A kinematic analysis of the spine during rugby scrummaging on natural and synthetic turfs     

Ramesh Swaminathan  Jonathan M. Williams  Michael D. Jones 《Journal of sports sciences》2016,34(11):1058-1066

Artificial surfaces are now an established alternative to grass (natural) surfaces in rugby union. Little is known, however, about their potential to reduce injury. This study characterises the spinal kinematics of rugby union hookers during scrummaging on third-generation synthetic (3G) and natural pitches. The spine was sectioned into five segments, with inertial sensors providing three-dimensional kinematic data sampled at 40 Hz/sensor. Twenty-two adult, male community club and university-level hookers were recruited. An equal number were analysed whilst scrummaging on natural or synthetic turf. Players scrummaging on synthetic turf demonstrated less angular velocity in the lower thoracic spine for right and left lateral bending and right rotation. The general reduction in the range of motion and velocities, extrapolated over a prolonged playing career, may mean that the synthetic turf could result in fewer degenerative injuries. It should be noted, however, that this conclusion considers only the scrummaging scenario.  相似文献   

Perceptual training effects on anticipation of direct and deceptive 7-m throws in handball     

Khaled E. Alsharji  Michael G. Wade 《Journal of sports sciences》2016,34(2):155-162

We examined the effectiveness of perceptual training on the performance of handball goalkeepers when anticipating the direction of both direct and deceptive 7-m throws. Skilled goalkeepers were assigned equally to three matched-ability groups based on their pre-test performance: a perceptual training group (n = 14) received video-based perceptual training, a placebo training group (n = 14) received video-based regular training and a control group received no training. Participants in the perceptual training group significantly improved their performance compared to both placebo and control groups; however, anticipation of deceptive throws improved less than for direct throws. The results confirm that although anticipating deception in handball is a challenging task for goalkeepers, task-specific perceptual training can minimise its effect and improve performance.  相似文献   

A coach’s political use of video-based feedback: a case study in elite-level academy soccer     

Michael Booroff  Lee Nelson  Paul Potrac 《Journal of sports sciences》2016,34(2):116-124

This paper examines the video-based pedagogical practices of Terry (pseudonym), a head coach of a professional junior academy squad. Data were collected through 6 in-depth, semi-structured interviews and 10 field observations of Terry’s video-based coaching in situ. Three embracing categories were generated from the data. These demonstrated that Terry’s video-based coaching was far from apolitical. Rather, Terry strategically used performance analysis technologies to help fulfil various objectives and outcomes that he understood to be expected of him within the club environment. Kelchtermans’ micropolitical perspective, Callero’s work addressing role and Groom et al.’s grounded theory were primarily utilised to make sense of Terry’s perceptions and actions. The findings point to the value of developing contextually grounded understandings of coaches’ uses of video-based performance analysis technology. Doing so could better prepare coaches for this aspect of their coaching practice.  相似文献   

A topography of free kicks in soccer     

Daniel Link  Otto Kolbinger  Hendrik Weber  Michael Stöckl 《Journal of sports sciences》2016,34(24):2312-2320

ABSTRACT

This study investigates the spatial relationship of performance variables for soccer free kicks. In order to suggest ways in which players might optimise their performance, we collected data from free kicks (<35 m to goal line) of two German Bundesliga seasons (2013/14, 2014/15) (n = 1624). In the analysis, we applied the ISO-map approach using colour gradients to visualise the mean values of a variable on a 2D-map of the pitch. Additionally, variograms were used to describe the degree of spatial dependence of the free kick variables. Results show that DENSITY, TYPE OF PLAY, PLAYERS IN WALL, DISTANCE TO WALL and RULE VIOLATION were strongly spatially dependent. Centrality and proximity to the goal increased the variables PLAYERS IN WALL, RULE VIOLATIONS and INTERRUPTION TIME, and the ratio of goals scored increased from 5.9% (central far) to 10.9% (central near). In 70.9% of the shots, players preferred a switched laterality, which did not result in a higher success rate. Furthermore, there was no statistical advantage for the defensive team when DISTANCE TO WALL was below 9.15 m or when there was a RULE VIOLATION. Crosses had a success rate (i.e., first controlled ball contact after the cross) of 20.8%. Played with natural laterality, they were 5% more successful than with switched laterality. Crosses from the right side outside the penalty box were 10% more successful than from the left side. Therefore, it might be worthwhile practising the defence of balls coming from this side.  相似文献   

真正的天堂     

高素菊 《海外英语》2007,(3):40-41

你说的那个地方是不是有金子铺的街道和珍珠做的门? 不, 那是地狱。一个人带着他的狗在路上边走边欣赏风景, 突然, 他想起来自己已经死了。他记得他死了, 而且狗也死了几年了。他不知道这条路会把他们带到哪里。  相似文献   

Teaching and research: Rapport or mesalliance     

Michael A. Faia 《Research in higher education》1976,4(3):235-246

In America, the problem has persisted for at least a century: Are teaching and research mutually supportive, or do they tend to detract from one another? The empirical literature (due largely to measurement problems) provides an ambiguous answer, although the more recent studies have produced fairly consistently negative results. Role complementarity may depend on a range of social structural conditions, such as time allocation, whether or not roles are highly specialized, and the values around which roles are organized. In addition, the process of “compensatory selection” may reduce role complementarity as teacher/researchers move through their careers. Data for this study suggest that teaching and research tend to be mutually supportive, especially at schools where research is not emphasized.  相似文献   

Reassessing the People's Choice: Revisiting a Classic and Excavating Lessons for Research About Media and Voting     

Stephen Lacy  Michael Stamm 《Mass Communication and Society》2016,19(2):105-126

This article reassesses The People's Choice by Paul Lazarsfeld, Bernard Berelson, and Hazel Gaudet, one of the foundations of communication and voting behavior research. As with most classics, which are often cited but seldom read, we believe this book has much to teach contemporary social scientists. We return to the original context of the research and use voting data from the period with three broad goals: (a) to find ideas and lessons from this work that generally have been overlooked, (b) to suggest new ways of applying these ideas, and (c) to encourage scholars to engage more with this seminal work to understand ideas that are often overlooked when a complex piece of research is reduced to a brief discussion or passing citation.  相似文献   

Walter Lippmann’s Ghost: An Interview With Michael Schudson     

Michael Schudson 《Mass Communication and Society》2016,19(3):221-229

An esteemed scholar conducts an enlightening examination of the enduring issues of the press as a democratic institution, the professionalization of the journalist, journalism schools, liberalism, and science. This imagined one-on-one conversation with Walter Lippmann is lightly humorous yet offers important insights on the accountability of the government by the press in days gone by and on the accountability of the press to the public in our digital age.  相似文献   

Humanitas Emptor: Reconsidering Recent Trends and Policy in Science Teacher Education     

Dana L. Zeidler  Benjamin C. Herman  Michael P. Clough  Joanne K. Olson  Sami Kahn  Mark Newton 《Journal of Science Teacher Education》2016,27(5):465-476

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Academic socialization,parental educational expectations,and academic self‐efficacy among Latino adolescents     

Fernanda L. Cross  Aixa D. Marchand  Michael Medina  Andrea Villafuerte  Deborah Rivas‐Drake 《Psychology in the schools》2019,56(4):483-496

This study examined the direct association between parental educational expectations and adolescents’ academic self‐efficacy, as well as the moderating influence of parental academic socialization messages. Participants were 148 Latino parent–adolescent dyads with the majority of Mexican origin (80.4%). Most of the parent participants were mothers (85.8%). Adolescents were 13 (46%) or 14 (54%) years of age, and 53% identified as female. Adolescents reported their academic self‐efficacy and perceptions of their parents’ educational expectations; parents reported on their academic socialization messages of shame/pressure and effort regarding academics. The results suggest that, after accounting for parents’ level of education and immigrant status, parental educational expectations were positively associated with adolescent academic self‐efficacy. This association was stronger among adolescents whose parents reported transmitting fewer messages of shame/pressure and academic effort. These results point to the importance of nuances in the content and type of academic socialization messages within Latino families.  相似文献