Cognitive factors in the performance level of chronic low back pain patients.

An experimental group of 39 chronic low back pain (CLBP) patients and an equal number of controls, matched for age and sex, completed questionnaires of self-concept and performance motivation. SS were also tested on a standardized back-stress physical test carried out with low external information and feedback. The results revealed a strong tendency for CLBP patients to have a negative self-concept, confirming the findings of previous research. Poorer performance of the CLBP patients on the physical test measure of behavioural persistence and on physiological measures were unrelated to reported pain level or to poor physical condition. Compared to the controls, the chronic low back pain group was less able to estimate their physiological level of exertion, being inclined to overrate their actual individual effort. The interaction of a negative self-concept and negative expectations is discussed.