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Cartilage Metabolism in Endurance Athletes and Chondroprotective Action of Glucosamine

In endurance athletes with intense joint loading, cartilage metabolism (degradation of type II collagen) is enhanced compared with non-athletes and non-endurance athletes. Recently, we have revealed that glucosamine, a functional food, exerts a protective action on cartilage metabolism in not only osteoarthritis patients but also endurance athletes (such as soccer players) by suppressing the degradation of type II collagen. In this review, to demonstrate these findings, the following topics will be presented: 1. Biomarkers for cartilage metabolism; 2. Evaluation of cartilage metabolism in endurance athletes by using biomarkers for cartilage metabolism; 3. Chondroprotective action of glucosamine on endurance athletes.