Pain-related fear is associated with avoidance of spinal motion during recovery from low back pain

Study Design. A longitudinal assessment of the association between pain-related fear and joint motions in 36 participants with subacute low back pain. Objectives. To determine how the psychologic construct of pain-related fear maps to motor behavior in standardized reaching tasks. Summary of Background Data. Pain-related fear is a significant predictor of avoidance behavior and occupational disability in individuals with low back pain. However, it is not currently known how pain-related fear maps to motor behavior. Methods. Participants with an episode of subacute LBP were tested at 3, 6, and 12 weeks following pain onset. Participants performed reaching tasks at comfortable and fast-paced movement speeds to 3 targets (high, middle, low) located in a midsagittal plane. Three-dimensional joint motions of the thoracic spine, lumbar spine, and hip were recorded using an electromagnetic tracking device. Group differences in joint excursions were assessed using 2 groups (high pain-related fear, low pain-related fear) x 3 times (3, 6, 12 weeks) x 2 movement speeds (comfortable, fast paced) x 3 target heights (high, middle, low) MANOVAs. Results. Individuals with high pain-related fear had smaller excursions of the lumbar spine for reaches to all targets at 3 and 6 weeks, but not at 12 weeks following pain onset. Conclusion. Individuals with high pain-related fear adopt alternative movement strategies and avoid motion of the lumbar spine when performing a common reaching movement. Identifying how pain-related fear maps to actual motor behavior (i.e., alternative movement strategies) is a crucial first step in determining how pain-related fear and motor behavior interact to promote or delay recovery from acute low back pain.