Allowing learners to control feedback has been an effective strategy in motor skills learning. However, most studies of self-controlled (SC) feedback have used simple tasks that may be dissimilar to sports skills that generally demand more degrees of freedom and cognition. Thus, this study investigated the effects of SC knowledge of results (KR) on learning a complex Taekwondo skill. Twenty-four undergraduate volunteers of both sexes, aged 18-35 years, practiced a specific serial Taekwondo skill that was novel to them. We divided participants randomly into SC and yoked groups and compared their performance after they learned a specific displacement sequence, finishing with a lateral kick (bandal-tchagui) at a punching bag within a target time span. During acquisition, all participants performed 48 trials divided into six blocks and, on a retention test 24 hours later, they performed 10 more trials. We found that both groups reduced their errors from the first to the last block of the acquisition phase and that the SC group showed a better performance on the retention test, relative to the yoked control group. SC KR participants requested KR mainly after good trials, though they showed no statistically significant differences between trials with and without KR. Their inefficiency in estimating their own errors may have been due to task complexity, since many aspects of the task beyond its temporal requirement demanded the learners’ attention. Our results, using a novel Taekwondo serial skill, confirm and extend the benefits of SC KR from just simple motor learning in past studies to learning complex motor skills.

Gradual increment on practice variability IntroductionGradual increment on practice variability: effects on structure learning and skill parametrization CDD. 20.ed. 152 . A feature of this practice is that it should not be a mere repetition of a speci c solution to a problem, but the repetition of the process of solving motor problems 5-6 which leads the learner to the selection of the most appropriate responses to each motor problem.In this process, the way the practice is scheduled in uences the acquisition of motor skills [7][8][9][10][11][12] . Practice has been scheduled in constant, blocked, serial and random fashion 3, 10-11 . A varied practice schedule has been regarded as more effective as constant practice [13][14][15] , as random and serial practice have been acknowledged as more e ective than blocked practice in the learning of motor skills 10,[16][17][18] . Conversely, contrasting results have been found, challenging the superiority of the varied practice over constant practice and the advantage of random and serial practice over blocked practice [19][20][21][22][23][24] . As a result of such controversy, the combination of constant and varied practice was employed [7][8]20 with favorable results on the acquisition of motor skills, particularly in the initial stages of Abstract Traditionally, on the learning of motor skill practice has been scheduled in constant, blocked, serial or random fashion. A superiority of variable over constant practice has been suggested as well as random and serial practices over blocked practice. Recently a specifi city of the type of practice has been observed: constant practice helps the formation of a movement structure, especially in the early learning, and the variable practice improves parameterization. This study investigated different practice schedules and their combinations in a sequence that provides a gradual increment of variability (constant, blocked, and random) in the acquisition of motor skills. Participants were divided into four groups (n = 10): CCC (constant), BBB (blocked), RRR (random) and CBR (constant-blocked-random). The experiment consisted of an acquisition phase and a transfer test. In the acquisition phase the task comprised pressing a numeric keyboard in a given sequence (2,8,6,4) with the index fi nger, with fi xed relative timing among presses (22.2%, 44.4% and 33.3%) and specifi c total times (700, 900 and 1100 ms) determined by the experimental design. The test results showed a superiority of CBR and RRR groups in the absolute error measure, of CCC and BBB groups in the relative error measure, and CCC, BBB and CBR groups in the variability of relative error measure. These results evidence the practice schedules that provided smaller variability led to the learning of a movement structure, whereas the ones that provided greater variability culminated in the improvement in parameterization.

This study aimed to investigate the combined practice schedule on learning both the movement pattern and precision of a complex sports motor skill. Based on pretest performance, sixteen participants (14.19 ± 1.80 years-old) were counterbalanced into two groups, random practice and combined practice. During the acquisition phase, the participants performed 252 trials of the Japanese volleyball serve divided equally into six sessions. The score of movement pattern and score of serve precision measures were analyzed on the pretest and retention test. The results showed that combined practice led to movement pattern improvement, and random practice improved serve precision. These results give support to the proposition that movement patterns and parameters have distinct structures of control. Also, the results indicate that combined practice needs a higher amount of random practice to promote parameters improvement.