Efeitos da prática mental na adaptação motora a perturbações previsíveis e a perturbações imprevisíveis

Abstract

Changes in environment can represent new sensory-motor demands and, sometimes, they can compromise motor performance. These changes, or perturbations, can be predictable, which allow previous action organizations; or unpredictable, which require that action organization happen only after perturbation identification. Regardless of the type of perturbation, maintaining good performance requires adaptive motor behavior that is related to previous practice, as physical and mental practice. The aim of this study was to verify the effects of mental practice in motor adaptation to predictable perturbation and to unpredictable perturbation. Two experiments were conducted with a mental practice group, a physical practice group and a control group (no practice) in each one. Participants should perform a trace as fast and as precise as possible in order to hit the target. In first phase of experiments, physical practice and mental practice groups performed the task according to practice specificity. Then, all groups were submitted to a phase of exposition to perturbations (i.e., change in target position). In first experiment perturbation were presented in a predictable way (with previous cue in the beginning of movement) and in the second in an unpredictable way (no cues). Results showed best performance of physical practice face perturbations, and the formed internal model required less number of modifications in order to achieve the goal, indicated in different measures of action organization. In general, results suggest that physical practice is superior to mental practice, which was superior to control group. These results were explained by a formation of different structures of control to each distinct kind of practice. This structure of control is internal model that relates inverse model and forward model in action organization.