Alessio Bricca Lecture

Articular cartilage is explained as a sponge-like tissue that absorbs shock and helps the knee move with low friction. The lecture focuses on what happens to this tissue during exercise, especially in people with knee osteoarthritis, and addresses a common concern: whether exercise wears the joint down. Key concepts include the role of cartilage components such as chondrocytes, aggrecan, and collagen, and how cartilage depends on mechanical loading because it has no direct blood supply. The evidence reviewed moves from laboratory and animal studies to human research. In vitro and animal findings suggest a nonlinear pattern: too little loading and excessive loading may be harmful, while moderate loading appears beneficial or at least safe. Human studies are then summarized using MRI findings and molecular biomarkers. Across people with knee osteoarthritis or those at risk, exercise therapy does not appear to harm cartilage structure, composition, or inflammatory markers. The practical takeaway is that clinicians can reassure patients that appropriately prescribed, gradual exercise therapy is safe for knee cartilage, while avoiding exaggerated claims that it will definitely rebuild cartilage.