Dynamics of the martial arts high front kick     

Henrik S⊘rensen  Morten Zacho  Erik B. Simonsen  Poul Dyhre‐Poulsen  Klaus Klausen 《Journal of sports sciences》2013,31(6):483-495

Fast unloaded movements (i.e. striking, throwing and kicking) are typically performed in a proximo‐distal sequence, where initially high proximal segments accelerate while distal segments lag behind, after which proximal segments decelerate while distal segments accelerate. The aims of this study were to examine whether proximal segment deceleration is performed actively by antagonist muscles or is a passive consequence of distal segment movement, and whether distal segment acceleration is enhanced by proximal segment deceleration. Seventeen skilled taekwon‐do practitioners were filmed using a high‐speed camera while performing a high front kick. During kicking, EMG recordings were obtained from five major lower extremity muscles. Based on the kinematic data, inverse dynamics computations were performed yielding muscle moments and motion‐dependent moments. The results indicated that thigh deceleration was caused by motion‐dependent moments arising from lower leg motion and not by active deceleration. This was supported by the EMG recordings. Lower leg acceleration was caused partly by a knee extensor muscle moment and partly by a motion‐dependent moment arising from thigh angular velocity. Thus, lower leg acceleration was not enhanced by thigh deceleration. On the contrary, thigh deceleration, although not desirable, is unavoidable because of lower leg acceleration.  相似文献   

Who's Responsible for the Digital Divide? Public Perceptions and Policy Implications     

Dmitry Epstein  Erik C. Nisbet  Tarleton Gillespie 《The Information Society》2013,29(2):92-104

Addressing the reasons for—and the solutions to—the “digital divide” has been on the public agenda since the emergence of the Internet. However, the term has meant quite different things, depending on the audience and the context, and these competing interpretations may in fact orient toward different policy outcomes. The goals of this article are twofold. First, the authors unpack the term “digital divide” and examine how it has been deployed and interpreted across a range of academic and policy discourses. Second, through a framing experiment embedded within a nationally representative survey, the authors demonstrate how presenting respondents with two different conceptual frames of the digital divide may lead to different perceptions of who is most accountable for addressing the issue. From this, they discuss the dynamic relationship between the construction and communication of policy discourse and the public understanding of the digital divide, as well as implications for effective communication about the digital divide and information and communication technology policy to the general public.  相似文献   

The Debate     

Erik P. Bucy 《The Information Society》2013,29(5)

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The relation between individual interest and knowledge acquisition          下载免费PDF全文

Jerome I. Rotgans  Henk G. Schmidt 《British Educational Research Journal》2017,43(2):350-371

The objective of this study was to examine how individual interest and knowledge acquisition are causally related. Three hypotheses were tested using a cross‐lagged panel analysis (N = 186) and two quasi‐experimental studies (N = 68 and N = 108) involving students from schools in Singapore. The first hypothesis is the broadly shared standard assumption on the relation between individual interest and knowledge: the more an individual is interested in a topic, the more (s)he is willing to engage in learning. An alternative hypothesis assumes that individual interest is not the cause but the consequence of the process of learning: individual interest as an affective by‐product of learning. Finally, a third possibility is that interest and knowledge influence each other reciprocally. The results supported the affective‐by‐product hypothesis. Our findings seem at variance with commonly held conceptions that being interested guides knowledge attainment. The implications of these findings for interest research are discussed.  相似文献   

Recollection of a mentor     

Hans Erik Wennberg 《TechTrends》2003,47(1):2-3

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Affordances of teacher professional learning in secondary schools     

Wilfried Admiraal  Joke Kruiter  Ditte Lockhorst  Wouter Schenke  Henk Sligte  Ben Smit 《Studies in Continuing Education》2016,38(3):281-298

It is commonly understood that teachers in secondary school should develop throughout their career in order to stay as an essential factor in student learning. Schools can offer opportunities to link teachers’ professional learning to their school practice with a positive impact on teachers’ motivation to learn and the effectiveness of their learning. In this field study, teachers, school leaders, policy-makers, educational consultants and educational scholars were asked for their perceptions of conditions for teacher learning in school and of interventions in school to enhance teacher professional learning. These conditions and interventions were understood as affordances in schools that enable and support teacher professional learning. The main affordance in school these stakeholders mentioned was an open, but critical way in which teachers share their practices, collaborate and reflect upon their teaching practice. Collaborative practices seem to stimulate many interventions of teacher professional learning in school. Two implications of this finding are discussed. First, we suggest that the maximum teaching time should be reduced, team teaching should be more implemented or classes should be scheduled in such a way that teachers can meet. Second, distributed leadership approaches match with our findings about the role of school leaders in teacher professional learning.  相似文献   

Learning from instruction: the case of mathematics     

Erik De Corte 《Learning Inquiry》2007,1(1):19-30

Starting from a brief analysis of adaptive competence in mathematics, this article describes a series of research-based characteristics of the kind of learning processes that should be elicited in students to facilitate and support in them the progressive acquisition of such competence. Four major characteristics are discussed in some detail: learning is constructive, self-regulated, situated or contextual, and collaborative. A rather new approach to transfer of learning is then presented in which transfer is conceived as the preparation for future learning. Throughout the article it is argued that, notwithstanding the progress made in research on learning from instruction, numerous and complex issues and problems remain for continued inquiry.  相似文献   

An evaluation of vocational education in Swedish upper secondary schools     

Rune Axelsson  Erik Wallin 《Studies in Educational Evaluation》1984,10(1):89-93

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Problem-based learning: An introduction   总被引：2，自引：0，他引：2  

Henk G. Schmidt 《Instructional Science》1994,22(4):247-250

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Cognitive Load Theory as a Tool for Expertise Development     

Rikers  Remy M.J.P.  Van Gerven  Pascal W.M.  Schmidt  Henk G. 《Instructional Science》2004,32(1-2):173-182

This special issue is dedicated to recentdevelopments within cognitive load theory (CLT)and identifies some instructional implicationsof the interaction between informationstructures and cognitive architecture. Thepresent article discusses the different studiesin this special issue. An important conclusionis that recent CLT research recognizes thelearners' level of expertise as an importantfactor mediating the relation between cognitivearchitecture, information structures, andlearning outcomes. In this context, we discussthe role of expertise in CLT research and therole of CLT in expertise research. Based onthis discussion, the use of CLT as a tool todevelop expertise is identified as a verypromising approach.  相似文献