ORGANIZATION OF LOCAL ANTICIPATORY MOVEMENTS IN SINGLE-STEP INITIATION

The study deals with the segmental organization of single- and multi-s tep walking. Local (segmental) and global (center of gravity) anticipa tory movements associated with the initiation of the stepping movement were investigated in 5 normal subjects. Each subject performed a sing le-step walking task under three conditions of step velocity. Global a nticipatory phenomena were indicated by the acceleration of the center of gravity and displacement of the center of foot pressure. Local ant icipatory movements, i.e. the accelerations of trunk, shoulders, hips and shanks were recorded simultaneously. The biomechanical data sugges t that there are two distinct parts in the anticipatory phase. The ear lier correspond to the static postural changes, which are correlated t o the velocity of the forthcoming movements. As in multi-step walking, global and local accelerations are specific to the forthcoming moveme nt. The latter part aims to counterbalance the disruption induced by h eel-off and is related to postural necessities. These results suggest that the same parameters are programmed in the execution of the single - or multi-step walking process.