抗负荷力量训练中附加全身振动刺激对肌力训练效果的影响

首次采用自制振动台在膝关节 1 1 0° - 1 2 0°半蹲起力量训练中 ,对运动员进行垂直方向的振动刺激。通过对振动台力量组和传统力量组的比较研究 ,发现振动台力量组能够在相对较小的负荷下有效地提高肌肉的最大力量和爆发力 ,但对肌肉耐力的作用效果不是很明显。     

两种核心力量训练方法对腹部肌群肌力变化影响的比较研究

运用文献资料调研、实验和比较分析等方法,对8名投掷专项二级运动员进行2种力量训练实验.研究表明,在振频为30～35 Hz,振幅2mm,加速度为25～30m/s的训练条件下,经过8周的振动力量训练,2组运动员峰力矩均出现一定程度的增长,尤其是Ⅱ组峰力矩增长幅度远远高于Ⅰ组,但组内检验两组均未呈现显著性差异.振动力量训练对Ⅱ组腹部肌群最大功产生了显著影响,而I组却出现了下降.在30°/s和180°/s测试条件下,Ⅱ组腹部肌群的总功增值幅度明显优于Ⅰ组,但在60°/s测试条件下,Ⅰ组腹部肌群总功的增值幅度要略高于Ⅱ组.实验后两组运动员躯干屈伸比均出现了变化,但振动力量训练对躯干屈伸比未产生明显影响.     

Exercise performance and cardiovascular health variables in 70-year-old male soccer players compared to endurance-trained,strength-trained and untrained age-matched men

Abstract

The aim was to investigate performance variables and indicators of cardiovascular health profile in elderly soccer players (SP, n = 11) compared to endurance-trained (ET, n = 8), strength-trained (ST, n = 7) and untrained (UT, n = 7) age-matched men. The 33 men aged 65–85 years underwent a testing protocol including measurements of cycle performance, maximal oxygen uptake (VO₂max) and body composition, and muscle fibre types and capillarisation were determined from m. vastus lateralis biopsy. In SP, time to exhaustion was longer (16.3 ± 2.0 min; P < 0.01) than in UT (+48%) and ST (+41%), but similar to ET (+1%). Fat percentage was lower (P < 0.05) in SP (–6.5% points) than UT but not ET and ST. Heart rate reserve was higher (P < 0.05) in SP (104 ± 16 bpm) than UT (+21 bpm) and ST (+24 bpm), but similar to ET (+2 bpm), whereas VO₂max was not significantly different in SP (30.2 ± 4.9 ml O₂ · min^?1 · kg^?1) compared to UT (+14%) and ST (+9%), but lower (P < 0.05) than ET (?22%). The number of capillaries per fibre was higher (P < 0.05) in SP than UT (53%) and ST (42%) but similar to ET. SP had less type IIx fibres than UT (?12% points). In conclusion, the exercise performance and cardiovascular health profile are markedly better for lifelong trained SP than for age-matched UT controls. Incremental exercise capacity and muscle aerobic capacity of SP are also superior to lifelong ST athletes and comparable to endurance athletes.     

游泳运动员最大吸氧量与成绩关系的研究

通过对游泳运动员水中最大吸氧量的测试，探讨游泳运动员最大吸氧量与运动成绩的关系。表明ＶＯ２ｍａｘ相对值与４００米、１５００米相关系数密切，并具依从关系。     

腘绳肌拉伤可变危险因素的筛选及对策研究

目的:对腘绳肌拉伤可变危险因素进行分析和筛选,确定主要危险因素,为损伤预防指明方向。方法:以河北省体育运动学校28名学生为研究对象,依据是否发生过单侧腘绳肌拉伤将其分为未受伤组(18人)和受伤组(10人);用Biodex System-3型等速肌力测试系统,对两组学生两膝关节进行屈伸测试,得到两组学生的腘绳肌峰力矩、腘绳肌最佳力矩角度、股四头肌峰力矩、股四头肌最佳力矩角度、股四头肌峰力矩与腘绳肌峰力矩比值(Q/H),并对所得数据进行统计分析。结果:受伤组伤侧腘绳肌峰力矩明显小于健侧(P0.05),伤侧Q/H显著大于健侧和未受伤组(P0.05)。伤侧腘绳肌最佳力矩角度大于健侧,有非常显著性差异(P0.01)。结论及建议:腘绳肌最佳力矩角度、腘绳肌峰力矩、Q/H可以作为腘绳肌拉伤的预测指标,建议选择适当的力量练习以预防腘绳肌拉伤。     

输入力矩受限空间机械臂的鲁棒自适应控制

讨论了在输入力矩受限情况下,载体位置、姿态均不受控制的漂浮基空间机械臂系统的鲁棒自适应控制问题．建立了系统的动力学方程,并借助增广变量法,成功地克服了空间机械臂系统鲁棒自适应控制方案设计的难点,设计了一种增广鲁棒自适应控制器,并应用李雅普诺夫直接方法对控制方案的渐进稳定性条件作了证明．通过系统数值仿真,证实了控制方法的有效性．     

带蕴涵算子的N元格蕴涵代数不等式的解

在格蕴涵代数中研究了带蕴涵算子的N元格蕴涵代数不等式,得到其有解的充分必要条件,同时还在b是L交既约元的情况下,找出该不等式的所有极大解,进而给出其具体解集.     

给纸机分离头扭矩分析及实验研究

针对给纸机输纸稳定性问题,对分离头凸轮分配轴扭矩分布特性进行了理论及试验研究。通过对国内典型飞达子机构进行运动学和动力学分析,得到飞达各子机构对于凸轮分配主轴的作用力及作用于分离头墙板上的反力,得到了分离头扭矩分布特性。利用开发的分离头扭矩试验平台,对分离头的扭矩波动进行了试验研究。结果表明:理论分析的扭矩分布与试验研究基本一致,从而为给纸机分离头的设计与应用提供必要的数据和优化的解决方案。     

基于螺杆启闭机的多段标定动态光电式扭矩传感器

螺杆启闭机在水电站、水库、河道渠坝等水利工程的启闭运行中起着重要的控制作用.扭矩传感器是检测螺杆启闭机荷载的关键部件.目前采用的静态扭矩式传感器,只有通过转化,才能实时检测出螺杆启闭机在运转状态下的实际负载.通过试验比较不同方案扭矩传感器的工作性能,研究采用光电滑环和多段标定技术,基于螺杆启闭机的动态光电式扭矩传感器,较好地解决了摩阻力随着启闭荷载变化时传感器无法直观显示实际荷载的关键问题,能够实时、真实、高精度地检测螺杆启闭机的运行负载,很好地满足了工程需要.     

Strong Consistency of Reliability Estimators for Multiple-Component Measuring Instruments

It is shown that the maximum likelihood estimator of the widely used omega coefficient for reliability of multicomponent measuring instruments converges almost surely to the population reliability coefficient for normal congeneric measures with uncorrelated errors as sample size increases indefinitely. This strong consistency implies convergence in probability (consistency) as well as in distribution for the omega estimator. Strong consistency is also demonstrated for the maximal reliability estimator associated with the optimal linear combination of the instrument components. The findings of this note add (i) to the recommendation to use in the general normality case the omega estimator in empirical research, (ii) to the critical literature on the popular coefficient alpha then, and (iii) to the literature on the properties of the optimal linear combination of observed measures and the maximal reliability estimator.