Born to run: The paradox of biomechanical force in spondyloarthritis from an evolutionary perspective.

Spondyloarthritis (SpA) refers to a group of chronic inflammatory arthritic diseases that can be severely debilitating. The most common form of SpA affecting the peripheral skeleton is psoriatic arthritis, while that affecting the axial skeleton is ankylosing spondylitis. SpA has a multifactorial nature, with both genetic and environmental factors initiating and maintaining the disease. Recently, the role of biomechanical stress as an initiator of disease has gained much attention, with efforts focusing on the underlying cellular and molecular mechanisms. In this review, we provide a different view, with emphasis on the apparently contradictory role of physical therapy in SpA owing to the impact of biomechanical stress and put this in an evolutionary context due to changes in environment and lifestyle across time.