While network analysis is a major methodological approach in many disciplines of the social and natural sciences, it has only recently come into the focus of sport researchers. This article assesses the utility of network analysis to analyze sport phenomena. We begin with an overview of social network analysis (SNA) and related concepts. To explore research topics and approaches, we conduct a systematic review of empirical literature of SNA and its application to sport. Based on this review, we provide a sixdimensional conceptual typology of SNA applications in sportcompetition networks, interaction networks, inter-organizational networks, intra-organizational networks, affiliation networks and social environments. Potential future directions for this promising approach in sport research are discussed. Social network analysis (SNA) is a combination of theory and methods in which relations take precedence over, or at least are on par with, the characteristics of actors engaged in them (

a b s t r a c tA novel metal-free electrocatalyst for the oxygen reduction reaction (ORR) is one of the most important issues in fuel cells. Here, we report a facile method to synthesize reduced graphene oxide (rGO) decorated with nitrogen-doped carbon nanowires (rGO-CN) as an electrocatalyst for ORR. After the polymerization of polpyrrole nanowires on the rGO surface (rGO-PPy), the carbonization of rGO-PPy at 800 C affords a unique nanostructured product by the integration of rGO sheets and the N-doped carbon nanowires with high nitrogen content. The morphology of rGO-CN is confirmed by TEM analysis and the chemical composition and interaction of the prepared samples are analyzed by XPS and FT-IR analysis. The electrocatalytic activity of rGO-CN toward ORR is also evaluated by the cyclic voltammetry. It is found that the rGO-CN electrode shows superior electrocatalytic performance toward ORR, compared to rGO and rGO-PPy, which demonstrates the promising potential of rGO-CN as a carbon-based, metal-free electrocatalyst for enhancing the electrocatalytic property towards ORR. ScienceDirect j o urn al h om epa ge: www.elsev ier.com/locate/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 4 0 ( 2 0 1 5 ) 6 8 2 7 e6 8 3 4 http://dx.

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Background Individual health behavior is related to environmental and social structures. To promote physical activity (PA) effectively, it is necessary to consider structural influences. Previous research has shown the relevance of the built environment. However, sex/gender differences have yet not been considered. The aim of this systematic review was to identify built environmental determinants of PA by taking sex/gender into account. Methods A systematic literature search was carried out using six electronic databases (PubMed, CINAHL, SportDiscus, PsycInfo, Scopus, Web of Knowledge) to identify studies analyzing the effect of changes in the built environment on PA, taking sex/gender into account. To be included, studies had to be based on quantitative data and a longitudinal study design. Changes in the built environment had to be objectively assessed. The methodological quality of the studies was examined using the QualSyst tool for examining risk of bias. Results In total, 36 studies published since 2000 were included in this review. The data synthesis revealed that the majority of reviewed studies found the built environment to be a determinant of PA behavior for both, males and females, in a similar way. Creating a new infrastructure for walking, cycling, and public transportation showed a positive effect on PA behavior. Findings were most consistent for the availability of public transport, which was positively associated with overall PA and walking. The improvement of walking and cycling infrastructure had no effect on the overall level of PA, but it attracted more users and had a positive effect on active transportation. In women, the availability of public transport, safe cycling lanes, housing density, and the distance to daily destinations proved to be more relevant with regard to their PA behavior. In men, street network characteristics and road environment, such as intersection connectivity, local road density, and the presence of dead-end roads, were more important determinants of PA. Conclusion This review sheds light on the relevance of the built environment on PA. By focusing on sex/gender differences, a new aspect was addressed that should be further analyzed in future research and considered by urban planners and other practitioners.

With digitalization and virtual entertainment being the megatrends of the 21st century, there is reasonable concern about the role of physical activity (PA) in the daily life of children and adolescents. To identify risk-groups with insufficient PA and to guide interventions, continuous and representative tracking of PA is crucial. In this paper, representative PA data of children and adolescents from the Motorik-Modul (MoMo) baseline study (2003–2006, N = 4,528) is compared to those of Wave 2 (2014–2017, N = 3,708). Participants aged 4–17 were drawn out of 167 sample points in Germany and the data was weighted to ensure representativeness for Germany. Organized (sports clubs and schools) and unorganized (unorganized sports and playing outside) PA was measured by questionnaire and stratified by sex, age, and socioeconomic status. Contrary to common expectation, overall PA remained stable among youths in the past ten years, however, there is an ongoing trend towards organized forms of PA at the expense of unorganized sports and playing outside. Besides different trends in settings, there is inequality in PA distribution among socioeconomic status and gender, unequally pronounced in different settings.

Background:Despite the popularity of football, the analysis of success factors in football remains a challenge. While reviews on performance indicators in football are available, none focuses solely on the identification of success factors and addresses the large and growing body of recent research up until 2016. Objective:To find out what determines success in football and to organize the body of literature, a systematic literature review analyzing existing studies with regard to success factors in football was undertaken. Methods:The studies included in this review had to deal with performance indicators related to success in football. The studies were published in 2016 or before. The initial search revealed 19,161 articles. Finally, sixty-eight articles were included in this review. The studies were clustered with regard to comparative analyses, predictive analyses and analyses of home advantage. Results:In total, 76 different variables were investigated in the reviewed papers. It appeared that the most significant variables are efficiency (number of goals divided by the number of shots), shots on goal, ball possession, pass accuracy/successful passes as well as the quality of opponent and match location. Moreover, new statistical methods were used to reveal interactions among these variables such as discriminant analysis, factor analysis and regression analysis. The studies showed methodological deficits such as clear operational definitions of investigated variables and small sample sizes. Conclusion:The review allows a comprehensive identification of critical success factors in football and sheds light on utilized methodological approaches. Future research should consider precise operational definitions of the investigated variables, adequate sample sizes and the involvement of situational variables as well as their interaction.

ObjectiveThe aim of this systematic review was to provide an overview of cross-sectional studies that examined health literacy among university students and to identify possible determinants related to health literacy.MethodThe current review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Three databases (PubMed, Scopus, and Web of Science) were systematically searched for cross-sectional studies that examined health literacy among university students. Results of included studies were narratively summarized.ResultsThe systematic review includes twenty-one research studies. The majority of studies report health literacy scores among university students that are lower compared to reference samples. The health literacy of students is influenced by different variables (age, gender, number of semesters, course of studies/curriculum, parental education, and socioeconomic background).DiscussionHealth literacy activities should target all students. Universities should make use of their resources and offer health literacy courses for students in which content is used from disciplines available at the university (e.g., medicine, health, or psychology). To increase effectiveness, health literacy courses should be adapted according to the different needs and characteristics of the student subgroups.

While adolescents and adults should limit high levels of sedentary behavior, university students spend large amounts of time on sedentary activities. The aim of this study was to investigate the effect of this prolonged sitting on students’ self-perceived physical, mental, and cognitive condition and to answer the question of whether simple standing breaks in lectures can help students improve these conditions and for example feel more concentrated, motivated, or less tense in class. A five-minute standing break was introduced using a designed presentation slide for one semester in five different 90-min lectures. In addition, an active break as well as an open break with no trigger were implemented in two further lectures to explicitly investigate the effects of a standing break. Before, during, and after the semester, the students were surveyed about their physical, mental, and cognitive condition (836 respondents at start, 634 during semester, and 528 at the end). To evaluate the practicality and acceptance of the standing break, lecturers were interviewed about their experience. At all survey time points, the standing break was highly accepted by the university students. About three quarters of the students felt a relaxation of the muscles in the neck and shoulder as well as in the back and the legs. More than three quarters perceived an increase in concentration, receptiveness and retentiveness, motivation, and well-being. Results of the statistical analysis indicate that a standing break as well as an active break are more effective than an open break to improve the self-perceived physical and psychological well-being of the university students. The increase in cognitive skills is reported by all groups, including the group who were offered open breaks. Hence, standing breaks in university lectures receive a high level of acceptance and practicability and have the potential to increase students’ physical, mental, and cognitive condition and contribute to students’ physical activity and health. While field research provides opportunities such as the testing of measures in the natural environment and producing real-life results relevant to the students and lecturers, it also imposes limitations as lecture settings differed, not all disturbances could be controlled, and the participation in the study might have led to social-desirability bias. For a sustainable development of a standing-friendly teaching and learning culture at universities, further interventions as well as the consideration of the topic in all processes and decisions within the universities are necessary. Since this study has taken place, student-life has changed drastically with COVID-19 measures. While this current paper is based on research conducted in 2019 and has only tested live lectures on campus, the tools tested could also be used for online lectures.