共查询到20条相似文献，搜索用时 171 毫秒
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《体育博览》1999,(1)
送球入袋是一项最基本的实用球技练习方法。研究如何将目标球送入球袋,并如何做好送球入袋的练习,是非常重要的课题。因为台球主要打法都是击打主球,使主球撞击目标球,将其送入球袋而得分和取胜。送球入袋的练习方法基本有:垂直袋口直线球、斜对袋口直线球、非直线球、弧线球、倒顶球、反弹球、金三角和借力球等。1.垂直袋口直线球垂直袋口直线球就是主球、目标球和袋口三者形成一条直线,两且与袋口半圆弧顶点的切线垂直垂直袋口直线球是最基本的送球入袋方法,这种送球方法练习好了,可以为其他角度送球打下良好的基础。在进行练习时,将主球、目标球垂直袋口摆成直线,反复进行将目标球送入球袋的练习。练习时目标球与袋口的距离要由近而远,主球与目标球之间的距离要由短而长。 相似文献
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不同气压、不同风速及对称性对排球飘球的影响 总被引：1，自引：0，他引：1
采用风洞实验通过对在不同风速、不同气压下以及是否对称的球的飘晃距离和飘晃特点进行研究。结果表明:1)同一气压下,随着风速的不断增大,飘球产生的飘晃距离呈现先增大而后减小再增大的现象;2)不同气压下,飘球产生最大飘晃距离的临界速度均为10 m/s~15m/s,晃距约为0.5~0.6 m;3)气压对排球的飘晃影响不大,但球的对称与否会对飘球的晃动产生影响。 相似文献
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现在许多学校搞特色学校,创建国家级示范性学校,特别是成立全国青少年体育俱乐部,对我们老师和学生要求比较高,相应技术水平也要提高。但是在的乒乓球课中许多同学在正手攻球的练习,连最基本的发球都不会,训练的强度和密度不够,经常来回捡球,浪费时间,手感没有了,也没有成功的喜悦。这样同学们会逐渐产生厌恶,对中学生的心理和身体都有影响。因此,本文探讨了在新课标下的乒乓球选项课中怎样提高中学生的正手攻球的连续性的问题。 相似文献
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对台球直线球教学中常见的错误动作进行了深刻地分析,并根据直线球的技术特点提出了纠正错误动作的方法和应注意的问题. 相似文献
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Wulf G McNevin NH Fuchs T Ritter F Toole T 《Research quarterly for exercise and sport》2000,71(3):229-239
Experiment 1 examined whether it is more advantageous to direct learners' attention to the external effects of their movements relative to other external cues. Two groups of participants hit tennis balls at a target, with one group focusing on the ball coming toward them (antecedent) and the other group focusing on the ball leaving the racket (effect). The effect group demonstrated more effective learning. Experiment 2 examined whether it is more beneficial if the movement effect is related to the movement technique, relative to other movement effects (e.g., outcome). Two groups of participants hit golf balls at a target. The attention of these groups was directed to the club or the ball trajectory, respectively. The club group showed more effective learning than the target group, suggesting that focusing on technique-related effects is more effective. 相似文献
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Worobets J Stefanyshyn D 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(2):239-248
The role of shaft stiffness on the golf swing is not well understood. Studies in which golfers hit balls with clubs of varying shaft flex have reported changes in ball distance. The results of mathematical models suggest that shaft stiffness affects only the orientation of the clubhead at impact, not the speed of the clubhead, but there are no experimental results validating these findings. The purpose of this study was therefore to experimentally examine the influence of shaft stiffness on clubhead kinematics at ball impact. Forty golfers hit 10 balls with each of five drivers varying in shaft stiffness from 'Ladies' to 'Extra-Stiff', in a double-blind study design. The motions of three reflective markers attached to the clubhead were captured with a high-speed motion analysis system. At ball impact, shaft stiffness had a statistically significant influence on clubhead speed for 27 subjects, on loft angle for 11 subjects, and on lie angle for all 40 subjects. No effect was observed on face angle, in to out path angle, or attack angle. These results show that shaft stiffness can affect ball launch conditions by altering clubhead speed and/or loft angle. 相似文献
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The effects of three different colour patterns on the surface of volleyballs (versus that of a plain white ball) on the behaviour of a reception player were examined by presenting sidespin volleyball serves. Expert (n = 10) and novice (n = 10) volleyball players intercepted volleyballs projected straight at them or at an initial angle of 9.5 degrees outwards but eventually curving towards the players' original position. In the latter trajectories, players generally took one or more steps laterally before returning to the landing position of the ball. These excursion patterns were significantly more pronounced with the white balls than the coloured balls. Differences between balls of different colour combinations were also observed. The first finding supports the thesis that next to a prospective type of control, such as on-line maintenance of a certain spatiotemporal relationship between the player and the ball, properties of the ball itself allow prediction of the future path of the ball. Differences between types of colour patterns are explained within the framework of the between-colours wavelength contrasts of each type of ball. 相似文献
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NORIYUKI TABUCHI TOMOYUKI MATSUO KEN HASHIZUME 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(1):17-30
The aims of this study were to examine whether batters hit stationary balls at the time of peak speed of the bat head and whether the impact occurs at the lowest point of the bat trajectory. Eight university baseball players hit three balls, each hung with a string; each ball was made of a different material and was different in weight. Bat movement was captured by four 240-Hz infrared cameras and analysed three-dimensionally. Time for peak speed of the bat head varied according to the conditions. When stationary balls of standard weight were used, the bat head was at maximum speed at impact with the ball; then, it decelerated drastically owing to the impact. In contrast, maximum speed was obtained after impact when lightweight stationary balls were used. The time–speed profile of the bat head before impact in the lightweight ball condition was identical with that in the standard weight ball condition. Regardless of conditions, the timing of the lowest point of the bat head was nearly identical for each batter and most participants hit the stationary balls at about the lowest point of the bat trajectory 相似文献
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Matthieu Lenoir Joost Vansteenkiste Jelle Vermeulen Dirk de Clercq 《Journal of sports sciences》2013,31(8):871-879
The effects of three different colour patterns on the surface of volleyballs (versus that of a plain white ball) on the behaviour of a reception player were examined by presenting sidespin volleyball serves. Expert (n = 10) and novice (n = 10) volleyball players intercepted volleyballs projected straight at them or at an initial angle of 9.5° outwards but eventually curving towards the players' original position. In the latter trajectories, players generally took one or more steps laterally before returning to the landing position of the ball. These excursion patterns were significantly more pronounced with the white balls than the coloured balls. Differences between balls of different colour combinations were also observed. The first finding supports the thesis that next to a prospective type of control, such as on-line maintenance of a certain spatiotemporal relationship between the player and the ball, properties of the ball itself allow prediction of the future path of the ball. Differences between types of colour patterns are explained within the framework of the between-colours wavelength contrasts of each type of ball. 相似文献
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Tabuchi N Matsuo T Hashizume K 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(1):17-30
The aims of this study were to examine whether batters hit stationary balls at the time of peak speed of the bat head and whether the impact occurs at the lowest point of the bat trajectory. Eight university baseball players hit three balls, each hung with a string; each ball was made of a different material and was different in weight. Bat movement was captured by four 240-Hz infrared cameras and analysed three-dimensionally. Time for peak speed of the bat head varied according to the conditions. When stationary balls of standard weight were used, the bat head was at maximum speed at impact with the ball; then, it decelerated drastically owing to the impact. In contrast, maximum speed was obtained after impact when lightweight stationary balls were used. The time-speed profile of the bat head before impact in the lightweight ball condition was identical with that in the standard weight ball condition. Regardless of conditions, the timing of the lowest point of the bat head was nearly identical for each batter and most participants hit the stationary balls at about the lowest point of the bat trajectory. 相似文献
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Caljouw SR Van der Kamp J Savelsbergh GJ 《Research quarterly for exercise and sport》2010,81(4):410-415
When hitting kicking, or throwing balls at targets, online control in the target area is impossible. We assumed this lack of late corrections in the target area would induce an effect of a single-winged Müller-Lyer illusion on ball placement. After extensive practice in hitting balls to different landing locations, participants (N = 9) had to hit a ball to a distant target specified by the vertex of a single-winged Müller-Lyer configuration. Impact velocity was not significantly "tricked" by the pictorial illusion, suggesting that, even when late corrections in the target area are absent, some motor behaviors are not susceptible to the influence of the visual environment surrounding the target. 相似文献
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Hiromu Katsumata Keita Himi Tenpei Ino Kyohei Ogawa Takehiro Matsumoto 《Journal of sports sciences》2017,35(24):2468-2480
Baseball batters must react to pitches delivered to different locations within the strike zone by modulating their movements. In tee-batting practice, such batters place a ball on a tee stand at a location, where they intend to hit the ball, assuming a particular pitch’s trajectory. In the present study, we analysed three-dimensional movements in tee-batting to identify characteristics of the batters’ intended impact locations across the strike zone, thereby investigating spatiotemporal features of movement modulation. More specifically, 10 experienced baseball batters performed tee-batting at their preferred impact locations at nine different heights and courses within the strike zone. The distribution of impact locations showed regularity, i.e., the location shifted forward for balls placed high and inside, while it shifted backward for balls placed low and outside. Furthermore, trunk and arm movements showed systematic modulation as the impact locations changed. The duration of bat movement was also location dependent, i.e., hitting the inside ball took more time than hitting the outside ball. Our results indicate that even though movements among body segments were properly coordinated to adjust the bat swing for different impact locations, fine timing adjustments were also required to hit the ball at those preferred impact locations and therefore properly react to differences in flight paths. 相似文献
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In this paper, we present results on the measurement and analysis of the sound that is produced by the sharp impact loading of a golf ball by a flat massive object (e.g. the face of a golf club). We discuss: (a) the motivation for such a study; (b) some necessary background information on how golf balls vibrate; (c) the techniques used to acquire and analyse the data; and (d) an analysis of the sound made by dropping balls on a smooth, massive concrete target surface. These results establish a simple method for rapid and non-destructive measurement of the effective high-frequency elastic shear moduli of balls and ball cores. 相似文献