The purpose of the study was to compare the differences in the kinematics of the instep kick movement in different kick directions in a soccer penalty kick. The significant aspects of the joint movements that influence the kick directions were determined. Eleven female soccer athletes performed the instep kick in two different directions (left and right posts) on an outdoor field. The kinematic data measured from kick techniques were collected using three standard video cameras and a high speed camera (80Hz). All the data was analyzed by paired t-test. There are several variables that are significantly different between the two kick directions. There are only three variables that can predict kick direction significantly: support foot orientation, distance from support heel to the ball center and approach angle. The support foot may be the most useful cue for goalkeepers to predict the ball direction. Other cues may be less helpful because they are difficult to interpret or too subtle to be detected.

The purpose of the study was to compare the differences in the kinematics of the instep kick movement in different kick directions in a soccer penalty kick. The significant aspects of the joint movements that influence the kick directions were determined. Eleven female soccer athletes performed the instep kick in two different directions (left and right posts) on an outdoor field. The kinematic data measured from kick techniques were collected using three standard video cameras and a high speed camera (80Hz). All the data was analyzed by paired t-test. There are several variables that are significantly different between the two kick directions. There are only three variables that can predict kick direction significantly: support foot orientation, distance from support heel to the ball center and approach angle. The support foot may be the most useful cue for goalkeepers to predict the ball direction. Other cues may be less helpful because they are difficult to interpret or too subtle to be detected.

No description available.

No description available.

The purpose of this study was to assess the acute effects of static stretching on foot velocity at impact with a soccer ball. Eighteen Division I female soccer athletes underwent two test conditions separated by 48 hr. Each condition was randomly assigned and began by placing four retro-reflective markers on bony landmarks of the ankle (total of eight markers, four on each ankle). One condition was the no-stretch condition, in which each participant performed a self-paced jog for 5 min as a warm-up, and then sat quietly for 6 min before performing three maximal instep kicks into a net. The second condition was the stretch condition, which was identical to the no-stretch condition, except the participants performed a series of six randomly ordered stretches instead of sitting quietly for 6 min. Three-dimensional motion analysis was used to quantify the resultant velocity of the head of the 5th metatarsal immediately prior to foot impact with a soccer ball. The results of a dependent t test indicated that there was no significant difference between the no-stretch (18.34 ± 1.29 m/s) and stretch conditions (17.96 ± 1.55 m/s; p = .102, d = .3) Based on these findings, acute stretching performed one time for 30 s before maximal instep soccer kicking has no effect on the resultant foot velocity of Division 1A university female soccer players. Pre-event stretching performed in a like manner may best be prescribed at the discretion of the athlete.

Well control is of the utmost importance during drilling operations. Numerous well control incidents occur on land and offshore rigs. The consequences of a loss in well control can be devastating. Hydrocarbon reservoirs and facilities may be damaged, costing millions of dollars. Substantial damage to the environment may also result. The greatest risk, however, is the threat to human life. As technology advances, wells are drilled to greater distances with more complex geometries. This includes multilateral and extended-reach horizontal wells. In wells with inclinations greater than horizontal or horizontal wells with washouts, buoyancy forces may trap kick gas in the wellbore. The trapped gas creates a greater degree of uncertainty regarding well control procedures, which if not handled correctly can result in a greater kick influx or loss of well control. For this study, a three-phase multiphase flow simulator was used to evaluate the interaction between a gas kick and circulating fluid. An extensive simulation study covering a wide range of variables led to the development of a best-practice kick circulation procedure for multilateral and extended-reach horizontal wells. The simulation runs showed that for inclinations greater than horizontal, removing the gas influx from the wellbore became increasingly difficult and impractical for some geometries. The higher the inclination, the more pronounced this effect. The study also showed the effect of annular area on influx removal. As annular area increased, higher circulation rates are needed to obtain the needed annular velocity for efficient kick removal. For water as a circulating fluid, an annular velocity of 3.4 ft/sec is recommended. Fluids with higher effective viscosities provided more efficient kick displacement. For a given geometry, a viscous fluid could remove a gas influx at a lower rate than water. Increased fluid density slightly increases kick removal, but higher effective viscosity was the overriding parameter. Bubble, slug, and stratified flow are all present in the kick-removal process. Bubble and slug flow proved to be the most efficient at displacing the kick.

La création d'un plan de cours nécessite l'élaboration d'exercices de complexité croissante. L'objectif est d'augmenter progressivement la complexité de la tâche pour permettre d'introduire des incertitudes dans les exercices et favoriser l'apprentissage. Le cadre théorique revient sur les notions et définitions de la tâche, de la complexité, de technique sportive, de la complexité de la tâche en EPS et des bases pédagogiques et didactiques de l'enseignement de la savate boxe française. L'objectif de l'auteur est de créer et valider une échelle de mesure de la complexité de la tâche pour le sport savate boxe française. La méthodologie employée sera de valider cet outil grâce à une validation hypothético-déductive de sa forme, une validation contre un outil d'évaluation du niveau technique en savate, une étude de la fidélité dans le temps par mesures répétées et une sensitivité des résultats entre un utilisateur expert et un utilisateur novice. L'échelle est composée de quatre sous échelles qui mesurent la complexité gestuelle ou informationnelle. Les résultats de l'expérience montre que l'on trouve une corrélation entre les résultats de la sous échelle de complexité gestuelle offensive et le niveau de complexité des situations de la progression technique de savate. On trouve aussi des corrélations entre les résultats à la mesure 1 et à la mesure 2, effectués à un mois d'intervalle. Enfin on montre un plus grand nombre de différences significatives entre les résultats de l'étalon et les résultats du novice par rapport à l'expert. Les conclusions sont que l'outil est valide, fidèle dans le temps, mais qu'il nécessite un apprentissage et que le niveau d'expérience peut influencer sur la prise des mesures. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Échelles, Tâche, Complexité, Technique, Complexité de la tâche, Savate boxe française.

Made available in DSpace on 2014-06-11T19:28:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-06Bitstream added on 2014-06-13T19:58:07Z : No. of bitstreams: 1 silva_mg_me_guara.pdf: 891887 bytes, checksum: f0821f5c19c026a3c479d3e2370051df (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O chute no futebol é um gesto técnico bastante estudado, devido a sua importância dentro de uma partida, porém existem algumas lacunas importantes a serem preenchidas, principalmente quanto a sua análise no aspecto quantitativo. Este estudo teve como objetivo encontrar um sistema eficaz de análise dos fatores técnicos intervenientes na performance motora de jogadores de futebol de campo. Neste sentido tornou-se de fundamental importância avaliar parâmetros biomecânicos aplicados durante o chute com o dorso do pé em atletas de categorias de base, a fim de melhorar a performance motora e corrigir falhas não detectadas pela análise qualitativa. Desta forma foi elaborado um sistema de medidas específico, que teve como ponto central da pesquisa, a análise do movimento de chute ao gol. Utilizou-se a cinemetria bidimensional (2D), visando analisar o ângulo formado pelo joelho da perna de apoio; a força de reação do solo ou força vertical (Fv); o COP (centro de pressão) medido pelo equilíbrio do pé de apoio e deslocamento em fases determinantes do chute; e através de acelerômetro, encontrou-se o comportamento da aceleração ou desaceleração produzidas nas fases do movimento de chute. A amostra foi constituída de quatro indivíduos com idades compreendidas entre 16 e 19 anos, atletas da equipe do Resende Futebol Clube, sendo dois da categoria juniores e dois da categoria juvenil. O teste consistiu na execução de chutes com o dorso do pé cujo objetivo foi acertar o alvo posicionado a nove metros do voluntário; o chute caracterizou-se por ser funcional, mas ao mesmo tempo empregando potência. Os resultados encontrados foram coerentes para Fv e aceleração na análise inter-voluntários. Em relação à velocidade alcançada pela bola para inter-voluntários, os resultados apresentaram padrão esperado... / The kick in soccer is a technical gesture extensively studied because of its importance within a game, but there are some important gaps to be filled, specially regarding its analysis on the quantitative aspect. This study aimed to find an effective system of analysis of technical factors involved in motor control performance of soccer players in the field. In this sense has become of paramount importance to assess biomechanical parameters applied during the kick with the instep of the basic categories of athletes, to improve motor performance and to correct errors not detected by qualitative analysis. Thus was developed a system of specific measures, which had as its central point of the research, analysis of the motion of kicking the goal. Kinemetry used the two-dimensional (2D) to evaluate the angle formed by the knee of the supporting leg, the ground reaction force, especifically vertical force (Fv), the COP (center of pressure) measured by the balance of the foot support and decisive shift in phases of the kick, and by accelerometer, found the behavior of acceleration or deceleration produced in the phases of the motion of kick. The sample consisted of four individuals aged between 16 and 19 years, athletes team Resende Football Club, two juniors and two categories of the youth category. The test consisted in the execution of kicks with the instep whose goal was to hit the target positioned at nine meters of the volunteer, the kick was characterized by being functional, but at the same time employing power. The results were consistent for Fv and acceleration parameters between inter-volunteers and the ball speeds were registered according with literature. The results showed the expected pattern, however, COP parameter presented the individual pattern between inter-volunteers and showed same trend for intra- volunteers

Resumo: O chute no futebol é um gesto técnico bastante estudado, devido a sua importância dentro de uma partida, porém existem algumas lacunas importantes a serem preenchidas, principalmente quanto a sua análise no aspecto quantitativo. Este estudo teve como objetivo encontrar um sistema eficaz de análise dos fatores técnicos intervenientes na performance motora de jogadores de futebol de campo. Neste sentido tornou-se de fundamental importância avaliar parâmetros biomecânicos aplicados durante o chute com o dorso do pé em atletas de categorias de base, a fim de melhorar a performance motora e corrigir falhas não detectadas pela análise qualitativa. Desta forma foi elaborado um sistema de medidas específico, que teve como ponto central da pesquisa, a análise do movimento de chute ao gol. Utilizou-se a cinemetria bidimensional (2D), visando analisar o ângulo formado pelo joelho da perna de apoio; a força de reação do solo ou força vertical (Fv); o COP (centro de pressão) medido pelo equilíbrio do pé de apoio e deslocamento em fases determinantes do chute; e através de acelerômetro, encontrou-se o comportamento da aceleração ou desaceleração produzidas nas fases do movimento de chute. A amostra foi constituída de quatro indivíduos com idades compreendidas entre 16 e 19 anos, atletas da equipe do Resende Futebol Clube, sendo dois da categoria juniores e dois da categoria juvenil. O teste consistiu na execução de chutes com o dorso do pé cujo objetivo foi acertar o alvo posicionado a nove metros do voluntário; o chute caracterizou-se por ser funcional, mas ao mesmo tempo empregando potência. Os resultados encontrados foram coerentes para Fv e aceleração na análise inter-voluntários. Em relação à velocidade alcançada pela bola para inter-voluntários, os resultados apresentaram padrão esperado... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The kick in soccer is a technical gesture extensively studied because of its importance within a game, but there are some important gaps to be filled, specially regarding its analysis on the quantitative aspect. This study aimed to find an effective system of analysis of technical factors involved in motor control performance of soccer players in the field. In this sense has become of paramount importance to assess biomechanical parameters applied during the kick with the instep of the basic categories of athletes, to improve motor performance and to correct errors not detected by qualitative analysis. Thus was developed a system of specific measures, which had as its central point of the research, analysis of the motion of kicking the goal. Kinemetry used the two-dimensional (2D) to evaluate the angle formed by the knee of the supporting leg, the ground reaction force, especifically vertical force (Fv), the COP (center of pressure) measured by the balance of the foot support and decisive shift in phases of the kick, and by accelerometer, found the behavior of acceleration or deceleration produced in the phases of the motion of kick. The sample consisted of four individuals aged between 16 and 19 years, athletes team Resende Football Club, two juniors and two categories of the youth category. The test consisted in the execution of kicks with the instep whose goal was to hit the target positioned at nine meters of the volunteer, the kick was characterized by being functional, but at the same time employing power. The results were consistent for Fv and acceleration parameters between inter-volunteers and the ball speeds were registered according with literature. The results showed the expected pattern, however, COP parameter presented the individual pattern between inter-volunteers and showed same trend for intra- volunteers / Orientador: Tamotsu Hirata / Coorientador: Henrique Martins Rocha / Banca: Mauro Pedro Peres / Banca: Luiz Heleno Moreira Duque / Mestre

The eggbeater kick is a skill used frequently in water polo and synchronized swimming to elevate the upper body for shooting, passing, blocking or compete with the opponent for position in the water. The hips, knees, and ankles are involved in creating favourable orientations of the feet so that propulsive forces in the vertical direction can be created. Literature reporting the technique of the eggbeater kick is scarce and limited to description of kinematics or muscle activity. The relationship of the kinematics to the demands on specific muscles has not been established. The purpose of this study was to analyze the kinematics and muscle activity of the water polo eggbeater kick in fatigued and unfatigued states to provide foundational knowledge on which training programs can be based. Twelve water polo players were tested executing the eggbeater kick in the vertical position while trying to maintain as high a position as possible for the duration of the test. The test was terminated when the player could not keep the top of the sternum marker above water. Anthropometric data were collected using the ‘eZone’ method. Three dimensional coordinates for the lower limbs and two dimensional coordinates of the above water top of the sternum marker were obtained. Surface electromyography recorded the muscle activity of the Tibialis Anterior, Rectus Femoris and Biceps Femoris muscles on both legs. Differences between fatigued and unfatigued conditions and between dominant and nondominant sides were tested using a two factor ANOVA with repeated measures. Differences within subjects were also investigated on a subject by subject basis with regard to muscle activity. Results indicated differences for kinematic and muscle activity variables between fatigue levels. The amplitude of anatomic angles and speed of the feet decreased with fatigue. Significant differences were found between dominant and non-dominant sides for the ankle motion. The non-dominant ankle was more inverted and adducted than the dominant ankle during the knee flexion phase of the cycle. The Rectus Femoris muscle had consistent patterns across subjects, while Tibialis Anterior and Biceps Femoris muscles were more subject specific in their responses. The Rectus Femoris and the Biceps Femoris have an agonist/antagonist relationship during knee flexion and extension. The Tibialis Anterior was active for long periods in the cycle while dorsiflexing and inverting the foot. As a consequence activity in these muscles decreased with fatigue. These findings point towards the necessity for players and coaches to address specific motions and muscles during the training of the eggbeater technique. Future work should focus on developing eggbeater kick training programs that address specific strength and flexibility.