Gymnast and injury information on 178 competitive female gymnasts was collected through questionnaires and interviews in a 3-year prospective epidemiologic study. The injury rate was 30/100 gymnasts/year, .52 injuries/1000 h. Injury rates excluding risk exposure increased with competitive level, but the top level gymnasts had the lowest rate per 1000 h of practice. Fractures of the wrist, fingers and toes were most common, followed by sprains of ankle and knee. Nearly 40% of the sudden-onset injuries occurred in the floor event. 'Missed move' was most frequently cited as the injury mechanism, while somersaults and handsprings were the most injury-producing moves. Most injuries happened with moves that were basic or moderately difficult and well-established. There was an increased chance of injury when the gymnast had been on the apparatus for an extended period of time. One major source of injury is loss of concentration, and a key to injury prevention may be the reorganization of the practice session.