Abstract: A method is provided for measuring a spasticity of a muscle, comprising indenting a tapper at a particular distance into the skin, tapping a tendon associated with a muscle, and measuring the force response within a response time window. If a spastic response is detected at a particular position of the tapper according to some predefined criteria associated with the force measure, then either the position or a preload force is recorded at the first position to produce a spastic response. This determination can be used for various medical diagnoses. Furthermore, passive muscle properties can be determined by calculating a muscle stiffness value based on a line slope at at least one of the first and second indentation positions based on the maximum tapping force value at the respective indentation position.