Fig. 5

Cartilage, bone, and muscle are intricately interlinked, constituting what is known as the muscle-bone unit. The muscles are key producers of the myokine irisin. Moderate-intensity exercise can promote the release of irisin by activating the PGC-1α/FNDC5/irisin signal axis in muscle, maintain the health of the cartilage and the structure of the subchondral bone, and improve muscle atrophy. Exercise can improve OA by promoting muscle–bone cross-talk of the knee joint (created with biorender.com)