Non-circular chainring improves aerobic cycling performance in non-cyclists

Non-circular chainrings alter the crank velocity profile over a pedalling cycle. The aim of this study was to investigate the effect of this altered crank velocity profile on the aerobic performance compared to a circular chainring (CC). Ten male non-cyclists performed two incremental maximal tests at 80?rpm on a cycle ergometer: one with a circular (Shimano) and the other with a non-circular chainring Osymetric^® (Somovedi), at least 50?h apart. Each test started with a workload of 100?W lasting 3?min. During the first 12?min, the workload was increased by 30?W every 3?min. Thereafter, the workload was increased by 30?W every 2?min until exhaustion. The power output, the intra-cycle crank angular velocity and the physiological parameters were monitored continuously, averaged over the last 30?s of each increment and at exhaustion, and compared for the two chainrings. Results showed a higher maximal aerobic power attained with the non-circular chainring (362.6?±?37.9 vs. 338.8?±?32.6?W, p?相似文献   

Muscle oxygenation and EMG activity during isometric exercise in children

The aim of this study was to examine the time-course of and the relationships between muscle oxygenation, blood volume and myoelectrical manifestations during isometric exercise in children. Twelve healthy children aged 12.5 +/- 1.2 years (mean +/- s) performed an isometric knee extension at 50% of their maximal voluntary contraction (MVC) until exhaustion to assess endurance time (limit time, T(lim)). Changes in muscle oxygenation and blood volume were assessed by near infrared spectroscopy (NIRS). The root mean square (RMS) amplitude and the mean power frequency (MPF) from electromyogram (EMG) signals were obtained, as NIRS parameters, from the vastus lateralis. Mean T(lim) was 117 +/- 34 s. The muscle oxygenation and blood volume curves decreased immediately at the beginning of exercise. Maximal deoxygenation occurred at 50% T(lim), and fell by 76.9% from the resting value. Similarly, minimal blood volume was observed at 50% T(lim); it reached a plateau that lasted until the end of exercise. The kinetics of the MPF and RMS curves were inversely related to time. At the last set of exercises (after 75% T(lim)), a steeper RMS curve and an abrupt decrease in the MPF curve were observed. Significant correlations (r) between muscle oxygenation, blood volume, root mean square amplitude and mean power frequency were observed, which ranged from 0.72 to 0.99. These findings suggest that the fatigue resulting from sustained isometric exercise is related to a decrease in oxygenation and blood volume.     

Understanding new hybrid professions: Bourdieu,illusio and the case of public service interpreters

Public spending reductions across the advanced capitalist world are creating new professions that have a ‘hybrid’ status and/or role. However, research on professional learning has paid little attention to them. This qualitative study of one such profession, public service interpreting (PSI), addresses that lacuna. The paper focuses on interpreters’ interactions with other professionals and with migrants using public services. It evokes Bourdieu’s important but neglected concept of illusio – the extent to which players invest commitment in the stakes of a field – to frame the analysis. This highlights the lack of autonomy for PSI, interpreters’ own ambiguous illusio, and their conflicts with the illusio of more powerful professions with which they must work. We conclude that there is a need for more research on the power relations between new hybrid professions and established professions, and that Bourdieu’s illusio is a potent analytical concept for this task.     

Book People in Germany: A Study on the Professional Situation and Career Conditions of Men and Women in the German Book Publishing Industry and the Book Trade

This (online) survey sheds light on gender-specific aspects/particularities of the professional activity and career development of women compared to men in this professional field. The study applies principles of theoretical and empirical knowledge from other gender-sensitive studies of professional fields in the media sector. 1,234 people completed the questionnaire (87 % women). The data shows that the field is no exception when it comes to the (poor) conditions for women. Some of the findings however exhibit interesting deviations and show, that the growing proportion of women does not turn the professional field into one where career development is equally attainable for men and women.     

Academic Institutions,Ambiguity and Learning Outcomes as Management Tools

Specifying learning outcomes (LOs) in higher education as part of the European Qualification Framework (EQF) has resulted in a variety of experiences in the national contexts of England and Norway, as well as in different institutional and disciplinary settings. This article contributes to a contextualised understanding of the kind of management tools that higher education learning outcomes (HELOs) are, based on a conceptually‐informed comparative empirical analysis. The comparison is based on two types of disciplines (the humanities and STEM) in two national contexts (Norway and England) at two research‐intensive universities in each country. These settings offer an opportunity to look for evidence – inspired by public administration literature – as to whether HELOs have some specific characteristics as management tools. HELOs share the characteristics that afflict most reform policies – that of ambiguity and the potential of being shaped by a number of circumstantial factors. Higher education institutions are highly dependent on, and embedded in, multiple relationships to the environment. Hence, as decision making structures, they are ‘penetrated’ and influenced in ways that are likely to vary across countries, types of institutions and academic disciplines. Because institutions and disciplinary groups are embedded in different policy (varying degrees and forms of state steering and policy implementation) and organisational environments (different degrees and forms of hierarchical leadership, managerial control, and autonomy) and different disciplines (different perceptions of scientific‐, professional‐, educational mission, and relationships to external stakeholders) they also constitute different organisational spaces for participation and engagement in shaping and using HELOs.     

Teaching to address diverse learning needs: development and validation of a Differentiated Instruction Scale

In the province of Quebec, Canada, a trend towards full inclusion has impelled teachers to adapt their instruction to meet the needs of both advanced and weaker learners in regular school settings. The main purpose of the present investigation was to develop and validate the Differentiated Instruction Scale (DIS), which assesses the use of instructional adaptations and academic progress monitoring strategies in general education classrooms. A total of 125 elementary school teachers participated in a cross-sectional study, allowing us to develop and validate the DIS. Overall our results show that the DIS is composed of two factors that are consistent with the predicted constructs (instructional adaptations and academic progress monitoring). Evidence of convergent validity is provided through correlations among DIS' subscales and two criteria: (1) teachers' autonomy support and (2) perceptions of school climate. Results also reveal that teachers tend to use instructional adaptations that do not require much preparation or tailored instruction. The DIS could thus be used in future research to investigate outcomes of differentiated instruction. Moreover, it could provide useful information on optimal strategies for promoting learning in children with different abilities in general education classrooms.     

Comprehension of the night and day cycle among French and Cameroonian children aged 7–8 years

Cultural Studies of Science Education - In this article, we compared French and Cameroonian schoolchildren’s initial conceptions and comprehension of the night and day cycle in order to test...