Information about a piece of news titled New PhD: How do ACL injuries happen in World Cup alpine skiing?
New PhD: How do ACL injuries happen in World Cup alpine skiing?
Intoduction
On Friday April 5, physiotherapist Tone Bere defended her PhD-thesis, entitled “Mechanisms of injuries in World Cup alpine skiing”.
With this year´s World Championship and Lindsey Vonn´s tragic knee accident in mind, the topic of Tone Bere´s PhD-work to analyze knee injuries in World Cup Alpine skiing is hot.
The day after Lindsey Vonn, the Norwegian top athlete Kjetil Jansrud ruptured his ACL (anterior cruciate ligament) in the same Championships.
Could these injury been avoided?
For physiotherapist Tone Bere (picture), to find an answer to this question has been the drive through her 4-year project at the Oslo Sports Trauma Research Center in collaboration with the International Ski Federation (FIS).
- Alpine skiing at that level is a risky sport, and I don´t want to change the sport, take away the fun and action component,
but I would like to be able to contribute to prevent these devastating injuries from happening, says Tone Bere.
The main aim of Tone´s thesis was therefore to describe the mechanisms of injuries in WC alpine skiing, based on systematic analysis of video recordings.
Systematic video analyses of injury situations
The FIS Injury Surveillance System (ISS) has reported that during the five-month winter season, one in every three World Cup (WC) alpine skiers sustains an injury. Similar to recreational skiers, the most common injury in ski racers is a knee injury, and the most frequent specific diagnosis is a complete rupture of the ACL.
Slip-Catch injury mechanism
7 international experts in the field of skiing biomechanics and sports medicine related to alpine skiing performed visual analysis of each ACL injury case to describe the inciting event in detail i.e. the skiing situation, skier behaviour and biomechanical characteristics at the time of injury.
The Slip-Catch mechanism was identified as the most common injury mechanism for an ACL injury and characterized by a common pattern were the skier lost pressure on the outer ski while turning, and while extending the outer knee to regain grip, the inside edge of the outer ski caught abruptly in the snow, forcing the knee into internal rotation and valgus
Slip-catch (right knee). A: the skier is out of balance backward and inward in the steering phase out of the fall line. B: as the skier tries to regain snow contact with the unweighted outer ski, he extends his right knee. C (injury incident): the outer ski catches the inside edge abruptly, forcing the right knee into valgus and internal rotation. D: the skier falls backward to his right.
The other 2 identified injury mechanisms are called «the landing back-weighted» and «the dynamic snowplow».
Skier errors as one of the main injury reasons
– I often follow discussions on why we do see all these serious injuries. Is it a skier error? Was the course too difficult, the snow conditions and visibility too bad? Are the individual technical skills good enough for the World Cup level?
In one of her papers, Tone tried to find an answer to these discussions.
– Skier errors, mainly technical mistakes and inappropriate tactical choices, were the dominant factors, Tone adds.
The illustration above is from the 4th paper showing a biomechanical animation of an injury situation allowing researchers to extract detailed information on the positioning and movements of body segments during the injury motion.
Professor Roald Bahr and Professor Lars Nordsletten have been Tone´s supervisors.
Read more about Tone´s PhD-project and publications.
Dissertation Committee
Chair: Professor Kari Bø, Norwegian School of Sport Sciences, Norway
1. Opponent: Professor Jón Karlsson, Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg Sahlgrenska University Hospital/Mölndal, Sweden.
2. Opponent: Dr Arne Kristian Aune, Terres Drammen, Drammen, Norway.
Program on April 5 (Aud A, Norwegian School of Sport Sciences)
10:15 - 11:00 Trial lecture "Is there scientific evidence to recommend core training in the prevention and treatment of lower back pain”
13:15 - 16:00 PhD presentation and defense
Welcome to this open ceremony!
The trial lecture and the PhD defense will be held in Norwegian.