The possibility of reducing the incidence of injuries in long-distance runners was investigated in 41 recreational long-distance runners. They were divided into two matched groups according to age, sex, weight, height, experience, training and incidence of injury during the previous year. The runners in the study group were clinically investigated before the season started, and individual training programmes were drawn up. The other group served as controls. The runners receiving prevention and training programmes improved in training technique and had increased training mileage, race participation and racing mileage. In 1 year a total of 50 injuries were recorded, 29 in the study group and 21 in the controls. The injury incidence per 1000 hours of competition was significantly lower in the study group with a preventive training regimen than in the controls (30.7 versus 62.5).