POSSIBILITIES OF IMPLICIT MOTOR LEARNING IN LONG JUMP PE PERFORMANCE INVESTIGATED BIOMECHANICALLY

Introduction: Many investigations, e.g., Hay/Nohara (1990) deal with the biomechanics and movement techniques of the long jump. Therefore we obtained information about the best performance and advice on how to achieve this goal. Two main strategies of motor learning are known in long jump training: The first is feedback training, where the athlete consciously tries to adapt his performance according to the ideal. The second aims at changes in movement patterns by special exercises and arrangements, e.g., takeoff (TO) at a lower position. In this situation, the long jump performance adapts to the situation without the athlete being aware of what he is really doing. Although this strategy is often used in long jump training, especially with novices, even the trainer doesn’t really know what the results of this training are. The aim of our study is to investigate the changes of long jump techniques of preparation for TO and TO under conditions of ‘unconscious’ practice. Methods: Three groups of students, each in one special training situation, practiced long jump performance in four training sessions. An additional group (no training) was taken as the control group. Two-dimensional kinematic data on the last three strides and TO were filmed before (pre-test) and after the training phase (post-test). The subject’s movement was described by the time courses of the main joint angles and angular velocities. The analysis of the time-normalized data followed a combination of several statistical methods according to Schöllhorn (1995). Cluster analysis was used to classify the results. Results: Clustering the trials by means of all variables, the analysis shows a separation by individuals at the most general level which is independent of pre- or posttest. The next step of cluster analysis classifies the long jump trials by pre- and post-test. Further subdivision of variables indicates different clusters following the changes in movement patterns under specific training arrangements. Conclusions: Due to the shortness of the analyzed movement, the results of the cluster analysis give information on implicit motor learning in long jump training under special arrangements. The subdivision of variables allows us to identify which parts of long jump performance are trained by the applied training arrangement. Further investigations are necessary to prove that the identified changes are individual and do not follow a universal ‘ideal technique’ in the long jump. References: Schöllhorn, W.I. (1995). Comparison of biomechanical movement patterns by means of orthogonal reference functions. Biomechanics in Sports XII. Budapest, 20-24. Hay, J.G., Nohara, H. (1990). Techniques Used By Elite Long Jumpers In Preparation For Takeoff. J. Biomechanics 23, 229-239

IDENTIFYING INDIVIDUAL MOVEMENT STYLES IN HIGH PERFORMANCE SPORTS BY MEANS OF SELF-ORGANIZING KOHONEN MAPS

INTRODUCTION: Although single case studies are common in more general oriented behavioral sciences (Yin 1988), they are still very rare in sports science. The still lasting preference of group studies in sports science is often connected with the assumption of ‚ideal techniques‘ in the investigated sports disciplin. Wether such an assumption is justifiable biomechanically, should have been investigated in this pilot-study by means of a pattern recognition approach. METHODS: The final throwing phase of 8 male and 19 female javelin throwers was filmed with two highspeed cameras threedimensionally. The male throwers were finalists of the world championship 1987 in Rome, whereas the female group consisted of 10 worldclass heptathletes and 19 javelin specialists with national and international level. From 2 female specialists 10 and 6 throwing trials were filmed in different competitions, respectively. The throwers movements were described physically complete by means of the main joint angles and its angular velocities. Kohonen maps were trained to project these highdimensional individual feature vectors to a low dimensional neuron output space. The euclidian distances between all trajectories in the neuron output space formed the basis for a cluster analysis (Bauer/Schöllhorn 1997). Beside the complete set of variables we seperated the movement into variables of the a) lower and upper body, b) left and right side, and c) angles and angular velocities. RESULTS AND DISCUSSION: The cluster analyses of all variable sets do not display any performance dependance. Clusters of male and female techniques are distinguishable only tendentious in the complete variable group. What we could identify in all sets of variables were the 10 and 6 trials of the two female specialists, respectively, within two seperated clusters. Although both athletes‘ throws had similar thrown distances (55m to 68m), they were not in the same cluster, but were seperated from the others completely. These clusters, even in the subgroups of variables, provide a clear indication for highly individual throwing techniques not only in the whole but also in upper and lower bodies movement as well as in the left and right side movement, and in the angle and angular velocity, respectively. CONCLUSION: The identification of individual throwing styles by means of a duration of 200ms leads to rethink the idea of ideal throwing techniques and its pure imitation in learning strategies. REFERENCES: Bauer, H. U. Schöllhorn, W. (1997). Self-Organizing Maps for the Analysis of Complex Movement Patterns. Neural Processing Letters 5, 193-199. Yin, R. K. (1988). Case Study Research. Newbury Park: Sage Publications. * We would like to acknowledge Dr.Menzel for providing the data

TEMPORAL AND STRUCTURAL CHARACTERISTICS OF DIFFERENT ATTACK TECHNIQUES IN VOLLEYBALL

A process oriented approach was chosen to identify attack techniques in volleyball. Male subjects were filmed with two high speed video cameras while they performed three attack techniques. Subject's movement was described by the time courses of angles and angular velocities of the main joints and analyzed by a procedure including distance measures and cluster analysis. Cluster analysis classified movement pattems of spikes, and top spin shots, by individual while patterns of lobs were mainly grouped by technique criteria. Except for the quick attacker, lobs are identified if only variables are considered that describes the movement of the arm during take off. From a practical view, the results suggest that a defender should focus on the arm of the attacker dUring take off to recognize the attackers intention early

COMPARATIVE ANALYSIS OF THE TAKEOFF IN POLE VAULT AND LONG JUMP BASED ON TIME-CONTINUOUS DATA

A pattern recognition approach based on time-continuous kinematic data was applied to analyze movement patterns of the pole vault and the long jump during takeoff. Altogether, 24 trials of pole vaulters, long jumpers and decathletes were analyzed using a combination of cluster analysis and discriminant analysis methods. Concerning the jumping movement of the legs structural differences between pole vault and long jump patterns as well as individual movement behaviour were identified. The movements of the jumping leg played an important role for the different TO performances

Movement variability emerges in gait as adaptation to task constraints in dynamic environments

Background: Motor variability has been related to motor control playing a functional role in human adaptive behaviours. However, the direction of the relationship between variability and motor control can be unclear. The specific relations that exist between task constraints and movement (re)organization could explain some of this controversy. Research question: This study sought to understand whether manipulation of task constraints result in changes in the magnitude or structure of motor system variability observed in a basic walking task. We also investigated the relationship between performance in achieving task goals and the structure of motor variability. Methods: Twenty volunteers walked around a circular track with binary combinations of 3 task constraints, providing 8 conditions. The manipulated task constraints were: 1) track width; 2) surface stiffness; and 3), walking direction. Performance was analysed using standard deviation (SD) of sacral displacement and its mean velocity (MV). Fuzzy Entropy (FE) and Detrended Fluctuation Analysis (DFA) were used to assess the kinematic variability structure. Results: Individuals showed lower SD and MV walking on the narrower track. These changes were also followed by higher DFA values, indicating a more auto-correlated structure of variability. The foam surface was also associated with an increase in amplitude, velocity and irregularity (FE) of movement. Significance: Results of this study describe how specific task constraints, such as the width of the walking track and the surface stiffness, shape emergent movement coordination patterns as participants search for functional information from the environment to regulate performance behaviors. Changes in variability structure could reveal the search for adaptive strategies during walking. Smaller movement fluctuations and higher velocity in gait patterns are related to greater irregularity and lower autocorrelation in the kinematic variability structure, demonstrating that a specific relationship emerges between system variability and movement performance, which is driven by task constraints

Aprenentatge diferencial aplicat al servei de voleibol en esportistes novells

L’aprenentatge diferencial s’ha mostrat útil per a la millora de determinades habilitats motrius. Els resultats en poblacions novelles contrasten amb les recomanacions basades en la pràctica en condicions de variabilitat o interferència contextual que qüestionen la seva utilitat en l’aprenentatge de noves habilitats. En aquest treball es comparen les modificacions de la velocitat i la precisió del servei en voleibol en aplicar les metodologies d’entrenament per consistència i d’aprenentatge diferencial. Una mostra de 33 participants sense experiència en voleibol es va dividir en tres grups. Dos grups van dur a terme tres setmanes d’entrenament, mentre que el tercer va conformar el de control. Els participants es van avaluar abans i en dues ocasions posteriors. En cada test es va registrar la precisió i la velocitat dels serveis. Dels resultats es destaca la millora tant en precisió com en velocitat dels grups de pràctica. A més a més, el grup d’entrenament diferencial presenta una milloria en la consistència de la precisió, de manera que disminueix l’error variable dels seus assajos. La principal conclusió de l’estudi és que la metodologia de l’entrenament diferencial pot ser una metodologia molt eficaç per a l’aprenentatge del servei en voleibol en poblacions novelles

The role of motor variability in motor control and learning depends on the nature of the task and the individual’s capabilities

Recent studies have found that motor variability is actively regulated as an exploration tool to promote learning in reward and error-based tasks. Based on this functional role of variability, several researches have manipulated motor variability by practicing in order to maximize learning processes. However, the effectiveness of such variable practice as a tool to improve motor performance has shown several controversial results. The present work reviews how the interaction between the features of individuals with different motor capabilities (i.e. experience and brain disorders) and task constraints modulates the relation between motor variability and motor control and learning. Examining how the process of skill learning can be improved by the variability modulation according to individuals’ is not only of theoretical interest, but may also have several practical implications in motor learning and neuro-rehabilitation.Estudios recientes han demostrado que la variabilidad motora es activamente regulada como herramienta de exploración con objeto de incrementar el rendimiento motor tanto en tareas de aprendizaje basadas en la aplicación de recompensas como en la percepción del error. Basándose en este rol funcional de la variabilidad, varios investigadores han manipulado la variabilidad motora al practicar para maximizar los procesos de aprendizaje motor. Sin embargo, la efectividad de la práctica variable como herramienta para la mejora de la ejecución motora, ha mostrado resultados contradictorios en la literatura científica. El presente trabajo revisa cómo la interacción entre las características de individuos con diferentes capacidades motrices (i.e. experiencia y alteraciones neurológicas) y las características de las tareas modulan la relación entre la variabilidad motora, el control y el aprendizaje motor. El estudio de cómo los procesos de aprendizaje motor pueden ser mejorados mediante la manipulación de la carga de variabilidad al practicar no tiene sólo un interés teórico, sino que puede tener implicaciones prácticas en relación al aprendizaje motor o la neuro-rehabilitación

Non-linear tools and methodological concerns measuring human movement variability

In recent years, several works have explored variability using different approaches, trying to describe the variations in motor movement. Traditionally, movement variability was regarded as a system error due to noise of neuromuscular mechanisms, but alternative theories suggest that motor variability seems to reflect a functional behaviour improving motor control and enhancing learning. Controversial results have been reported about variability characteristics and its role in motor control and learning, and several works suggest that the main difficulty lies in how to measure this variability. In this work, we have outlined the most used non-linear tools to assess human variability, their applications, advantages and disadvantages. We have also suggested different methods about how to achieve a multidimensional approximation to motor variability. Finally, we have called attention to some methodological issues frequently reported as important aspects to take into account when measuring human movement variability.En los últimos años, varios trabajos han explorado la variabilidad desde diferentes enfoques con el objetivo de describir las variaciones del movimiento. Tradicionalmente, la variabilidad del movimiento fue considerada un error del sistema causado por el ruido de los mecanismos neuromusculares, pero actualmente, teorías alternativas sugieren que la variabilidad motora parece reflejar un comportamiento funcional que ayuda a mejorar el control del movimiento y el aprendizaje. Sin embargo, existen resultados controvertidos acerca de las características de la variabilidad motora y su rol en el aprendizaje y control motor. En la literatura se ha sugerido que uno de sus principales motivos puede ser las herramientas utilizadas para intenta analizar la variabilidad. En este trabajo hemos realizado un resumen sobre las herramientas no lineales más utilizadas para valorar la variabilidad humana, su aplicación, ventajas e inconvenientes. Además, sugerimos diferentes métodos para obtener una aproximación multidimensional de la variabilidad motora. Finalmente, hemos hecho hincapié en algunos problemas metodológicos que se han considerado importantes a la hora de medir la variabilidad del movimiento humano

THE EVALUATION OF MOTOR COMPETENCE IN TYPICALLY DEVELOPING CHILDREN: AN INTEGRATIVE REVIEW

The development of motor competence (MC) is essential in childhood. In this respect, previous studies have found several positive associations of the MC with physical activity, cardiorespiratory fitness, physical fitness, and perceived physical competence, as well as an inverse association with weight status. The lack of MC during this stage might, therefore, compromise the future adoption of active and healthier lifestyles. This review aimed at listing and examining the different instruments that have been used to evaluate MC in typically developing children, pointing the weakness and strengths from the perspective of Physical Education (PE) teachers. A systematic search of six electronic databases was conducted. Research designs included cross-sectional, longitudinal or experimental/quasi-experimental. Forty-two articles were identified according to the inclusion criteria. A preference for quantitative measures (21 studies) was verified comparatively to a more qualitative approach (13 studies), although eight studies used both measures. Additionally, we have found that 34 studies used standardized protocol tests and eight studies used protocols developed by the authors. In general the protocols exhibited some strong points, however several presented weaknesses that can limit their application in PE classes, such as the excessive amount of time required, the large number of tasks, the ceiling or floor effects, and the fact that not all MC components are simultaneously evaluated. Different instruments and methodologies have been used to evaluate MC. Finally, a quantitative standardized protocol test is suggested, with proper reliability and validity, which can be used by physical education professional

an integrative review

The development of motor competence (MC) is essential in childhood. In this respect, previous studies have found several positive associations of the MC with physical activity, cardiorespiratory fitness, physical fitness, and perceived physical competence, as well as an inverse association with weight status. The lack of MC during this stage might, therefore, compromise the future adoption of active and healthier lifestyles. This review aimed at listing and examining the different instruments that have been used to evaluate MC in typically developing children, pointing the weakness and strengths from the perspective of Physical Education (PE) teachers. A systematic search of six electronic databases was conducted. Research designs included cross-sectional, longitudinal or experimental/quasi-experimental. Forty-two articles were identified according to the inclusion criteria. A preference for quantitative measures (21 studies) was verified comparatively to a more qualitative approach (13 studies), although eight studies used both measures. Additionally, we have found that 34 studies used standardized protocol tests and eight studies used protocols developed by the authors. In general the protocols exhibited some strong points, however several presented weaknesses that can limit their application in PE classes, such as the excessive amount of time required, the large number of tasks, the ceiling or floor effects, and the fact that not all MC components are simultaneously evaluated. Different instruments and methodologies have been used to evaluate MC. Finally, a quantitative standardized protocol test is suggested, with proper reliability and validity, which can be used by physical education professionals.4811-99FE-2ECD | Luis Paulo Rodriguesinfo:eu-repo/semantics/publishedVersio