966 resultados para Sport Science


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Background: A prerequisite for high performance in motor tasks is the acquisition of egocentric sensory information that must be translated into motor actions. A phenomenon that supports this process is the Quiet Eye (QE) defined as long final fixation before movement initiation. It is assumed that the QE facilitates information processing, particularly regarding movement parameterization. Aims: The question remains whether this facilitation also holds for the information-processing stage of response selection and – related to perception crucial – stage of stimulus identification. Method: In two experiments with sport science students, performance-enhancing effects of experimentally manipulated QE durations were tested as a function of target position predictability and target visibility, thereby selectively manipulating response selection and stimulus identification demands, respectively. Results: The results support the hypothesis of facilitated information processing through long QE durations since in both experiments performance-enhancing effects of long QE durations were found under increased processing demands only. In Experiment 1, QE duration affected performance only if the target position was not predictable and positional information had to be processed over the QE period. In Experiment 2, in a full vs. no target visibility comparison with saccades to the upcoming target position induced by flicker cues, the functionality of a long QE duration depended on the visual stimulus identification period as soon as the interval falls below a certain threshold. Conclusions: The results corroborate earlier findings that QE efficiency depends on demands put on the visuomotor system, thereby furthering the assumption that the phenomenon supports the processes of sensorimotor integration.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Retirement from elite sports requires athletes to cope with adjustments on an occupational, financial, physical, social or emotional level. Research on critical life events (e.g., Filipp & Aymanns, 2010) suggests that benefit finding, defined as “the process of deriving positive growth from adversity” (Cassidy et al., 2014), may have a positive impact on this transition. The present study examined the effects of benefit finding on the quality of adjustment to career termination in the short, middle and long term. Former Swiss elite athletes (N = 290) completed a written survey collecting information on a) their emotional reaction to career termination, b) the amount of adjustment in various respects, c) situational characteristics of their career termination, d) the duration and quality of the transition, and e) their subjective well-being. Using Latent Variable Modelling, finding benefit in career termination was found to have both a direct and an indirect effect on long-term well-being (γ=.18). It predicts favorable emotional reactions to career termination (γ = .53) and less adjustment (γ = -.38) which in turn shortens the transition duration (β = -.15 and β = .55, respectively) and quality (β = -.15), and finally augments well-being (β = .41). The data suggest that a focus on benefit finding in both crisis-prevention and crisis-coping interventions may prove useful to prevent crisis transitions.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Fan violence in the context of football matches has drawn the attention of stakeholders and the media. This phenomenon has also attracted the scientific community’s attention, where research mostly focused on reasons for violence escalation. The Elaborated Social Identity Model (ESIM; Drury & Reicher, 2000) for example focuses on group-interactions and social identities, while the Aggravation Mitigation Model (AM model; Hylander & Guvå, 2010) concentrates on factors contributing to an escalation or a non-escalation of group-violence. However individual perceptions of the different persons involved in potential conflicts have not been sufficiently examined. Beside of that research in domestic football or involving ultrafans is scarce. Especially in Switzerland, there is a lack of research concerning the dynamics of the development or non-development of fan violence. This exploratory study included eight critical situations from the season 2012/2013 of the Swiss premier league to gather data about the perceptions of various persons involved (fans, police officers or security) and the dynamics contributing towards escalation or de-escalation. Fifty-nine narrative interviews were conducted and analysed with interpretative phenomenological analysis (Smith, Flowers, & Larkin, 2009). The individuals involved (fans, police and security personnel) showed groupspecific perceptions and a tendency to stereotype the opponent group. Provocative symbols (balaclavas or riot-gear uniforms) were important for the interpretation of the situation. No escalation occurred when successful communication and sufficient distance between the groups was established. Knowledge about the local fan culture is important, because it influences the perception of legitimacy on the side of the fans. This study improves the understanding of fan violence and is congruent with the ESIM and the AM model. It is suggested to deploy police dialogue teams without riot gear. Their task is to establish direct communication with the fans to facilitate a peaceful ending of a critical situation.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Critical situations (CSs) involving football fans is a well-researched phenomenon with most studies examining factors leading to an escalation of violence (e.g. Braun & Vliegenthart, 2008). However, research so far has fallen short of analysing CSs that do not escalate (e.g. Hylander & Guvå, 2010) as well as establishing observable criteria that constitute such CSs. Granström et al. (2009), for instance, put forward a definition of a CS describing such situations as characterised by a discrepancy between peace and war-making behaviours between police and demonstrators. Still, this definition remains vague and does not provide concrete, defining criteria that can be identified on site. The present study looks beyond fans’ violent acts per se and focuses on these situations with a potentially – but not necessarily - violent outcome. The aim of this preliminary study is to identify observable criteria defining such a CS involving football fans. This focus group comprised of five experts working with football fans in the German-speaking area of Switzerland who discussed observable characteristics of a CS. Inductive content analysis led to the identification of specific criteria such as, “arrest of a fan”, “insufficient distance (<30m) between fans and police” and “fans mask themselves”. These criteria were then assigned to four phases of a CS highlighting the dynamic aspect of this phenomenon: Antecedents, Causes, Reactions, Consequence. Specifically, Causes, Reactions and Consequences are observable on site, while Antecedents include relevant, background information directly influencing a CS. This study puts forward a working definition of a CS that can facilitate the assessment of actual situations in the football context as well as for further research on fan violence prevention and control. These results also highlight similarities with studies investigating fan violence in other European countries while acknowledging unique characteristics of the Swiss German fan culture.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Einleitung Der Zugang zum Sport wird insbesondere in der Kindheit stark durch die Eltern beein-flusst, weshalb die Einstellung der Eltern zum Sport sowie deren Sportaktivitäten hierbei von großer Bedeutung ist (Thiel, Seiberth & Meyer, 2013). Darüber hinaus kann eine er-höhte Sport- und Bewegungsaktivität im familialen Alltag die sportbezogenen Einstellun-gen der Kinder prägen und damit das Sportverhalten im Jugend- und jungen Erwachse-nenalter beeinflussen (Baur, 1989). Im Familienalltag wird den Aspekten Bewegung und Sport ein ganz unterschiedlicher Stellenwert zugesprochen. In dieser Untersuchung soll deshalb der Frage nachgegangen werden, inwiefern sportbezogene Verhaltensmuster in der Familie sich unterscheiden und sich auf die Sportpraxis der Kinder im Jugend- und jungen Erwachsenenalter auswirken. Methode Basierend auf dem sozialisationstheoretischen Ansatz wurden mit Hilfe einer Online-Umfrage in 33 Gemeinden in der deutsch- und französischsprachigen Schweiz Jugendli-che und junge Erwachsene im Alter zwischen 15 und 30 Jahren (n = 3677) zu ihrem aktu-ellen Bewegungs- und Sportverhalten sowie retrospektiv zum Stellenwert des Sports so-wie den Sport- und Bewegungsgewohnheiten in der Familie befragt. Nebst dieser quantita-tiven Untersuchung wurden 13 leitfadengestützte mit Jugendlichen und jungen Erwachse-nen im Alter zwischen 15 und 25 Jahren geführt. Der Schwerpunkt der Befragung war die individuelle Sportpraxis sowie die eigene sowie familiäre sport- und bewegungsbezogene Einstellung. Die Interviewauswertung fand mittels qualitativer Inhaltsanalyse (Mayring, 2002) statt. Ergebnisse und Diskussion Die Ergebnisse zeigen, dass bei derzeit inaktiven Jugendlichen und jungen Erwachsenen der familiäre Stellenwert des Sports (M = 2.49, SD = 1.30) signifikant geringer war als bei den Sportaktiven (M = 3.32, SD = 1.28, F(1, 3042) = 179.08, p < 0.01). Darüber hinaus berichten die derzeit nicht sportaktiven 15- bis 30-Jährigen von einer signifikanten geringe-ren Unterstützung innerhalb ihrer Familien (F(1, 3014) = 170.26, p < 0.01). Die qualitative Auswertung zeigt die unterschiedliche Wahrnehmung und Interpretation der elterlichen Unterstützungsprozesse auf. Nicht nur die Sportaktivität der Eltern, sondern auch die sport- und bewegungsbezogenen Gewohnheiten in der Familie sind offensichtlich für das individuelle Sportverhalten im Jugend- und jungen Erwachsenenalter relevant. Literatur Baur, J. (1989). Körper- und Bewegungskarrieren. Schorndorf: Hofmann. Thiel, A., Seiberth, K., & Mayer, J. (2013). Sportsoziologie. Ein Lehrbuch in 13 Lektionen. Aachen: Meyer & Meyer. Mayring, P. (2002). Einführung in die Qualitative Sozialforschung. Weinheim: Beltz.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Introduction: Although it seems plausible that sports performance relies on high-acuity foveal vision, it could be empirically shown that myoptic blur (up to +2 diopters) does not harm performance in sport tasks that require foveal information pick-up like golf putting (Bulson, Ciuffreda, & Hung, 2008). How myoptic blur affects peripheral performance is yet unknown. Attention might be less needed for processing visual cues foveally and lead to better performance because peripheral cues are better processed as a function of reduced foveal vision, which will be tested in the current experiment. Methods: 18 sport science students with self-reported myopia volunteered as participants, all of them regularly wearing contact lenses. Exclusion criteria comprised visual correction other than myopic, correction of astigmatism and use of contact lenses out of Swiss delivery area. For each of the participants, three pairs of additional contact lenses (besides their regular lenses; used in the “plano” condition) were manufactured with an individual overcorrection to a retinal defocus of +1 to +3 diopters (referred to as “+1.00 D”, “+2.00 D”, and “+3.00 D” condition, respectively). Gaze data were acquired while participants had to perform a multiple object tracking (MOT) task that required to track 4 out of 10 moving stimuli. In addition, in 66.7 % of all trials, one of the 4 targets suddenly stopped during the motion phase for a period of 0.5 s. Stimuli moved in front of a picture of a sports hall to allow for foveal processing. Due to the directional hypotheses, the level of significance for one-tailed tests on differences was set at α = .05 and posteriori effect sizes were computed as partial eta squares (ηρ2). Results: Due to problems with the gaze-data collection, 3 participants had to be excluded from further analyses. The expectation of a centroid strategy was confirmed because gaze was closer to the centroid than the target (all p < .01). In comparison to the plano baseline, participants more often recalled all 4 targets under defocus conditions, F(1,14) = 26.13, p < .01, ηρ2 = .65. The three defocus conditions differed significantly, F(2,28) = 2.56, p = .05, ηρ2 = .16, with a higher accuracy as a function of a defocus increase and significant contrasts between conditions +1.00 D and +2.00 D (p = .03) and +1.00 D and +3.00 D (p = .03). For stop trials, significant differences could neither be found between plano baseline and defocus conditions, F(1,14) = .19, p = .67, ηρ2 = .01, nor between the three defocus conditions, F(2,28) = 1.09, p = .18, ηρ2 = .07. Participants reacted faster in “4 correct+button” trials under defocus than under plano-baseline conditions, F(1,14) = 10.77, p < .01, ηρ2 = .44. The defocus conditions differed significantly, F(2,28) = 6.16, p < .01, ηρ2 = .31, with shorter response times as a function of a defocus increase and significant contrasts between +1.00 D and +2.00 D (p = .01) and +1.00 D and +3.00 D (p < .01). Discussion: The results show that gaze behaviour in MOT is not affected to a relevant degree by a visual overcorrection up to +3 diopters. Hence, it can be taken for granted that peripheral event detection was investigated in the present study. This overcorrection, however, does not harm the capability to peripherally track objects. Moreover, if an event has to be detected peripherally, neither response accuracy nor response time is negatively affected. Findings could claim considerable relevance for all sport situations in which peripheral vision is required which now needs applied studies on this topic. References: Bulson, R. C., Ciuffreda, K. J., & Hung, G. K. (2008). The effect of retinal defocus on golf putting. Ophthalmic and Physiological Optics, 28, 334-344.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Einleitung: Die Nachwuchsarbeit im Schweizer Fussball ist seit 1995 stark professionalisiert worden, was sich in den letzten 15 Jahren in mehrere internationale Erfolge niedergeschlagen hat. Im Hinblick auf den sportlichen Erfolg hat sich dabei gezeigt, dass sich die Karrieren der erfolgreichsten Schweizer Spieler, deren Förderung in die ersten Jahre dieser Professionalisierung fällt, bereits in der Sampling Phase (Coté, 1999) durch eine frühe Spezialisierung beschreiben lässt (Zibung & Conzelmann, 2013). Die Trainingsumfänge beinhalten v.a. Clubtraining und viel freies Spiel ausserhalb des Clubs oder fussballnahe andere sportliche Aktivitäten. In diesem Beitrag wird der Frage nachgegangen, inwiefern sich die in den folgenden Jahren nochmals akzentuierte Professionalisierung auf die sportlichen Karrieren der aktuellen Generation von talentierten Fussballspielern ausgewirkt hat. Methode: N = 32 Juniorennationalspieler mit mind. 1 Aufgebot in die U15 oder U16 Nationalmannschaft (Jg. 99; Stichprobe A) werden mit n = 151 ehemaligen Juniorennationalspielern (Jg. 81-87; Stichprobe B aus Zibung & Conzelmann, 2013) in Bezug auf relevante Indikatoren zur Frühspezialisierung verglichen. Dafür wurden die beiden Stichproben in Anlehnung an Zibung und Conzelmann (2013) mittels t-Tests (p < .05) bezüglich folgender Indikatoren für Frühspezialisierung verglichen: Alter beim Beginn freies Fussballspiel und beim ersten Clubeintritt, Trainingsstunden im Club, freies Fussballspiel sowie sportliche Aktivitäten neben dem Fussball (jeweils bis 12-jährig). Die Variablen wurden in beiden Studien retrospektiv per Fragebogen erfasst. Resultate: Die Spieler der jüngeren Generation haben bis 12 Jahre weniger Stunden frei Fussball gespielt (MA = 2016.6, SDA = 1107.1) als die Spieler der älteren Generation (MB = 2535.5, SDB = 1277.3) (t(50.1) = 2.34, p = .02, d = .66). Gleichzeitig haben sie neben dem Fussball weniger andere sportliche Aktivitäten aufzuweisen (t(68.0) = 2.53, p = .01, d = .61). In den Variablen Trainingsstunden im Club (MA = 923.0, SDA = 166.6; MB = 967.0, SDB = 287.1), Alter beim Beginn des freien Fussballspiels (MA = 4.08, SDA = 1.5; MB = 4.36, SDB = 1.2) und beim ersten Clubeintritt (MA = 5.75, SDA = 1.0; MB = 6.07, SDB = 1.3) unterscheiden sich die beiden Stichproben nicht. Diskussion: Der Vergleich der beiden Stichproben zeigt, dass es in den letzten 15 Jahren zu einer Veränderung der Trainingsumfänge von Juniorennationalspielern gekommen ist. Die aktuelle Generation von Juniorennationalspielern spielt neben dem Clubtraining weniger frei Fussball und betreibt aber auch weniger andere Sportarten als die Juniorennationalspieler vor 10-15 Jahren. Ob vermehrte schulische Anforderungen diesen Rückgang in der generellen sportlichen Aktivität verschulden, müsste in der Folge weiter untersucht werden. Ebenso bleibt offen, ob die Einschätzung der Stichprobe B, aufgrund des relativ langen Zeitraums, der zwischen der Erhebung und dem zu erfassenden Zeitraum liegt, zu einer Antwortverzerrung und damit einer Erhöhung der geschätzten Trainingsstunden geführt hat. Literatur: Côté, J. (1999). The influence of the family in the development of talent in sport. The Sport Psychologist, 13 (4), 395–417. Zibung, M. & Conzelmann, A. (2013). The role of specialisation in the promotion of young football talents: A person-oriented study. European Journal of Sport Science, 13 (5), 452–460.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The aim of this study was to examine the acute effects of endurance exercise on jumping and kicking performance in young soccer players. Twenty-one top-class young soccer players (16.1±0.2 years) performed a countermovement jump test and a maximal instep soccer kick test before and after running for 20 min on a treadmill at 80% of their individual maximum heart rate. Two force platforms were used to obtain the following parameters during the countermovement jump: jump height, maximum power, maximum power relative to body mass, maximum vertical ground reaction force, maximum vertical ground reaction force relative to body mass, and maximum vertical ground reaction force applied to each leg. Maximum vertical ground reaction force and maximum vertical ground reaction force relative to body mass applied to the support leg during the kicks were also calculated with a force platform. The kicking motion was recorded using a three-dimensional motion-capture system. Maximum velocity of the ball, maximum linear velocity of the toe, ankle, knee and hip, and linear velocity of the toe at ball contact during the kicks were calculated. Non-significant differences were found in the parameters measured during the countermovement jump and the maximal instep soccer kick test before and after running, suggesting that the jumping and kicking performances of top-class young soccer players were not significantly affected after 20 min treadmill running at 80% of their individual maximum heart rate.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The aim of the present work is to examine the differences between two groups of fencers with different levels of competition, elite and medium level. The timing parameters of the response reaction have been compared together with the kinetic variables which determine the sequence of segmented participation used during the lunge with a change in target during movement. A total of 30 male sword fencers participated, 13 elite and 17 medium level. Two force platforms recorded the horizontal component of the force and the start of the movement. One system filmed the movement in 3D, recording the spatial positions of 11 markers, while another system projected a mobile target over a screen. For synchronisation, an electronic signal enabled all the systems to be started simultaneously. Among the timing parameters of the reaction response, the choice reaction time (CRT) to the target change during the lunge was measured. The results revealed differences between the groups regarding the flight time, horizontal velocity at the end of the acceleration phase, and the length of the lunge, these being higher for the elite group, as well as other variables related to the temporal sequence of movement. No significant differences have been found in the simple reaction time or in CRT. According to the literature, the CRT appears to improve with sports practice, although this factor did not differentiate the elite from medium-level fencers. The coordination of fencing movements, that is, the right technique, constitutes a factor that differentiates elite fencers from medium-level ones.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

El análisis de la velocidad de carrera mediante sensores láser permite la obtención de datos en tiempo real siendo ventajosos frente a otros sistemas. El objetivo de este estudio fue valorar la validez y fiabilidad del sensor láser del sistema BioLaserSport® para el cálculo de velocidades medias y máximas mediante estadísticos relativos y absolutos. Los participantes fueron 17 varones (20.85 ± 1.54 años). Se utilizó un sensor láser tipo 1 (LDM301, Jenoptik, Germany) que registró posiciones de los deportistas a 2000 Hz. Los datos se trataron con la rutina DSL-30 creada con DasyLab v.10.0. Para la validación se utilizó un sistema de fotogrametría-2D con una cámara de alta velocidad (Exilim High Speed EX-F1, Casio) y SkillSpector v.1.3.2. (Video4coach, Grubbemollevej). Además, se utilizaron foto-células de doble haz (Polifemo Light, Microgate, Italy) y un cronómetro Racetime2 (Microgate, Italy). Se registraron, durante dos días, tres series de 30 m de carrera a máxima velocidad. El sensor láser proporcionó, con relación a la fotogrametría, diferencias en las velocidades medias y máximas de -0.11 m•s-1 y 0.14 m•s-1, respectivamente, con unos coeficientes de correlación superiores a 0.86, y mayores de 0.92 con las foto-células para las velocidades medias. Este mostró una excelente fiabilidad test-retest para las velocidades medias con un coeficiente de correlación intraclase (ICC) entre 0.7-0.9 y un error estándar de la media (SEM y SEM%), intrasesión e intersesión, menor de 0.05 m•s-1 y 0.12 m•s-1, respectivamente, y menores de 0.75% y de 2%, respectivamente. Para las velocidades máximas,los valores fueron menores de 0.10 m•s-1 y 0.17 m•s-1, respectivamente, y en ambos casos menores a 1.36% y 1,89%. El láser fue capaz de identificar mínimos cambios detectables (MDC y MDC%) intrasesión, para ambas variables, menores a 0.14 m•s-1 y 0.29 m•s-1, respectivamente (< 2.09% y < 3.76%) e intersesión, menores de 0.34 m•s-1 y 0.47 m•s-1 (< 5.56% y < 5.25%), respectivamente. En consecuencia, es un instrumento útil para el análisis de la evolución de la velocidad intrasujeto y entre sujetos en la carrera de velocidad entre 0-30 m, proporcionando resultados en tiempo real, pero se han de considerar los SEM, SEM%, MDC y MDC% para valorar la mejora del rendimiento.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Correlación entre adherencia a la dieta y el ejercicio en programas de perdida de peso en función del sexo

Relevância:

60.00% 60.00%

Publicador:

Resumo:

¿Influye el índice de masa corporal, el sexo, el tratamiento y la edad en la pérdida de peso?

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Importancia del ejercicio en un tratamiento de pérdia de peso

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Relación entre los cambios de las variable hematolóicas y la capacidad aeróbica