The first 4 BALT's were carried out by placing the pressure platform on the floor, a stable surface. These tests were: 1) Open Eyes (EO) with a fixed point to evaluate all the systems involved in the postural control (visual, vestibular, somatosensory); 2) Eyes Closed (EC) to evaluate the vestibular and somatosensory system, while eliminating the visual sensory input; 3) Eyes Open while actively moving the head up and down (HUD) to evaluate the visual and somatosensory system, while altering the vestibular system with head movements (EO HUD) (For HUD movements a metronome 2/4 60 BPM was used to maintain a fixed frequency of about one spin per second in motion); 4) Eyes closed and actively moving the head up and down (EC HUD) to assess the effect of removing the visual input, in combination of an alteration of the vestibular system with the head up and down movements.