Differences in the utilisation of active power in squat and countermovement jumps     

Damián Ferraro  Gabriel Fábrica 《European Journal of Sport Science》2017,17(6):673-680

The aim of this article was to understand how active power is used in squat and countermovement jumps. A simple empirical model comprising a mass, a spring, an active element and a damper, together with an optimisation principle, was used to identify the mechanical factors that maximise performance of jumps without countermovement (squat jumps, SJ) and with countermovement (CMJ). Twelve amateur volleyball players performed SJ from two initial positions and CMJ with two degrees of counterbalancing, while kinematic data were collected (jump height, push-off duration and position of the centre of mass). The model adjusted well to real data of SJ through all the impulse phase, and slightly less adequately at the end of this phase for CMJ. Nevertheless, it provides a satisfactory explanation for the generation and utilisation of active power for both type of jumps. On average, the estimated power of the active elements, the spring, and the damper were greater in the SJ. Based upon the result obtained with this model, we suggest that active power is best evaluated with SJ. The reason for this is that, during this kind of jump, the elements associated with the damper consume much of the energy produced by the active elements. The participation of the elements that consume the energy generated by the active elements is less in CMJ than in SJ, allowing for a better utilisation of this energy. In this way it is possible to achieve a better performance in CMJ with less active power.  相似文献   

Rome's World: The Peutinger Map Reconsidered     

Emilia Mataix Ferrándiz 《Al-Masaq: Islam & the Medieval Mediterranean》2017,29(1):84-86

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Are gait characteristics and ground reaction forces related to energy cost of running in elite Kenyan runners?     

J. Santos-Concejero  N. Tam  D. R. Coetzee  J. Oliván  T. D. Noakes  R. Tucker 《Journal of sports sciences》2017,35(6):531-538

The aim of this study was to determine whether gait cycle characteristics are associated with running economy in elite Kenyan runners. Fifteen elite Kenyan male runners completed two constant-speed running sets on a treadmill (12 km ·h^?1 and 20 km ·h^?1). VO₂ and respiratory exchange ratio values were measured to calculate steady-state oxygen and energy cost of running. Gait cycle characteristics and ground contact forces were measured at each speed. Oxygen cost of running at different velocities was 192.2 ± 14.7 ml· kg^?1· km^?1 at 12 km· h^?1 and 184.8 ± 9.9 ml· kg^?1· km^?1 at 20 km· h^?1, which corresponded to a caloric cost of running of 0.94 ± 0.07 kcal ·kg^?1·km^?1 and 0.93 ± 0.07 kcal· kg^?1· km^?1. We found no significant correlations between oxygen and energy cost of running and biomechanical variables and ground reaction forces at either 12 or 20 km· h^?1. However, ground contact times were ~10.0% shorter (very large effect) than in previously published literature in elite runners at similar speeds, alongside an 8.9% lower oxygen cost (very large effect). These results provide evidence to hypothesise that the short ground contact times may contribute to the exceptional running economy of Kenyan runners.  相似文献   

Live Body: An interview with Anne Emmanuelle Berger     

Anne Emmanuelle Berger  Lenka Vráblíková 《Parallax》2019,25(2):119-136

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Community sport and social inclusion: international perspectives     

Hebe Schaillée  Reinhard Haudenhuyse  Lieve Bradt 《Sport in Society》2019,22(6):885-896

Abstract

This opening article examines the relationship between community sport and social inclusion in research and practice. We discuss the notion of community sport, its multifarious meanings and diverse applications in different parts of the world. We further explore the conceptual and practical links between community sport and different conceptions of social inclusion. In doing so, the article draws together key themes, issues and debates addressed in the collection of articles in this special issue. We conclude by formulating implications and directions for future research and practice.  相似文献   

Virtual Microscopy as a Learning Tool in Brazilian Medical Education     

Fernanda Somera dos Santos  Mariana Kiomy Osako  Gleici da Silva Castro Perdoná  Márcia Gaião Alves  Katiuchia Uzzun Sales 《Anatomical sciences education》2021,14(4):408-416

Virtual microscopy (VM) is a widely used teaching method in Medical Education in many developed countries. In Brazil, however, this is not the case for most medical schools, considering Brazilian social inequality and uneven access to technology. Recently, the Covid-19 pandemic has also challenged Universities to seek and make a transition toward more effective methods of full-time online education. Thus, the main goal of this work was to verify student's perception and academic performance, assessed upon VM implementation in a Brazilian Medical School. Ribeirao Preto Medical School students answered a 26-question survey with regards to optical microscopy (OM) and VM. Academic performance was compared between participants that were (year of 2019) or were not (year of 2015) exposed to VM. Taken the results together, subjective impressions such as handling, suitability, learning effectiveness, and pleasure using the tools, have shown a higher score for virtual microscopy (median = 29), when compared to optical microscopy (median = 24) with a P-value < 0.001 by Wilcoxon rank test, upon measurement using an ordinal scale. Regarding academic performance, no statistically significant differences were found between groups (P-value = 0.38, Cohen's d = 0.19). Therefore, VM proved to be adequate to the Brazilian medical education in light of Brazilian social contexts and Covid-19 pandemic.  相似文献   

Coeducational and single-sex physical education: students’ situational interest in learning tasks centred on technical skills     

Vanessa Lentillon-Kaestner  Cédric Roure 《Physical Education & Sport Pedagogy》2019,24(3):287-300

Background: A student’s choice to engage in a learning task is highly related to the student’s environmental stimuli and his or her perception of interest. From this perspective, the construct of situational interest (SI) has been used to interpret students’ motivation in task engagement. SI is assumed to be transitory, environmentally activated, and context specific. It has been conceptualized as a multidimensional construct with five dimensions: instant enjoyment, exploration intention, attention demand, novelty, and challenge. Few prior studies have compared SI between girls and boys in physical education (PE) contexts, and these studies have offered contrasting findings. They were conducted in coeducational (coed) or single-sex contexts and used learning tasks centred on a variety of outcomes: technical or tactical skills, creativity and cultural understanding.

Purpose: In the context of the debate on single-sex and coed classes in PE, this study aimed to estimate the effects of single-sex and coed PE classes on students’ situational interest (SI) within learning tasks centred on technical skills. The researchers decided to study learning tasks centred on the development of students’ technical skills, since these tasks are often used by teachers in PE.

Participants: The sample consisted of 177 Swiss secondary school students, aged 11–17 years (M?=?14.07, SD?=?1.41, 96 boys, 81 girls).

Data collection: The students completed the French 15-item SI Scale after practising a technical learning task in single-sex and coed PE contexts. The researchers chose five physical activities (i.e. athletics, basketball, dance, gymnastics, and volleyball), which are commonly taught in the state of Vaud (Switzerland) and provide a balance between masculine and feminine activities.

Data analysis: A two-way repeated-measures MANOVA was performed to examine the main and interaction effects of student sex and class sex composition on the five SI dimensions.

Findings: The results showed a main effect of class sex composition on student SI but no main effect of student sex and no interaction effect of student sex and class sex composition. More precisely, the scores for three SI dimensions (i.e. instant enjoyment, exploration intention, and attention demand) were higher in the coed context than in the single-sex context.

Conclusions: This study encourages teachers to propose coed PE classes to enhance students’ motivation and engagement when practising learning tasks centred on technical skills. This study offers supplementary evidence of the teacher’s role in promoting student SI. Beyond accounting for students’ dispositional factors (e.g. sex), PE teachers can significantly impact students’ SI in technical learning tasks through instructional choices.  相似文献   

Measuring allocative efficiency in Cultural Economics: the case of “Fundación Princesa de Asturias” (The Princess of Asturias Foundation)     

Víctor Fernández-Blanco  Ana Rodríguez-Álvarez 《Journal of Cultural Economics》2018,42(1):91-110

The literature on Cultural Economics provides us with some examples for the measurement of technical efficiency. However, there are few case studies dedicated to the analysis of allocative efficiency. The aim of this paper is to fill this gap by incorporating a methodology that analyses both technical and allocative efficiency. We use the Shephard’s distance function, particularly suitable when affronted with non-profit-making firms or institutions that are not interested in cost minimization. As an empirical application, we analyse the efficiency of Fundación Princesa de Asturias (PAF), a Spanish non-governmental organization devoted to promoting the cultural, scientific and humanistic values of universal heritage, the period of study being 1988–2012. Our findings suggest that PAF could have used 7% less inputs to achieve the same level of output. On the other hand, we have found allocative inefficiency. Concretely, the input for other expenditures appears to have been over-utilized in relation to both the inputs for labour and current assets, with labour in turn being over-utilized in relation to current assets. Moreover, our results indicate that both technical and allocative efficiency have clearly improved during the period analysed. In summary, our empirical application shows how distance function methodology can be successfully implemented to measure allocative efficiency in cultural firms and institutions.  相似文献   

Mastery motivation,parenting, and school achievement among Hungarian adolescents     

Józsa  Krisztián  Kis  Noémi  Barrett  Karen Caplovitz 《European Journal of Psychology of Education - EJPE》2019,34(2):317-339

European Journal of Psychology of Education - Children’s motivation to master challenging tasks is an important predictor of school success, and yet, such motivation declines during...  相似文献   

Orthographic-Phonological Mapping and the Emergence of Visual Expertise for Print: A Developmental Event-Related Potential Study     

Vera Varga  Dénes Tóth  Valéria Csépe 《Child development》2020,91(1):e1-e13

The N1 effect is an electrophysiological marker of visual specialization for print. The phonological mapping hypothesis (Maurer & McCandliss, 2007) posits that the left-lateralized effect reflects grapheme-phoneme integration. In this event-related potential study, first (age = 7.06 years, N = 32) and third-grade readers (age = 9.29 years, N = 28) were presented with pairs of pseudowords and Armenian character strings in a novel implicit same-different paradigm. To test the phonological mapping hypothesis, stimuli were presented in visual-only and audiovisual conditions. The results demonstrated that tuning for print already emerges in first grade. Moreover, the parallel presentation of auditory stimuli enhanced the N1 effect suggesting a role of orthographic-phonological mapping in the development of specialization for print.  相似文献