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This is my second post in as many days about screwing up.
This entire old article of mine, Running on Pavement is Risky, is based on a common-sensical, “obvious” premise with a really glaring citation-needed problem. Is there any direct scientific evidence that running on hard surfaces is actually a problem? Has anyone ever gotten big groups of people to run for a long time on different surfaces, measuring injury rates in both groups? Noooooo! Amazingly, it’s a completely untested idea, as others have already explained. It’s a serious weakness in the article, because “what can be asserted without evidence can be dismissed without evidence” (Hitchen’s Razor). So I will be revising the article ASAP.
Meanwhile, it’s not like it’s crazy to think that hard surface running might be risky. It’s a perfectly reasonable hypothesis, and there is some indirect evidence both supporting and undermining it. So, while this warning remains in place, please treat the rest of the article like it’s the case against hard surface running. I’ll be updating it to reflect both sides of that controversy.
It’s hard to convince most people that anecdotes about medical treatments are unreliable. Maybe this embarrassing personal example will help: a story about how wrong these kinds of stories can be, an anecdote about the trouble with anecdotes.
I thought I had successsfully self-treated a problem. I won’t say what problem or treatment, because I don’t want to get caught up in the politics of the particulars. I had a symptom, and I did something for it; let’s call that attempt “X.”
It seemed like X made a difference, and — spoiler alert — I was probably wrong. How I got it wrong is what’s worth telling.
Before you can fall, you have to climb. I started to think optimistically about treatment X. I considered its implications for my website, for my readers, for my own life. I got my hopes up. I started to pet my theory. I knew it was speculative, and I didn’t get too carried away, but I was definitely starting to take it seriously. I did this for more a day or two.
And then I realized my mistake.
I was enjoying my idea so much that I had missed two other oddball variables — let’s call them Y and Z — that aren’t normally a part of my equation.
Y and Z were a bit far out in left field, and it’s just a bit of luck that I noticed them out there. I didn’t think my way to them. The only intelligence involved was in recognizing their significance. Something irrelevant made me notice Y, which made me wonder if I was missing anything else, which led me to Z, which led me to palm my face, because I realized that Y and Z could both independently explain my “success” with X. At the very least, Y and Z made it impossible to actually draw any conclusions. They broke the deal. Y and Z woke me up from my X dream.
In five minutes I went from thinking I was really onto something to thinking, “What was I thinking?”
It’s surprising that this would happen to me, of all people.
I’ve been immersed in this kind of problem and subject matter for more than 15 years now, constantly trying to understand why people hurt, what helps and what doesn’t, and how we get it wrong. I’m a professional debunker, mythbuster, and truth seeker in the wilds of musculoskeletal medicine. And I came this close to missing two critical confounding variables, either one of which would have nuked an otherwise promising hypothesis.
And I almost blogged about it. 😱
But instead I’m writing this…because I realized just in time. By a fluke, basically.
If I can make this mistake, how easy is it for someone unschooled in the ways of skepticism to fall into the same trap? Someone who has no idea what constitutes “critical thinking,” let alone in a medical context? Who doesn’t know the history of bizarre medical beliefs? Someone who can’t define a single logical fallacy and wouldn’t know a cognitive distortion if it bit them on the parietal lobe? Someone with a life?
Most people who tell treatment-success stories have only a single experience to draw on and know nothing else about that problem or the many other possible explanations for their relief (pain science is vast and strange).
This is why I can’t take it seriously when people tell me what they think works based on their personal experience. (Or even their professional experience.) I can’t take myself seriously, which is actually a central tenet of skepticism. Richard Feynman: “The first principle is that you must not fool yourself, and you are the easiest person to fool.”
This story will not dent the overconfidence of people who believe they have experienced dramatic treatment successes.
When stubborn and serious problems appear to be cured within a few hour or days of receiving a new treatment, people will weld the two things together in their minds — and they are understandably irritated by any attempt to dismiss their story as an unreliable anecdote. Sadly, it is still an unreliable anecdote — not necessarily wrong, but still unreliable.
I tackle this sensitive topic in more detail in The Power of Barking: A silly metaphor for a serious point about correlation, causation, and how we decide what treatments work.
I’ve published three new indexes to PainScience.com articles in different subject categories:
These new reading guides are the start of a hard push towards much clearer site structure based on the topics that readers care about.
Most traffic to this site is driven by search, so readers usually arrive at a page that (hopefully) scratches whatever curiosity itch they had when they fired up the Googles. However, once they are here, they should have a clear sense of “where” they are on the site, and how to get wherever else they want to go. For a decade now, the main menu links have been stupidly about types of content (eg “articles” or “tutorials”). Unfortunately, readers don’t really care about these categories, and (worse) they don’t even have a sense of the difference between “articles” and “tutorials”.
Readers care about topics… and so that is what you’ll see in the main menu of PainScience.com in the future. These new subject-based indexes are a first step in that direction.
Fresh science! New review of 17 “mostly low quality“ studies of the relationship between leg injuries and movement quality shows “inconsistent evidence.” In other words, we have no idea if we can tell who’s going to get leghurt based on screening people for quality-of-movement trouble, e.g. Functional Movement Screen™ (FMS).
I’m always torn about how to interpret these garbage-in, garbage-out reviews: they’re officially inconclusive, because they are obviously reviewing studies that just weren’t designed to answer the damn question. But realistically… they are really just totally damning, because if a bunch of high-bias-risk studies can’t demonstrate the link the researchers are undoubtedly fishing for, then it almost certainly ain’t there. Seriously, how many crappy little studies showing not much do we need before it’s safe to assume that there’s no beef? 4? 7? 17?
I’m still churning out carefully crafted article summaries (as announced in a recent blog post), and still finding it crazy challenging and satisfying. It’s like taking a crash course in my own content. With each one, I feel more certain that these mini articles-within-articles are genuinely a great service to readers and to me: writing them forces me to refine my overall comprehension of a topic.
Today’s example is the topic summary for massage pressure intensity, a surprisingly large one (I think it’s one of the longest “summaries” I’ve written so far). Of course, there’s lot more detail (and citations) in the full article — that’s the whole point, of course. This is 310 words summarizing about eight thousand. 😃
There is no clear justification for painfully intense “deep tissue” massage, and it’s actually hazardous to many patients, but the pressure question is greatly complicated by the fascinating paradox of “good” pain, wildly varied patient pain tolerance and preferences (often timidly repressed), and popular faith in the “no pain, no gain” principle.
“Good pain” is at the heart of the pressure question: a strange, potent sensory paradox that many people actually seek out as the goal of therapy, consciously or unconciously. Either it isn’t literally painful (just intense), or it’s painful but desired anyway because of relief or belief: an actual biological relief or at least the belief that there is one. But it’s important to note that not all satisfying, relieving sensations are genuinely helpful (e.g. scratching a mosquito bite).
“Good pain” is at the heart of the pressure question: a strange, potent sensory paradox that many people seek out as the goal of therapy
“Bad pain” is unpleasant but manageable and probably safe — tolerate it cautiously, to a point.
“Ugly pain” is dangerous both physically and neurologically, causing a “fight or flight” reaction — always avoid it.
People do have clear pressure preferences: they often fire massage therapists who give treatments that are too painful or too fluffy. Pressure that’s fine for you may cause severe pain, emotional distress, “sensory injury” (sensitization) in others, or even physical injury, so pressure should be customized but often isn’t. Brutal massages might be appreciated or even helpful, but most people can’t tell the difference between the kind of pain that might be a necessary part of therapy, and ugly pain that is just abusive and dangerous.
Some possible justifications for painfully intense massage (these aren’t endorsements) include the destruction of motor end plates to “de-activate” trigger points; somatoemotional release (pain often strongly “resonates” with strong emotions like grief); moving tissue fluids; or just creating a strong, novel sensory experiences (which may have many subtle benefits).
You can read the whole thing here: The Pressure Question in Massage Therapy: What’s the right amount of pressure to apply to muscles in massage therapy and self-massage?