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161.
In this study, we develop a finite element model to examine the oblique soccer ball bounce. A careful simulation of the interaction between the ball membrane and air pressure in the ball makes the model more realistic than analytical models, and helps us to conduct an accurate study on the effect of different parameters on a bouncing ball. This finite element model includes a surface-based fluid cavity to model the mechanical response between the ball carcass and the internal air of the ball. An experimental set-up was devised to study the bounce of the ball in game-relevant impact conditions. Ball speed, angle, and spin were measured before and after the bounce, as well as ball deformation and the forces during the impact. The finite element model has been validated with three different sets of data, and the results demonstrate that the finite element model reported here is a valuable tool for the study of ball bounce. After validation of the model, the effect of the friction coefficient on soccer ball bounce was studied numerically. Simulation results show that increasing the friction coefficient may result in reversal of the horizontal impact force. 相似文献
162.
Machado-Rodrigues AM Coelho-E-Silva MJ Mota J Cyrino E Cumming SP Riddoch C Beunen G Malina RM 《Journal of sports sciences》2011,29(14):1503-1514
The agreement between self-reported and objective estimates of activity energy expenditure was evaluated in adolescents by age, sex, and weight status. Altogether, 403 participants (217 females, 186 males) aged 13-16 years completed a 3-day physical activity diary and wore a GT1M accelerometer on the same days. Partial correlations (controlling for body mass) were used to determine associations between estimated activity energy expenditure (kcal · min(-1)) from the diary and accelerometry. Differences in the magnitude of the correlations were examined using Fisher's r to z transformations. Bland-Altman procedures were used to determine concordance between the self-reported and objective estimates. Partial correlations between assessments of activity energy expenditure (kcal · min(-1)) did not differ significantly by age (13-14 years: r = 0.41; 15-16 years: r = 0.42) or weight status (normal weight: r = 0.42; overweight: r = 0.39). The magnitude of the association was significantly affected by sex (Δr = 0.11; P < 0.05). The agreement was significantly higher in males than in females. The relationship between activity energy expenditure assessed by the objective method and the 3-day diary was moderate (controlling for weight, correlations ranged between 0.33 and 0.44). However, the 3-day diary revealed less agreement in specific group analyses; it markedly underestimated activity energy expenditure in overweight/obese and older adolescents. The assessment of activity energy expenditure is complex and may require a combination of methods. 相似文献
163.
The purpose of this study was to examine whether the relationships between contextual factors (i.e., autonomy-supportive vs. controlling coaching style) and person factors (i.e., autonomous vs. controlled motivation) outlined in self-determination theory (SDT) were related to prosocial and antisocial behaviors in sport. We also investigated moral disengagement as a mediator of these relationships. Athletes' (n = 292, M = 19.53 years) responses largely supported our SDT-derived hypotheses. Results indicated that an autonomy-supportive coaching style was associated with prosocial behavior toward teammates; this relationship was mediated by autonomous motivation. Controlled motivation was associated with antisocial behavior toward teammates and antisocial behavior toward opponents, and these two relationships were mediated by moral disengagement. The results provide support for research investigating the effect of autonomy-supportive coaching interventions on athletes' prosocial and antisocial behavior. 相似文献
164.
165.
Roberts Garrett J. Hall Colby Cho Eunsoo Cot Brooke Lee Jihyun Qi Bingxin Van Ooyik Jacklyn 《Educational Psychology Review》2022,34(1):335-361
Educational Psychology Review - This best-evidence synthesis reviews the past 20 years of rigorous reading intervention research to identify effective programs of instruction for Grade K–3... 相似文献
166.
Hoang Loc Phuoc Le Hieu Thanh Van Tran Hung Phan Thanh Chi Vo Duc Minh Le Phuong Anh Nguyen Dung The Pong-inwong Chakrit 《Education and Information Technologies》2022,27(3):4007-4035
Education and Information Technologies - Peer assessment has an important role in teaching and learning nowadays. However, the existing techniques tend to be limited due to a lack of a suitable... 相似文献
167.
Arslan Okan Haser Çiğdem Van Zoest Laura R. 《Journal of Mathematics Teacher Education》2022,25(4):429-452
Journal of Mathematics Teacher Education - To better understand the critical early years of teaching and teacher identity development, this study explored the mathematics teacher identity of two... 相似文献
168.
De Loof Haydée Boeve-de Pauw Jelle Van Petegem Peter 《International Journal of Science and Mathematics Education》2022,20(7):1291-1313
International Journal of Science and Mathematics Education - The “leaky pipeline” with regard to students’ engagement in Science, Technology, Engineering, and Mathematics (STEM)... 相似文献
169.
Harrell Pamela Esprvalo Kirby Benjamin Subramaniam Kartheyan Long Chris 《International Journal of Science and Mathematics Education》2022,20(2):299-320
International Journal of Science and Mathematics Education - This research study investigated conceptions about buoyancy held by 55 elementary preservice teachers enrolled in a science methods... 相似文献
170.
Hsin-Yi Chang Chris Quintana Joseph Krajcik 《Journal of Science Education and Technology》2014,23(3):355-369
In this study, we investigated how students used a drawing tool to visualize their ideas of chemical reaction processes. We interviewed 30 students using thinking-aloud and retrospective methods and provided them with a drawing tool. We identified four types of connections the students made as they used the tool: drawing on existing knowledge, incorporating dynamic aspects of chemical processes, linking a visualization to the associated chemical phenomenon, and connecting between the visualization and chemistry concepts. We also compared students who were able to create dynamic visualizations with those who only created static visualizations. The results indicated a relationship between students constructing a dynamic view of chemical reaction processes and their understanding of chemical reactions. This study provides insights into the use of visualizations to support instruction and assessment to facilitate students’ integrated understanding of chemical reactions. 相似文献