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Execution time, kinetics, and kinematics of the mae-geri kick: comparison of national and international standard karate athletes 总被引：1，自引：1，他引：0
Little is known of the performance characteristics of the shotokan karate mae-geri kick. The aim of this study was to compare the execution time, the lower limb kinetics and kinematics, and their respective repeatability in the mae-geri kick of karate athletes of two different standards. Seventeen adult black belt karate competitors (9 national and 8 international athletes) performed six kicks with their dominant lower limb on a striking surface, combining maximum force impact and velocity. Execution time of movement and lower limb kinematics were recorded with a high-speed camera. Maximum force at impact and the forces exerted on the ground were measured using three force plates. The duration of the kick was significantly shorter for international than for national standard athletes. However, no significant difference in the maximum impact force of the kick was observed between the two groups. In addition, significant kinematic differences were observed between the groups, with two angles of motion and one velocity peak occurring sooner in the kick movement for the international athletes, specifically for the knee joint. International athletes also performed the kick with a significantly higher repeatability for duration and kinematics, specifically during the pre-loading phase that precedes the attack phase. We conclude that the duration of the kick and repeatability of lower limb kinematics could be useful in selecting top-level karate athletes and monitoring their training status. 相似文献
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Martinus Buekers Jorge Ibáñez-Gijón Antoine H.P. Morice Guillaume Rao Nicolas Mascret Jerome Laurin 《Quest (Human Kinetics)》2017,69(1):65-79
While the call for interdisciplinary studies has been loud and clear over the last decade or so, the number of interdisciplinary publications in sport sciences is rather limited. One of the reasons for this scarcity is the complexity of the research process itself. Still, the combination and integration of information from different scientific disciplines seems to be important to better explain how elite performance comes about. In this article, we focus on this issue and discuss the advantages of interdisciplinary research for understanding how elite athletes are able to achieve such high-proficiency levels. The first section provides an overview of the studies that investigated elite performance in sports. In the second section, we focus on the issue of interdisciplinarity and illustrate how the ecological–dynamical approach and the concept of dimensional reduction can be used to explain how elite performers cope with the complex nature of sport skills. In the last section, we present a research outline and some practical considerations that can be helpful for researchers who aim to study sport skills from an interdisciplinary perspective. 相似文献
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Classroom and School Predictors of Civic Engagement Among Black and Latino Middle School Youth 
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下载免费PDF全文 Robert J. Jagers Fantasy T. Lozada Deborah Rivas‐Drake Casta Guillaume 《Child development》2017,88(4):1125-1138
This study used short‐term longitudinal data to examine the contributions of democratic teaching practices (e.g., the Developmental Designs approach) and equitable school climate to civic engagement attitudes, beliefs, and behaviors among 515 Black and Latino middle school students (47.9% male). Concurrent experiences of democratic homeroom and classroom practices, and equitable school climate were associated with higher scores on each civic engagement component. The relation between classroom practices and civic attitudes was more robust when school climate was seen as more equitable. Longitudinally, homeroom practices and equitable school climate predicted higher civic attitudes 1 year later. Discussion focuses on civic attitudes and future research on school experiences that support civic engagement among youth of color. 相似文献
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Felipe Mattioni Maturana Arthur Peyrard John Temesi Guillaume Y. Millet 《Journal of sports sciences》2018,36(10):1095-1102
This study compared the responses of two priming exercises of similar fatigue on the adjustment of the oxygen uptake time constant (τV?O2) in cycling. Ten healthy young adults (25 ± 3 yr) performed: three step transitions from a 20-W baseline to the power output (PO) below the gas exchange threshold (MOD, MODPRE); a 3-min bout (P3MIN) at 90% of peak PO (POpeak), followed by MOD (MOD3MIN); and a 6-min bout (P6MIN) at 80% of POpeak, followed by MOD (MOD6MIN). The O2 supply-to-O2 demand ([HHb]/V?O2) ratio was calculated for MODPRE, MOD3MIN, and MOD6MIN. Neuromuscular fatigue was measured isometrically pre- and post-priming exercise. Reductions in maximal voluntary contraction (?29 ± 6 vs ?34 ± 7%) and high-frequency doublet amplitude (?48 ± 13 vs ?43 ± 11%) were not significantly different between P3MIN vs P6MIN, suggesting similar fatigue. τV?O2 for MOD3MIN and MOD6MIN were similar, being ~25% smaller than MODPRE. The [HHb]/V?O2 ratio was significantly greater in MODPRE (1.13 ± 0.12) compared to MOD3MIN (1.02 ± 0.04) and MOD6MIN (1.02 ± 0.04). This study showed that priming exercise of shorter duration and higher intensity, was sufficient to accelerate V?O2 kinetics similarly to that observed subsequent to P6MIN when the muscle fatigue was similar. 相似文献
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Antony G. Philippe Fabio Borrani Guillaume Py Robin Candau 《Journal of sports sciences》2019,37(3):254-261
System theory is classically applied to describe and to predict the effects of training load on performance. The classic models are structured by impulse-type transfer functions, nevertheless, most biological adaptations display exponential growth kinetics. The aim of this study was to propose an extension of the model structure taking into account the exponential nature of skeletal muscle adaptations by using a genetic algorithm. Thus, the conventional impulse-type model was applied in 15 resistance trained rodents and compared with exponential growth-type models. Even if we obtained a significant correlation between actual and modelled performances for all the models, our data indicated that an exponential model is associated with more suitable parameters values, especially the time constants that correspond to the positive response to training. Moreover, positive adaptations predicted with an exponential component showed a strong correlation with the main structural adaptations examined in skeletal muscles, i.e. hypertrophy (R2 = 0.87, 0.96 and 0.99, for type 1, 2A and 2X cross-sectional area fibers, respectively) and changes in fiber-type composition (R2 = 0.81 and 0.79, for type 1 and 2A fibers, respectively). Thus, an exponential model succeeds to describe both performance variations with relevant time constants and physiological adaptations that take place during resistance training. 相似文献
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Guillaume Escalié Nicolas Recoules Sébastien Chaliès Pascal Legrain 《Sport, Education and Society》2019,24(4):390-403
In the French education system, the current curriculum for students from the primary to the end of secondary school is structured around the notion of key competence. A competence can be defined as an integrated and stable network of knowledge and know-how, with normative behaviors, procedures and types of reasoning. However, without a theoretical conceptualization of building and mobilization processes, the components of a competence are considered as isolated and not interconnected. In the health and physical education (HPE) setting, too few empirical studies have analyzed how teachers would contribute to the development of student’s competence. The aim of this forward-looking article grounded on an experiential and cultural framework consists in clarifying and illustrating a conceptualization of the dynamics of development of competences among students considering the teacher activity. This theoretical framework seems to offer heuristic possibilities for the examination of teaching and learning practices which contribute to the development of the key competences, particularly when a competence is read as an experience that integrates multiple dimensions. Based on audio-video recording of PE lessons and self-confrontation interviews with the teacher and a student, the results of the present study strengthen the criticism of the definition of competence emphasizing the relevance to adopt a holistic approach corresponding to the articulation of intertwined resources (i.e. motor, methodological and social) students allocate to act in PE groups. Furthermore, the results show that the competence building depends on various roles students have the opportunity to play in PE (i.e. observer, tutor). Finally, our results underline the importance of identifying the specific characteristics of the teacher activity designed to structure the learning environment to train students to acquire new competences transferable in society. 相似文献
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