Explanatory hypotheses proposed in behavioral studies assumed that less repetitive practice schedules, such as random practice, seem to demand greater cognitive effort than more repetitive types of practice organization, such as constant. All of these hypotheses emphasize the enhanced demand to memory processes promoted by less repetitive practice schedules. In the present study, we investigated the cognitive effort involved in random and constant practice schedules with an electrophysiological approach. Twenty-one male participants practiced a sequential key-pressing task with two goals: learning the relative timing dimension and learning the absolute timing dimension. Sixty trials were performed in a constant practice schedule (only one absolute timing goal), and sixty trials were performed in random order (three absolute timing goals). Two electroencephalography based measures of cognitive states were used: (a) task engagement (sensory processing and attention resources) and (b) mental workload (working memory load). The results showed that random practice induced greater cognitive effort than constant practice when task engagement was analyzed. Throughout practice, both task engagement and mental workload decreased more in the constant practice condition than in the random practice condition. The increased demand for sensory processing observed in random practice opens a new exciting field of study in practice organization.

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BACKGROUND: Manual movements are affected by the index of difficulty of the task and handedness. High index of difficulty and execution with the non-dominant hand can increase the mental workload.AIM: This study investigated the relation between the level of mental workload, the index of difficulty of the task, and handedness in manual movements.METHOD: Twenty-three right-handed male students (24.1 ± 4.3 years) participated in this study. The index of difficulty in the Grooved Pegboard task was manipulated by placing and removing the pegs and manipulation of handedness was made via right and left hand execution. Two mental workload metrics were obtained by electroencephalographic analysis: EEG-cognitive index, and EEG-workload index.RESULTS: The index of difficulty analyses indicated lower movement time when removing the pegs (low index of difficulty) compared to placing the pegs (high index of difficulty). EEG-workload index was higher when placing the pegs than removing. The handedness analyses indicated lower movement time with the right hand compared to the left hand. However, similar levels of mental workload were found.CONCLUSION: Results suggest higher mental effort when index of difficulty is increased, but not when the left non-dominant hand is performing the task.

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Pouco se sabe a respeito da associação entre o efeito da interferência contextual (EIC) e medidas cinemáticas. O objetivo do presente estudo foi investigar o EIC nos perfis cinemáticos de velocidade e aceleração do membro superior. Vinte e dois participantes (23,7 ± 3,3 anos) foram alocados em dois grupos de prática: em blocos (GPB) e aleatória (GPA). A tarefa consistiu em acertar três alvos apresentados no monitor em três sequências pré-determinadas o mais rápido e preciso possível. O estudo foi dividido em fase de aquisição e teste de transferência. As variáveis de desempenho foram tempo de reação, tempo de movimento e tempo de resposta e as variáveis cinemáticas foram pico de velocidade, tempo relativo para o pico de velocidade e número de correções para alcançar o alvo. Os principais achados mostraram que o GPA apresentou menor tempo de movimento e de resposta do que o GPB. Análise de regressão indicou que a mudança observada ao longo da prática para a medida de pico de velocidade estava associada à mudança do tempo de reação da fase de aquisição para o teste de transferência. Como o pico de velocidade é uma medida associada à pré-programação, sugere-se que o controle central seja essencial para a observação do EIC.