共查询到20条相似文献，搜索用时 171 毫秒
1.
运用信息技术和理论分析的方法对琼斯的“屈蹬式”短跑技术进行了生理学分析,对短跑的部分经典观点提出了质疑.研究指出:膝关节保持较小角度(150o—155o)就保证了屈膝肌较大的拉力角和拉力矩,在此角度肌肉能产生最大张力,从而能获得较大的位移速度和步频. 相似文献
2.
通过对36名女大学生24式简化太极拳练习前后下肢关节运动幅度的测量和研究发现，简化太极拳锻炼能够明显增加人体下肢关节的运动幅度；提示坚持简化太极拳锻炼，能改善下肢各主要关节的活动范围，尤其是增大髋关节和膝关节的运动幅度，有效地提高下肢关节肌肉、韧带的伸展性和柔韧性，对预防下肢关节运动损伤的发生起到积极作用。 相似文献
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潘康 《中学物理教学参考》2009,(1):52-53
在中学物理力学中常会遇到杠杆最省力的力臂判断问题,亦即力臂何时最大的问题．因部分学生对杠杆力臂概念本质的认识模糊,故对不同类型杠杆在实际使用中最省力的力臂判断问题便感到困难,时常出现一些错误;例如一些学生往往认为取杠杆长度作为力臂时力臂最大,所施动力最小亦即最省力,其实这种认识是片面的、不正确的． 相似文献
5.
通过用电动跑台进行渐增负荷运动试验，对24名男大学生（普通系、体育系各12名）进行运动心肺功能的测试．结果表明：体育系男生的最大吸氧量及其相对值、最大通气量、心率、氧脉搏及无氧阈时的吸氧量百分比等指标均比普通系男生高，且两者差异显著． 相似文献
6.
力和力矩是两个不同的概念，应加以区别使用；肌肉工作时定点的确定要以躯体支撑点为基本参考点，肌肉做静力性工作时是双固定状态；肌肉拉力线应用射线来标示；要根据具体情况作具体分析，不能简单地以动点向定点的连线标示，影响肌肉最大力量的解剖学因素是该肌肉内可能形成的最大横桥数目和肌肉收缩时的初长度，神经调节、肌拉力角、肌收缩矩均不是影响肌肉最大比力的解剖学因素． 相似文献
7.
“最大面积”模型及其训练学意义 总被引：1，自引：1，他引：0
徐翼 《内江师范学院学报》2008,23(6):91-94
将“木桶理论”体积表达式简化为面积表达式,进而提出了限制运动成绩的“双瓶颈点”概念、板块权重值概念,以及反映项目对因素板块相对需求程度的伸缩系数K值概念,提出了建立刻画运动素质与能力关系的“最大面积”模型的构想,新增了各板块位置的自动排序功能,较好地从整体角度对运动成绩变化进行动态的综合量化评价,为确定运动训练方向提供决策参考． 相似文献
8.
众所周知，几何画板软件的精髓在于展现运动变化的数学对象，通过探究不断变化的数学过程，可以发现不变的数学事实．所以在数学教学中，利用几何画板软件做课件时，经常需要一种可以自由变化的量，让其参与各种计算和变换，控制动态图形、建立动态的函数解析式等等，类似于数学中的变量，我们可以称其为参数．在该软件4．0和之前的各版本中，要建立一个参数，通常的做法是：先在直角坐标系中做一条定直线，然后取该直线上的一点，度量其坐标，分离其横坐标或纵坐标．点在直线上运动时，其坐标值也做相应变化，从而可以用这个坐标值作为一个参数．这个过程较为繁琐，操作起来多有不便．[第一段] 相似文献
9.
物理是以实验为基础的学科，信息技术对常规的物理实验有什么帮助?通过电脑，网络、多媒体技术，可使所有的实验都达到最好的可见度；使某些实验打破时间限制．便于保存和反复演示．更清楚地把同类事物的运动变化或不同事物的运动变化的过程、测量的结果等摆在一起进行对比总结。 相似文献
10.
郭艳利 《洛阳师范学院学报》2014,(8):94-96
毽球运动具有负荷小、易坚持的特点,适合锻炼膝关节周围肌肉、韧带.以骨性关节炎、膝关节创伤后造成的慢性疼痛患者为研究对象,让受试者进行长期毽球运动锻炼,结果观察到膝关节疼痛患者在运动后,疼痛症状减轻,膝关节轻松有力,达到了治疗关节疼痛的效果. 相似文献
11.
王树金 《鞍山师范学院学报》2004,6(6):97-99
采用运动录像和解析法,对黑龙江省体工队青年男篮和哈尔滨体育学院男篮的上步纵跳的起跳动作进行研究分析,结果表明运动员膝关节的缓冲能力、踝关节的蹬伸能力及髋、膝、踝关节合理的用力顺序与上步纵跳成绩密切相关. 相似文献
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采用文献资料法、专家访谈法以及等速肌力测试法,对不同水平的古典式摔跤运动员膝关节最大力量、快速力量、力量耐力及平均峰力矩等指标进行对比分析.结果发现:所选取一级运动员在膝关节伸、屈肌群最大力量、快速力量及力量耐力上均优于二级运动员;古典式摔跤运动员膝关节屈、伸肌群平均峰力矩之比均随速度加快而增大,且膝关节屈肌力量增长幅度高于其他项目运动员.建议在今后训练中应注重结合专项技术动作发展膝关节的快速蹬伸能力,努力提高膝关节伸、屈肌群的最大力量、快速力量及力量耐力水平,并注意膝关节伸、屈肌群力量的均衡发展. 相似文献
13.
Hai Zhou Dong-mei Wang Tao-ran Liu Xiang-sen Zeng Cheng-tao Wang 《Journal of Zhejiang University. Science. B》2012,13(10):831-838
Objective: The purpose of this study was to measure the kinematics of the lower limbs of Chinese people during normal kneeling activity, as such data could be valuable in designing joint prosthesis and arthroplasty that meet the needs of Chinese citizens’ daily activities. Methods: Thirty young and twenty elderly Chinese participants with no personal history of joint diseases were recruited, and matched by age (average age: 23.8 years for the young group, 60.8 years for the elderly group). Each participant performed six trials during which three-dimensional (3D) kinematics data were collected and the means of the 3D angles of the ankle, knee, and hip joints of two groups were calculated. Results: There were no obvious differences between the two groups in the knee and ankle joints. The mean range of knee flexion was 139.6° for the young group and 140.9° for the elderly group. The mean range of ankle flexion was 35.7° for the young group and 37.6° for the elderly group. The maximal eccentric flexion at the hip joint was 67.5° for the young group compared to 100.5° for the elderly group. Conclusions: The elderly uses more hip flexion angles than the young when assuming the kneeling posture. The ranges of motion obtained during kneeling activity are greater than the reported mean ranges of motion achieved following joint arthroplasty. The data could be valuable in establishing criteria for lower limb prosthetics and rehabilitation protocol for the Chinese population. 相似文献
14.
Reduction of roll and pitch motions is critical in improving the safety and operability of a ship. In this paper, a predictive controller for a ship equipped with two pairs of active fins is proposed for joint pitch-roll stabilization. The proposed controller is developed on the basis of ship motion and hydrodynamic force prediction (SMHFP). The SMHFP controller consists of a short-term predictor, a force estimator, and a fin angle allocator. The short-term predictor adopts an autoregressive (AR) approach and serves to forecast ship motions. Then, predicted ship motions are used in an external hydrodynamic force estimator to evaluate the expected stabilizing forces. Finally, the optimal attack angles for active fins are allocated based on external hydrodynamic forces forecasts. The control system of the stabilizing fins and SMHFP controller is integrated into the sea-keeping program. The program was developed based on a weakly nonlinear 2.5D method, which shows better efficiency and accuracy compared with conventional 2D and 3D methods. To evaluate the performance of the proposed controller, numerical simulations of the joint pitch-roll stabilization under various sea states were investigated on a ship model. The results suggest that the SMHFP controller shows satisfactory performance in reducing pitch and roll motions simultaneously. 相似文献
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F. Richard Clemente Philip A. Fabrizio Michael Shumaker 《Anatomical sciences education》2009,2(1):41-46
The knee is one of the most frequently injured joints of the human body with injuries affecting the general population and the athletic population of many age groups. Dissection procedures for the knee joint typically do not allow unobstructed visualization of the anterior cruciate or posterior cruciate ligaments without sacrificing the collateral ligaments. In many cases, the relationships of the intraarticular structures are lost as dissection systematically removes superficial structures to gain access to deeper structures. The authors present an alternative technique for dissection of the human knee joint that allows maximal visualization of intraarticular structures such as the cruciate ligaments and menisci with minimal disturbance to the tibial and fibular collateral ligaments, thus preserving the relationships of the ligamentous and intraarticular structures. Anat Sci Ed 2:41–46, 2009. © 2009 American Association of Anatomists. 相似文献
16.
广东省高校篮球运动员运动损伤的分析与预防——以膝关节为例 总被引：3，自引：0，他引：3
张利超 《新乡师范高等专科学校学报》2006,20(5):142-144
篮球运动中经常会出现运动损伤,其中膝关节损伤极为常见。它一般发生在突发性的变向动作中,如急停、急起、起跳和外力冲撞等。通过运用文献资料法、问卷调查法、专家访问与现场观察座谈相结合的方法,调查并分析了广东省高校大学生篮球运动员膝关节损伤发生的原因及致伤的危险因素,提出了损伤预防的具体措施。 相似文献
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To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial compression load and low reversed cyclic loading,which imitated low to moderate earthquake force.The seismic behavior of specially shaped column joints with X-shaped reinforcement in terms of bearing capacity,displacement,ductility,hysteretic curve,stiffness degradation and energy dissipation was studied and compared to that without Xshaped reinforcement in joint core region.With the damage estimation model,the accumulated damage was analyzed.The shearing capacity formula of specially shaped column joints reinforced by X-shaped reinforcement was proposed with a simple form.The test results show that X-shaped reinforcement is an effective measure for improving the seismic behavior of specially shaped column joints including deformation behavior,ductility and hysteretic characteristic.All specimens were damaged with gradual stiffness degeneration.In addition,X-shaped reinforcement in the joint core region is an effective way to lighten the degree of cumulated damage.The good seismic performance obtained from the specially shaped column joint with X-shaped reinforcement can be used in engineering applications.The test value is higher than the calculated value,which indicates that the formula is safe for the design of specially shaped column joints. 相似文献
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In order to evaluate the seismic behavior of confined RC column-composite beam joints, five interior joints were tested under low cyclic reversed load. The weakening extent of flanges, the number of studs, and whether to reinforce weakened flanges were used as parameters in designing these five joints. Failure characteristics, hysteretic curves, skeleton curves, ductility, energy dissipation, strength degradation, and stiffness degradation were analyzed. The test results revealed that the steel beam flanges in the joints were equivalent to the tie rod. Weakened flanges resulted in poor seismic behavior; however, the seismic behavior could be improved by increasing studs and reinforcing weakened flanges. The joint steel plate hoops, equivalent to stirrups, did not yield when the maximum load was reached, but yielded when the failure load was reached for the joints with shear failure. Increasing stud-type joints and reinforcing flange-type joints ensured good seismic behavior and met project requirements. Based on the experimental results, the failure mechanism of the joints was discussed, and the shear capacity equations of the joints was presented. 相似文献
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伴发ATTR型淀粉样沉积的骨关节炎患者的临床和生物学特征分析(英文)简 总被引：1，自引：0，他引：1
Ya-jun GU Peng GE Yun MU Jin-hai LU Fang ZHENG Xu-guo SUN 《Journal of Zhejiang University. Science. B》2014,15(1):92-99
Objective： Our aim was to investigate clinical and laboratory characteristics of osteoarthritic patients who had amyloid deposition in their knee joints. Methods： Synovial membranes were obtained from 36 patients with knee osteoarthritis （OA） who underwent joint replacement surgery. From this sample, the diagnosis of amyloid was deter- mined by Congo red staining, which demonstrated apple-green birefringence under a polarized microscope. All syn- ovial membranes were immunohistochemically characterized for the expressions of amyloid immunoglobulin light chain （AL-K and AL-,k）, serum amyloid-A （SAA）, amyloidogenic transthyretin （ATTR）, and amyloidogenic 152- microglobulin （A152M）. Matrix-assisted laser desorption-ionizaton/time of flight mass spectrometry （MALDI-TOF MS） was used to analyze transthyretin （TTR） isoforms in the serum of each patient. Results： Nine cases （25%） were found to be amyloid-positive. Immunohistochemicaliy, eight cases （88.9%） had ATTR deposition, and one sample （11.1%） was shown to be AL-K-positive. MALDI-TOF MS identified that the TTR in the serum of the patients was unmodified wild-type TTR, TTR-Cys-S-S-Cys, and TTR-Cys-S-S-CysGly. The age at surgery and the disease duration were sig- nificantly higher in the ATTR-positive group than in the ATTR-negative group. Knee score and function score were significantly lower in the ATTR-positive group than in the ATTR-negative group. Conclusions： Amyloid deposition in synovial membranes of OA patients was found to be ATTR and AL-K. TTR in the serum of the patients was unmodified wild-type TTR together with two isoforms. The high age at surgery, long disease duration, and a deteriorated knee function were associated with ATTR amyloid deposition in the osteoarthritic knee joints. 相似文献
20.
主从式远程康复机器人系统中力反馈的实现 总被引：1，自引：0，他引：1
设计了一种力觉辅助主从式远程康复训练机器人系统,该系统由主机械臂和从机械臂构成,二者通过Internet网络相连.治疗师在医院操纵主机械臂,远地从机械臂跟踪治疗师的运动,可以使患者在家或社区康复中心进行康复训练.从机械臂及其控制器用于引导患肢关节进行安全准确地伸展和运动.主机械臂及其控制器用于远程控制和监测患者的训练过程,并对输出数据进行分析,评估训练效果.基于二端口理论和电路等小阻抗模型,设计了力反馈-位置型的控制结构来实现力反馈,使治疗师可以及时感知到患者训练过程中与机械臂的交互力.在此基础上,建立了一套单自由度远程康复训练机器人系统,对一名健康男性进行了实验研究,结果表明治疗师可以通过操纵主机械臂引导实验对象训练并感受到实验对象与从机器人的交互力信息.与传统的康复方法相比,该方式无论对于医生和患者都更为经济方便. 相似文献