Lumbar extension mobility correlates with postural sway in patients with nonspecific low back pain

Background Nonspecific low back pain (NSLBP) is a prevalent condition frequently encountered in clinical settings. Previous studies have demonstrated that individuals with low back pain often exhibit impaired postural control and diminished balance performance. However, the mechanisms underlying these deficits remain unclear. In particular, the association between lumbar spine mobility and postural balance has not been conclusively established. This study aims to investigate whether reduced lumbar mobility is associated with impaired postural control in patients with NSLBP. Methods A total of 91 persons diagnosed with NSLBP were enrolled in this study. Using analysis of covariance (ANCOVA) to adjust for potential confounding variables, participants were categorized based on the lumbar range of motion (ROM) and pain severity. Specifically, patients were grouped according to lumbar extension ROM (greater vs. lesser), lumbar flexion ROM (greater vs. lesser), and pain severity (mild, moderate, or severe). Postural control was assessed by analyzing center of pressure (COP) displacement in the Anteroposterior (AP) and Mediolateral (ML) directions, velocity of sway, and COP area during eyes-opened and eyes-closed standing. Results Compared to those with a greater lumbar extension ROM, patients with lesser lumbar extension ROM exhibited significantly greater COP displacement in both the AP and ML directions, as well as a larger COP area during eyes-closed standing. Additionally, patients in the severe pain group demonstrated a significantly larger COP area than those in the moderate pain group. Conclusion The findings suggest that increased postural sway amplitude in patients with NSLBP is associated with reduced lumbar extension mobility. Furthermore, pain severity appears to influence postural control performance. These results highlight the importance of evaluating and addressing lumbar mobility and pain management in the rehabilitation of patients with NSLBP. Trial registration ChiCTR2400093380(Registration date:2024-12-03).