Effect of gear ratio on peak power and time to peak power in BMX cyclists     

Lee P. Rylands  Simon J. Roberts  Howard T. Hurst 《European Journal of Sport Science》2017,17(2):127-131

The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders’ bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14)?=?6.448; p?=?.010) and peak torque (F(2,14)?=?4.777; p?=?.026), but no significant difference was found for time to peak power (F(2,14)?=?0.200; p?=?.821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658?±?221?W, compared to 1436?±?129?W and 1380?±?56?W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in ?0.01?s and a 45/16 in 0.22?s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.  相似文献   

An occlusion paradigm to assess the importance of the timing of the quiet eye fixation     

Samuel J. Vine  Don Hyung Lee  Rosanna Walters-Symons  Mark R. Wilson 《European Journal of Sport Science》2017,17(1):85-92

Abstract

The aim of the study was to explore the significance of the ‘timing’ of the quiet eye (QE), and the relative importance of late (online control) or early (pre-programming) visual information for accuracy. Twenty-seven skilled golfers completed a putting task using an occlusion paradigm with three conditions: early (prior to backswing), late (during putter stroke), and no (control) occlusion of vision. Performance, QE, and kinematic variables relating to the swing were measured. Results revealed that providing only early visual information (occluding late visual information) had a significant detrimental effect on performance and kinematic measures, compared to the control condition (no occlusion), despite QE durations being maintained. Conversely, providing only late visual information (occluding early visual information) was not significantly detrimental to performance or kinematics, with results similar to those in the control condition. These findings imply that the visual information extracted during movement execution – the late proportion of the QE – is critical when golf putting. The results challenge the predominant view that the QE serves only a pre-programming function. We propose that the different proportions of the QE (before and during movement) may serve different functions in supporting accuracy in golf putting.  相似文献   

Chronicling the West for “Harper's”: Coast to Coast with Frenzeny & Tavernier in 1873–1874 Claudine Chalmers. Norman: University of Oklahoma Press, 2013.          下载免费PDF全文

Cynthia Lee Patterson 《Journal of American culture (Malden, Mass. : 2003)》2015,38(2):156-157

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Interrogating Identity and Social Contexts Through “Critical Family History”     

John Lee  Christine Sleeter  Kevin Kumashiro 《Multicultural Perspectives》2015,17(1):28-32

Tracing one's family genealogy is a complex process that requires situating a family's narratives within a historical context. This article reviews the use of critical family history research in an undergraduate Asian American studies course to examine not only the diversity and experiences of Asian Americans but also the unspoken narratives that lead to the creation of a single story. We are told single stories that often neglect the sociocultural factors—the historical reality—of our past. Our family histories are constructed historically and are embedded in social, political, and economic processes and relationships. This article argues that we need to complicate what we know about our past and examine policies and cultural practices that lead to a racialized system of power and privilege, racialized policies, and racialized oppression and progression.  相似文献   

(Re) Claiming Native Youth Knowledge: Engaging in Socio-culturally Responsive Teaching and Relationships     

Tiffany S. Lee  Patricia D. Quijada Cerecer 《Multicultural Perspectives》2013,15(4):199-205

This article reveals Native youth perspectives on socio-culturally responsive education. The authors draw on two studies conducted in the Southwest among Navajo and Pueblo students. Youth convey the importance of meaningful, reciprocal, and transformative learning experiences and relationships at school. The article ends with suggestions for creating a socio-culturally responsive school environment.  相似文献   

Mapping cultural assets and evaluating significance: theory,methodology and practice     

David Lee  Abigail Gilmore 《Cultural Trends》2012,21(1):3-28

Over the last decade in the UK, there has been a notable shift in the popularity and use of cultural mapping as a methodology for policy making at a regional and local level. This follows increased demand for an informed framework for planning arts and cultural facilities from local and regional government and from within the cultural sector (Evans, 2008: p. 65). The article begins with an exploration of cultural mapping within cultural policy, which explores the context for the growth in this area of activity, and why this kind of activity appeals to policy makers and organisations. It then goes on to examine four cultural mapping exercises which have been undertaken in recent years in the UK. These studies have been chosen because although they all focus the mapping of cultural assets within a specific geographic area, they differ to one degree or another in purpose, context, definition, geographic scale and methodology. They illustrate the narrow range of approaches deployed in the cultural mapping field in the UK, and as such provide a useful means of critically reviewing their limits as well as highlighting the issues and challenges faced by cultural cartography in practice. The article concludes by considering the type of mapping research that is “allowed” within the discursive confines of consultancy based cultural policy research.  相似文献   

Bringing Pierre Bourdieu to Science and Technology Studies     

Mathieu?AlbertEmail author  Daniel?Lee?Kleinman 《Minerva》2011,49(3):263-273

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Regional creative industries policy-making under New Labour     

David Lee  David Hesmondhalgh  Kate Oakley  Melissa Nisbett 《Cultural Trends》2014,23(4):217-231

This article analyses creative industries policy in the English regions under New Labour (1997–2010). It examines the ideas behind regional creative industries policies (RCIPs) and their implementation. Focusing on the activities of the English regional development agencies, the primary bodies responsible for the implementation of creative industries policy in the British regions, the article places regional cultural policy during the New Labour period within its broader political, social and economic contexts. It explains and evaluates New Labour's RCIPs, arguing that creative industries policy at the regional level changed over the course of New Labour's three terms of office, becoming increasingly economistic at the expense of a more social democratic vision of regional equality and democracy. We identify three issues that were problematic for New Labour's RCIP: a reliance on the idea of “clusters”, commercialisation and shifting regional governance.  相似文献   

Multiple regression data using the WISC-R and the Woodcock-Johnson tests of cognitive ability     

Leadelle Phelps  Martin Rosso  Sharon Lee Falasco 《Psychology in the schools》1985,22(1):46-49

Using a sample of 100 behavior disordered male adolescents, correlations between the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Woodcock-Johnson Tests of Cognitive Abilities (WJTCA) were computed. All WISC-R subtests correlated with the W-J Broad Cognitive Ability score at the .0001 level. Analysis of the forward selection multiple regression procedure resulted in the inclusion of only WISC-R Verbal subtests for the first six steps. Implications of such results were discussed and a predictive equation reported.  相似文献   

Research Trends in Science Education from 2003 to 2007: A content analysis of publications in selected journals     

Min‐Hsien Lee  Ying‐Tien Wu 《International Journal of Science Education》2013,35(15):1999-2020

The present study was a follow‐up to Tsai and Wen’s (2005) earlier research, in which 802 articles published in the International Journal of Science Education, Science Education, and the Journal of Research in Science Teaching from 1998 to 2002 were analysed in terms of author’s nationality, research type, and research topic. In the present study a total of 869 papers published in the three journals from 2003 to 2007 were analysed, and the results were compared with those of Tsai and Wen. Moreover, this study also identified 31 highly‐cited papers published during 1998–2002 and 20 highly‐cited papers published during 2003–2007. The results showed that authors from countries other than the four major English‐speaking countries (i.e., the USA, the UK, Australia, and Canada) published an increasing number of articles in the past decade. During these five years (2003–2007), science educators showed relatively more interest in research topics involving the context of student learning. Besides, science educators have changed some of their research interests during 1998–2007, with a shift in the research topics from student conception learning and conceptual change (1998–2002) to student learning contexts (2003–2007). Moreover, the investigation of highly‐cited papers in the past decade revealed that studies on argumentation have gained significant attention among science educators.  相似文献