Athletes are particularly at risk for anterior cruciate ligament injury, and there is some evidence that female athletes are more at risk than males. The conflicting principles of stability and mobility are at odds within the knee, setting the stage for potentially serious injuries. Some investigators suggest that the size of the intercondylar notch should be used to identify athletes at risk for ACL damage, but more research is required before clinical decisions can be based on notch width measurements. Athletic shoe modifications and artificial playing surfaces may influence the incidence of ACL injures. Functional knee braces appear to have beneficial strain shielding effect on the ACL for anterior directed loads and internal–external torques applied to the tibia, but this effect appears to decrease as the magnitude of these anterior directed loads and torques increases. Ski equipment is often pointed to as a contributing factor in ACL injuries, but there is no evidence that modifications in ski equipment will decrease ACL disruptions. An education program based on recognizing the events that lead to ACL injury in skiing may reduce knee injuries in the future.