Study of anticipatory postural adjustments in an air pistol-shooting task

A segmental teleokinetic movement performed from an upright stand ing posit ion is usually preceded by a sequence of postural movements having the goal of counteracting the imbalance which will be caused by the forthcoming mov ement. This study had two aims, (1) to verify whether the postural componen t was program med in the same way as that of the teleokinetic component and (2) to verify whether the postural component was specific to the direction and speed of the movement. 12 participants performed a pistol-shooting tas k involving a rapid arm-raising movement. Three directions, two time-deadli nes, and three types of cue were manipulated. This study showed that the po stural component was sensitive to the cue effects, the characteristics of a nticipatory postural adjustments were specific to the direction of the move ment, and the characteristics of the postural muscle EMG burst were the sam e whether the participants programmed or deprogrammed and reprogrammed thei r movements for a given direction. The speed parameter did not seem to have any significant influence on the characteristics of the anticipatory postu ral adjustments.