The influence of match phase and field position on collective team behaviour in Australian Rules football

This study investigated the influence of match phase and field position on collective team behaviour in Australian Rules football (AF). Data from professional male athletes (years 24.4 ± 3.7; cm 185.9 ± 7.1; kg 85.4 ± 7.1), were collected via 10 Hz global positioning system (GPS) during a competitive AFL match. Five spatiotemporal metrics (x-axis centroid, y–axis centroid, length, width, and surface area), occupancy maps, and Shannon Entropy (ShannEn) were analysed by match phase (offensive, defensive, and contested) and field position (defensive 50, defensive midfield, forward midfield, and forward 50). A multivariate analysis of variance (MANOVA) revealed that field position had a greater influence on the x-axis centroid comparative to match phase. Conversely, match phase had a greater influence on length, width, and surface area comparative to field position. Occupancy maps revealed that players repositioned behind centre when the ball was in their defensive half and moved forward of centre when the ball was in their forward half. Shannon Entropy revealed that player movement was more variable during offence and defence (ShannEn = 0.82–0.93) compared to contest (ShannEn = 0.68–0.79). Spatiotemporal metrics, occupancy maps, and Shannon Entropy may assist in understanding the game style of AF teams.     

Metabolic time-course response after resistance exercise: A metabolomics approach

This study analysed the time course of the global metabolic acute response after resistance exercise (RE), with the use of proton nuclear magnetic resonance (¹H NMR) spectroscopy. Ten young healthy males performed 4 sets of 10 repetitions at 70% of one-repetition maximum in the leg press and knee extension exercises and had the serum metabolome assessed at 5, 15, 30 and 60 min post-RE. Measurements were also performed 1 h earlier and immediately before the exercises, as an attempt to characterise each participant’s serum metabolome at rest. One-way ANOVA was applied and the significance level was set at P ≤ 0.05. RE promoted an increase in 2-hydroxybutyrate, 2-oxoisocaproate, 3-hydroxyisobutyrate, alanine, hypoxanthine, lactate, pyruvate and succinate concentrations. However, isoleucine, leucine, lysine, ornithine and valine had their concentrations decreased post-RE compared with at rest. This is the first study to show significant changes in serum concentration of metabolites such as 2-oxoisocaproate, 2-hydroxybutyrate, 3-hydroxyisobutyrate, lysine, hypoxanthine and pyruvate post-RE, attesting metabolomics as an interesting approach to advance in the understanding of global RE-induced metabolic changes. Moreover, the present data could influence the time point of blood collection in the future studies that aims to investigate metabolism and exercise.     

Friendship similarities in internalizing problems in early childhood

A key factor identified in friendship formation and stability is similarity. Homophily of externalizing problems has been reported frequently, but less attention has been directed at homophily of internalizing problems. Whether young children who are friends resemble each other in their internalizing problems is thus largely unknown. In order to increase understanding of the social risk factors implicated in the etiology of internalizing problems, it is important to establish whether internalizing problems cluster in friendships. The present study examines homophily of internalizing problems while controlling for externalizing problems in a sample of children aged 4–8.     

Collective team behaviour of Australian Rules football during phases of match play

Using the spatiotemporal characteristics of players, the primary aim of this study was to determine whether differences in collective team behaviour exist in Australian Rules football during different phases of match play. The secondary aim was to determine the extent to which collective team behaviour differed between competing teams and match half. Data was collected via 10 Hz global positioning system devices from a professional club during a 2 × 20 min, 15-v-15-match simulation drill. Five spatiotemporal variables from each team (x centroid, y centroid, length, width, and surface area) were collected and analysed during offensive, defensive, and contested phases. A multivariate analysis of variance comparing phase of match play (offensive, defensive, contested), Team (A & B), and Half (1 & 2) revealed that x-axis centroid and y-axis centroid showed considerable variation during all phases of match play. Length, width, and surface area were typically greater during the offensive phase comparative to defensive and contested phases. Clear differences were observed between teams with large differences recorded for length, width, and surface area during all phases of match play. Spatiotemporal variables that describe collective team behaviour may be used to understand team tactics and styles of play.     

Demonstration of pelvic anatomy by modified midline transection that maintains intact internal pelvic organs

Gross dissection for demonstrating anatomy of the human pelvis has traditionally involved one of two approaches, each with advantages and disadvantages. Classic hemisection in the median plane through the pelvic ring transects the visceral organs but maintains two symmetric pelvic halves. An alternative paramedial transection compromises one side of the bony pelvis but leaves the internal organs intact. The authors propose a modified technique that combines advantages of both classical dissections. This novel approach involves dividing the pubic symphysis and sacrum in the median plane after shifting all internal organs to one side. The hemipelvis without internal organs is immediately available for further dissection of the lower limb. The hemipelvis with intact internal organs is ideal for showing the complex spatial relationships of the pelvic organs and vessels relative to the intact pelvic floor. Anat Sci Educ 3:254–260, 2010. © 2010 American Association of Anatomists.     

‘Singled out because of skin color … ’: exploring ethnic minority female teachers’ embodiment in physical education

There is a significant lack of diversity within the teaching population nationwide that reflects historical, political, and institutional racialized inequality. In the context of physical education, ethnic minority teachers often report feeling ‘different,’ marginalized, and struggle to negotiate the dominant school culture they feel they do not belong to. Purpose: To explore how race and gender intersect in the lived experiences of ethnic minority female PE teachers in predominantly white schools in the United States. Methods: This study used narrative and visual research methods. Results: Participants often felt isolated and uncomfortable in their educational contexts, actively seeking out other ethnic minorities to make meaningful connections and validate their lived experiences. Discussion: The intersection of race and gender in participants’ embodied identities reflects sexist and racist systems in which white privilege is positioned as normal or universal. PE and PE teacher education programs must actively work to disrupt and destabilize these norms.     

Linkages between children's and their friends' social and physical aggression: evidence for a gene-environment interaction?

Based on a sample of 406 seven-year-old twins, this study examined whether exposure to friends' social or physical aggression, respectively, moderates the effect of heritability on children's own social and physical aggression. Univariate analyses showed that children's own social and physical aggression were significantly explained by genetic factors, whereas friends' social and physical aggression represented "true" environmental factors that were unrelated to children's genetic dispositions. Multivariate analyses further suggested a possible gene-environment interaction in the link between friends' and children's physical aggression but not in the link between friends' and children's social aggression. Instead, friends' social aggression was directly related to children's social aggression, in addition to genetic effects on this behavior. Theoretical and practical implications of these results are discussed.     

Examining genetic and environmental effects on social aggression: a study of 6-year-old twins

Using a genetic design of 234 six-year-old twins, this study examined (a) the contribution of genes and environment to social versus physical aggression, and (b) whether the correlation between social and physical aggression can be explained by similar genetic or environmental factors or by a directional link between the phenotypes. For social aggression, substantial (shared and unique) environmental effects but only weak genetic effects were found. For physical aggression, significant effects of genes and unique environment were found. Bivariate modeling suggests that social and physical aggression share most of their underlying genes but only very few overlapping environmental factors. The correlation between the two phenotypes can also be explained by a directional effect from physical to social aggression.     

Self-concept in children receiving special support at school

The aim of this study is to investigate the variations of self-concept in pupils attending basic compulsory schools and special units. It also examines self-concept in pupils receiving support according to different models. The study involved 183 pupils aged nine to 13 years, attending basic compulsory schools or special programme units in Sweden. Seventy-seven pupils were receiving support from special educators, who have completed a supplementary programme in special education. A comparison was made between pupils receiving support and pupils receiving no support and between pupils in different organization models of support. Global self-concept at school does not seem to be related to the model of special support. Pupils at compulsory schools who are receiving support differ from pupils who receive no support, in that peer relations appear to be more important for their self-concept at school. This could be interpreted as being a compensatory strategy to maintain a good self-concept in spite of difficulties at school. Some implications for educational strategies are discussed.