The aims of this study were to examine and compare selected physiological and metabolic responses of wheelchair athletes in two paraplegic racing classes [T3: n = 8 (lesion levels T1-T7; paraplegics); T4: n = 9 (lesion levels below T7; paraplegics)] to prolonged exercise. In addition, we describe the responses of three tetraplegic athletes [T2: n = 3 (lesion levels C6/C7: tetraplegics)]. Twenty athletes completed 90 min of exercise at 75% VO2peak on a motorized treadmill adapted for wheelchairs. The mean (+/- s) heart rates of the T3 and T4 racing classes were 165 +/- 2 and 172 +/- 6 beats.min-1, respectively. For the T4 racing class, heart rate gradually increased during the test (P < 0.05), whereas for the T3 racing class, heart rate reached a plateau after an initial increase. The mean heart rate of the tetraplegics was 114 +/- 3 beats.min-1. The T3 and T4 classes exhibited similar respiratory exchange ratios, plasma lactate and glucose concentrations throughout the test. For both the T3 and T4 racing class, free fatty acid, glycerol, ammonia, urea and potassium concentrations had increased from resting values by the end of the test (P < 0.05). In conclusion, the results of this study suggest that endurance-trained wheelchair athletes are able to maintain velocities equivalent to the same relative exercise intensity (75% VO2peak) for prolonged periods irrespective of lesion level. 相似文献
The purpose of this study was to further understand the biomechanical differences between the standing and crouch starting methods, and to investigate whether one of the starting styles provides better acceleration and proves to be faster. Six university track team sprinters performed 2 x 3 x 50 m trials. Digitised video, photocell timing, and velocity data revealed that during the first steps of the performance the standing start produced higher body centre of mass horizontal velocity than the crouch start. This may be due to the longer distance between the feet in the standing start, which caused longer push-off phases, and the work against gravity in the crouch start. However, this advantage in horizontal velocity disappeared by the 10 m mark, where similar velocities were recorded with both start styles. Further, there was no statistically significant difference between the two starting styles in horizontal velocity at the 25 m mark, nor in the time to reach the 25 m or 50 m mark. Regarding relay running, where athletes need to decide to adopt either a crouch start without starting blocks or a standing start, there seems to be no specific reason for outgoing athletes to use a crouch start, although this area warrants further investigation. 相似文献
Column Editor's Note. This JLA column posits that academic libraries and their services are dominated by information technologies, and that the success of librarians and professional staff is contingent on their ability to thrive in this technology-rich environment. The column will appear in odd-numbered issues of the journal, and will delve into all aspects of library-related information technologies and knowledge management used to connect users to information resources, including data preparation, discovery, delivery and preservation. Prospective authors are invited to submit articles for this column to the editor at kenning.arlitsch@montana.edu.
The Taylor Family Digital Library is the central library opened in 2011 at the University of Calgary dedicated to supporting digital scholarship, creativity, analysis and a supportive learning environment for students. The new building is a technologically advanced converged cultural institution, with mandates to continually evolve in order to meet the needs of students and researchers. The infrastructure to support these mandates required research, collaboration and intense planning, resulting in new construction and technology standards for library renovation and construction projects. This pragmatic article is written for those who will follow in similar footsteps; it provides a roadmap for those embarking on the construction of a new technologically advanced library building. 相似文献
This paper presents a method of general geometrical definitions of screw machine rotors and their manufacturing tools. It
describes the details of lobe shape specification, and focuses on a new lobe profile, which yields a larger cross-sectional
area and shorter sealing lines resulting in higher delivery rates for the same tip speed. A well proven mathematical model
was used to determine the optimum profile, compressor housing size, and compressor ports to achieve the superior compressors. 相似文献
This paper provides insights into teacher and school-based administrators’ responses to policy demands for improved outcomes on high-stakes, standardised literacy and numeracy tests in Australia. Specifically, the research reveals the effects of the National Assessment Program – Literacy and Numeracy (NAPLAN), and associated policies, in the state of Queensland. Drawing suggestively across Michel Foucault’s notions of disciplinary power and subjectivity, and Pierre Bourdieu’s concept of social fields, the research utilises interviews with teachers and school-based administrators to reveal how high-stakes, standardised testing practices served to discursively constitute performative teacher subjectivities around issues of funding, teacher and school reputation and target-setting within what is described as the ‘field of schooling practices’. The paper argues that the contestation evident within this field is also reflective and constitutive of more educative schooling discourses and practices, even as performative logics dominate. 相似文献
This paper draws upon the sociology of numbers, particularly work by Theodore Porter, to reveal the multifarious ways in which numbers actively constitute practices in schools. Drawing upon a case study of one low-performing school in a low-performing region in the state of Queensland, Australia, and theorising into the sociology of numbers, the research explores the complex ways in which numbers came to constitute and dominate the practices in this school site under a broader national, state and regional policy context demanding rapid improvements in various forms of standardised tests and associated practices. Specifically, the research reveals a strong and simultaneous focus by teachers upon a variety of numeric data collected at national, regional and local levels, and intricate relations between these data; multiple visualisation, triangulation and comparison approaches towards such data in virtual and physical formats; and the enumerative nominalisation of both students and their reading attainment in relation to specific, concretised levels of achievement and various types of scale scores. The research cautions against the sheer volume of such enumerative practices, which, while productive of teachers’ understandings of student capacity against standardised measures of achievement, may also lead to a more reductive view of education, dominated by concerns about achievement in standardised tests (and associated practices) alone. 相似文献