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)

Assessment of motor imagery ability and training / Avaliação da capacidade e treinabilidade da imaginação motora

The aim of this study was to evaluate changes in motor imagery ability in response to a specific dart throwing training. Twelve subjects (17-22 years) with no previous experience in dart throwing or imagery agreed to participate. Changes in imagery ability were assessed using the Sports Imagery Questionnaire before (pretreatment) and after (post-treatment) an imagery training program consisting of 10 sessions. Retention (RET)was assessed 2 weeks after training. The program included mental exercises designed to develop vivid images, to control one?s own images, and to increase perception about performance. Comparison of the imagery training conditions (training alone, training accompanied, observing a colleague, and during assessment) showed no differences betweenthe pretreatment, post-treatment and RET evaluations. Although imagery ability did not respond to training, significant differences between imagery domains (visual, auditory, kinesthetic, and animic) were found (p<0.05), except between the visual and animic domains (p=0.58). These differences might be related to subject?s domain preference subject during the imagery process and to the nature of the task in which the skill technique usedseems to be a relevant aspect.

O objetivo do estudo foi determinar mudanças na capacidade de imaginação motora em resposta a um treinamento específico de imaginação do lançamento do dardo. Doze universitários (17-22 anos), sem experiência prévia no lançamento do dardo e na prática de imaginação motora participaram voluntariamente do estudo. Mudanças na capacidade de imaginação foram avaliadas usando o Questionário de Imaginação no Esporte, antes (PRE) e depois (POS) de um programa de treinamento de 10 sessões. A avaliação da retenção (RET) foi realizada após duas semanas do final do treinamento. O programa incluiu exercícios mentais destinados ao desenvolvimento da vivacidade das imagens, ao controle das imagens e ao aumento da autopercepção motora. Quando as condições de treinamento (treinando sozinho, treinando acompanhado, observando um colega e numa situação de avaliação) foram comparadas, nenhuma diferença significativa foi encontrada entre PRE, POS e RET (p>0.05). Embora não se tenha observado mudanças na capacidade de imaginação em resposta ao programa de treinamento realizado, diferenças nos domínios (visual, auditivo, cinestésico e anímico) foram encontradas. Foi observado que apenas os domínios visual e anímico não diferiram (p=0.58), enquanto os outros domíniosdemonstraram diferenças significativas (p<0.05). Essas diferenças podem refletir um domínio de preferência dos sujeitos durante o processo de imaginação e a natureza da tarefa, na qual a técnica parece ser um aspecto relevante.

Um movimento, dois olhares: a mudança de paradigma na análise do controle motor e seu efeito na abordagem da marcha humana / One movement, two perspectives: a paradigm change in the motor control

A análise de dados na ciência depende da bagagem cultural e experiência do pesquisador. Estudos sobre a marcha tem como base uma das principais teorias de controle motor: programa motor generalizado e teoria dos sistemas dinâmicos. O objetivo deste estudo foi analisar estas teorias e verificar como os estudos a partir destas correntes teóricas abordam o movimento humano denominado marcha. Foram selecionados artigos completos a partir dos unitermos: motor program, generalized motor program, dynamic system theory, gait. O programa motor generalizado analisa a semelhança dos dados para encontrar um padrão no movimento. Os sistemas dinâmicos visam analisar coordenação e variabilidade para verificar estabilidade ou emergência no movimento. Com isso os estudos a partir das duas teorias enfocam fatores diferentes para a análise e interpretação dos dados. Para a marcha a teoria do programa motor generalizado analisa a semelhança de dados de eletromiografia e cinemetria com o intuito de encontrar o padrão de movimento constante e segundo este padrão o programa motor abstrato para este movimento. A teoria dos sistemas dinâmicos visa analisar a coordenação inter e intra-membros e a variabilidade durante a tarefa para verificar a estabilidade do movimento ou a emergência de outro padrão. Pode ser caracterizado que estas duas teorias apesar de tratarem do mesmo tema, o fazem com objetivos diferentes, levando a constatação de uma divergência na abordagem e análise dos dados dependendo da teoria de base do pesquisador.

Data analysis, in any science field, depends on the investigator’s cultural luggage and experience. Among the studies regarding the motor control, two theories are currently in vogue: the generalized motor program and the dynamic systems theory. The aim of this study was to create a general view of both theories and verify how each theory explains the human movement named “gait”. To achieve this aim, full articles were selected through the following key words: motor program, generalized motor program, dynamic system theory, gait. The generalized motor program analyses data similarity in order to find a movement pattern. Dynamic systems theory verifies coordination and variability with the intention of explaining stability or emergence of a movement. Thereby, studies related to these two different theories focus on different factors when carrying out the data analysis and interpretation. Regarding the human gait, the generalized motor program theory analyses the similarities between the electromyographic and kinematic data in order to find a constant movement pattern and the abstract motor program of this movement. The dynamic systems theory aims to analyze intra-limb and inter-limb coordination and the variability during the task execution in order to verify the movement stability or the emergence of another pattern. By this means, despite the fact that both theories approach the same theme, different objectives can be characterized depending on the theory that is being used. This fact leads to a data approach divergence that is dependent upon the investigator’s theoretical background.

The effects of "lifting height" and "lifting velocity" on timing and manipulative forces of the precision grip / 体力科学

The effects of“lifting height (2 cm, 6 cm, and 10 cm) ”and“lifting velocity (natural and fast) ”, and influence of reaching action on timing and manipulative forces of the precision grip were examined while lifting a test object. Five adult males volunteered as subjects for the study. Grip forces, load force (the vertical lifting force) and vertical position of the test object were measured and time derivatives of them were computed using laboratory software. It was found that lifting height and velocity exerted significant interaction effects in movement time of the object during lifting phase (T3), peak load force (PLF) and peak velocity (PVel) . Significant main effects of height and velocity were as follows. The higher the lifting height (2 cm, 6 cm, 10 cm) was, the longer T 3 as well as larger PGF, PLF, PdGF/dt, and PVeI were. For the fast velocity trials, T 2 and T 3 were shorter, and PGF, PLF, PdGF/dt, PdLF/dt, and PVeI were larger than the natural velocity condition. The influence of the lifting velocity was stronger in the height of 6, 10 cm than in the height of 2 cm. For all trials with different heights and different velocity, the force rate profiles (dGF/dt and dLF/dt) were continuous, bell-shaped and single-peaked during the loading phase. There was a parallel increase of grip force in relation to an increase of load force. To reveal the height effect further, the target height was unexpectedly changed in some trials at the moment of finger contact with the grip surface. It was found that both timing and force actions were similar to the initial target height condition followed by an apparent correction of gripping and lifting actions to reach the secondary target height.<BR>Results of this study suggest that both lifting height and velocity were important factors to determine the force actions when manipulating an object. Both grip force and load force seem to be well-programmed according to intended height and velocity conditions.<BR>When the lifting action was made following the reaching action, T 3 became shorter, PGF became less, and PVeI became longer than those without the reaching action. The reaching action thus seems to facilitate the force coordination during the lifting action.