Introduction: We compared kinetic factors of the knee in healthy and injured leg and also the injured leg with healthy subjects as a control group. Method: In this study 32 college athletes (16 healthy subjects and 16 patients) participated. All in previous injured group had history of acute hamstring strain more than 3 months, without any other lower extremity injury. They did single leg jump-landing task, 3 trial for each leg and recorded by six high-speed (200 Hz) cameras (JVC) and force plate. Knee sagittal and frontal moments and knee muscles power in sagittal plane were compared between two legs of injured group and compared with healthy subjects. Paired T-test and Wilcoxon for comparing two legs of injured group, and student T-test and Manvitney were used for comparing injured and healthy groups. Results: There were no significant differences in abductor moment, extensor moment, extensor and flexor forces (p˃0.05), except the pick point of knee flexor moment between both legs (p≤0.05) and it was lower at healthy leg of injured group. Conclusion: We can conclude that negative kinetic changes are more in healthy leg.
