共查询到20条相似文献，搜索用时 109 毫秒
1.
乒乓球运动的基本技术的复杂、战术的瞬息万变以及新技术、新战术、新工具、新流派的层出不穷,是这个项目的一个显著特点。它之所以具备这个特点,是因为在竞赛中几乎运动员的每一击球都会使球产生旋转,而这些旋转则在直径3.8厘米、重仅2.5克的乒乓球的运动过程中都非常敏感地表现了出来。因此,尽量详细、准确地剖析乒乓球各种旋转,从而了解并掌握乒乓球在运动中旋转的规律性,对掌握整个乒乓球运动的规律是十分重要的。 相似文献
2.
40mm乒乓球大球，由于球体加大，球速减慢，旋转减弱，使乒乓球运动更具群盘性、广泛性，众多而普用的乒乓球人口继续为乒乓球运动、为实行全民健身纲要作贡献。如何适应和较快掌握乒乓球大球的运行与击球规律，本文在40mm乒乓球球体击球部位方面进行了探讨和研究。 相似文献
3.
旋转球的定性分析 总被引：1，自引：0，他引：1
吴焕群 《天津体育学院学报》1999,14(3):52-55
１ 乒乓球旋转的主要原因 打乒乓球时,如果力的作用线不通过球心,而和球心（Ｏ）保持一定的垂直距离（Ｌ即力臂）,这时这个力（Ｆ）变分解成一个撞击球的法向分力（Ｆ进）和一个摩擦球的切向分力（Ｆ切）,这个切向分力的主要作用就是使球产生旋转（图１、２）。因此,击球时,当力的作用线与球心保持一定的垂直距离,使力矩（Ｍ）不等于零,就是乒乓球旋转的主要原因。力矩越大,球的旋转速度就越快：Ｍ＝ＦＬ。图１ 不转球——力的作用线通过球心图２ 抽球时作用力的分解２ 乒乓球的基本旋转轴及其旋转种类 乒乓球本是无固定… 相似文献
4.
周立生 《武汉体育学院学报》1993,(3)
乒乓球基本功训练,在整个乒乓球训练体系中占有极为重要的地位。实践证明:乒乓球运动员的基本功训练,对于提高运动技术水平,攀登乒乓球运动技术高峰,延长运动寿命,都具有十分重要的意义。乒乓球运动员的基本功,是指乒乓球运动员为了达到一定运动水平所必须具备的相应的基本技能和基本体能。基本技能:主要是指技术质量、变化能力和适应能力。它包括击球的准确性、速度力量、旋转及落点;速度、力量、旋转、节奏、落点的主动变化能力;适应对方速度、力量、旋转、节奏、落点的变化能力。 相似文献
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从速度与旋转的视域对乒乓球运动发展历程进行研究,结果表明,乒乓球运动的发展历程大致经历了以下5个阶段：慢速度、弱旋转阶段;以速度主导进攻的阶段;以旋转主导进攻的阶段;速度与旋转一体化阶段;限速度、降旋转阶段。速度与旋转质量提高是未来乒乓球发展的内在需要,专项力量素质的发展是速度与旋转质量提高的基本保障,落点与弧线的精确化是速度与旋转质量提高的本质体现。 相似文献
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旋转是乒乓球项目重要制胜因素之一,在乒乓球教学训练和比赛中如何判断、制造和控制旋转一直是难点问题。目前主要通过对方接触球的动作、球标、来球落台后弹起的角度与速度的变化来判断来球旋转的变化。 相似文献
9.
在现代乒乓球技术中,增大击球力量,是对付强烈上旋的弧圈球或转与不转削球的有效方法。击球的力量。是加大球的速度和旋转的基础。而现代乒乓球运动的一切主要打法,都要借助于旋转的帮助。在战术运用上,也越来越显示出旋转的重要作用。本文从力量、旋转对回球的影响方面进行了研究。从研究实验中可以看出:力量、 相似文献
10.
少儿乒乓球训练的几点做法 总被引：2，自引：0，他引：2
乒乓球是我国的国球,对少儿进行乒乓球训练,我们的宗旨是:弘扬国球精神,培养乒坛新苗。下面介绍几点科学的训练方法,供同行参考:一、如何判断上旋、下旋击球时,作用力通过球心,则球就不旋转;反之,击球作用力不通过球心,球就旋转,各种不同的旋转球都有一定的旋转规律,只有掌握旋转规律,才能采取正确的应对措施。所以,要判断上旋、下旋,必须通过看、听才能做出正确的判断。“看”从三个方面看。一看,对方摩擦球时,拍面倾斜角度,拍触球的瞬间是摩擦球的中上部,还是中下部。球拍摩擦球的中上部为上旋,球拍摩擦球的中下部为下旋。二看,来球的飞行… 相似文献
11.
Measurements are presented of the friction force acting on a tennis ball incident obliquely on the strings of a tennis racket.
This information, when combined with measurements of ball speed and spin, reveals details of the bounce process that have
not previously been observed and also provides the first measurements of the coefficient of sliding friction between a tennis
ball and the strings of a tennis racket. At angles of incidence less than about 40° to the string plane, the ball slides across
the strings during the whole bounce period. More commonly, the ball is incident at larger angles in which case the ball slides
across the string plane for a short distance before gripping the strings. While the bottom of the ball remains at rest on
the strings, the remainder of the ball continues to rotate for a short period, after which the ball suddenly releases its
grip and the bottom of the ball slides backwards on the string plane. The bounce angle depends mainly on the angle of incidence
and the rotation speed of the incident ball. Differences in bounce angle and spin off head-clamped and hand-held rackets are
also described. 相似文献
12.
Chia-Lun Lee I-Hua Chu Bo-Jhang Lyu Wen-Dien Chang 《Journal of sports sciences》2018,36(22):2575-2582
Warm-up is an essential component for optimizing performance before an exercise session. This study investigated that the immediate effects of vibration rolling (VR), nonvibration rolling (NVR), and static stretching as a part of a warm-up regimen on the flexibility, knee joint proprioception, muscle strength, and dynamic balance of the lower extremity in young adults. Compared with the preintervention, VR induced the range of motion of knee flexion and extension significantly increased by 2.5% and 6%, respectively, and isokinetic peak torque and dynamic balance for muscle strength and dynamic balance increased by 33%–35% and 1.5%, respectively. In the three conditions, most outcomes between VR and NVR were comparable; however, the participants had a significantly higher knee joint reposition error after NVR than after VR, indicating that NVR would have a hampering knee joint proprioception effect. In particular, compared with static stretching, VR significantly increased the quadriceps muscle strength by 2-fold and dynamic balance by 1.8-fold. These findings suggest that athletic professionals may take VR into account for designing more efficient and effective preperformance routine to improve exercise performances. VR has high potential to translate into an on-field practical application. 相似文献
13.
Abstract In ice hockey, skating performance depends on the skill and physical conditioning of the players and on the characteristics of their equipment. CT Edge have recently designed a new skate blade that angles outward near the bottom of the blade. The objective of this study was to compare the frictional characteristics of three CT Edge blades (with blade angles of 4°, 6°, and 8°, respectively) with the frictional characteristics of a standard skate blade. The friction coefficients of the blades were determined by measuring the deceleration of an aluminium test sled equipped with three test blades. The measurements were conducted with an initial sled speed of 1.8 m · s?1 and with a load of 53 kg on each blade. The friction coefficient of the standard blades was 0.0071 (s=0.0005). For the CT Edge blades with blade angles of 4°, 6°, and 8°, friction coefficients were lower by about 13%, 21%, and 22%, respectively. Furthermore, the friction coefficients decreased with increasing load. The results of this study show that widely accepted paradigms such as “thinner blades cause less friction” need to be revisited. New blade designs might also be able to reduce friction in speed skating, figure skating, bobsledding, and luge. 相似文献
14.
摔跤滚桥技术分析及应用 总被引：5，自引：0，他引：5
分析了滚桥技术的动作结构，通过杠杆原理和稳定角原理对跪撑进行分析。对滚桥技术的训练主要是进行基本功、专项身体素质和约束练习的训练。同时也对滚桥技术的应用提出了建议。 相似文献
15.
Matt R. Cross Farhan Tinwala Seth Lenetsky Pierre Samozino Matt Brughelli Jean-Benoit Morin 《Journal of sports sciences》2017,35(22):2198-2203
Understanding the impact of friction in sled sprinting allows the quantification of kinetic outputs and the effective loading experienced by the athlete. This study assessed changes in the coefficient of friction (µk) of a sled sprint-training device with changing mass and speed to provide a means of quantifying effective loading for athletes. A common sled equipped with a load cell was towed across an athletics track using a motorised winch under variable sled mass (33.1–99.6 kg) with constant speeds (0.1 and 0.3 m · s?1), and with constant sled mass (55.6 kg) and varying speeds (0.1–6.0 m · s?1). Mean force data were analysed, with five trials performed for each condition to assess the reliability of measures. Variables were determined as reliable (ICC > 0.99, CV < 4.3%), with normal-force/friction-force and speed/coefficient of friction relationships well fitted with linear (R2 = 0.994–0.995) and quadratic regressions (R2 = 0.999), respectively (P < 0.001). The linearity of composite friction values determined at two speeds, and the range in values from the quadratic fit (µk = 0.35–0.47) suggested µk and effective loading were dependent on instantaneous speed on athletics track surfaces. This research provides a proof-of-concept for the assessment of friction characteristics during sled towing, with a practical example of its application in determining effective loading and sled-sprinting kinetics. The results clarify effects of friction during sled sprinting and improve the accuracy of loading applications in practice and transparency of reporting in research. 相似文献
16.
William M. Bertucci Simon Rogier Raoul F. Reiser II 《Journal of sports sciences》2013,31(14):1606-1613
Abstract Aerodynamic and rolling resistances are the two major resistances that affect road cyclists on level ground. Because of reduced speeds and markedly different tyre-ground interactions, rolling resistance could be more influential in mountain biking than road cycling. The aims of this study were to quantify 1) aerodynamic resistance of mountain-bike cyclists in the seated position and 2) rolling resistances of two types of mountain-bike tyre (smooth and knobby) in three field surfaces (road, sand and grass) with two pressure inflations (200 and 400 kPa). Mountain-bike cyclists have an effective frontal area (product of projected frontal area and drag coefficient) of 0.357 ± 0.023 m2, with the mean aerodynamic resistance representing 8–35% of the total resistance to cyclists' motion depending on the magnitude of the rolling resistance. The smooth tyre had 21 ± 15% less rolling resistance than the knobby tyre. Field surface and inflation pressure also affected rolling resistance. These results indicate that aerodynamic resistance influences mountain-biking performance, even with lower speeds than road cycling. Rolling resistance is increased in mountain biking by factors such as tyre type, surface condition and inflation pressure that may also alter performance. 相似文献
17.
高校轮滑体育教学课中运用多媒体技术探究 总被引：1，自引：0，他引：1
张耀光 《哈尔滨体育学院学报》2005,23(4)
轮滑运动是一项集健身、娱乐和观赏性于一体的体育项目。它有益于大学生身心健康,故深受学生的喜爱。目前已有不少高校开设轮滑教学课。通过对我校轮滑技术教学的实验研究发现:多媒体技术在轮滑教学上的运用,对丰富授课内容、增加教学手段、提高学生兴趣、培养学生自学能力有着积极的促进作用。 相似文献
18.
Paul William Macdermid Philip W. Fink Stephen R. Stannard 《Journal of sports sciences》2015,33(3):277-285
This investigation sets out to assess the effect of five different models of mountain bike tyre on rolling performance over hard-pack mud. Independent characteristics included total weight, volume, tread surface area and tread depth. One male cyclist performed multiple (30) trials of a deceleration field test to assess reliability. Further tests performed on a separate occasion included multiple (15) trials of the deceleration test and six fixed power output hill climb tests for each tyre. The deceleration test proved to be reliable as a means of assessing rolling performance via differences in initial and final speed (coefficient of variation (CV) = 4.52%). Overall differences between tyre performance for both deceleration test (P = 0.014) and hill climb (P = 0.032) were found, enabling significant (P < 0.0001 and P = 0.049) models to be generated, allowing tyre performance prediction based on tyre characteristics. The ideal tyre for rolling and climbing performance on hard-pack surfaces would be to decrease tyre weight by way of reductions in tread surface area and tread depth while keeping volume high. 相似文献
19.
Tokio Takagi Toshiharu Yokozawa Yuki Inaba Yuji Matsuda Hitoshi Shiraki 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(3):387-398
Since clubface orientation at impact affects ball direction and ball spin, the ability to control clubface orientation is one of the most important skills for golfers. This study presents a new method to describe clubface orientation as a function of the clubshaft motions (i.e., swing plane orientation, clubshaft angle in the swing plane, and clubshaft rolling angle) during a golf swing and investigates the relationships between the clubshaft motions and clubface orientation at impact. The club motion data of driver shots were collected from eight skilled golfers using a three-dimensional motion capture system. The degrees of influence of the clubshaft motions on the clubface orientation were investigated using sensitivity analysis. The sensitivity analysis revealed that the swing plane horizontal angle affected the clubface horizontal angle to an extent of 100%, that the clubshaft angle in the swing plane affected both the clubface vertical and horizontal angles to extents of 74 and 68%, respectively, and that the clubshaft rolling angle affected both the clubface vertical and horizontal angles to extents of -67 and 75%, respectively. Since the method presented here relates clubface orientation to clubshaft motions, it is useful for understanding the clubface control of a golfer. 相似文献
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