Injury rates in professional soccer players during Ramadan     

Chamari K  Haddad M  Wong del P  Dellal A  Chaouachi A 《Journal of sports sciences》2012,30(Z1):S93-102

Many of the socio-cultural lifestyle and dietary changes that take place during Ramadan may affect the risk of injury in athletes, but little evidence is available. The aim of the present study was to examine the effects over two consecutive years of the holy month of Ramadan on injury rates in 42 professional players of a Tunisian top-level professional soccer team. Players were retrospectively organized into fasting and non-fasting groups and monitored for 3 months: 4 weeks before Ramadan, during the month of Ramadan (4 weeks), and 4 weeks after Ramadan each year. During Ramadan, training started at 22.00 h. The circumstances (training/match) and mechanism of injury (traumatic/overuse) were recorded. No significant differences between the three periods were observed for weekly mean training load, training strain, training duration, and Hooper's Index (quality of sleep, and quantities of stress, delayed-onset muscle soreness, and fatigue). Compared with non-fasting players, fasters had a lower (P < 0.05) Hooper's Index and stress during and after Ramadan. No significant difference in injury rates was observed between fasting and non-fasting players. Nevertheless, the rates of non-contact (6.8 vs. 0.6 and 1.1) and training overuse (5.6 vs. 0.6 and 0.5) injuries were significantly higher in fasting players during the month of Ramadan than before or after Ramadan. In conclusion, Ramadan, along with the corresponding changes in nutritional habits, sleeping schedule, and socio-cultural and religious events, significantly increased overuse and non-contact injuries in fasting players despite the fact that the training load, strain, and duration were maintained.  相似文献   

General Growth Mixture Analysis of Adolescents' Developmental Trajectories of Anxiety: The Impact of Untested Invariance Assumptions on Substantive Interpretations     

Alexandre J. S. Morin  Christophe Maïano  Benjamin Nagengast  Herbert W. Marsh  Julien Morizot  Michel Janosz 《Structural equation modeling》2013,20(4):613-648

Substantively, this study investigates potential heterogeneity in the developmental trajectories of anxiety in adolescence. Methodologically, this study demonstrates the usefulness of general growth mixture analysis (GGMA) in addressing these issues and illustrates the impact of untested invariance assumptions on substantive interpretations. This study relied on data from the Montreal Adolescent Depression Development Project (MADDP), a 4-year follow-up of more than 1,000 adolescents who completed the Beck Anxiety Inventory each year. GGMA models relying on different invariance assumptions were empirically compared. Each of these models converged on a 5-class solution, but yielded different substantive results. The model with class-varying variance–covariance matrices was retained as providing a better fit to the data. These results showed that although elevated levels of anxiety might fluctuate over time, they clearly do not represent a transient phenomenon. This model was then validated in relation to multiple predictors (mostly related to school violence) and outcomes (grade-point average, school dropout, depression, loneliness, and drug-related problems).  相似文献   

Disentangling Shape from Level Effects in Person-Centered Analyses: An Illustration Based on University Teachers’ Multidimensional Profiles of Effectiveness     

Alexandre J. S. Morin  Herbert W. Marsh 《Structural equation modeling》2013,20(1):39-59

This study compares alternative ways of disentangling the effects of level (the tendency for a person to be high, medium, or low across all factors) and shape (the tendency for a person to have a distinct pattern of factors on which they are high, medium, or low) in profile analyses. This issue is particularly relevant to performance appraisals where it is often useful to identify specific strengths and weaknesses over and above a person global performance, but also to person-centered analyses more generally where the observation of qualitative (shape) differences between profiles is often used as justification for the added value of profiles. Substantively, this study illustrates these issues in the identification of profiles of teachers based on multidimensional students’ ratings of their effectiveness, using an archival data set of 31,951 class-average ratings based on the Students’ Evaluations of Educational Quality (SEEQ) instrument collected over a 13-year period. The results show the superiority of a factor mixture operationalization of teaching effectiveness in which a global effectiveness factor was used to control for unnecessary level effects in the profiles.  相似文献   

The ‘invention’ of FIFA history: João Havelange’s election to FIFA presidency as a historic event     

Luiz Guilherme Burlamaqui 《Soccer & Society》2019,20(7-8):1056-1070

ABSTRACT

In 1974, the Brazilian sports official João Havelange was elected FIFA’s president in a two-round election, defeating the incumbent Stanley Rous. The upset, often attributed to a successful alliance with Asia, the Middle East and Africa, what at the time was referred to as the Third World – surprised observers everywhere. Here, the election can be analysed as a historically relevant event of social significance. It can be thought of as a political window by means of which the international dynamic of a specific moment in the Cold War can be perceived, especially the limitations and potentialities of the agency available to periphery countries at that time. In this article, I intend to discuss the narratives that forged the history of FIFA, which take this political ‘event’ as a key in the institution’s own historical transformation. The sources analysed will be mainly FIFA official histories, such as the FIFA News, FIFA historical books and movies about the history of FIFA.  相似文献   

Correlation analysis of performance measures for multi-label classification     

Rafael B. Pereira  Alexandre Plastino  Bianca Zadrozny  Luiz H.C. Merschmann 《Information processing & management》2018,54(3):359-369

In many important application domains, such as text categorization, scene classification, biomolecular analysis and medical diagnosis, examples are naturally associated with more than one class label, giving rise to multi-label classification problems. This fact has led, in recent years, to a substantial amount of research in multi-label classification. In order to evaluate and compare multi-label classifiers, researchers have adapted evaluation measures from the single-label paradigm, like Precision and Recall; and also have developed many different measures specifically for the multi-label paradigm, like Hamming Loss and Subset Accuracy. However, these evaluation measures have been used arbitrarily in multi-label classification experiments, without an objective analysis of correlation or bias. This can lead to misleading conclusions, as the experimental results may appear to favor a specific behavior depending on the subset of measures chosen. Also, as different papers in the area currently employ distinct subsets of measures, it is difficult to compare results across papers. In this work, we provide a thorough analysis of multi-label evaluation measures, and we give concrete suggestions for researchers to make an informed decision when choosing evaluation measures for multi-label classification.  相似文献   

Effects of Different Chair-Based Exercises on Salivary Biomarkers and Functional Autonomy in Institutionalized Older Women     

Taís Rieping  Guilherme Eustáquio Furtado  Matheus Uba Chupel  Juan C. Colado  Eef Hogervorst 《Research quarterly for exercise and sport》2019,90(1):36-45

Purpose: The aim of this study was to test the effects of chair-based exercise programs on salivary stress hormones, physical fitness, and functional autonomy of institutionalized older women. Method: In total, 47 participants (80 ± 8.04 years old) were recruited and allocated into three groups: chair-based aerobic exercises (CAE, n = 19), chair-based elastic-band strength exercises (CSE, n = 15), and a control group (CG, n = 13). A 14-week exercise intervention was done for the CAE and CSE groups, two times per week, in no consecutive days. Members of the CG did not participate in any type of exercise but kept their regular lifestyle. Fear of falling, autonomy, physical fitness, salivary cortisol, and alpha-amylase levels were assessed before and after the intervention. Results: The CAE group improved upper and lower body strength, agility–dynamic balance, and autonomy, with fear of falling decreasing significantly (p < .05, moderate effect size). Both exercise groups showed a trend toward an increase in salivary alpha-amylase levels (CAE = 43%, d = .31, and CSE = 44%, d = .41). Conclusion: Both exercise programs were able to improve functional autonomy, even in elders older than 80 years of age. It might be interesting to investigate the effectiveness of combining both aerobic and strength exercises in a unique protocol. The modulation effect of exercise in the hormonal responses needs to be further explored.  相似文献   

Assessing visibility,legibility and comprehension for interactive whiteboards (IWBs) vs. computers     

Olga Megalakaki  Alexandre Porion  Léa Pasqualotti  Thierry Baccino 《教育心理学》2016,36(9):1631-1650

The usability of interactive whiteboards vs. computers was evaluated on three dimensions (visibility, legibility and comprehension) in the secondary school pupils. The visibility assessment consisted in detecting a visual stimulus varying in luminance using a staircase procedure, legibility was assessed with a target-search task, and we administered narrative and explanatory texts with or without illustrations to evaluate comprehension. The results of the visibility test showed that pupils found the light signal easier to detect on the IWB. For the legibility test, we observed differences in error rates and discriminability according to medium, font size and congruence between target and the distractor letters. Performances in the comprehension test were similar for both explanatory and narrative texts. Moreover, the presence of illustrations does not improve comprehension. These results could be related to the hierarchical structure of the texts, which facilitate comprehension.  相似文献   

The process of internationalisation of higher education in Brazil: the impact of colonisation on south-south relations     

Alexandre Guilherme  Marilia Morosini  Pricila Kohls dos Santos 《Globalisation, Societies & Education》2018,16(4):409-421

ABSTRACT

This article presents a study that analyses interviews of African students participating in the PEC academic mobility programme, so to gain an understanding of the individual and corporate experience of living and studying in Brazil. However, our analysis also demonstrates a highly significant finding that the historical process of colonisation, experienced for centuries by the Great South, has impinged on the outlook held by individuals from the Great South, who tend to understand that the Great North is the desirable option. Consequently, this attitude has directly affected South-South relations and the cooperation between developing and emerging countries. The work of Franz Fanon, who is a pivotal figure in the process of decolonisation, serves as a framework for our analysis because it both conceptualises and demonstrates the symptoms of psychological violence in a colonised context. As it will become clear, this has ramifications for the process of internationalisation and globalisation of Higher Education.  相似文献   

A Bifactor Exploratory Structural Equation Modeling Framework for the Identification of Distinct Sources of Construct-Relevant Psychometric Multidimensionality     

Alexandre J. S. Morin  A. Katrin Arens  Herbert W. Marsh 《Structural equation modeling》2016,23(1):116-139

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Physiological responses according to rules changes during 3 vs. 3 small-sided games in youth soccer players: stop-ball vs. small-goals rules     

Jamel Halouani  Alexandre Dellal  Anis Chaouachi  Karim Chamari 《Journal of sports sciences》2013,31(15):1485-1490

Abstract

Small-sided games (SSGs) are effective for soccer-specific aerobic endurance training. To date, no study has investigated the effect of stop-ball (SB-SSG) rule on the physiological responses to SSG. Therefore, the purpose of the present study was to examine the effects of SB-SSG vs. small-goals (SG-SSG) rules on physiological responses during a 3 vs. 3 SSG in young soccer players. Twelve male amateur young soccer players (age, 14.0 ± 0.7 years; body mass, 51.8 ± 8.0 kg; height, 164 ± 7 cm) randomly performed either SB-SSG or SG-SSG for 4 × 4 min separated by 2 min of recovery on a 20 × 15 m pitch. During the SB-SSG, participants were instructed to stop the ball with the soles of their boots in a 15 × 1 m surface behind the pitch bottom line; whereas during the SG-SSG, the participants were instructed to score to a mini-goal (i.e., 1 × 0.5 m). During each test session, the mean heart rate (HR), the post-SSG rating of perceived exertion (RPE) scores and blood lactate concentrations ([La^?]) were recorded. Results showed that SB-SSG induced significantly higher mean HR (178 ± 3 vs. 174 ± 3 bpm; P < 0.05) and [La^?] (4.66 ± 0.98 vs. 4.16 ± 1.02 mol · L^–1; P < 0.05) than SG-SSG. However, there was no significant difference between SB-SSG and SG-SSG for the RPE scores. In conclusion, the present study demonstrates the effectiveness of SB-SSG in SSG training. Indeed, SB-SSG can influence the effort intensity in SSG (i.e., resulted in a higher intensity than SG-SSG). Therefore, coaches have the possibility to choose between SB-SSG and SG-SSG rules during training sessions according to their physical and technical objectives.  相似文献