羽毛球正手发球运用"发力法"教学的实验研究

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。     

划艇运动力学参数检测与分析

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。     

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

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.     

论辅导员群体习性与职业环境的冲突——辅导员职业动力不足原因分析

年轻、专职、高学历的群体特征及特殊的求职体验造就了辅导员特殊的群体习性,即理想化、高成就动机和强烈的自我证明意识。而辅导员职业场域在高校场域中的边缘位置和场域的不成熟性,决定了多数辅导员既无法凭借本场域的资源向更高权力场域流通,又很难凭借本场域满足自身的习性要求,辅导员职业动力不足恰是上述矛盾关系的反映。     

基于推拉理论的农民工定居地选择意愿的实证研究

首先运用推拉理论从理论上分析哪些因素影响农民工定居地选择意愿,然后利用河南省汝州市187个外出打工农民样本数据,运用Logistic模型分析方法,进行实证检验。结果显示,农民工收入越高和年龄越小越倾向于在打工城市定居;外地人子女入学受歧视和老家经营的耕地面积大,倾向于回农村老家定居;打工城市为省会城市、直辖市和中心镇与对照组地级市或县城比较,在打工城市定居的意愿会下降;打工城市位于东部或是西部地区较对照组中部地区比较,在打工城市定居的意愿也会下降。最后,提出了相关建议。     

“二力平衡”教学设计

二力平衡是初中学生学习物理时第一次将运动和力联系起来的关键知识点,苏教版中学物理课程标准针对该知识点的要求是院巩固力和力的图示的知识,加深对受力问题的分析的能力,通过课堂互动以及实验探究的方式来掌握平衡概念、二力平衡条件及其应用。     

青少年足球运动员灵敏性结构模型的理论与实证研究简

近十余年来,我国足球运动员灵敏性方面与其他亚洲强队相比差距明显,如何提高灵敏性已经成为足球训练界关注的问题,提高足球运动员的敏捷性对提高足球整体竞技水平具有重要意义。本文运用了文献检索法、数理统计法、实验法等方法。指出足球运动员灵敏性结构模型在动作结构层面表现为“急停一变向一启动”,在力量结构层面表现为“制动力量一反应力量一启动力量”。通过对实验对象进行实验前后的对照,结果证明本研究所提出的足球运动员灵敏性结构模型是准确的,通过发展青少年运动员的制动力量、反应力量、启动力量能够很好的提高其灵敏性。     

浅析土家民族式摔跤—拔腰带

文章主要运用文献资料法,专家访谈法,对"拔腰带"这一土家族传统体育运动项目的发展概况、动作技术特征、开展的意义、发展的方向等方面做了详细的阐述。体现"拔腰带"的民族传统体育特色。对科学地继承与发扬少数民族传统体育、增强少数民族传统体育的活力、推进全民健身计划有重要意义。     

0Cr18Ni9不锈钢车削力试验研究

切削力是切削加工中的一种伴随现象,切削力的大小直接影响到刀具寿命、加工质量和加工效率。在分析车削力时域特征的基础上,通过0Cr18Ni9不锈钢的正交车削试验,研究了切削参数对切削力波动系数的影响规律。结果表明：动态性是车削力的基本属性,切向分力和进给分力是车削力的主要成分;切削用量三要素中,切削深度ap对进给分力波动系数Qf和切向分力波动系数Qc都有着显著的影响,两者随ap的变化趋势基本一致。     

Effect of loading on peak power of the bar,body, and system during power cleans,squats, and jump squats

Abstract

Nine males (age 24.7 ± 2.1 years, height 175.3 ± 5.5 cm, body mass 80.8 ± 7.2 kg, power clean 1-RM 97.1 ± 6.36 kg, squat 1-RM = 138.3 ± 20.9 kg) participated in this study. On day 1, the participants performed a one-repetition maximum (1-RM) in the power clean and the squat. On days 2, 3, and 4, participants performed the power clean, squat or jump squat. Loading for the power clean ranged from 30% to 90% of the participant's power clean 1-RM and loading for the squat and jump squat ranged from 0% to 90% of the participant's squat 1-RM, all at 10% increments. Peak force, velocity, and power were calculated for the bar, body, and system (bar + body) for all power clean, squat, and jump squat trials. Results indicate that peak power for the bar, body, and system is differentially affected by load and movement pattern. When using the power clean, squat or jump squat for training, the optimal load in each exercise may vary. Throwing athletes or weightlifters may be most concerned with bar power, but jumpers or sprinters may be more concerned with body or system power. Thus, the exercise type and load vary according to the desired stimulus.