1. Introduction to epidemiology
2. Soccer injury epidemiology
3. Reliability of soccer injury epidemiology studies
4. Ekstrand and Gillquist propose stretching and strengthening
5. Keller et al advocate warm up and stretching
6. Hawkins and Fuller identify fatigue as a factor
There have been numerous epidemiological studies related to soccer, undertaken in numerous countries and employing various methods of data collection. The diversity of the research poses a problem to the reader, as it makes it difficult to interpret the findings in a comparable manner. Kraus and Burg (1970) state that the inconsistent collection and recording of data is a fundamental problem with sports epidemiological data, which decreases uniformity and subsequent reliability. They argue that the dominant element to this end is the research objective which must be clearly stated. Furthermore, the data collection source must be reliable, otherwise the data will be of poor quality and of insufficient depth. Kraus and Burg (1970) state that probably the biggest problem in sports epidemiology is the definition of an injury, since "a sports injury is a relative event...where is the cut off point between pre-clinical unapparent injury and gross or severe anatomic trauma?"