A recent literature review (Fong 2007) show that the ankle was the most common injured body site in 24 of 70 included sports, especially in aeroball, wall climbing, indoor volleyball, mountaineering, netball and field events in track and field. Ankle sprain was the major ankle injury in 33 of 43 sports, especially in Australian football, field hockey, handball, orienteering, scooter and squash. Despite the fact that this is a common injury, the mechanism is still unclear. A new study (Fong et al. 2009) indicates that the mechanism of injury may be substantially different from what has been believed previously. In opther words, it may be necessary to describe ankle joint motion in several such situations. The aim of this study is therefore to collect and analyse 10 lateral ankle sprain videos. The videos will be analysed using a model-based image-matching technique (Krosshaug & Bahr, 2005).