Effects of quality of opposition and match status on technical and tactical performances in elite volleyball

The aim of this study was to assess the effects of quality of opposition and match status on technical and tactical volleyball performances, as measured by block, attack, serve, and set actions related to the tasks, space, players, and efficacy of selected game actions. Twenty-five matches from the men's World Cup 2007 were notated and through cluster analysis were classified as "high" (HIGH), "intermediate" (INT) or "low" (LOW) quality. The difference between points scored and points allowed was used to define match status. Multinomial logistic regression identified an association of match status with: set direction (likelihood ratio test [LRT]?=?15.5, P?=?0.017) and block typology (LRT?=?9.6, P?=?0.047) in HIGH vs. HIGH matches; attack player (LRT?=?17.4, P?=?0.026) and block typology (LRT?=?9.2, P?=?0.010) in LOW vs. LOW matches; and serve type (LRT?=?17.4, P?=?0.002), block strategy (LRT?=?53.7, P?<0.001), and serve efficacy (LRT?=?26.0, P?=?0.001) in HIGH vs. LOW matches. Results suggest that volleyball teams took more risky decisions in unbalanced situations. They also carried less risk through technical and tactical decisions in balanced and moderate situations whether they had the advantage or not. Therefore, strategic behaviour was affected by the interaction of quality of opposition and match status, providing a better understanding of volleyball game performance and new insights for practice, competition, and research.     

Portugal and the Mediterranean trade: A Prelude to the discovery of the “new world”

Before the century of great discoveries, and during most of the fifteenth century, the Portuguese developed important commercial activity in the Mediterranean. This is the central issue of this article as seen through two themes: the first is an assessment of the Portuguese organization of Mediterranean trade, with special attention given to the foodstuffs which were, and continued to be, a feature of such trade; and second, is to observe how Portuguese faced competition from others nations’ merchants in the region. The study of these two aspects will provide a better understanding of the re-orientation of Portuguese trade towards the Atlantic.     

No effect of HMB or α-HICA supplementation on training-induced changes in body composition

β-hydroxy-β-methylbutyrate (calcium: HMB-Ca and free acid: HMB-FA) and α-hydroxyisocaproic acid (α-HICA) are leucine metabolites that have been proposed to improve body composition and strength when combined with resistance exercise training (RET). In this double-blind randomized controlled pragmatic trial, we evaluated the effects of off-the-shelf supplements: α-HICA, HMB-FA and HMB-Ca, on RET-induced changes in body composition and performance. Forty men were blocked randomized to receive α-HICA (n?=?10, fat-free mass [FFM]?=?62.0?±?7.1?kg), HMB-FA (n?=?11, FFM?=?62.7?±?10.5?kg), HMB-Ca (n?=?9, FFM?=?65.6?±?10.1?kg) or placebo (PLA; n?=?10, FFM?=?64.2?±?5.7?kg). The training protocol consisted of a whole-body resistance training routine, thrice weekly for 8 weeks. Body composition was assessed by dual-energy x-ray absorptiometry (DXA) and total body water (TBW) by whole-body bioimpedance spectroscopy (BIS), both at baseline and at the end of weeks 4 and 8. Time-dependent changes were observed for increase in trunk FFM (p?相似文献   

Risk Society and Science Education

Science & Education - The current COVID-19 pandemic raises reflection on the new roles of science education in citizen education in a world characterized by civilization risks, derived from the...     

How Do we Measure Implementation of Inclusive Education in the Pacific Islands? A Process for Developing and Validating Disability-Inclusive Indicators

In recent years, countries of the Pacific have been moving strongly towards enhancing inclusive educational practices within a previously segregated education system. Through the Pacific Education Development Framework (PEDF) approved by 14 Pacific Island Education Ministers in 2009, the implementation of regional policies of inclusive education is a priority. To ensure that progress is measurable, these countries have been working collaboratively with several Australian institutions to develop a set of contextually appropriate indicators for measuring disability-inclusive education. This article describes the process adopted in developing these indicators and initial findings regarding the key outcomes. The research is guided by three key principles of collaboration, a need for systemic change and ‘nothing about us without us’. The process adopts a three-stage approach which is outlined and key issues and implications discussed.     

Latent learning in the work place: the placement experiences of student-coaches

The aim of this study was to investigate the work-based internship experiences of eight student-coaches. This was particularly in terms of what precisely such coaches learned within the practical context, and how they engaged with unexpected situational events. The methods employed within the project included focus group interviews and participant observation. In particular, the student-coaches were both interviewed and observed over the course of a nine-month sporting season, with each phase of the research informing the next. The subsequent data were primarily subject to a thematic analysis. The findings of the study were organized under four principal themes: (1) the reality shock felt by the student-coaches in terms of the gap between what they expected and what they experienced; (2) the lack of respect demonstrated by the organizational head coaches for the students; (3) the students’ response in terms of developing their micro-political literacy; and (4) the social price paid by the student-coaches in adopting such action. The results point to the limitations of student learning within high-performance sporting environments. In this respect, the student-coaches’ experiences were not what was expected or desired. Despite this, many valuable and relevant lessons were learned. These related to developing students’ micro-political literacy; necessary knowledge for any neophyte coaches trying to establish bone-fide situational roles.     

Mediating Peer Teaching for Learning Games: An Action Research Intervention Across Three Consecutive Sport Education Seasons

Purpose: The purpose of this study was to provide an integrated analysis of a teacher’s peer-teaching mediation strategies, the student-coaches’ instruction, and the students’ gameplay development across 3 consecutive seasons of sport education. Method: Twenty-six 7th-grade students participated in 3 consecutive sport education seasons of invasion games (basketball, handball, and soccer). The research involved 3 action research cycles, 1 per season, and each cycle included the processes of planning, acting and monitoring, reflecting, and fact finding. Data collection consisted of videotape and audiotape records of all 47 lessons, a reflective field diary kept by the first author in the role of teacher-researcher, and a total of 24 semistructured focus-group interviews. Trustworthiness criteria for assuring the quality of qualitative research included extensive data triangulation, stakeholders’ crosschecking, and collaborative interpretational analysis. Results: Through the application of systematic preparation strategies, student-coaches were able to successfully conduct team instruction that resulted in students’ tactical development and improved performance. Aspects such as the study of predominant configurations of players’ gameplay and similar tactical principles across games within the same category prevented a setback in the complexity of the learning content addressed at the beginning of each season. Players also showed an increasing ability to adapt gameplay to game conditions. Conclusions: While sport education has the capacity to develop competent players, different levels of teacher guidance and learners’ instructional responsibility are necessary when teaching tactics.     

Is passive drag dependent on the interaction of kayak design and paddler weight in flat-water kayaking?

Abstract

Drag is one of the major factors that influences kayaking performance. To focus on the drag of the kayak’s hull shape and the paddlers’ weight per se, the passive drag (D_p) was measured on a flat-water sprint course for one paddler with added weights. D_p was measured by an electromechanical towing device using a load cell, at incremental and constant velocities from 2.78 to 5.56 m/s. Three kayaks of different sizes and shapes (Nelo® K1 Quattro-M, ML, and L) were used and the paddlers’ body weight was adjusted with weights so the total paddler weight in the kayak was 65, 75, and 85 kg. The mean D_p increased by the power function of D = kvⁿ (mean R² = .990; SD .006). The D_p went from 21.37?±?1.29 N at 2.78 m/s to 89.32?±?6.43 N at 5.56 m/s. For the two lighter weighted kayaks (65 and 75 kg), the lowest D_p was observed with different kayak sizes (M, ML, or L) depending on the target velocity. The manufacturers suggest that paddlers should select a kayak size according to their body weight to minimise drag; however, the results of this study suggest that target velocities, and thus competition distance should also be factored into kayak selection.     

Engaging students in learning: findings from a study of project-led education

This paper reports on findings from a three-year study of project-based learning implemented in the first year of the Industrial Engineering and Management programme, at the University of Minho, Portugal. This particular model was inspired on project-led education (PLE), following Powell and Weenk's [2003. Project-Led Engineering Education. Utrecht: Lemma] work. It aims to analyse students’ perceptions of PLE as a learning device and its implications for faculty and students’ role in teaching and learning. Data collection took place in two phases through individual surveys and focus groups to students. Findings suggest the importance of PLE as a device to enhance meaningful learning and provide evidence from students that it helps to increase their engagement in learning. Implications of PLE for faculty and students role in teaching and learning will be discussed in the paper.     

Effects of plyometric jump training in female soccer player’s vertical jump height: A systematic review with meta-analysis

ABSTRACT

To assess the effects of plyometric jump training (PJT) in female soccer player’s vertical jump height, a review was conducted using the data sources PubMed, MEDLINE, Web Of Science and SCOPUS. Only peer-review articles were included. To qualify for inclusion in the meta-analysis, studies must have included (i) a PJT programme of at least 2 weeks, (ii) cohorts of healthy female soccer players with no restriction for age, (iii) a control group, (iv) a measure of countermovement jump (CMJ). The inverse variance random-effects model for meta-analyses was used. From 7,136 records initially identified through database searching, 8 were eligible for meta-analysis, comprising 9 training groups (n = 99) and 9 control groups (n = 94). The magnitude of the main effect was moderate (ES = 1.01 [95%CI = 0.36–1.66], Z = 3.04, p = 0.002). Sub-group analyses were performed (i.e., PJT frequency, duration and total number of sessions), revealing no significant subgroup differences (p = 0.34–0.96). Among the studies included in this review, none reported injury or other adverse effects. In conclusion, PJT is effective in female soccer players for the improvement of vertical jump height. In future, research must identify specific dose–response relationships following PJT, particularly in the long term.