The ACL runs diagonally in the middle of the knee. Its main function is to provide rotational stability to the knee and resisting anteriorly directed shear and internal rotation forces going through the tibia in relation to femur
How does the injury occur in skiing?
According to Hame, et al. (2002), most knee-related skiing injuries are linked to traumas to the ACL (which constitute 25-30% of all injuries to the knee). There are two major mechanisms in which the ACL can be injured. Most commonly – in over 70% of the cases – an injury takes place when the skier skies in a “sitting back” position or is trying to gain back control after landing from a jump. In both scenarios, the tear occurs as a result of quadriceps muscle contraction (Hame, et al., 2002) when the athlete tries to bring the body’s centre of gravity frontward to regain balance. That enormous contraction displaces the tibia anteriorly and raptures the ACL (Ettlinger et al., 1995). Other injury mechanisms involve landing on one leg in an off-balance condition. In this scenario the initial impact force moves through the ski boot anteriorly with respect to the femur and thus raptures the ACL
Knee related injuries and their prevalence will also differ between the genders
Current studies suggest that on skis, women are at increased risk of ACL injury risk in comparison to males. This trend is directly caused by anatomical and physiological differences between the genders, such as hyperflexion or hyperextension of the knee as well as increased Q-angle which are typically more common amongst females.
Furthermore, according to
other common modifiable ACL injury risk factors include general foot dysfunction and ankle immobility, knee valgus loading, decreased muscular strength of hamstrings and quadriceps or their impaired coactivity.
Ways to help prevent ACL injuries in skiing
During our Ski Boot Fitting, we look at the biomechanical function of lower extremities, aiming to identify limitations in movement pattern and improve skiing experience by addressing these during boot fitting and customisation process. We always start with a foot assessment, followed by some static and dynamic tests to determine foot mobility of individuals.
Custom insoles for ski boots greatly improve the frontal plane alignment of the foot knee and the hip. Incorporating a muscular strengthening exercise plan is another way of significantly minimising the risk of ACL injury incidence. What we found in our Lab, is that most commonly, skiers who and suffered from an ACL injury typically show diminished core and quad strength along with hamstring and calf tightness. Occasionally, transverse pelvis rotation (to the right) may hugely contribute to ACL injury risk.