Evidence for the role of psychological factors in abnormal paraspinal activity in patients with chronic low back pain

Objectives: The aim of this study was to investigate the role of physical and psychological factors on changes in surface electromyography [sEMG] during static and dynamic activity of the lumbar paraspinal muscles in a group of chronic low back pain [CLBP] patients following a pain management program. Methods: Surface electromyographic recordings of the lumbar paraspinal muscle activity of 36 patients attending a pain management program were made during static and dynamic activity prior to the program and immediately afterwards. A measure of abnormality, the Flexion Relaxation Ratio [FRR] was calculated to observe the effect on the Flexion Relaxation Phenomenon [FRP]. Patients were assessed for current back pain and on a range of physical and psychological variables. Results: There were no significant correlations between current pain or disability and the FRRs. Significant correlations were identified between fear avoidance beliefs and low FRRs prior to the Pain Management Program. Following the program, significant correlations were identified between reductions in fear avoidance beliefs, increases in pain self efficacy beliefs and increased FRRs on movement. No such relationships were observed between sEMG measures and changes in range of movement, pain report or disability. Conclusion: The results of this study suggest that the absence or reduction of the FRP, measured by the FRR, in patients with CLBP is influenced by fear of injury and low self efficacy beliefs and changes in FRRs were independent of the range of motion and pain report in the group studied. Therapists should consider the role of psychological factors in the development and resolution of abnormal recruitment in patients with low back pain.