There is a big difference between “poor posture” and “postural stress,” but the distinction seems to be absent from most discussions of posture and ergonomics.
“Poor posture” is body positioning that’s habitual but optional — a behaviour. And it’s mostly a vague bogeyman: hard to define, hard to fix, and hard to causally link to any other kind of pain or injury. Health-conscious people are haunted by the idea that they “should” correct their posture, and many fight a chronic, uncertain, and tedious battle against self-imposed or careless crookedness, primarily as self-defense against common problems like neck pain, headaches, and especially low back pain. If your main issue is unexplained or stubborn aches and pains, worry about and working on posture is not a great investment.
Examples of poor posture:
- “Upper-Crossed Syndrome” (head and shoulders forward, mostly)
- “text neck” — regularly looking down at a smartphone screen
- sharply bending the knees to tuck the feet behind/under the legs of a chair
- side slouching in a chair, an asymmetrical sitting position
Examples of postural stress:
- trying to sleep where it’s impossible to do so without putting your neck in an awkward position, like a plane or car seat
- a cashier whose till is positioned a little too far away, causing chronic reaching
- uncorrected vision problems, forcing routine squinting and awkward head repositioning
- a drywall installer who virtually lives in constant neck extension
- a nurse who must constantly stoop over patients, and perform extremely awkward patient lifts
Neither poor posture nor postural stress is clearly a risk factor for any common pain problem. While some of the more extreme postural stresses can definitely cause trouble — drywalling and neck pain is a classic example — things are much murkier with subtler postural stresses. Example …
Computer display height
This topic came to my attention recently when I discovered that I was probably wrong that a high computer display causes neck pain.
For some reason, many people think they should be looking up at a computer display, and actually go out of their way to lift them up. That always seemed like a bad idea to me. Low displays are less common, but they also always seem like a bad idea to me.
But what “seems” like a bad idea to me is may not actually be correct. Yes, it’s true: common sense is fallible! Even educated guessing. Imagine! And decent evidence (see Paksaichol et al) has shown that people who believe their computer display is in a poor position are not at greater risk for neck pain. That’s not a slam dunk, of course — postural stress isn’t always obvious, and what people “believe” about their display position may not line up all that well with what is actually good or bad. It could be a risk factor without having anything to do with how people perceive the placement … but that’s reaching a bit. Most likely this is just a classic case of failed “common sense.” Common sense fails a lot.