In this study, we examined the effects of different work:rest durations during 20 min intermittent treadmill running and subsequent performance. Nine males (mean age 25.8 years, s = 6.8; body mass 73.9 kg, s = 8.8; stature 1.75 m, s = 0.05; VO(2max) 55.5 ml x kg(-1) x min(-1), s = 5.8) undertook repeated sprints at 120% of the speed at which VO(2max) was attained interspersed with passive recovery. The work:rest ratio was constant (1:1.5) with trials involving either short (6:9 s) or long (24:36 s) work:rest exercise protocols (total exercise time 8 min). Each trial was followed by a performance run to volitional exhaustion at the same running speed. Testing order was randomized and counterbalanced. Heart rate, oxygen consumption, respiratory exchange ratio, and blood glucose were similar between trials (P > 0.05). Blood lactate concentration was greater during the long than the short exercise protocol (P < 0.05), whereas blood pH was lower during the long than the short exercise protocol (7.28, s = 0.11 and 7.30, s = 0.03 at 20 min, respectively; P < 0.05). Perceptions of effort were greater throughout exercise for the long than the short exercise protocol (16.6, s = 1.4 and 15.1, s = 1.6 at 20 min, respectively; P < 0.05) and correlated with blood lactate (r = 0.43) and bicarbonate concentrations (r = 0.59; P < 0.05). Although blood lactate concentration at 20 min was related to performance time (r = - 0.56; P < 0.05), no differences were observed between trials for time to exhaustion (short exercise protocol: 95.8 s, s = 30.0; long exercise protocol: 92.0 s, s = 37.1) or physiological responses at exhaustion (P > 0.05). Our results demonstrate that 20 min of intermittent exercise involving a long work:rest duration elicits greater metabolic and perceptual strain than intermittent exercise undertaken with a short work:rest duration but does not affect subsequent run time to exhaustion. 相似文献
Middle-distance athletes implement a dynamic continuum in training volume, duration, and intensity that utilizes all energy-producing pathways and muscle fibre types. At the centre of this periodized training regimen should be a periodized nutritional approach that takes into account acute and seasonal nutritional needs induced by specific training and competition loads. The majority of a middle-distance athlete's training and racing is dependant upon carbohydrate-derived energy provision. Thus, to support this training and racing intensity, a high carbohydrate intake should be targeted. The required energy expenditure throughout each training phase varies significantly, and thus the total energy intake should also vary accordingly to better maintain an ideal body composition. Optimizing acute recovery is highly dependant upon the immediate consumption of carbohydrate to maximize glycogen resynthesis rates. To optimize longer-term recovery, protein in conjunction with carbohydrate should be consumed. Supplementation of beta-alanine or sodium bicarbonate has been shown to augment intra- and extracellular buffering capacities, which may lead to a small performance increase. Future studies should aim to alter specific exercise (resistance vs. endurance) and/or nutrition stimuli and measure downstream effects at multiple levels that include gene and molecular signalling pathways, leading to muscle protein synthesis, that result in optimized phenotypic adaptation and performance. 相似文献
The self-concept level of Black adolescents with African names was explored. Black males with and without African names were first identified. All participants and their parents were then administered the Terrell and Taylor Black Ideology Scale and the Coopersmith Self-Esteem Inventory. Differences between groups on the self-concept measures were then examined using a one way MANOVA with parents' scores on the self-concept measures serving as covariates. Significant differences were found between groups. Supplemental analyses revealed no differences between groups on the Coopersmith. However, adolescents with African names had significantly higher scores on the Black self-concept scales than did those without African names. 相似文献
This paper responds to a trend of contracting out subjective well-being econometrics to demonstrate social return on investment (SROI) for evidence-based policy-making. We discuss an evolving ecology of ‘external’ research taking place ‘between’ the academy and commercial consultancy. We then contextualise this as waves of research methodologies and consultancy for the cultural sector. The new model of ‘external between’ consultancy research for policy is not only placed between the University and the market, but also facilitates discourse between policy sectors, government, the media and the academy. Specifically, it enables seductive but selective arguments for advocacy that claim authority through academic affiliation, yet are not evaluated for robustness. To critically engage with an emergent form of what Stone calls ‘causal stories’, we replicate a publicly funded externally commissioned SROI model that argues for the value of cultural activities to well-being. We find that the author’s operationalisation of participation and well-being are crucial, yet their representation of the relationship problematic, and their estimates questionable. This case study ‘re-performs’ econometric modelling national-level survey data for the cultural sector to reveal practices that create norms of expertise for policy-making that are not rigorous. We conclude that fluid claims to authority allow experimental econometric models and measures to perform across the cultural economy as if ratified. This new model of advocacy research requires closer academic consideration given the changing research funding structures and recent attention to expertise and the contracting out of public services. 相似文献
Background: Within the context of sports coaching and coach education, formalised mentoring relationships are often depicted as a mentor–mentee dyad. Thus, mentoring within sports coaching is typically conceptualised as a one-dimensional relationship, where the mentor is seen as the powerful member of the dyad, with greater age and/or experience [Colley, H. (2003). Mentoring for Social Inclusion. London: Routledge].
Aim: The aim of this study was to explore the concept of a multiple mentor system in an attempt to advance our theoretical and empirical understanding of sports coach mentoring. In doing so, this paper builds upon the suggestion of Jones, Harris, and Miles [(2009). “Mentoring in Sports Coaching: A Review of the Literature.” Physical Education and Sport Pedagogy 14 (3): 267–284] who highlight the importance of generating empirical research to explore current mentoring approaches in sport, which in turn can inform meaningful formal coach education enhancement. The significance of this work therefore lies in opening up both a practical and a theoretical space for dialogue within sports coach education in order to challenge the traditional dyadic conceptualisation of mentoring and move towards an understanding of ‘mentoring in practice’.
Method: Drawing upon Kram’s [(1985). Mentoring at Work: Developmental Relationships in Organisational Life. Glenview, IL: Scott Foresman] foundational mentoring theory to underpin a multiple mentoring support system, 15 elite coach mentors across a range of sports were interviewed in an attempt to explore their mentoring experiences. Subsequently, an inductive thematic analysis endeavoured to further investigate the realities and practicalities of employing a multiple mentoring system in the context of elite coach development.
Results: The participants advocated support for the utilisation of a multiple mentor system to address some of the inherent problems and complexities within elite sports coaching mentoring. Specifically, the results suggested that mentees sourced different mentors for specific knowledge acquisition, skills and attributes. For example, within a multiple mentor approach, mentors recommended that mentees use a variety of mentors, including cross-sports and non-sport mentors.
Conclusion: Tentative recommendations for the future employment of a multiple mentoring framework were considered, with particular reference to cross-sports or non-sport mentoring experiences. 相似文献
Shifting patterns of work and leisure,together with demographic changes,an increasingly di-verse array of sport and leisure opportunities,commodification,commercialisation and globalisation have had a distinct impact on leisure and recreation/sport in many western countries,including Australia. This short paper overviews some trends in sport in contemporary Australia and discusses the question about the future of sport in this country. 相似文献
Montana's constitutional commitment to the cultural heritages of American Indians exemplifies the practical application of multicultural education. In this article, the authors explore the goals and evolution of Indian Education for All within a multicultural education framework, and discuss how educators are best prepared to implement this transformative educational policy. 相似文献