Abstract: A joint motion measurement apparatus includes securing mechanisms that secure sensors to various body parts such as the leg, including the femur, tibia, malleoli and/or calcaneus. The sensors are configured to measure a position and/or motion of the various parts of the leg relative to one another. The sensor data is usable to determine kinematic and/or muscle properties of the leg including knee laxity, tibiofemoral measurements and/or spastic properties.