Effects of golf shaft stiffness on strain, clubhead presentation and wrist kinematics     

Betzler NF  Monk SA  Wallace ES  Otto SR 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(2):223-238

The aim of this study was to quantify and explain the effect of shaft stiffness on the dynamics of golf drives. Twenty golfers performed swings with two clubs designed to differ only in shaft bending stiffness. Wrist kinematics and clubhead presentation to the ball were determined using optical motion capture systems in conjunction with a radar device for capturing ball speed, launch angle, and spin. Shaft stiffness had a marginally small effect on clubhead and ball speeds, which increased by 0.45% (p < 0.001) and 0.7% (p = 0.008), respectively, for the less stiff club. Two factors directly contributed to these increases: (i) a faster recovery of the lower flex shaft from lag to lead bending just before impact (p < 0.001); and (ii) an increase of 0.4% in angular velocity of the grip of the lower flex club at impact (p = 0.003). Unsurprisingly, decreases in shaft stiffness led to more shaft bending at the transition from backswing to downswing (p < 0.001). Contrary to previous research, lead bending at impact marginally increased for the stiffer shaft (p = 0.003). Overall, and taking effect sizes into account, the changes in shaft stiffness in isolation did not have a meaningful effect on the measured parameters, for the type of shaft investigated.  相似文献   

Literacy in the digital age: Learning from computer games     

Catherine Beavis  Thomas Apperley  Clare Bradford  Joanne O'Mara  Christopher Walsh 《English in Education》2009,43(2):162-175

The need for literacy and the English curriculum to attend to digital literacies in the twenty-first century is well established. Although studies in digital literacies have examined the inclusion of computer games in schools, there has not been an extended study of English teachers incorporating computer games into their teaching and learning through action research projects. This paper outlines the structure and progress of a research project exploring the uses of computer games in English classrooms. We argue that much can be learned about the teaching of both print and digital literacies from examining computer games and young people's engagement in online digital culture in the world beyond school.  相似文献   

Moving distance education research forward     

Wallace Hannum 《Distance Education》2009,30(1):171-173

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Guest editorial: Preconceptions and theoretical frameworks     

John Wallace  William Louden 《科学教学研究杂志》1997,34(4):319-322

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Multi-joint rate of force development testing protocol affects reliability and the smallest detectible difference     

David Drake  Rodney A. Kennedy  Eric S. Wallace 《Journal of sports sciences》2019,37(14):1570-1581

Isometric tests have been used to assess rate of force development (RFD), however variation in testing methodologies are known to affect performance outcomes. The aim of this study was to assess the RFD in the isometric squat (ISqT) using two test protocols and two testing angles. Eleven participants (age: 26.8 ± 4.5 years, strength training experience: 7.1 ± 3.03 years) completed test and retest sessions one week apart, whereby two test protocols with respect to duration and instructions were compared. Isometric peak force (ISqT^peak) and isometric explosive force (ISqT^exp) tests were assessed at two joint angles (knee flexion angle 100° and 125°). Force-time traces were sampled and subsequently analysed for RFD measures. Average and instantaneous RFD variables did not meet reliability minimum criteria in ISqT^peak at 100° or 125°. The ISqT^exp test at 100° met reliability criteria in the RFD 0–200 and 0–250ms variables. The ISqT^exp test at 125° met reliability criteria in the RFD 0–150, 0–200 and 0–250ms variables. Force-time characteristics were optimized at the higher knee joint angle. Average and instantaneous RFD measures obtained using a traditional peak force test do not meet basic reliability criteria. Researchers assessing multi-joint RFD should employ the explosive RFD test protocol as opposed to the traditional isometric peak force protocol.  相似文献   

Analyzing “affective” goal statements     

John A. Stuart  Squy G. Wallace 《Performance Improvement》1988,27(10):10-14

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Influence of shaft length on golf driving performance     

Kenny IC  Wallace ES  Otto SR 《Sports biomechanics / International Society of Biomechanics in Sports》2008,7(3):322-332

The aim of this study was to determine how shaft length affects golf driving performance. A range of drivers with lengths between 1.168 m and 1.270 m, representing lengths close to the 1.219 m limit imposed by R&A Rules Limited (2008), were assembled and evaluated. Clubhead and ball launch conditions and drive distance and accuracy were determined for seven category 1 golfers (handicaps 0.21 +/- 2.41) who performed shots on a purpose-built practice hole. As shaft length increased from 1.168 m to 1.270 m, initial ball velocity increased (+ 1.8 m/s, P < 0.01). Ball carry (+ 4.3 m, P = 0.152) also increased, although not significantly so. Furthermore, as shaft length increased, for all club comparisons there was no decrease in accuracy. Ball launch conditions of spin components and launch angle remained unaffected by shaft length. Launch angle increased (0.8 degree, F = 1.074, P = 0.362) as driver shaft length increased. Our results show that clubhead and ball velocity together with ball carry tended to increase with no loss of accuracy.  相似文献   

The titration of silver with potassium iodide. Use of four selected oxidizing agents and starch as indicators     

Jay H. Quinn  Wallace M. McNabb 《Journal of The Franklin Institute》1945,240(1):47-52

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Entrepreneurial Academics: Developing Scientific Careers in Changing University Settings     

Joanne Duberley  Laurie Cohen  Elspeth Leeson 《Higher Education Quarterly》2007,61(4):479-497

This paper examines the impact of entrepreneurial initiatives within universities on scientific careers. Based on the career accounts of university‐based bioscientists involved in a government‐sponsored entrepreneurship training initiative, the paper explores the concept of academic entrepreneurialism. Three groups were identified in the data. First, academic entrepreneurs, who tended to be more experienced scientists and were now able to capitalise on their science. Second, those interested in technology transfer, who saw their career path taking them away from science, and finally a group of younger scientists who were trying to develop their career capital but were unsure what direction their career would take. The implications of these different groups for the management of universities and the development of knowledge are considered.  相似文献   

Looking back, looking forward: Re-searching the conditions for curriculum integration in the middle years of schooling     

John Wallace  Rachel Sheffield  Leonie Rénnie  Grady Venville 《The Australian Educational Researcher》2007,34(2):29-49

In Australia, and internationally, integration is a widely promoted middle school curriculum reform strategy. Integration is claimed to engage students by providing opportunities to work on a few cross-disciplinary objectives, to apply knowledge across the subject boundaries and to work on tasks with meaning and relevance. While these curriculum goals enjoy a certain popularity among middle school reformers and curriculum integration adherents, in practice, the prevalence of integration is patchy and provisional. In this article, we (re) examine two of our studies of middle school integration over the past decade to explore the reasons for this apparent disparity between the rhetoric and the reality. In our re-search for integration, we look back at our data to identify enabling and inhibiting conditions for curriculum reform and develop a list of key program characteristics. Finally, we look forward, drawing on the notion of institutional resilience to speculate on the reasons why some middle school programs seem to flourish while others wither.  相似文献