The role of anticipation and fear of pain in the persistence of avoidance behavior in patients with chronic low back pain.

STUDY DESIGN A correlative design using stepwise regression analysis. OBJECTIVE To explore the variation in spinal isometric strength that can be accounted for by anticipation of pain, sensory perception of pain, functional disability belief, and the fear-avoidance belief in chronic low back pain patients. SUMMARY OF THE BACKGROUND DATA Several biobehavioral factors contribute to the persistence of pain behavior in chronic patients. Recent studies suggest a need to explore the relation between reduced physical performance and the sensory and cognitive perception of pain. METHODS Sixty-three patients with chronic low back pain 20 to 56 years of age participated in this study. Visual Analogs Scales, the Fear-Avoidance Belief questionnaire, and the Disability Belief questionnaire were used to measure the sensory and cognitive dimensions of pain. Spinal isometric strength was measured by the Medx lumbar extension machine. RESULTS Analysis of variance and the stepwise regression analysis demonstrated that anticipation of pain and the fear-avoidance belief about physical activity significantly predicted variation in the spinal isometric strength deficit P < 0. 001. True pain experienced during the testing and answers to the Disability Belief questionnaire were not related. CONCLUSION The results of this study strongly support the hypothesis that spinal physical capacity in chronicity is not explained solely by the sensory perception of pain. The anticipation of pain and the fear-avoidance belief about physical activities were the strongest predictors of the variation in physical performance.