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61.
The main aim of this study was to assess the separate and combined effects of exercise and nasal splinting on static and dynamic measures of nasal airflow. In a randomized crossover design, 12 healthy participants (6 men, 6 women) performed static and dynamic spirometric nasal airflow assessment tests, with or without nasal splinting (Breathe-Right?), before and after a maximal oxygen uptake (VO 2max ) treadmill test. At least 7 days later, the V O 2max and nasal airflow tests were repeated. The results showed that the measured variables were not significantly different with and without nasal splinting. We conclude that the absence of significantly enhanced nasal patency observed for nasal splinting and after exercise suggest that these factors have a minimal impact on nasal airflow volume and rate. 相似文献
62.
E. V. Lambert J. A. Hawley J. Goedecke T. D. Noakes S. C. Dennis 《Journal of sports sciences》2013,31(3):315-324
Carbohydrate ingestion before and during endurance exercise delays the onset of fatigue (reduced power output). Therefore, endurance athletes are recommended to ingest diets high in carbohydrate (70% of total energy) during competition and training. However, increasing the availability of plasma free fatty acids has been shown to slow the rate of muscle and liver glycogen depletion by promoting the utilization of fat. Ingested fat, in the form of long-chain (C 16-22 ) triacylglycerols, is largely unavailable during acute exercise, but medium-chain (C 8-10 ) triacylglycerols are rapidly absorbed and oxidized. We have shown that the ingestion of medium-chain triacylglycerols in combination with carbohydrate spares muscle carbohydrate stores during 2 h of submaximal (< 70% VO 2 peak) cycling exercise, and improves 40 km time-trial performance. These data suggest that by combining carbohydrate and medium-chain triacylglycerols as a pre-exercise supplement and as a nutritional supplement during exercise, fat oxidation will be enhanced, and endogenous carbohydrate will be spared. We have also examined the chronic metabolic adaptations and effects on substrate utilization and endurance performance when athletes ingest a diet that is high in fat (> 70% by energy). Dietary fat adaptation for a period of at least 2-4 weeks has resulted in a nearly two-fold increase in resistance to fatigue during prolonged, low- to moderate-intensity cycling (< 70% VO 2 peak). Moreover, preliminary studies suggest that mean cycling 20 km time-trial performance following prolonged submaximal exercise is enhanced by 80 s after dietary fat adaptation and 3 days of carbohydrate loading. Thus the relative contribution of fuel substrate to prolonged endurance activity may be modified by training, pre-exercise feeding, habitual diet, or by artificially altering the hormonal milieu or the availability of circulating fuels. The time course and dose-response of these effects on maximizing the oxidative contribution of fat for exercise metabolism and in exercise performance have not been systematically studied during moderate- to high-intensity exercise in humans. 相似文献
63.
S.J. McGregor C.W. Nicholas H.K.A. Lakomy C. Williams 《Journal of sports sciences》2013,31(11):895-903
The aim of this study was to examine the effect of intermittent high-intensity shuttle running and fluid ingestion on the performance of a soccer skill. Nine semi-professional soccer players volunteered to participate in the study. Their mean (± sx ) age, body mass and maximal oxygen uptake were 20.2 ± 0.4 years, 73.2 ± 1.8 kg and 59.1 ± 1.3 ml·kg-1 ·min-1 respectively. The players were allocated to two randomly assigned trials: ingesting or abstaining from fluid intake during a 90 min intermittent exercise protocol (Loughborough Intermittent Shuttle Test:LIST).This test was designed to simulate the minimum physical demands faced by soccer players during a game. Before and immediately after performance of the test,the players completed a soccer skill test and a mental concentration test. Performance of the soccer skill test after the 'no-fluid' trial deteriorated by 5% (P ? 0.05),but was maintained during the fluid trial. Mean heart rate, perceived exertion, serum aldosterone, osmolality, sodium and cortisol responses during the test were higher (P ? 0.05) in the 'no-fluid' trial than in the fluid trial. The results of this study suggest that soccer players should consume fluid throughout a game to help prevent a deterioration in skill performance. 相似文献
64.
采用ISOMED2000等速系统检测优秀散打运动员膝、肘关节肌群的生物力学特征,分析优秀散打运动员站位攻防动作技术.在进攻训练中伸膝关节速度达到300°/s,能充分发挥运动员小腿伸肌群的爆发能力;采用300°/s的速度可以快速屈小腿,有利于运动员快速回防,为再次打击对方在时间上创造了条件;在站位时,膝关节角度保持157.3°~160.1°,小腿屈肌群离心爆发能力强,有利于运动员调整自身的身体姿势,避开对方的快速进攻.在进攻训练中应使肘关节速度达到300°/s,能充分发挥运动员前臂伸肌群的爆发能力.肘关节角度在81°~86°的范围,有利于运动员快速出拳,打击对方.以240°/s的速度屈肘,能充分发挥运动员前臂屈肌群的爆发能力,有利于运动员快速回防.在防守训练中,肘关节角度在78°~85°的范围内,对运动员快速回防,抵御时方快速、重拳的进攻是有利的;肘关节角度在128°~137°的范围内,可远距离隔挡对方,阻击对方的快速进攻. 相似文献
65.
66.
任务型语言测试观为大学英语测试(CET)提供了新的理论基础。在Bachman与Palmer的测试任务五特征基础上,创设了新题型设计基本模式,并依据该模式设计新题型对CET4测试进行了初步探索。信度和效度实证检验的结果表明,新题型组的均值虽因主观性试题量的增加而略低于旧题型组,但两者间并无显著性差异。而且新题型还呈现出同期效度值比旧题型高的态势:同时其信度系数也较高且具有显著的统计学意义。 相似文献
67.
Jack W. Kostal Paul R. Sackett Nathan R. Kuncel Philip T. Walmsley Melissa S. Stemig 《Educational Measurement》2017,36(1):39-46
Previous research has established that SAT scores and high school grade point average (HSGPA) differ in their predictive power and in the size of mean differences across racial/ethnic groups. However, the SAT is scaled nationally across all test takers while HSGPA is scaled locally within a school. In this study, the researchers propose that this difference in how SAT scores and HSGPA are scaled partially explains differences in validity and subgroup differences. Using a large data set consisting of 170,390 students each of whom matriculated at one of 114 separate colleges, the researchers find that awarding SAT scores by ranking SAT within a high school generally results in substantial reduction in the size of subgroup mean differences for this predictor. However, validity for predicting first‐year GPA is also reduced by a small amount. Conversely, placing HSGPA onto a nationally normed metric through the use of multiple regression procedures results in a moderate increase in the size of subgroup mean differences, while also producing a small increase in validity. Taken together, these findings suggest that differences in predictor scaling can partially explain differences in the size of subgroup mean differences between HSGPA and SAT scores and have implications for predictive power. 相似文献
68.
嵌入式应用领域的不断拓展,嵌入式系统的安全性和可信性越发重要,如何设计和测试一个可信的嵌入式系统是现在和未来研究的重点,尤其是嵌入式软件的可信测试技术与方法的研究。在分析软件运行剖面的基础上,依据分支路径和MM-路径测试技术,研究基于嵌入式系统的可信软件测试方法,提出一种代码覆盖和集成测试技术,用于结构覆盖测试和程序复杂度分析,指导可信软件代码设计和测试用例设计,提高软件测试效率和加速错误定位。 相似文献
69.
The paper explores academic staff and departmental research and teaching cultures in the Education Departments of five universities
in Scotland and England, countries with increasingly diverging public policies in respect of education. The relationship between
research and teaching, how the purposes of universities are defined and the status of research in Education are current UK
higher education policy preoccupations. Data is drawn from interviews with 40 academics, observation of department settings,
documentation and websites. The analysis draws on the work of Bourdieu, considering the changing habitus of individual academics,
their departmental and academic subject context and the forms of symbolic capital now required in Scottish and English Education
departments in response to new policies affecting their academic field. The paper also utilises recent literature on the research–teaching
relationship. The career trajectories of respondents, their habitus and the forms of symbolic capital that they bring to academic
life are examined, as are the extent to which the teaching and research cultures in each of the five departments studied mirror
each other and whether these also reflect the two different policy contexts. The themes how academic cultures are shaped and
research/teaching connections viewed have international as UK relevance. 相似文献
70.