title: The relationship between ACL injuries and physical fitness in young competitive ski racers: a 10-year longitudinal study.
abstract: BACKGROUND
  Epidemiological studies have shown a high incidence of anterior cruciate ligament (ACL) injuries among competitive alpine skiers. Little is known regarding modifiable risk factors in young skiers. There are still uncertainties in gender-related risk factors.
  
  
  OBJECTIVE
  The purpose of this study was to determine the relationship between ACL injuries and internal risk factors.
  
  
  METHODS
  Retrospective data analyses were performed based on a group of 175 female and 195 male alpine ski racers between the ages of 14 and 19 years. The athletes underwent physical testing annually from 1996 to 2006. Z score transformations normalised the age groups. Multivariate binary logistic regressions were calculated for men and women separately to detect significant predictors of ACL ruptures. t Tests were computed to reveal the differences in test scores between injured and non-injured athletes.
  
  
  RESULTS
  A total of 57 (15%) ACL injuries occurred. The female-male risk ratio (RR) was higher in females (2.3, 95% CI 1.3 to 4.2). Z scores for relative leg force, ratio of absolute core flexion to extension force, relative core strength and reactive strength index were predictive variables for men. Z scores of all of these predictive variables except relative leg force were higher in the non-injured group. The ratios of absolute flexion to extension force and absolute core strength were predictive covariates for women. Z scores for absolute core strength were higher in the non-injured group.
  
  
  CONCLUSIONS
  The risk of ACL injury was greater in female athletes. The findings suggest that core strength is a predominant critical factor for ACL injuries in young ski racers.
authors.affiliation: Department of Sport Science, University of Innsbruck, Innsbruck A-6020, Austria. Christian.Raschner@uibk.ac.at
authors.forename: Christian
authors.initials: C
authors.lastname: Raschner
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Platzer
authors.forename: Carson
authors.initials: C
authors.lastname: Patterson
authors.forename: Inge
authors.initials: I
authors.lastname: Werner
authors.forename: Reinhard
authors.initials: R
authors.lastname: Huber
authors.forename: Carolin
authors.initials: C
authors.lastname: Hildebrandt
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D000070598:Anterior Cruciate Ligament Injuries; D000886:Anthropometry; D016022:Case-Control Studies; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010809:Physical Fitness / Q000502:physiology*; D012307:Risk Factors; D012421:Rupture / Q000209:etiology; D012737:Sex Factors; D012865:Skiing / Q000293:injuries*; D055815:Young Adult