School experience,relational justice and legitimation of institutional

This study analysis the relationship between perceptions of the justice of teacher’ behaviour and (a) the legitimation of school authority and (b) the legitimation of institutional authorities outside school. 448 adolescent students participated in the study. In questionnaire participants were asked about (a) perceptions of the justice of teachers’ behaviour; (b) evaluation of the school experience; and (c) evaluation of institutional authorities. Results show that the evaluation of the justice of teacher behaviour, in particular relational and procedural justice, have an impact on the legitimation of the authority of teachers and on the evaluation of institutional authorities outside school. Results also show that the legitimacy granted to teachers is a mediator variable between perceptions of justice in school and evaluation of authorities outside school. These results are discussed in the context of the studies on the relationship between school experience and adolescents attitudes towards authorities, and in the framework of the “Relational Model of Authority” and of the “Group Value Model”.     

A scale-based approach to interdisciplinary research and expertise in sports

After more than 20 years since the introduction of ecological and dynamical approaches in sports research, their promising opportunity for interdisciplinary research has not been fulfilled yet. The complexity of the research process and the theoretical and empirical difficulties associated with an integrated ecological-dynamical approach have been the major factors hindering the generalisation of interdisciplinary projects in sports sciences. To facilitate this generalisation, we integrate the major concepts from the ecological and dynamical approaches to study behaviour as a multi-scale process. Our integration gravitates around the distinction between functional (ecological) and execution (organic) scales, and their reciprocal intra- and inter-scale constraints. We propose an (epistemological) scale-based definition of constraints that accounts for the concept of synergies as emergent coordinative structures. To illustrate how we can operationalise the notion of multi-scale synergies we use an interdisciplinary model of locomotor pointing. To conclude, we show the value of this approach for interdisciplinary research in sport sciences, as we discuss two examples of task-specific dimensionality reduction techniques in the context of an ongoing project that aims to unveil the determinants of expertise in basketball free throw shooting. These techniques provide relevant empirical evidence to help bootstrap the challenging modelling efforts required in sport sciences.     

The role of preparatory heart rate deceleration on balance beam performance

Preparatory heart rate deceleration occurs in tasks with an external focus of attention and is often assumed to facilitate balance performance. However, its effects upon sport-related complex balance movements have not been studied. Heart rate patterns during the preparation period of an acrobatic element (flic-flac) on the balance beam were studied in 14 female gymnasts (M age 13.2 years). A significant heart rate deceleration was found in attempts with a fall in the consecutive acrobatic element, but not in attempts without a fall. These data suggest that preparatory heart rate deceleration may be detrimental to the performance of complex movements on the balance beam.     

Effects of AM3 (Inmunoferon) on increased serum concentrations of interleukin-6 and tumour necrosis factor receptors I and II in cyclists

The aims of this study were to examine the changes in plasma concentrations of inflammatory cytokines induced by training and competition in professional cyclists. We report the serum concentrations of interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-a), tumour necrosis factor receptors I and II (TNFR-I and -II) in a prospective, randomized, double-blind trial involving the administration of AM3 (Inmunoferon), an oral booster immunomodulator, or placebo to 16 professional cyclists (n = 8 in each group) for 65 consecutive days. Serum was collected just before treatment began (baseline), at the end of pre-competition training, before the mountain stage of the competition (60 days), 4 h after finishing this stage (62 days), and 18 h after the fifth and last day of competition (65 days). To determine the normal levels of cytokines and soluble TNF receptors, individual samples from 14 moderately trained healthy controls were studied. After 60 days of training, the serum concentrations of IL-6 did not differ significantly from those at the beginning of the study for either group of cyclists (placebo and AM3). A significant rise was seen in IL-6 concentrations in both the AM3 and placebo groups at 62 days, 4 h after finishing the mountain stage. The increase was significantly greater in the placebo group than in the AM3 group. At 65 days of treatment, 18 h after the fifth and last day of competition, IL-6 concentrations were similar to those recorded at the end of the training, but were significantly higher in the placebo group than in the AM3 group. At the end of training, serum TNFR-I concentrations in both groups of cyclists were significantly lower than at baseline. The concentrations of serum TNFR-I and -II both 4 h after finishing the mountain stage and 18 h after the fifth and last day of competition were significantly higher than those recorded after training in both groups. Professional cycling competition is associated with increases in serum IL-6 and TNFR-I and -II concentrations. Inmunoferon treatment reduced significantly the concentrations of IL-6 but not those of TNFR-I and -II.     

Association of different types of playing surfaces with bone mass in growing girls

The aim of this cross-sectional study was to compare bone mass in young female athletes playing ball games on different types of playing surfaces. About 120 girls, 9–13 years of age (10.6 ± 1.5 years old Tanner I–III) were recruited and divided into prepubertal and pubertal groups. The sample represented 3 groups of athletes: soccer (N = 40), basketball (N = 40), and handball (N = 40); and 6 different playing surfaces (soccer – ground, soccer – artificial turf, basketball – synthetic, basketball – parquet, handball – synthetic, and handball – smooth concrete). Total and regional body composition (bone mass, fat mass, and lean mass) were measured by dual-energy X-ray absorptiometry (DXA). The mechanical properties of the surfaces (force reduction, vertical deformation, and energy return) were measured with the Advanced Artificial Athlete (Triple A) method. The degree of sexual development was determined using Tanner test. The pubertal group showed that soccer players on the ground, basketball players on synthetic, and handball players on smooth concrete had higher values of bone mineral content (BMC) and bone mineral density (BMD) (P < 0.05) than the soccer players on the artificial turf, basketball players on parquet, and handball players on synthetic. In conclusion, a hard playing surface, with less vertical deformation and force reduction, and greater energy return, is associated with higher levels of BMD and BMC in growing girls, regardless of the sport they practice.     

Physical exercises for preventing injuries among adult male football players: A systematic review

Background:Football is the most practised sport in the world and is associated with the risk of injuries in the players.Some studies have been published that identify injury prevention programs,but there is no review of the full body of evidence on injury prevention programs for use by football coaches.The aim of this article was to carry out a systematic review of published studies on injury prevention programs for adult male footballers,identify points of common understanding and establish recommendations that should be considered in the design of injury prevention strategies.Methods:PubMed and EMBASE databases were used to identify relevant published articles using the following keywords:"soccer"AND"injury"AND"prevention".Results:A total of 2512 studies were identified initially,but only 11 studies met the inclusion criteria,and their outcomes are presented.Results revealed that injury prevention programs in football have focused on strength training,proprioceptive training,multicomponent programs(balance,core stability,and functional strength and mobility),and warm-up programs.Conclusion:Based on results from the studies analyzed,football players can lower the incidence of match and training injuries by participating in dynamic warm-up programs that include preventive exercises before games or during training sessions,and by adding strength,balance,and mobility training to the training sessions.     

Adherence to 24-hour movement guidelines among Portuguese preschool children: the prestyle study

ABSTRACT

Purpose

The 24-Hour Movement Guidelines (24 hMG) provide specific recommendations, including physical activity (PA), screen-time and sleep-duration, which preschoolers should achieve for a healthy day (24 h). The aim of the current study was to analyse preschooler’s adherence with the 24-Hour Movement Guidelines.     

Effectiveness during ball screens in elite basketball games

Ball screens are one of the most frequently used tactical behaviour in elite basketball games. The aim of the present study was to identify their predictors of success related to time, space, players, and tasks performed. The sample was composed of 818 ball screens corresponding to 20 close games (mean differences in score of 3.1 ± 0.8 points) randomly selected from the playoff games of the Spanish Basketball League (2008–2011). Classification tree analysis (CHAID) was used to analyse which variable or combination of variables, better predicts effectiveness during ball screens. The main results allowed identifying interactions with dribbler actions after the screen and the orientation of the screen on the ball. The results showed no interaction with game quarter and quarter minute temporal-related variables in both analyses. The present findings allow improving coaches’ strategic plans that involve selecting the most appropriate offensive approach when performing ball screens.     

Playing for freedom: Sócrates,futebol-arte and democratic struggle in Brazil

Brazilian futebol has provided the world with several first-class players who have left their footprint on football history. However, no player can be compared to Sócrates; Sócrates was not only an icon of futebol-arte who mastered the ‘back heel’ and played for the Brazilian team in two FIFA World Cups (1982 and 1986), he was also a political activist who fought for democracy from inside the football world and who joined the Brazilian struggle for civil liberties during the 1980s. Interviews with sport journalists, an exploration of my personal memories of Brazilian futebol and the political scene, and a revisiting of Sócrates’ chronicles and testimonies together demonstrate Sócrates’ belief that the futebol arena was a privileged place to fight for social change. Sócrates passed away in 2011, leaving an inspiring heritage of joy, futebol-arte and freedom struggle. His libertarian legacy must be acknowledged in a country where, despite being acclaimed as one of the most authentic cultural expressions of the people, futebol is controlled by a corrupted and authoritarian elite.     

Growth influences biomechanical profile of talented swimmers during the summer break

This study aimed to analyse the effect of growth during a summer break on biomechanical profile of talented swimmers. Twenty-five young swimmers (12 boys and 13 girls) undertook several anthropometric and biomechanical tests at the end of the 2011–2012 season (pre-test) and 10 weeks later at the beginning of the 2012–2013 season (post-test). Height, arm span, hand surface area, and foot surface area were collected as anthropometric parameters, while stroke frequency, stroke length, stroke index, propelling efficiency, active drag, and active drag coefficient were considered as biomechanical variables. The mean swimming velocity during an all-out 25 m front crawl effort was used as the performance outcome. After the 10-week break, the swimmers were taller with an increased arm span, hand, and foot areas. Increases in stroke length, stroke index, propelling efficiency, and performance were also observed. Conversely, the stroke frequency, active drag, and drag coefficient remained unchanged. When controlling the effect of growth, no significant variation was determined on the biomechanical variables. The performance presented high associations with biomechanical and anthropometric parameters at pre-test and post-test, respectively. The results show that young talented swimmers still present biomechanical improvements after a 10-week break, which are mainly explained by their normal growth.