中国赛艇队男轻运动员身体成分监测对训练效果的研究

通过国家赛艇队4名男轻队员冬训前后身体成分变化的研究,分析探讨中国赛艇男轻运动员最佳身体成分。结果显示,一定范围内体脂％的下降与赛艇轻量级运动员有氧耐力的提高显著相关;赛艇轻量级运动员瘦体质量的增加与否可反映力量训练的效果;本研究中,男子轻量级运动员身体成分的改变与专项测功仪能力的变化未呈显著相关性。     

Roller ski rolling resistance and its effects on elite athletes’ performance

Modern ski-treadmills allow cross-country skiers, biathletes and ski-orienteers to test their physical fitness in a laboratory environment whilst performing classical and freestyle (skating) techniques on roller skis. For elite athletes, the differences in performance between test occasions are quite small, thus emphasising the importance of knowing the roller skis’ rolling resistance in order to allow the correct comparison between the results of different test occasions. In this study, the roller skis’ rolling resistance was measured on the ski-treadmill’s surface using a roller ski rolling resistance measurement system specially produced for this purpose. The study investigated the influence of significant changes in rolling resistance on physiological variables. The results showed that during submaximal exercise, power, oxygen uptake, heart rate and blood lactate were significantly changed by different rolling resistances, while there were no significant or only small changes to cycle rate, cycle length and ratings of perceived exertion. Incremental maximal tests showed that time to exhaustion was significantly changed by different rolling resistances and this occurred without significant changes in maximal power, maximal oxygen uptake, maximal heart rate and blood lactate, and that the influence on ratings of perceived exertion were insignificant or small.     

Stress and Fracture Strength Analysis for Three-Way Pipes

l lgtroductionIt is well known that the safety of pipeline systemsfor transpofting oil or gas is very important in the oil orgas industry, and it will be a catastTophe if an accidentoccurs. Howevef, there are a lot of methods for ensuringthe safety of such pipeline systems, for instance,TopRAM program['] (TransCanada Pipeline RiskAssessment Model), IAP program['] (The integrityAssessment Program), In-line inspection tools for crackdetection in gas and liquid pipeline['l etc. The safety …     

一种画等效电路的有效办法

求复杂的混联电路的等效电阻,常常是解决电路计算问题的关键,而得出复杂的混联电路的等效电路,是求得等效电阻的必径之路,本介绍一种画等效电路的有效方法。     

间壁式传热过程中的热阻计算

通过对管道设备保温及管壳式换热器传热过程各热阻的估计分析,提出了简化计算间壁式传热过程的方法.     

小麦灌浆期叶片游离脯氨酸和可溶性蛋白质含量与抗旱性的关系

土壤干旱时 ,小麦灌浆期叶片游离脯氨酸含量增加 ,可溶性蛋白质含量减少 .抗旱性强的品种脯氨酸含量上升的幅度小于抗旱性弱的品种 ,且差异显著 ;抗旱性强的品种可溶性蛋白质含量下降的幅度小于抗旱性弱的品种     

大强度力量训练后血乳酸消除的放松性负荷强度的研究

通过实验的方法,对有机体承受大强度力量负荷之后,其血乳酸浓度的下降与有关放松跑强度之间的关系进行了探讨。结果表明,大强度力量训练后,血乳酸消除效果较好的放松跑强度不是固定的,而应随着血乳酸浓度的下降,以及放松时间的持续,逐渐下降。     

抗渗性混凝土气密性应用的研究与探讨

抗渗性混凝土是一种有着特殊性能的混凝土,除具备一般混凝土的基本性能以外,较高密实度,是其特有的性质．因而可以用于特殊部位,一般多用于地下防水性与承载性相结合的结构或构件中．作者根据多年的理论研究与实践,将抗渗性混凝土的相对较高的密实度这一特点,应用于一个崭新的领域——抗渗性混凝土在有气密性要求的混凝土粮食筒仓中的应用,并取得了良好的效果．     

钢筋砼结构表面裂缝与钢筋锈蚀关系的探讨

依据有关的试验结果,探讨了钢筋砼结构中砼表面裂缝和钢筋处裂缝宽度及钢筋锈蚀三者之间的关系,并分析了钢筋产生锈蚀的原因,认为以砼表面裂缝宽度作为钢筋锈蚀的度量标准不尽合理,控制钢筋处裂缝宽度防止钢筋的局部锈蚀较为有效     

负重振动训练对下肢快速力量的影响及其神经适应的特征

摘要：目的：研究8周负重振动训练对快速力量和下肢肌肉H反射的影响并探讨其可能的机制,以此丰富和完善负重振动训练的理论体系,并为普通人群和运动员振动力量训练方案的制定提供参考。方法：以16名男性田径专修大学生为研究对象,随机分为常规力量训练组（常规组）和振动力量训练组（振动组）。常规组完成30%1RM负重半蹲起训练,振动组附加振幅为2 mm、频率50 Hz的振动刺激,完成相同负重半蹲起训练。8周训练前后测定半蹲跳、原地纵跳和腓肠肌H反射。结果：常规组和振动组组内相对快速力量指数、原地纵跳绝对腾空高度和弹性能利用率均显著提高（P<0.05)。2组间相对快速力量指数、原地纵跳绝对腾空高度和弹性能利用率增加值均有显著性差异。组内H反射潜伏期和Hmax/Mmax减小且差异具有显著性;仅振动组H反射突触前抑制（PSI）升高且具有显著性。组间H反射潜伏期、Hmax/Mmax、PSI有显著性差异。结论：8周附加振动刺激的负重30%1RM力量训练对快速力量的提高优于相同负重的常规力量训练。8周负重振动力量训练的神经适应特征表现为H反射潜伏期、Hmax/Mmax下降和PSI的增强。