Comparison of Lumbopelvic Rhythm between Healthy Individuals and Lumbar Clinical Instability Patients

Background and Objective: The lumbopelvic rhythm is the coordinated movement of the lumbar spine and hip during trunk flexion and return. It is recognized as a clinical indicator of low back pain (LBP); nonetheless, the reported patterns of lumbopelvic rhythm in patients with LBP are inconsistent. The investigation of more homogeneous subgroups of patients with LBP is essential to clarify the lumbopelvic rhythm patterns. Therefore, the present study aimed to compare lumbopelvic rhythm between healthy individuals and patients with lumbar clinical instability. Materials and Methods: A total of 44 subjects (22 healthy cases and 22 lumbar clinical instability (LCI) patients) participated in the present study. The kinematic parameters during the trunk flexion and return task were recorded using a Qualisys motion capture system. Hip flexion angle, lumbar flexion angle, and lumbopelvic rhythm were statistically analyzed in every 25% of the flexion and return phase of flexion. Data were analyzed using Kolmogorov-Smirnov, Chi-square, and independent t-test. Results: In the second quarter of trunk flexion, the flexion angle of the lumbar spine was larger in the lumbar clinical instability group, as compared to that in the control group (P=0.016). Furthermore, the hip flexion angle was smaller in the lumbar clinical instability group, in comparison with that in the control group (P=0.011). Conclusion: These results show that the lumbopelvic rhythms are different among healthy subjects and patients with lumbar clinical instability.