The influence of pitch dimensions on performance during small-sided and conditioned soccer games     

Luís Vilar  Ricardo Duarte  Pedro Silva  Jia Yi Chow  Keith Davids 《Journal of sports sciences》2013,31(19):1751-1759

Abstract

This study examined the influence of pitch dimensions in small-sided soccer games in shaping opportunities for performers to maintain ball possession, pass to teammates and shoot at goal. Fifteen amateur standard male participants (M = 21.87, σ = 1.96 years) played 5 v 5 small-sided soccer games in three varying pitch conditions (28 m × 14 m, 40 m × 20 m and 52 m × 26 m). Thirty sequences of play in each condition were selected for digitisation using TACTO software, allowing the capture of bi-dimensional displacement coordinate data of all players and the ball. The values of interpersonal distance between all attackers and immediate defenders and the relative distances of defenders to intercept a shot and a pass were computed as dependent variables. Results showed existence of fewer opportunities to maintain ball possession on smaller pitches, compared to medium and larger pitches. Conversely, the different dimensions set to the pitch did not influence opportunities for players to shoot at goal, or to perform passes to other teammates. By examining the specific spatial–temporal relationships of players and key-task constraints, the data from this study explain how effects of manipulating pitch dimensions of small-sided games might enhance opportunities for acquiring specific movement and decision-making skills.  相似文献   

Creatine supplementation does not decrease oxidative stress and inflammation in skeletal muscle after eccentric exercise     

Luciano A. Silva  Camila B. Tromm  Guilherme Da Rosa  Karoliny Bom  Thais F. Luciano  Talita Tuon 《Journal of sports sciences》2013,31(11):1164-1176

Abstract

Thirty-six male rats were used; divided into 6 groups (n = 6): saline; creatine (Cr); eccentric exercise (EE) plus saline 24 h (saline + 24 h); eccentric exercise plus Cr 24 h (Cr + 24 h); eccentric exercise plus saline 48 h (saline + 48 h); and eccentric exercise plus Cr 48 h (Cr + 48h). Cr supplementation was administered as a solution of 300 mg · kg body weight^?1 · day^?1 in 1 mL water, for two weeks, before the eccentric exercise. The animals were submitted to one downhill run session at 1.0 km · h^?1 until exhaustion. Twenty-four and forty-eight hours after the exercise, the animals were killed, and the quadriceps were removed. Creatine kinase levels, superoxide production, thiobarbituric acid reactive substances (TBARS) level, carbonyl content, total thiol content, superoxide dismutase, catalase, glutathione peroxidase, interleukin-1b (IL-1β), nuclear factor kappa B (NF-kb), and tumour necrosis factor (TNF) were analysed. Cr supplementation neither decreases Cr kinase, superoxide production, lipoperoxidation, carbonylation, total thiol, IL-1β, NF-kb, or TNF nor alters the enzyme activity of superoxide dismutase, catalase, and glutathione peroxides in relation to the saline group, respectively (P < 0.05). There are positive correlations between Cr kinase and TBARS and TNF-α 48 hours after eccentric exercise. The present study suggests that Cr supplementation does not decrease oxidative stress and inflammation after eccentric contraction.  相似文献   

A Psychophysiological Assessment of Elite Wrestlers     

John M. Silva III  Barry B. Shultz  Robert W. Haslam  Donald Murray 《Research quarterly for exercise and sport》2013,84(3):348-358

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Technical Reliability Assessment of the Actigraph GT1M Accelerometer     

Pedro Silva  Jorge Mota  Dale Esliger  Gregory Welk 《Measurement in physical education and exercise science》2013,17(2):79-91

The purpose of this study was to determine the reliability of the Actigraph GT1M (Pensacola, FL, USA) accelerometer activity count and step functions. Fifty GT1M accelerometers were initialized to collect simultaneous acceleration counts and steps data using 15-sec epochs. All reliability testing was completed using a mechanical shaker plate to perform six different test conditions in Experiment 1 and 18 test conditions in Experiment 2. The overall intra- and inter-instrument reliability of the GT1M was CV_intra = 2.9% and CV_inter = 3.5% for counts and CV_intra = 1.1% and CV_inter = 1.2% for steps. No batch effects were evident in the 50 GT1Ms. The Actigraph GT1M accelerometer demonstrated good reliability for measuring both counts and steps. However, the ability of the GT1M to consistently detect acceleration at a given acceleration and frequency condition varied widely. Future studies clarifying the filtering limitations and the threshold necessary to detect the occurrence of movement are warranted.  相似文献   

Too little or too much? Parafoveal preview benefits and parafoveal load costs in dyslexic adults     

Susana Silva  Luís Faísca  Susana Araújo  Luis Casaca  Loide Carvalho  Karl Magnus Petersson  Alexandra Reis 《Annals of dyslexia》2016,66(2):187-201

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Stairway to employment? Internships in higher education     

Patrícia Silva  Betina Lopes  Marco Costa  Dina Seabra  Ana I. Melo  Elisabeth Brito  Gonçalo Paiva Dias 《Higher Education》2016,72(6):703-721

This article aims to shed light on the current debate regarding the role of internships in higher education in graduates’ employability. In specific, it analyses empirical data on a large-scale study of Portuguese first-cycle study programmes, in order to explore indicators of the professional value of internships in the employability of higher education graduates. Results demonstrate that study programmes that include internships tend to significantly enhance graduates’ employability, particularly within the universe of polytechnic and public higher education institutions. Besides the instrumental value of internships, the impact of the nature and structure of the internship on the percentage of unemployed graduates are also discussed. Mandatory internships and the inclusion of multiple, shorter internships throughout the degree are negatively associated with unemployment levels. Results indicate work-based learning can be used as a successful strategy to bridge theoretical knowledge and practice and enhance graduate employability. These findings provide important insights for the evaluation and/or the design of internship programmes in higher education.  相似文献   

Planning for Reform-Based Science: Case Studies of Two Urban Elementary Teachers     

Elaine Silva Mangiante 《Research in Science Education》2018,48(1):207-232

The intent of national efforts to frame science education standards is to promote students’ development of scientific practices and conceptual understanding for their future role as scientifically literate citizens (NRC 2012). A guiding principle of science education reform is that all students receive equitable opportunities to engage in rigorous science learning. Yet, implementation of science education reform depends on teachers’ instructional decisions. In urban schools serving students primarily from poor, diverse communities, teachers typically face obstacles in providing reform-based science due to limited resources and accountability pressures, as well as a culture of teacher-directed pedagogy, and deficit views of students. The purpose of this qualitative research was to study two white, fourth grade teachers from high-poverty urban schools, who were identified as transforming their science teaching and to investigate how their beliefs, knowledge bases, and resources shaped their planning for reform-based science. Using the Shavelson and Stern’s decision model for teacher planning to analyze evidence gathered from interviews, documents, planning meetings, and lesson observations, the findings indicated their planning for scientific practices was influenced by the type and extent of professional development each received, each teacher’s beliefs about their students and their background, and the mission and learning environment each teacher envisioned for the reform to serve their students. The results provided specific insights into factors that impacted their planning in high-poverty urban schools and indicated considerations for those in similar contexts to promote teachers’ planning for equitable science learning opportunities by all students.  相似文献   

Contexts for questioning: two zones of teaching and learning in undergraduate science     

Helena Pedrosa-de-Jesus  Betina da Silva Lopes  Aurora Moreira  Mike Watts 《Higher Education》2012,64(4):557-571

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History of education in Brazil: the construction of a knowledge field     

José Gonçalves Gondra  Carlos Eduardo Vieira  Regina Helena Silva Simões  Claudia Engler Cury 《Paedagogica Historica: International Journal of the History of Education》2014,50(6):822-829

This article analyses the general characteristics of the construction of the field of history of education in Brazil. To do so, it highlights the existing historiography and aims to describe the process of institutionalisation of this knowledge field, which, in general terms, has been focused on the area of teacher training. Since the nineteenth century, however, it has also been possible to identify systematic historiographical efforts in Brazil that are not directly related to the school system, but rather to the teaching of and research into the history of education within Brazilian universities. The article addresses the organisation of the field, the ways in which it has been structured and the strategies of academic legitimisation employed to achieve this. These include the regular production of dissertations and doctoral theses, the publication of books and journals, academic events and the creation of research groups and scientific associations, through which research findings have found national and international circulation. This set of indicators creates conditions for an understanding of the expansion and reconfiguration of the field of history of education that began in the 1980s, as well as of the challenges this phenomenon presents to current historiography and teacher training in Brazil.  相似文献   

Enhancing student learning of research methods through the use of undergraduate teaching assistants     

Jessica Crowe  Ryan Ceresola  Tony Silva 《Assessment & Evaluation in Higher Education》2014,39(6):759-775

By using a quasi-experimental design, in this study, we test the effect of undergraduate teaching assistants on student learning. Data were collected from 170 students enrolled in four sections of a quantitative research methods course, two sections without undergraduate teaching assistants and two sections with undergraduate teaching assistants, over two semesters. Results indicate that having undergraduate teaching assistants in the classroom can result in higher student performance. Students in the sections with undergraduate teaching assistants earned higher grades, were more likely to pass the course with a C or higher and performed better on half of the student learning outcomes than students in the sections without an undergraduate teaching assistant. Based on the overwhelmingly positive results on student learning, we would recommend the active use of undergraduate teaching assistants in the classroom, but especially for courses that students find challenging.  相似文献