During the last few decades, the role of sports and physical activity has become more and more important in all modern communities. Conditioning sports are generally considered positive by many governments because of their beneficial effect on human well-being. The risk of injury is increased, for both acute traumas and overuse injuries, and prevention has also become more important in sports. Epidemiologic studies are important when planning prevention programs for sports injuries. Because of individual sport cultures and different sport habits in different countries, national epidemiologic studies are of importance in each individual country.