体能主导类耐力性项群运动性疲劳特征与消除措施的研究

从能量代谢的视角分析体能主导类耐力性项群疲劳的特征,指出能源物质的消耗、代谢产物乳酸堆积和pH下降、体液减少和无机盐丢失是该项群发生疲劳的主要原因,并针对性地提出疲劳恢复的主要措施．体能主导类耐力性项群的训练和比赛由于运动强度、运动时间的不同,产生疲劳的机制也不尽相同,只有真正了解体能主导类耐力性项群疲劳产生的原因,才能正确、有针对性地消除运动性疲劳,提高运动成绩．     

基于能值分析的资源型城市新陈代谢水平评价——以石嘴山市为例

城市新陈代谢注重分析城市资源与能源流动过程,这为探讨资源型城市可持续发展提供了新的视角。文章以石嘴山市为例,运用能值分析方法核算2000-2013年石嘴山市各能值组成部分,通过构建代谢通量、代谢结构、能值货币比、代谢密度、代谢强度和代谢效率等指标评价石嘴山市新陈代谢水平,继而为石嘴山可持续发展提供政策建议。研究发现,石嘴山市代谢通量不断提高,但其增长率逐年降低;虽对外界环境的依赖程度逐渐提高,但当前城市经济发展仍高度依赖于不可更新资源的大量消耗;石嘴山市能值货币比逐渐下降,城市开发程度不断加大,但石嘴山市人均能值占用增长速度逐渐减少,能值利用上存在巨大的浪费,集约化程度较低,且土地经济投入粗放不紧凑,代谢强度和代谢密度难以提高;城市经济效率持续下降,而资源效率与环境效率并未得到有效的提升,这导致石嘴山市代谢效率不断下降。最后从产业转型升级、循环经济与城市土地合理利用三个角度,对提高石嘴山市城市新陈代谢机能提出建议。     

推进物质流和社会经济代谢研究,助力实现联合国可持续发展目标

实现联合国可持续发展目标的进度评估和路径选择,依赖于相关指标的定量评价及对社会经济和自然环境系统耦合关系的刻画。物质流和社会经济代谢分析方法基于质量守恒和生命周期思想,可以深刻地描述物质存量动态变化及其与流量的关系,分析资源和产品贸易及其对区域物质循环的影响,理解不同资源在生产与消费过程中的耦合与冲突关系。社会经济系统中物质代谢的分析和调控,是实现可持续发展的重要前提,也有助于绿色经济、循环经济、低碳经济等可持续发展战略的顺利实施。文章介绍了物质流和社会经济代谢分析方法的基本框架,并通过具体案例展示其如何用于分析全球、国家和产业可持续发展中的中长期资源、能源和气候挑战及相应的对策,从而助力实现联合国2030年可持续发展目标。在此基础上,提出了推进中国物质流和社会经济代谢研究的若干建议。     

Effects of different cooking methods on health-promoting compounds of broccoli

The effects of five domestic cooking methods, including steaming, microwaving, boiling, stir-frying, and stir-frying followed by boiling (stir-frying/boiling), on the nutrients and health-promoting compounds of broccoli were investigated. The results show that all cooking treatments, except steaming, caused significant losses of chlorophyll and vitamin C and significant decreases of total soluble proteins and soluble sugars. Total aliphatic and indole glucosinolates were significantly modified by all cooking treatments but not by steaming. In general, the steaming led to the lowest loss of total glucosinolates, while stir-frying and stir-frying/boiling presented the highest loss. Stir-frying and stir-frying/boiling, the two most popular methods for most homemade dishes in China, cause great losses of chlorophyll, soluble protein, soluble sugar, vitamin C, and glucosinolates, but the steaming method appears the best in retention of the nutrients in cooking broccoli. Project supported by the High-Tech R&D Program (863) of China (No. 2008AA10Z111), the National Natural Science Foundation of China (No. 30320974), the Fok Ying Tong Education Foundation of China (No. 104034), and the Program for New Century Excellent Talents in the University of China (No. NCET-05-0516)     

普通大学生健身快走运动中糖、脂代谢特征研究

运用实验法对16名普通男女大学生进行以6.5 km/h的速度1 h健身快走实验,通过文献资料法和数理统计法对实验数据进行分析,对男、女大学生在运动过程中心率、摄氧量、CO2呼出量、呼吸商以及糖、脂代谢和能量总输出量等指标变化情况进行分析,认为男生以6.5 km/h进行健身快走健身、减肥效果不明显,而女生以6.5 km/h进行健身快走,时间要控制在20 min以上才能有较好的健身减肥效果。以此为大学生进行锻炼心肺功能和健身、减肥提供参考依据。     

模拟低氧组合训练对提高我国女子400m栏速度耐力水平的探析

运用文献资料、数理统计和逻辑归纳比较法,通过比较国内外女子400m栏优秀运动员全程跑的相关数据,分析出速度耐力储备能力较国外运动员差是我国女子400m栏优秀选手以后期待解决的主要问题,根据400m栏能量供应的特点以及目前最具代表性的三种低氧耐力训练方法分析研究,从理论与实践上比较分析出较为科学有效的提高女子400 m栏运动员速度耐力水平的训练方法-模拟低氧组合训练法,模拟低氧组合训练比高原训练及单一低氧训练的更具经济性和实效性,希望能为我国女子400 m栏的速度耐力水平训练提供一些理论参考.     

Impact of data analysis methods for maximal fat oxidation estimation during exercise in sedentary adults

Abstract

The maximal fat oxidation (MFO), and the exercise intensity that elicits MFO (Fat_max), are considered excellent markers of fat metabolism during exercise. Besides individual’s biological characteristics (e.g. fed state, physical fitness level, sex, or age), data selection and analysis can affect MFO and Fatmax estimations, yet the effect is unknown. We investigated (i) the impact of using a pre-defined time interval on MFO and Fat_max estimation, and (ii) the impact of applying 2 different data analysis approaches (measured-values vs. polynomial-curve) on MFO and Fat_max estimations in sedentary adults. A total of 151 (97 women) sedentary adults aged 29.2?±?13.2 years old participated in the study. We assessed MFO and Fatmax through a walking graded exercise test using indirect calorimetry. We pre-defined 13 different time intervals for data analysis, and the estimation of MFO and Fat_max were performed through the measured-values and the polynomial-curve data analysis approaches. There were significant differences in MFO across pre-defined time intervals methods (P?<?0.001) applying measured-values data analysis approach, while no statistical differences were observed when using polynomial-curve data analysis approach (P?=?0.077). There were no differences in Fat_max across pre-defined time intervals independently of the data analysis approach (P?≥?0.7). We observed significant differences in MFO between measured-values and the polynomial-curve data analysis approaches across the time intervals methods selected (all P?≤?0.05), and no differences were observed in Fat_max (all P?≥?0.2). In conclusion, our results revealed that there are no differences in MFO and Fat_max across different time intervals methods selected using the polynomial-curve data analysis approach. We observed significant differences in MFO between measured-values vs. polynomial-curve data analysis approaches in all the study time intervals, whereas no differences were detected in Fatmax. Therefore, the use of polynomial-curve data analysis approach allows to compare MFO and Fat_max using different time intervals in sedentary adults.     

基于能值和DEA的中国城市新陈代谢效率分析

本文运用能值理论及数据包络分析方法(DEA)系统研究了2010年和2000年中国31个案例城市的新陈代谢效率特征及发展机制。结果显示,中西部城市的非可再生资源能值占系统能值总量的比例较高;而上海、北京、深圳等经济发达城市则以进出口能值为主要构成成分。2010年上海、北京、广州、深圳、沈阳、西安、杭州和海口8个案例城市达到新陈代谢效率的DEA有效,其它23个非DEA有效的城市中,绝大多数的非可再生资源投入冗余率、废弃物投入冗余率和出口改善率有待提高。此外,对城市新陈代谢效率的机制分析表明,产业结构、城市化、经济发展和人口集聚要素对于城市新陈代谢效率具有较为显著的正面影响,未来应有的放矢地从以上方面调控城市新陈代谢效率。     

The effect of glycaemic index of high carbohydrate diets consumed over 5 days on exercise energy metabolism and running capacity in males

Abstract

The aim of this study was to determine whether rates of total fat and carbohydrate oxidation and endurance capacity during running conducted in the fasted state are influenced by the glycaemic index (GI) of high carbohydrate diets consumed over 5 days. Nine healthy males performed three treadmill runs to exhaustion at 65% of maximum oxygen uptake ([Vdot]O_2max): after a habitual diet (control trial), after 5 days on a high carbohydrate/high glycaemic index diet, and after 5 days on a high carbohydrate/low glycaemic index diet in randomized counterbalanced order. No significant differences in rates of fat and carbohydrate oxidation, concentrations of plasma insulin, glucose, non-esterified fatty acids and glycerol, or time to exhaustion were observed between the high carbohydrate/high glycaemic index and high carbohydrate/low glycaemic index trials. Compared with the control trial, the concentration of plasma glycerol and rate of fat oxidation were lower (P < 0.05) and the rate of carbohydrate oxidation higher (P < 0.05) in both the high carbohydrate/high glycaemic index diet and high carbohydrate/low glycaemic index trials during the run to exhaustion. In conclusion, the extent by which a high carbohydrate diet consumed over 5 days reduces rate of fat oxidation during subsequent running exercise in the fasted state is not influenced by the glycaemic index of the diet.     

Errors in the estimation of hydration status from changes in body mass

Abstract

Hydration status is not easily measured, but acute changes in hydration status are often estimated from body mass change. Changes in body mass are also often used as a proxy measure for sweat losses. There are, however, several sources of error that may give rise to misleading results, and our aim in this paper is to quantify these potential errors. Respiratory water losses can be substantial during hard work in dry environments. Mass loss also results from substrate oxidation, but this generates water of oxidation which is added to the body water pool, thus dissociating changes in body mass and hydration status: fat oxidation actually results in a net gain in body mass as the mass of carbon dioxide generated is less than the mass of oxygen consumed. Water stored with muscle glycogen is presumed to be made available as endogenous carbohydrate stores are oxidized. Fluid ingestion and sweat loss complicate the picture by altering body water distribution. Loss of hypotonic sweat results in increased osmolality of body fluids. Urine and faecal losses can be measured easily, but changes in the water content of the bladder and the gastrointestinal tract cannot. Body mass change is not always a reliable measure of changes in hydration status and substantial loss of mass may occur without an effective net negative fluid balance.