Two optoelectronic systems: a SMART DX 400 system (BTS SPA, IT) with 8 video cameras  (100 Hz) and a SMART system (BTS SPA, IT), with 6 cameras (50 Hz). Both measure the three-dimensional coordinates of markers. From these cordinates it is possible to calculate trajectories, angular sizes (e.g. angles of flexion-extension, abdo-adduction and extra-intra rotation of the main articulations), speed, accelerations and to know in detail the kinematic of the movement of the physical segment where the markers have been positioned.