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Aaron J. Beach René E. D. Ferdinands Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):295-313
Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling. 相似文献
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The nature and correlates of underachievement among elementary schoolchildren in Hong Kong 总被引：2，自引：0，他引：2
This study investigated for the first time several characteristics of underachievement in a large sample of Hong Kong elementary schoolchildren. More males were identified as underachievers than females, but the ratio was substantially less than the two-to-one rate typically found in the American literature. The stability and persistence of underachievement increased during the elementary school years, and the stability of underachievement tended to be higher in subject matter that was relatively more difficult, which varied with gender. Underachievement became more specific to particular academic subjects rather than more general across the elementary grades. Parents and teachers, but not the children themselves, perceived that underachievers were more capable than same-grade nonunderachievers (who score lower on ability tests), although this awareness is more likely directed at male than female underachievers, which has been observed in other samples. In grades 1-4, teachers provided extra mentoring, communications, and support to underachievers. Thereafter, underachievers became more disruptive, impatient, and aggressive in school and perhaps at home. At that point, teachers became less supportive, offered less extra mentoring, and applied greater behavioral control over underachievers. Underachieving children also perceived that their parents became less supportive and used more discipline in grades 5-6 relative to grades 3-4. These correlates of underachievement suggests the existence of a syndrome of underachievement that separates underachievers from children who have the same grades but lower mental ability. 相似文献
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Positive values for fairness in competition are supposed to undergird the behavior of athletes engaged in sport. Whether athletes' values actually develop over 4 years in a college that emphasizes character development is the focus of this study. Athletes' (N = 631) use of deontological ethics (Hahm, Beller & Stoll, 1989) in 21 sports value dilemmas were evaluated. At entrance, as well as near graduation, intercollegiate athletes' value scores were lower than intramural athletes' scores. Both groups' scores declined while they were in college. Individual-sport athletes had higher scores than team-sport athletes but manifested a greater decline over 4 years. The findings are consistent with other studies that show decreases in "sportsmanship orientation" and an increase in "professional" attitudes associated with participation in sport. 相似文献
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In this article, using data from ethnographic research, we try to present some glimpses of the way education is described as an experience and possibility ‘from below’, by pupils who grow up and study in schools in the most segregated and territorially stigmatized suburbs on the outskirts of our major cities. What we feel they describe is an experience of schooling for surviving the social and economic consequences of curtailed citizenship in a post‐industrial society rather than one of schooling that offers possibilities of integration and full citizenship or social transformation. Our findings have significant policy implications in this respect. Sweden has historically pursued projects aimed at educational inclusion but has recently taken a significant turn toward neo‐liberalism and educational consumerism, since which time various disadvantaged groups have become increasingly concentrated compared with others in under‐achieving schools in an economically threatened public sector. The article discusses some aspects and possible consequences of this development. 相似文献
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Measure of opportunity: assessing equitable conditions to learn twenty-first century thinking skills
Learning Environments Research - Many school change efforts aim to foster conditions for the development of students’ twenty-first century skills in an equitable and comprehensive way, but... 相似文献
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This paper analyses recent educational reforms on teachers’ work in Sweden following the 2010 Education Act, and up to the School Commission Report released in April 2017. We draw upon key policy texts and associated documents from the Ministry of Education, and the Swedish National Agency for Education (Skolverket). We consider the background to the reforms, their relations with one another and how they have played out in the Swedish educational policy context. We argue that these reforms exhibit features of ‘fast policy’ in terms of how they have taken on an increasingly centralised and neoliberal character, and the rapid-fire way they have been directed at teachers as individuals, rather than broader schooling structures. We show how the fast policy reforms have recentralised schooling and teachers’ work—effectively de-professionalising educators. 相似文献
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This article will argue that five different ways of doing phenomenography can be found amongst the works of Gothenburg phenomenographers: Discursive, Experimental, Naturalistic, Hermeneutic and Phenomenological. Commenting on an earlier version of phenomenography, Jacob Needleman stated that it was “a ‘good‐for‐nothing’ brother of phenomenology”. We will argue that it is not. It is productive research, even if at times the degree of methodological reflection applied by phenomenographers to their work is found wanting. Two of five forms of Gothenburg phenomenography can be developed by recourse to phenomenology. 相似文献
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Aaron J. Beach René E. D. Ferdinands Peter J. Sinclair 《Journal of sports sciences》2018,36(10):1127-1134
The techniques of spin bowling in cricket have been largely formulated from the collective intuitions of past players. A standard model of bowling technique has been generally prescribed for both off-spin and leg-spin bowlers, but there has been no biomechanics research to validate this approach. This study measured 20 Type-2 off-spin and 15 Type-2 leg-spin bowlers using a 3D Cortex motion analysis system. Correlation coefficients between segmental kinematic variables and spin rate in the off-spin and leg-spin bowlers revealed that off-spin bowling was associated with an earlier movement time of the thorax, whereas leg-spin bowling was associated with a greater magnitude and earlier movement time of pelvis rotation, as well as a greater magnitude of pelvis-shoulder separation movement. The maximum velocity of rear hip flexion differentiated between both groups of bowlers. The GLM suggested that for off-spinners, rear hip flexion velocity significantly explained the variance in spin rate (subject to sequential timing constraints), while for leg-spinners, the time of maximum rear hip flexion and maximum arm circumduction velocity significantly explained variance in spin rate. This study supports the notion that off-spinners and leg-spinners have significant differences in their joint kinematics, and should not be coached under a one-size-fits-all technical model. 相似文献