I Brage finner du siste tekst-versjon av artikkelen, og den kan inneholde ubetydelige forskjeller fra forlagets pdf-versjon. Forlagets pdf-versjon finner du på bjsm.bmj.com: http://dx.doi.org/10.1136/bjsm.2009.071159 / In Brage you'll find the final text version of the article, and it may contain insignificant differences from the journal's pdf version. The original publication is available at bjsm.bmj.com: http://dx.doi.org/10.1136/bjsm.2009.071159 ; Background: Limited knowledge exists on injuries among professional freestyle skiers. Objective: To describe the risk of injury and injury patterns among competitive World Cup (WC) freestyle skiers during the competitive season. Methods: Retrospective interviews were conducted with WC freestyle skiers from 20 nations in a cohort study at the end of the 2006–2007, 2007–2008 and 2008–2009 winter seasons, and all acute injuries occurring during the 4.5 month competitive season were recorded. If an athlete was not present, we interviewed his or her coach or medical personnel. Results: A total of 291 acute injuries were recorded among 662 WC freestyle skiers. Ninety-three injuries (32%) were severe in nature, defined as >28 days absence from training/competition. This corresponds to 14 (95% CI 11.2 to 16.9) injuries per 100 athletes per season. The most frequently injured body part was the knee with 77 injuries (27%) and 37 of these were severe. The head was the next most commonly injured body part with 39 (13%) injuries. As many as 106 injuries (36%) occurred during WC/World Ski Championship competitions, corresponding to an injury rate of 15.6 injuries per 1000 runs (95% CI 12.7 to 18.6). There were no significant differences between men and women in either the injury rate or the rate seen for knee injuries. Conclusions: The injury rate among WC athletes in freestyle skiing is high, especially for severe injuries. The knee is the most commonly injured body part, also dominated by severe injuries. We found no significant difference in the injury rate related to sex.