Background Epidemiological studies have shown a high incidence of anterior cruciate ligament (ACL) injuries among competitive alpine skiers. Little is known about modifiable risk factors and there is still equivocal discussion about the gender-related risk factors.

Objective To determine the relationship between ACL injuries and internal risk factors among competitive junior alpine skiers.

Design Retrospective data analyses of a cohort.

Participants 175 female and 195 male competitive alpine ski racers between the ages of 14 and 19.

Assessment of risk factors Athletes of the Skigymnasium Stams underwent a test battery three times annually from 1996 to 2006. Norm profiles were established and Z score transformations normalised the different age groups. In the case of an ACL injury the last test result before the injury was compared with the norm values.

Main outcome measurements Physical parameters between injured and non-injured athletes.

Results Between 1996 and 2006, 57 ACL injuries occurred. The injury rate in females was 2.1 times greater than in males. The binary logistic regression revealed Nagelkerkes R² of 0.368 and 0.236 for men and women, respectively. Z scores for relative leg force, ratio of absolute flexion/extension force, relative core strength and reactive strength index were predictive variables for men. Z scores of all these predictive variables except relative leg force were higher (p<0.05) in the non-injured group than in the injured group. Ratio of absolute flexion/extension force and absolute core strength were predictive covariates for women. Z scores for absolute core strength were higher in the non-injured group (p<0.01).

Conclusion The risk of injury was higher in females compared with males. Findings suggest that core and leg strength are critical factors for ACL injuries in young ski racers. Targeted evidence-based preventative training programs must include these aspects.