Background Alpine skiing is one of the most popular winter sports worldwide. Like other sports alpine skiing can lead to severe injuries irrespective of skiing level. Several epidemiological studies in alpine skiers have reported the knee to be the most frequently injured body part and anterior cruciate ligament (ACL) injury the most common diagnosis. An ACL injury is serious and regardless of gender it constitutes a risk for the skier´s career as well as for early osteoarthritis. Therefore, it is of utmost importance to prevent ACL injuries.

Methods This clinical trial is the fourth step in van Mechelns “Sequence of prevention” which is the optimal way to develop an injury prevention program. The intervention group consisted of all available skiers studying at a Swedish ski high school during the ski seasons 2011/2012 and 2012/2013 (n = 308). Skiers, who attending the ski high schools during the seasons 2006/2007 to 2010/2011 assembled to be a control group (n = 456). The prevention program included a video included education on awareness of how to avoid getting into ACL injury situations and exercises focusing on neuromuscular control and core stability. The goal of the prevention was to be equally good on both legs when performing different exercises indoors as well as outdoors on snow. The outcome measure consisted of the number and incidence of ACL injuries during the two year study period in comparison to the five control years.

Results In the control group 35 ACL injuries occurred showed a prevalence of 8%. During the intervention years 12 ACL injuries occurred gave a prevalence of 3.9%.

The absolute risk rate showed a decreased incidence rate of −0.22 (CI: −0.44–0.00)/100 months attending a ski high school in favour of the intervention group.

Conclusions A prevention program focused on skiers ability to perform equilaterally can lead to prevent ACL injuries in adolescents competitive alpine skiers.