Hydration,sweat and thermoregulatory responses to professional football training in the heat

Abstract

This study examined the relationship between intensity of training and changes in hydration status, core temperature, sweat rate and composition and fluid balance in professional football players training in the heat. Thirteen professional football players completed three training sessions; “higher-intensity” (140 min; HI₁₄₀), “lower-intensity” (120 min; LI₁₂₀) and “game-simulation” (100 min; GS₁₀₀). Movement demands were measured by Global Positioning System, sweat rate and concentration were determined from dermal patches and body mass change. Despite similar environmental conditions (26.9 ± 0.1°C and 65.0 ± 7.0% relative humidity [Rh]), higher relative speeds (m · min^?1) and increased perceptions of effort and thermal strain were observed in HI₁₄₀ and GS₁₀₀ compared with LI₁₂₀ (P < 0.05). Significantly (P < 0.05) greater sweat rate (L · h^?1) and electrolyte losses (g) were observed in HI₁₄₀ and GS₁₀₀ compared with LI₁₂₀. Rate of rise in core temperature was correlated with mean speed (r = 0.85), session rating of perceived exertion (sRPE) (r = 0.61), loss of potassium (K⁺) (r = 0.51) sweat rate (r = 0.49), and total sweat loss (r = 0.53), with mean speed the strongest predictor. Sodium (Na⁺) (r = 0.39) and K⁺ (r = 0.50) losses were associated with total distance covered. In hot conditions, individualised rehydration practices should be adopted following football training to account for differences in sweat rate and electrolyte losses in response to intensity and overall activity within a session.     

运动中目标设置研究的现状和存在的问题

目标设置研究是运动心理学领域的一个新课题。主要综述了近几年来国外学者对目标设置的维度、促使目标完成的有效性方法以及目标设置研究中存在的问题等方面的文献。     

Child maltreatment among school children in the Kurdistan Province, Iran

OBJECTIVE: This study examines the determinants of three types of child maltreatment: physical maltreatment, mental maltreatment, and child neglect among school children in the Kurdistan Province of Iran. The analysis examines the impact of socioeconomic, familial, demographic, and household dynamic factors on the three child maltreatment outcomes, and compares the differential impact of these factors across the three types of child maltreatment. A greater understanding of the factors associated with child maltreatment has the potential to inform public health interventions aimed at reducing specific forms of maltreatment and at identifying at risk populations. METHODS: Data were collected from 1,370 school students, age 11-18. Separate logistic models are fitted for six binary outcomes examining self-reported experiences of physical maltreatment in the home or school, mental maltreatment in the home or school, and child neglect in the home or school. RESULTS: Male children were more likely to report experiencing any kind of child maltreatment than girls. Residency in a rural area, poor parental relationships and the use of addictive substances by household members were associated with increased odds of reporting child maltreatment. Poor school performance was associated with the reporting of experiencing maltreatment at school. CONCLUSION: Each of the forms of child maltreatment is highly correlated with socioeconomic, demographic, and living condition factors. The results point to the strong influence that familial factors have in shaping a child's likelihood of reporting maltreatment. Characteristics of the mother were associated with maltreatment, but not characteristics of the father. The results highlight a number of mechanisms through which public health interventions may seek to reduce the prevalence of child maltreatment in Kurdistan; different approaches are needed to reduce child maltreatment in the home and school environments.     

Surveying Adolescent Worries: Development of the ‘Things I Worry About’ Scale

Steve Decker, Anglia Polytechnic University, Death and Loss: Compassionate Approaches in the Classroom, Oliver Leaman. London: Cassell, 1995. 160pp. hb ISBN 0 304 33087 6, pb ISBN 0 304 33089 2, price not available

Alan Dodds, The Ferrers School, Rushden, Northamptonshire, Bullying at School: What We Know and What We Can Do, Dan Olweus. Oxford: Blackwell, 1993. 140pp. pb ISBN 0 631 19241 7

Richard Smith, Elliott School, London, Combating Truancy in Schools, Edith Le Riche. London: David Fulton/ The Roehampton Institute, 1995. 112pp. ISBN 1 85346 337, £11.95

Ron Best, Roehampton Institute, London, Psychology in the Classroom: Reconstructing Teachers and Learners, Phillida Salmon. London: Cassell, 1995. 98pp. hb ISBN 0 304 33254 2, £40.00, pb ISBN 0 204 33256 9, £12.99

David Lambourn, NAPCE Base, Warwick, Primary Teachers at Work, R. J. Campbell and S. R. St.J. Neill. London: Routledge, 1994. 252pp. pb ISBN 0 415 08863 1, £14.99     

Academic procrastination of undergraduates: Low self-efficacy to self-regulate predicts higher levels of procrastination

This article reports two studies exploring the academic procrastination of 456 undergraduates. Study 1 explores the relationships among academic procrastination, self-regulation, academic self-efficacy, self-esteem, and self-efficacy for self-regulation. Results reveal that although other self-variables are related to procrastination, self-efficacy for self-regulation is most predictive of procrastination tendencies. Study 2 examines academic and motivation characteristics of “negative procrastinators,” the undergraduates who are most adversely influenced by procrastination. The 25% of 195 participants in Study 2 who were classified as negative procrastinators had significantly lower GPAs, higher levels of daily and task procrastination, lower predicted and actual class grades, and lower self-efficacy for self-regulation. After controlling for GPA, daily procrastination and self-efficacy for self-regulation significantly predicted the negative impact of procrastination. The article concludes with a discussion of the importance that self-efficacy for self-regulation holds for procrastination research, and with suggestions for practitioners who work with students who are adversely affected by procrastination.     

Implementing the flipped classroom: an exploration of study behaviour and student performance

The flipped classroom is becoming more popular as a means to support student learning in higher education by requiring students to prepare before lectures and actively engaging students during lectures. While some research has been conducted into student performance in the flipped classroom, students’ study behaviour throughout a flipped course has not been investigated. This study explored students’ study behaviour throughout a flipped and a regular course by means of bi-weekly diaries. Furthermore, student references to their learning regulation were explored in course evaluations. Results from the diaries showed that students’ study behaviour in the flipped course did not appear to be very different from that of students in a regular course. Furthermore, study behaviour did not appear strongly related to student performance in both the flipped and the regular course. Exploration of student references to their learning regulation in the course evaluations showed that some students experienced the flipped course design as intended to support their learning process. Other students, however, demonstrated resistance to changing their study behaviour even though changing study behaviour is expected in order to benefit from the flipped classroom. Further research on the relationship between students’ learning regulation and actual study behaviour and course results is necessary to understand when and why implementing the flipped classroom is successful. Recommendations that may help more effective flipped classroom implementation include considering the prior history between students and instructor(s), the broader curriculum context, and frequent expectation communication especially with large numbers of students and non-mandatory lecture attendance.     

Design and Evaluation of Digital Learning Material to Support Acquisition of Quantitative Problem-Solving Skills Within Food Chemistry

One of the modules in the course Food Chemistry at Wageningen University (Wageningen, The Netherlands) focuses on quantitative problem-solving skills related to chemical reactions. The intended learning outcomes of this module are firstly, to be able to translate practical food chemistry related problems into mathematical equations and to solve them and secondly, to have a quantitative understanding of chemical reactions in food. Until 3 years ago the learning situation for this module was inefficient for both teachers and students. For this learning situation a staff/student ratio of 1/25 was experienced to be insufficient: the level of student frustration was high and many students could not finish the tasks within the scheduled time. To make this situation more efficient for both students and teachers and to lower the level of frustration, digital learning material was designed. The main characteristic of this learning material is that it provides just-in-time information, such as feedback, hints and links to background information. The material was evaluated in three case studies in a normal educational setting (n = 22, n = 31, n = 33). The results show that now frustration of students is low, the time in classes is efficiently used, and the staff/student ratio of 1/25 is indeed sufficient. A staff student ratio of around 1/40 is now regarded as realistic.