The popularity of different sports activities has increased during the last three decades, a development that has been considered beneficial in many respects for society as well as the individual. One of the deleterious effects of this development, however, is an increased number of sports injuries. The exact incidence of sports injuries is difficult to calculate due to many potential biasing circumstances like data collection, definition of sports injuries and the lack of suitable control subjects. In a large study where the acute accidents in Finland were examined the incidence of sports injuries was 670/10,000 inhabitants in 1987. Seven per cent of the total number of injuries seen at a large casualty department were sports injuries. The main purpose of studying sports injuries is to identify the sportsmen at high risk of injury and the main risk factors. Only in this way can preventive measures be undertaken in an effort to make participation in sports safe, regardless of the level or type of sports practiced.