it’s an emergency. I hope that’s enough to get you started.

  4. Hi, Chad,
    Thank you so much for taking the time to reply to my comment. I know I have a mixed bag of damage; my physiatrist called me “a complex case” at my last appointment with him last week.

    To clarify, the TA muscle was literally torn off the pubic bone; it wasn’t a classic hernia, although initial work-ups assumed that (or something gynecological) was the case. The surgeon who worked on my abdomen re-attached the TA and repaired the torn adductors as well as the multiple tears on the rectus muscle that resulted from the TA’s having been detached for so long. I tried PT for the abdominal pain for seven months, but all it did was make the tear worse and intensify my abdominal pain. Core muscle injuries differ from traditional hernias; my surgeon, Dr. William Meyers, actually just published a textbook about them. They are often confused with traditional hernias and as such they are not treated correctly, with treatments usually making the injury worse. My initial injury wasn’t that bad, but it was left to fester a long time, plus the fall aggravated everything, so I wound up needing surgery. I don’t think I would have needed surgery if I’d been diagnosed immediately, as some people are lucky enough to experience.

    The back pain is the direct result of the fall that I suffered. All of the back injuries occurred simultaneously as a result of that trauma. I was groggy from anesthesia and so my muscles were not as “awake” as they otherwise would have been, hence, I think, the severity of the fall, as I was essentially dead weight hitting the floor with no reactive muscle tone. The fall is what caused the L3-4 & L4-5 discs to bulge and tear; the SIJs to become dysfunctional; the facet joints to become injured; and the hips’ labrums to tear. I really do not have Ehler-Danlos or anything like that. I think the TA being partially detached also contributed to the severity of the fall. It’s absolutely amazing how much damage that fall did. My back and hips were 100% symptom-free before that fall, even with the abdominal injury.

    I am extremely leery of back surgery, although I am curious about laser surgery to repair annular tears – any opinions? Why do you think I should avoid getting the discs injected? I’m leery about that, too, but it seems the only thing my doctor has to offer is injections. He even said so at the last appointment, that injections and PT are pretty much it. Except PT (including just walking) aggravates my back pain, and facet injections only worked for about 4 days. I am stuck in a pit I can’t get out of.

    Thank you again for taking the time to reply. I appreciate your advice and will avoid stretching my back. Does that include even “sleepy” stretching, the kind you do when you get out of bed?


  5. Oh, and I feel silly asking, but what is an EMS machine, how does it work, what are its limitations as far as results?

    I’m seriously considering prolotherapy for my SIJ dysfunction. In your experience/opinion, does prolo help this issue?

    Thanks again.

    • 1: Regarding the TA being torn like a hernia or differently, I would assume the healing times are similar. “Assuming” and taking an educated guess is about as good as you are going to get regarding how you should proceed as I doubt there is any research on healing times for your type of injury. If your surgeons text book says something different, I would defer to it.

      2: Impact injuries to the spine usually result in vertebral bone injuries, or Schmorl’s nodes (vertical disc herniations), rather than bulged discs or annular tears. I suppose it’s conceivable that you got a disc injury from a fall, but it’s probable that the fall made asymptomatic bulges, symptomatic. However, what caused the injury is meaningless. What matters is how to make things better, and almost certainly improving your posture will help as will lessening habitual spine flexion, while you gradually build up total body strength and fitness.

      3: My opinion is that I would not get laser surgery. I don’t think I could explain why in any kind of succinct way, except to say that I don’t think it will help.

      4: Cortisone injections make tissues weaker. Your tissues are already torn, thus even if they lessened pain and inflammation in the short run, you will likely be worse off in the long run.

      5: Research as shown stretching the spine upon awakening is the most dangerous time to do it. The discs are most full of water at that point and like a “most full” water balloon they are most ready to burst.

      6: EMS is electric muscle stimulation. Done properly, it’s a very effective way to strengthen painful muscles and lessen pain at the same time. Done improperly it’s worthless. I have an entire category of blogs on EMS/TENS that you should be able to find linked up to the right.

      7: When I read up on prolotherapy a few years ago I was unconvinced that it would help people with spine/SI pain. I have never recommended it. I did find EMS on the hip muscles fairly effective, as described in my year long log.

  6. Hi Chad,

    I am hoping you can help. I have had low right back/butt pain for 4 months. I have tried nearly everything without success so far. My PT said it was SI joint dysfunction but my spine specialist & mri said it was more likely due to L1S1 disc protrusion with some facet arthritis. It feels inflammed in the same spot all the time to the right of my tailbone when I clinch it. Up until May I was an active athletic 36 yr old male who loved to play tennis on the weekends. The only times it has felt good/normal has been when taking oral prednisone but the effects aren’t lasting. Can you please help steer me in the right direction?

    • Hi Nate,

      Just playing the odds I would vote in accordance with your specialist/MRI, however it could be more than one thing at the same time, which can make things confusing. On the bright side, and which this particular blog alludes to is that basic strengthening of the body, while keeping the spine neutral works for almost all the things it could be. I wrote it a couple years back when I was treating spine pain out of my clinic with a full gym, with all the weights and machines I could want. I still endorse that, but it wasn’t helping people so much who had questions, but didn’t have access to my gym. Potentially good news for you, is I’m teaching much the same thing but entirely with home exercise. C5 (control-5) to teach the postures and coordination and F5 (flow-5, though I should probably change that to force-5) to progressively build total body, and spine, strength and stamina, utilizing the postures and coordinated movements taught with C5. F5 is my current workout only because it turned out much better than just rehab. That’s the direction I would initially steer you, and depending how you respond I could hopefully offer more input. I would encourage you to also read my pages on the causes of spine pain, red flags, and the user rules. Together I would think that would keep you out of trouble, exercising and during daily life.


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