Sport selection in under-17 male roller hockey

Abstract

Characteristics of 32 international and 41 local under-17 (U-17) (14.5–16.5 years) roller hockey players were considered in the context of discrimination by competitive level using training history, anthropometry, skeletal maturation, and several laboratory and field performance tests. More international (42%) than local (22%) players were advanced in maturity status. International players had slightly less hockey experience (years), but had more practice sessions and match time (minutes) during the season. Local players were shorter and attained better performance in the 25-m dash, while international players performed better in sit-ups, ball throw and 20-m shuttle run. The fatigue index derived from the Wingate anaerobic test was higher among local players, while peak torques of knee extension and flexion were greater in international players. Stepwise discriminant function correctly classified 85% of players by competitive level based on grip strength, ratio of eccentric and concentric knee extension, number of training sessions, playing time and fatigue index. The results suggested an interaction among strength, anaerobic fitness and training plus game time as factors in discriminating international from local level players and by inference in the selection and development of youth roller hockey players.     

Mechanical properties of the triceps surae: Differences between football and non-football players

Abstract

We investigated the mechanical properties of the triceps surae between professional, junior, and non-football players. Fifty-nine men participated in this study. The mechanical properties of the right legs’ triceps surae were measured in vivo using a free oscillation technique; no significant differences existed between the groups. The mean results for musculo-articular stiffness, damping coefficient, and damping ratio were as follows: professional football players (21523 N· m^?1, 330.8 N · s · m^?1, and 0.201); junior football players (21063 N · m^?1, 274.4 N · s · m^?1, and 0.173); and non-players (19457 N · m^?1, 281.5 N · s · m^?1, and 0.184). When analysed according to position, the results were as follows: defender (21447 N · m^?1, 308.6 N · s · m^?1, and 0.189); midfielder (20762 N · m^?1, 250.7 N · s · m^?1, and 0.157); winger (21322 N · m^?1, 335.1 N · s · m^?1, and 0.212); forward (22085 N · m^?1, 416.2 N · s · m^?1, and 0.254); and non-players (19457 N · m^?1, 281.5 N · s · m^?1, and 0.184).

Thus, football training, football games, and the position played had no effect on triceps surae mechanical properties. These results may be attributed to opposing adaptations between different types of training that are usually implemented in football. Alternatively, the minimum strain amplitude and/or frequency threshold of the triceps surae required to trigger adaptations of mechanical properties might not be achieved by football players with football training and matches.     

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.     

Premarital Sex, Social Support, Submissive Behaviors, and Loneliness Among Turkish University Students

The purpose of this study was to investigate whether differences in social support, submissive behaviors, and loneliness existed among Turkish university students who had had premarital sexual intercourse and those who had not. Using self-reported questionnaires, students who had experienced sexual intercourse were contrasted with those who had not. Data were gathered on 420 university students in Ankara, Turkey. MANOVA statistics were used in the data analysis. Results indicated that more than 75?% of the total respondents reported that they had never had sexual intercourse; the frequency of sexual intercourse was higher among males than females. It was found that students who had had sexual intercourse reported less perceived support from family. The two groups were not significantly different, however, in perceived support from friends, submissive behaviors and loneliness. Possible interpretations of these data and implications for future study are suggested.     

Disclosing biology teachers’ beliefs about biotechnology and biotechnology education

Teachers have been shown to frequently avoid addressing biotechnology topics. Aiming to understand the extent to which teachers’ scarce engagement in biotechnology teaching is influenced by their beliefs and/or by extrinsic constraints, such as practical limitations, this study evaluates biology teachers’ beliefs about biotechnology and biotechnology teaching. The findings of a survey administered to 93 secondary school teachers reveal that, in spite of holding positive beliefs about biotechnology, teachers overestimate the obstacles presented at biotechnology teaching, particularly concerning material and resource limitations. Implications of these findings for teacher training program design are discussed.     

How users search and what they search for in the medical domain

The internet is an important source of medical knowledge for everyone, from laypeople to medical professionals. We investigate how these two extremes, in terms of user groups, have distinct needs and exhibit significantly different search behaviour. We make use of query logs in order to study various aspects of these two kinds of users. The logs from America Online, Health on the Net, Turning Research Into Practice and American Roentgen Ray Society (ARRS) GoldMiner were divided into three sets: (1) laypeople, (2) medical professionals (such as physicians or nurses) searching for health content and (3) users not seeking health advice. Several analyses are made focusing on discovering how users search and what they are most interested in. One possible outcome of our analysis is a classifier to infer user expertise, which was built. We show the results and analyse the feature set used to infer expertise. We conclude that medical experts are more persistent, interacting more with the search engine. Also, our study reveals that, conversely to what is stated in much of the literature, the main focus of users, both laypeople and professionals, is on disease rather than symptoms. The results of this article, especially through the classifier built, could be used to detect specific user groups and then adapt search results to the user group.     

International approaches to the definition,philosophical tenets,and core elements of physical literacy: A scoping review

PROSPECTS - This paper addresses the inadequate understanding of the concept of physical literacy (PL), often originating from complex terminology and philosophical language used in the current...     

Profiles of learning opportunities of multilingual and monolingual children in kindergarten

Early childhood education serves an increasing number of multilingual children, and teachers are challenged to create high-quality learning opportunities in the classroom for all children. The child’s engagement and interactions with the teacher are important in this respect. The present study therefore examined how multilingualism relates to engagement and teacher-child interactions, taking a person-oriented approach. During one school year, 76 kindergarteners (43 multilingual) from 19 classrooms were observed for behavioral engagement and individual teacher-child interactions. Five engagement profiles were identified that reflect different levels of engagement across classroom settings. Multilingual children were overrepresented in profiles that showed lower engagement in one or more settings. Also, five interaction profiles were identified that showed strong diversity in the interactions of teachers with children in their classroom. Monolingual and multilingual children were equally represented across these profiles. Children in the more beneficial interaction profiles were also often in the moderate-to-high engagement profiles.