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21.
以海阳大秧歌中的民俗武术活动“斗秧歌”仪式为个案,运用田野调查等方法,从民俗学视角对“斗秧歌”的过程及民俗语境进行分析。认为:海阳大秧歌吸收了军事武术中的兵法谋略与民间武术技术动作,族群生存斗争与比武较技是“斗秧歌”吸收武术元素的重要动因,其逻辑形式表现为礼法约束下由“文斗”到“武斗”的递进,“文斗”体现兵法谋略智慧,武术是“武斗”的主要支撑力量。“斗秧歌”受到礼法约束,以强化乡间社会秩序的稳定,反映了中国传统社会治理中的礼法并施思想。剖析其民俗语境发现,“斗秧歌”是族群生存抗争的仪式手段、护卫生存环境的民间演习、展示个人魅力的艺术舞台,也是地域武术传播的民俗载体。武术与“斗秧歌”之间的融合互动关系,显示武术与民俗活动深厚的历史渊源及武术具有的多元价值属性。  相似文献   
22.
This study aimed to explore the strength of the force–velocity (FV) relationship of lower limb muscles and the reliability of its parameters (maximum force [F0], slope [a], maximum velocity [V0], and maximum power [P0]). Twenty-three men were tested in two different jump types (squat and countermovement jump: SJ and CMJ), performed under two different loading conditions (free weight and Smith machine: Free and Smith) with 0, 17, 30, 45, 60, and 75?kg loads. The maximum and averaged values of F and V were obtained for the FV relationship modelling. All FV relationships were strong and linear independently whether observed from the averaged across the participants (r?≥?0.98) or individual data (r?=?0.94–0.98), while their parameters were generally highly reliable (F0 [CV: 4.85%, ICC: 0.87], V0 [CV: 6.10%, ICC: 0.82], a [CV: 10.5%, ICC: 0.81], and P0 [CV: 3.5%, ICC: 0.93]). Both the strength of the FV relationships and the reliability of their parameters were significantly higher for (1) the CMJ over the SJ, (2) the Free over the Smith loading type, and (3) the maximum over the averaged F and V variables. In conclusion, although the FV relationships obtained from all the jumps tested were linear and generally highly reliable, the less appropriate choice for testing the FV relationship could be through the averaged F and V data obtained from the SJ performed either in a Free weight or in a Smith machine. Insubstantial differences exist among the other combinations tested.  相似文献   
23.
Lacrosse requires the coordinated performance of many complex skills. One of these skills is shooting on the opponents’ net using one of three techniques: overhand, sidearm or underhand. The purpose of this study was to (i) determine which technique generated the highest ball velocity and greatest shot accuracy and (ii) identify kinematic and kinetic variables that contribute to a high velocity and high accuracy shot. Twelve elite male lacrosse players participated in this study. Kinematic data were sampled at 250 Hz, while two-dimensional force plates collected ground reaction force data (1000 Hz). Statistical analysis showed significantly greater ball velocity for the sidearm technique than overhand (< 0.001) and underhand (< 0.001) techniques. No statistical difference was found for shot accuracy (P > 0.05). Kinematic and kinetic variables were not significantly correlated to shot accuracy or velocity across all shot types; however, when analysed independently, the lead foot horizontal impulse showed a negative correlation with underhand ball velocity (= 0.042). This study identifies the technique with the highest ball velocity, defines kinematic and kinetic predictors related to ball velocity and provides information to coaches and athletes concerned with improving lacrosse shot performance.  相似文献   
24.
讨论了质点组内力的功是可以改变质心动能的,以及所满足的条件.  相似文献   
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26.
The skeletal muscles and the fibrous connective tissue form an extensive, body-wide network of myofascial chains. As fascia can modify its stiffness, strain transmission along these meridians is supposable. The goal of this trial therefore was to collect pilot data for potential remote effects of lower limb stretching on cervical range of motion (ROM). Twenty-six healthy participants (30 ± 6 years) were included in the matched-pairs intervention study. One group (n = 13) performed three 30 s bouts of static stretching for the gastrocnemius and the hamstrings, respectively. An age- and sex-matched control group (CG; n = 13) remained inactive. Pre- and post-intervention, maximal cervical ROM in flexion/extension was assessed. A repeated measures ANOVA revealed systematic differences between groups (P < .05). ROM increased following stretching (143.3 ± 13.9 to 148.2 ± 14°; P < .05) but remained unchanged in the CG (144.6 ± 16.8 to 143.3 ± 16.8°; P > .05). Our data point towards existence of a strain transfer along myofascial meridians. Further randomised controlled studies on conditions, factors and magnitude of tensile transmission are warranted.  相似文献   
27.
关于卢瑟福模型中电子的运动是加速还是减速,不同文献给出不同描述,甚至是截然相反的描述.本文分别从能量和力的角度定量、定性地分析了卢瑟福模型中电子的运动情况,得出了卢瑟福模型中电子绕原子核旋转、辐射能量时作加速运动的结论.  相似文献   
28.
试析当前湖北劳动力素质结构   总被引:2,自引:0,他引:2  
近年来,湖北经济增长率结束了长时期的下降而开始出现回升,经济发展的状况对全省劳动力就业形势构成了较大影响。表现为经济结构的调整带来了就业形势的变化,并进而影响劳动力素质结构的变化。  相似文献   
29.
太阳能空间斯特林热机性能的优化分析   总被引:1,自引:0,他引:1  
建立太阳能驱动的空间斯特林热机的循环模型,应用有限时间热力学理论和太阳能集热器的辐射损失模型,研究受热阻和回热损失影响的太阳能斯特林热机循环性能,导出空间热机效率的基本优化关系,确定太阳能集热器的最佳工作温度和效率界限,讨论各种不可逆性对空间热机性能的影响,所得结论可为太阳能空间斯特林热机的优化设计提供新的理论指导。  相似文献   
30.
This study investigated the immediate effects of reducing the shoe drop (i.e. the difference between the heel and the forefoot height) on the kinematics and kinetics of the lower extremities of children tennis players performing a tennis-specific movement. Thirteen children tennis players performed a series of simulated open stance forehands wearing 3 pairs of shoes differing only in the drop: 0 (D0), 6 (D6) and the control condition of 12?mm (D12). Two embedded forceplates and a motion capture system were used to analyse the ground reaction forces and ankle and knee joint angles and moments of the leading lower limb. In D6 compared with D12, the peak impact force was reduced by 24% (p?=?.004) and the ankle was less dorsiflexed at foot strike (p?=?.037). In D0 compared with D12, the peak impact force was reduced by 17% (p?=?.049), the ankle was less dorsiflexed at foot strike (p?=?.045) and the knee was more flexed at foot strike (p?=?.007). In addition, 4 out of 13 participants (31%) presented a forefoot strike pattern for some of the trials in D0. No difference was observed across shoe conditions for the peak knee extensor moment (p?=?.658) or the peak ankle plantarflexor moment (p?=?.071). The results provide preliminary data supporting the hypothesis that for children tennis players, using a 6-mm lower shoe drop might reduce heel impact forces and thus limit potentially impact-related injuries.  相似文献   
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