Could knee joint mechanics during the golf swing be contributing to chronic knee injuries in professional golfers?     

Howie Carson  Jim Richards  Simon G. S. Coleman 《Journal of sports sciences》2020,38(13):1575-1584

ABSTRACT

Full three-dimensional movements and external moments in golfers’ knees and the possible involvement in injuries have not been evaluated using motion capture at high sample frequencies. This study measured joint angles and external moments around the three anatomical axes in both knees of 10 professional golfers performing golf drives whilst standing on two force plates in a motion capture laboratory. Significant differences were found in the knee joint moments between the lead and trail limbs for the peak values and throughout all stages during the swing phase. A significantly higher net abduction moment impulse was seen in the trail limb compared with the lead limb (?0.518 vs. ?0.135 Nms.kg^?1), indicating greater loading over the whole swing, which could contribute to knee lateral compartment or anterior cruciate ligament injuries. A significant correlation (r = ?0.85) between clubhead speed at ball contact and maximum joint moment was found, with the largest correlations being found for joint moments at the top of the backswing event and at the end of the follow-through. Therefore, although knee moments can contribute to high clubhead speeds, the large moments and impulses suggest that they may also contribute to chronic knee injuries or exacerbate existing conditions.  相似文献   

"武科应试器械"考论   总被引：1，自引：1，他引：0  

杨爱华  陈恳  李英  杨树  程远义 《军事体育进修学院学报》2006,25(3):42-46

从体育文化角度对古代“武科”考试内容、应试器械等进行系统研究。结果显示:“武科”,又称“武举”,创立于唐武则天长安二年(702年),废于清末光绪二十七年(1901年8月29日),历经一千二百年。考试分外场(以长垛、马射、步射、刀术、枪术、翘关等体育项目为主)和内场(策论)。唐“武科”主要外场器械为弓箭,辅从刀、枪等。宋以弓箭刀枪为主同时将弩踏等作为考试项目。明代“武科”项目沿袭唐宋,外场器械未有变化。清代开始增加了“技勇”项目,分别为开硬弓、舞大刀、掇石。课题研究旨在为我国民族传统体育学的长足发展提供实质性的理论文献资料。  相似文献   

The Community of Cinema: How Cinema and Spectacle Transformed the American Downtown     

Ken Dvorak 《Journal of American culture (Malden, Mass. : 2003)》2004,27(1):122-122

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Can constrained relevance feedback and display strategies help users retrieve items on mobile devices?     

Vishwa Vinay  Ingemar J. Cox  Natasa Milic-Frayling  Ken Wood 《Information Retrieval》2006,9(4):435-453

Searching online information resources using mobile devices is affected by small screens which can display only a fraction of ranked search results. In this paper we investigate whether the search effort can be reduced by means of a simple user feedback: for a screenful of search results the user is encouraged to indicate a single most relevant document. In our approach we exploit the fact that, for small display sizes and limited user actions, we can construct a user decision tree representing all possible outcomes of the user interaction with the system. Examining the trees we can compute an upper limit on relevance feedback performance. In this study we consider three standard feedback algorithms: Rocchio, Robertson/Sparck-Jones (RSJ) and a Bayesian algorithm. We evaluate them in conjunction with two strategies for presenting search results: a document ranking that attempts to maximize information gain from the user’s choices and the top-D ranked documents. Experimental results indicate that for RSJ feedback which involves an explicit feature selection policy, the greedy top-D display is more appropriate. For the other two algorithms, the exploratory display that maximizes information gain produces better results. We conducted a user study to compare the performance of the relevance feedback methods with real users and compare the results with the findings from the tree analysis. This comparison between the simulations and real user behaviour indicates that the Bayesian algorithm, coupled with the sampled display, is the most effective. Extended version of “Evaluating Relevance Feedback Algorithms for Searching on Small Displays, ” Vishwa Vinay, Ingemar J. Cox, Natasa Milic-Frayling, Ken Wood published in the proceedings of ECIR 2005, David E. Losada, Juan M. Fernández-Luna (Eds.), Springer 2005, ISBN 3-540-25295-9  相似文献   

The Pietist Vision of Christian Higher Education: Forming Whole and Holy Persons; and Reclaiming Pietism: Retrieving an Evangelical Tradition     

Ken Badley 《Christian Higher Education》2017,16(4):266-268

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flashGet使用教程     

Ken 《中小学电教》2003,(6):26-29

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A Peer‐tutoring Scheme to Support Independent Learning and Group Project Work in Mathematics     

Ken Houston 《Assessment & Evaluation in Higher Education》1996,21(3):251-266

A peer‐tutoring scheme was introduced to an undergraduate mathematics module. This was to provide a learning support for an independent learning programme. These student support groups also functioned as task groups for group project work. In the independent learning programme, students were directed to read selected passages of text, to attempt certain exercises and to devise peer assessment tasks. For some of the sessions senior students were present and functioned as additional peer tutors. To assess the students’ attitudes to the peer‐supported independent learning programme, an Attitudes to Peer‐tutoring Questionnaire was constructed. The results show that the students readily accepted the need to work in groups and to support one another. Overall, 78% felt that they could work easily without pressure and that the sessions were not a complete waste of time. However, 65% of the students did not appear to enjoy the independent learning sessions and felt that they preferred to be responsible only for their own learning.  相似文献   

Supervisor Development Programmes: Field Test One — the Feedback Role     

Ken Eltis 《Asia-Pacific Journal of Teacher Education》1984,12(1):19-30

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Orientation for distance education students: What is its worth?     

Don Bowser  Ken Race 《Distance Education》1991,12(1):109-122

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Organizational effectiveness in education: Its measurement and enhancement     

Peter Coleman 《Interchange》1972,3(1):42-52

This study is concerned with the nature of organizational goals, and ways of measuring goal achievement. It is intended to provide administrators with some new ways of conceptualizing the evalution of effectiveness in educational systems. The paper points out the desirability of involving professionals in the setting of goals, proposes a three-tier system of goals for educational systems, and suggests some of the reasons for the frequent failure to achieve organizational goals. Additionally, a comprehensive approach to the goals of organizations, adapted from Gross's matrix of purposes, is proposed, on the grounds that only such an inclusive approach to organizational goals is entirely satisfactory. Finally, the paper takes issue with the notion that freedom for organization members equals absence of organizational controls. The sense of power for organization members increases with participation in control, as does effectiveness. Thus, particularly for organizations with large numbers of professionals as members, it is not absence of control but rather participation in control that is the vital factor in both freedom and effectiveness. The final conclusion of the paper is that attempts to improve the effectiveness of educational systems or institutions must be in the future more inclusive, and that the matrix of purposes approach is one possible line of development.

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Résumé Cette étude porte sur la nature des objectifs des plans d'organisation et des méthodes servant à mesurer le degré de réussite dans la poursuite de ces objectifs. L'auteur se propose de fournir aux administrateurs un certain nombre de nouveaux critères pour concevoir l'évaluation de l'efficacité des systèmes éducatifs. Soulignant l'opportunité de confier à des professionnels l'établissement des objectifs, cette étude propose un système à trois paliers et tente d'expliquer les échecs fréquents auxquels aboutissent les objectifs des plans d'organisation. Par ailleurs, en ce qui concerne les objectifs des organisations, elle propose une attitude globale adaptée de l'étude de Gross intitulée matrix of purposes (matrice des objectifs), étant donné qu'une telle attitude est la seule qui soit satisfaisante à tous points de vue. Enfin l'auteur dénonce la notion selon laquelle la liberté accordée aux membres des organisations équivaut à une absence de contrôle sur ces dernières. En participant au contrôle de leurs organisations, les membres prennent en effet de plus en plus conscience de leur pouvoir et l'efficacité s'en trouve accrue. C'est ainsi que lorsqu'il s'agit, en particulier, d'organisations comptant de nombreux membres des professions libérales, ce n'est pas l'absence de contrôle mais plutôt la participation au contrôle qui représente le facteur capital à la fois de la liberté et de l'efficacité. En conclusion finale, cette étude affirme qu'à l'avenir, les tentatives d'amélioration des systèmes éducatifs ou des institutions devront avoir un caractère plus global et que la matrice des objectifs représente l'une des méthodes possibles à adopter dans ce domaine.

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