The relationship between pain-related fear and lumbar flexion during natural recovery from low back pain.

Pain-related fear has been associated with avoidance behavior and increased risk for chronic low back pain; however, few studies have examined how pain-related fear relates specifically to motion of the spine following an acute episode of back pain. Thirty-six participants with a recent episode of low back pain were recruited from the general population using a combination of fliers and radio advertisements. To explore the natural recovery from low back pain we recruited individuals who were not seeking medical care. Participants performed a forward bending task at 3, 6, and 12 weeks following onset of low back pain. Three-dimensional joint motions of the spine and hip were recorded using an electromagnetic tracking device. Initial assessments of low back pain and pain-related fear were then correlated with joint excursions observed during each forward bending. Lumbar motion was inversely related to pain-related fear, but not low back pain, at all three testing sessions. In contrast, hip motion was inversely related to pain at all three testing sessions but was not related to fear. These findings suggest that pain-related fear results in avoidance behavior that specifically limits or restricts motion of the lumbar spine.