高温高湿环境中运动前补液方法及效果研究

目的:在高温高湿环境中,脱水现象构成了对大众健身人群健康和运动能力的极大挑战,本研究旨在通过对25名自行车爱好者进行运动前补充含一定量甘油的运动饮料的方法,探究运动前补充甘油饮料对人体保水能力和运动能力的影响,为大众健身人群更好地使用甘油超水合补水法提供理论和实践依据。方法:本实验中的25名北京地区的自行车爱好者平均年龄为27.4±5.58岁,形成自身对照。运动员补充饮料后在模拟高温高湿环境训练房进行递增负荷的功率自行车运动(温度控制在35±2℃,湿度控制在60±5%),并监测其尿量、体重下降值、血乳酸、运动持续时间等指标。采用SPSS17.0统计软件包分析数据。结果:1)甘油补充对体重的影响:两组运动前后体重变化值有非常显著性差异(P<0.01);2)甘油补充对排尿量的影响:甘油实验组的运动后尿量和总尿量均明显著低于安慰对照组(P<0.05);3)甘油补充对运动持续时间的影响:甘油实验组的运动持续时间显著长于安慰对照组(P<0.01);4)甘油补充对血乳酸的影响:甘油实验组运动后即刻的血乳酸浓度明显低于安慰对照组(P<0.05)。结论:1)通过运动前后体重变化和排尿量的变化对比,表明运动前甘油补充可显著增加机体的储水能力;2)通过对安慰对照组和甘油实验组运动持续时间的对比研究表明,甘油补充组运动持续时间显著长于安慰对照组,进一步表明运动前补充甘油饮料有助于延缓运动疲劳的产生,延长运动时间;3)通过对安慰对照组和甘油实验组血乳酸的监测结果表明,甘油饮料的保水效果可显著降低机体因运动产生的代谢酸性物质,从而延缓运动疲劳。     

试析晚清文化传播的两种模式

晚清的文化传播呈现出两种不同模式。精英化的文化传播模式极力展现有关国家民族的政治理念等宏大叙述,体现出传播主体精英化的身份特征和价值立场,在特定时期有其历史意义,也有自身缺陷。大众化的文化传播模式突出普通民众的审美情趣和心理体验,体现了晚清民间知识分子的价值取向,有着精英文化传播模式不可替代的社会意义。     

质点组内力的功改变质心动能的条件

讨论了质点组内力的功是可以改变质心动能的，以及所满足的条件．     

A comparison of methods to determine bilateral asymmetries in vertical leg stiffness

Whilst the measurement and quantification of vertical leg stiffness (K_vert) asymmetry is of important practical relevance to athletic performance, literature investigating bilateral asymmetry in K_vert is limited. Moreover, how the type of task used to assess K_vert may affect the expression of asymmetry has not been properly determined. Twelve healthy males performed three types of performance tasks on a dual force plate system to determine K_vert asymmetries; the tasks were (a) bilateral hopping, (b) bilateral drop jumping and (c) unilateral drop jumping. Across all the three methods, K_vert was significantly different between compliant and stiff limbs (P < 0.001) with a significant interaction effect between limb and method (P = 0.005). Differences in K_vert between compliant and stiff limbs were ?5.3% (P < 0.001), ?21.8% (P = 0.007) and ?15.1% (P < 0.001) for the bilateral hopping, bilateral drop jumping and unilateral drop jumping methods, respectively. All the three methods were able to detect significant differences between compliant and stiff limbs, and could be used as a diagnostic tool to assess K_vert asymmetry. Drop jumping tasks detected larger K_vert asymmetries than hopping, suggesting that asymmetries may be expressed to a greater extent in acyclic, maximal performance tasks.     

Dribbling determinants in sub-elite youth soccer players

Dribbling speed in soccer is considered critical to the outcome of the game and can assist in the talent identification process. However, little is known about the biomechanics of this skill. By means of a motion capture system, we aimed to quantitatively investigate the determinants of effective dribbling skill in a group of 10 Under-13 sub-elite players, divided by the median-split technique according to their dribbling test time (faster and slower groups). Foot-ball contacts cadence, centre of mass (CoM), ranges of motion (RoM), velocity and acceleration, as well as stride length, cadence and variability were computed. Hip and knee joint RoMs were also considered. Faster players, as compared to slower players, showed a 30% higher foot-ball cadence (3.0 ± 0.1 vs. 2.3 ± 0.2 contacts · s^?1, P < 0.01); reduced CoM mediolateral (0.91 ± 0.05 vs. 1.14 ± 0.16 m, P < 0.05) and vertical (0.19 ± 0.01 vs. 0.25 ± 0.03 m, P < 0.05) RoMs; higher right stride cadence (+20%, P < 0.05) with lower variability (P < 0.05); reduced hip and knee flexion RoMs (P < 0.05). In conclusion, faster players are able to run with the ball through a shorter path in a more economical way. To effectively develop dribbling skill, coaches are encouraged to design specific practices where high stride frequency and narrow run trajectories are required.     

社区居家养老服务中心体育服务需求与供给研究——以武汉市为例

运用文献资料法、问卷调查法、数理统计法等,对武汉市社区居家养老服务中心的体育服务需求与供给现状进行研究。研究表明:社区老年人有较强的参与体育活动愿望,且参与体育活动在时段选择、时间长度、时间频率、活动强度等方面有着自身的规律;而养老服务中心的体育服务在场地设施、健身指导、信息宣传等方面与老年人的需求存在差距。建议:社会转型期的社区居家养老服务中的体育服务应做到体育服务供给主体多元化、体育服务内容多样化、体育服务人员专业化、体育志愿服务常态化。     

大众文化的兴起

“大众文化”作为一个20世纪新兴的文化现象,有着独特的内涵和特征,对于这一文化现象兴起的原因历来众说纷纭,大众文化兴起的原因主要表现为：（1）科技时代机械复制技术的成果;（2）大众精神层面需求的滋生推进了这一文化现象的产生与发展;（3）产业利润的驱使也推动了这一现象的产生。     

对成人心血管机能健康评价的探讨

对德州市成人的心血管机能指标：心率、收缩压、舒张压、台阶指数进行分析与评价，结果为下等和差等、研究认为健康意识差、膳食结构不合理、运动习惯差、缺少体育文化氛围是造成现状的重要原因，针对群体状况提出“自我感觉练习法”和几项对策与建议，以指导健身练习。     

物理化学实验大循环教学方法初探

探讨了在物理化学实验大循环实验中如何充分利用有限的课堂时间和实验设备完成实验要求的教学方法，这些方法也适用于其他学科的循环实验。     

高等教育大众化质量问题浅探

中国高等教育大众化的临近使得高等教育的质量问题日益成为人们关注的热点。本文主要从微观即学校内部的角度来分析影响高等教育质量的原因并从五个方面提出了解决办法。