The effects of static stretching on speed and agility: One or multiple repetition protocols?     

Alexandra Avloniti  Ioannis G. Fatouros  Maria Protopapa  Ioannis Athanailidis  Christina Avloniti 《European Journal of Sport Science》2016,16(4):402-408

Although static stretching (SS) is utilized during warm-up before training and competition, the results about its effects on performance remain controversial. We examined whether performing a stretch of short-to-moderate duration (<60 sec) in a single repetition produces a similar or different effect on speed and agility performance from the effect which is produced while performing the same stretch in multiple repetitions of the same total duration. According to a repeated measurement design, 40 trained males were randomly assigned to either (1) a single repetition group or (2) a multiple repetition group. The participants in each group performed five trials: a control trial (no stretches were performed) and four experimental trials of SS protocols consisting of five exercises performed at either 20 sec (2 × 10 in the second group), 30 sec (3 × 10 in the second group), 40 sec (4 × 10 in the second group) or 60 sec (6 × 10 in the second group) of total duration. A two-way repeated measures analysis of variance showed that the participants in both group improved their speed performance in response to the 20-sec trial, whereas agility remained unaffected. Data analysis also revealed that the repetition number did not affect speed and agility performance. These data suggest that SS of short duration (<30 sec) may actually improve acute speed performance, whereas SS of moderate duration may not hamper speed and agility performance. Moreover, the effects of SS protocols are related to the total duration of each exercise and not to the number of repetitions in which each exercise is performed.  相似文献   

One hundred and fifty years of sprint and distance running – Past trends and future prospects     

Martin Weiss  Alexandra Newman  Ceri Whitmore  Stephan Weiss 《European Journal of Sport Science》2016,16(4):393-401

Sprint and distance running have experienced remarkable performance improvements over the past century. Attempts to forecast running performances share an almost similarly long history but have relied so far on relatively short data series. Here, we compile a comprehensive set of season-best performances for eight Olympically contested running events. With this data set, we conduct (1) an exponential time series analysis and (2) a power-law experience curve analysis to quantify the rate of past performance improvements and to forecast future performances until the year 2100. We find that the sprint and distance running performances of women and men improve exponentially with time and converge at yearly rates of 4% ± 3% and 2% ± 2%, respectively, towards their asymptotic limits. Running performances can also be modelled with the experience curve approach, yielding learning rates of 3% ± 1% and 6% ± 2% for the women's and men's events, respectively. Long-term trends suggest that: (1) women will continue to run 10–20% slower than men, (2) 9.50 s over 100 m dash may only be broken at the end of this century and (3) several middle- and long-distance records may be broken within the next two to three decades. The prospects of witnessing a sub-2 hour marathon before 2100 remain inconclusive. Our results should be interpreted cautiously as forecasting human behaviour is intrinsically uncertain. The future season-best sprint and distance running performances will continue to scatter around the trends identified here and may yield unexpected improvements of standing world records.  相似文献   

Theory of mind in dogs?: examining method and concept     

Horowitz A 《Learning & behavior》2011,39(4):314-317

In line with other research, Udell, Dorey, and Wynne’s (in press) finding that dogs and wolves pass on some trials of a putative theory-of-mind test and fail on others is as informative about the methods and concepts of the research as about the subjects. This commentary expands on these points. The intertrial differences in the target article demonstrate how critical the choice of cues is in experimental design; the intersubject-group differences demonstrate how life histories can interact with experimental design. Even the best-designed theory-of-mind tests have intractable logical problems. Finally, these and previous research results call for the introduction of an intermediate stage of ability, a rudimentary theory of mind, to describe subjects’ performance.  相似文献   

Toward an Integrated Framework of Multiple Text Use     

Alexandra List 《教育心理学家》2019,54(1):20-39

We introduce the Integrated Framework of Multiple Texts to understand how students use and form connections between multiple texts to accomplish personal or task goals. The Integrated Framework of Multiple Texts conceptualizes students’ multiple text use as unfolding over the course of three stages—preparation, execution, and production. In the preparation stage of the framework, individual difference factors and students’ task analysis result in learners’ adoption of a default stance, or a general orientation, toward multiple text use. During the execution stage of the framework, students engage in a variety of behavioral, cognitive, and metacognitive/regulatory strategies to develop cross-textual links and to integrate information across multiple texts. The execution stage concludes with students’ development of a variety of affective and cognitive outcomes as a consequence of text access. Finally, in the production stage of the framework, students draw on these affective and cognitive outcomes to develop external, often written products.  相似文献   

Exit cards: creating a dialogue for continuous evaluation     

Mazna Patka  Jennifer Wallin-Ruschman  Tenille Wallace  Candice Robbins 《Teaching in Higher Education》2016,21(6):659-668

This study explored the use of Exit Cards, which are formative evaluations of student knowledge and instruction undertaken at every class meeting. Its results are based on Exit Card data from two undergraduate research methods courses. Thematic analysis indicated that students used Exit Cards to communicate (1) what they learned, (2) challenges with course material, (3) experiences with peers, (4) requests for help, (5) challenges with coping, and (6) successes. While the present study is an initial exploration of the use of Exit Cards, it contributes to knowledge on the utilization of informal formative assessments.  相似文献   

Black School,White School: Racism and Educational (Mis)Leadership. Jeffrey S. Brooks. New York,NY: Teachers College Press, 2012, 153 pp., $28.95     

Lucy E. Bailey  Alexandra J. Holter 《Educational Studies A Journal of the American Educational Studies Association》2016,52(4):381-384

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Digital Work Practices: Affordances in Design Education     

Alexandra Crosby  Kane Pham  J. Fiona Peterson  Thomas Lee 《The International Journal of Art & Design Education》2020,39(1):22-37

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A Multipart Project Planning and Tracking Exercise     

Thomas R. Robbins 《Decision Sciences Journal of Innovative Education》2019,17(2):104-125

Project Management is an important skill for business students to develop. Although project‐oriented activity is very common, the success rate for projects is poor. Many projects fail due to poor planning. This article describes a multipart class exercise used to teach elements of a project management methodology to undergraduate and graduate business students. Over the course of the eight‐part exercise, student teams iteratively develop a project plan and Gantt chart, an initial and detailed project charter, a variance analysis model, and a status report. Students are taught an iterative top‐down planning process using a technique we term the ODW (Objectives–Deliverables–Workplan) model. Students are introduced to Microsoft Project and use the tool to develop a project plan that becomes part of a more detailed Project Charter. In the final stages of the exercise, students collect results, update their plan, and produce a project status report.  相似文献   

Gender equality in the Olympic Movement: not a simple question,not a simple answer     

Alexandra Avena Koenigsberger 《体育哲学杂志》2017,44(3):329-341

This article explores the strategies followed by the International Olympic Committee for the achievement of gender equality. It is argued that this international body can go beyond simply adopting an equality of opportunities approach to gender equality. It suggests which other strategies can be incorporated for which it draws on the different ways of understanding gender equality in gender political theory.  相似文献   

Skating start propulsion: three-dimensional kinematic analysis of elite male and female ice hockey players     

Jaymee R. Shell  Shawn M. K. Robbins  Philippe C. Dixon  Philippe J. Renaud  René A. Turcotte  Tom Wu 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(3):313-324

The forward skating start is a fundamental skill for male and female ice hockey players. However, performance differences by athlete’s sex cannot be fully explained by physiological variables; hence, other factors such as skating technique warrant examination. Therefore, the purpose of this study was to evaluate the body movement kinematics of ice hockey skating starts between elite male and female ice hockey participants. Male (n = 9) and female (n = 10) elite ice hockey players performed five forward skating start accelerations. An 18-camera motion capture system placed on the arena ice surface captured full-body kinematics during the first seven skating start steps within 15 meters. Males’ maximum skating speeds were greater than females. Skating technique sex differences were noted: in particular, females presented ~10° lower hip abduction throughout skating stance as well as ~10° greater knee extension at initial ice stance contact, conspicuously followed by a brief cessation in knee extension at the moment of ice contact, not evident in male skaters. Further study is warranted to explain why these skating technique differences exist in relation to factors such as differences in training, equipment, performance level, and anthropometrics.  相似文献