Jason Lezak again and again - linear mixed modelling analysis of change–over times in relay swimming races

The aim of this study was to examine the importance of the change-over time in swimming relay races. Top-class international 4 x 100 m freestyle races were analysed across a 10-year period including three Olympic Games and five European and World Championships. A total of 220 swimmers (116 female, 104 male) were included in this study with an average participation of 1.7 ± 1.2 races. To consider such repeated measurements and other factors (e.g., ranking in the relay race, position in the relay team) linear mixed models for longitudinal data were used for the statistical evaluation. Our results showed significantly longer change-over times for male medallists (0.23 ± 0.08 s) than non-medallists (0.20 ± 0.09 s) which reflects a very likely effect (94.2%). Furthermore, there were significant differences in change-over times between female and male swimmers depending on the current race positions. In total, the influence of change-over time on the final performance in 4 x 100-m freestyle relay appears to be overrated in previous studies.     

Learning relay start strategies in swimming: What feedback is best?

In the past, studies and book recommendations on relay starts in swimming have been predominantly focused on the change-over time (COT) as a performance criterion. Aside from the circular backswing start with parallel foot placement, few studies have analysed differences in the take-off movement including step approaches as well. Although trends could be identified, the results remained still somewhat inconclusive. In contrast, no study has examined as has examined whether a reduction of COT in between wall contact of the income swimmer and the take-off of the outgoing swimmer is an optimal relay start strategy, as advocated by various swimming experts. Therefore, the purpose of this study was to compare two different relay start strategies: offensive strategy minimizing COT and conservative strategy to maximize horizontal peak force (HPF). In this regard, a learning intervention with 24 elite-level swimmers (12 females, 12 male) was conducted to compare both strategies regarding relay start time, HPF and COT. Subjects were randomly assigned to two feedback groups: COT versus HPF at take-off. The results of this study showed a clear advantage for HPF feedback for relay start performance measured by wall contact of the incoming swimmer and head passage at 7.5?m of the outgoing swimmer. In addition, similar reductions in COTs were found in both training groups. In conclusion, swimmers should focus on force production rather than minimizing COT. For the latter, deteriorating consequences for force production must be considered.     

Determinanten der Studierbereitschaft unter besonderer Berücksichtigung von Studiengebühren

Even more than other European countries, Germany must fear a serious future skills shortage and lack of experts. Therefore, increasing the proportion of high school graduates who wish to study at a university is a clear political objective. The aim of this paper is to identify variables that hinder or support the decision to pursue university studies. We used longitudinal data of 23,000 graduates of upper secondary school of the years 2002, 2004, 2006, and 2008 to analyze how tuition fees (which are charged only in some of the German federal states), family status, and students?? own cost-benefit analyses impacted their decision in favor or against taking up university studies. Results showed that the subjective costs of higher education were highest for persons of low social economic background, and for women. Also, the introduction of tuition fees in some federal states in the year 2006 lowered the percentage of students who wanted to enter higher education. Contrary to our expectations, however, this effect was observed in all federal states, irrespective of whether they had introduced tuition fees or not. Our results suggest that participation in higher education can be increased by both lowering (social and psychological) costs and raising (social and psychological) benefits of higher education.     

Inclusion in Israel: coping resources and job satisfaction as explanatory factors of stress in two cultural groups

The aim of this study was to explore the differences between the two cultural groups of Jewish and Arab teachers on several variables and to analyse their link to stress. Specifically, I examined sense of coherence (SOC), sense of school community and job satisfaction among regular Jewish and Arab teachers in regular schools and classes who have special education students in their classes. Furthermore, I investigated how the different coping resources – SOC and sense of school community – explain the stress reactions of state anxiety and state anger directly and indirectly via job satisfaction and also the direct prediction of stress by job satisfaction. Data were gathered from 634 Jewish and Arab teachers (80% Jews) who completed self‐report questionnaires that measured SOC, sense of community, employee satisfaction inventory, state anxiety and state anger. Differences in SOC and sense of school community were found between the two groups such that Jews reported stronger SOC, and Arabs reported stronger sense of school community. Further differences were revealed in the links of the different coping resources to stress reactions. The results are discussed against the backdrop of cultural background and the salutogenic model.     

Self-rated competences questionnaires from a design perspective

This paper provides a theoretical review of self-rated competences questionnaires. This topic is influenced by the ongoing world-wide reform of higher education, which has led to a focus on the learner outcomes of higher education. Consequently, questionnaires on self-rated competences have increasingly been employed. However, self-ratings are often criticised for their lack of validity. Our intention is to outline some principles of good questionnaire design and to use these principles to contrast questionnaires on self-rated competences. We begin with an overview of research about questionnaire design. Then we introduce seven questionnaires and portray them in terms of their design characteristics. A comparison reveals some significant points: biographical data need to be handled more carefully, and there is an overuse of vague and abstract language. On the positive side, all of the questionnaires that were examined provide reliable sub-scales covering important facets of competences.     

制动盘表面螺旋纹理的消除方法

创新要点：提出以冲刷代替传统磨削过程对制动盘进行抛光;研究扶取规定表面质晕下的最优冲刷条件。