This program of investigation was conducted to determine the nature and magnitude of the physical parameters which most significantly affect the degree of trauma produced by impact to the knee. Drop weight testing of unembalmed cadaver limbs utilizing a load cell to record forces and high-speed motion pictures to follow the kinematics of impact were the experimental techniques used.The principal results were: 1. Movement of the leg and deflection of the flow are very significant in reducing the energy absorbed by the knee and hence the trauma produced. 2. The severity of trauma produced depends on both the impact energy absorbed and the peak forces generated. As the impact energy absorbed increases, the tolerance peak forces drop.Finally, consideration is given to the application of these results to improving transportation safety and to methods for evaluating such improvements.