Dribbling determinants in sub-elite youth soccer players     

Matteo Zago  Andrea Gianluca Piovan  Isabella Annoni  Daniela Ciprandi  F. Marcello Iaia 《Journal of sports sciences》2016,34(5):411-419

Dribbling speed in soccer is considered critical to the outcome of the game and can assist in the talent identification process. However, little is known about the biomechanics of this skill. By means of a motion capture system, we aimed to quantitatively investigate the determinants of effective dribbling skill in a group of 10 Under-13 sub-elite players, divided by the median-split technique according to their dribbling test time (faster and slower groups). Foot-ball contacts cadence, centre of mass (CoM), ranges of motion (RoM), velocity and acceleration, as well as stride length, cadence and variability were computed. Hip and knee joint RoMs were also considered. Faster players, as compared to slower players, showed a 30% higher foot-ball cadence (3.0 ± 0.1 vs. 2.3 ± 0.2 contacts · s^?1, P < 0.01); reduced CoM mediolateral (0.91 ± 0.05 vs. 1.14 ± 0.16 m, P < 0.05) and vertical (0.19 ± 0.01 vs. 0.25 ± 0.03 m, P < 0.05) RoMs; higher right stride cadence (+20%, P < 0.05) with lower variability (P < 0.05); reduced hip and knee flexion RoMs (P < 0.05). In conclusion, faster players are able to run with the ball through a shorter path in a more economical way. To effectively develop dribbling skill, coaches are encouraged to design specific practices where high stride frequency and narrow run trajectories are required.  相似文献   

The effects of physical contact type on the internal and external demands during a rugby league match simulation protocol     

Jonathan P. Norris  Jamie Highton  Stephen F. Hughes  Craig Twist 《Journal of sports sciences》2016,34(19):1859-1866

The aim of this study was to investigate how the type of contact influences physiological, perceptual and locomotive load during a simulated rugby league match. Eleven male university rugby league players performed two trials of the rugby league movement simulation protocol for interchange forwards with a traditional soft tackle bag and a weighted tackle sled to replicate contact demands. The interchange forward-specific simulation was chosen given the contact frequency is higher for this group of players compared to whole match players. Locomotive rate, sprint speed, tackle intensity, heart rate (HR) and rating of perceived exertion were analysed during the first and second bouts that replicated two ~23 min on-field passages. Countermovement jump (CMJ) was measured before and immediately after each trial. More time was spent in heart rate zone between 91 and 100% HR_peak during the first (effect size ± 90% confidence interval: 0.44 ± 0.49) and second bouts (0.44 ± 0.43), and larger (0.6 ± 0.69) decrements in CMJ performance were observed during the sled trial (5.9, s = 4.9%) compared to the bag trial (2.6, s = 5.4%). Changing the type of contact during the match simulation subtly altered both the internal and external loads on participants. Using a standard tackle bag results in faster sprint speed to contact, but lower overall high-intensity running. Conversely, a heavier tackle object increases the internal load and results in greater lower limb neuromuscular fatigue as reflected by the decrease in CMJ performance.  相似文献   

Cuba’s Challenges Hosting the 1991 Pan-American Games and the Spectacle of the Revolution’s ‘Soft Power’     

Thomas F. Carter 《国际体育史杂志》2016,33(1-2):186-202

Abstract

This paper examines the confluence of global, regional, and national politics in the lead up to the 1991 Pan-American Games hosted by Cuba. Cuba’s contentious selection as host was wholly underpinned by the international politics of the time. Once selected, the preparations for the Games in Havana were surrounded by an unprecedented domestic economic crisis fueled by shifts in global politics. This paper analyzes how international politics informed the hosting of the 1991 Pan-American Games, and shaped the political challenge the Cuban government faced in hosting such an event. The Revolution’s use of sport domestically and internationally came to the forefront in its efforts as host and the results of those efforts proved to be providential given the emerging political economic contexts during and in the ensuing years after the Games.  相似文献   

Predicaments,Problems, Puzzles,and Paradoxes in Educational Research*     

Harry S. Broudy 《Educational theory》1983,33(1):33-39

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Sign and phonology     

Moores DF 《American annals of the deaf》2001,146(1):3-4

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Some correlates of the choice of educational streams in Israeli High Schools     

Avi Hofstein  Ruth Ben-Zvi  David Samuel  Richard F. Kempa 《科学教学研究杂志》1977,14(3):241-247

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Classroom observation systems in context: A case for the validation of observation systems     

Liu  Shuangshuang  Bell  Courtney A.  Jones  Nathan D.  McCaffrey  Daniel F. 《Educational Assessment, Evaluation and Accountability》2019,31(1):61-95

Educational Assessment, Evaluation and Accountability - Researchers and practitioners sometimes presume that using a previously “validated” instrument will produce “valid”...  相似文献   

About this issue     

Edward F. Iwanicki 《Educational Assessment, Evaluation and Accountability》1990,3(3):203-203

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A Self-Regulated Learning Approach to Teaching Educational Psychology     

Nelson F. Du Bois  Richard K. Staley 《Educational Psychology Review》1997,9(2):171-197

In this paper, we describe an undergraduate educational psychology course that utilizes self-regulated learning as the organizing principle. The course aims to facilitate students' development in self-regulated learning and to promote students' understanding of how to embed instruction for self-regulated learning strategies into classroom teaching. In the first section of the paper, we develop the rationale for this position and identify underlying assumptions we believe should guide the development and implementation of such a program. In the second section of the paper, we demonstrate how we have incorporated these assumptions in a basic educational psychology course.  相似文献   

The Inclusion of Informal Environments in Science Teacher Preparation     

Olson  Joanne K.  Cox-Petersen  Anne M.  McComas  William F. 《Journal of Science Teacher Education》2001,12(3):155-173

Journal of Science Teacher Education -  相似文献