That does describe the typical contact trauma leading to ACL injuries from football, soccer, or rugby injuries. If the force from the outside across to the inside of the knee is enough, the ligament(s) inside the joint can rupture.
However, most of the time the mechanism of injury is from a noncontact injury. The quadriceps muscle is eccentrically contracted (going from a shortened to a lengthened position). The knee is in about 20 degrees of flexion (slightly bent). Then internal rotation of the tibia occurs and the ligament ruptures.
Picture this as the athlete is coming down from a jump. The foot is in contact with the floor, the knee is bent and then twists. Since the foot is planted and can't move, if the force is great enough, the knee has to give. Not all noncontact injuries occur in just this fashion, but you get the general idea of how it happens without being tackled or kicked.