Grasping influence on reaching in static and dynamic condition in healthy adults

Kinematic of the hand was examined both in static and dynamic conditions to exploit the effects induced by the final grasp on the entire prehension movement. The main findings were that the subjects modify their movement accuracy and the time of object contact and finger extension in relation to the selected grip. Before the movement onset, subjects tend to display a different fingers configuration in response to the end-grip requests. Indeed, according to increased accuracy demands, they show different points of hand-object contact along the trajectory of the target. The results are consistent with the hypothesis that reach-to-grasp is both pre-planned and in continuous evolution during the entire prehension movement. This organization allows motor control to adopt different strategies according to task, context variation and individual solution based on previous experiences.