Coordination variability and skill development in expert triple jumpers   总被引：1，自引：0，他引：1  

Wilson C  Simpson SE  van Emmerik RE  Hamill J 《Sports biomechanics / International Society of Biomechanics in Sports》2008,7(1):2-9

The aim of this study was to examine the influence of skill of expert triple jumpers on the coordination variability of lower extremity intra-limb couplings. In contrast to the traditional motor learning perspective, we hypothesized that as skill and thus performance increases, movement coordination variability will also increase. Three-dimensional kinematic and ground reaction force data were collected during the hop-step transition phase of the triple jump. Relative motion plots and a modified vector coding technique were used to quantify the coordination variability across the trials. The results were consistent with a U-shaped curve, representing coordination variability, as skill increases. The high coordination variability in less skilled athletes is present while the appropriate characteristics defining the movement coordination patterns are acquired. This coordination variability may not be beneficial to performance. As the refinement of these characteristics is achieved, coordination variability decreases, resulting in a more consistent or regulated performance. In the final stages of developing a skilled performance, a functional variability is accessed that brings flexibility to the system allowing it to cope with perturbations. This study highlights the need to address the learning effect when analysing coordination variability from a dynamical systems perspective.  相似文献   

The metallurgy and assaying of the precious metals used in coinage     

Alexander E. Outerbridge 《Journal of The Franklin Institute》1877,103(4):281-290

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Do physical activity beliefs differ by age and gender?   总被引：1，自引：0，他引：1  

Rhodes RE  Blanchard CM  Blacklock RE 《运动与训练心理学杂志》2008,30(3):412-423

Age and gender are consistently related to physical activity (PA), yet theoretical explanation for these associations is scant. The present study compared the mean values and correlations of a population sample, divided by gender and age group, with respect to theory of planned behavior beliefs (behavioral, normative, and control) and PA. Participants were a sample (N=6,739) of adults (M age=49.65, SD=16.04) who completed measures of social and health demographics, theory of planned behavior beliefs, and self-reported PA. Mean analyses identified greater perceived control over PA for seniors than for young and middle-aged adults (N>.025). Belief-behavior correlations, however, were not different across age and gender in 24 of 26 tests (q<.19). Thus, PA beliefs are invariant across age and gender with the exception of mean levels of perceived control, which are lower among younger adults than older adults. Factors such as early parenthood and career demands were considered the likely reasons for differences. Overall, the evidence suggests that adapting theoretical models for specific age groups or based on gender may not be necessary.  相似文献   

“Hypnotizzy” in the Cold War: The American Fascination with Hypnotism in the 1950s     

Robert Genter 《Journal of American culture (Malden, Mass. : 2003)》2006,29(2):154-169

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Time and implementing change     

Barry E. Porter  Sr. 《British journal of educational technology : journal of the Council for Educational Technology》2005,36(6):1063-1065

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The effective path length through a vertical cosmic-ray telescope     

Enós E. Witmer  Martin A. Pomerantz 《Journal of The Franklin Institute》1948,246(4):293-309

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Report of The Committee on a Coordinated Abstracting Service for Clinical Medicine and a Summary of Two Conferences on Scientific Abstracting Held in Paris,in April, 1948, at UNESCO House     

Fair E  Cunningham ER 《Bulletin of the Medical Library Association》1948,36(4):379-408

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对我国运动员进行心理表象训练新程序的理论探讨   总被引：2，自引：0，他引：2  

高守清 《四川体育科学》2002,(4):9-10,15

表象训练是体育运动实践中运用最广泛的训练方法之一。我国在此领域远远落后于日本，其主要因素包括表象训练的方法、个体差异和情境因素：日本新近开发的心理表象训练程序(简称MITP)，几经实践运用，不仅训练效果良好而且在运动训练和比赛心理的理论方面产生了积极的影响，检验了有关表象训练的理论问题，认为动觉表象、视觉表象和想象表象有机结合是提高心理训练效果的良好途径；对MITP作一些理论探讨，目的在于为我国体育运动心理学理论建设提供一点参考。  相似文献   

Library-Bibliographical Classification (LBC): General characteristics and basic functions and prospects for development     

E. R. Sukiasyan 《Scientific and Technical Information Processing》2008,35(1):55-61

This paper considers the background of the Library-Bibliographic Classification as the national classification system of Russia, and its history and application in the USSR. It gives the general characteristic of the LBC structure, content and system of designations, as well as the state of its present updating.  相似文献   

Condensed financial report as at August 31, 1939     

W.F.G. Swann  W.E. Ramsey 《Journal of The Franklin Institute》1940,229(5):661-663

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