Effects of plyometric training on maximal-intensity exercise and endurance in male and female soccer players

In a randomised controlled trial design, effects of 6 weeks of plyometric training on maximal-intensity exercise and endurance performance were compared in male and female soccer players. Young (age 21.1 ± 2.7 years) players with similar training load and competitive background were assigned to training (women, n = 19; men, n = 21) and control (women, n = 19; men, n = 21) groups. Players were evaluated for lower- and upper-body maximal-intensity exercise, 30 m sprint, change of direction speed and endurance performance before and after 6 weeks of training. After intervention, the control groups did not change, whereas both training groups improved jumps (effect size (ES) = 0.35–1.76), throwing (ES = 0.62–0.78), sprint (ES = 0.86–1.44), change of direction speed (ES = 0.46–0.85) and endurance performance (ES = 0.42–0.62). There were no differences in performance improvements between the plyometric training groups. Both plyometric groups improved more in all performance tests than the controls. The results suggest that adaptations to plyometric training do not differ between men and women.     

An analysis of the sources of earnings variation among Brazilian males

The paper uses data from the 1980 Brazilian census to analyse the sources of earnings variation among males with emphasis on the role of education, labor market segmentation, geographic location and sector of economic activity. The results indicate a sizeable private rate of return to investment in education across labor market “segments”, especially among rural workers and the self-employed. Such a finding is upheld after econometric corrections for dependent variable (earnings) truncation and selectivity bias regarding who enters a particular economic sector. However, regional earnings differentials persist even after adjustment for a set of personal and job characteristics. Thus, internal migration still has a role to play towards reducing regional earnings disparities.     

Lifelong learning policies shaping the life courses of young adults. An interpretative analysis of orientations,objectives and solutions

ABSTRACT

In the following article, we share our findings from the comparative analyses of 54 lifelong learning policy measures implemented in nine European countries, with a particular focus on their orientations, objectives, and solutions devised. Informed by the theoretical framework of Interpretive Policy Analysis (IPA), we have further reasoned on the impacts and unintended effects on young adults’ life course transitions, especially those in vulnerable positions, as well as on the hidden ambivalences and incompatibilities in the objectives and orientations of lifelong learning policies. The article provides, first, a brief discussion of the conceptual and methodological choices made. Second, it gives an overview of the design and data basis of our research. In the third section, we present and discuss the central findings from our interpretive analyses, and we finally conclude with a discussion on current trends in lifelong learning policymaking and on their impact on young adults’ transitions.     

Teaching and learning about solid waste: aspects of content knowledge

This paper investigates aspects of content knowledge related to teaching and learning about solid waste, focusing on the processes of learning and teaching by Elementary School teachers in Brazil, in two modalities of continuing education: courses and school‐based meetings. We analyse elements of teachers' reflections whilst referring to three dimensions of environmental education: knowledge, values (ethic and aesthetic), and political participation. We identify which dimensions are predominant, or absent, and the aspects included and developed in projects elaborated by teachers. The results raise issues we consider important to support teacher education and curriculum programmes and help teachers develop more substantial, critical and effective projects about the subject.     

A student's construction of transformations of functions in a multiple representational environment

This paper reports on a case study of a 16-year-old student working on transformations of functions in a computer-based, multi-representational environment. The didactic approach to reflections, translations and stretches began with visualization exercises, and then was extended to investigate the implications of visual changes in data points, and subsequently, in algebraic symbolism. A detailed analysis of the student's work during the transition from the use of visualization and analysis of discrete points to the use of algebraic symbolism is presented. Two new semiotic forms are introduced as an alternative kind of algebraic symbolism and as a means to facilitate the transition to f(x) notation: covariational equations and the horseshoe display for transformations. The implications of this case for the redesign and modification of the software are discussed.     

Tutoring through the internet: how students and teachers interact to construct meaning

Two episodes of tutoring through the internet have been analysed in terms of situational, interactive and content perspectives. The episodes involved secondary students who submitted queries about chemistry issues to an online service provided by teachers. Studies of the asking of questions and of the dynamics of classroom interactions are employed to discuss the interactive and content factors of this approach to teaching–learning. The functions conveyed by students’ and teachers’ utterances are used to identify the structural patterns of the interactions. The occurrence of classical and inverted I–R–F exchanges, the questioner’s role, the continuity of the dialogues, and other structural patterns, are used to classify the episodes as being Debate and Triadic Dialogue. The notions of mastering cultural tools and scaffolding are used to account for how meaning is constructed through the interactions.     

Making Migration Work

Schools the world over are being transformed by growing numbers of immigrant-origin children. As schools face the challenge of educating linguistically, culturally, and racially diverse students, globalization imposes yet another set of demands on education. In this article we examine the varied pathways taken by immigrant-origin children. We outline some of the most critical contributors shaping their transition to new countries with a specific focus on education and schooling and explore some promising practices in a variety of national contexts and domains of immigrant life.     

Young People's Images of Old Age in Chile: Exploratory Research

According to gerontological thought, an important part of senior citizens' disabilities are products of their social exclusion rather than factors associated with their physical or mental health. How these exclusions come about was the purpose of the research reported in this article. The study was conducted among 682 Chilean university students using a semantic differential test. A generalized negative image on old age was observed. The conclusion is that social images of old age affect the well-being of present and future senior citizens.     

Interferential therapy effect on mechanical pain threshold and isometric torque after delayed onset muscle soreness induction in human hamstrings

Abstract

This study was undertaken to examine the acute effect of interferential current on mechanical pain threshold and isometric peak torque after delayed onset muscle soreness induction in human hamstrings. Forty-one physically active healthy male volunteers aged 18?33 years were randomly assigned to one of two experimental groups: interferential current group (n = 21) or placebo group (n = 20). Both groups performed a bout of 100 isokinetic eccentric maximal voluntary contractions (10 sets of 10 repetitions) at an angular velocity of 1.05 rad · s^?1 (60° · s^?1) to induce muscle soreness. On the next day, volunteers received either an interferential current or a placebo application. Treatment was applied for 30 minutes (4 kHz frequency; 125 μs pulse duration; 80?150 Hz bursts). Mechanical pain threshold and isometric peak torque were measured at four different time intervals: prior to induction of muscle soreness, immediately following muscle soreness induction, on the next day after muscle soreness induction, and immediately after the interferential current and placebo application. Both groups showed a reduction in isometric torque (P < 0.001) and pain threshold (P < 0.001) after the eccentric exercise. After treatment, only the interferential current group showed a significant increase in pain threshold (P = 0.002) with no changes in isometric torque. The results indicate that interferential current was effective in increasing hamstrings mechanical pain threshold after eccentric exercise, with no effect on isometric peak torque after treatment.