Sweat lactate response during cycling at 30°C and 18°C WBGT     

JM Green  RC Pritchett  DC Tucker  TR Crews  JR McLester 《Journal of sports sciences》2013,31(4):321-327

Sweat lactate reflects eccrine gland metabolism. However, the metabolic tendencies of eccrine glands in a hot versus thermoneutral environment are not well understood. Sixteen male volunteers completed a maximal cycling trial and two 60-min cycling trials [30°C?=?30±1°C and 18°C?=?18±1°C wet bulb globe temperature (WBGT)]. The participants were requested to maintain a cadence of 60 rev?·?min^?1 with the intensity individualized at ～ 90% of the ventilatory threshold. Sweat samples at 10, 20, 30, 40, 50 and 60?min were analysed for lactate concentration. Sweat rate at 30°C (1380±325?ml?·?h^?1) was significantly greater (P<0.05) than at 18°C (632±311?ml?·?h^?1). Sweat lactate concentration was significantly greater (P<0.05) at each time point during the 18°C trial, with values between trials tending to converge across time. During the 30°C trial, both heart rate (20, 30, 40, 50 and 60?min) and rectal temperature (30, 40, 50 and 60?min) were significantly higher than in the 18°C trial. Higher sweat lactate concentrations coupled with lower sweat rates may indicate a greater relative contribution of oxygen-independent metabolism within eccrine glands during exercise at 18°C. Decreases in sweat lactate concentration across time suggest either greater dilution due to greater sweat volume or increased reliance on aerobic metabolism within eccrine glands. The convergence of lactate concentrations between trials may indicate that time-dependent modifications in sweat gland metabolism occur at different rates contingent partially on environmental conditions.  相似文献   

Body fat measurement in elite sport climbers: Comparison of skinfold thickness equations with dual energy X-ray absorptiometry     

Vanesa España Romero  Jonatan R. Ruiz  Francisco B. Ortega  Enrique G. Artero  Germán Vicente-Rodríguez  Luis A. Moreno 《Journal of sports sciences》2013,31(5):469-477

Abstract

The aim of this study was to compare equations for estimating percentage body fat from skinfold thickness in elite sport climbers by assessing their agreement with percentage body fat measured using dual-energy X-ray absorptiometry (DXA). Skinfold thickness was measured in a convenience sample of 19 elite sport climbers [9 women and 10 men; mean age 31.2 years (s = 5.0) and 28.6 years (s = 3.6), respectively]. Percentage body fat was estimated using 17 different equations, and it was also measured by DXA. A significant inter-methods difference was observed for all equations, except for Durnin's equation in men (inter-methods difference: ?0.57% and ?0.29%; 1.96 s: 5.56 and 5.23 for Siri's and Brozek's equation, respectively) and women (inter-methods difference: ?0.67% and ?1.29% for Siri's and Brozek's equation, respectively), and for Wilmore's equation using Siri's body fat equation in women (inter-methods difference: ?1.86%). In women, the limits of agreement were lower when using Durnin's equation compared with Wilmore's equation (1.96 s: 3.86% and 5.13%, respectively). In conclusion, of the 17 studied equations, Durnin's equation was the most accurate in estimating percentage body fat in both male and female elite climbers. Therefore, Durnin's equation could be used to assess percentage body fat in elite sport climbers if more accurate methods are not available. The generalizability of the results is limited by the fact that the sample was not selected at random.  相似文献   

Contextualising Learning through the Participatory Construction of an Environmental Education Programme     

Isabel Ruiz‐Mallen  Laura Barraza  Barbara Bodenhorn  Maria de la Paz Ceja‐Adame  Victoria Reyes‐García 《International Journal of Science Education》2013,35(13):1755-1770

Strengthening links between school and community is critical for improving people’s participation in environmental issues. However, Mexican education programmes are generally unrelated to rural students’ life experience and are planned without considering either teachers’ or students’ opinions. This article describes the participatory construction of a preparatory school environmental education (EE) programme in Ixtlan de Juarez, a Mexican indigenous community internationally recognised for sustainable forest management. The qualitative research methods used are based on the action research methodology. Results from interviews conducted with the preparatory school’s headmaster, the coordinator, and nine teachers provided the needed documentation of the school site for contextualising learning activities. Feedback during focus groups with six students, three teachers, five local communal authorities, and two researchers highlighted that all participants perceived the need for creating an educational programme focused on local forest management. The contents and activities of the programme were designed by the focus group’s participants. The programme has been continuously taught by teachers and forest workers since 2005 and was officially integrated with the preparatory school science curriculum in 2006. This participative educational experience has thus transformed the mandatory school curriculum in Ixtlan.  相似文献   

TIME EXPOSURE: African American Rural Schools at the Time of the First World War     

EUGENE F. PROVENZO  JR. 《Educational Studies A Journal of the American Educational Studies Association》2013,49(3):332-333

  相似文献   

Book Review Section 2     

HENRIETTA SCHWARTZ  RONALD D. COHEN  JAMES J. SHIELDS  JR.  MAZOOR AHMED  ALBERT E. BENDER  PAUL J. SCHAFER 《Educational Studies A Journal of the American Educational Studies Association》2013,49(3-4):71-84

  相似文献   

Reviews     

DEWEY I. DYKSTRA  JR 《课程研究杂志》2013,45(6):725-740

The shift from a centralized to a decentralized school system can be seen as a solution to an uncertain problem. Through analysing the displacements in the concept of equivalence within Sweden’s decentralized school system, this study illustrates how the meaning of the concept of equivalence shifts over time, from a more collective target achievement for the educational system as a whole to a more individually interpreted goal‐fulfilment.  相似文献   

Fellows' Perceptions of a Mandatory Reflective Electronic Portfolio in a Geriatric Medicine Fellowship Program     

Jorge G. Ruiz  Syeda S. Qadri  Marina Karides  Carmen Castillo  Marcos Milanez  Bernard A. Roos 《Educational gerontology》2013,39(7):634-652

Electronic portfolios (ePortfolios) can be useful for evaluating and documenting mastery of competencies. We investigated geriatric medicine fellows' perceptions of an ePortfolio. We conducted surveys and focus groups followed by quantitative and qualitative data analysis. Our study revealed that fellows considered the ePortfolio acceptable and accessible. Fellows reflected on aspects relevant to postgraduate training and future practice and documented adherence to competencies. However, fellows expressed resentment about the self-reflection component, which interfered with the overall acceptance of the ePortfolio. Although ePortfolios can be powerful and reflective tools for competency assessment, care must be taken in their implementation.  相似文献   

Comprehensiveness and diversity in secondary compulsory education in andalusia: an unresolved challenge     

Ángel Pérez ómez  Miguel Sola FernÁndez  Javier Barquín Ruiz  Nieves Blanco  Encarnación Soto Gómez 《Educational Action Research》2013,21(4):473-492

This article outlines the contradictions and challenges of introducing comprehensive, compulsory education in Andalusia for students up to the age of 16. Following a documenting of the developments, it is argued that while the intention was for a significant, planned reform, it is better characterised as one that is, at best, an improvisation. The article discusses the continuing difficulties that may be attributed to a number of policies of the Conservative government of the day, which allowed the development of two systems of education that were not grounded in concepts of equity and social justice to evolve. The work of John Elliott has been acknowledged as an important influence upon the inquiry that was undertaken and the subsequent analysis of its results. Thus, not only are the results of an action-orientated study reported here, but also there is an extensive set of guiding principles that could enable the reform to be truly actualised.  相似文献   

Predicting athletes’ functional and dysfunctional emotions: The role of the motivational climate and motivation regulations     

Montse C. Ruiz  Saara Haapanen  Asko Tolvanen  Claudio Robazza  Joan L. Duda 《Journal of sports sciences》2017,35(16):1598-1606

This study examined the relationships between perceptions of the motivational climate, motivation regulations, and the intensity and functionality levels of athletes’ pleasant and unpleasant emotional states. Specifically, we examined the hypothesised mediational role of motivation regulations in the climate–emotion relationship. We also tested a sequence in which emotions were assumed to be predicted by the motivational climate dimensions and then served as antecedents to variability in motivation regulations. Participants (N = 494) completed a multi-section questionnaire assessing targeted variables. Structural equation modelling (SEM) revealed that a perceived task-involving climate was a positive predictor of autonomous motivation and of the impact of functional anger, and a negative predictor of the intensity of anxiety and dysfunctional anger. Autonomous motivation was a partial mediator of perceptions of a task-involving climate and the impact of functional anger. An ego-involving climate was a positive predictor of controlled motivation, and of the intensity and impact of functional anger and the intensity of dysfunctional anger. Controlled motivation partially mediated the relationship between an ego-involving climate and the intensity of dysfunctional anger. Good fit to the data also emerged for the motivational climate, emotional states, and motivation regulations sequence. Findings provide support for the consideration of hedonic tone and functionality distinctions in the assessment of athletes’ emotional states.  相似文献   

TOLERANCE, INTOLERANCE, AND PREJUDICE     

SAMUEL ENGLE BURR  JR. 《Educational theory》1952,2(2):116-120

  相似文献