The trouble with demonizing trivial physical stresses

In 2018, Yamato et al studied the effect of backpacks on back pain in kids, and found… nothing.

There is no convincing evidence that aspects of schoolbag use increase the risk of back pain in children and adolescents.

The concern about packs is the old school version of the trendier anxiety about “text neck” (see Richards, Damasceno), just with backs and backpacks instead of necks and smartphones.

Hopefully evidence like this can undermine overconfidence in the importance of trivial physical stresses, posture, and biomechanics in back pain. Hopefully it can inspire us to put more emphasis on the psychosocial factors and subtler biological vulnerabilities that spinal pain is probably much more sensitive to.

Things we overestimate as causes

It may seem like “common sense” that physical stresses must cause back pain. For instance, it might seem like obesity has to be responsible for the epidemic of back pain, surely. And yet it clearly isn’t.

And someone said to me, while doubting the findings of the backpack study, that awkward lifting technique “has to be” responsible for some back pain. Actually, not necessarily. We all have to beware of overconfident talk like “has to be” when it comes to the causes of chronic pain, because there are a lot of very non-obvious factors in chronic pain. It rarely works out to assign most of the blame to any one factor.

Another one: excessive sitting must be a risk factor for back pain, right? Surely that? Probably not, no. I had to correct my own common sense on this topic a while back. See the first section of my chairs treatise: “Sitting a lot is not—repeat, NOT—a risk factor for low back pain.”

The failures of common sense are legion, especially in the life sciences, where the complexity is generally much greater than our paltry powers of inference. I’ll focus on that in another post soon. I’ve been compiling a list of examples of failed common sense.

If not these stresses, then what?

There are undoubtedly some mechanical stress factors in back and neck pain, but our complex vulnerabilities to those stresses is probably the real story, factors like sleep deprivation, a subtle pathology like hypermobility, a vitamin deficiency, or increased systemic inflammation from aging and metabolic syndrome, to name a few fairly straightforward examples.

And even just the perception of back fragility and pessimism make us more vulnerable to persistent pain, and maybe that is more of a problem than all kinds of trivial physical stresses put together. That fearful fire has been fanned by therapists selling “fixes” for mechanical problems with exaggerated clinical importance based on “common sense” instead of evidence.

Demonizing trivial physical stresses is incorrect and wrong: it sends the nocebic & incorrect message that our bodies are fragile, especially our spines. It’s a message that people embrace all too easily, to their detriment.