Joint Cartilage

Resistance training can thicken the hyaline cartilage on the articular surfaces of the bone (Ingelmark & Elsholm 1948).

Joint cartilage depends on synovial fluid for its nutrition since it has no vascularization. Synovial fluid is forced into the cartilage surfaces when the joint is loaded, as in physical activity. Joint cartilage functions in an elastic manner during short term loading. The cartilage becomes temporarily deformed when long term loading forces water out of the cartilage. It returns to its original shape after cessation of loading when water is again drawn into the cartilage. The alternate compression and decompression along with the pumping of synovial fluid due to physical activity is partly responsible for nutrition to the cartilage.

Chondrocyte response to mechanical stimulation contributes to the maintenance of articular cartilage homeostasis. Articular chondrocyte metabolism is modulated by direct effects of shear forces that act on the cell through mechanotransduction processes. (Lane Smith 2000)

The cartilage of an immobilized joints undergo atrophy when subjected to reduced loading. Cartilage thickness is only partially restored with exercise. (Gahunia 2012)

Joint loading on cartilage results in an anabolic effects which are least partially, mediated by alterations in the synovial fluid. The composition of the synovial fluid reflects the combined extracellular pathways of all articular tissues. (Van den Hoogen 1998)

Regular exercise alters synovial fluid in such a way that it has a favorable effect on cartilage proteoglycans content, one of the main matrix components and of importance to the physical properties of cartilage. It does this by enhancing the proteoglycans synthesis and reducing the proteoglycans breakdown. Many possible candidates, including IGF-I and IGF-II, could potentially contribute in the loading effect. (Van den Hoogen 1998)

Gahunia HK, Pritzker KPH (2012) Effect of Exercise on Articular Cartilage, Orthopedic Clinics; 43(2), 187–199.

Ingelmark BE, Elsholm R (1948). A study on variations in the thickness of the articular cartilage in association with rest and periodical load. Uppsala Lakaretorenings Foxhandlingar;53: 61–64.

Lane Smith R, Trindade MC, Ikenoue T, Mohtai M, Das P, Carter DR, Goodman SB, Schurman DJ (2000). Effects of shear stress on articular chondrocyte metabolism. Biorheology;37(1-2):95-1.

Van den Hoogen BM, van de Lest CH, van Weeren PR, Lafeber FP, Lopes-Cardozo M, van Golde LM, Barneveld A (1998). Loading-induced changes in synovial fluid affect cartilage metabolism. Br J Rheumatol;37(6):671-6.