In vitro Exercise Affects the Response of Articular Cartilage to Blunt Impact Loading

Marc A. Schlaud, under the direction of Dr. Roger Haut, Mechanical Engineering

Participation in sports, recreation and exercise (SRE) is increasingly popular and widespread in American culture, but there is an enhanced risk of musculoskeletal injury. The purpose of this study was to quantitatively assess the affect of pre-impact exercise on the response of articular cartilage to blunt force trauma. It was hypothesized that moderate exercise would cause a change in chondrocyte metabolism, altering the tissues response to injurious impact. This potential effect was hypothesized due to enhanced production of cartilage proteoglycans(PGs). Bovine chondral explants were subjected to cyclic loading while bathed in DMEM: F12 media. After 0, 7, 14, and 21 days, the explants were exposed to a 25MPa compressive impact load. Mechanical indentation tests evaluated the mechanical properties of the cartilage with a fibril-reinforced, biphasic computational model, and the PG content of the tissue was assessed. Cartilage trauma was quantified by the degree of surface fissuring and cell death. The results indicated that moderate exercise helps protect cartilage from an acute traumatic injury, such as which occurs from a fall. This chondral-inductive effect could help mitigate the potential development of a chronic joint disease, such as osteoarthritis. These in vitro results may have direct relevance athletes and the general population in a “Healthy America”.