Relationship between physical activity,physical fitness and multiple metabolic risk in youths from Muzambinho's study

Negative associations between physical activity (PA), physical fitness and multiple metabolic risk factors (MMRF) in youths from populations with low PA are reported. The persistence of this association in moderately-to highly active populations is not, however, well established. The aim of the present study was to investigate this association in a Brazilian city with high frequency of active youths. We assessed 122 subjects (9.9?±?1.3 years) from Muzambinho city. Body mass index, waist circumference, glycaemia, cholesterolaemia, systolic and diastolic blood pressures were measured. Maximal handgrip strength and one-mile walk/run test were used. Leisure time PA was assessed by interview. Poisson regression was used in the analysis. The model explained 11% of the total variance. Only relative muscular strength and one-mile walk/run were statistically significant (p?相似文献   

Analysis of the body composition of Paralympic athletes: Comparison of two methods

Body composition is a physiological variable associated with physical activity and, in some cases, is related to athletic performance. Our objectives were to describe the body composition of participants in three distinct Paralympic sports and to compare the values of body density and estimated body fat obtained from the Paralympic athletes on the National Team by air-displacement plethysmography (ADP) and by the anthropometric method (skinfolds (SFs)). The sample consisted of 70 volunteers of both genders. The body composition of the volunteers was evaluated using the ADP in a Bod Pod^® and seven SFs. There were no significant differences between the values obtained by ADP and SF for body fat percentage (p?=?.58) and body density (p?=?.49). Analysis by Bland–Altman plots showed mean differences of 0.56?±?4.94 (?9.12–10.23) and ?0.0017?±?0.0113 (?0.024–0.020) for body fat percentage and body density, respectively. In conclusion, body composition analyses of Paralympic athletes by the ADP and SF methods show similar results, and ADP should be used as the first option when available. When the use of ADP is not possible, estimating body density and fat percentage by SF is a viable alternative for Paralympic athletes when future comparisons will use the same analysis method.     

Self-managing groups and the professional lives of teachers: A case study

The purpose of the study was to examine how interdisciplinary teaching teams were used in a newly opened Midwestern middle school to produce a work environment different from the one found in most traditionally organized schools. Five salient features of the work environment are described: organization around interdisciplinary teams, shared leadership, focus on children, the influence of the principal, and integrated programming for children. The article includes an analysis of how interdisciplinary teaching teams at this school affected some traditionally problematic aspects of teachers' work. Interdisciplinary teams are discussed as one illustration of self-managing work groups in school organizations.An earlier version of this article was presented at the annual meeting of the American Educational Research Association, New Orleans, April 7, 1988.     

Where Do We Go from Here? The Future of English Higher Education

A Delphi study has been carried out, soliciting views from higher education experts on likely and desirable developments in English higher education until 2025. The paper reports the most salient findings of the Delphi questionnaire and presents two scenarios that focus largely on the institutional fabric of the system. The first scenario follows the general agreement emerging from the two rounds of the Delphi study and suggests a smaller higher education system and the return of a binary divide between about 25 research‐intensive universities and about 70 other higher education institutions. The second scenario is a counter‐scenario that intends to present an alternative picture of English higher education in 2025. That scenario suggests a compact system of six research‐intensive universities, about 40 comprehensive institutions and five private providers. With respect to the steering of the system, a key difference between the two scenarios is that the former assumes a continuing role of market forces, whereas the latter is based on a much stronger role of the government.     

Acute and chronic effect of sodium bicarbonate ingestion on Wingate test performance: a systematic review and meta-analysis

The aim of this study was to perform a systematic review and meta-analysis on the acute and chronic effects of sodium bicarbonate (NaHCO₃) ingestion on Wingate performance. Following a search through PubMed, Scopus and Web of Science, 9 studies were found meeting inclusion criteria (6 acute and 3 chronic). Random-effects meta-analysis of standardized mean difference (SMD) for peak and mean power was performed. Study quality was assessed using the QualSyst. Results of the meta-analysis showed that acute ingestion of NaHCO₃ did not improve Wingate test peak (weighted average effect size Hedges’s g = 0.02, 95%CI: – 0.19 to 0.23, P = 0.87) or mean power (weighted average effect size Hedges’s g = 0.15, 95%CI: ?0.06 to 0.36, P = 0.92). However, chronic ingestion of NaHCO₃ improved Wingate test peak (weighted average effect size Hedges’s g = 1.21, 95%CI: 0.83 to 1.42, P = 0.001) and mean power (weighted average effect size Hedges’s g = 1.26, 95%CI: 0.96 to 1.56, P = 0.001). Quality assessment of selected articles was classified as strong. This meta-analysis provides evidence that chronic, but not acute, ingestion of NaHCO₃ increases both Wingate test peak and mean power.     

Predicting centre of mass horizontal speed in low to severe swimming intensities with linear and non-linear models

We aimed to compare multilayer perceptron (MLP) neural networks, radial basis function neural networks (RBF) and linear models (LM) accuracy to predict the centre of mass (CM) horizontal speed at low-moderate, heavy and severe swimming intensities using physiological and biomechanical dataset. Ten trained male swimmers completed a 7 × 200 m front crawl protocol (0.05 m.s^?1 increments and 30 s intervals) to assess expiratory gases and blood lactate concentrations. Two surface and four underwater cameras recorded independent images subsequently processed focusing a three-dimensional reconstruction of two upper limb cycles at 25 and 175 m laps. Eight physiological and 13 biomechanical variables were inputted to predict CM horizontal speed. MLP, RBF and LM were implemented with the Levenberg-Marquardt algorithm (feed forward with a six-neuron hidden layer), orthogonal least squares algorithm and decomposition of matrices. MLP revealed higher prediction error than LM at low-moderate intensity (2.43 ± 1.44 and 1.67 ± 0.60%), MLP and RBF depicted lower mean absolute percentage errors than LM at heavy intensity (2.45 ± 1.61, 1.82 ± 0.92 and 3.72 ± 1.67%) and RBF neural networks registered lower errors than MLP and LM at severe intensity (2.78 ± 0.96, 3.89 ± 1.78 and 4.47 ± 2.36%). Artificial neural networks are suitable for speed model-fit at heavy and severe swimming intensities when considering physiological and biomechanical background.     

Tools for Science Inquiry Learning: Tool Affordances,Experimentation Strategies,and Conceptual Understanding

Journal of Science Education and Technology - Manipulative environments play a fundamental role in inquiry-based science learning, yet how they impact learning is not fully understood. In a series...     

Sodium bicarbonate ingestion increases glycolytic contribution and improves performance during simulated taekwondo combat

Purpose: To investigate the effect of sodium bicarbonate (NaHCO₃) on performance and estimated energy system contribution during simulated taekwondo combat. Methods: Nine taekwondo athletes completed two experimental sessions separated by at least 48?h. Athletes consumed 300?mg/kg body mass of NaHCO₃ or placebo (CaCO₃) 90?min before the combat simulation (three rounds of 2 min separated by 1 min passive recovery), in a double-blind, randomized, repeated-measures crossover design. All simulated combat was filmed to quantify the time spent fighting in each round. Lactate concentration [La^?] and rating of perceived exertion (RPE) were measured before and after each round, whereas heart rate (HR) and the estimated contribution of the oxidative (W_OXI), ATP (adenosine triphosphate)-phosphocreatine (PCr) (W_PCR), and glycolytic (W_{[ La^? ]}) systems were calculated during the combat simulation. Results: [La^?] increased significantly after NaHCO₃ ingestion, when compared with the placebo condition (+14%, P?=?0.04, d?=?3.70). NaHCO₃ ingestion resulted in greater estimated glycolytic energy contribution in the first round when compared with the placebo condition (+31%, P?=?0.01, d?=?3.48). Total attack time was significantly greater after NaHCO₃ when compared with placebo (+13%, P?=?0.05, d?=?1.15). W_OXI, W_PCR, VO₂, HR and RPE were not different between conditions (P?>?0.05). Conclusion: NaHCO₃ ingestion was able to increase the contribution of glycolytic metabolism and, therefore, improve performance during simulated taekwondo combat.