MECHANICAL ANALYSIS OF THE ROUNDHOUSE KICK ACCORDING TO THE STANCE POSITION. A PILOT STUDY

In taekwondo combats, kick performance can be affected by the stance position. The aim of this study was to analyze mechanical variables in the roundhouse kick in taekwondo according to three stance positions (0º, 45º, 90º). Two high-level athletes participated in the study. Mechanical analysis was measured by two 3-D force plates and an eight-camera motion capture system. Data analyses were processed using Visual 3D software. From the 0º and 45º stance positions athletes kicked in less execution time and total response time than from the 90º stance position (p < 0.05). Moreover, the GRF predicted a high percentage of the variance of performance. Finally, the 0º and 45º stance positions seem more appropiate than the 90º stance position

Polar coordinates in Taekwondo

[EN] In observational methodology, inter‐relational behaviors are relevant for coaches and athletes to know which behaviors are dependent or inexistent while others occur

KINEMATICAL ANALYSIS OF FIVE DIFFERENT KICKS IN TAEKWONDO

The purpose of this study was to identify those foot techniques in taekwondo to the head with the highest potential for success in competition. We compared five of the most frequently used kicks, the round kick, front leg axe kick, clench axe kick, jump spin back kick and jump spin hook kick. Since the right timing and fast movements vastly determine success, we looked at the reaction time, execution time and total response time. Eight high level athletes participated in the study. Three Casio HD cameras operated on 300 Hz were used to record kinematics parameters. A Hybrid II Crash Dummy head (H2D) and neck were instrumented. The one-way ANOVA showed that there were no differences in reaction time while there were differences in the execution time and, as a consequence, in the total time (p < .01) as well

Estudio sobre parámetros mecánicos y autoeficacia física percibida en la patada "Dolio Chagui" de Taekwondo

El taekwondo es un deporte de lucha con golpeo donde se pueden utilizar tanto puños (para golpear al pecho) como piernas (para golpear al pecho y a la cara). Sin embargo, las piernas se utilizan en mayor medida que los puños.Durante el combate, los deportistas mantienen una distancia, denominada distancia de combate o de ejecución, que es clave para el éxito deportivo.Entre las acciones a realizar, el Dolio Chagui o patada circular a la cara, ofrece una mayor posibilidad de puntuar que las patadas dirigidas al pecho.En el presente estudio se analizan diversos parámetros mecánicos en la patada Dolio Chagui de taekwondo. Por otro lado, hemos comenzado a estudiar un parámetro psicológico como es la autoeficacia percibida en taekwondistas. Y además, relacionando las variables psicológicas y las mecánicas, hemos pretendido analizar si la percepción de eficacia física del atleta puede predecir el rendimiento objetivo de los mismos.En el estudio participaron 52 deportistas con un mínimo de 4 años de experiencia en la práctica del taekwondo y una frecuencia de entrenamiento de al menos 3 veces por semana. La muestra se dividió en cuatro grupos según el nivel (expertos y promesas) y según el género (varones y mujeres).En el análisis mecánico se valoraron, desde tres distancias de ejecución, las siguientes variables: fuerza máxima de golpeo, fuerza relativa de golpeo, tiempo de reacción, tiempo de ejecución, tiempo total de respuesta y velocidad media de ejecución. Para ello se utilizó un sistema de adquisición de datos compuesto por una plataforma de fuerzas, una plataforma de contacto, una cinta de leds, un microcontrolador y un PC. En el análisis psicológico se valoró la autoeficacia física percibida utilizando la escala PSE (Ryckman et al., 1982) formada por dos subescalas: la habilidad física percibida y la autopresentación física.Los resultados muestran que la distancia de ejecución condiciona los datos mecánicos de las patadas. En esa línea, independientemente del nivel de los deportistas, los varones golpean con una fuerza máxima mayor que la de las mujeres. Además, la fuerza de golpeo se considera un parámetro mecánico susceptible de mejora por medio del entrenamiento. Asimismo, los deportistas varones considerados expertos, generan mayor fuerza por kilogramo de masa corporal (fuerza relativa de golpeo) que el resto de taekwondistas. Por otro lado, se considera que los deportistas expertos varones, realizan la patada Dolio Chagui con mayor eficacia que el resto de deportistas.En cuanto a los sistemas de valoración utilizados, el sistema de adquisición de datos mecánicos nos permite obtener información cuantificable, comparable y fiable. Por su parte, la utilización de cuestionarios validados como por ejemplo la escala de autoeficacia física percibida, nos permite comparar los resultados con otros deportes, y avanzar en el estudio de taekwondo. En este sentido, los taekwondistas varones se perciben más eficaces físicamente que las mujeres. Sin embargo, a nivel expertos, la percepción de eficacia y habilidad física de varones y mujeres, es similar.Finalmente, el PSE predice algunos parámetros mecánicos como por ejemplo, la velocidad media de ejecución y la fuerza máxima de golpeo, permitiendo relacionar la eficacia percibida con el rendimiento del deportista.Taekwondo is a combat sport well known for its kicks. The most frequently used kicks in competition are roundhouse kicks. This study analyses one of the most common roundhouse techniques, the Dolio Chagui (roundhouse kick to the head).During the combat, one of the major factors that regulate the kick is the execution distance (ED), or combat distance, which may be defined as the horizontal distance between the competitor´s front foot and the objective to be hit.In our study maximum impact force (Fmax), relative impact force (Frel) execution time (TE), reaction time (TR), total time (TT) and execution mean velocity (Vm) in relation to execution distance were measured using a mechanical data acquisition system. On the other side, the physical self-efficacy scale (PSE) by Ryckman et al. (1982) has been used to measure individual perception of self-efficacy in participants.52 taekwondo players participated in the study; they were divided into four groups in function of the level (experts and promises) and the gender (male and female). All the athletes have competition experience of at least 4 years and train for at least 3 hours per week.The results showed that execution distance is influential in mechanical data of the Dolio Chagui. Following this viewpoint, male taekwondo players executed the Dolio Chagui with greater Fmax than female. Therefore, Fmax could be improved by the training. On the base of some mechanical results, expert male taekwondo players executed Dolio Chagui with more efficiency than any other group.Psychological results indicate that males rated higher physical self-efficacy than females. However, similar results were obtained for expert level between males and females.Finally, some mechanical parameters (execution mean velocity and maximum impact force) have been predicted by the PSE. Therefore, it allows establish a relationship between the self-efficacy and the taekwondo players' performance

Auto-eficácia e rendimento do chute circular do taekwondo

Development of self-efficacy scales allows the analysis of athletes’ perceptions and examination of the relationship between perception and performance. The aim of this paper was to: (1) develop a specific self-efficacy scale in a taekwondo task, the roundhouse kick, and (2) analyse the sport performance and its relationship with two self-efficacy scales (specific and general) outcomes according to the athletes’ gender. Forty-three taekwondo athletes (33 male and 10 female) participated in this study. The Physical (PSE) and Specific (RKSES) self-efficacy scales were administered. Performance data (impact force and total response time) were acquired by athletes kicking twice to an instrumented target. Results showed that the specific self-efficacy scale has high reliability and is able to predict sport performance in males and females. Males had higher self-efficacy scores and also higher performance results than females. Females’ taekwondo psychological training should be focus on improving their self-efficacy perception in order to increase their performance in the roundhouse kick. This specific self-efficacy scale for the taekwondo roundhouse kick offers empirical information to coaches, sport psychologists and researchers that allow them to predict athletes’ sport performance in the roundhouse kick.El desarrollo de escalas de autoeficacia permite el análisis de las percepciones de los deportistas y el examen de la relación entre dichas percepciones y el rendimiento. El objetivo de este estudio fue (1) desarrollar una escala específica de autoeficacia para una tarea de taekwondo, la patada circular, y (2) analizar el rendimiento deportivo y su relación con los resultados de dos escalas de autoeficacia (específica y general) en función del género de los deportistas. En el estudio participaron 43 taekwondistas (33 hombres y 10 mujeres). Se administraron las escalas de autoeficacia Física (PSE) y Específica (RKSES). Los datos de rendimiento (fuerza de impacto y tiempo total de respuesta) se obtuvieron mediante el golpeo de los deportistas a un objetivo instrumentado. Los resultados mostraron que la escala de autoeficacia específica tiene una mayor fiabilidad y puede predecir el rendimiento deportivo en hombres y mujeres. Los hombres obtuvieron puntuaciones de autoeficacia y rendimientos más altos que las mujeres. El entrenamiento psicológico de las mujeres debería enfocarse en mejorar su percepción de autoeficacia con el objeto de aumentar su rendimiento en la patada circular. Esta escala específica de autoeficacia para el taekwondo facilita información empírica a entrenadores, psicólogos deportivos e investigadores, que les puede permitir predecir el rendimiento deportivo de los atletas en la patada circular.O desenvolvimento de escalas de auto-eficácia permite a análise das perceções dos atletas e o exame da relação entre as ditas perceções e o rendimento. O objetivo do estudo foi: (1) desenvolver uma escala específica de auto-eficácia para uma técnica do taekwondo: o chute circular; e (2) analisar o rendimento desportivo e a sua relação com os resultados das duas escalas de auto-eficácia (específica e geral), em função do gênero dos atletas. Participaram neste estudo 43 taekwondistas (33 homens e 10 mulheres). Administraram-se as escalas de auto-eficácia Física (PSE) e Específica (RKSES). Os dados de rendimento (força de impacto e tempo total de resposta) foram obtidos mediante o golpe dos esportistas a um objetivo instrumentado. Os resultados mostraram que a escala de auto-eficácia específica tem uma maior fiabilidade e pode prever o rendimento desportivo dos homens e mulheres. Os homens obtiveram pontuações de auto-eficácia e rendimentos mais altos do que as mulheres. O treino psicológico das mulheres deveria se focar em melhorar a sua perceção de auto-eficácia com o objetivo de aumentar o seu rendimento com o chute circular. Esta escala específica de auto-eficácia para o taekwondo facilita a informação empírica dos treinadores, psicólogos desportivos e investigadores, permitindo-lhes prever o rendimento desportivo dos atletas com o chute circular

KINEMATIC ANALYSIS OF A ROUNDHOUSE KICK ACCORDING TO THE STANCE POSITION

The stance position has been pointed out as an important factor that can potentially affect the kick performance, so the stance position can be seen as a constraint for the execution. The aim of this study was to compare kinematic variables in some main instants during the roundhouse kick in taekwondo according to three stance positions (0º, 45º, 90º). Nine experienced athletes participated in the study. Kinematic analysis was measured by two 3D force plates and an eight-camera motion capture system. Data analyses were processed using Visual 3D software. Signifficant differences in kinematic data were found at the beggining of the kick; these differences disappear at the end of the kick. Athletes are able to adapt their technique even if the stance position is different

Detection of behavioural patterns in Olympic male taekwondo athletes

The relationship between athletes’ behaviours is relevant for developing defensive and offensive strategies. Traditionally, sequential analysis has been conducted to assess relationships between two behaviours (one considered as focal and the other as conditioned). The aim of the study was to examine Olympic taekwondo athletes’ behavioural patterns by conducting sequential analyses of tactical actions in bouts. Seventy-five male matches of the London Olympic Games in 2012 were studied to analyse tactical actions: attack (direct and indirect), counterattack (anticipatory, simultaneous and posterior), defensive (cuts, blocks and dodges), and opening actions. A sequential analysis of 2 lags (i.e., actions) in both prospective and retrospective perspectives were conducted by using five focal behaviours (i.e., those considered as tactical scoring actions: direct and indirect attack, anticipatory, simultaneous and posterior counterattacks). The results showed different tactical sequences according to the type of action considered as focal in the analysis. Specifically, direct attacks and simultaneous counterattacks were the most frequently action used in competition. Sequential analyses confirmed the interchangeable pattern of attacking and counterattacking actions. Those analyses can provide an insight for athletes’ patterns and tactical strategy training in taekwondo based on empirical data.Cristina Menescardi is supported by the Conselleria d’Educació, Cultura i Esport of the Generalitat Valenciana under grant VALi+d [ACIF/2014/268]

SAGITTAL COUPLING ANALYSIS IN THE ROUNDHOUSE KICK IN TAEKWONDO

Analysis of coordination in taekwondo has been carried out by heterogeneous methods but no analysis of segment coupling has been done. The aim of this study was to analyse intralimb coordination in the roundhouse kick in taekwondo using Vector Coding. Four experienced (right-footed) female athletes participated in the study. Motion analysis was measured by two 3-D force plates and an eight-camera motion capture system. Data analyses were processed using Visual 3D and Matlab softwares. The prevalant coordination pattern changed throughout the roundhouse kick, with each phase of the movement having a different primary movement pattern

UMA ATUALIZAÇÃO DA LÓGICA INTERNA DE COMPETIÇÃO DO COMBATE NO TAEKWONDO

This manuscript addresses the internal logic of sparring taekwondo, regulated by the World Taekwondo Federation, to explain motor actions used in competitions. A narrative review was conducted on Google Scholar, Scopus, Web of Science, Ebsco, PubMed, ProQuest, and Dialnet databases, guided by structural and functional taekwondo parameters with no limits as to year of publication or language used. The authors describe the various elements that make up the sport’s internal logic such as regulation, space, time, motor communication, roles and sub-roles in addition to the techniques or execution models that explain their special characteristics. This could assist in further examining the characteristics of that sport, defining combat actions, and contextualizing the real competitive situation by adapting tactical taekwondo sequences. Being aware of this sport’s unique characteristics will enable creating the necessary framework to continue research on Olympic-level taekwondo. El objetivo de este manuscrito es abordar la lógica interna del taekwondo de competición regulado por la Federación Mundial de Taekwondo para explicar la acción motriz en la competición. Se realizó una revisión narrativa basada en los parámetros estructurales y funcionales del taekwondo en las bases de datos del Google Scholar, Scopus, Web of Science, Ebsco, PubMed, ProQuest y Dialnet sin limitar el año de publicación ni el idioma. Los autores se refieren a los diversos elementos que componen la lógica interna mencionada, como reglamento, espacio, tiempo, comunicación motriz, roles y subfunciones, además de los modelos de técnica o ejecución, explicando sus particularidades. Esto podría ayudarnos a profundizar en las características del taekwondo, a definir la acción de combate y a contextualizar la situación real de la competición, adaptando las secuencias tácticas del taekwondo. El conocimiento de las particularidades de este deporte permite crear un marco necesario para continuar el trabajo de investigación en el taekwondo olímpico. O objetivo do manuscrito é abordar a lógica interna do taekwondo competição regulamentada pela Federação Mundial do Taekwondo para explicar a ação motora na competição. Uma revisão narrativa foi realizada com base nos parâmetros estruturais e funcionais do taekwondo nos bancos de dados do Google Scholar, Scopus, Web of Science, Ebsco, PubMed, ProQuest e Dialnet, sem limitar o ano de publicação nem o idioma utilizado. Os autores se referem aos diversos elementos que compõem a lógica interna mencionada, como regulação, espaço, tempo, comunicação motora, papéis e subfunções, além dos modelos de técnica ou execução, explicando suas particularidades. Isso poderia nos ajudar a aprofundar as características desse esporte, definir a ação de combate e contextualizar a situação real da competição, adaptando as sequências táticas do taekwondo. O conhecimento das particularidades desse esporte permite criar uma estrutura necessária para continuar o trabalho da pesquisa no taekwondo olímpico.  

Equivalent Frame Model with a Decaying Nonlinear Moment-Curvature of Steel-Reinforced Concrete Joints

A numerical model for the analysis of frame structures that is capable of reproducing the behavior of reinforced concrete (RC) members and steel-reinforced concrete (SRC) members in all steps until collapse by simulating a reduced resistance capacity is presented in this work. Taking into account the solid models obtained in previous research that have been validated by experimental results, moment-curvature graphics were obtained in all steps: elastic, plastic, and post-critical to collapse. Beam models versus 3D models considerably simplified the calculation of frame structures and correctly described both the plastic and post-critical phases. The moment-curvature graph can be used in a simplified frame analysis, from post critical behavior to collapse