Exposure to physical movement in chronic back pain patients: no evidence for generalization across different movements.

This study investigated whether the effects of exposure to one movement generalize towards another dissimilar movement in patients with low back pain. Thirty-nine patients (11 male, 28 female; mean age=43.49 yrs) were requested to perform two movements twice, i.e. bending forward and straight leg raising. During each of the four trials, baseline pain, expected pain and experienced pain were recorded. Analyses revealed that patients initially overpredicted pain, but after exposure the overprediction was readily corrected. This exposure effect did not generalize towards another dissimilar movement. The above pattern of results was only characteristic for patients reporting a high frequency of catastrophic thinking about pain. Low pain catastrophizers did not overpredict pain. The results are discussed in terms of the view that exposure may be better conceived of as the learning of exceptions to a general rule.