title: Potential Mechanisms Leading to Overuse Injuries of the Back in Alpine Ski Racing: A Descriptive Biomechanical Study.
abstract: BACKGROUND
  Overuse injuries of the back are a common complaint among top athletes and of competitive alpine skiers in particular. However, there is limited understanding about the sport-specific causes of these injuries that is essential for their prevention.
  
  
  OBJECTIVE
  This study was undertaken to describe the sport-specific, overall trunk kinematics and skiers' loading during giant slalom turns and to assess the plausibility of the hypothesis that a combination of frontal bending, lateral bending, and/or torsion in the loaded trunk might be a potential mechanism leading to overuse injuries of the back in alpine ski racing.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Eight European Cup-level athletes performed giant slalom runs with 2 different pairs of skis (varying in length, width, and sidecut). They were analyzed with respect to selected kinematic variables related to spinal disc loading. The overall trunk movement components (frontal bending, lateral bending, and torsion) were measured using 2 inertial measurement units fixed on the sacrum and sternum. Total ground-reaction forces were measured by pressure insoles.
  
  
  RESULTS
  During the turn phase in which the total ground-reaction forces were the greatest (up to 2.89 times the body weight), the highest average values of frontal bending (38.7°), lateral bending (14.7°), and torsion (7.7°) in the trunk occurred. Similar magnitudes were observed when skiing on longer, giant slalom skis with less width and sidecut.
  
  
  CONCLUSIONS
  The typical loading patterns of the back in alpine ski racing include a combined occurrence of frontal bending, lateral bending, and torsion in the loaded trunk. Because these factors are known to be related to high spinal disc loading, they may be considered important components of mechanisms leading to overuse injuries of the back in alpine ski racing.
  
  
  CONCLUSIONS
  Prevention measures should aim to control and/or reduce the magnitude of frontal bending, lateral bending, and torsion in the trunk, as well as the peak loads, while skiing.
authors.affiliation: Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria joerg.spoerri@sbg.ac.at.
authors.forename: Jörg
authors.initials: J
authors.lastname: Spörri
authors.affiliation: Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Kröll
authors.affiliation: Department of Orthopaedic Surgery, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Haid
authors.affiliation: Laboratory of Movement Analysis and Measurement, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Fasel
authors.affiliation: Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria.
authors.forename: Erich
authors.initials: E
authors.lastname: Müller
mesh_terms: D000328:Adult; D019567:Back Injuries / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D012090:Cumulative Trauma Disorders / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011187:Posture; D012399:Rotation; D012865:Skiing / Q000293:injuries*; D016474:Weight-Bearing
keywords: athletes; back pain; injury prevention; overuse injuries; skiing; spine