竞技健美操直角支撑转体720°的生物力学分析

实验以三维高速摄像以及肌电测试为手段,通过三维运动学解析及肌电图分析,获得我国优秀健美操运动员完成直角支撑转体720度的运动生物力学参数,明确该难度动作的技术结构、特征,发现运动员完成动作过程中不合理的动作技术,进而为运动员的训练提出改进的参考性意见,争取使我国健美操选手在国际比赛中高质量完成这个难度动作提供理论和实践依据.     

不同走步姿态的运动生物力学对比分析

通过录像、测力台和八通道无线表面肌电仪同步的方法,对9名受试者进行不同走步姿态(内八走、正常走、外八走)的测试,运用录像解析系统、三维测力平台软件(版本V5.2)和肌电数据处理软件获得运动学、动力学和肌电学数据。结果显示:(1)外八X方向的力值是最大的,正常走在Y方向和Z方向的力值是最大的。(2)在正常步态中,半腱肌平均肌电的值是最大的,半腱肌的主要作用是使大腿在髋关节处旋内.对抗骨盆的扭转。内八步态中半腱肌和腓肠肌内侧平均肌电的值都比较大,导致用来对抗骨盆扭转的内回旋程度超过了骨盆扭转程度,从而形成了内八的走步姿势。外八步态中股二头肌和腓肠肌外侧平均肌电的值是最大的,使得骨盆的外回旋程度加大,从而造成了外八的走步姿势。(3)在正常步态中原动肌的积分肌电比较高,说明肌肉用力比较大,在此过程中人体给地面以较大的作用力,同时地面给人体以较大的支撑反作用力。     

对两名不同水平男子铅球选手投掷技术的生物力学分析

使用高速摄像对两名不同水平男子背向滑步推铅球选手投掷时身体环节的速度变化进行生物力学分析.结果表明,两名运动员最后用力时身体重心和胸部的速度变化存在明显区别,身体投掷一侧各环节的速度变化也有所不同.制定了推铅球最后用力身体环节速度递增系数.     

体操跳马难度动作研究

应用三维DLT方法对优秀运动员所做的跳马难度动作进行了分析,得知在起跳的时候,身体的关节角度是不同的,特别是肩的角度。踺子上板和助跑起跳上板具有很大的区别。在起跳的第一腾空中,其时间小于到最高点的时间,所以反映出快速撑马完成第一腾空。第二腾空时间最长达到平均值1.03秒,最高重心高度在2.85米,完成高难动作。在第二腾空开始的时候,增加旋转的角速度要屈臂,紧抱躯干。同时转体是表现为先慢,后快,再慢的变化。快速的助跑和达到最高的第二腾空是完成难度动作的关键。     

被动运动和电刺激对失神经大鼠股骨生物力学性能影响的研究

目的:探讨被动运动和电刺激对失神经大鼠股骨生物力学性能的影响。方法:切断大鼠坐骨神经和股神经,造成失神经支配大鼠废用性骨质疏松模型,并随机将大鼠分为假手术组、对照组(NCG)、被动运动组(PMG)、电刺激组(ESG)和被动运动 电刺激组(PMESG)5组,观察各组大鼠股骨生物力学指标的变化。结果:与假手术组比较,其余各组股骨弹性模量、极限强度、结构刚度、最大载荷、能量吸收均显著性降低(P<0.05),最大应变值显著性升高(P<0.05);与对照组比较,各组弹性模量、极限强度、结构刚度、最大载荷、能量吸收均显著性升高(P<0.05),最大应变值除被动运动组仅见降低趋势外(P>0.05),其余各组均显著性降低(P<0.05)。结论:大鼠失神经支配可引起股骨生物力学性能下降,电刺激和被动运动治疗可减缓失神经大鼠股骨生物力学性能的改变。因此,被动运动和电刺激能有效预防失神经所致的废用性骨质疏松,二者联合作用效果更佳。     

扁平足的研究进展

采用文献资料法,从扁平足的定义与分类、测检与分级、形成原因、危害及其治疗等几个方面进行了综述,为进行系统的扁平足研究提供参考。     

生物力学在青少年业余训练中正手攻球教学中的运用研究

目的：正手攻球是乒乓球技术动作中最基础、最重要的组成部分,我国乒乓球界素来就有得正手者得天下的传统技战术思想,因此正手攻球技术在青少年业余训练中的教学地位重要;方法：录像观察法、文献资料法;结果：通过14周的实验,实验组学生正手攻球的肘关节引拍结束点与随挥结束点角度分别为105．08 o、85．05 o,肩关节引拍结束点与随挥结束点角度分别为23．64 o、45．86 o。正手攻球考核数量实验组为30个,控制组为17个。结论：实验组学生的动作规范程度与击球回合数明显好于控制组学生。     

Wearable inertial sensors in swimming motion analysis: a systematic review

The use of contemporary technology is widely recognised as a key tool for enhancing competitive performance in swimming. Video analysis is traditionally used by coaches to acquire reliable biomechanical data about swimming performance; however, this approach requires a huge computational effort, thus introducing a delay in providing quantitative information. Inertial and magnetic sensors, including accelerometers, gyroscopes and magnetometers, have been recently introduced to assess the biomechanics of swimming performance. Research in this field has attracted a great deal of interest in the last decade due to the gradual improvement of the performance of sensors and the decreasing cost of miniaturised wearable devices. With the aim of describing the state of the art of current developments in this area, a systematic review of the existing methods was performed using the following databases: PubMed, ISI Web of Knowledge, IEEE Xplore, Google Scholar, Scopus and Science Direct. Twenty-seven articles published in indexed journals and conference proceedings, focusing on the biomechanical analysis of swimming by means of inertial sensors were reviewed. The articles were categorised according to sensor’s specification, anatomical sites where the sensors were attached, experimental design and applications for the analysis of swimming performance. Results indicate that inertial sensors are reliable tools for swimming biomechanical analyses.     

The effect of breast support and breast pain on upper-extremity kinematics during running: implications for females with large breasts

The relationship between inappropriate breast support and upper-extremity kinematics for female runners is unclear. The purpose of this study was to investigate the effect of breast support and breast pain on upper-extremity kinematics during running. Eleven female recreational runners with larger breasts (UK D and E cup) completed a 7 min 20 s treadmill run (2.58 m · s^?1) in a high and low breast support condition. Multi-planar breast and upper-extremity kinematic data were captured in each breast support condition by eight infrared cameras for 30 s towards the end of the run. Breast pain was rated at the end of each treadmill run using a numeric analogue scale. The high support bra reduced breast kinematics and decreased breast pain (P < 0.05). Upper-extremity kinematics did not differ between breast support conditions (P > 0.05), although some moderate positive correlations were found between thorax range of motion and breast kinematics (r = 0.54 to 0.73). Thorax and arm kinematics do not appear to be influenced by breast support level in female runners with large breasts. A high support bra that offers good multi-planar breast support is recommended for female runners with larger breasts to reduce breast pain.     

Kinematic,kinetic and EMG analysis of four front crawl flip turn techniques

This study aimed to analyse the kinematic, kinetic and electromyographic characteristics of four front crawl flip turn technique variants. The variants distinguished from each other by differences in body position (i.e. dorsal, lateral, ventral) during rolling, wall support, pushing and gliding phases. Seventeen highly trained swimmers (17.9 ± 3.2 years old) participated in interventional sessions and performed three trials of each variant, being monitored with a 3-D video system, a force platform and an electromyography (EMG) system. Studied variables: rolling time and distance, wall support time, push-off time, peak force and horizontal impulse at wall support and push-off, centre of mass horizontal velocity at the end of the push-off, gliding time, centre of mass depth, distance, average and final velocity during gliding, total turn time and electrical activity of Gastrocnemius Medialis, Tibialis Anterior, Biceps Femoris and Vastus Lateralis muscles. Depending on the variant, total turn time ranged from 2.37 ± 0.32 to 2.43 ± 0.33 s, push-off force from 1.86 ± 0.33 to 1.92 ± 0.26 BW and centre of mass velocity during gliding from 1.78 ± 0.21 to 1.94 ± 0.22 m · s^?1. The variants were not distinguishable in terms of kinematical, kinetic and EMG parameters during the rolling, wall support, pushing and gliding phases.