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体育运动中抛物体问题研究的基本方法 总被引:1,自引:0,他引:1
马明 《武汉体育学院学报》2008,42(7):64
基于抛物体运动规律对两类典型的抛物体运动(投掷项目、篮球投篮)进行了分析。在投掷项目中,投掷器械的飞行远度作为目标函数,在Excel中计算了不同的出手速度(V0)、出手角度(θ)及出手高度(H)对器械飞行远度的影响;在篮球运动中,以投篮的最小速度角和最小进篮误差作为目标函数,计算了不同的投篮距离、出手高度的情况下,投篮的最佳出手角度,寻找出篮球投篮最佳出手角的变化规律以便于运动员在实践中掌握和运用,提高投篮的命中率。 相似文献
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考虑空气阻力时标枪最佳出手角度研究 总被引:1,自引:0,他引:1
对考虑空气阻力时标枪的最佳出手角进行计算机仿真研究。通过刚体理论,推导了考虑空气阻力时标枪的动力学方程组,并在不同出手参数组合的情况下对标枪的出手角进行计算和分析。采用文献中的有关标枪的几何和物理参数,使用Mathematica数学软件进行方程的推导和数值计算。通过计算,得到标枪的初始攻角和俯仰角速度对出手角度选择的影响较显著。若无初始俯仰角速度时,最好的出手角度范围为37°~43°,其中42°最佳;最好的出手范围为39°~44°,其中43°最佳;攻角的适宜值为-9°~0°,初始俯仰角速度的适宜值为-12°/s~-6°/s。 相似文献
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标枪是投掷项目中最轻的器械,投出的远度是由器械出手的初速度、出手的角度和空气阻力三个因素决定的。就枝术原理而言,器械出手的初速度是决定运动成绩的主要因素。而器械出手的初速度又取决于投、搓力量的大小和整体动作速度。在诸多因素中,速度力量起主导作用,具备了力量素质 相似文献
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对推铅球最佳出手角度的重新认识 总被引:5,自引:0,他引:5
从数学角度对铅球出手前的运动过程进行生物力学分析,并对一般抛射运动规律进行数学逻辑分析。结果表明铅球出手速度与出手角度间存在一定的函数变化关系;该关系是影响和制约铅球抛射运动的约束条件。这一结果提示出手角度与出手速度间的合理配置是铅球获得最大远度的最佳出手角度。 相似文献
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对铅球投掷距离计算公式的探讨 总被引:1,自引:1,他引:0
在考虑空气阻力的情况下,目前采用的铅球投掷距离的计算公式是:式中m是铅球的质量,v_0是出手速度,α是出手角,h是出手高度,g是重力加速度,C是阻力系数,k是空气密度的1/2,s是铅球的最大截面积,L_0是出手 相似文献
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<正>推铅球运动属于动作持续时间短、技术性强、以绝对力量为基础、以速度为核心、爆发力要求较高的运动项目。由于完成推球动作的时间不超过1秒,最后用力到结束不超过0.5秒,只有较好的技术作为保障,才能在如此短暂的时间内取得好成绩。出手速度、出手角度和出手高度是影响推铅球成绩的三大因素,针对出手角度和出手高度的训练则是技术难点。 相似文献
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在投掷运动中,器械出手后的运动是斜抛运动。如果不考虑空气阻力、地斜角的影响,根据斜抛物体运动的规律,其最大远度(投掷距离)为; S=2V~2sin2θ/g 式子中的V为投掷初速度,θ为投掷角,g为重力加速度常数。从上式中,我们可以看出,最大远度S与投掷初速度的平方成正比,与投掷角也有关系。要想获得较大的远度,除了掌握适宜的投掷角,主要是增大投掷初速度。影响出手初速度的因素很多。这里只讨论器械从静止到出手运动的工作距离与器械出手初速度的关系。在器械没有离开人手的整个运动过程中,它始终受着人体和重力的作用。在此二力的合力作用下的运动,可以看成是沿 相似文献
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读了《运动生物力学》、《田径》等书后,书中关于推铅球出手角度的叙述,笔者感到不尽完善、不够明确,值得商榷。本文着重讨论滑步推球与原地推球的差异。一、原地推铅球 1.最佳状态的描述铅球出手后的运动是斜抛运动,运动轨迹是一条抛物线。设抛出点高度为h、抛出角(出手角)为α、抛出初速度(出手速度)为V_0、飞行时间为t、投掷远度为s,在不计空气阻力作用时,由质点运动学方程可得到 相似文献
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This study examined the effect of carbohydrate ingestion on metabolic and performance-related responses during and after a simulated 1h cycling time trial. Eight trained male cyclists (VO 2 peak = 66.5ml kg -1 min -1 ) rode their own bicycles mounted on a windload simulator to imitate real riding conditions. At a self-selected maximal pace, the cyclists performed two 1h rides (separated by 7 days) and were fed either an 8% carbohydrate or placebo solution. The beverages were administered 25 min before (4.5ml kg -1 ) and at the end (4.5ml kg -1 ) of the ride. With carbohydrate feeding, plasma glucose tended (P = 0.21) to rise before the time trial. Compared with rest, the plasma glucose concentration decreased significantly (P < 0.05) at the end of both rides, with no statistically significant difference being observed between treatments. Thereafter, plasma glucose increased significantly (P < 0.05) at 15 and 30 min into recovery, and was significantly higher at 30 min during the carbohydrate trial compared with the placebo trial. No significant changes in plasma free fatty acids were observed during the ride. However, a significant increase (P < 0.05) in free fatty acids was found at 15 and 30 min into recovery, with no difference between trials. Mean power output was significantly (P < 0.05) greater during the carbohydrate compared with the placebo trial (mean - S.E.: 277-3 and 269-3W, respectively). The greater distance covered in the carbohydrate compared with the placebo trial (41.5-1.06 and 41.0–1.06km, respectively; P < 0.05) was equivalent to a 44s improvement. We conclude that pre-exercise carbohydrate ingestion significantly increases endurance performance in trained cyclists during a 1h simulated time trial. Although the mechanism for this enhancement in performance with carbohydrate ingestion cannot be surmised from the present results, it could be related to a higher rate of carbohydrate oxidation, or to favourable effects of carbohydrate ingestion on the central component of fatigue. 相似文献
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Roy J. Shephard 《Journal of sports sciences》2013,31(7):603-620
The biology and medicine of rowing are briefly reviewed. Effort in a 2000 -m race is about 70% aerobic. Because the boat (and in some instances a cox) must be propelled, successful competitors are very tall, with a large lean mass and aerobic power. Large hearts may lead to erroneous diagnoses of a cardiomyopathy. Large respiratory minute volumes must be developed by chest muscles that are also involved in rowing. The vital capacity is typically large, and breathing becomes entrained. Expiration cannot be slowed relative to inspiration (as normally occurs at high rates of ventilation) and the limiting flow velocity may be reached, with the potential for airway collapse. Performance is strongly related to the power output at the ‘anaerobic threshold’, and lactate measures provide a guide to an appropriate intensity of endurance training. Peak blood lactate levels are higher in males (commonly 11–19 mmol·l -1 and occasionally as high as 25 mmol·l -1) than in females (9–11 mmol·l -1), probably because males have a greater muscle mass in relation to blood volume. The skeletal muscles are predominantly slow twitch in type, developing an unusual force and power at low contraction velocities. Many rowers have a suboptimal diet, eating excessive amounts of fat. Lightweight rowers also have problems of weight cycling. Aerobic power and muscle endurance often change by 10% over the season, but such fluctuations can be largely avoided by a well-designed winter training programme. Injuries include back and knee problems, tenosynovitis of the wrist and, since the introduction of large blades, fractures of the costae. 相似文献
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重新认识体育的社会关联 总被引:3,自引:1,他引:2
体育与政治之间存在一个悖论,体育的发展与经济实力之间没有直线相关,体育与教育部分重叠,体育与宗教最为近缘,体育可借用科学手段,体育的艺术禀性日益明显,体育与养生反映着两种人生观。 相似文献
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本文在专家访谈、问卷调查、数理统计和文献资料分析的基础上,探析了上海社区体育竞赛参与者的特点、参与者对社区体育赛事运作管理的看法等问题。在此基础上从引进社区体育赛事的志愿者、整合社区体育赛事的各种资源、开发社区体育竞赛的无形资产、组建非营利性的专业团队、规范社区体育赛事的服务管理等方面提出了进一步满足上海社区居民日益增长的体育竞赛参赛需求的对策与措施。 相似文献
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对全面把握游泳训练环节的探讨 总被引:4,自引:0,他引:4
从系统观点出发,结合训练实践,对全面把握游泳训练环节进行探讨。认为应强化非智力因素在运动员多年训练中的作用,在育材全过程中不断选材,从整体上把握动态训练的全过程,把培养高水平运动员的整个过程置于一个严格的科学控制之下。 相似文献
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影响和限制耐力性运动项目的成绩的生理因素是复杂的和多方面的,取决于训练的强度和运动成绩.大强度持续性运动可导致呼吸肌疲劳.运动性呼吸疲劳可能在决定运动耐量方面起到关键的作用:一方面通过直接影响运动肌力量的生成(外周疲劳),另一方面,通过肢体用力自感不安反馈引起工作肌运动单位输出功率下降(中枢疲劳).对呼吸肌进行训练,可能有助于提高耐力性项目的运动成绩. 相似文献
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青少年业余足球运动员运动倾向性5因素结构模型初探 总被引:3,自引:0,他引:3
根据Scanlan等人最新提出的运动倾向性理论模型,结合我国实际情况建立了青少年足球运动员运动倾向性5因素结构模型。运动倾向性被定义为:渴望和决心继续参加足球运动的心理状态。所建立的5因素结构模型认为,运动倾向性是由运动乐趣、参与选择、个人投入、社会约束及参与机会5个因素决定。经确定5个决定因素和运动倾向性的操作定义,编制了相应调查问卷,通过对北京市252名青少年足球运动员实测结果,建立运动倾向性及其影响因素的协方差结构模型,用Lisre 18分析的结果表明:该运动倾向性模型比较符合北京青少年足球运动员。其中运动乐趣、个人投入、参与机会和参与选择4因素对运动倾向性有影响;社会约束对运动倾向性影响不大。 相似文献
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The aim of this study was to assess the sensitivity of the lactate minimum speed test to changes in endurance fitness resulting from a 6 week training intervention. Sixteen participants (mean +/- s :age 23 +/- 4 years;body mass 69.7 +/- 9.1 kg) completed 6 weeks of endurance training. Another eight participants (age 23 +/- 4 years; body mass 72.7 +/-12.5 kg) acted as non-training controls. Before and after the training intervention, all participants completed: (1) a standard multi-stage treadmill test for the assessment of VO 2max , running speed at the lactate threshold and running speed at a reference blood lactate concentration of 3 mmol.l -1 ; and (2) the lactate minimum speed test, which involved two supramaximal exercise bouts and an 8 min walking recovery period to increase blood lactate concentration before the completion of an incremental treadmill test. Additionally, a subgroup of eight participants from the training intervention completed a series of constant-speed runs for determination of running speed at the maximal lactate steady state. The test protocols were identical before and after the 6 week intervention. The control group showed no significant changes in VO 2max , running speed at the lactate threshold, running speed at a blood lactate concentration of 3 mmol.l -1 or the lactate minimum speed.In the training group, there was a significant increase in VO 2max (from 47.9 +/- 8.4 to 52.2 +/- 2.7 ml.kg -1 .min -1 ), running speed at the maximal lactate steady state (from 13.3 +/- 1.7 to 13.9 +/- 1.6 km.h -1 ), running speed at the lactate threshold (from 11.2 +/- 1.8 to 11.9 +/- 1.8 km.h -1 ) and running speed at a blood lactate concentration of 3 mmol.l -1 (from 12.5 +/- 2.2 to 13.2 +/- 2.1 km.h -1 ) (all P ? 0.05). Despite these clear improvements in aerobic fitness, there was no significant difference in lactate minimum speed after the training intervention (from 11.0 +/- 0.7 to 10.9 +/- 1.7 km.h -1 ). The results demonstrate that the lactate minimum speed,when assessed using the same exercise protocol before and after 6 weeks of aerobic exercise training, is not sensitive to changes in endurance capacity. 相似文献