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Contradictory feedback can lead to worker neck and back pain: study


Photo: Christian Horz/iStockphoto

Columbus, OH — Cognitive dissonance “may be a previously unidentified risk factor” for neck and low-back pain among workers who perform lifting and lowering tasks, results of a recent study show.

Researchers at Ohio State University asked 17 participants, ages 19 to 44, to perform a precision lowering task in which they placed a lightweight box within a square on a surface that was moved left, right, up and down. During the first of two 45-minute lifting and lowering trials, the participants were given nearly all positive feedback. During the second trial, the researchers told them they were performing the task unsatisfactorily.

Wearable sensors and motion-capture technology were used to detect peak spinal loads in the neck and low back: both compression of vertebrae and vertebral movement – or shear – from side to side (lateral) and forward and back (A/P).

After receiving the conflicting feedback – which created cognitive dissonance – the participants experienced increased loads on vertebrae in their neck and low back during a third lifting and lowering session. On average, peak spinal loads in the neck were 19.3% higher in lateral shear and 11.1% in compression during the negative-feedback session compared with baseline measures. Peak loads on the low back were 2.2% higher in shear and 1.7% higher in compression during the third session.

A rise in cognitive dissonance was identified by changes in participants’ blood pressure and heart rate variability, along with two questionnaire responses assessing discomfort levels and a positive or negative effect – feeling strong and inspired or distressed and ashamed.

The researchers note that the findings could have implications for risk prevention in the workplace.

“This increased spine loading occurred under just one condition with a fairly light load,” senior study author William Marras, executive director of the Spine Research Institute at OSU, said a report published by Ohio State News. “You can imagine what this would be like with more complex tasks or higher loads. A small percentage of load is no big deal for one time. But think about when you’re working day in and day out, and you’re in a job where you’re doing this 40 hours a week – that could be significant and be the difference between a disorder and not having a disorder.”

The study was published online in the journal Ergonomics.

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