Magnesium status and the physical performance of volleyball players: effects of magnesium supplementation

Abstract

The aim of this study was to test the hypothesis that magnesium supplementation influences the physical performance of volleyball players, as the efficacy of this approach remains questionable. Twenty-five professional male volleyball players were assigned randomly to experimental (350 mg Mg · d^–1, 4 weeks) and control groups (500 mg maltodextrin · d^–1, 4 weeks) maintaining inter-group homogeneity of urinary magnesium. Erythrocyte, plasma and urinary magnesium levels, plasma creatine kinase activity, lactate production, maximal oxygen uptake (VO₂ max) and plyometric (squat jump, countermovement jump, countermovement jump with arm swing) and isokinetic (peak torque, potency and total work) performances were evaluated before (T₀) and after (T₁) supplementation. Levels of erythrocyte and urinary magnesium and creatine kinase activity and VO₂ max remained within normal ranges in both groups. Plasma magnesium decreased significantly only within the experimental group. Significant decreases in lactate production and significant increases (of up to 3 cm) in countermovement jump and countermovement jump with arm swing values were detected in the experimental group following magnesium supplementation, but not in the control group at T₁. It is concluded that magnesium supplementation improved alactic anaerobic metabolism, even though the players were not magnesium-deficient.     

Isokinetic hamstrings-to-quadriceps peak torque ratio: the influence of sport modality, gender, and angular velocity

The purpose of this study was to determine differences in hamstrings-to-quadriceps (H/Q) peak torque ratios evaluated at different angular velocities between men and women who participate in judo, handball or soccer. A total of 166 athletes, including 58 judokas (26 females and 32 males), 39 handball players (22 females and 17 males), and 69 soccer players (17 females and 52 males), were evaluated using an isokinetic dynamometer. The H/Q isokinetic peak torque ratios were calculated at angular velocities of 1.05 rad · s?1 and 5.23 rad · s?1. In the analysis by gender, female soccer players produced lower H/Q peak torque ratios at 1.05 rad · s?1 than males involved in the same sport. However, when H/Q peak torque ratio was assessed at 5.23 rad · s?1, there were no significant differences between the sexes. In the analysis by sport, there were no differences among females at 1.05 rad · s?1. In contrast, male soccer players had significantly higher H/Q peak torque ratios than judokas (66 ± 12% vs. 57 ± 14%, respectively). Female handball players produced significantly lower peak torque ratios at 5.23 rad · s?1 than judokas or soccer players, whereas males presented no ratio differences among sports At 5.23 rad · s?1. In the analysis by velocity, women's muscular ratios assessed at 1.05 rad · s?1 were significantly lower than at 5.23 rad · s?1 for all sports; among men, only judokas presented lower ratios at 1.05 rad · s?1 than at 5.23 rad · s?1. The present results suggest that sport modality and angular velocity influence the isokinetic strength profiles of men and women.     

Exploring the present and projecting the future: people with severe mental illness speaking for themselves

The participation of people with mental illness in research is key to their empowerment and provides them with a highly meaningful experience. The aim of this article was to explore the perspectives, views and experiences of people with severe mental illness (SMI) regarding their present life and projection of the future (desires, expectations related to the illness, their personal, working, relational life, etc.). We present the results of a qualitative study in which two personal interviews were conducted with seven people with SMI, incorporating visual elements produced by the participants themselves (photographs and drawings). The results obtained allow us to take a more in-depth look at these people’s reflections with regard to the present and future, while also opening a working path for professionals in the social education services.     

The Bologna Process and Lifelong Education: Problem‐Based Learning

This article describes the application of Problem‐Based Learning (PBL) methodology in the context of a student congress, arguing that such new approaches to learning are best‐suited to the goals of the Bologna Process. The Congress in question enabled Spanish graduate students in Psychology, many of them mid‐career professionals, to increase their learning motivation, delve deeper into the learning experience, and further apply their learning and research. By taking an interdisciplinary approach, all the teachers concerned were able to coordinate their involvement. Feedback received from students and professors confirms that the Congress promoted new strategies and skills including self‐directed learning.     

Creating a common grammar for European higher education governance

This paper addresses the interaction between European Union policies and national higher education sectors in the countries involved in the TRUE project (England, France, Germany, Italy, The Netherlands, Norway, Portugal and Switzerland) making the case for European governance. Relevant for this matter is the role of political processes that evolve at European level shaping political discourses and practices, thus creating a common grammar for European higher education governance. By empirically focusing on evaluation and funding policies the paper argues that European governance reflects in how this common grammar is being created and reconfiguring the environment within which European higher education systems and institutions are developing.     

Neuroanatomy education: The impact on perceptions,attitudes, and knowledge of an intensive course on general practice residents

General practitioners are responsible for the management of an increasing number of patients with neurological illness, and thus a solid education in neurosciences is a necessary component of their training. This study examines the effects of an intensive clinical neuroanatomy course on twenty general practice residents’ perceptions, attitudes, and knowledge. A knowledge test was completed by the participants and by a control group at four different time points. The participants were asked to answer a questionnaire about their reasons for signing up for the course and their attitudes and perceptions toward the course experience. Experimental and control groups demonstrated identical mean baseline test scores. The experimental group significantly increased its test scores (plus 49.0% correct answers, a mean improvement of 120%) relative to controls after the educational intervention. There were no differences among scores from the evaluated time points after the educational intervention in the experimental group. In the control group, there were likewise no significant differences between the four evaluated time points. Most participants indicated that they signed up for the course to update/acquire knowledge and skills in the field of neurosciences, and also because they had difficulty in diagnosing and managing patients with neurological diseases. Participants’ attitudes and perceptions toward the course experience were very positive. Most of the participants (n = 17; 85%) rated the course as “extremely useful,” and 3 (15%) rated it as “very useful.” This study provides evidence demonstrating the potential positive effect of neurosciences education to general practice residents. Anat Sci Educ 10: 465–474. © 2017 American Association of Anatomists.     

What is the students’ interest in biology after the biology curriculum modification?

Decreasing interest in Science among students, confirmed by several investigations, calls for the need to revise the contents of the curricula for Science subjects, including Biology. Modern Biology curricula should not only contain key biological concepts but also provide a teacher with sufficient space to develop students’ competencies of scientific work and positive attitudes to Science. When preparing the curriculum, it is necessary to consider also students’ interest in selected curriculum topics and their benefit for everyday life. The objective of our research was to identify whether the performed transformation of the Biology curriculum for elementary schools increased the students’ interest in Biology and the contents thereof. We were also investigating students’ preferences in their interest in Biology topics and their interest in selected teaching methods and approaches. Our research confirmed the positive interest in Biology among majority of students who prefer direct, active participation in the process of knowledge acquisition through the study and exploration of living organisms as well as by the execution and assessment of practicals and experiments.     

ICT and Older People: Beyond Usability

This study examined the use that older, regular users of computers make of information and computer technology in their daily lives. Opinions from such users were obtained regarding what they want these technologies to offer them in the future. By means of a discussion group and an online questionnaire, our critical case examined a group of mature senior students from the Universitat Oberta de Catalunya (online learning) who have used computers and the Internet in their activities. In general, the participants needed to know the function of the tool beforehand and to have continued support and confidence. In particular, they need the certainty that the future technology will allow them to maintain their independence and autonomy. Older people's adoption of IT needs to be treated as more than merely a question of usability. Attitudes, experience of use, and perceived benefits are also key aspects that must be taken into account.     

Analysis of a load application point in spline coupling teeth

The objective of this paper is to investigate the position of the resultant force in involute spline coupling teeth due to the contact pressure distribution for both ideal and misaligned conditions. In general, spline coupling teeth are in contact all along the involute profile and the load is far from uniform along the contact line. Theoretical models available in publications consider the resultant contact force as it is applied at the pitch diameter, and this study aims to evaluate the error introduced within the confines of a common approximation environment. This analysis is carried out through using finite element method （FEM） models, considering spline couplings in both ideal and misaligned conditions. Results show that the differences between the load application diameter and pitch diameter are not very obvious in both ideal and misaligned conditions; however, this ap- proximation becomes more important for the calculation of the tooth stiffness.