Lower extremity stiffness and dynamic valgus knee motion deficit are independently recognized and considered as a risk factor for anterior cruciate ligament injury. Also, several studies have pointed out a strong relationship between hip muscle dysfunction and dynamic knee valgus movement defects. However, there is no evidence to investigate the correlation between the ratio of isometric strength of abductor to adductor muscles as well as external rotator to internal rotator of the hip and stiffness of the lower limb, knee valgus dynamic defect during movement tasks. In fact, the correlation between these variables is still unknown. Therefore, it seems necessary to conduct a study aimed at investigating the relationship between lower limb stiffness and dynamic knee valgus and isometric strength ratio of hip muscles during jump-landing motor tasks. In this study, the participants will be asked to attend a session for one hour in the movement analysis laboratory of the successful candidates wearing appropriate clothing (sports shorts, etc.). In general, the ratio of the isometric strength (torque) of the hip muscles by the manual muscle test method and using a hand-held dynamometer (HHD), and the stiffness and kinematics of the lower limb joints during the DLDVJ and SLDVJ jumping landing movement tasks using motion analysis systems and The force plane will be measured and calculated. It should be noted that the participants will perform each movement task 3 times with a 30-second rest between repetitions and a two-minute rest between movement tasks.