Physical activity and low back pain: the role of subgroups based on the avoidance-endurance model.

Abstract

This study examines the relationship between low back pain, disability and fatigue and overt physical activity with respect to fear-avoidance and endurance-related subgroups. 49 patients completed questionnaires (Pain, Disability, Fatigue, Depression, Pain-responses pattern) 6 months after lumbar disc surgery and underwent an 8-hour accelerometer assessment measuring overall physical activity (PAL), constant strain postures (CSP), standing time (ST) and lying time (LT). Four subgroups, representing patterns of distress-endurance (DER), eustress-endurance (EER), fear-avoidance (FAR) and adaptive responses (AR) due to the avoidance-endurance model of pain-regulation were investigated. Multivariate analyses of covariance revealed significantly higher pain, disability and fatigue in FAR compared to AR patients and, as expected lower PAL and CSP in FAR than in endurance patients. Both endurance groups revealed higher pain accompanied by higher accelerometer-based physical activity (PAL, CSP) than AR and FAR patients. Most of the subgroup differences displayed moderate to high effect sizes. The results indicate different pathways to chronic pain and disability with physical underuse in FAR patients and overuse/overload in endurance patients suggesting the need for individually targeted cognitive-behavioral treatments in the maladaptive groups. Implications for Rehabilitation Improving the return to a normal physical activity level is an important goal for the rehabilitation of patients after lumbar disc surgery. Different pathways to chronic pain and disability with physical underuse in fear-avoidance patients and overuse in endurance patients should be considered. Different pain-related pain response pattern, based on the avoidance-endurance model, indicate the need for individual targeting of rehabilitation programs.