Deterministic accessory spinal movement in functional tasks characterizes individuals with low back pain

OBJECTIVES: To apply a novel method to assess the characteristics of spinal movement in subjects with low back pain (LBP) in a functional task.

METHODS: 17 subjects suffering from chronic non-specific LBP (average pain intensity: 1.8±1.6), and 17 age and gender matched controls performed a repetitive lifting task. Spinal movement was recorded using a novel sensor strip with 12 angle sensors recording the spinal dynamics in evenly spaced (25mm) locations along the spine. Recurrence quantification analysis was applied to different components of the angles to assess the structure of its variability.

RESULTS: Mechanically, the LBP and control group performed the task similarly. Reported pain increased in the LBP group, yet task-related angular movement was not different. However, the percentage of determinism for the accessory angular movement (movement variability not directly related to task execution) was significantly higher for the LBP group, indicating a more deterministic (less random) structure of the muscle activation pattern variability.

CONCLUSION: The structure of the variability of spinal movement differs in subjects with chronic non-specific LBP.

SIGNIFICANCE: The determinism of accessory spinal movement may be a useful measure for evaluation of movement impairment in LBP and for monitoring rehabilitation effects.