The present invention relates to a system (10) operable to evaluate spasticity in a movable extremity (12). The system (10) comprises a fixation device (14) comprising a first part (14.sub.1) connected via a movable joint (16) to a second part (14.sub.2). The fixation device (14) is operable to fix the movable extremity (12) in such a way that the rotational axis of the fixation device (14) is aligned with the rotational axis of the joint of the movable extremity (12). The system (10) also comprises a moving device (18) operable to move the second part (14.sub.2) with a first, constant velocity (V.sub.1), without any reflex contribution, and with a second , constant velocity (V.sub.2) with reflex contribution. The system (10) also comprises a force sensor (20) operable to measure a first force trace in connection with the first velocity (V.sub.1), and a second force trace in connection with the second velocity (V.sub.2). The system (10) also comprises a to the force sensor (20) connected processor means (22) operable to extract a first (P1) and second maximum point (P2) from the second force trace, and a third point (P3) from the first force trace, which three points (P1-P3) are used to evaluate spasticity.