女子三级跳远三跳起跳技术的生物力学评价   总被引：10，自引：0，他引：10  

李建设  胡宗元  贺辉 《体育科学》1992,(2)

本文建立了一个适合于评价三级跳远技术水平的系统评价框图,并根据这个框图设计了一个决定三级跳远效果的生物力学参数系统。利用这个系统分析和评价了当代女子三级跳远亚洲纪录保持者李惠荣的三级跳远技术(所用技术影片是在1989年全国田径冠军赛上用LOCAM型高速摄影机以每秒100幅的速度扫描拍摄的),并通过与男子三级跳远运动员的技术特征的比较,找出了其技术上的优势和不足,并就如何改进和完善其三跳技术提出了一份系统而直观的研究报告。同时为女子三级跳远的再研究提供了可供借鉴的研究方法。  相似文献   

4×100米接力跑的技战术分析   总被引：1，自引：0，他引：1  

丁新兴 《渭南师范学院学报》2003,18(2):77-78

影响4×100米接力跑成绩的主要因素有:短跑能力、高速跑进中的传接棒技术、合理的棒次安排等.教学中应以此为重点  相似文献   

PLC在电动机控制系统中的应用     

夏勇 《郧阳师范高等专科学校学报》2003,23(3):47-49

介绍了PLC与一台自耦变压器组成的启动设备在对多台电动机启动和控制电路中的应用，用一台自耦变压器不同时启动多台异步电动机的控制方法。  相似文献   

The effect of different foot and hand set-up positions on backstroke start performance     

Karla de Jesus  Kelly de Jesus  J. Arturo Abraldes  Luis Mourão  Márcio Borgonovo-Santos  Alexandre I. A. Medeiros 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(4):481-496

Foot and hand set-up position effects were analysed on backstroke start performance. Ten swimmers randomly completed 27 starts grouped in trials (n = 3) of each variation, changing foot (totally immersed, partially and totally emerged) and hand (lowest, highest horizontal and vertical) positioning. Fifteen cameras recorded kinematics, and four force plates collected hands and feet kinetics. Standardised mean difference and 95% confidence intervals were used. Variations with feet immersed have shown lower vertical centre of mass (CM) set-up position (0.16 m), vertical impulse exerted at the hands, horizontal and vertical impulse exerted at the feet (0.28, 0.41, 0.16 N/BW.s, respectively) than feet emerged with hands horizontal and vertically positioned. Most variations with feet partially emerged exhibited higher and lesser vertical impulse exerted at hands than feet immersed and emerged (e.g. vertical handgrip, 0.13, 0.15 N/BW.s, respectively). Variation with feet emerged and hands on the lowest horizontal handgrip depicted shorter horizontal (0.23, 0.26 m) and vertical CM positioning at flight (0.16, 0.15 m) than the highest horizontal and vertical handgrip, respectively. Start variations have not affected 15-m time. Variations with feet partially or totally emerged depicted advantages, but focusing on the entry and underwater biomechanics is relevant for a shorter start time.  相似文献   

Are the new starting block facilities beneficial for backstroke start performance?     

Karla de Jesus  Kelly de Jesus  J. Arturo Abraldes  Alexandre Igor Araripe Medeiros  Ricardo J. Fernandes  João Paulo Vilas-Boas 《Journal of sports sciences》2016,34(9):871-877

We aimed to analyse the handgrip positioning and the wedge effects on the backstroke start performance and technique. Ten swimmers completed randomly eight 15 m backstroke starts (four with hands on highest horizontal and four on vertical handgrip) performed with and without wedge. One surface and one underwater camera recorded kinematic data. Standardised mean difference (SMD) and 95% confidence intervals (CI) were used. Handgrip positioning did not affect kinematics with and without wedge use. Handgrips horizontally positioned and feet over wedge displayed greater knee angular velocity than without it (SMD = ?0.82; 95% CI: ?1.56, ?0.08). Hands vertically positioned and feet over wedge presented greater take-off angle (SMD = ?0.81; 95% CI: ?1.55, ?0.07), centre of mass (CM) vertical positioning at first water contact (SMD = ?0.97; 95% CI: ?1.87, ?0.07) and CM vertical velocity at CM immersion (SMD = 1.03; 95% CI: 0.08, 1.98) when comparing without wedge use. Swimmers extended the hip previous to the knee and ankle joints, except for the variant with hands vertically positioned without wedge (SMD = 0.75; 95% CI: ?0.03, 1.53). Swimmers should preserve biomechanical advantages achieved during flight with variant with hands vertically positioned and wedge throughout entry and underwater phase.  相似文献   

Kinematic and kinetic analyses of the toes in dance movements     

Danielle N. Jarvis  Kornelia Kulig 《Journal of sports sciences》2016,34(17):1612-1618

Due to the significant amount of time dancers spend on the forefoot, loads on the metatarsophalangeal joints are likely high, yet vary between dance movements. The purpose of this study was to compare joint motion and net joint moments at the metatarsophalangeal joints during three different dance movements ranging in demands at the foot and ankle joints. Ten healthy, female dancers (27.6 ± 3.2 years; 56.3 ± 6.9 kg; 1.6 ± 0.1 m) with an average 21.7 ± 4.9 years of dance training performed relevés (rising up onto the toes), sautés (vertical bipedal jumps), and saut de chat leaps (split jumps involving both vertical and horizontal components). Metatarsophalangeal joint kinematics and kinetics in the sagittal plane were calculated. Total excursion and peak net joint moments during rising or push-off were compared between the three dance movements. Greater extension of the metatarsophalangeal joints was seen during relevés compared to sautés or saut de chat leaps, and the largest metatarsophalangeal net joint moments were seen during saut de chat leaps. The metatarsophalangeal joints frequently and repetitively manage external loads and substantial metatarsophalangeal extension during these three dance movements, which may contribute to the high rate of foot and ankle injuries in dancers.  相似文献   

螺纹编程指令介绍及多头螺纹的编程技巧     

陈银清  冯旭强 《茂名学院学报》2008,18(1):32-34

详细介绍了在数控车床上加工螺纹的编程指令G32、G92、G76的具体含义,并分析多头螺纹的加工原理,通过实例说明单头螺纹和多头螺纹的编程方法,说明加工多头螺纹主要是需在Z轴方向上改变起点位置来实现分度.  相似文献   

Literacy and language outcomes of comprehensive and developmental-constructivist approaches to early childhood education: A systematic review     

《Educational Research Review》2016

This systematic review of research on early childhood programs seeks to identify effective approaches capable of improving literacy and language outcomes for preschoolers. It applies consistent standards to determine the strength of evidence supporting a variety of approaches, which fell into two main categories: comprehensive approaches, which include phonemic awareness, phonics, and other skills along with child-initiated activities, and developmental-constructivist approaches that focus on child-initiated activities with little direct teaching of early literacy skills. Inclusion criteria included use of randomized or matched control groups, evidence of initial equality, a minimum study duration of 12 weeks, and valid measures of literacy and language. Thirty-two studies evaluating 22 programs found that comprehensive early childhood programs that have a balance of skill-focused and child-initiated activities programs had significant evidence of positive literacy and language outcomes at the end of preschool and on kindergarten follow-up measures. Effects were smaller and not statistically significant for developmental-constructivist programs.  相似文献   

普通高等院校高水平跳跃运动员实施助力训练的研究     

张本春 《北京体育大学学报》2007,30(4):560-561

为提高跳跃运动员成绩,提高训练的实效性,训练中针对运动成绩出现的"高原现象",依据田径跳跃项目的训练特点,制定一些助力训练法.以普通高等院校高水平运动员为实验对象,在实验训练中尝试了这些助力训练法,发现对提高运动员的专项成绩起到了积极作用.  相似文献   

公共教育学教学逻辑起点的三维视角辨析     

雷江华 《河北师范大学学报(教育科学版)》2010,12(11)

公共教育学教学的逻辑起点主要存有师范生、教师、人三个维度,据此出发构建的教 育学体系分别是师范教育学体系、教师教育学体系、大众教育学体系.师范教育学体系迎合 了教师职前教育的需要,但忽略了教师职后教育的需求.教师教育学体系有效地将教师的职 前教育与职后教育要求结合起来,但仍然未能拓展教育在社会发展中的作用.大众教育学体 系则从所有人在社会不同场所中的教育角色出发树立"人人是教育者"的理念,以实现构建和谐社会的宏伟目标.  相似文献