Why does back pain from ankylosing spondylitis often improve with activity?

Ankylosing spondylitis is a form of spondyloarthropathy characterized by chronic inflammation of the sacroiliac joints and the vertebral column.1

While the condition causes significant back pain, this pain is distinct from mechanical back pain because it typically improves with physical activity rather than rest. This improvement occurs because the inflammatory process associated with the disease—specifically enthesitis, or inflammation at the sites where ligaments and tendons attach to bone—tends to cause stiffness that is alleviated by movement. Conversely, prolonged periods of inactivity or rest often lead to increased stiffness and discomfort in the affected joints.1

Are you interested in learning more about how enthesitis contributes to other symptoms of this condition?