An evaluation of biomechanical measures of bowling action legality in cricket     

René E.D. Ferdinands  Uwe G. Kersting 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):315-333

Cricket bowling is traditionally thought to be a rigid-arm motion, allowing no elbow straightening during the delivery phase. Conversely, research has shown that a perfectly rigid arm through delivery is practically unattainable, which has led to rule changes over the past years. The current rule requires a bowler not to increase the elbow angle by more than 15°, thus requiring a measurement to confirm legality in “suspect” bowlers. The aims of this study were to evaluate whether the current rule is maintained over a range of bowlers and bowling styles, and to ascertain whether other kinematics measures may better differentiate between legal and suspect bowling actions. Eighty-three bowlers of varying pace were analysed using reflective markers and a high-speed (240 Hz) eight-camera motion analysis system in a laboratory. The change in elbow segment angle (minimum angle between the arm and forearm), the change in elbow extension angle with respect to the flexion–extension axis of a joint coordinate system, and the elbow extension angular velocity at ball release were measured. We found that bowlers generally bowled within a change in elbow extension angle of 15°. However, this limit was unable to differentiate groups of bowlers from those who were suspected of throwing in the past. Improved differentiation was attained using the elbow extension angular velocity at ball release. The elbow extension angular velocity at ball release may be conceptually more valid than the elbow extension angle in determining which bowlers use the velocity-contributing mechanisms of a throw. Also, a high value of elbow extension angular velocity at ball release may be related to the visual impression of throwing. Therefore, it is recommended that researchers and cricket legislators examine the feasibility of specifying a limit to the elbow extension angular velocity at ball release to determine bowling legality.  相似文献   

Centre of mass kinematics of fast bowling in cricket     

Rene Ferdinands  Robert N. Marshall  Uwe Kersting 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):139-152

Kinematic studies have shown that fast bowlers have run-up velocities, based on centre of mass velocity calculations, which are comparable to elite javelin throwers. In this study, 34 fast bowlers (22.3 ± 3.7 years) of premier grade level and above were tested using a three-dimensional (3-D) motion analysis system (240 Hz). Bowlers were divided into four speed groups: slow-medium, medium, medium-fast, and fast. The mean centre of mass velocity at back foot contact (run-up speed) was 5.3 ± 0.6 m/s. Centre of mass velocity at back foot contact was significantly faster in the fastest two bowling groups compared to the slow-medium bowling group. In addition, stepwise multiple regression analysis showed that the centre of mass deceleration over the delivery stride phase was the strongest predictor of ball speed in the faster bowling groups. In conclusion, centre of mass kinematics are an important determinant of ball speed generation in fast bowlers. In particular, bowlers able to coordinate their bowling action with periods of centre of mass deceleration may be more likely to generate high ball speed.  相似文献   

Teaching and learning under COVID-19 public health edicts: the role of household lockdowns and prior technology usage     

Guppy  Neil  Boud  David  Heap  Tania  Verpoorten  Dominique  Matzat  Uwe  Tai  Joanna  Lutze-Mann  Louise  Roth  Mary  Polly  Patsie  Burgess  Jamie-Lee  Agapito  Jenilyn  Bartolic  Silvia 《Higher Education》2022,84(3):487-504

Higher Education - Public health edicts necessitated by COVID-19 prompted a rapid pivot to remote online teaching and learning. Two major consequences followed: households became students’...  相似文献   

Teaching Stress Management in Physical Education: A Quasi-Experimental Study with Vocational Students     

Christin Lang  Serge Brand  Flora Colledge  Edith Holsboer-Trachsler  Uwe Pühse  Markus Gerber 《Scandinavian Journal of Educational Research》2019,63(2):245-257

The aim was to develop, implement, and evaluate a physical education-based coping training program for vocational students. Two vocational schools participated in the quasi-experimental pilot study (EPHECT I). One school received the intervention (intervention group: n?=?434), while the other school maintained regular physical education classes (control group: n?=?430). Repeated measures ANCOVAs were used to examine the effects on coping and perceived stress. Additionally, effects were compared among students who reported low versus elevated life satisfaction. Finally, the implementation rate was considered as a moderating factor. Overall, no significant time by group effects were found between the intervention group and the control group. However, a reduction in maladaptive coping occurred among students of the intervention group who reported low life satisfaction. The implementation rate did not moderate the findings. Despite a relatively low implementation rate, the intervention program reduced maladaptive coping strategies in adolescents with low life satisfaction. Program monitoring needs to be increased in future research.  相似文献   

Understanding Social Processes of Innovation Development     

Uwe Hameyer 《课程研究杂志》2013,45(4):362-366

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Distance learners of German and intercultural competence     

Uwe Baumann  Monica Shelley 《Open Learning》2013,28(3):191-204

The article describes a research project undertaken with advanced adult learners of German at a distance at The Open University, United Kingdom. Their gains in intercultural competence were investigated by looking at how far the students met the prescribed learning outcomes, their knowledge items, language skills, attitudes towards Germans and their assessment results. The findings show that this particular group of learners felt that they had achieved the different requirements of the stated learning outcomes to a surprisingly high level and demonstrated a high level of intercultural competence. In addition, these learners were able to articulate their opinions of commonly held attitudes and stereotypical views about Germans and offered reflective insights into why their personal attitudes differed in many respects from more commonly held views.  相似文献   

Effects of Aerobic Exercise on Cognitive Performance Among Young Adults in a Higher Education Setting     

Sebastian Ludyga  Markus Gerber  Serge Brand  Uwe Pühse  Flora Colledge 《Research quarterly for exercise and sport》2018,89(2):164-172

Purpose: Acute benefits of aerobic exercise on executive functioning have been reported frequently under laboratory conditions. However, to date, a beneficial effect on long-term memory has been less well supported and no data are available regarding nonlaboratory conditions in young adults. The aim of the current study was to investigate acute effects of aerobic exercise on cognitive functioning in a university classroom setting. Method: Using a cross-over design, 51 participants performed a bout of moderately intense running (RUN) and read an article while seated (CON). Afterwards, they completed free-recall tests, followed by a Flanker task and an n-back task. Results: Participants in the RUN condition compared with those in the CON condition showed shorter reaction time on the inhibition task, F(1, 50) = 5.59, p = .022, η² = .101, and recalled more words in the immediate- and delayed-recall tests, F(1, 50) = 8.40, p = .006, η² = .144. Conclusion: The present findings suggest that a moderately intense bout of aerobic exercise benefits verbal short-term and long-term memory as well as inhibitory control among students in a classroom setting.  相似文献   

Doping im Hochleistungssport: Anpassung durch Abweichung     

Karl-Heinrich Bette  Uwe Schimank  R. Stichweh 《Sportwissenschaft》1996,26(2):216-220

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Educational career and substance use in adolescence     

Uwe Engel  Elisabeth Nordlohne  Klaus Hurrelmann  Birgit Holler 《European Journal of Psychology of Education - EJPE》1987,2(4):365-374

In modern, competitive societies the social organisation of «youth» implies both the chance and risk of (intergenerational) vertical social mobility. It is suggested that it is precisely this basic feature that to a considerable extent gives rise to substance use. In particular the paper aims at analysing the impact of the risk of educational downward mobility as well as some related characteristics. Using LISREL VI, it is shown that this type of educational career pattern, actual or anticipated, substantially contributes to the consumption of legal drugs. Weight is given to an extended analysis of the mode of action involved in the relationship between substance use and the career pattern as well as associated characteristics, respectively. As far as home is concerned, social conflict and associated feelings on the side of the adolescents turn out to be a major ‘mechanism’ through which the observable impact of educational downward mobility can be traced back. Integration into both the cultural system of «legalized» drug use and subcultural contexts as provided by social cliques is a further condition that strongly influences substance use among adolescents.  相似文献   

Grundbildung,Allgemeinbildung und Fachunterricht     

Uwe?HericksEmail author 《Zeitschrift für Erziehungswissenschaft》2004,7(2):192-206

Zusammenfassung Der Beitrag thematisiert das nicht unproblematische Spannungsverh?ltnis von Grundbildung, Allgemeinbildung und Fachunterricht. Anspruchsvolle Fachinhalte, die über die in der internationalen PISA-Studie untersuchten Basiskompetenzen hinausgehen, lassen sich nicht mit einem normativen Verweis auf allgemeine Kompetenzen (wie Lernf?higkeit, Sozial-oder Probleml?sekompetenz) für alle Heranwachsenden rechtfertigen. Die Allgemeinheit der Bildung ist vielmehr im Faktum der Kontingenz und Differenz jeglicher Fachinhalte zu suchen. Bildung wird dabei als die F?higkeit zum Umgang mit Ungewissheit definiert. Anhand einer Fallstudie mit einer Hamburger Lehrerin wird gezeigt, dass diese Bestimmung für Lehrende pragmatisch auf die Realisation „guten“ Fachunterrichts hinauslaufen kann. Unter Bildungsaspekten zeigt sich das Handeln der Lehrerin dabei implizit an einer Als-ob-Didaktik orientiert, deren Grundzüge im Beitrag verallgemeinernd herausgearbeitet werden. Eine geeignete Rahmenkonzeption dafür steht mit der Bildungsgangdidaktik zur Verfügung, die die tats?chlichen Lern-und Bildungsprozesse der Schülerinnen und Schüler in das Zentrum ihrer Theoriebildung stellt.

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Summary Basic education, general education and subject-focused lessons This contribution focuses on the not unproblematic tensions between basic education, general education and subject-focused lessons. Demanding subject matter, which offers more than those basic competencies studied in the international PISA study, cannot be justified for all learners with a normative reference to the attainment of general competencies (i.e. learning, social and problem-solving skills). Generality is indeed to be found in the contingency and difference of subject matter. Bildung is defined as the ability to deal with uncertainty. On the basis of a case study of a teacher from Hamburg, it will be demonstrated that this concept can — in pragmatic terms — simply mean the realization of „good“ subject-focused teaching. According to the theory of Bildung, it can be shown that the teache’s work is implicitly based on a didactic with as-if-character, which will be further generalized in this paper. An appropriate framework for such concepts is offered by the Bildungsgangdidaktik, which places the realized learning and educational processes at the center of its theory.

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