Abstract: A crash test dummy lower leg structure having a lower leg unit consisting of a tibia member provided with upper and lower tibia sensors. An ankle-foot assembly connected to the lower tibia sensor has a ball and socket connection between the ankle shell and foot member. Means are provided to restrict movement of the ball, to which the foot member is connected, to rotation about three mutually perpendicular axes which intersect at the center of the ball. A knee clevis sensor is connected to the upper tibia sensor and has a pair of spaced parallel members designed to sense and measure force along a line between the knee pivot and the ankle pivot.