Efeitos da faixa de amplitude de conhecimento de resultados na adaptação a perturbações imprevisíveis em uma tarefa de força isométrica

Abstract

Bandwidth knowledge of results (KR) has been investigated in motor learning through retention or transfer test. However, its effects in motor adaptation to unpredictable perturbation are still unknown. The goal of this study was to investigate the effect of bandwidth KR upon adaptation to unpredictable perturbation in an isometric force task. Twenty two undergraduate students inexperienced in task participated in the study (25,14 ± 3,59 years), divided into two groups: Bandwidth Group (BG) who received KR in magnitude and direction only when the error has exceeded 5% in relation to the requested percentage of maximum force; and the Control Group (CG), which received KR in magnitude and direction whenever there was any difference between the percentage requested and executed. The study consisted of two phases: pre-exposure and exposure and the task required reach a specific goal in isometric task during three seconds. In pre-exposure phase, the goal was to reach 40% of the maximum force in 81 trials and KR was provided in accordance to the group. During the exposure phase, conducted on the next day, there were 126 more trials with the same task goal. However, it was inserted 18 trials with unpredicted perturbations characterized by a new force magnitude goal to be achieved. There were two different magnitudes of perturbations: with target goal of 60% of the maximum force (PI) and with target goal of 20% of the maximum force (PII) with nine trials each. Both groups diminished %RMSE from the beginning to the end of pre-exposure (p < 0,05) and had similar level of performance. Moreover, BG increased time within the range (p < 0,05). In intragroup magnitudes analysis, in exposure phase, it was verified that CG had higher %RMSE in PI than in PII (p < 0,05). Blocks analysis of magnitudes verified CG improvement in consistency when dealing with perturbations throughout the exposure phase (p < 0,05). BG did not show magnitude effects (p > 0,05). It was detected, however, blocks effect, demonstrating greater group consistency to handle perturbations along the exposure (p < 0,05). The intergroup analysis conducted to verify the effect of each magnitude between the CG and the BG found that the CG had higher %RMSE than BG, in the PI (p < 0,05). Also, there was a blocks effect, demonstrating consistency increase of groups to deal with PI over exposure (p < 0,05). In PII, there wasnt groups effect. It was verified, however, increasing consistency of groups to deal with the PII along the exposure (p < 0,05). The bandwidth effect occurred in PI, when BG had greater consistency than CG.