The relationship between ACL injuries and physical fitness in young competitive ski racers: a 10-year longitudinal study

• Published in: British journal of sports medicine Vol. 46; no. 15; pp. 1065 - 1071
• Main Authors: Raschner, Christian, Platzer, Hans-Peter, Patterson, Carson, Werner, Inge, Huber, Reinhard, Hildebrandt, Carolin
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine 01.12.2012; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: ACL; Adolescent; Adolescents; Age Distribution; Anterior Cruciate Ligament Injuries; Anthropometry; Athletes; Case-Control Studies; Epidemiology; Exercise; Exercise Test - methods; Female; Fitness testing; Health risk assessment; Humans; Knee; Ligaments; Longitudinal Studies; Male; Physical fitness; Physical Fitness - physiology; Risk Factors; Rupture - etiology; Sex Factors; Ski injuries; Skiing; Skiing - injuries; Sports injuries; Studies; Young Adult
• ISSN: 0306-3674; 1473-0480
• DOI: 10.1136/bjsports-2012-091050

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.