Neuromuscular and technical abilities related to age in water-polo players     

Fabio De Siati  Guillaume Laffaye  Giorgio Gatta  Antonio Dello Iacono  Johnny Padulo 《Journal of sports sciences》2016,34(15):1466-1472

Testing is one of the important tasks in any multi-step sport programme. In most ball games, coaches assess motor, physical and technical skills on a regular basis in early stages of talent identification in order to further athletes’ development. The purpose of the study was to investigate anthropometric variables and vertical jump heights as a free throw effectiveness predictor in water-polo players of different age groups. Two hundred and thirty-six young (10–18 years) male water-polo players partitioned into three age groups underwent anthropometric variables’ measures and squat- and countermovement-jump tests, and performed water-polo free throws. Anthropometric variables, vertical jump heights and throw speed – as a proxy for free throw effectiveness – resulted different over age groups. Particularly, throw speed changed from 9.28 to 13.70 m · s^?1 (+48%) from younger to older players. A multiple-regression model indicated that body height, squat-jump height and throw time together explain 52% of variance of throw speed. In conclusion, tall height, high lower limb power and throwing quickness appeared to be relevant determinants for effective free throws. Such indications can help coaches during talent identification and development processes, even by means of novel training strategies. Further research is needed over different maturity statuses.  相似文献   

The nexus between college choice and persistence   总被引：2，自引：3，他引：2  

Edward P. St. John  Michael B. Paulsen  Johnny B. Starkey 《Research in higher education》1996,37(2):175-220

Initial student commitments have long been considered an influence on persistence, but the reasons why students choose to attend a college have seldom been considered as dimensions of initial commitments that could influence persistence processes and outcomes. This study used NPSAS-87 to examine the influence of finance-related reasons for choosing a college on persistence decisions. The findings include (1) finance-related choices have direct and indirect influences on whether students persist in college; and (2) market-based, monetary measures of financial aid, tuition costs, housing costs, and other living costs have a substantial direct effect on persistence.  相似文献   

Temporal specificity of training: intra-day effects on biochemical responses and Olympic-Weightlifting performances     

Achraf Ammar  Hamdi Chtourou  Khaled Trabelsi  Johnny Padulo  Mouna Turki  Kais El Abed 《Journal of sports sciences》2015,33(4):358-368

The aim of this study was to investigate the performance of an Olympic-Weightlifting session training at three times of the day on the performance related to biochemical responses. Nine weightlifters (21 ± 0.5 years) performed, in randomised order, on three Olympic-Weightlifting training (snatch, clean and jerk) sessions (08:00 a.m., 02:00 p. m., 06:00 p. m.). Blood samples were collected: before, 3 min and 48 h after each training session. Haematological parameters and markers of muscle injury were assessed. Resting oral temperature and rating of perceived exertion (RPE) were also assessed during each session. ANOVA showed that the performance was better (P < 0.001) at 02:00 p. m. with a less RPE (P < 0.01) compared to the morning and the evening sessions while there was higher (P < 0.05) oral temperature at 06:00 p. m. versus 08:00 a.m. and 02:00 p. m. Muscle damage changed immediately (without significant effect after 48 h) after the training sessions with lower values ??in the evening compared to the morning. In conclusion, the afternoon training is more effective than morning or evening sessions for weightlifters. Therefore, coaches and weightlifters should be advised to schedule their training session in the afternoon hour.  相似文献   

Spillover effects in environmental behaviors,across time and context: a review and research agenda     

Andreas Nilsson  Magnus Bergquist  Wesley P. Schultz 《Environmental Education Research》2017,23(4):573-589

When implementing environmental education and interventions to promote one pro-environmental behavior, it is seldom asked if and how non-target pro-environmental behaviors are affected. The spillover effect proposes that engaging in one behavior affects the probability of engagement or disengaging in a second behavior. Therefore, the positive spillover effect predicts that interventions targeting one specific behavioral have the capacity to promote non-targeted and/or future pro-environmental behaviors. However, the negative spillover effect predicts that engaging in a first pro-environmental behavior will prevent or decrease a second pro-environmental behavior. Since the theoretical and empirical basis for positive and negative spillover effects are not sufficiently understood, the present paper (1) suggests a distinction between behavioral, temporal, and contextual spillovers (2) reviews the existing spillover research literature across a variety of environmental domains, (3) presents potential moderators governing the direction of spillover effects, and finally (4) discuss techniques to promote pro-environmental spillovers.  相似文献   

How shall i compare thee? Comparing the prudential value of actual virtual friendship     

Johnny Hartz S?raker 《Ethics and Information Technology》2012,14(3):209-219

It has become commonplace to hold the view that virtual surrogates for the things that are good in life are inferior to their actual, authentic counterparts, including virtual education, virtual skill-demanding activities and virtual acts of creativity. Virtual friendship has also been argued to be inferior to traditional, embodied forms of friendship. Coupled with the view that virtual friendships threaten to replace actual ones, the conclusion is often made that we ought to concentrate our efforts on actual friendships rather than settle for virtual replacements. The purpose of this paper is to offer a balanced and empirically grounded analysis of the relative prudential value of actual and virtual friendship. That is, do actual and virtual friendships differ when it comes to enhancing our subjective well-being? In doing so, I will discuss a number of presuppositions that lie behind common criticisms of virtual friendship. This will include, among other considerations, their potential for replacing actual friendship, as well as the possibility for self-disclosure, trust, sharing and dynamic spread of happiness in virtual worlds. The purpose is not to arrive at a firm, normative conclusion, but rather to introduce a number of considerations that we should take into account in our individual deliberations over which role virtual friendships ought to have in our unique life situations.  相似文献   

What do we know and where do we go? Formative assessment in developing student teachers’ professional learning of teaching science     

Pernilla Nilsson 《Teachers and Teaching》2013,19(2):188-201

In the context of teacher education, it could well be suggested that assessment activities that build on formative interactions between student teachers and teacher educators might offer new windows into better understanding teaching and learning. This paper presents findings from a study into a primary science teacher education initiative that seeks to build the foundations on which 24 primary science student teachers, through the use of formative assessment of their science teaching and learning, can begin developing their pedagogical content knowledge (PCK). In the project, formative assessment consists of activities used by teacher educators to stimulate interactions, self- and peer-assessment in order to provide insights into how student teachers develop their PCK during a semester. Content Representations (CoRes), were used as a tool to unpack the student teachers’ approach to teaching a science topic and the reasons for that approach. The results indicate that the use of CoRes, together with subsequent self-assessment and formative interactions with teacher educators and peers, do have the potential for PCK development for student teachers. The results further highlight the need for developing reliable and valid tools for capturing and assessing student teachers’ PCK in pre-service teacher education.  相似文献   

Role of exteroceptive background context in taste-aversion conditioning and extinction     

Trevor Archer  Per-Olow Sjödén  Lars-Göran Nilsson  Ned Carter 《Learning & behavior》1979,7(1):17-22

In two experiments, saccharin (CS) and lithium chloride (US) were paired in a context consisting of specific visual, auditory, tactual, and olfactory cues. The saccharin aversion was then extinguished in a context free from conditioning-context cues. Later, saccharin preference tests were given in the presence and absence of these cues. The results indicated that the background cues of the conditioning trial controlled the amount of saccharin drunk on extinction trials, and, furthermore, that extinction of the taste aversion was context specific; i.e., groups given extinction trials in a different (from conditioning) context retained their saccharin aversion in the conditioning context only. The results indicate an important role played by the exteroceptive context in taste-aversion conditioning.  相似文献   

Different ways in which students handle chance encounters in the explorative setting of a dice game     

Per Nilsson 《Educational Studies in Mathematics》2007,66(3):293-315

The purpose of this study is to investigate the ways in which Swedish seventh grade students (12 and 13 years old) handle chance encounters. Four groups of students working in pairs participated in the study. In the group discussions, which were tape-recorded and fully transcribed, the students were encouraged to explore strategies for winning a specifically designed dice game based on the sum of two dice. The dice game included four different set-ups of dice designed to bring to the fore different aspects of probability modelling and to offer the student the opportunity to encounter small differences in the mathematical structure of the sample space and of the probability distribution between the four different set-ups. The study describes strategies that the students use when confronted with these different set-ups, what their activities imply in terms of resources in handling random phenomena and what the dice game offers in terms of opportunities for learning probability. In order to explain such meaning-making processes the students’ activities are viewed from a perspective that takes into consideration how the students’ understanding varies with their interpretations of the situation they are confronted with, i.e., how they contextualize the different set-ups of the dice game. The results show how the students, during the course of the game, reorganize their interpretations of the mathematical content confronting them, and how a variation of guiding principles becomes the object of exploration. Approaches of extremes and a number model are described as a means for the students to identify and assign probabilities for the total of two dice.  相似文献   

Why Inquiry? Primary Teachers’ Objectives in Choosing Inquiry- and Context-Based Instructional Strategies to Stimulate Students’ Science Learning     

Susanne Walan  Pernilla Nilsson  Birgitta Mc Ewen 《Research in Science Education》2017,47(5):1055-1074

Studies have shown that there is a need for pedagogical content knowledge among science teachers. This study investigates two primary teachers and their objectives in choosing inquiry- and context-based instructional strategies as well as the relation between the choice of instructional strategies and the teachers’ knowledge about of students’ understanding and intended learning outcomes. Content representations created by the teachers and students’ experiences of the enacted teaching served as foundations for the teachers’ reflections during interviews. Data from the interviews were analyzed in terms of the intended, enacted, and experienced purposes of the teaching and, finally, as the relation between intended, enacted, and experienced purposes. Students’ experiences of the teaching were captured through a questionnaire, which was analyzed inductively, using content analysis. The results show that the teachers’ intended teaching objectives were that students would learn about water. During the enacted teaching, it seemed as if the inquiry process was in focus and this was also how many of the students experienced the objectives of the activities. There was a gap between the intended and experienced objectives. Hardly any relation was found between the teachers’ choice of instructional strategies and their knowledge about students’ understanding, with the exception that the teacher who also added drama wanted to support her students’ understanding of the states of water.  相似文献   

‘A Spearhead into the Future'—Swedish comprehensive school reforms in foreign scholarly literature 1950‐80     

Ingrid Nilsson 《比较教育学》1989,25(3):357-362

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