Exercise-based injury prevention in football     

Oliver Faude  Nikki Rommers  Roland Rössler 《Sportwissenschaft》2018,48(2):157-168

Injuries—a major concern in a high-intensity contact sport like football—are associated with possible short- and long-term harmful consequences for the individual, the team and club as well as for the whole society. Consequently, there is need for effective injury prevention in football at all levels of play, in all age groups and in both genders. The present review summarizes the current scientific evidence focusing on exercise-based injury prevention and presenting promising prevention strategies in different football populations and settings. There is convincing evidence that multimodal exercise-based injury prevention programs (IPP) can reduce injury incidence by more than 30% in athletes of different age groups and in both genders. Although relevant effects have already been shown for short sessions, increased frequency and regular integration into normal practice may increase efficacy up to an injury reduction of 50%. Most programs last about 15?min and can easily replace traditional warm-up programs. Furthermore, there is increasing evidence that IPP beneficially affect neuromuscular performance parameters and biomechanical movement characteristics, which are associated with injury risk. There remains, however, a major gap between research on the short-term efficacy and long-term intervention strategies. IPP should be implemented continuously and with high fidelity as training effects are transient. It is crucial that future studies report implementation components in detail in order to facilitate the replication of successful interventions.  相似文献   

The Role of Competition in the Rise of Baroque and Renaissance Music     

Roland?VaubelEmail author 《Journal of Cultural Economics》2005,29(4):277-297

Section 1 introduces the hypothesis that competition among neighboring states may favor cultural innovation, and it surveys the available quantitative evidence. Section 2 starts from the assumption that European instrumental music had its breakthrough during the Baroque era and that the most famous composers came from the two countries characterized by the highest degree of political fragmentation: Italy and Germany. It suggests that political fragmentation has promoted musical composition and performance in several ways. The average duration of employment is proposed as a proxy for competition on the demand side. Section 3 shows that the most famous Italian and German composers of the Baroque period changed their employers significantly more often than their French and British counterparts did. Moreover, the Reformation led to musical competition between the Catholic and Protestant churches. Section 4 argues that competition for composers has also been important in other periods of European history – including competition between the Church and the courts. It shows that composers moved no less in the Renaissance than in the Baroque. Section 5 raises the question whether European music may also be said to express a competitive spirit. JEL classification: Z11  相似文献   

Editorial     

Roland S. Persson 《High Ability Studies》2001,12(2):157-158

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The relationships among independence of work habits,attitude, and achievement in an audio-tutorial physical science course     

Roland R. Pare  John W. Butzow 《科学教学研究杂志》1975,12(1):1-3

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Avoiding and Correcting Bias in Score-Based Latent Variable Regression With Discrete Manifest Items     

Irene R. R. Lu  D. Roland Thomas 《Structural equation modeling》2013,20(3):462-490

This article considers models involving a single structural equation with latent explanatory and/or latent dependent variables where discrete items are used to measure the latent variables. Our primary focus is the use of scores as proxies for the latent variables and carrying out ordinary least squares (OLS) regression on such scores to estimate parameters in the structural equation. We are concerned with the bias in these OLS estimates; we present two approaches to deal with this bias. Extending the work of Skrondal and Laake (2001) Skrondal, A. and Laake, P. 2001. Regression among factor scores. Psychometrika, 66: 563–576. [Crossref], [Web of Science ®] , [Google Scholar] on continuous items, we derive sufficient conditions under which the use of scores based on item response theory leads to unbiased OLS estimates at the population level; we deem this approach “bias avoiding.” We also consider Croon's (2002) Croon, M. 2002. “Using predicted latent scores in general latent structure models”. In Latent variable and latent structure models, Edited by: Marcoulides, G. A. and Moustaki, I. 195–223. Mahwah, NJ: Lawrence Erlbaum Associates, Inc.  [Google Scholar] bias correction methodology for continuous items and explore its efficacy on discrete items; we deem this approach “bias correcting.” We illustrate the performance of the 2 approaches through numerical examples of large simulated data sets.  相似文献   

Determinants of perceived usefulness of social media in university libraries: Subjective norm,image and voluntariness as indicators     

Roland Izuagbe  Goodluck Ifijeh  Edith I. Izuagbe-Roland  Olajumoke Rebecca Olawoyin  Lilofa Osamenfa Ogiamien 《The Journal of Academic Librarianship》2019,45(4):394-405

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Teachers’ Autonomy in Today's Educational Climate: Current Perceptions From an Acceptable Instrument     

Luman E. G. Strong  Roland K. Yoshida 《Educational Studies A Journal of the American Educational Studies Association》2014,50(2):123-145

This research evaluated the psychometric properties of Friedman's (1999) Teacher Work-Autonomy Scale (TWA) to determine whether it was an acceptable instrument to measure U.S. teacher autonomy in the present educational context. A second purpose was to ascertain the current status of teachers’ perceptions of their autonomy from a sample of U.S. teachers. Four hundred seventy-seven teachers from three public schools in Michigan participated in this study for a response rate of 30%. Factor analysis confirmed the multifaceted nature of teacher autonomy; however, somewhat different factor structures were found for the elementary and secondary teachers in this study, in comparison to that of Friedman. The TWA, without major modifications, appeared to be a valid and reliable instrument for use with a U.S. secondary sample but with limitation with an elementary sample. Elementary and secondary teachers perceived autonomy in the different factors in identical order, but with significant differences between their scores. Differences in school structure and conceptions of autonomy may have contributed to grade-level discrepancies. The findings suggest that administrators may be able to enhance teacher autonomy by releasing some of their power to include teachers in school leadership, specifically in the two areas teachers perceived with lowest autonomy: school finances and professional development.  相似文献   

Metabolic Thresholds and Validated Accelerometer Cutoff Points for the Actigraph GT1M in Young Children Based on Measurements of Locomotion and Play Activities     

Gerda Jimmy  Alain Dössegger  Roland Seiler  Urs Mäder 《Measurement in physical education and exercise science》2013,17(1):23-40

The purpose of the current study was to determine metabolic thresholds and subsequent activity intensity cutoff points for the ActiGraph GT1M with various epochs spanning from 5 to 60 sec in young children. Twenty-two children, aged 4 to 9 years, performed 10 different activities including locomotion and play activities. Energy expenditure was measured with indirect calorimetry. Thresholds and cutoff points were determined through receiver operating characteristic curves. The lower metabolic threshold was 6.19 kcal·kg^?1·h^?1 for moderate and 9.28 kcal·kg^?1·h^?1 for vigorous intensity. The cutoff points for the GT1M accelerometer appear to be lower than those for the previous model (7164). For 5-sec epochs, a cutoff point of 143 counts resulted for moderate intensity and of 208 counts for vigorous intensity activity. Whether short or long epochs were chosen when collecting data to determine cutoff points, does not appear to have an influence on the resulting cutoff values. Similarly, comparable results are seen when analyses are based on locomotion only as opposed to a wide range of activities including children's play.  相似文献   

The Decline of Women Leaders (Coaches and Athletic Directors) in Girls' Interscholastic Sport Programs in Virginia from 1972 to 1987     

Mary Frances Heishman  Linda Bunker  Roland W. Tutwiler 《Research quarterly for exercise and sport》2013,84(1):103-107

Abstract

The purpose of this study was to determine if static and baltislic stretching would, induce significant amounts of delayed onset muscle soreness (DOMS) and increases in creatine kinase (CK). Twenty males were randomly assigned to a static (STATIC) or ballistic stretching (BALLISTIC) group. All performed three sets of 17 stretches during a 90-min period, the only group difference being that STATIC remained, stationary during each 60-s stretch while BALLISTIC performed, boundng movements. Subjective ratings of DOMS (scale: 1–10) and serum CK levels were assessed before and every 24 hours post stretching, for 5 days. A repeated measures ANOVA revealed a significant main effect due to time (p < .05), with peak soreness occurring at 24 hours after (M = 2.8 ? 1.6). Surprisingly, a group effect (p < .05) demonstrated. that DOMS was significantly greater for STATIC than for BALLISTIC. At 24 hours there was a 62% (p < .05) increase in CK for combined groups. These findings indicate that similar bouts of static and ballistic stretching induce significant increases in DOMS and CK in subjects unaccustomed to such exercise. Furthermore, static stretching induced significantly more DOMS than did ballistic.  相似文献   

Physical activity, nutrition, screen time and sleep associated with body weight and physical condition in young children     

Monique L’Hoir PhD  Susanne Tetteroo BSc  Magda Boere-Boonekamp MD  PhD  Elly Kloeze MSc  Ingrid Bakker PhD  Francisca Galindo Garre PhD  Prof. Dr. Roland Naul 《Sportwissenschaft》2013,43(2):116-123

The aim of this cross-sectional study was to explore the possible relationship between (un)healthy behaviour and (over)weight and physical condition in families with young children (4–7 years), in a village (30,000 inhabitants) in the eastern part of the Netherlands, close to Germany. It is one of two pilot studies as a precursor of a cross-border project including six Dutch and six German villages, to counteract physical inactivity and possible future metabolic problems. In total, 459 children of five elementary schools and their parents were included. Parents were requested to fill in a questionnaire on the nutritional, physical, sedentary, and sleeping behaviour of their child. Relevant background characteristics were obtained and lifestyle classifications were made. At school, the children's height and weight (body mass index (BMI)) were measured, as well as their physical condition (two tests) and basic motor abilities (four physical exercise tests). The relationship between the standardized BMI z-scores and physical condition test scores, and nutritional, physical, sedentary and sleeping habits was analysed using independent sample t-test, bivariate correlation analysis and multiple regression analysis. Latent class analysis was used to identify clusters of people based on their nutritional, physical and sleep habits. Of the parents, 376 (82?%) were willing to fill out the questionnaire. High birth weight and a high BMI of the mother and/or father correlated with a higher BMI of the child (ρ?=?0.28, p?<?0.001; ρ?=?0.13, p?=?0.016; and ρ?=?0.23, p?<?0.001, respectively). Daily playing outside, eating small cookies (compared with large cookies) and no sleeping problems (no waking up during the night) were related to low BMI levels (no overweight) [ρ?=???0.14, p?=?0.005; ρ?=???0.12, p?=?.020; t(364)?=?1.81, p?=?0.072 (trend), respectively]. Daily playing outside (frequency and duration) and being a member of a sports club were related to positive scores on the physical condition tests [ρ?=?0.20, p?<?0.001; t(365)?=???2.99, p?=?0.003, respectively]. High levels of television (TV) watching and general sleeping problems were related to a less optimal physical condition [ρ?=???0.09, p?=?0.076 (trend); and ρ?=???0.10, p?=?0.059 (trend), respectively]. A latent class analysis revealed three clusters: 46?% of the sample belonged to the ‘healthy group’ concerning nutrition, sedentary lifestyle and TV/personal computer (PC) use; 17?% to the ‘less healthy’ group and 37?% to a group with nutrition and physical activity habits close to the healthy group, but with low conditional probabilities for the sleeping items. Conducting a pilot study before the start of a binational intervention study gives a blueprint for the final questionnaire, and clues for tailored interventions in the schools, as proposed in the approach of ‘Gesunde Kinder in gesunden Kommunen’ (GKGK). The results of a latent class analysis underscore that interventions should exist of a multi-component strategy, focusing on promoting physical activity, healthy nutrition habits and appropriate sleep.  相似文献