A method and system for actively monitoring anterior cruciate ligament (ACL) strain experienced at the knee joint during athletic activity or dynamic movement. Sensors are used in proximity of the knee joint to actively record parameters such as flexion angle and ground impact force at the knee joint. Sensor measurements are then inputted into a processing unit that will quantify a tibial shear force (TSF) value based on the sensor outputs and dynamically generate user feedback and/or warning signals when unsafe levels of TSF conducive to ACL injury are detected.
