The bandwidth knowledge of results regarding the task of the overhand serve in volleyball

Abstract Aim: Motor learning is considered a complex process, providing numerous investigations. Knowledge of Results (KR), a kind of extrinsic feedback, is one of the variables that are used for investigations on motor learning. There are different ways to provide KR to optimize motor learning. The bandwidth KR is one of these forms, being a factor that affects motor learning, however, the specificity of the task needs to be considered in the investigation of this theme. Thus, the objective of the study is to analyze the bandwidth of KR in the acquisition of motor skills of the overhand serve in volleyball. Methods: The sample consisted of 24 volunteers of both sexes (12 men and 12 women), 18 to 35 years of age (M = 27, SD = 3.46) and inexperienced in the task. The effect of the bandwidth was analyzed in two groups (with range and without range), in which the volunteers had to learn to control their force by performing the volleyball tennis type service in order to hit a target line. Performance was inferred by the mean and standard deviation of absolute, constant and variable errors. Results: There was no statistically significant difference between the groups and the volunteers improved both the precision (absolute error and constant error) and in the consistency (variable error) during the acquisition. There was an improvement in the groups also in the transfer test in the precision measures. Conclusion: The variable bandwidth is similar to a control condition in which the volunteers have information at each attempt, causing dependence on external information.

Constant-blocked practice: variation of parameters improves motor skill acquisition

AIMS: The purpose of this study was to investigate the effects of the combination of constant and variable practice when both, motor program and parameters on absolute and relative dimensions of a task, are manipulated. METHOD: Twenty undergraduate students, aged between 19 and 24 years, participated in this study. Two groups practiced the task of pressing four keys of a numeric keyboard with total and relative times specified under constant conditions in the first part of the acquisition phase and under block conditions in the second part when one group varied parameters and another varied motor programs. RESULTS: Both groups improved parameters and motor program measures during the acquisition phase. In the retention test, the parameters variation resulted in higher accuracy on motor program measure that the variation of motor programs. CONCLUSION: Both combinations improve parameters and motor program accuracy. Moreover, the maintenance of GMP during the variation phase contributes to strengthening it.(AU)