Several recent studies have evaluated interventional techniques designed to reduce the risk of serious knee injuries, particularly noncontact anterior cruciate ligament injuries in female athletes. Maintenance of rotational control of the limb underneath the pelvis, especially in response to cutting and jumping activities, is a common goal in many training programs. Rotational control of the limb underneath the pelvis is mediated by a complex set of factors including the strength of the trunk muscles and the relationship between the core muscles. It is important to examine the interrelationship between lower extremity function and core stability.