Anterior Cruciate Ligament (ACL) injuries occur often in competitive sports such as soccer, basketball, football, and more. Athletes of all ages are at risk of experiencing this injury due to living highly active lifestyles. ACL injuries account for over $500 million in total medial cost in the United States, with about 150,000 annual occurrences of injury. Much research over this knee injury has been conducted as early as 1850, but confirmation of definite mechanisms of ACL injury have proved to be a difficult endeavor due to conflicting results found from experiments. Solving this problem could lead to implementation of preventative measures to help reduce to number of victims that undergo ACL injuries. The intention of this paper is to review the state-of-The-Art of ACL injury research, including possible mechanisms of injury and the experimental methods used to analyze ACL performance.