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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Kinematic Changes of the Tennis Forehand Ground Stroke as Post Contact Ball Speed Increases

Funk, Merrill D. 04 November 2010 (has links) (PDF)
Neuromuscular and kinematic patterns during the tennis forehand have been studied extensively. However, no one has evaluated potential upper-extremity kinematic changes during the forehand as ball speed increases. The purpose of this study was to evaluate changes in shoulder and trunk kinematics as forehand ball speed increased, in an attempt to better understand how kinematics may promote forehand ball speed. Peak trunk rotation angle, shoulder horizontal abduction/adduction and internal/external rotation angle, and corresponding angular velocities were measured between initial backswing and ball contact during forehands that were performed at three different speeds (50%, 75%, and 100% of maximal post-impact ball speed). Between-speed differences were observed for all dependent variables. Internal humeral rotation velocity increased by 136% (from 477°/s to 1128°/s) while trunk rotation velocity increased by 91% (from 164°/s to 313°/s) and trunk rotation angle increased by only 26% (from 46° to 58°) as forehand ball speed increased from slow to fast. Two primary conclusions can be drawn from these results: (1) trunk and upper arm rotation (adduction and internal rotation) are important to produce forehand ball speed, and (2), increased joint angular velocity may be more important than altered joint position when attempting to produce maximal forehand ball speed.
2

Características dinâmicas e eletromiográficas do forehand e backhand em tenistas: uma perspectiva biomecânica para avaliar o desempenho / ynamic and eletromyographic characteristics of the forehand and backhand in tennis players

Braga Neto, Ludgero 16 April 2008 (has links)
O forehand e o backhand são as técnicas de movimentos mais utilizados no tênis. São golpes técnicos de complexa execução, pois dependem de uma perfeita sincronização temporal entre o movimento da raquete e a trajetória da bola. A literatura especializada demonstra que o posicionamento dos pés é fundamental para gerar potência nestes golpes e registra basicamente dois tipos de forehand quanto ao posicionamento dos pés: forehand open stance (FOS) e forehand square stance (FSS). A técnica de backhand, desde o início da prática da modalidade, apresenta duas maneiras de ser executada: com uma mão (BK1) ou com duas mãos (BK2) segurando o cabo da raquete. Pesquisas científicas específicas nesta modalidade esportiva têm se tornado razoavelmente freqüentes nas últimas duas décadas. O objetivo deste estudo é descrever as características biomecânicas a partir de parâmetros dinâmicos, cinemáticos e eletromiográficos segundo variáveis e músculos relacionados experimentalmente em função da utilização das quatro técnicas descritas acima. Através do conhecimento destas características biomecânicas, pretende-se ainda estabelecer uma relação de dependência quanto às influências no desempenho técnico esportivo. A amostra foi composta por dez indivíduos do sexo masculino, que possuíam domínio das técnicas analisadas. Ao analisarmos os resultados que reúnem as variáveis Biomecânicas estudadas, percebemos que é possível aceitar parcialmente a hipótese inicial de nosso estudo: as técnicas FOS e BK2 demandam maior ativação muscular quando comparadas com as técnicas FSS e BK1, respectivamente. Observando-se ainda os resultados de eletromiografia, verificamos a predominância de valores mais elevados de ativação muscular para as técnicas FOS e BK2 durante a fase pós-impacto, confirmando-se, portanto a hipótese inicial. Porém, durante a fase pré-impacto, os valores mais elevados de ativação muscular foram observados nas técnicas FSS e BK1, contrariando desta maneira a hipótese inicial. Concluímos, portanto, distintos comportamentos entre as duas técnicas de forehand e backhand, principalmente ao analisarmos as fases pré e pós-impacto, o que nos permitiu uma análise técnica detalhada dos gestos esportivos estudados, dada a complexidade estrutural dos mesmos / The forehand and the backhand are the most common movements in tennis. They are technical strokes of complex execution because they depend on perfect temporal synchronization between the racket\'s movement and the ball\'s trajectory. The tennis literature on the subject shows that the feet\'s positioning is crucial to generate power during these strokes. Two kinds of forehand are identified: the forehand open stance (FOS) and the forehand square stance (FSS). The backhand, since its origin, has appeared in two forms: the one-handed grip (BK1) and the two-handed grip (BK2). Scientific research on the subject has been conducted regularly during the two decades. Hence, the aim of this study is to describe the biomechanical characteristics within dynamic, kinematic and electromyographic parameters, and according to variables and experimentally related muscles in relation to the four different tennis techniques. In addition, through knowledge of these biomechanical characteristics, this thesis intends to identify the influences on technical sports performance. The sample was composed of males (n=10) that have mastery of the forehand and backhand strokes. After analyzing the results that evolve Biomechanics variables studied, we realized that it\'s possible to partially accept the initial hypothesis of our study: the forehand open stance and backhand strokes with both hands demand greater muscle activation when they are compared with forehand square stance and backhand stoke with just one hand, respectively. Still, observing the results of electromyography, we verified the predominance of the highest values of muscle activation for forehand open stance and backhand strokes with both hands during the post-impact phase, it\'s, thus, confirming the initial hypothesis. However, during the pre-impact phase, the highest values of muscle activation were observed in the forehand square stance and backhand strokes with one hand, counteracting, in this way, the initial hypothesis. We concluded, therefore, distinct behaviors between the two forehand and backhand strokes, mainly to analyze the pre and post-impact phase, which allowed us a detailed technical analysis of the sportive gestures studied, owing to its structural complexity
3

Efeito da autofala na aprendizagem motora / Effect of self-talk on motor learning

Ferreira, Thiago Rogel Santos 09 December 2013 (has links)
O objetivo deste estudo foi investigar os efeitos da autofala na aprendizagem motora. A tarefa utilizada foi o forehand do tênis de campo. Oitenta e quatro universitários foram divididos em cinco grupos experimentais e um controle (n = 14). Dentre os grupos experimentais um deles utilizou-se de quatro dicas para direcionamento da atenção a elementos-chave da rebatida, os demais fizeram uso de apenas uma das quatro dicas (bola, quique, bater, pronto), já o grupo controle recebeu somente instruções gerais fornecidas a todos os participantes. Na fase de aquisição todos os grupos realizaram 180 rebatidas divididas em 60 por dia. Em seguida, eles realizaram um teste de transferência contendo 10 rebatidas com mudança da direção do outro alvo e, após 5 dias, um teste de retenção contendo 10 rebatidas nas mesmas condições da fase de aquisição. A variável dependente foi o acerto ao alvo localizado na quadra adversária. Os resultados mostraram que todos os grupos melhoraram os desempenhos na fase de aquisição, os quais foram mantidos nos testes de transferência e retenção. Entretanto, não foram encontradas diferenças entre os grupos. Concluiu-se que as aprendizagens do forehand com e sem a autofala apresentaram efeitos similares. E, ainda, que a autofala sobre quatro aspectos da tarefa foi similar àquelas com autofala de apenas um aspecto / The aim of this study was to investigate the effects of self-talk on the motor learning. The task was the forehand of the tennis. Eighty-four students were divided into five experimental groups and one control group (n = 14). One of the experimental groups used four cues for directing attention to key elements of forehand. The other groups have made use of only one of the four cues (ball, bounce, hit, ready), and the control group received only general instructions. In the acquisition phase all groups performed 180 trials which were divided into 60 per day. Then they performed a transfer test of 10 trials involving a shift in the target direction and, after 5 days a retention test was run with ten trials in the same conditions of the acquisition phase. The dependent variable was the hit to the target located in the opponent\'s court. The results showed that all groups improved their performances in the acquisition phase, which were kept in the retention and transfer tests. However, no differences were found between groups. It was concluded that the learning of the forehand with and without self-talk showed similar effects. And, that self-talk of four aspects of the task was similar to those with self-talk of only one aspect
4

Efeito da autofala na aprendizagem motora / Effect of self-talk on motor learning

Thiago Rogel Santos Ferreira 09 December 2013 (has links)
O objetivo deste estudo foi investigar os efeitos da autofala na aprendizagem motora. A tarefa utilizada foi o forehand do tênis de campo. Oitenta e quatro universitários foram divididos em cinco grupos experimentais e um controle (n = 14). Dentre os grupos experimentais um deles utilizou-se de quatro dicas para direcionamento da atenção a elementos-chave da rebatida, os demais fizeram uso de apenas uma das quatro dicas (bola, quique, bater, pronto), já o grupo controle recebeu somente instruções gerais fornecidas a todos os participantes. Na fase de aquisição todos os grupos realizaram 180 rebatidas divididas em 60 por dia. Em seguida, eles realizaram um teste de transferência contendo 10 rebatidas com mudança da direção do outro alvo e, após 5 dias, um teste de retenção contendo 10 rebatidas nas mesmas condições da fase de aquisição. A variável dependente foi o acerto ao alvo localizado na quadra adversária. Os resultados mostraram que todos os grupos melhoraram os desempenhos na fase de aquisição, os quais foram mantidos nos testes de transferência e retenção. Entretanto, não foram encontradas diferenças entre os grupos. Concluiu-se que as aprendizagens do forehand com e sem a autofala apresentaram efeitos similares. E, ainda, que a autofala sobre quatro aspectos da tarefa foi similar àquelas com autofala de apenas um aspecto / The aim of this study was to investigate the effects of self-talk on the motor learning. The task was the forehand of the tennis. Eighty-four students were divided into five experimental groups and one control group (n = 14). One of the experimental groups used four cues for directing attention to key elements of forehand. The other groups have made use of only one of the four cues (ball, bounce, hit, ready), and the control group received only general instructions. In the acquisition phase all groups performed 180 trials which were divided into 60 per day. Then they performed a transfer test of 10 trials involving a shift in the target direction and, after 5 days a retention test was run with ten trials in the same conditions of the acquisition phase. The dependent variable was the hit to the target located in the opponent\'s court. The results showed that all groups improved their performances in the acquisition phase, which were kept in the retention and transfer tests. However, no differences were found between groups. It was concluded that the learning of the forehand with and without self-talk showed similar effects. And, that self-talk of four aspects of the task was similar to those with self-talk of only one aspect
5

Características dinâmicas e eletromiográficas do forehand e backhand em tenistas: uma perspectiva biomecânica para avaliar o desempenho / ynamic and eletromyographic characteristics of the forehand and backhand in tennis players

Ludgero Braga Neto 16 April 2008 (has links)
O forehand e o backhand são as técnicas de movimentos mais utilizados no tênis. São golpes técnicos de complexa execução, pois dependem de uma perfeita sincronização temporal entre o movimento da raquete e a trajetória da bola. A literatura especializada demonstra que o posicionamento dos pés é fundamental para gerar potência nestes golpes e registra basicamente dois tipos de forehand quanto ao posicionamento dos pés: forehand open stance (FOS) e forehand square stance (FSS). A técnica de backhand, desde o início da prática da modalidade, apresenta duas maneiras de ser executada: com uma mão (BK1) ou com duas mãos (BK2) segurando o cabo da raquete. Pesquisas científicas específicas nesta modalidade esportiva têm se tornado razoavelmente freqüentes nas últimas duas décadas. O objetivo deste estudo é descrever as características biomecânicas a partir de parâmetros dinâmicos, cinemáticos e eletromiográficos segundo variáveis e músculos relacionados experimentalmente em função da utilização das quatro técnicas descritas acima. Através do conhecimento destas características biomecânicas, pretende-se ainda estabelecer uma relação de dependência quanto às influências no desempenho técnico esportivo. A amostra foi composta por dez indivíduos do sexo masculino, que possuíam domínio das técnicas analisadas. Ao analisarmos os resultados que reúnem as variáveis Biomecânicas estudadas, percebemos que é possível aceitar parcialmente a hipótese inicial de nosso estudo: as técnicas FOS e BK2 demandam maior ativação muscular quando comparadas com as técnicas FSS e BK1, respectivamente. Observando-se ainda os resultados de eletromiografia, verificamos a predominância de valores mais elevados de ativação muscular para as técnicas FOS e BK2 durante a fase pós-impacto, confirmando-se, portanto a hipótese inicial. Porém, durante a fase pré-impacto, os valores mais elevados de ativação muscular foram observados nas técnicas FSS e BK1, contrariando desta maneira a hipótese inicial. Concluímos, portanto, distintos comportamentos entre as duas técnicas de forehand e backhand, principalmente ao analisarmos as fases pré e pós-impacto, o que nos permitiu uma análise técnica detalhada dos gestos esportivos estudados, dada a complexidade estrutural dos mesmos / The forehand and the backhand are the most common movements in tennis. They are technical strokes of complex execution because they depend on perfect temporal synchronization between the racket\'s movement and the ball\'s trajectory. The tennis literature on the subject shows that the feet\'s positioning is crucial to generate power during these strokes. Two kinds of forehand are identified: the forehand open stance (FOS) and the forehand square stance (FSS). The backhand, since its origin, has appeared in two forms: the one-handed grip (BK1) and the two-handed grip (BK2). Scientific research on the subject has been conducted regularly during the two decades. Hence, the aim of this study is to describe the biomechanical characteristics within dynamic, kinematic and electromyographic parameters, and according to variables and experimentally related muscles in relation to the four different tennis techniques. In addition, through knowledge of these biomechanical characteristics, this thesis intends to identify the influences on technical sports performance. The sample was composed of males (n=10) that have mastery of the forehand and backhand strokes. After analyzing the results that evolve Biomechanics variables studied, we realized that it\'s possible to partially accept the initial hypothesis of our study: the forehand open stance and backhand strokes with both hands demand greater muscle activation when they are compared with forehand square stance and backhand stoke with just one hand, respectively. Still, observing the results of electromyography, we verified the predominance of the highest values of muscle activation for forehand open stance and backhand strokes with both hands during the post-impact phase, it\'s, thus, confirming the initial hypothesis. However, during the pre-impact phase, the highest values of muscle activation were observed in the forehand square stance and backhand strokes with one hand, counteracting, in this way, the initial hypothesis. We concluded, therefore, distinct behaviors between the two forehand and backhand strokes, mainly to analyze the pre and post-impact phase, which allowed us a detailed technical analysis of the sportive gestures studied, owing to its structural complexity
6

Analýza forhendu elitních tenistů ve vybraném utkání / Analysis of the elite tennis playersfor the selected match

Chlumecký, Tomáš January 2018 (has links)
Title: Analysis of the elite tennis players for the selected match Objectives: The aim of the work was to find out the frequency, effectiveness and success of the elite players in the selected French Open 2018 match. This was the final match of this tournament, where i analyzed every forehand. Methods: The analysis was done by observing video recordings of final matches from the French Open 2018. This was a notation analysis. The results were recorded in pre-created tables and then converted to charts. Results: The results show us which player has used the forhend, where the forhend was more successful, more efficient, and in which direction it was played. Keywords: forehand, frequency, efficiency, success rate
7

The Effects Of Rhythm Training On Tennis Performance

Sogut, Mustafa 01 August 2009 (has links) (PDF)
The purpose of the study were / to compare the effects of tennis specific and general rhythm training on the forehand consistency performance, rhythmic competence, tennis playing level and agility performance, and to examine the effects of different tempos on rhythmic competence of tennis players. 30 university students whose mean score of International Tennis Number (ITN) was 7.3 (SD=0.9) were divided randomly into three sub-groups: tennis group (TG), general rhythm training group (GRTG), and tennis-specific rhythm training group (TRTG). Measurement instruments were ITN, Agility Test, Rhythmic Competence Analysis Test (RCAT), and Untimed Consecutive Rally Test (UCRT). A Kruskal-Wallis Test was conducted to calculate possible differences between initial scores and to compare improvement scores of groups. A Mann-Whitney U Test was conducted to determine pairwise comparisons of groups for improvement scores and to analyze RCAT scores for different tempos. Results revealed that participants in both rhythm training groups (GRTG and TRTG) improved their forehand consistency performance and rhythmic competence significantly after training period. Results for the improvement scores indicated that there was significant difference in UCRT (3m) between TRTG and TG and in RCAT (50) between both rhythm training groups and TG. On the other hand, participation to additional rhythm trainings was unable to differentiate tennis playing level and agility performance of groups. There was no significant difference between rhythm training groups for all parameters tested. Results also revealed that synchronization of participants&rsquo / movements with the external stimulus was more precise at fast tempo than at slow tempo.
8

The Effects of Play Pracice on Teaching Table Tennis Forehand Skills

Zhang, Peng 20 August 2008 (has links)
No description available.
9

Vliv povrchu na rozložení zatížení nohy při dynamickém pohybu v tenise / The influence of the surface load distribution of the foot during dynamic movement in tennis

Šebíková, Linda January 2017 (has links)
Title: The influence of the surface load distribution of the foot during dynamic movement in tennis Objectives: The aim of this work is to determine whether there is a change in the force load in the area of the sole of the foot during the forehand strike phase in an open position depending on the type of playing surface. Methods: The research was attended by 10 level I tennis players of ranging from the age of 17 to 28. Each of the players has played tennis for at least two years, train 2 - 3 times a week and has no limb injury in the past 12 months. Using the Pedar-X instrument, changes in the force of the plantar load during the forhend strike phase on clay and Casali surfaces were measured. To evaluate these changes, the contact forces [N] (vertical reaction forces) were measured. First, an intra-individual foot impact assessment on the heel region and forefoot on the clay and Casali surface were performed using graphs of temporal force averages. Secondly, an inter-individual evaluation of the maximum force values in the region of the heel, midfoot, forefoot, hallux and lesser toes and whole feet of the foot was performed using the paired t-test statistical method. Results: The results of the work show that the different surfaces influence the size of the load as well as its plantar...
10

Ovlivnění posturální stability hráčů tenisu věkové kategorie 11- 13 let fyzioterapeutickou intervencí cvičením s Propriomedem / The influence of physiotherapeutic intervention with Propriomed on postural stability of 11-13 years old tennis players

Bednarzová, Barbora January 2018 (has links)
Title: The influence of physiotherapeutic intervention with Propriomed on postural stability of 11-13 years old tennis players Objectives: The main aim of this thesis is objectivize the influence of physiotherapeutic intervention involving exercise with Propriomed on the success of strokes and speed of the swing phase of 11-13 years old tennis players. Methods: Teoretical part is composed like a recherche in which are informations that make base fot the practical part. For the practical part was made experimental study which contains sample of 17 probands in age between 11-13 that are active tennis players for more than 5 years. Pobands was divided into intervention group and control group. Intervention group had training with Propriomed once a week. Main task of study was analysis of succes rate and speed of the swing phase of different tennis shots before and after physiotherapeutic intervention with Propriomed and comparing results of both groups. Results: In beckhand shot was observed statistically significant difference after finishing first intervention. It is possible to claim that training with Propriomed positively influence precision of the backhand shot in a short term. Proband reached the best results of succes rate of forehands after last measurement. From that we could claim that...

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