Kartläggning av ACL-skador inom alpin skidåkning

Abstract

ACL injuries, anterior cruciate ligament injury, are a major problem in the Alpine Skiing World Cup. Earlier research focuses on how injuries can be prevented through preventive physical exercise and how skiers should rehabilitate after an injury. Hence, this study intends to approach this problem from a more technical point of view by studying forces and stresses. If the forces that expose the skier can be identified, a study can be made in order to investigate what causes the ACL injury. A literature search and a video analysis were used to identify injury mechanisms. The literature search explains the function and structure of the knee joint, ligaments and ski equipment. There are a lot of different factors that affects an injury such as the discipline, snow conditions and regulations as well as physical and mental differences between genders and skiers in general. It is easy to identify the forces that expose the skier when the skier is in balance, however in an injury case the forces are difficult to identify and analyse. This report argues that the risk of ACL injuries increases when the skier is out of balance. This often precedes an injury mechanism. A valgus force to the knee is also identified as an injury mechanism, which in worst case leads to an ACL tear. The valgus force creates a torque on the ligament, which is the reason why it tears. The video analysis studies three injury cases which all shows that a combination of several factors lead to the injury mechanism and causes the ACL injury. The analysis covers three different injury mechanisms: slip-catch, sitting back weighted and valgus. All mechanisms lead to ACL injuries. By analysing the forces that expose the skier, concepts regarding the equipment can be developed in order to prevent ACL injuries.