Physiological and metabolic responses of wheelchair athletes in different racing classes to prolonged exercise     

Campbell IG  Williams C  Lakomy HK 《Journal of sports sciences》2004,22(5):449-456

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   

Which starting style is faster in sprint running--standing or crouch start?     

Salo A  Bezodis I 《Sports biomechanics / International Society of Biomechanics in Sports》2004,3(1):43-53

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   

Editorial     

Ian D. Selwood 《Education and Information Technologies》2007,12(4):189-190

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Introduction     

Ian Winchester 《Interchange》1985,16(1):1-3

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Scratching the Surface of the History of Military Medicine     

Ian Wilson 《Metascience》2009,18(2):285-287

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‘Muscles for Motherhood’: A Genealogical Analysis of Medicalized Ways of Knowing Female Footballers in New Zealand, 1921 and 1973–1975     

Barbara Douglas Cox  Richard Pringle 《国际体育史杂志》2015,32(18):2135-2149

ABSTRACT

Michel Foucault argued that females gradually became integrated into the sphere of medical practices through a process which he termed as a ‘hysterization of women’s bodies’ (Foucault, The History of Sexuality, Volume One: An Introduction, New York: Pantheon Books, 1978, 104). In this article, we draw on Foucault to examine how women’s bodies, exercise and motherhood impacted on the historical development of female football in New Zealand within two time periods (1921 and 1973–1975). Employing his genealogical framework, we analyze newspaper reports, historical documents and conducted in-depth interviews to demonstrate how medical/scientific discourses both constrained and enabled the participation of women in football. We conclude that while medical knowledge was used to publicly disqualify the legitimacy of the female footballer in 1921, and hence her abrupt disappearance from the sporting realm, the absence of such medical knowledge in the early 1970s, combined with societal changes associated with second wave feminism, paved the way for the eventual ‘normalization’ of female football in New Zealand.  相似文献   

Geometry of screw compressor rotors and their tools     

Nikola STOSIC  Ian K. SMITH  Ahmed KOVACEVIC  Elvedin MUJIC 《浙江大学学报(A卷英文版)》2011,12(4):310-326

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   

Funding,reputation and targets: the discursive logics of high-stakes testing     

Steven Lewis  Ian Hardy 《Cambridge Journal of Education》2015,45(2):245-264

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   

‘I’m just a numbers person’: the complexity,nature and effects of the quantification of education     

Ian Hardy 《International Studies in Sociology of Education》2015,25(1):20-37

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   

Estimation of a Nonlinear Intervention Phase Trajectory for Multiple-Baseline Design Data     

Ian Hembry  Rommel Bunuan  John M. Ferron  Wim Van den Noortgate 《Journal of Experimental Education》2015,83(4):514-546

A multilevel logistic model for estimating a nonlinear trajectory in a multiple-baseline design is introduced. The model is applied to data from a real multiple-baseline design study to demonstrate interpretation of relevant parameters. A simple change-in-levels (ΔLevels) model and a model involving a quadratic function (Quadratic) for the nonlinear intervention phase data were also estimated. In addition, a simulation study was conducted to assess Markov chain Monte Carlo estimation of the logistic model and compare its trajectory recovery with use of the ΔLevels and Quadratic models. While most of the logistic model's parameter values were recovered well, trajectory recovery was very reasonable using the simpler Quadratic model. Results are discussed along with recommendations for practitioners and directions for future research.  相似文献