Abstract

Alterations in movement patterns and muscle activities of the lumbar spine are frequently observed in patients with back pain. However there is considerable disagreement as to the underlying causative mechanisms. It is imperative to identify these mechanisms so that clinical management can be rationalized. One popular theory suggests these alterations are "pain-driven". This review presents a systematic appraisal, including effect size calculation of studies utilizing experimentally induced pain and experimental pain relief models to explore this concept. Fifteen studies were identified using MEDLINE and a review of reference lists. Experimentally induced pain did produce changes in electromyography and gait-related kinematics. However these effects were not universal. Experimental pain relief studies produced mixed results for improving maximal muscle function. These methodologies shared similar threats to validity and failed to fully answer the question due to methodological limitations; however possible mechanisms as to the effects of pain are discussed. Further research is required to resolve if pain is indeed the variable driving functional changes in kinematics and muscle functions observed in back pain sufferers, and if it is to what degree. Only then can management strategies begin to be rationalized.