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体育经纪人拥有运动员察觉不到的私人信息,运动员面临的问题是如何根据观测到的一些信息通过一套激励机制来激发经纪人为其努力工作。委托—代理激励模型正是为分析非对称信息情况下的最优合同而建立的。  相似文献
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通过对足、篮球运动技术掌握过程中肢体对侧迁移的观察,采用半径误差(Radial Error,RE)和命中率对迁移效果进行评定,找寻肢体对侧迁移不对称性的方向。结果表明,在一定阶段非优势侧向优势侧的迁移效果比较显著;非优势侧的肢体对侧迁移在一定程度上有利于两侧肢体运动技术的同利。  相似文献
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运用信息经济学原理与信贷理论对我国群众体育现状调查数据进行分析发现,信息不对称性与流动性约束是制约着我国居民体育消费行为的深层因素,提出加强消费者与经营者的消费教育,将体育消费者权益保护写入《体育法》,放宽与搞活信贷市场等建议。  相似文献
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以文化强国为背景,以中国高校体育文化为研究内容,从非对称性视角进行深入分析当前高校体育文化的现状,提出高校体育文化建设的针对性对策建议,为高校体育文化大繁荣大发展奠定一定的理论基础。  相似文献
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运用64 导脑电测试系统记录14 名乒乓球运动员和14 名普通大学生在经验相关以及经验无关图形识别时的脑电数据,计算图形识别过程中 的alpha 频段(8~13 Hz)能量变化以及theta(4~7 Hz)频段颞叶与运动前区之间的脑电相干性,以探讨乒乓球运动员大脑功能非对称性以及脑区之 间的功能耦合性。结果发现:在alpha 频段能量上,运动员对圆进行识别时左右颞叶alpha 频段能量差大于十字星,普通大学生则无差异;在对圆进行 识别时,运动员左右颞叶alpha 频段能量差值大于普通大学生;在对十字星进行识别时,alpha 频段能量无组间差异。在脑电相干性上,运动员的右半 球相干性高于左半球,普通大学生左右半球相干性无差异;在右半球相干性上,运动员高于普通大学生,而左半球相干性无组间差异;十字星形识别 过程中的脑电相干性不存在组间及半球差异。乒乓球运动员在经验相关图形识别过程中,右侧颞叶较低的激活以及右侧颞叶- 运动前区之间的高相 干性,可能表明乒乓球运动员具有良好的视觉- 空间注意技巧,在图形识别过程中更多地依赖于视觉空间加工,体现了专家大脑的神经效率加工,而 且上述特性不具有迁移性。  相似文献
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Walking is one of the preferred exercises among elderly, but could a prolonged walking increase gait variability, a risk factor for a fall in the elderly? Here we determine whether 30 min of treadmill walking increases coefficient of variation of gait in elderly. Because gait responses to exercise depend on fitness level, we included 15 sedentary and 15 active elderly. Sedentary participants preferred a lower gait speed and made smaller steps than the actives. Step length coefficient of variation decreased ~16.9% by the end of the exercise in both the groups. Stride length coefficient of variation decreased ~9% after 10 minutes of walking, and sedentary elderly showed a slightly larger step width coefficient of variation (~2%) at 10 min than active elderly. Active elderly showed higher walk ratio (step length/cadence) than sedentary in all times of walking, but the times did not differ in both the groups. In conclusion, treadmill gait kinematics differ between sedentary and active elderly, but changes over time are similar in sedentary and active elderly. As a practical implication, 30 min of walking might be a good strategy of exercise for elderly, independently of the fitness level, because it did not increase variability in step and stride kinematics, which is considered a risk of fall in this population.  相似文献
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The effects of exercise on the core musculature have not been investigated in prepubescents. The main purpose of the present study was to determine the volume and degree of asymmetry of rectus abdominis, obliques and transversus abdominis, quadratus lumborum, iliopsoas, gluteus and paravertebralis muscles in prepubescent tennis players and in untrained boys. The muscle volume was determined using magnetic resonance imaging (MRI) in 7 male prepubescent tennis players and 10 untrained controls (mean age 11.0 ± 0.8 years, Tanner 1–2). After accounting for height and body weight as covariates, the tennis players had 14–34% greater volume than the controls in all the muscles analysed (P < 0.05) except in paravertebralis, dominant quadratus lumborum and non-dominant gluteus, which had similar volumes in both groups (P = NS). Compared to controls, the tennis players displayed a greater degree of asymmetry in quadratus lumborum and rectus abdominis (3% vs. 15%, P < 0.01 and 8% vs. 17%, P = 0.06, respectively). The level of asymmetry of obliques and transversus abdominis, iliopsoas, gluteus and paravertebralis muscles was similar in both groups (P = NS). In conclusion, tennis playing at prepubertal ages induces a selective hypertrophy of the core musculature and exaggerates the degree of asymmetry of quadratus lumborum and rectus abdominis compared to untrained boys.  相似文献
9.
It is generally accepted that preadolescents have a limited capacity to develop muscle hypertrophy in response to exercise compared with older populations; however, studies are scarce and conflicting. The main aim of the present study was to assess if playing tennis is associated with the hypertrophy of dominant pectoralis muscles (PM) in professional (PRO) and in prepubescent tennis players (PRE). A secondary aim was to assess if the degree of asymmetry of PM is greater in PRO than PRE. The volume of PM of both sides was determined using magnetic resonance imaging in 8 male PRO (21.9 years), 6 male PRE (11 years, Tanner 1–2) and 12 male non-active controls (6 adults: 23.5 years; and 6 prepubescents: 10.7 years, Tanner 1–2). PRO and PRE had 15 and 30% greater volume, respectively, in the dominant than in the contralateral PM (P < .01). No significant side-to-side differences in PM volume were observed in the non-active controls (3%, P = .34 in adults and 5%, P = .17 in children). The degree of side-to-side asymmetry in PM volume was greater in PRE than in PRO (P < .05). In conclusion, tennis practice is associated with marked hypertrophy of dominant PM in tennis players, even at prepubertal age, whilst non-active age-matched control subjects display similar volumes in both sides. The larger asymmetry observed in PRE than in PRO may indicate a greater relative loading in the children or increased contralateral hypertrophy in the professionals. This study demonstrates that prepubertal children respond with marked hypertrophy to loading by tennis.  相似文献
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