Factors causing predisposition to knee exertion injuries were sought by means of a questionnaire and detailed anthropometric measurements in 39 Finnish Army conscripts picked from a random sample of 56 army conscripts. The subjects consisted of two groups of 18- to 23-year-old conscripts; Group A comprised 29 subjects without knee exertion injuries and Group B 10 subjects who had experienced knee exertion injuries during the physical training program of the first eight weeks of military service. In Group A the physical activity level preceding the military service was somewhat higher than in Group B. In Group B the skeletal dimensions were longer and the body fat percentage was higher than in Group A. We conclude that big size of the subjects predisposed to knee exertion injuries during the training program.