Octavio Álvarez

Influence of the distance in a roundhouse kick's execution time and impact force in Taekwondo

Taekwondo, originally a Korean martial art, is well known for its kicks. One of the most frequently used kicks in competition is Bandal Chagui or roundhouse kick. Excellence in Taekwondo relies on the ability to make contact with the opponents trunk or face with enough force in as little time as possible, while at the same time avoiding being hit. Thus, the distance between contestants is an important variable to be taken into consideration. Thirty-one Taekwondo athletes in two different groups (expert and novice, according to experience in competition) took part in this study. The purpose of this study was to examine both impact force and execution time in a Bandal Chagui or roundhouse kick, and to explore the effect of execution distance in these two variables. A new model was developed in order to measure the force exerted by the body on a load. A force platform and a contact platform were used to measure these variables. The results showed that there are no significant differences in terms of impact force in relation to execution distance in expert competitors. Significant and positive correlations between body mass and impact force (p<.01) seem to mean that novice competitors use their body mass to generate high impact forces. Significant differences were found in competitive experience and execution time for the three different distances of kicking considered in the study. Standing at a certain further distance from the opponent should be an advantage for competitors who are used to kick from a further distance in their training.

Effect of Olympic Weight Category on Performance in the Roundhouse Kick to the Head in Taekwondo

Effect of Olympic Weight Category on Performance in the Roundhouse Kick to the Head in Taekwondo In taekwondo, kick performance is generally measured using impact force and time. This study aimed to analyse performance in the roundhouse kick to the head according to execution distance between and within Olympic weight categories. The participants were 36 male athletes divided into three categories: featherweight (n = 10), welterweight (n = 15) and heavyweight (n = 11). Our results show that taekwondo athletes in all weight categories generate a similar relative impact force. However, the results indicate that weight has a large impact on kick performance, particularly in relation to total response time.

Effects of target distance on select biomechanical parameters in taekwondo roundhouse kick

The aim of this study was to investigate the effects of target distance on temporal and impact force parameters that are important performance factors in taekwondo kicks. Forty-nine taekwondo athletes (age = 24.5 ± 5.9 years; mass = 79.9 ± 10.8 kg) were recruited: 13 male experts, 21 male novices, 8 female experts, and 6 female novices. Impact force, reaction time, and execution time were computed. Three-way repeated measure ANOVAs revealed significant ‘distance’ effect on impact force, reaction time, and execution time (p = 0.001). Comparisons between distance conditions revealed that taekwondo athletes kicked with higher impact force from short distance (17.6 ± 7.5 N/kg) than from long distance (13.1 ± 5.7 N/kg) (p < 0.001), had lower reaction time from short distance (498 ± 90 ms) and normal distance (521 ± 111 ms) than from long distance (602 ± 121 ms) (p < 0.001), and had lower execution time from short distance (261 ± 69 ms/m) than from normal distance (306 ± 105 ms/m) or from long distance (350 ± 106 ms/m) (p = 0.003 and p < 0.001, respectively). In conclusion, target distance affected the kick performance; as distance increases, impact force decreased and reaction time increased. Therefore, when reaction to a simple visual stimulus is needed, kicking from a long distance is not recommended, as longer time is required to respond.

Perfil de habilidades psicológicas en taekwondistas universitarios y su relación con el éxito en competición

Se presenta el perfil de habilidades psicologicas y su poder predictivosobre el exito deportivo en taekwondistas universitarios de competicion. Paraello se evaluo una muestra representativa de 89 taekwondistas (50 hombres y39 mujeres) con edades entre 18 y 34 anos (M = 22,2; DT = 3,34) que competianen el Campeonato de Espana Universitario 2011. Se les administro elInventario Psicologico de Ejecucion Deportiva (IPED) y se tomo como variablede exito deportivo el numero de combates ganados durante el campeonato.Los analisis multivariados mostraron diferencias (p < ,05) en relacion al genero(los hombres informan de mayor auto-confianza, control atencional y afrontamientonegativo) y recibir o no entrenamiento psicologico (mayores niveles encontrol visuo-imaginativo, afrontamiento positivo y control actitudinal paralos que entrenaban psicologicamente), no mostrando diferencias entre expertosy no expertos. En cuanto a los analisis correlacionales se encontraron correlacionespositivas entre control visuo-imaginativo, el nivel motivacional, el controlde afrontamiento positivo y el control actitudinal y el exito deportivo, siendoel control visuo-imaginativo (para la muestra total y los hombres) y el nivelmotivacional (para las mujeres) las habilidades predictoras del exito deportivo.Se discuten los resultados y las implicaciones practicas.

Efectos del apoyo a la autonomía del entrenador en taekwondistas españoles de élite

Resumen es: Tomando como marco teorico la Teoria de la Autodeterminacion, en este estudio se examinaron las relaciones entre el apoyo a la autonomia ofrecido por el ...

Barreras percibidas en el desplazamiento activo al centro educativo: fiabilidad y validez de una escala

OBJECTIVE To examine the reliability and validity of a scale to measure perceived barriers to active commuting to school among Spanish young people. METHOD The validity of the scale was assessed in a sample of 465 adolescents (14-18 years) using a confirmatory factor analysis and studying its association with self-reported active commuting to school. The reliability of the instrument was evaluated in a sub-sample that completed the scale twice separated by a one-week interval. RESULTS The results showed that the barriers scale had satisfactory fit indices, and two factors were determined. The first included environment- and safety-related items (α=0.72), while the other concerned planning and psychosocial items (α=0.64). Active commuting to school showed significant correlations with the total score of the barriers scale (rho=-0.27; p <0.001), with the environmental/safety barriers (rho=-0.22; p <0.001), as well as with the planning/psychosocial barriers (rho=-0.29; p <0.001). Test-retest ICCs for the barriers ranged from 0.68 to 0.77. CONCLUSION The developed scale has acceptable validity and good reliability to assess barriers to active commuting to school among Spanish young people.

Transformational leadership in the local police in Spain: a leader-follower distance approach

Based on the transformational leadership theory (Bass, 1985), the aim of the present study was to analyze the differences in leadership styles according to the various leading ranks and the organizational follower-leader distance reported by a representative sample of 975 local police members (828 male and 147 female) from Valencian Community (Spain). Results showed differences by rank (p < .01), and by rank distance (p < .05). The general intendents showed the most optimal profile of leadership in all the variables examined (transformational-leadership behaviors, transactional-leadership behaviors, laissez-faire behaviors, satisfaction with the leader, extra effort by follower, and perceived leadership effectiveness). By contrast, the least optimal profiles were presented by intendents. Finally, the maximum distance (five ranks) generally yielded the most optimal profiles, whereas the 3-rank distance generally produced the least optimal profiles for all variables examined. Outcomes and practical implications for the workforce dimensioning are also discussed.

Tactical Analysis of the Winners' and Non-Winners' Performances in a Taekwondo University Championship

The purpose of this study was to identify tactical characteristics of successful athletes who competed in a National University Championship. Results from the study allow taekwondo coaches and competitors to orient their training towards evidence-based practice to achieve success in competitions. Overall, taekwondo athletes performed more attacks than counterattacks. However, winners performed more counterattacks than non-winners. Moreover, winners performed more anticipatory counterattacks (ANC) and less indirect attacks (INA) than non-winners. Lastly, the order of the performance of the actions for non-winners was by decreasing frequency direct attack (DIA), INA, posterior counterattack (POC), simultaneous counterattack (SIC) and ANC, while for winners the order for most to least frequent action was DIA, INA and POC, followed by SIC and ANC. In conclusion, taekwondo athletes need to focus their trainings on both attacks and counterattacks, with its order of importance being: 1) DIA; 2) INA and POC; and 3) ANC and SIC; to increase the level of their tactical behaviour.

ESTRUCTURACIÓN DE LA ESTRATEGIA PARA ORGANIZAR ACTIVIDADES FÍSICO-DEPORTIVAS Y RECREATIVAS

Resumen es: Existe una amplia evidencia empirica que muestra los beneficios de la actividad fisica sobre la salud fisica y psicologica de los individuos (p.e., Blair...

Relationships Between Personal Values and Leadership Behaviors in Basketball Coaches

Background: Based on the refined theory of basic individual values and transformational leadership theory, this study focuses on the associations between coaches’ value priorities and their transformational leadership behaviors, exploring the potential mediation versus moderation effect of two alternative variables in this relationship: perceived club pressure or an autonomy supportive environment. Methods: Participants were 266 basketball coaches (85.7% men) from 17 to 66 years old (M = 32.82, SD = 9.2) from 119 different Spanish clubs. On average, they had worked for their current sport clubs for 5.02 years, and they had a mean of 11.10 years of experience. The coaches were all Spanish speakers, and they trained players at different levels of competition. Results: The stronger the importance of the coaches’ self-transcendent values (i.e., universalism and benevolence), the more they displayed transformational behaviors (i.e., individual consideration, inspirational motivation, intellectual stimulation, and fostering acceptance of group goals) toward the basketball players and perceived a more autonomy supportive environment and lower pressure from the club. Coaches who held conservation values (i.e., humility and face) displayed inspirational motivation behaviors. When coaches held openness to change values (i.e., stimulation and self-direction thought), they tended to display inspirational motivation and intellectual stimulation. Finally, coaches who held beliefs in self-enhancement values (i.e., power) displayed lower transformational behaviors (intellectual stimulation and fostering acceptance of group goals) toward their basketball players, and they perceived higher pressure from the club and a less autonomy supportive environment. Moreover, the club’s autonomy supportive environment played a mediator role between self-transcendence values and some transformational behaviors; however, moderator effects were not significant, with the exception of coaches with self-enhancement values, who tended to avoid intellectual stimulation to a larger extent when they perceived high levels of pressure at the club. Conclusion: These results highlight the importance of identifying the value base on which to develop transformational leadership programs in order to enhance positive experiences in the sport domain.