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A kooky “scientific” study of massage

 •  • by Paul Ingraham
Weekly nuggets of pain science news and insight, usually 100-300 words, with the occasional longer post. The blog is the “director’s commentary” on the core content of a library of major articles and books about common painful problems and popular treatments. See the blog archives or updates for the whole site.

I have posted four substantive updates to my new article about the effect of massage on circulation since publication on May 2, a couple of them driven by ongoing exploration of the scientific literature, including one particularly good quality paper. Good enough to change my mind some: it persuaded me that the evidence on this topic may be closer to “inadequate” than “negative,” an important distinction.

So that’s nice. And distressingly rare. Good science is getting harder to find.

For contrast, I also read an especially bizarre paper that is never going to be cited on except as an example of junk science. I spent quite a bit of time wrapping my head around it, and I don’t want that work to go to waste. So how about a little rant about it here?

“Connective tissue reflex massage for type 2 diabetic patients with peripheral arterial disease: randomized controlled trial”
Castro-Sánchez et al. Evid Based Complement Alternat Med. Volume 2011, Number , 804321. 2011.

At first glance it all seemed fine

This paper has plenty of superficial credibility. It looks like a straightforward good-news study of massage improving circulation in diabetics, and that is why I invested too much time in it: it fooled me for a while.

The type of massage they studied — “connective tissue massage” — is not obviously suspicious. It’s not until you get into the text that the alarm bells start to go off. It’s really weird stuff.

There’s an even more glaring problem: trying to fix impaired circulation in diabetics is a delusional goal. Circulation in those patients is impaired by some dire neurological and structural dysfunction. There is no hope of changing that with any kind of massage. Unfortunately, this didn’t occur to me at first, or I could have aborted.

So the hypothesis tested by these researchers is just about as implausible as it gets without involving auras or aliens, and that low plausibility alone would kill it. It is not widely appreciated just how much low plausibility undermines allegedly positive study results. ?Regina Nuzzo: “The more implausible the hypothesis — telepathy, aliens, homeopathy — the greater the chance that an exciting finding is a false alarm, no matter what the P value is.” See also Pandolfi and Carreras.

So what’s so strange about the massage technique?

“Connective tissue massage” turns out to be “massaging along reflex lines on areas of the skin connected (at a distance) with deep tissue and internal organs, known as Head zones.” This is a strange, unvalidated, old massage modality from the 70s, based on some extraordinary claims, a deeply weird mixture of assumptions and ignorance. It reeks of an old school “pet theory.”

More odd details, mostly to emphasize just how far out in left field this method is:

The massage protocol consisted of reflex-massaging the skin with the third and fourth fingertips to stretch the subcutaneous connective tissue to the maximum. The therapist flexes the elbow away from the body, rotates the shoulder internally and applies a light radial twist to the wrist. The patient should experience the massage as a ‘switching-off‘ feeling.

Oh, the sh*t massage therapists say!

It goes on and gets stranger still: an extremely detailed, specific, and kooky massage protocol that has exactly nothing to do with normal massage. It’s purpose is to generate reflex effects throughout the body by manipulating the skin, making it like a cousin of reflexology. There’s nothing silly about the general idea that touch might have interesting effects, but the baroque specificity of this method is hilariously overconfident.

Junk science

Would I accept the results if it weren’t for the weird technique and the implausible therapeutic goal? No, because there are still more concerns here. The authors are obviously fans of connective tissue massage, and almost certainly motivated by the desire to prove that it works (super high risk of bias). Their experimental design seems impressive, but it is also easily abused: lots of technical measures, which provide ample opportunities for P-hacking. Even so, their technically “positive” results were only just barely so, but (of course!) summarized as a simple win in the abstract:

Connective tissue massage improves blood circulation in the lower limbs of type 2 diabetic patients.

This is a hallmark of pseudoscience: the actual data is complex mess that says “meh, I think?” while the authors declare victory.

I do not trust this study any farther than I can throw a paper airplane into a high wind. Even if I did, it wouldn’t be relevant to the kind of massage therapy generally available to consumers.

This is some of the junkiest science I’ve ever been a bit slow to spot. Total time invested so far? About six hours by the end of this post. Return on investment? Not exactly clear, but I have had some good laughs at the least.

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