Chronic back pain slowed how quickly people sensed their back, while their hands kept pace

Show someone who has lived with low back pain for years a picture of a rotated hand and ask whether it's a left or a right, and they answer about as quickly as anyone else. Show them a whole body twisting through the trunk and ask the same kind of question, and something slows down. That is the finding of a small comparative study from the University Hospital of Poitiers, published in the September issue of Archives of Rehabilitation Research and Clinical Translation (Teillet and colleagues, 2026).

Nineteen adults whose low back pain had lasted more than three months, eleven of them women, average age about 46, were matched by age and sex with nineteen people who had never had back pain. Everyone did two short computer tasks in random order. In the first, 128 images showed an avatar in four large trunk movements (bending forward, rotating, a kickboxing movement and a capoeira movement) seen from the front, the back and either side, with a red dot on one arm or leg; the question was whether the dot sat on the left or the right of the body. In the second, 64 images of a hand, rotated anywhere from 40 to 160 degrees, asked the plainer question: left hand or right hand?

Tasks like these are called laterality judgments, and they work because most people can't answer them from the picture alone. You quietly rotate your own body, or your own hand, in imagination until it lines up with the image, and the time that takes is a window onto the body schema, the working map the nervous system uses to plan movement. The same family of task sits at the start of graded motor imagery.

On the trunk task, the pain group was slower by roughly a quarter of a second per image on average, and the difference held up. On the hand task the groups did not reliably differ; the pain group was a touch slower there too, but not by enough to separate from chance. Accuracy was high for everyone on both tasks, and on the trunk images the pain group was, if anything, slightly more accurate than the controls. The delay also had no clear relationship with pain. Not with average pain over the week, not with the pain people expected from those movements, not with how much of the body they shaded as painful.

The authors read this carefully. An accurate answer given more slowly suggests the map of the back is intact; it is costly to consult. Their proposed mechanism is that people move a painful region less, often from fear of hurting it again, and a region that moves less gets updated less, as seen when a limb is immobilised. They suggest location specific tasks as a cheap way to detect these changes, and they say plainly that whether training with them helps chronic low back pain remains to be established.

The limits are real. Nineteen people per group, one hospital, one sitting. This is a snapshot, so it cannot say whether the slowing comes before the pain, after it, or grows alongside it.

Approaching the back indirectly

People with long back histories can almost always do the movement I suggest. What I notice is the moment before it: a small bracing, a held breath, the eyes drifting up as if the instructions were written on the ceiling. I can't say that pause is the same thing as a quarter second on a laterality task, but it looks familiar. You haven't lost movement. You've lost trust that movement will help.

If the slowing lives around the back rather than everywhere, a general relaxation session may pass it by. In an Awareness Through Movement® lesson, the guided group lessons of the Feldenkrais Method®, the lower back is rarely asked to move first. We come to it through places that still move easily: the knees tilting while lying down, the head rolling, one hand pressing lightly into the floor. Soon the pelvis and lower spine are moving as a consequence of something else, small and many times, with attention on how it feels rather than on getting it done. And because the slowing did not follow pain, there is little reason to wait for the pain to settle before starting to sense again. The Feldypedia entry on chronic lower back pain has the wider picture.

For clinicians, the useful detail is dose. The graded motor imagery programmes the authors mention run about 10 to 15 minutes, several times a day, for weeks: short, frequent, low threat time with the region itself. That is the rhythm the Feldy online movement program is built around, audio guided so attention stays on the body rather than a screen, and it sits alongside the plan a physiotherapist gives rather than in place of it. Our look at imagined movement for spinal pain found the certainty still very low, so whether this kind of practice refreshes the map is a direction to watch, not a protocol.

A quarter of a second is too short for anyone to notice. Repeated every time the back is asked to turn, it may be long enough to become a habit of hesitation. The hopeful half of the finding is the accuracy: the map of the back was intact, only slow to consult. And slowness, unlike damage, is something a nervous system may learn its way through.