The analysis of knee kinematics and kinematics during high-risk movements associated with anterior cruciate ligament (ACL) injury is essential to studying the mechanism of ACL injury. Motion capture at low frame rates may not always detect the actual peak values during high-speed movements. However, the knee kinetic differences between various frame rate measurements during high-risk movements have not been reported. The purpose of this study was to investigate whether 3D knee kinetics would be measured differently between frame rates such as a high frame rate (1200 Hz), 400 Hz, 240 Hz and the popular low frame rate (120 Hz). Knee kinetics during a single-leg drop landing and side-step cutting under different frame rates were repeatedly measured and statistically compared. Peak knee valgus and tibial internal rotation moments measured at a popular low frame rate were significantly lower than those measured at the other frame rates of 400 Hz and 1200 Hz. The peak anterior and superior forces measured at the highest (1200 Hz) frame rate were significantly higher than those measured at any other frame rates. In addition, the variations in the peak kinetic values were significantly larger at the lowest frame rate capture and trended toward being smaller at the higher frame rates. In conclusion, significant differences in the knee kinetics between the frame rates suggest that the high frequency capturing increases the accuracy of the knee kinetics measurement for high risk maneuvers for the study of ACL injury.