Gender Differences in Lower Extremity Kinematics and Kinetics of the Vertical Ground Reaction Force Peak in Drop-landing by Flatfooted Subjects

[Purpose] The purpose of this study was to investigate the kinematics and kinetics of the vertical ground reaction force peak during a drop-landing by flatfooted males and females. [Subjects] Twenty subjects (ten male and ten female subjects) participated. [Methods] Subjects performed a drop-landing task from 40 cm, and knee, hip, and ankle kinematics and kinetics were recorded using 12 cameras, the Vicon motion system (Vicon, Oxford, England) and 2 force platforms. [Results] A significant difference in the hip, knee, and ankle joint angles was observed in the sagittal plane between the male and female groups. Significant differences in F(x) and F(z) were observed between males and females, but no significant difference was found for F(y). [Conclusion] A higher risk of not only an anterior cruciate ligament injury but also ankle ligament injury may arise from hyper-inversion flatfooted females, compared to flatfooted males, because of lower hip joint control.