The pain is real!
But are “trigger points”? The more I learn, the more I wonder.
Trigger points (“muscle knots”) are an easy problem to like. We are happy to blame our pain on clusters of tiny patches of cramped muscle tissue, because it’s a powerful mental image that sounds like it feels and suggests an easy cure: just rub them out! Myofascial pain syndrome (“too many trigger points”) is a tempting underdog diagnosis that most doctors are oblivious to, so it’s also got a bit of that secret knowledge vibe. And it’s a great answer to questions almost everyone asks sooner or later: Why do I feel so stiff? Why do my muscles ache? Why does my pain go on and on? Trigger points are the gods of major gaps in medicine.
But the science of trigger points and myofascial pain syndrome is still weak and has yet to produce a proven way to treat pain. It’s all a bit half-baked … even after decades in the oven. Some serious, earnest experts have declared their annoyance with dogma and wild speculation about trigger points, and hype and big promises about treatments for them.1
And yet my ebook about trigger points and myofascial pain syndrome is my best-selling product. It is my meal ticket: it literally pays my rent, buys my food, and keeps the lights on. I wrote it because, during my 10-year stint as a massage therapist — 2000–2010, R.I.P.2 — I got more therapeutic mileage out of the idea of trigger points than any other clinical concept. In my experience, I was able to help more people in that way than any other, by far — good bang for treatment buck.
Or so it seemed. Unfortunately, having learned a lot about cognitive distortions in the last several years, I no longer trust “my experience” farther than I can throw it, and it’s all too possible that I fooled myself — as humans tend to do.3
I don’t want to believe. I want to know.
It’s outrageous! How can you be skeptical about trigger points when you’ve written a whole book about them?
I hear this quite often, but no worries, mate: although my skepticism might seem to contradict the purpose of my book, it does not.
We know something painful goes on in people’s tissues, acutely sensitive spots that are labelled “trigger point” pain, wisely or unwisely. No one doubts that: not me, not the harshest skeptics, not anyone. What is in doubt is the explanation, the nature of the beast. This article is about those doubts.
Armchair speculation about the biology of trigger points should not discourage anyone from rational, optimistic exploration of their treatment options. The purpose of this article is to address the reasonable and fair questions of skeptics about the science of trigger points. I hope readers will respect the fact that I’m willing to ask those questions myself, even if they don’t seem to be good for my bottom line.
Bullet points about trigger points: the highlights of my current position on the controversy
There’s a lot of article ahead — it’s a 12,000-word monster, which needs about an hour. If you just want to know my “official position,” these bullet points are all you really need, and they are an extremely careful distillation of many years of thinking and writing about this topic. I have probably never funneled so much work into a single short passage, and I may never do so again.
- The term and concept “trigger points” has a lot of baggage (like “subluxation”), but it’s still useful as a label for a symptom.
- The clinical phenomenon is all too real, but still unexplained.
- There’s lot of hype and B.S. about trigger points, and way too many professionals now believe in them like religion.
- The trigger point marketing horse is far ahead of the science cart, and most current methods of trigger point diagnosis and treatment are sketchy.
- Although trigger point science is half-baked, it’s better than many skeptics give it credit for, and it fares well in comparison to some far worse ideas in musculoskeletal medicine.
- I have moderate science-based confidence in the “tiny cramp” theory of trigger points.
- The kerfuffle over the nature of trigger points is a legitimate, ongoing scientific controversy— it is not a closed topic, and it shouldn’t be.
- Humble, conservative trigger point therapy is justified, but it should be considered “experimental.”
- There is plenty of overlap between decent trigger point therapy and an ordinary pleasant massage.
- Intense trigger point therapy—painfully strong massage and dry needling—is overprescribed and risky. Evidence for the efficacy of dry needling is too weak to justify the risks in most cases.
- My goal as a writer is to teach people about trigger points, including the skeptical perspective. When folks Google for “trigger points,” I want them to find my discussion of the controversies — not just the skeptical perspective, and definitely not just the true-believer perspective either.
The story of my evolution from trigger point student, to teacher, to skeptic
Once upon a time, I learned about trigger points from my first massage therapy mentor: she was my massage therapist from 1997 to 2000, during my own training to join that profession. As she worked on me, she explained most of what she was doing in terms of trigger points. Back then, it felt like I was getting special access to exotic knowledge. Certainly it was much more detailed, personal instruction in trigger point therapy than any of my classmates were getting.
Monkeys do what monkeys see, so of course I became a trigger point therapist — in fact, it mostly defined me as a clinician for the next decade. I wrote a book about it, because I am a writer: if I know things, I write them down. By the mid 2000s, other therapists were learning about trigger point therapy from me, from my book.
At that time, I had yet to hear a whisper of skepticism about trigger points. I didn’t hear one discouraging word until at least 2008.
But I had become a skeptic about a lot of other things in those years. I was getting fed up with the many bizarre beliefs and pseudoscientific practices that pollute the profession of massage therapy. Although I’d always had some unanswered questions about trigger points, they seemed like they were on scientific bedrock compared to the worst snake oils, things like zero balancing, therapeutic touch, reflexology, ear candling, applied kinesiology, homeopathy (uncritically embraced and promoted by many massage therapists). By 2010, I was a serious skeptic, well known for both my writing about trigger points and being a prolific debunker.
And that is when I finally started to hear discouraging, skeptical words about trigger points. Awkward! 🎶
A good skeptic looks inwards
So I did. And I realized, painfully, that what I had described for years as the “good, hard science” of trigger points was actually pretty weak sauce. And that clinicians believed it like a religion, and were overselling it egregiously. And this overconfidence was partly my fault. (Though, in my defense, I had always counselled humility and conservative treatment. Still, it was really quite awkward. Embarrassing even.)
And so I became a skeptic about trigger points too, sort of. In 2012 I wrote the first version of this article, in which I addressed the skepticism head on. I began to revise my book. Disclaimers about the uncertain science of trigger points popped up like weeds all over the website, wherever the topic came up (literally dozens of popular articles).
But it was all very inside baseball. My doubts weren’t about the existence of a painful problem, but about the biological explanation for it. In other words, it didn’t seem all that important to pass on to most of my readers at first. It was mostly just a rather advanced argument for experts.
In 2014, John Quintner, Geoffrey Bove, and Milton Cohen published a scathing critique of the idea of trigger points and myofascial pain syndrome in Rheumatology (Oxford), and suddenly everyone started taking sides. Soon many people I respected — people who had been my allies in other arguments about quackery for years — were loudly agreeing with Quintner et al. and denouncing trigger points in various ways. Those allies all saw the first version of this article, witnessed my diligent introspection, and assumed I was on their team.
And yet I wasn’t, not really. Not quite. In fact, most of the people who ever read the original version of this article seem to have concluded that I was on their side, regardless of which side that was. The article was actually quite neutral, and many reactions to it were an excellent demonstration of confirmation bias (selective perception). Many, many people overlooked the fact that I hadn’t really come to any kind of a conclusion. I had merely indulged my doubts and verbosely mulled over a bunch of miscellaneous wonky details.
Facebook became a big deal in this period, with large numbers of influential writers and teachers all constantly participating in public discussions and arguments about all of this, including — routinely — Dr. John “Trigger Points Are Bogus” Quintner himself. I am personally acquainted with many if not most of the dramatis personae, but I remained conspicuously shushed until 2016, except for an occasional show of public respect for the skeptical position.
There have now been years of ambiguity and fence-sitting while the argument has gotten more and more polarized around me. I never got off the fence, because I kept having experiences like this…
The ultimate trigger point treatment anecdote
The world of trigger point therapy rests mainly on the back of anecdotes like these, and not on settled science. Most massage therapist have stories like this. But this is a particularly good one: the apotheosis of trigger point treatment success stories.
During a family visit, my wife’s uncle was suffering from a sickening ache on the front of his shoulder, like a toothache in his anterior deltoid. He was a weathered, cheerful former farmer who’d lived hard and wasn’t the sort to complain or ask for help, especially from his nephew-in-law the massage therapist — a profession that probably seemed a bit strange to him. However, he was pale with pain, and I’d never seen him so subdued, so he accepted my assistance without much fuss. A quick clinical quiz determined that the problem had been worsening steadily over a few weeks, and had driven him to the doctor where it had been chalked up to arthritis. And yet the pain was off the charts in a joint that is rarely afflicted by arthritis, and had been worsening much too quickly for that diagnosis. If this was arthritis, it was certainly an odd example of the breed! He’d also been told it might be bursitis, a common misdiagnosis that was an even worse fit. And “maybe frozen shoulder,” yet another poor diagnostic fit (his range of motion was normal despite the discomfort, so the signature symptom of that condition was missing).
I recognized the signs of what I knew as an active muscle knot or “trigger point.” (And, honestly, I would probably still call it that today — for lack of a better term. This naming problem will come up again.) I recognized the location as being strongly characteristic of a typical pattern of referred pain from the infraspinatus muscle, and one of the more dramatic examples of that odd phenomenon: poke the shoulder blade in back, but feel it in the deltoid muscle on the front of the shoulder. I prodded the infraspinatus just so, and sure enough he responded with surprise: “Yeah, hey, wow, that’s it! I can really feel that in the front of my shoulder.” I rubbed the spot with a practiced thumb for all of five minutes, and …
He was cured. Immediate, total, permanent pain relief. I fixed him in less time than it takes me to make coffee.
My uncle-in-law spent the rest of that weekend swinging his arm around, chuckling, and saying things like “Who knew?” and “Well, damn, ain’t that something!” He brought it up every time we visited after that. He mentioned it the last time I saw him, just recently, near death — it was his defining memory of me.
And that is the most dramatic treatment anecdote of my career. It was not an unusual sort of clinical experience — I had many similar ones — but it was the high water mark, the best of the best, the most unqualified victory I ever had over pain. The “magic hands” myth was on full display, because the spot I chose to treat was so curiously remote from the pain, so counterintuitive. Nothing is better for a massage therapist’s reputation! It seemed like a miracle to him not only that I cured him, but that I did it by pushing on a spot on the “wrong” side of his shoulder.
The trouble with trusting my experience
I do not entirely dismiss experiences like that, but I have learned to be deeply suspicious of them. They were good enough for me when I was a massage therapist … but I’m not a massage therapist any more. My career has taken a strange turn from massage therapy to science journalism, and it has exposed me to countless worrisome examples of seriously flawed clinical reasoning … most of them supported mainly with anecdotes just like that one.
You can get the same kind of stories out of any practitioner of rank quackery, such as homeopaths, reflexologists, and faith healers. For centuries, bloodletters told stories like that.
The three most dangerous words in medicine: in my experience.
Mark Crislip, MD
Experience is not enough. Things are not always what they seem, and the mind is afflicted with many common reasoning errors and illusions. Throughout history, people have believed really goofy things based on “experience.”4 It has become my job to study and understand those mistakes. Many of my own beliefs, one by one, have fallen like timber, hacked down by new critical thinking skills. I no longer believe 80% of what I did in my first couple years of selling therapy.
Most of the low-hanging empirical fruit is gone from medicine. The handily tested theories have been tested. The only challenges left now are the slow-motion and multifactorial, the microscopic, subtle and psychological: messy etiologies, vastly more complicated medical puzzles than, say, figuring out how to prevent cholera.5
Despite such confounding complexity — or maybe because of it — deeply flawed and biased personal experience is still constantly used as the main justification for all kinds of pain treatment methods. We must beware!
Trigger point science is a bit half-baked
For years, the introduction to my book clearly stated that “trigger points are good, hard science.” How quaint! I was wrong.
There is quite a lot of science, and some of it is interesting and good science — generally better than fascia science, for instance6 — but as a whole it doesn’t add up to much yet. It’s mushy, not hard. And so I changed the phrasing of the introduction early in 2012, a few years later than I should I have.
That’s my opinion, but I’m not alone. Here’s a good example of a particularly scathing expert opinion: Dr. Fred Wolfe, a rheumatologist, calls trigger point science a kind of pseudoscience, “cargo cult science” and “pseudo-pseudoevidence based medicine,” in which the so-called evidence “never reaches the level of evidence, and assertions, ‘facts,’ definitions, and beliefs are derived without testing or without adequate scientific basis.”7 That double-pseudo is quite the slap: he’s saying that trigger point science is even worse than (single pseudo!) pseudoevidence-based medicine, or medicine based on rather low quality evidence.8 This is from an articulate expert, one who worked with Travell & Simons directly, and yet he is quite exasperated with the so-called science of trigger points, and by no means is he the only one.
The more I read the more I doubted. The book [the Travell & Simons “Bible”] represented opinion, not science. None of the trigger points or their treatments were validated; none were tested for reliability. There were almost no studies … just testaments. Most of the perpetuating factors were plain wrong, and represented outdated, overthrown junk science.
Dr. Fred Wolfe, rheumatologist, describing his reaction to the “bible” of trigger points
The perpetuating factors were the first things that bugged me about those books, too. Dr. Patrick Wall, a British neuroscientist and “the world's leading expert on pain,” also saw trouble in trigger point land, and referred to it harshly when he wrote his foreword to what is something of a “sequel” to the Travell & Simons text:
Hopefully we are emerging from an era of fantasy explanations for real phenomena. The authors certainly have to face a community of therapists who are obsessionally committed to explanations for disease and for therapy unsupported by a scrap of evidence except for their claimed therapeutic success.
Professor Patrick D. Wall, FRS, DM, FRCP, in the Foreword to Muscle Pain: Understanding its nature, diagnosis and treatment
I feel the need to challenge trigger points as a concept because I don’t trust my own experience any more, and because the science of this kind of pain is more limited and less illuminating than I once thought. Although there’s definitely a phenomenon in need of explaining, much less can be said with confidence about the nature of that phenomenon than I would like. So I am slowly, steadily updating my book with the general goal of presenting the notion of a “trigger point” as a weak metaphor — much like the more obviously quaint “muscle knot” — more than an actual known thing (a lesion) that resides in meat. It will probably become a book more about the subjective experience of muscle pain than trigger points. Fortunately for me, muscle pain — the sensations of stiffness, aching, or even agony in muscle — is a worthy topic, whatever the etiology, however it works. So I still have a book, and it is still worthwhile.9
But I condemn cultish and dogmatic promotion of trigger point therapy as a panacea, or even just the overselling of the benefits — all of which is much too commom. Many common practices under the banner of myofascial pain syndrome are nonsense or dangerously close to it.10
A key premise for doubt: pain cannot be “in” meat
Tender spots certainly exist, but it seems the only purpose for insisting that they exist in a muscle is to justify jabbing, poking, squeezing or otherwise assaulting them with various implements, including needles.
John Ware, PT, commenting on “The trigger point strikes … out!”
The most basic reason for my trigger points doubts is that they may not be what they seem to be. Clearly they seem to be “muscle pain,” but it’s definitely not confirmed that there is anything wrong with the muscle itself. (There might be. And there might not be. I’ll be returning to this question later.) The words muscle pain describe a subjective experience — one that I constantly endure, along with millions of other people — but that doesn’t mean the muscle is where the trouble is.
Pain is an experience generated by the brain, based on pre-conscious processing of many signals (not just dumbly reporting whatever nerve endings detect in the tissue).11 So what seems to be muscle pain could be more akin to phantom limb pain, a ghostly projection, and not an “issue in the tissue.” This possibility has the potential to explain quite a bit about the phenomenon of so-called trigger points. Even if there is a tissue issue, it might not be all that important — just the tip of an etiologic iceberg.
Even the clearest localization of pain in one area may, in fact, be originating from a distant area … . The reference of pain implies the existence of convergence of inputs within the spinal cord. This leads to the necessary involvement in central neural circuits in the simplest of peripheral disorders. It also leads to the possibility that the basic disorder is entirely central …
Professor Patrick D. Wall, FRS, DM, FRCP, in the Foreword to Muscle Pain: Understanding its nature, diagnosis and treatment
The texture of the problem
The sensitive spots we call trigger points are not clearly associated with any clear clinical sign, such as tissue hardness. But supposedly they are! Supposedly every trigger point is a painful, tight patch of muscle tissue — a palpable lump or muscle “knot.” Also supposedly found in a taut band of tissue, which also twitches when provoked. This is dogma. It’s taken for granted by most of the world’s massage therapists, and it’s the main substance of nearly every published definition of trigger points. According to hundreds of thousands of professionals, trigger points are lumps in muscle.
But are muscles actually tight or hard where they hurt? Believe it or not, this really is not clear, and this is one of the main ways that the science of trigger points is pretty half-baked. This question could have and should have been clearly answered a long time ago … but it truly has not been.
In a nice little 2010 experiment in the Journal of Pain,12 the hardness of the trapezius muscle was tested and compared with sensitive points, before and after intense exercise. In a dozen healthy patients, the two “typical locations for tender points” were not just soft, but the softest spots in the muscle — the opposite of what most people would expect, and the opposite of what we “know” from trigger point lore. In general, “a heterogeneous distribution of pressure pain sensitivity and muscle hardness was found.” Translation: the conventional wisdom that you’ll find the most pain at “tight” spots in muscles is probably a misleading oversimplification, at best.
Oh, dear. That’s not how a description of trigger points should sound! This is a bit of a problem. It’s not a large experiment, but it didn’t particularly need to be to make this point. Even a small test should have clearly showed that the sorest spots are the hardest — if they really are. The muscle was particularly well-chosen: the trapezius is possibly the most massaged of all muscles, and assumed to be one of the “knottiest” in the human body. If sore spots don’t correlate well with texture in the trapezius, they probably won’t anywhere else either.
Trigger point doubt #1: What if therapists can’t find them?
In the Andersen et al. study just discussed, sensitivity was both measured with a therapist’s “magic hands,” and more objectively with a tool: a pressure algometer. Guess what? Thirty percent of the sensitive spots identified by hand were not identified by the more accurate algometer.
Magic hands? Magic algometer, more like.
Diagnostic accuracy is a problem for trigger points. If different professionals cannot reasonably consistently find the same trigger points in the same patients, then trigger point therapy has a practical problem at the least, or an ontological problem at the worst. Either it means that trigger points are quite difficult to detect (that’s the practical problem) … or that they aren’t actually there in the first place (and that would be the ontological problem).
This sort of thing is mainly determined using inter-rater reliability testing, which is quite persuasive: when two therapists tested separately point to different spots and say, “Well, there’s your problem,” people can easily see that someone must be wrong. It is difficult indeed to treat what you cannot find. (Although not as impossible as it might seem at first — stay tuned.)
Probably the first reliability study of trigger points was in 1992.13 Dr. Fred Wolfe’s description is more dramatic than an episode of Downton Abbey:
In 1992, we performed a study of trigger points. A group of four myofascial pain experts, selected by Simons and including Simons, blindly examined four patients with myofascial pain (MFP). The examiners were allowed to take as much time as they needed; they could examine but not interview the patients. As we had mixed MFP patients with those who had fibromyalgia, it was a blinded experiment. These MFP experts were no ordinary examiners. They were the best. They wrote the book, they did the lectures. But, in the end, they could not find or agree on the trigger points. It was a disaster. The examiners were distraught. After the results were in, they protested and wanted to change the protocol and purposes of the study (post hoc). It wasn’t fair, they said. Glenn McCain, one of the rheumatologists, exploded in outrage. It was intolerable, he said, to alter study results. He was so angry that the opposition stopped. Subsequent delays and disagreements over the methods, results and discussion continued and almost prevented publication. But time took over; people forgot, and the study — a little toned down — came out in the Journal of Rheumatology. If we believed in trigger points and The Trigger Point Manual before, we were a lot less secure in our beliefs now.
For all that, the final wording of the paper does not seem quite like a “disaster,” and of course there is probably another side to the story. You can easily see signs of the tense negotiation over the wording in the abstract. On the one hand, there were “problems with reliability.” On the other hand, with a “more liberal definition of trigger point,” they were indeed found. “Our data are exploratory and tentative” and they “suggest that attention to definition and reliability are required to advance our knowledge.” Ya think?
Some other early studies of this kind were quite positive. Sciotti 2001 is a good example: they conducted a well-blinded test with four experts and 20 patients and concluded that “two trained examiners can reliably localize latent TrPs with a precision that essentially approaches the physical dimensions of the clinician’s own fingertips.”14
The data were indeed not enough to settle the question, and 20 years later the reliability evidence remains about the same: inconclusive. Or maybe discouragingly non-positive. Or perhaps encouragingly non-negative. Depending on how you look at it. (That ridiculous serving of word salad will start to seem almost palatable as we proceed.)
A 2009 paper15 surveyed all the research available up to that point: research that had not “reported the reliability of trigger point diagnosis according to the currently proposed criteria” (exactly echoing Myburgh et al from the year before16). The authors also explained that “there is no accepted reference standard for the diagnosis of trigger points, and data on the reliability of physical examination for trigger points are conflicting.” In other words, some studies were positive, and some were negative, and no one quite agreed on what we’re looking for (a problem in itself).
Fast forward to 2017 and another review of nearly the same data by Rathbone et al.17 Lucas et al and Myburgh et al used data from five and nine studies a decade earlier, and this review looked at six. They didn’t have enough data for meta-analysis of intrarater reliability, but they did for interrater reliability (inter is the consistency between different people, and intra is the consistency of assessments by the same person). They had to “estimate” an inter-rater reliability of 𝛋=0.452 — a rather precise estimate! With wide error bars: 0.36–0.54. Of the specific criteria used to determine the location of trigger points, the most reliable in their data were localized tenderness at .68 and pain recognition at .57.
Those are actually non-terrible reliability scores — “fair” to “moderate,” even “substantial” for the best criterion18 — but the authors concluded that “manual palpation for identification of MTrPs is unreliable.” Technically true, but…
Diagnosis is hard, and low diagnostic reliability is actually just medical business as usual.
Results like this are often cited by skeptics to argue that it’s “impossible” to diagnose trigger points, which is also often used as a premise for the even more skeptical argument that they don’t even “exist” (as a palpable lesion, anyway). “Diagnosis is unreliable because there’s nothing there to detect,” goes the logic, and that carries some weight… but it’s hardly the whole story.
Just because something is hard to diagnose does not mean it doesn’t exist — something every chronic pain expert ought to appreciate. Most attempts to detect pathologies — very, very real pathologies — are technically “unreliable,” falling well short of a score of 𝛋=1.0 (perfect agreement), but still much better than 𝛋=0 (coin flipping agreement). This result for trigger points, if the data can be trusted, is actually pretty good, and roughly on par with many other common, mainstream diagnostic methods.
Of course more reliability would be great! 0.452 is not good reliability. But the same is true for literally hundreds of other well-studied diagnostic challenges in medicine.
If there was nothing to detect, these reliability scores would be much worse. So now you start to see why the evidence might be “encouragingly non-negative.” Before we give up on diagnosing trigger points by feel, let’s ask a radar operator first. From radar science, we learn that reliability isn’t everything.
Bogey at 10 o’clock! Reliability isn’t everything
Diagnosis is detection
“Signal detection theory” started with radar in WW II & is relevant to many modern diagnostic challenges.
Difficulty detecting something does not mean it isn’t there or that it isn’t worth trying. Lots of things worth looking for are hard to find, the process plagued with inaccuracy and false positives and negatives.
Like enemy fighters.
“Signal detection theory” started with radar in WW II. There was a painful trade-off that afflicted the technology: you could dial up the sensitivity of the radar to be sure of detecting every invading plane, but then you’d end up scrambling your pilots to defend against invading geese as well. Or you could dial it down to prevent those false alarms … but then you’d (disastrously) miss genuine enemies.
It’s a hell of a dilemma, and as unavoidable as gravity: it crops up everywhere that anyone tries to separate “signal” from “noise,” with any attempt to detect anything indirectly. It is the same as the trade-off between diagnostic sensitivity and specificity in medicine. Both are highly desirable, but you tend to get more of one only at the expense of the other. Just replace “enemy fighters on radar” with “tumours in MRI scans,” and you see how similar these problems are. Radar operators were “diagnosing” invading planes. Radiologists are detecting invading pathologies.
If trigger points are a detectable phenomenon, how hard might it be to detect them? All indirect detection challenges are tricky by nature. Consider this fascinating recent example, where researchers discovered that fMRI studies of brain activity frequently “find” signals “when there wasn’t really anything happening.” Uh oh! Brain activity signatures are real, but detecting them is … well, “difficult” doesn’t really do it justice.
Genuine R-O curve napkin scribbles
To bone up on my signal detection theory, I asked my buddy Dr. Rob Tarzwell to give me a brain dump on the subject over beers & he drew this here receiver operator curve diagram on a napkin. Rob is a former air force man & a rare double-speciality physician — psychiatry & nuclear medicine — so he’s absurdly qualified to scribble on this topic. The upshot? The graph demonstrates the natural trade offs between specificity & sensitivity & that more expertise can only get you so far. In other words, some things are just bloody tricky to detect & subtle nodules in muscle may well be among them. Also: I am blessed with frighteningly smart drinking buddies. See the Facebook discussion about this scribble.
Palpatory pareidolia: dialing up sensitivity
The problem of detecting lumps in muscles is greatly complicated by pareidolia, a proven and common kind of illusion in which we perceive what we want or expect, rather than what is real. It literally happens to the best of us. Pareidolia occurs in any situation where humans are trying to interpret unclear signals, and it is always amplified by a clear bias. And financial interest. And it certainly applies to diagnosing anything by feel — “palpation.” For a much more detailed discussion of this, see Palpatory Pareidolia & Diagnosis by Touch: Tactile illusions, wishful thinking, and the belief in advanced diagnostic palpation skills in massage and other touchy health care. This section is just a quick summary of PP as it applies to the question of trigger point.
For many massage therapists, trigger points as a palpable entity are accepted dogmatically, and it is the basis for a lucrative career. If a diagnostician expects to feel trigger points, she probably will. If trigger points really are bumpy, palpatory pareidolia will cause a lot of overdiagnosis. It will be one of the main reasons that diagnosis is hard.
But what if trigger points are not actually palpable at all? Alas, palpatory pareidolia is all-too capable of disguising this fact. Therapists will probably feel them anyway, because they think they should. You may be skeptical, but it is actually almost routine for large numbers of perfectly intelligent human beings to suffer from pareidolia-powered misperception. Our brains really are that weird and fallible. (In fact, pareidolia is nothing.19) This has happened many times in history. If you accept pareidolia as a reality (and you really can’t avoid it), then you also have to assume that therapists will find what they are looking for, whether it is actually there or not. It means that diagnostic sensitivity will be off the charts at the expense of specificity, and so the rate of false positive trigger point “finds” will be off the charts.
I spent many years overconfidently “detecting” trigger points in tissue, and I am fully, humbly willing to admit that I was probably wrong about many of them, and it could be even worse than that. That does not mean I was wasting my time, or that my clients were not enjoying a perfectly meaningful and useful massage experience. But it is certainly possible — maybe even likely — that I misinterpreted the biological meaning of what I felt. Day in. Day out. For years.
The first principle is that you must not fool yourself & you are the easiest person to fool.
Difficult is not impossible
Some clinical phenomena are more difficult to assess and we expect diagnostic reliability to be poorer for them. Obviously one wants to be wary of using this as a lame excuse for poor reliability (special pleading20), but neither do we want to ignore the obvious: some diagnosis is just difficult. If trigger points actually cause lumps in muscle tissue, it probably is tricky to find them reliably. Lumps under thick skin are not exactly a palpatory slam dunk!
In attempting to diagnose trigger points by feel, there are many potential false negatives and positives. It may be quite a needle-in-haystack challenge to find a trigger point in muscle, with many ways to either miss one or be fooled into thinking you’ve found one. This is also true of many medical conditions, which is precisely why palpation is almost never the sole diagnostic method in a medical context.
|false negative||=||It’s there! But it’s hard to feel. It might be too small (microscopic or close?) or too subtle (maybe only 10% firmer than surrounding muscle). Maybe it’s too buried, or adjacent to disorienting anatomy (sometimes hard to tell healthy bumps from the unhealthy ones).|
|false positive||=||Mostly caused by normal bumpy stuff in anatomy — decoys! Powered by palpatory pareidolia. Could be pure illusion. Misinterpretation of variations in muscle tone that have nothing to do with trigger points.|
For contrast, poor diagnostic reliability for chiropractic subluxations would be considerably more damning, because there are a lot fewer possible subluxed joints in the spine than possible trigger points in muscle — fewer potential false negatives or positives! That means that chiropractors would look a bit ridiculous if they couldn’t agree on a diagnosis when choosing from only five lumbar joints. Pop quiz: can they? Answer:21
Context matters. Less than stellar inter-rater reliability doesn’t mean much on its own if you don’t know much about the phenomenon you’re trying to detect. But when the phenomenon you’re attempting to detect is debatable and hypothetical in the first place, lacks any corroborating objective evidence, and it all could be explained by pareidolia … then poor reliability becomes a more serious basis for concern. Detecting cancers is tricky too, but it’s also a lethal certainty that they are there to be found. One of the main reasons that I have “trigger point doubts” is that the detection challenge isn’t the only concern about trigger points.
Mitigating factors: the reliability problem is not in itself a deal-breaker
We do not yet actually have smoking gun evidence of poor reliability. If anything, we have evidence that it’s actually surprisingly non-bad for something so inherently difficult. Based on fairly crappy data. The science cannot tell us whether trigger points are genuinely lumpy but hard to detect … or non-lumpy in the first place.
The cost of a diagnostic miss may be relatively trivial. It’s ruinous to diagnose a cancer where there is none, but not so much with trigger points.
Diagnostic precision may not be critical to the value of the therapy. Does it actually matter if you know exactly where a trigger point is? Massage can easily cast a wide “net” of pressure, touching most or many trigger points without precision.
With well-established official guidelines and proper training, accurate diagnosis might be a snap, and there is already evidence that skill could make a difference.22 The therapists of the future may pass reliability tests with flying colours. But there are no such guidelines, and most professionals probably do not even know what the proposed guidelines are! And so for now trigger point “diagnosis” is obviously a bit dodgy in practice. Which may or may not matter much. As long as you don’t mind your therapist pretending to know the unknowable.
Diagnostic reliability is still a legitimately open question. It is likely to be poor even if there is a phenomenon to detect, due to poor training and experience, lack of standards, and an inherently difficult challenge. However, there are good reasons to fear that low diagnostic reliability is actually caused by the absence of a palpable phenomenon. We simply do not yet know which explanation is correct.
Trigger point doubt #2: What if trigger point therapy doesn’t work?
Even if trigger points are real, it doesn’t necessarily mean we know how to fix them, but that’s the hope. With all this “trigger point therapy” out there, it’s reasonable for people to assume that it must work, and certainly trigger point therapists believe that it does.
We don’t need to understand how a treatment works to test if it works. Science can always measure treatment outcomes even if it can’t explain the weird biology that powers those effects. Changes in pain and function are fairly straightforward things to measure. A good pain-killing benefit can definitely be detected.
And so, if trigger point therapy is more than a shot in the dark, then patients should clearly feel better after trigger point therapy. Indeed, any kind of massage should relieve trigger point symptoms, because it should have at least some effect on trigger points — while massage that focusses on finding and treating trigger points should produce even more impressive results. And other kinds of treatments that target trigger points — especially dry needling, injections, and stretching — should be supported by promising evidence at least.
All of this should be reasonably clear from clinical trials, if trigger points are real and trigger point therapists are even half-right about how to treat them.
So what does the evidence say? Almost nothing, unfortunately.
Trigger point masssage has never been subjected to even one sufficiently rigorous clinical trial. There are only about a dozen studies worth knowing about,23 and all have serious flaws and all were conducted by researchers with a high risk of bias. Most report only minor benefits, and a couple are actually blatantly negative despite their positive-sounding conclusions (if you look at the actual data). Only one reports a more robust effect,24 but it’s based only on a single measurement taken immediately after treatment — a benefit that could evaporate within seconds for all we know.
The bottom line is clear: the evidence is promising if you’re looking at it from the perspective of a trigger point therapist. If you’re a skeptic, it looks more like damningly faint praise. And if you don’t have a dog in the fight? In that case, it’s just inconclusive.
One of the signature symptoms of quackery is a long-term failure to produce good evidence of efficacy, even after many years. Classic examples of this problem include homeopathy25 and straight chiropractic.26 The wheels of science don’t always turn quickly, and it can be logistically and economically difficult to get proper studies done. The modern era of Travellian trigger point therapy began at least 25 years ago, launched by credible physicians who strongly declared the need for research27 — so you’d think it might have gotten off on the right foot, research-wise. And indeed there is a lot of research. Unfortunately, almost none of it has focused on outcomes … which is the next problem.
There is a groan that unites men and women, rich and poor, in any nation. These [muscle] pains are “explained” in every culture, but the universal fact of this persistence must mean that no adequate therapy exists.
Professor Patrick D. Wall, FRS, DM, FRCP, in the Foreword to Muscle Pain: Understanding its nature, diagnosis and treatment
Another signature symptom of quackery is to endlessly emphasize only basic biology and hypothetical treatment mechanisms, instead of treatment outcomes, touting reams of published research about how and why treatment supposedly works before we even know if it actually does.28 The best current example of this is the fascia fad,29 but trigger point science is disappointingly similar. There is a lot of trigger point research, but much of it is cryptozoological in character: exaggerating the importance of anecdotes, indistinct footprints, and blurry photographs, because more direct and relevant evidence of the monster seems to be perpetually unavailable.
So there’s suspiciously little of the right kind of evidence, and the clock of history is ticking loudly. At what point does the absence of evidence become damning? At what point do weakly positive results constitute evidence of absence? And are we there yet?
My opinion is: the deadline is looming, but we are not there yet.
Acupuncture crossed the line about a decade ago, chiropractic subluxation crossed it twenty years ago, and homeopathy crossed it (at least!) thirty years ago. It isn’t too late for fascia-inspired therapy to demonstrate efficacy, but I doubt that it will. And trigger point science, I think, is just still in a legit limbo. Just because a bunch of blind men grab onto an elephant and make amusingly different inferences about the nature of the beast does not mean that there is no beast.
Bigfoot hunters have already had their chance and failed.31 Trigger point research is only about a third as old, and it has always been a much trickier scientific question. I wouldn’t have given up on bigfoot in the 1960s, and I’m not ready to give up on trigger points yet either. I will do the only thing I can: wait for more and better evidence.
Trigger point doubt #3: Location, location, location
I have often been troubled by glaring inconsistencies and loose ends in the classic trigger point texts, the “big red books” (Travell, Simons),32 and also the more recent and general blue book, Muscle Pain (Mense, Simons).33 The most irritating problem is the puzzle of trigger points that seem to exist entirely outside of muscle. How can you have little pathological contractions in non-contractile tissue?34 What are they?
The red text describes them without even attempting an explanation, and the blue book acknowledges the problem … and then refers the reader back to the red!
The dominant theory of trigger points is that muscle tissue contracts excessively, generates a lot of metabolic waste products, which poisons the tissue and perpetuates a vicious cycle. Trigger points are by (this) definition found not only in muscles alone, but in the hearts of their bellies, at their motor end plate zones, where nerves meet the muscles. Travell and Simons believed this to be the precise scene of the crime, on the basis of a few lines of evidence:
The critical trigger point abnormality now appears to be a neuromuscular dysfunction at the motor endplate of an extrafusal muscle fiber.35
Much depends on that sentence. Although they called it a “hypothesis,” they used it more like a fact: it is stated repeatedly with considerable confidence in both texts, old and new, and is then used freely as a major premise for other lines of reasoning. If the motor end plate is really where the dysfunctional action is, that would certainly be an anatomically definite guide to treatment: motor end plates mark the spot. And indeed both texts go to some trouble to explain exactly where motor endplates are in various types of muscles, both explaining and showing with a series of nice diagrams:
Understanding the location of motor end plates is important for the clinical diagnosis and management of myofascial trigger points. Since the pathophysiology of trigger points is intimately associated with the end plate, one expects to find trigger points only where there are motor end plates. End plates in nearly all skeletal muscles are located near the middle of each fiber, midway between its attachments. (p 234)
It’s cut and dried: the conscientious reader of the trigger point bibles, old and new, will take home the message that trigger points are in muscle middles. The theory actually requires it.
Theory, meet practice: trigger points without muscle
As every alert clinician knows, people seem to have trigger-point-like sensitivity and pain anywhere and everywhere … often far from any motor point. Our subjective experience of body pain includes many examples of focal sensitivity to pressure on tissues, particularly tendons and bony outcroppings. Furthermore, these often appear to respond to treatment just like trigger points; there is little functional difference. All without touching a muscle fibre, never mind a motor point.
And here’s where things get really interesting: Travell and Simons knew this too. For instance, just one paragraph in Muscle Pain is devoted to this problem, short but precise and clear:
Nonmyofascial trigger points. Trigger points that refer pain may also be observed in what appears to be normal skin, scar tissue, fascia and ligaments, and the periosteum. The reason for sensitization of nociceptors at these sites needs to be clarified but must be different from the trigger point mechanism that relates to dysfunctional motor end plates. These nonmyofascial trigger points are considered in detail elsewhere. (pp 231–32)
Must be different? That’s an understatement!36 The paragraph concludes with an endnote, presumably referring me to a source that considers nonmyofascial trigger points “in detail.” Great! I thought. Maybe something I’ve missed all these years! Maybe an answer to the puzzle! I flipped eagerly through the references, feeling that pleasant intellectual buzz one gets when flirting with a revelation. But my heart sank when I arrived at the endnote: a reference to Travell and Simons! Which doesn’t have any answers either.37
How big a problem is this discrepancy?
I have two distinct kinds of clinical and personal experiences — which I trust equally well, or equally poorly, but equally — and they cannot both be explained by the same conventional wisdom. So something is almost certainly seriously wrong with this picture. But … how wrong?
There’s nothing about the clinical phenomenon of non-muscular trigger points that means that the conventional wisdom is actually incorrect. To use cryptids as an example again, there could be many distorted and dishonest reports of monsters and real monsters as well. So too there could be trouble at motor end plates and [insert some other kind of trouble] in non-muscular tissues. Indeed one of the main reasons almost everything about this topic is difficult is that there are probably many overlapping mechanisms for body pain in general and sore spots in particular.
Nevertheless, it’s a helluva loose end, and I’m hardly the first to notice it. (Even Travell and Simons and Mense noticed it — they just didn’t explain it. Or even try.) It must be dealt with, sooner or later, one way or another. This is exactly the kind of thing (one of many) that led Dr. John Quintner to criticize the energy crisis hypothesis more than 20 years ago, and propose a different explanation for what trigger point pain really is — one that did not fall apart when it didn’t seem to be coming from inside a muscle.38 And indeed he’s still busily promoting that hypothesis the last time I noticed in 2020.
Whether Quintner’s idea was/is correct or not is beside the point: what’s important is that he was arguing (more than 20 years ago) that the focus on muscle “has directed attention away from other possible explanations,” and it simply can’t account for all the symptoms we observe in the wild. It couldn’t then and it still can’t now. That simple inconsistency packs more skeptical punch that anything else I’ve discussed so far. It’s hard to have clinical confidence in hunting for trigger points at motor points when it’s so clear that something else must be going on. If extremely trigger-point-like phenomena can occur right next door in ligament, tendon, periosteum, and skin, then it seems silly to place your bets on the motor points: they are not the thing, just a thing, maybe.
Non-myofascial trigger points are a problem for the conventional wisdom. Although it might just mean that the energy crisis hypothesis is merely incomplete, and we need some other mechanism just to deal with those other trigger points, my personal hunch is that it’s worse: whatever is going on around motor end plates is just one facet of a deeper, more general problem which has still not been identified. I doubt that trigger points will ever be correctly, meaningfully described as a disease of neuromuscular junctions. It’s either wrong, or too incomplete to be considered more than a slice of the truth.
Trigger point doubt #4: What if there’s no lesion?
So far, I’ve been trying to guess about the nature of trigger points based on indirect evidence like diagnostic reliability, treatment efficacy, and inconsistencies in the stories experts tell about trigger points. These are important things, but in the end they could all be trumped by the presence of a lesion — something identifiably wrong with the tissue. There is no disease without a lesion (well, not entirely — but it’s a solid rule of thumb).
If there really is a lesion associated with the clinical phenomenon known as a “trigger point,” then does it matter if it’s hard to feel? Does it matter if treatment is hard? Lots of horribly real health problems are hard to diagnose and cure! Many of the doubts and concerns discussed so far are a moot point if the lesion question can be answered.
If a lesion exists, it is undoubtedly a subtle one, and this is not unusual in medicine and pathology. While it would be genuinely shocking to discover that there really are large, hairy, primates skulking in the coastal forests of North America, unconfirmed for decades, it would definitely not be shocking to confirm that, yes, muscle does indeed misbehave in predictable and painful ways at the cellular scale. Biology is vast and both muscle histology and pain science are still surprisingly primitive.
That confirmation has not happened yet, obviously.
But not for lack of trying. There’s plenty of science on the topic, too much to cover properly here, so I’ve dedicated a separate article to it:
This is what I think about the evidence of lesions … for now
I think it’s good enough for moderate confidence that trigger points are indeed associated with a muscle lesion, and the characteristics of that lesion are consistent with the more specific integrated hypothesis — that is, the lesion is basically a focal contracture, a “tiny cramp.”
High confidence is not justified by the evidence available so far. But it is enough for careful presumptive treatment, with informed consent.
And I think it’s enough to justify more research. There’s enough smoke that continuing the search for the fire seems reasonable to me. The topic should not be entirely closed, as some skeptics have “proposed” (read: haughtily demanded au nauseum).
And so, after all these doubts, I suspect that there probably is a lesion — and what’s in doubt is mostly just our ability to diagnose and treat it, and the ethics of overconfident health care professionals who oversell, fail to disclose the uncertainties, and treat too aggressively, risking harm to their patients without adequate justification.
That is my position as of mid-2020. I will be watching the evidence closely.
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About Paul Ingraham
I am a science writer in Vancouver, Canada. I was a Registered Massage Therapist for a decade and the assistant editor of ScienceBasedMedicine.org for several years. I’ve had many injuries as a runner and ultimate player, and I’ve been a chronic pain patient myself since 2015. Full bio. See you on Facebook or Twitter.
- Cramps, Spasms, Tremors & Twitches — The biology and treatment of unwanted muscle contractions
- Science versus Experience in Musculoskeletal Medicine — The conflict between science and clinical experience and pragmatism in the management of aches, pains, and injuries
- 34 Surprising Causes of Pain — Trying to understand pain when there is no obvious explanation
The major myths about massage therapy are:
- Massage increases circulation. Probably not… and definitely not as much as a little exercise.
- “Tightness” matters. The three most common words in massage therapy — “you’re really tight” — are pointless.
- Massage detoxifies. It’s actually the opposite, if anything.
- Massage patients need to drink extra water to “flush” the toxins liberated by massage.
- Massage treats soreness after exercise. Studies have shown only slight effects.
- Massage reduces inflammation. An extremely popular belief based mainly on a single seriously flawed study.
- Fascia matters. The biggest fad in the history of the industry.
- The psoas muscle is a big deal. The most overhyped single muscle.
- Massage stimulates endorphins (natural opioid) and reduces cortisol (stress hormone). They do not.
- “Trigger points” are evidence-based.
- Massage therapists have spooky palpation skills. No, it’s just ordinary expertise… and misleading.
The complete list of dubious ideas in massage therapy is much larger. See my general massage science article. Or you can listen to me talk about it for an hour (interview).
And massage is still awesome! It’s important to understand the myths, but there’s more to massage. Are you an ethical, progressive, science-loving massage therapist? Is all this debunking causing a crisis of faith in your profession? This one’s for you: Reassurance for Massage Therapists: How ethical, progressive, science-respecting massage therapists can thrive in a profession badly polluted with nonsense.
What’s new in this article?
Six updates have been logged for this article since publication (2012). All PainScience.com updates are logged to show a long term commitment to quality, accuracy, and currency. more
Like good footnotes, update logging sets PainScience.com apart from most other health websites and blogs. It’s fine print, but important fine print, in the same spirit of transparency as the editing history available for Wikipedia pages.
I log any change to articles that might be of interest to a keen reader. Complete update logging started in 2016. Prior to that, I only logged major updates for the most popular and controversial articles.
See the What’s New? page for updates to all recent site updates.
Nov 13, 2020 — Updated audio version of the article to incorporate recent significant changes.
2020 — Made a significant correction to my summary of Rathbone et al. I had not noticed an important distinction between intra- inter-rater reliability, which led to more errors in my reporting. The correction also made it possible to make the point of the section more clearly and cleanly.
2017 — More perspective (and citations) added to the discussion of the state of the evidence about trigger point treatment.
2017 — Science update — new citation for the diagnostic reliability question. I added a thorough discussion of Rathbone, and made tweaks to the bottom line:
2016 — Added a summary of major points to the beginning of the article. Added the story of my evolving views of the subject.
Many minor unlogged updates.
2012 — Publication.
- Quintner JL, Bove GM, Cohen ML. A critical evaluation of the trigger point phenomenon. Rheumatology (Oxford). 2015 Mar;54(3):392–9. PubMed #25477053 ❐ This is the main example of trigger point skepticism in a peer-reviewed journal — it’s important, but it’s also the only one. I provide a complete summary of the public debate, with all relevant references, in a separate article: Trigger Points on Trial.
- I was a Registered Massage Therapist with a busy practice in Vancouver, Canada, from 2000–2010, RIP. After that, science journalism and this website took over my career and they remain my sole focus today. See my bio.
- “The first principle is that you must not fool yourself & you are the easiest person to fool.” (Feynman)
I take it as an article of faith that I misunderstood the meaning of many of my clinical experiences. I was never an over-confident therapist. I was prone to earnest self-deprecation and making a virtue of candid confessions of my limitations. And yet I wrote an entire book based more or less on my experience. Experiences like the “ultimate trigger point treatment anecdote” described below.
The colorful history of medicine and quackery is overflowing with people who “swore by” treatments that were bizarre and dangerous. Bloodletting was popular almost until the 20th century, despite being relentlessly harmful. Some of the most lethal “cures” in history were inspired by the discovery of radiation. People happily drank metals like mercury and silver. Even drinking urine had near fad status for a while! They tried to purge disease with sulfuric acid, and stimulate their vitality (and virility) with powerful electric shocks. Women were sold Lysol as a douche … and women actually went along with it for a while. Voluntary lobotomy may be the craziest of them all: it was a popular treatment for all kinds of psychiatric disorders, and at least fifty thousand people volunteered to have their brains lanced.
All of these terrible treatments, and many more obscure examples, had many fans and enthusiastic testimonials. People paid for them, believed in them, loved them, swore by them — that is how misleading testimonials can be. People believe what they want to believe.
- No one will ever discover the one true cause of chronic pain the way Dr. John Snow proved with a simple test that cholera was coming from a polluted well: he removed the pump handle, and the cholera stopped. Simple, no? Goodness, no, not even that was straightforward: to prove that cholera wasn’t in the water, some smartass skeptic drank a glass of the stuff … and got away with it, because he just happened to be immune, a rather unlikely coincidence. So he was convinced of an utterly wrong answer by experience — and then he convinced a lot of other people at the time, derailing the relatively simple truth. If it’s that difficult to sort out something like “polluted wells cause disease,” sometimes I fear that we don’t really have a fighting chance with problems like chronic pain.
- Ingraham. Does Fascia Matter? A detailed critical analysis of the clinical relevance of fascia science and fascia properties. ❐ PainScience.com. 30429 words. Many massage therapists are selling “fascial therapy” to patients. The main idea is that fascia — sheets of tough connective tissue found throughout the body — can get tight and restricting, and needs to be “released” by pulling on it. Fascia science is considered an exciting frontier in manual therapy. Unfortunately, although some fascia biology is interesting, the stuff does not seem to have any properties that are actually relevant to healing and therapy. Key examples of fascia research either fail to support fascial therapy or actually undermine it. Enthusiasm about fascia seems to be an unjustified fad.
- FMperplex.com [Internet]. Wolfe F. Travell, Simons and Cargo Cult Science; 2013 Feb 19 [cited 17 Oct 27].
- Co-opted or corrupted evidence-based medicine is a familiar problem, and I’ve written about it for years: see Why “Science”-Based Instead of “Evidence”-Based? For a definition of pseudoevidence-based-medicine, Wolfe quotes Smith: PEBM is medicine in which “falsehoods result from corrupted evidence” or “evidence that has been suppressed, contrived from purposely biased science, or that has been manipulated and/or falsified, then published.”
- Unsurprisingly, when I first published this, I got some questions from customers wondering if my book is still worthwhile. For instance, one massage therapist reader asked, “Would you say that trigger point techniques are still useful even if we have to concede that the theory may be wrong and the underlying mechanism is unknown? Or are you challenging it to the core?” Yes, certainly the book is still worthwhile — I’m improving and correcting it, not burning it. This would be a rather different article if I actually thought that all of trigger point therapy needed to be chucked. My challenge to the idea of trigger points will be mainly an academic exercise, with mostly subtle clinical implications. I don’t want to diminish my point too much by saying that — details really do matter, the correctness of the underlying theory matters — but it is a matter of details. The main change in my book is the theory and the science, and not the practical recommendations. Agnosticism about technique has always been baked right into the book anyway. I’ve never seen much reason to believe any particular technique was superior in the first place, so I never really committed to any school of thought that I now regret or have to change.
- If I had a buck for every therapist I’ve ever heard justify brutally intense massage because they wanted to “break the adhesions” in trigger points, which doesn’t even make sense if we accept the conventional hypothesis…
- Ingraham. Pain is Weird: Pain science reveals a volatile, misleading sensation that is often more than just a symptom, and sometimes worse than whatever started it. ❐ PainScience.com. 14632 words. Modern pain science shows that pain is a volatile, complex sensation that is thoroughly tuned by the brain and often overprotectively exaggerated, so much so that sensitization often becomes more serious and chronic than the original problem. All of this has complicated “all in your head” implications: if the brain controls all pain, does that mean that we can think pain away? Probably not, but we do have some “neurological leverage” of great value — we can influence pain, if we understand it.
- Andersen H, Ge HY, Arendt-Nielsen L, Danneskiold-Samsøe B, Graven-Nielsen T. Increased trapezius pain sensitivity is not associated with increased tissue hardness. J Pain. 2010 May;11(5):491–9. PubMed #20015697 ❐
- Wolfe F, Simons DG, Fricton J, et al. The fibromyalgia and myofascial pain syndromes: a preliminary study of tender points and trigger points in persons with fibromyalgia, myofascial pain syndrome and no disease. J Rheumatol. 1992 Jun;19(6):944–51. PubMed #1404132 ❐
Four experts on myofascial pain syndrome (MFP) performed trigger point examinations and 4 experts on fibromyalgia performed tender point examinations on 3 groups of subjects (7 patients with fibromyalgia, 8 with MFP, and 8 healthy persons) while blinded as to diagnosis. Local tenderness was common in both disease groups (65-82%), but was elicited in a greater proportion of MFP experts' examinations (82%). Active trigger points were found in about 18% of examinations of patients with fibromyalgia and MFP, but latent trigger points were rare in all groups. A more liberal definition of trigger point, however, resulted in a 38 and 23% positive rate among patients with fibromyalgia and MFP, respectively. Taut muscle bands and muscle twitches were common (50 and 30%, respectively) and noted equally in all 3 diagnostic groups. Problems with reliability were identified for taut bands, muscle twitch, and active trigger points. Our data are exploratory and tentative, but suggest that attention to definition and reliability are required to advance our knowledge of these common syndromes.
- Sciotti VM, Mittak VL, DiMarco L, et al. Clinical precision of myofascial trigger point location in the trapezius muscle. Pain. 2001 Sep;93(3):259–66. PubMed #11514085 ❐
One of the earlier studies of trigger point diagnostic reliability. It proceeds based on the assumption that interrater reliability had already been established (debatable at the time, and debated ever since). The goal here was to test the precision of trigger point detection. They tested four clinicians that “trained extensively together prior to the study,” examining 20 subjects. They used a special camera system to record the exact location of each putative trigger point “without providing feedback to subsequent clinicians,” and the data was analyzed after all assessments were completed. Any two of the four testers had more than 80% agreement with each other about location, with high precision as well, accurate to within 6.5-7.5mmm, “the physical dimensions of the clinician's own fingertips.” They concluded that “two trained examiners can reliably localize latent TrPs.”
- Lucas N, Macaskill P, Irwig L, Moran R, Bogduk N. Reliability of physical examination for diagnosis of myofascial trigger points: a systematic review of the literature. Clinical Journal of Pain. 2009 Jan;25(1):80–9. PubMed #19158550 ❐
- Myburgh C, Larsen AH, Hartvigsen J. A systematic, critical review of manual palpation for identifying myofascial trigger points: evidence and clinical significance. Arch Phys Med Rehabil. 2008 Jun;89(6):1169–76. PubMed #18503816 ❐
- Rathbone AT, Grosman-Rimon L, Kumbhare DA. Interrater Agreement of Manual Palpation for Identification of Myofascial Trigger Points: A Systematic Review and Meta-Analysis. Clin J Pain. 2017 Aug;33(8):715–729. PubMed #28098584 ❐
- Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977 Mar;33(1):159–74. PubMed #843571 ❐
Landis and Koch suggested labels for ranges of Cohen’s Kappa values, describing 𝛋 = 0–0.20 as slight, 0.21–0.40 as fair, 0.41–0.60 as moderate, 0.61–0.80 as substantial, and 0.81–1 as almost perfect . These labels were just expert opinion, and are controversial, but have been widely cited and used ever since, because they are imprecise enough to be “good enough” for many purposes.
- Theinvisiblegorilla.com [Internet]. Chabris C, Simons D. The Invisible Gorilla; 1999 [cited 20 May 13].
Description and video of a classic mind-blowing psychology experiment that demonstrated “inattentional blindness” — such as not noticing a gorilla walk through a group of people you’re watching.
Chabris & Simons book is excellent read: see The Invisible Gorilla.
Special pleading is an informal fallacy: claiming an exception to a general trend or principle without actually establishing that it is, either using a thin rationalization or even just using the exception as evidence for itself (“the rules don’t apply to my claim because my claim is an exception to the rule”).
- French SD, Green S, Forbes A. Reliability of chiropractic methods commonly used to detect manipulable lesions in patients with chronic low-back pain. J Manipulative Physiol Ther. 2000 May;23(4):231–8. PubMed #10820295 ❐
I do enjoy reliability studies, and this is one of my favourites. Three chiropractors were given twenty patients with chronic low back pain to assess, using a complete range of common chiropractic diagnostic techniques, the works. Incredibly, assessing only a handful of lumbar joints, the chiropractors agreed which joints needed adjustment only about a quarter of the time (just barely better than guessing). That’s an oversimplification, but true in spirit: they couldn’t agree on much, and researchers concluded that all of these chiropractic diagnostic procedures “should not be seen … to provide reliable information concerning where to direct a manipulative procedure.”
- Gerwin RD, Shannon S, Hong CZ, Hubbard D, Gevirtz R. Interrater reliability in myofascial trigger point examination. Pain. 1997 Jan;69(1-2):65–73. PubMed #9060014 ❐
This paper describes a failed initial attempt to confirm that the diagnosis of trigger points is reliable, and then goes on to report on greater success with practitioners who were more thoroughly trained. Unsurprisingly, the authors conclude that some diagnostic signs are more difficult to reliably detect than others, and some trigger points are harder to diagnose in some muscles than others.
- A few of the more interesting examples, all with notes: Hanten 2000, Aguilera 2009, Hodgson 2006, Gemmell 2008, Gulick 2011, Cagnie 2013, Morikawa 2017.
- Aguilera FJ, Martín DP, Masanet RA, et al. Immediate effect of ultrasound and ischemic compression techniques for the treatment of trapezius latent myofascial trigger points in healthy subjects a randomized controlled study. J Manipulative Physiol Ther. 2009 Sep;32(7):515–20. PubMed #19748402 ❐
- A couple centuries and counting with nothing but evidence of no effect. I reviewed homeopathy pretty thoroughly for my homeopathic arnica article.
- “Straight” meaning the original, subluxation-based spinal manipulation as a replacement for internal medicine — a little over a century and counting with no evidence for that. Because it’s pre-scientific nonsense. See Organ Health Does Not Depend on Spinal Nerves!.
- Travell and Simons may not have been perfect. Travell in particular may have succumbed to guru-ism, with all of its mental blinkers. But both Travell and Simons were extensively on the record encouraging research, and not just in general up-with-science way: they made many specific suggestions, in ink, about which hypotheses and assumptions needed to be checked and why. Whether they would have actually been able to accept evidence that challenged their hopes and beliefs is unknowable, but that is no way to judge the matter. Many scientists have ended their careers unable to accept new evidence.
- This is the cart-before-horse problem in alternative medicine. “We need some science to prove how treatment modality X works!” No! No no no! That is bass-ackwards. It’s a terrible inspiration for doing science, guaranteed to dial confirmation bias up to 11.
- A faddishly vibrant area of research which doesn’t even achieve clinical relevance, let alone demonstrate that any patients are actually helped by any therapeutic method informed by fascia science. See Does Fascia Matter?
- Ramos GA, Arliani GG, Astur DC, et al. Rehabilitation of hamstring muscle injuries: a literature review. Rev Bras Ortop. 2017;52(1):11–16. PubMed #28194375 ❐ PainSci #52750 ❐
- Loxton D, Prothero DR. Abominable science! Origins of the Yeti, Nessie, and other famous cryptids. Columbia University Press; 2012. I challenge any sane person to read up on the history of Bigfoot without coming to the conclusion that the whole business is utter nonsense.
- Travell J, Simons D, Simons L. Myofascial Pain and Dysfunction: The Trigger Point Manual. 2nd ed. Lippincott, Williams & Wilkins; 1999.
- Mense S, Simons DG, Russell IJ. Muscle pain: understanding its nature, diagnosis and treatment. 1st hardcover ed. Lippincott Williams & Wilkins; 2000.
- To answer a likely question: no, the contractility of fascia does not solve the puzzle. Yes, connective tissue is marginally contractile (Schleip 2006), but the phenomenon is wholly inadequate — too slight, too gradual — to plausibly power trigger points of the same character as that which allegedly exist in muscle bellies.
- Muscle Pain, p240.
Our current understanding of trigger points results from the convergence of two independent lines of investigation, one electrodiagnostic and the other histopathologic. Sitting together the lessons from each leads to an integrated hypothesis can explain the nature of trigger points. It is now becoming clear that the region we are accustomed to calling a trigger point or tender nodule is a cluster of numerous microscopic loci of intense abnormality that are scattered throughout the trigger point or nodule. This would make myofascial pain caused by trigger points a true neuromuscular disease.
- The reason many fish walk or fly must be clarified, but must be different from swimming … .
- The big red books acknowledge and describe nonmyofascial trigger points in some detail, but this only deepens the chasm. No effort was made to actually account for them, or integrate them into their integrated hypothesis of trigger points.
- Quintner JL, Cohen ML. Referred pain of peripheral nerve origin: an alternative to the "myofascial pain" construct. Clin J Pain. 1994 Sep;10(3):243–51. PubMed #7833584 ❐ PainSci #54775 ❐
The construct of MPS, as proposed to explain chronic, deep, aching, poorly localized pain, not only lacks internal and external validity but also is epistemologically unsound. The emphasis on the primacy of the TrP phenomenon has directed attention away from other possible explanations. By contrast, there are anatomical and physiological grounds to suggest that the phenomenon of the TrP … is better understood as a region of secondary hyperalgesia of peripheral nerve origin.