对老年人骨矿含量、体成分和肌力的特征研究   总被引：9，自引：1，他引：8  

池建  张一民  李果 《北京体育大学学报》1997,(3)

选取北京市５５岁以上老年人８６名进行研究，结果发现５５岁以上老年人骨矿含量、体成分和最大肌力存在明显的性别差异。骨矿含量随着年龄增加而逐年降低，女性下降的幅度明显高于男性。骨矿含量与体脂百分比呈明显的负相关，与体重，身体密度、瘦体重和最大肌力呈正相关，与肌肉耐力无明显的关系。  相似文献   

教育投资效益流失与教育成本补偿     

谢秀英 《陕西师范大学学报(哲学社会科学版)》2004,33(5):119-123

当前,在我国东西部发展严重不平衡,劳动力市场严重分割,市场经济份额越来越大,劳动力流动限制越来越少的条件下,我国劳动力的流动基本上呈现出一种单向流动的特点,即从农村流向城市,从西部流向东部。这种流动态势造成了西部及广大农村地区教育投资效益的流失,拉大了城乡之间和东西部之间的差距,所以必须给这些地区以成本补偿。  相似文献   

对现代标枪"沿纵轴用力"提法的新探讨   总被引：2，自引：2，他引：0  

王平 《武汉体育学院学报》2004,38(6):102-104

多年来，包括中国在内的世界许多国家的标枪训练专家均认为在标枪训练的过程中必须遵循“沿纵轴用力”这一个必要条件；不论是在模仿训练还是实际训练中，这个观念从未改变。但是，笔结合多年的标枪训练经验，通过研究认为，在标枪训练中不能“沿纵轴用力”同时也不可能“沿纵轴用力”。  相似文献   

羽毛球正手发球运用"发力法"教学的实验研究     

李明川 《体育科技》2007,28(1):84-86

通过对羽毛球正手发球运用“发力法”教学进行实验研究,结果表明,“发力法”教学与常规教学相比,能有效提高发球质量,达到增强学习兴趣及提高课堂教学效果的目的。  相似文献   

划艇运动力学参数检测与分析   总被引：1，自引：0，他引：1  

曹春梅  王春财  季林红  王子羲  陈小平 《体育科学》2007,27(2):86-89

研制了一种集划桨力、划桨过程中桨的偏转角度、艇的俯仰角度和倾覆角度、艇速等多个运动力学参数为一体的新型划艇测试评价系统，实现了对这些参数的同步采集。系统通过传感器（力传感器、角度传感器和速度传感器）将采集到的数据无线传输至计算机，利用自行开发研制的软件系统，教练员可以实时地掌握运动员划船过程中的运动状态。整个系统的重量比较轻，并且数据的主要传输采用无线形式，既保证了教练员实时的了解以往单凭眼睛观测和经验判断而很难得到的一些划桨技术细节信息，同时不会对运动员的正常划船技术动作的产生过多的干扰。  相似文献   

基于结构方程的林木生物质能源产业链外部驱动力研究   总被引：1，自引：0，他引：1  

米锋  潘文婧 《科技管理研究》2015,(12)

基于产业链演化过程,引入PEST理论,运用结构方程模型探讨林木生物质能源产业链的外部驱动力及其影响程度。结果表明:现阶段产业政策和行业技术是影响林木生物质能源产业链扩展的主要驱动力,区域环境负荷在一定程度上对产业链的扩展产生正向影响,产业需求的拉动效应还未突显。在深入分析林木生物质能源产业链外部驱动力的基础上,为如何促进该产业发展提出相应的政策建议。  相似文献   

新经济环境下技术创新驱动与品牌关系驱动影响力对比研究     

唐小飞  成立  王春国  鲁平俊 《科研管理》2015,36(11):176-183

受中国传统文化的影响和关系营销在世界范围内的兴起,品牌关系营销作为中国商业市场的基础变量的地位在全社会形成共识。因此,通过品牌关系驱动顾客忠诚和品牌资产成为客户关系管理和品牌资产管理的基本逻辑与理性认知。然而,随着新一轮科技革命与产业变革的孕育兴起,品牌关系驱动能否成功应对技术创新驱动对品牌关系情感与顾客购买意愿的冲击?品牌资产的基本理论模型是否还能有效地指导新兴市场的商业实践,抑或需要重构?这些问题值得深入探究。本文以手机品牌消费者为样本,研究发现:表性特征层面,消费者逻辑仍遵循"品牌原型—品牌关系情感—购买意愿"的发展路径。本质特征层面,消费者逻辑受到外力的驱动发生改变,且与品牌关系驱动相比,技术创新驱动所发挥的调节作用更大。研究结论在一定程度上颠覆了传统的关系营销理论模型,对企业在新经济环境下的营销战略具有重要启示和指导意义。  相似文献   

创新是发展的根本动力     

冯之浚  刘燕华  方新  穆荣平  张伟 《科研管理》2015,36(11):1-10

创新是一个复杂的价值创造过程,是经济发展的决定性力量。创新驱动发展涉及现代化建设的方方面面,包括科学技术创新、商业模式创新、制度创新、管理创新和社会创新以及人才培养机制创新。为实现创新驱动发展,需要完善国家创新生态系统,加速政府职能转变,着力营造良好的创新制度文化环境,激发创新主体的创新活力,强化创新基础条件平台建设,弘扬中华民族的创新文化和创新精神,形成全社会关心创新、参与创新的良好发展局面,加快建设创新型国家和全面建成小康社会。  相似文献   

Perform kicking with or without jumping: joint coordination and kinetic differences between Taekwondo back kicks and jumping back kicks     

Kuangyou B. Cheng  Ying-Hsun Wang  Shih-Yu Kuo  Kuan-Mao Wang  Yi-Chang Huang 《Journal of sports sciences》2015,33(15):1614-1621

We investigated joint coordination differences between Taekwondo back kicks and jumping back kicks, and how jumping (in performing the latter) would alter engaging ground reaction forces (GRF) in executing kicking. Ten skilful athletes volunteered to perform both kinds of kicking within the shortest time for three successful trials. Three high-speed cameras and two force platforms were used for data collection, and the trial with the shortest execution time was selected for analysis. Movements were divided into the rotation and attack phases. With comparable execution time and maximum joint linear/angular speeds, back kicks and jumping back kicks differ mainly in larger GRF in the latter, and in greater target acceleration in the former probably because the support leg prevented athletes’ rebounding after impact. In addition, more prominent antiphase and in-phase coordination between the shoulder segment and knee joint, and elongated rotation phase were found in jumping back kicks. Larger GRF values in jumping back kicks were generated for jump take-off rather than for a more powerful attack. In back kicks although the support leg remained ground contact, greatly decreased GRF in the attack phase suggested that the support leg mainly served as a rotation axis.  相似文献   

Validation of two accelerometers to determine mechanical loading of physical activities in children     

Ursina Meyer  Dominique Ernst  Silvia Schott  Claudia Riera  Jan Hattendorf  Jacqueline Romkes 《Journal of sports sciences》2015,33(16):1702-1709

The purpose of this study was to assess the validity of accelerometers using force plates (i.e., ground reaction force (GRF)) during the performance of different tasks of daily physical activity in children. Thirteen children (10.1 (range 5.4–15.7) years, 3 girls) wore two accelerometers (ActiGraph GT3X+ (ACT), GENEA (GEN)) at the hip that provide raw acceleration signals at 100 Hz. Participants completed different tasks (walking, jogging, running, landings from boxes of different height, rope skipping, dancing) on a force plate. GRF was collected for one step per trial (10 trials) for ambulatory movements and for all landings (10 trials), rope skips and dance procedures. Accelerometer outputs as peak loading (g) per activity were averaged. ANOVA, correlation analyses and Bland–Altman plots were computed to determine validity of accelerometers using GRF. There was a main effect of task with increasing acceleration values in tasks with increasing locomotion speed and landing height (P < 0.001). Data from ACT and GEN correlated with GRF (r = 0.90 and 0.89, respectively) and between each other (r = 0.98), but both accelerometers consistently overestimated GRF. The new generation of accelerometer models that allow raw signal detection are reasonably accurate to measure impact loading of bone in children, although they systematically overestimate GRF.  相似文献