Intensity of Treadmill Training and its Effect on Body Composition in Rats

Abstract

The purpose of this study was to determine which of three intensities of treadmill training produced changes in body composition in rats as evidenced by body weight, percentage of fat and specific gravity. Subjects were 60 male Wistar rats 25 to 30 days old when obtained. They were randomly assigned to one of five groups: sedentary controls, spontaneously active controls, and three groups of rats forced to exercise on a treadmill at intensities of 75, 125 and 175 fpm. Forced exercise was applied three times a week for 8 weeks, after which measures of body weight, specific gravity, and percentage of body fat were obtained. Results indicated that the sedentary controls had significantly higher mean body weights than did those which exercised. Rats forced to exercise at 75 fpm had significantly lower specific gravity measures than rats trained at 125 fpm. Sedentary controls had lower specific gravity values than did all rats allowed to exercise. Intensity of treadmill training had no effect on percentage of body fat as determined chemically. However, exercise was effective in reduction of body fat.     

Muscle Fiber Type Composition and Knee Extension Isometric Strength Fatigue Patterns in Power- and Endurance-Trained Males

Abstract

Muscle fiber type composition in the vastus lateralis and knee extension isometric strength fatigue patterns were assessed in eight endurance-trained and eight power-trained males. Two different 25-trial isometric contraction exercise regimens were administered: a 10-second contraction, 5-second intertrial rest condition designed to induce a fast rate of fatigue and a 10-second contraction, 20-second intertrial rest condition designed to induce a slower rate of fatigue. The power group fatigued almost four times faster than the endurance group in the 10:5 exercise condition. In the 10:20 exercise condition, the endurance group showed no fatigue pattern while the power group had a significant strength decrement of 32%. In both exercise conditions, the power group exhibited more complex fatigue patterns in terms of statistically significant trend components. Maximum isometric strength correlated positively with slow twitch (ST) percent number in power (r = .80) and endurance (r = .48) groups, but negatively with linear trend coefficients in endurance (r = -.62) and power (r = -.80) groups. Maximum isometric strength also correlated higher with fatigue curve trend coefficients than did muscle fiber type composition. Thus, a faster rate of fatigue was associated with higher maximum isometric strength and with higher ST percent number and area. Since maximum isometric strength correlated with body weight (r = .86 for groups combined), both maximum isometric strength and muscle mass appear to be more important determinants of knee extension isometric strength fatigue patterns than muscle fiber type composition.     

Observing Coaches’ Leadership Behaviours: the Development of the Coach Leadership Assessment System (CLAS)

ABSTRACT

The purpose of the present study was to develop an observational coding system that examines coaches’ leadership behaviours in sport. Drawing from an integration of the dimensions emphasized within the full-range leadership model, and particularly, transformational leadership (TFL), the Coach Leadership Assessment System (CLAS) was designed to examine coaches’ real-time leadership behaviours. Behavioural categories were developed through an iterative combination of literature review, qualitative interviews, and video observation. The CLAS consists of five higher-order dimensions: transformational, transactional, neutral, laissez-faire, and toxic coaching, which assess coaches’ leadership across 18 distinct behavioural categories. Overall, results provided preliminary support for the reliability and validity of this instrument. The CLAS provides a detailed and contextualized account of coaches’ leadership behaviours in sport and may have important implications for theory development and applied practice.     

THE DIFFERENCES IN SCORES AND SELF-EFFICACY BY STUDENT GENDER IN MATHEMATICS AND SCIENCE

Typically, mathematics and science are seen as linked together, where both subjects involve numbers, critical thinking, and problem solving. Our study aims to develop a better understanding of the connections between student’s achievement scores in mathematics and science, student gender, and self-efficacy. We used the Trends in International Mathematics and Science Study 2007 eighth grade data to answer our research questions and were able to demonstrate that when controlling for self-efficacy, there is a statistically significant difference in the achievement scores between males and females by subject, where females score higher Algebra, but males score higher in the other mathematics subjects. Likewise, we were also able to demonstrate that there is a statistically significant difference in the achievement scores in Earth Science, Physics, and Biology, between males and females where males score higher in science subjects. In both mathematics and science examinations, we controlled for self-efficacy where in mathematics females hold lower self-efficacy then males and in science there is no difference between females and males in terms of self-efficacy. We conjecture that mathematics and science classrooms that consider self-efficacy may impact student’s achievement scores by subject, which can ultimately impact career choices in mathematics- and science-based fields.     

Developing Mobile Based Instruction

This paper describes an instructional design class??s experience developing instruction for the mobile web. The class was taught at a southeastern university in the United States in a master??s level computer based instruction course. Two example projects are showcased and student reflections on design issues are highlighted. Additionally, challenges and lessons learned from this experience are described. This case study will benefit those who are considering teaching a course on designing mobile learning; also to those who are considering developing mobile instructional websites.     

Collaborative research in contexts of inequality: the role of social reflexivity

This article reports on the role and value of social reflexivity in collaborative research in contexts of extreme inequality. Social reflexivity mediates the enablements and constraints generated by the internal and external contextual conditions impinging on the research collaboration. It fosters the ability of participants in a collaborative project to align their interests and collectively extend their agency towards a common purpose. It influences the productivity and quality of learning outcomes of the research collaboration. The article is written by fourteen members of a larger research team, which comprised 18 individuals working within the academic development environment in eight South African universities. The overarching research project investigated the participation of academics in professional development activities, and how contextual, i.e. structural and cultural, and agential conditions, influence this participation. For this sub-study on the experience of the collaboration by fourteen of the researchers, we wrote reflective pieces on our own experience of participating in the project towards the end of the third year of its duration. We discuss the structural and cultural conditions external to and internal to the project, and how the social reflexivity of the participants mediated these conditions. We conclude with the observation that policy injunctions and support from funding agencies for collaborative research, as well as support from participants’ home institutions are necessary for the flourishing of collaborative research, but that the commitment by individual participants to participate, learn and share, is also necessary.     

Supporting Student Discussions: it isn't Just Talk

The role of dialogue in learning is considered with respect to the use of educational technology. The Vicarious Learner project aims to create a re-usable resource base of learning dialogues from which later learners can benefit. This depends on effective dialogues arising within computer-based media, so that they can be captured. The conditions for effective dialogue are dependent not only on the technology, but on structures and conventions surrounding its use. Two studies are described, from which it emerges that new structures are needed. A notion of Task Directed Discussions (TDDs) is developed, through which effective dialogues are explicitly encouraged. A theoretical framework for the re-use of such dialogues is described. © IFIP, published by Kluwer Academic Publishers