Interpersonal coordination tendencies and perception of visual information for decision-making in futsal.

This study investigated how futsal players visually perceived information on angular interpersonal coordination relations, between available sources such as nearest defender, goalkeeper position and ball, when deciding to shoot at goal. Experienced players (n = 180) participated in eighteen, video-recorded futsal matches, during which 32 participants wore an eye tracking device. Forty-five sequences of play were selected and edited from the moment a teammate passed the ball to the shooter, until the moment a shot was undertaken. Independent variables included the angle connecting the shooter to their closest defender and goalkeeper, and it's rate of change (velocity and variability) during performance. Then eye tracking system (TOBII PRO) was used to examine gaze patterns of shooters during task performance. Findings revealed that: (i) futsal players adapted their gaze patterns differently between key information sources when shooting confirmed as: their closest defender, goalkeeper, ball, and court floor; and (ii), the ball was the information source which was most fixated on, regardless of the characteristics of interpersonal coordination tendencies that emerged when shooting. These findings can be interpreted as evidence of functional perceptual behaviours used to regulate actions needed to ensure precise contact with the ball when shooting at goal. Further, adaptations of fixation patterns, varied between marking defender, goalkeeper, and ball, may provide functional postural orientation to facilitate a successful shot at goal.

The emergence of critical incidents in Rugby Union matches using Markov chain analysis.

During a rugby match, teams are continually trying to cause instabilities of different magnitudes on each other. Once a perturbation occurs, a phase transition emerges. Markov chain analysis has the potential to investigate emerging patterns in rugby union. This study examined the probability of a critical incident (CI; penalties and tries) occurring during Rugby Union matches, and whether differences would exist between winning and losing. The Markov chain analysis was used to identify the probability of a transition from a game state to a further state, due to the analysis of the preceding state. A game phase was defined as a technical and tactical match action which occurred between two consecutive advantage lines. Contingency tables were assembled from 280 phases registered during 11 matches of Brazilian Rugby Union XV A Series Championship. The results showed that previous technical and tactical actions made from rucks had the highest probability of generating a transition phase leading to a CI. The results suggest that the winning teams adopt a more flexible approach to the environmental changes that occur throughout a game and demonstrated more flexibility during transitional state occurrences, with higher variability in technical and tactical actions related to a previous game phase.

The Markov chain analysis showed that previous technical and tactical actions made from rucks had the highest probability of generating a transition phase leading to a CI.Winning teams may adopt a more flexible approach to the environmental changes that occur throughout a game.Higher variability in technical and tactical actions related to a previous game phase was observed in winning teams.The game action leading to CI moments for winning teams involved forwards and backs, while losing teams mainly depended on the involvement of forwards and eventually on opponent errors.Markov chain analysis may be a useful and valid tool to rugby match-play analysis considering the complex system framework.

Instructional Cues in Futsal Teaching, Coaching and Matches / Pistas de instrucción en la enseñanza, entrenamiento y partidos de fútbol sala

This study investigated what are the verbal cues provided in futsal contexts of teaching-learning, training, and official matches, and what are their attentional foci. A cue refers is a short instruction that constrains the students/athletes to direct their attention to critical elements for successful performance. 1543 instructional cues were collected from Physical Education (PE) classes, futsal training sessions and futsal matches of an official championship. Data were analysed based on content analysis method and categorized through the Systematic Analysis of Pedagogical Content Interventions. Inferential analyses were run by the Trend Module (Trend Analysis and Multiple Comparisons) of PEPI software. The results showed that the category offensive technique (passing) was the one with the highest number of instructions in the classes, training and matches. It was also observed that rules and violations were similar between curricular classes and futsal training sessions. The findings allowed to verify (i) the primary cues physical education teachers and coaches provided, (ii) about which critical aspects they referred to and (iii) their specificity regarding the context specificity (classes, training and matches). The findings provide useful insights into the design of instructional tasks as the instructional cues allow students/athletes to gain knowledge about the learning task and to direct their attention to critical elements for successful performance. (AU)

El objetivo de este estudio fue investigar cuáles son las pistas instructivas proporcionadas por los profesores de educación física (EF) en el contexto escolar de enseñanza-aprendizaje. entrenamientos y partidos oficiales del futsal, y sus respectivos focos de atención. Se recogieron 1543 pistas instructivas de las clases curriculares centradas en la enseñanza-aprendizaje de fútbol sala, entrenamientos de fútbol sala y partidos de fútbol sala de un campeonato escolar oficial, en los que participaron cuatro profesores de educación física. Los datos fueron analizados con base en el método de análisis de contenido y categorizados a través del Análisis Sistemático de Intervenciones de Contenido Pedagógico. Los análisis inferenciales fueron ejecutados por el Módulo de Tendencias (Análisis de Tendencias y Comparaciones Múltiples) del software PEPI. Los resultados mostraron que las pistas instructivas de la categoría técnica ofensiva (pases) fueron las más utilizadas en las clases, entrenamientos y partidos. También se observó que las reglas y las violaciones eran similares entre las clases curriculares y los entrenamientos. Los hallazgos permitieron verificar (i) las principales pistas instructivas utilizadas por los profesores de EF, (ii) sobre los aspectos críticos a los que se referían y (iii) su especificidad con respecto al contexto de enseñanza (clases, entrenamientos y partidos). Estos hallazgos brindan información útil sobre el diseño de tareas de instrucción, ya que las pistas instructivas permiten a los estudiantes adquirir conocimientos sobre la tarea de aprendizaje. (AU)

The macro- and micro-adaptations in the football teams

Abstract Aim: This study investigated the adaptations of football teams as hierarchically organised open systems. In this type of system, the collective and individual behaviours are characterised by consistency and variability, respectively. Methods: Five professional men's football matches in the under-20 category were analysed. The team's centroid as a measure of the system's macrostructure and the distance from each player to the team's centroid (a measure of the system's microstructure) were obtained from the players' x and y coordinates of displacement on the soccer field. Cluster analyses were run using Ward's minimum variance method with Euclidean distance. Results: (i) teams showed consistency and variability in their macro- and microstructures, respectively; (ii) there was a correlation between attack and defence patterns in most game sequences; (iii) goals were scored when teams modified their macro and/or microstructure. Conclusion: Football teams showed correspondence in attack-defense patterns with macro-consistency and micro-variability throughout the match. Despite this, there was no relationship between the foregoing patterns and game outcomes. Goals were scored after changes in the team's structure.

Obesity impairs performing and learning a timing perception task regardless of the body position.

Obesity has been associated with poorer sensorimotor performance. However, it remains unclear whether these obesity-related impairments can be mitigated by practice. In the present study, we sought to investigate the effects of practice on performing and learning a temporal estimation task, in women with and without obesity. The experimental task consisted of synchronizing the arrival of two rectangles at a target point. Limited to the pressing of a switch, the task was intended to minimize possible muscular fatigue, self-generated perturbations to balance and the need to accelerate/decelerate body segments. Participants were allowed to choose the displacement velocity of the rectangle they controlled and were informed that they would not be offered any choice over it during a test to come. To control for the effect of different body positions on sensorimotor performance and learning, the 19 women with obesity (BMI = 40.0 + 7.33, age = 44.2 + 6.6) and 20 without obesity (BMI = 22.3 + 1.95, age = 43 + 6.9) were assigned into 4 groups, according to their BMI and body position assumed during practice (standing upright with feet together or sitting). As no significant differences concerning body position were found, the data were reanalysed disregarding this factor. Results revealed that while both groups reduced errors during the Acquisition, participants with obesity showed poorer performance (Acquisition) and sensorimotor learning (Transfer). Given the experimental task and adopted procedures, our results tend to support the hypothesis that hindered perception and/or integration of sensory information is associated with obesity.

The anticipatory and reaction time behaviors of the futsal goalkeeper / Os comportamentos antecipatório e de tempo de reação do goleiro do futsal

ABSTRACT This study aimed to investigate the goalkeeper's anticipatory and reaction time behaviors. For this purpose, 50 kicks performed by male futsal players were analyzed. The time of goalkeeper's response to a kick was analyzed in relation to the kick outcome, court zone and distance between the goalkeeper and player who performed the kick. The goalkeeper's anticipation and reaction time behaviors were those below and above 200 ms as the time criterion, respectively, by considering the moment the player began the preparation for kicking to the moment the goalkeeper began to respond to it. Results showed that the goalkeeper performed anticipatory behaviors predominantly when (i) goals were attained and (ii) kicks were performed in the center and attack court's zones (iii) at a distance ranging from 5.97 to 7.84 meters. In these conditions, the goalkeepers' anticipatory behaviors implied ineffective performances.

RESUMO Este estudo teve como objetivo investigar os comportamentos antecipatório e de tempo de reação do goleiro. Para este fim foram analisados 50 chutes executados por jogaores de futsal. O tempo de resposta do goleiro a um chute foi analisado em relação ao resultado do chute, à zona da quadra e à distância entre o goleiro e o jogador que executou o chute. Os comportamentos de antecipação e tempo de reação do goleiro foram considerados, respectivamente, como aqueles executados abaixo e acima de 200 ms considerando o início do movimento do chutador e o início do movimento do goleiro. Os resultados mostraram que o goleiro executou comportamentos antecipatórios predominantemente quando (i) ocorreram gols, (ii) os chutes foram executados das zonas central e de ataque, (iii) de distâncias entre 5,97 a 7,84 metros. Nestas condições, os comportamentos antecipatórios do goleiro implicaram em performances ineficazes.

Análise das publicações de livros e capítulos de livro dos bolsistas de produtividade em pesquisa do CNPq da área de educação física / Analysis of books and book chapters published by physical education researchers with productivity grants from Brazil's Council for Scientific and Technological Development (CNPq) / Análisis de las publicaciones de libros y capítulos de libro de los becarios de productividad en investigación del CNPq del área de educación física

Resumo O objetivo do estudo foi analisar a produção de livros e capítulos de livro dos bolsistas de produtividade do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) da área da Educação Física (PQ-EF), procurando entender a sua trajetória e verificar tendências das publicações e eventuais alterações nas suas características no período de 1991 a 2016. Foram analisados os currículos dos 91 bolsistas PQ-EF em curso no ano de 2017, no que diz respeito aos livros e capítulos de livro publicados, número de coautores e posição autoral dos bolsistas, por períodos definidos e por categoria de bolsistas. Os resultados mostraram um crescente aumento da produção de livros e capítulos de livro per capita e também um aumento na quantidade de autores por livro e capítulo de livro, sugerindo estratégias de publicação visando ao aumento de produtividade visualizadas na produção de artigos.

Abstract The study analyzes production of books and book chapters by Physical Education (PQ-EF) researchers who held productivity grants from Brazil's National Council for Scientific and Technological Development (CNPq), seeking to understand their trajectory and check trends regarding publications and possible changes in their characteristics in 1991-2016. The curricula of the 91 PQ-EF researchers holding productivity grants in 2017 were analyzed, with regard to books and book chapters, number of co-authors, and position among authors, for defined periods and by grant holder category. The results showed increase in the production of books and book chapters per capita and also in the number of authors per book and book chapter, suggesting publication strategies aimed at increasing productivity seen in production of articles.

Resumen El objetivo del estudio fue analizar la producción de libros y capítulos de libro de los becarios de productividad del Consejo Nacional de Desarrollo Científico y Tecnológico (CNPq) del área de Educación Física (PQ-EF), buscando comprender su trayectoria y verificar las tendencias de las publicaciones y posibles cambios en sus características en el período de 1991 a 2016. Se analizaron los currículos de los 91 becarios PQ-EF en curso en 2017, en lo que se refiere a los libros y capítulos de libro publicados, número de coautores y posición autoral de los becarios, por periodos definidos y por categoría de becarios. Los resultados mostraron un incremento creciente en la producción de libros y capítulos de libro per cápita y también un incremento en la cantidad de autores por libro y capítulo de libro, sugiriendo estrategias de publicación orientadas al aumento de productividad observada en la producción de artículos.

A perceptual cue on a moving opponent improves the learning of a motor skill from aikido / Uma dica perceptiva sobre um oponente em movimento melhora a aprendizagem de uma habilidade motora do aikido

ABSTRACT The effect of different instructional foci on the learning of a motor skill of aikido was investigated. Sixty participants from both sexes with an average age of 14 practiced choku tsuki task, which consisted of hitting a target on the chest of an attacking opponent with a stick. They were divided into four groups: relaxation, with a cue about the relaxed way in which the task should be performed; low hip, with a cue about maintaining hip displacement as low as possible; perceptive, with a cue at the circular target located on the chest of the opponent as they raised their sword to attack; and control, without cues. The dependent variables included measures related to the task goals, movement pattern relative to the task components and kinematic features. Only the perceptive and low hip groups learned the motor skill. The perceptive group obtained better overall performance than the other groups. Learning choku tsuki was improved by the instructional cue "strike target as soon as sword is raised", establishing the learner's perceptive attunement to the moving opponent. Learning was also enhanced by the cue "keep hips as low as possible"; however, at a lower level than that of the perceptive cue.

RESUMO O efeito de diferentes dicas sobre a aprendizagem de uma habilidade motora do aikido foi investigado. Sessenta participantes, de ambos os sexos, com idade média de 14 anos, praticaram a tarefa choku tsuki, que consistia em acertar um alvo no peito de um oponente atacante com um bastão. Eles foram divididos em quatro grupos: relaxamento, com dica sobre a maneira relaxada como a tarefa deveria ser executada; quadril baixo, com dica sobre manter o quadril o mais baixo possível; perceptiva, com dica sobre o alvo circular localizado no peito do oponente enquanto ele levantava a espada para atacar; e controle, sem dicas. As variáveis dependentes incluíram medidas relacionadas aos objetivos da tarefa, padrão de movimento em relação aos componentes da tarefa e características cinemáticas. Apenas os grupos perceptivo e quadril baixo aprenderam a habilidade motora. Ainda, o grupo perceptivo obteve melhor desempenho que os demais grupos. A aprendizagem do choku tsuki foi aprimorada pela dica "estocar o alvo assim que levantar a espada", estabelecendo a sintonia perceptiva do aprendiz com o oponente em movimento. A aprendizagem também foi aprimorada pela dica "mantenha o quadril o mais baixo possível"; no entanto, em um nível inferior ao da dica perceptiva.

Proposta de avaliação de livros e capítulos de livros na área 21 da Capes / Proposal for the evaluation of books and book chapters for Capes area 21 / Propuesta de evaluación de libros y capítulos de libros en el área 21 de la Capes

Resumo O objetivo deste estudo foi propor um modelo de avaliação qualitativa de livros e capítulos de livros com base na percepção da comunidade de docentes da Área 21 da Capes sobre o prestígio das editoras. Noventa orientadores de programas de pós-graduação das diferentes regiões do país responderam a um questionário de avaliação da percepção do prestígio das editoras científicas. A partir do valor da percepção de prestígio, as editoras internacionais (N = 69) e nacionais (N = 97) foram ordenadas e classificadas em decis. Após, propusemos um sistema de classificação de livros e capítulos de livros de oito níveis considerando dois critérios: a) editora internacional ou nacional; e b) decil de cada editora. Os níveis de L1 a L4 referem-se às editoras internacionais (da maior para a menor percepção de qualidade), e os níveis de L5 a L8, às nacionais (da maior para a menor percepção de qualidade).

Abstract This study proposes a system to evaluate books and book chapters based on the perception of graduate program advisers affiliated to Capes (area 21) regarding the prestige of academic publishers. Ninety professors from all Brazilian regions responded to the questionnaire to assess their perception about the prestige of academic publishers. Almost all respondents (94.25%) considered the scientific quality of books as the most critical factor in determining publishers' quality. The prestige value of international (N=69) and national (N=97) publishers were divided into deciles. We proposed an eight-level system to classify books and book chapters based on two criteria: a) their international or national publishers; and b) publishers' deciles. Levels L1 to L4 refer to international publishers (from high to low quality perception), and L5 to L8 refer to national publishers (from high to low quality perception).

Resumen El objetivo de este estudio ha sido proponer un modelo de evaluación cualitativa de libros y capítulos de libros a partir de la percepción de la comunidad de docentes del área 21 de la Capes acerca del prestigio de las editoriales. Noventa orientadores de programas de posgrado de las diferentes regiones del país respondieron un cuestionario para evaluar la percepción del prestigio de las editoriales científicas. A partir del valor de la percepción de prestigio, las editoriales internacionales (N = 69) y nacionales (N = 97) fueron ordenadas y clasificadas en deciles. En seguida, propusimos un sistema de clasificación de libros y capítulos de libros de ocho niveles considerando dos criterios: a) editora internacional o nacional; y b) decil de cada editorial. Los niveles de L1 a L4 se refieren a las editoriales internacionales (de mayor a menor percepción de calidad) y los niveles de L5 a L8 a las nacionales (de mayor a menor percepción de calidad).

The differentiated effect of the task complexity on retention and transfer of stroke survivors.

The aim of this study was to investigate the effects of task complexity on the motor learning of by stroke survivors. Participants (N = 24) performed 150 trials of a simple or complex balance task during three acquisition days. Level of complexity was determined by the number of sequential movements. Outcomes were recorded on pretest, posttest, retention and transfer test. Data were analyzed by considering measures of performance score and movement time. Results showed that only the low complexity group improved the performance from the pretest to posttest and maintained it in the retention test. Performance worsened in both groups from retention to transfer test. The main conclusions were: (i) complex task did not allow learning; (ii) stroke survivors were able to learn a simple task in terms of retention, but not of transfer.

Trends in scientific production by physical education phd student researchers holding productivity grants from Brazil's National Council of Technological and Scientific Development (CNPq) / Tendências da produção científica dos bolsistas de produtividade em pesquisa do CNPq da área de educação física / Tendencias en la producción científica de los becarios de productividad en investigación del CNPq del área de educación física

Este estudo buscou analisar a produção científica dos bolsistas de produtividade do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) da área da Educação Física (PQ-EF), procurando entender a sua trajetória e verificar tendências quanto a publicações de artigos e às eventuais alterações nas suas características no período de 1991 a 2016. Foram analisados os currículos dos 91 bolsistas PQ-EF em curso no ano de 2017, no que diz respeito aos artigos publicados em periódicos, número de coautores e posição na autoria dos artigos, como também a relação entre esses fatores por níveis de bolsa e tempo de término do doutorado. Os resultados revelaram um aumento expressivo da produção científica per capita e também um aumento de publicações multiautorais com número cada vez maior de coautores, sugerindo estratégias de publicação visando ao aumento de produtividade.

This study analyzes the scientific production by Physical Education (PQ-EF) PhD student researchers holding productivity grants from Brazil's National Council of Technological and Scientific Development (CNPq), in order to understand their trajectory and look into publication trends and possible changes in their characteristics in 1991-2016. The curricula of the 91 PQ-EF researchers holding grants in 2017 were analyzed in terms of articles published in journals, number of co-authors, and authors' positions in the articles, as well as how these factors relate according to productivity grant levels and time taken for completing their PhD studies. The results revealed a significant increase in per capita scientific production and also an increase in multi-author publications as well as the number of co-authors, suggesting publication strategies aimed at higher productivity.

Este estudio se propuso analizar la producción científica de los becarios de productividad del Consejo Nacional para el Desarrollo Científico y Tecnológico (CNPq) en el área de Educación Física (PQ-EF), tratando de comprender su trayectoria y verificar las tendencias con respecto a la publicación de artículos y los posibles cambios en sus características en el período de 1991 a 2016. Se analizaron los currículos de los 91 becarios PQ-EF en curso en 2017, en lo que se refiere a los artículos publicados en revistas, el número de coautores y la ubicación en la autoría de los artículos, así como la relación entre estos factores según los niveles de beca y el tiempo de finalización del doctorado. Los resultados revelaron un aumento significativo en la producción científica per cápita y también un aumento en las publicaciones de varios autores, con un número creciente de coautores, lo que sugiere estrategias de publicación destinadas a aumentar la productividad.

No Improvement on the Learning of Golf Putting By Older Persons With Self-Controlled Knowledge of Performance.

The aim of this study was to verify if older adults would benefit from a self-controlled schedule of knowledge of performance (KP) in the motor skill learning. The study's participants included 22 women and 18 men, with an average age of 68 years (SD = 2.95 years). These were divided into two groups: "Self," in which participants had control over when they received KP and "Yoked," in which participants received KP in a paired manner with the Self group. The learning task was golf putting. Results showed that the groups had similar scores for accuracy and consistency of performance. Results also showed that KP requests were more based on bad trials than good trials. It appears that the important variable for motor learning is not who controls the provision of feedback, but also the older adults' ability to use the information.

The influence of the first pass on the volleyball blockers' decision-making / A influência do primeiro passe na tomada de decisão dos bloqueadores do voleibol

ABSTRACT This study examined the information constraining volleyball blockers' decision-making as they attempted to anticipate an opponent's shot. The role of the ball flight information emerging from the interaction between the digger and the setter was investigated. In the first experiment a kinematic analysis of the ball trajectory was run in order to determine its influence on setter's action. In the second experiment players were asked to predict the block location by watching a video involving (i) the complete ball flight or (ii) only the final ball flight. It was verified that the setting occurred more frequently to the outside hitter when setter was far from the net (experiment 1). In addition, it was found that the ball flight information and the setter position guided the blockers anticipation (experiment 2). These findings suggest that the passing information can provide support for blocking anticipation in specific situations in which the ball flight was characterised by high altitudes.

RESUMO O presente estudo examinou a informação que constrange a tomada de decisão dos bloqueadores no jogo de voleibol, referente à antecipação da jogada adversária. Foi investigado o papel da informação do voo da bola, que emerge da interação entre o passador e o levantador. No primeiro experimento foi feita análise cinemática da trajetória da bola para determinar sua influência na ação do levantador. No segundo experimento jogadores tinham que prever o local em que ocorreria o bloqueio, após assistir a dois tipos de vídeo que continham: (i) o voo completo da bola ou (ii) apenas o voo final da bola. Verificou-se que o levantamento ocorreu mais frequentemente para o jogador da posição 2, quando o levantador estava mais distante da rede (experimento 1). Adicionalmente, verificou-se que a informação de voo da bola e a posição do levantador guiaram a antecipação dos bloqueadores em algumas situações (experimento 2). Os achados sugerem que a informação do passe pode fornecer suporte para a antecipação de bloqueadores em situações específicas, nas quais o voo da bola seja caracterizado por grandes alturas.

Motor learning in post stroke subjects: the effects of practice conditions on the temporal synchronization

Abstract AIMS The aim of this study was to investigate the effects of practice schedule on the motor learning of a synchronization timing task in post-stroke subjects. Subjects and METHODS Seventeen post-stroke individuals were assigned to the experimental group and for the control group were selected seventeen healthy individuals. At the acquisition phase, all participants performed 30 trials of a coincident timing task. Nine individuals from each group practiced constantly and eight from each group practiced randomly, with speed changes in the task. Subsequent phases included: 1) immediate transfer test and 2) long term transfer test after 3 days. Data were analyzed in relation to absolute, variable, and constant errors to assess the performance concerning accuracy, consistence, and direction of responses, respectively. RESULTS All groups increased their accuracy through the practice and were able to adapt it in different speeds. The stroke subjects were more variable in their motor responses. There was no effect of the practice schedule on motor learning, regardless the presence or absence of the neurologic damage. CONCLUSION Post stroke individuals were able to learn a synchronizing task and the capacity of adapt their performance after speed perturbation was preserved. There was no effect of the practice schedule on motor learning.

Effects of practice schedule and task specificity on the adaptive process of motor learning.

This study investigated the effects of practice schedule and task specificity based on the perspective of adaptive process of motor learning. For this purpose, tasks with temporal and force control learning requirements were manipulated in experiments 1 and 2, respectively. Specifically, the task consisted of touching with the dominant hand the three sequential targets with specific movement time or force for each touch. Participants were children (N=120), both boys and girls, with an average age of 11.2years (SD=1.0). The design in both experiments involved four practice groups (constant, random, constant-random, and random-constant) and two phases (stabilisation and adaptation). The dependent variables included measures related to the task goal (accuracy and variability of error of the overall movement and force patterns) and movement pattern (macro- and microstructures). Results revealed a similar error of the overall patterns for all groups in both experiments and that they adapted themselves differently in terms of the macro- and microstructures of movement patterns. The study concludes that the effects of practice schedules on the adaptive process of motor learning were both general and specific to the task. That is, they were general to the task goal performance and specific regarding the movement pattern.

Revealing the decision-making of dribbling in the sport of futsal.

This study aimed to investigate why futsal players decide to dribble. For this purpose, we analysed 396 trials comprising the dribbles (n = 132), passes (n = 131) or shots (n = 133), performed by 70 male futsal players. Passing and shooting angles, and interpersonal distance, including their rates of change (velocity and variability), were regarded as measures of interpersonal coordination tendency and a comparison was made among dribbling, passing and shooting situations. In addition, the variables identified as constraints on deciding to dribble were analysed in relation to age categories, dribbling outcomes and futsal court zone. Results revealed that passing and shooting angles, and interpersonal distance showed higher variability in dribbling than in passing and shooting situations. The findings allowed us to conclude that decision-making on dribbling was influenced by the variabilities of passing angles as well as shooting and interpersonal distance, and that success in dribbling was affected by the variability of interpersonal distance. Such variabilities were interpreted concerning their meaning of risk and/or uncertainty in the execution of motor skills.

The effect of learner's control of self-observation strategies on learning of front crawl.

This study investigated the effect of learner's control of self-observation strategies on motor skill learning. For this purpose, beginner and intermediate learner swimmers practised the front crawl. Seventy college students took part in this experiment. They comprised 40 novice learners, both male (n=19) and female (n=21), with an average age of 20.7 years (±0.44), and 30 intermediate learners, both male (n=17) and female (n=13), with an average age of 21.1 years (±0.86). The design involved a pretest (one day), four acquisition sessions (four days), and a retention test (one day). They were divided into three groups: (1) choice, which could choose to watch a video with their best or overall performance during practise; (2) yoked, which were paired to those of the choice group; and (3) control (did not watch any video). The measures included the performance of front crawl and self-efficacy. The results showed that: (1) beginners who chose a type of observation strategy had superior motor skill learning; (2) for intermediate learners, self-observation promoted better motor learning, regardless of the control of choices; (3) self-observation improved self-efficacy beliefs.

Different Faces of Variability in the Adaptive Process of Motor Skill Learning.

This study investigated the variability by considering an action programme as hierarchically organized, which reconciles invariant and variant features of motor skills at the macro- and microstructural level of analysis. It was assumed that invariant aspects of skilled actions express the macrostructure and therefore measures of sequencing, relative size, relative timing, relative force and relative pause time. The microstructure was related to the variant aspects so that total size, total movement time, total force, and total pause time were selected as its measures. These propositions were tested in an experimental design comprised by three learning phases: a stabilisation phase that entailed a given number of trials to achieve the functional stabilization on a graphic task, followed by transfer and retention phases. In the transfer phase, the graphic task was modified to yield different demands upon skill reorganization. Two such modifications demanded parametric changes (i.e. microstructure changes), in which graphic size and drawing speed were altered. Another modification demanded structural alterations (i.e. macrostructure change), in which drawing was changed. Overall, results supported the main predictions by showing that parametric changes in the task affected the microstructure, but did not affect the macrostructure consistently. Furthermore, a structural change affected both macro- and microstructure.

Informational constraints on the emergence of passing direction in the team sport of futsal.

This study investigated compound spatial and temporal measures of interpersonal interactions purported to constrain the emergence of affordances for passing direction in the team sport of futsal. For this purpose, attacker-defender interactions in 37 sequences of play from a futsal competition in which 24 male professional players participated (M=30.04 years, SD=4.10) were filmed and analysed using TACTO software. Relative angle data were used as measures to study coordination tendencies that emerged between players during performance. Results showed that the direction for a pass emerged from relative angles between: (1) the vector from a ball carrier to ball receiver and the vector from the ball carrier to the nearest defender (70°) (p<0.01) and (2) the vector from a ball carrier to ball receiver and the vector from the ball carrier to a ball receiver's nearest defender (31°) (p < 0.01). Furthermore, passing direction was also constrained by temporal information from the emergence of both angles, since the pass was performed to attacker-defender dyads with the highest velocities of these angles (p < 0.05). Results suggested that decisions on selecting the direction of a pass in the team sport of futsal emerged at critical values of these key compound motion measures.

An adaptive process model of motor learning: insights for the teaching of motor skills.

This article presents an outline of a non-equilibrium model, in which motor learning is explained as a continuous process of stabilization and adaptation. The article also shows how propositions derived from this model have been tested, and discusses possible practical implications of some supporting evidence to the teaching of motor skills. The stabilization refers to a process of functional stabilization that is achieved through negative feedback mechanisms. Initially, inconsistent and incorrect responses are gradually reduced, leading to a spatial-temporal patterning of the action. The adaptation is one in which new skills are formed from the reorganization of those already acquired through the flexibility of the system, reorganization of the skill structure, or self-organization. In order to provide learners with competency for adaptation, teachers should (a) guide students to learn motor skills taking into account that the stabilization of performance is just a transitory state that must be dismantled to achieve higher levels of complexity; (b) be clear which parts (micro) compose the skills and how they interact in order to form the whole (macro); (c) manipulate the skills in terms of their temporal, spatial, and/or spatiotemporal dimensions; (d) organize practice initially in a constant way, and then in a varied regimen (random) when the motor skills involve requirements of time and force; and, inversely for motor skills with spatial demands; and (e), provide a moderate frequency of feedback.