花样滑冰双人滑抛跳技术特征

抛跳技术是花样滑冰双人滑技术动作中最复杂、最难掌握的一项技术动作,它也是代表花样滑冰双人滑技术水平的重要标志,因此对花样滑冰双人滑抛跳技术的探讨和研究具有重要的现实意义。运用运动生物力学、运动学解析、数理统计、文献资料等方法,对花样滑冰双人滑抛跳动作进行技术指标测试和研究。结果表明：空停时间和空中水平位移在完成动作过程中起关键作用,水平速度和腾空高度对完成高难度抛跳动作有直接影响。腾空时间应在0.9s以上,空中水平位移应在8.8m以上,以保证在空中完成转体动作,水平速度应在4.5m/s以上,水平速度是提高旋转冲力和角速度的重要保证,只有努力提高水平速度才能获得足够的旋转冲力,完成优质量、高难度、多周数的跳跃动作。     

孙太凤掷铁饼最后用力阶段运动学参数与投掷成绩的相关分析

本文采用三维录像解析法、Person相关分析等方法,以2007年全国田径锦标赛中孙太凤的5次有效投掷技术为研究对象,对孙太凤掷铁饼最后用力技术阶段的运动学参数与投掷成绩进行相关分析,结果显示：在左脚着地瞬间以及铁饼出手瞬间存在着与投掷成绩密切相关的运动学参数,同时,在最后用力的初始加速阶段、最后用力的最后加速阶段以及整个最后用力阶段也存在着与投掷成绩密切相关的运动学参数。     

如何加大器械出手速度的思考——以掷标枪为例

掷标枪是田径运动中技术比较复杂的项目之一,出手速度是影响其成绩的重要因素之一,以右手持枪为例来分析如何提高标枪的出手速度。     

静眼训练在篮球罚球技术教学中的实验研究

运用文献资料法、数理统计法等方法,通过实验研究静眼训练对篮球专修罚球教学效果的影响,研究显示：实验组与对照组的罚球命中率和技术测评差异具有显著性,静眼训练对提高罚球教学效果有着重要作用和意义,有深入研究的实际价值。     

Dynamics of the basketball shot with application to the free throw

Abstract

A completely general three-dimensional dynamic model is presented for the motion of basketball shots that may contact the rim, the backboard, the bridge between the rim and board, and possibly the board and the bridge simultaneously. Non-linear ordinary differential equations with six degrees of freedom describe the ball angular velocity and ball centre position. The model includes radial ball compliance and damping and contains five sub-models: purely gravitational flight, and ball – rim, ball – bridge, ball – board, and ball – bridge – board contact. Each contact sub-model has both slipping and non-slipping motions. Switching between the sub-models depends on the reaction force at, and velocity of, the contact point. Although the model can be used to study shots from any point on the court, we here use it to study the sets of free throw release angle, velocity, angular velocity, and lateral deviation angle that result in success (capture), as well as underhand free throws and those using an under-inflated ball. Free throw shots with larger backspin, lower inflation pressures, and underhand release conditions are shown to result in larger capture percentages.     

Effects of agonist–antagonist complex resistance training on upper body strength and power development

Abstract

The objective of this study was to examine the chronic effects on strength and power of performing complex versus traditional set training over eight weeks. Fifteen trained males were assessed for throw height, peak velocity, and peak power in the bench press throw and one-repetition maximum (1-RM) in the bench press and bench pull exercises, before and after the eight-week programme. The traditional set group performed the pulling before the pushing exercise sets, whereas the complex set group alternated pulling and pushing sets. The complex set training sessions were completed in approximately half the time. Electromyographic (EMG) activity was monitored during both test sessions in an attempt to determine if it was affected as a result of the training programme. Although there were no differences in the dependent variables between the two conditions, bench pull and bench press 1-RM increased significantly under the complex set condition and peak power increased significantly under the traditional set condition. Effect size statistics suggested that the complex set was more time-efficient than the traditional set condition with respect to development of 1-RM bench pull and bench press, peak velocity and peak power. The EMG activity was not affected. Complex set training would appear to be an effective method of exercise with respect to efficiency and strength development.     

中外男子掷标枪最后用力效果的对比分析

采用文献资料法、对比分析法,对影响中外优秀男子掷标枪运动员最后用力效果部分运动学技术指标——挥臂用力因子、左膝关节蹬伸因子和人体向前运动因子进行对比分析。希望我国教练员从中得到启发,促进我国男子标枪水平的提高。     

具有收获与投放的二维Lotka—Volterra模型的永久持续生存

研究了具有收获与投放的二维Lotka-Volterra模型的永久持续生存问题,并得到了模型永久持续生存的一些充分条件。     

双人结伴的杠杆式铁饼专门力量练习的设计及应用

水平方向上的躯干扭转力量是铁饼专项重要的基础力量 ,但提高它的练习方法很难与传统的重力性练习器械吻合。该练习是以废旧标枪和伴练者为基本练习条件 ,将伴练者施力作用于废旧标枪产生的杠杆效应作为练习负荷 ,进行各种肌肉收缩形式的躯干肌力练习。经实验和理论分析认为 ,该方法简单、有效、实用、易于推广     

我国艺术体操集体项目难度动作完成质量重要差距解析

艺术体操身体难度动作完成的质量和器械抛接到位的准确性,直接影响到成套的得分,并同时体现 了一个集体队伍的整体水平。通过录像统计,并经过分析对比,找出我国目前艺术体操集体项目与世界优秀 队伍的差距和不足。