Continuous lumbar spine rhythms during level walking, stair climbing and trunk flexion in people with and without lumbar disc herniation

Low back pain(LBP) is one of the most prevalent diseases afflicting people today. Abnormal musculoskeletal loadings during activities of daily living (ADLs) have been deemed to be associated with spine rhythm. But no studies have reported abnormal continuous spine rhythms during ADLs in LBP patients. Therefore, the objective of this study was to investigate the continuous lumbar spine rhythms and their difference between people with and without lumbar disc herniation (LDH). Twenty-six healthy people and seven patients with LDH were recruited in this study. They performed level walking, stair climbing, and trunk flexion. Active optical markers placed on the landmark of the spinous process and pelvis were captured using motion analysis system to drive a musculoskeletal model to calculate the continuous lumbar spine rhythms. It was found that the lumbar spine rhythm was roughly constant throughout the analyzed cycle in both healthy people and LDH patients during trunk flexion. LDH patients displayed fluctuant lumbar spine rhythms during level walking and stair climbing and significantly higher segmental contributions of the lumbar segments in the lower lumbar region during stair climbing and trunk flexion. In conclusion, there were different compensatory responses to LDH in the continuous lumbar spine rhythms during different ADLs. This study provides a new insight into the abnormal spinal motion in LDH patients.