Abstract
Purpose: The purpose of this study was to examine the direction of the force at the ankle joint that reduces the anterior shearing force at the knee joint during muscle training of the vastus using a mathematical simulation. Methods: The functional effective muscle combined with the Hill model was used to estimate the muscle forces at the knee joint. The muscle lines of action were determined using the straight line model and the wrapping surface. Behavior of the shearing force at the knee joint was simulated by systematic manipulation of the direction of the force at the ankle joint. Result: When the direction of the force at the ankle joint changed, bordering on the line connecting the hip joint and the ankle joint, the anterior shearing force at the knee joint also changed. Conclusion: The findings of this study regarding the direction of the force at the ankle joint may provide the information needed to implement a safe muscle training method for anterior cruciate ligament injuries.
