A considerable amount of money has been spent on sports injuries around the world, mostly on the anterior cruciate ligament. Injury usually occurs when one changes speed or direction drastically during landing movement. The study on sports biomechanics provides insights into mechanism and risks of the injury, and thus enables scholars to devise methods of taking various precautions. A lot of previous researchers have developed many divergent theoretical perspectives. However, this present article is about to introduce side-to-side asymmetries of "leg dominance theory", which applies to the theory of two-legged landing movement. Hopefully, this study can provide for further investigations.