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李克 《沈阳体育学院学报》2012,31(2):109-111
为了指明羽毛球和网球高压球技术动作的差异性,为羽毛球和网球教学和训练提供定量的科学依据,使用三维立体摄影解析法获取羽毛球和网球高压球技术动作的运动学参数,并对数据进行统计学处理。研究结果表明:在蹬地击球过程中,大腿、小腿和足的运动顺序为大关节带动小关节;在整个击打过程中,肩、肘、腕三关节移动速度基本保持同步,肩关节角速度峰值最先出现,肘关节和腕关节角速度峰值出现时间基本同步;网球采用"棍打"的击球用力方式为主击球,羽毛球采用"鞭打"的击球用力方式为主击球。 相似文献
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运用文献资料法、专家访谈法、测量法、数理统计法测量健将、一级和二级运动员头顶封网技术运动学指标并分析原因,为羽毛球男子双打前场技术提供理论依据以及训练和比赛指导。结果表明,迎球挥拍阶段健将一级二级运动员右肘的角度、角速度和加速度差异非常显著;健将一级二级运动员在球拍触球阶段右腕的角度、角速度、加速度差异著性。结论认为：健将运动员各关节活动在力的传导作用下动作舒展性、动作衔接的紧密性、动作技能熟练程度优于一级和二级运动员;从迎球挥拍到随势挥拍结束的整个击球过程中,腕关节的控制对击球起关键作用。 相似文献
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搞清楚网球的各种关系,对打好网球,更好地享受网球的乐趣,是十分必要的。1技术、体能和心理的关系。网球技术主要是发球技术和正反手击球技术。练好发球技术,打高压球基本能解决。不同的是,发球是主动击球,击打高压球是被动击球。练好正反手击球技术,击打正反手各种类型的球同样能解决。 相似文献
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目的:探索不同落点(T内角、Body追身和Wide外角)网球侧上旋发球技术动作的运动学规律。方法:采用2台三维高速摄像机拍摄10名网球运动员侧上旋发球技术动作,使用北京体育大学视讯解析系统采集运动学参数,对原始数据进行平滑和归一化处理等(Fc=10)。结果:1)抛球引拍阶段:抛球时左肩水平投影角呈显著性差异,左肩、右肩和左膝关节角速度变量呈显著性相关(R=0.82),站位方式无显著性差异;2)"挠背"阶段:不同落点发球时发力顺序协调一致,由下至上逐步将力量传递至击球点;3)挥拍击球阶段:击球时刻不同落点间分速度和击球角度差异性显著,外角侧旋>追身侧旋>内角侧旋,内角上旋>追身上旋>外角上旋,外角Angle>追身Angle>内角Angle。击球点高度与身高的倍数为外角(1.32)、追身(1.25)和内角(1.21),击球点由内至外逐渐向右偏移;4)随挥阶段:击球后重心位移和速度分量未出现显著性差异,膝关节角度变化均值39.7±1.8°。结论:我国高校网球二级运动员亟需储备发球隐蔽性、击球点空间位置、挥拍轨迹和击球速度分量等方面的意识体系。应当继续以运动生物力学为手段加强网球各类型发球技术动作、各环节运动特征和发球所致损伤因素等进行系统化和精细化研究。 相似文献
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为了规范和提高我国广大网球教练员的执教水平,根据中国网球协会和国际网联的合作计划,定于 ２０００年 １１月 ２２日～１１月 ３０日在广州天河网球学校举办国际网联一级教练员培训班。 培训使用国际网联教练员手册,中国网球协会将选调名师教授包括教练员的作用、初学者的心理训练、战略和战术、球的控制、握拍分析、基本击球法、球的旋转、训练课的组织、教学过程——怎样向初学者接受网球、练习方法和教学方式、判断和纠正动作、短式网球教学等内容。 具有一定网球技术的人员（指正手击球、反手击球、正手截击、反手截击、高压、发球… 相似文献
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目的:研究踺子转体180°前手翻接直体前空翻类跳马动作,揭示这类跳马的运动学规律和技术特点.方法:对程菲和洪淑贞完成的"踺子转体180°前手翻接直体前空翻转体180"(简称"R180"),以及程菲完成的"踺子转体180°前手翻接直体前空翻转体540°"("程菲跳")进行三维运动学分析,对三组跳马动作身体重心的水平速度和垂直速度、主要关节的位移、关节角度、身体翻转角速度等运动学参数进行对比分析.结果:三组动作踏板时重心水平速度基本相同,踏板及推手阶段关键位置的关节角度相近,但"程菲跳"推离马重心垂直速度和第二腾空时间明显高于"R180",第二腾空转体角速度略大于"R180"的3倍,而翻腾角速度略小.结论:踺子转体180°前手翻接直体前空翻类跳马动作触马前的技术动作基本相同,难度较高的技术动作需要更高的推离马垂直速度和更快的第二腾空转体角速度. 相似文献
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本文采用平面定点定机摄像法对4名国际级乒乓球运动员的正手近远台攻球技术进行录像拍摄,采用美国APAS录像分析系统进行录像解析,获取近远台攻球技术动作各个阶段的定量运动学数据。结果表明:受试者远台击球时刻肘关节角度明显大于近台击球时肘关节角度;肘关节角速度的变化遵循慢——快——慢的节奏;在挥拍击球阶段远台攻球时肩关节角度明显大于近台;正手攻球过程中重心位移变化近台大于远台但重心移动速度远台大于近台。 相似文献
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本文通过运用文献资料法、逻辑分析法等对网球初学者在进行正手击球时出现的问题进行研究,着重对网球初学者学习正手击球时易犯错误动作进行分析。正手击球是网球初学者学习网球的最基本的,也是最重要的技术动作。为了让初学者便于掌握正手击球动作,在教学和训练中,要抓住技术关键,有针对性地训练,分析出现错误动作的原因,以便及时纠正,以求达到最佳的学习效果,尽快掌握网球基本技术动作。 相似文献
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高校体育合作学习理念探索 总被引：4，自引：0，他引：4
理念是个体认知、经验、行为在头脑中系统反映。“体育合作学习”是指学生以小组练习为基本形式，在小组中为了体育的学习任务共同努力，在明确责任的前提下，互相鼓励、相互指导、相互帮助的互动性学习方式。其强调的是个体责任；发挥的是集体智慧；倡导的是主动学习；学习在教师的参与下进行。要求由个人竞争转变为小组竞争，形成“组内同学合作，组间同学竞争”的新格局，达到共同学习，共同提高的目标。 相似文献
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AbstractThis study attempted to validate an anthropometric equation for predicting age at peak height velocity (PHV) in 198 Polish girls followed longitudinally from 8 to 18 years. Maturity offset (years before or after PHV) was predicted from chronological age, mass, stature, sitting height and estimated leg length at each observation; predicted age at PHV was the difference between age and maturity offset. Actual age at PHV for each girl was derived with Preece–Baines Model 1. Predicted ages at PHV increased from 8 to16 years and varied relative to time before and after actual age at PHV. Predicted and actual ages at PHV did not differ at 9 years, but predicted overestimated actual age at PHV from 10 to 16 years. Girls of contrasting maturity status differed in predicted age at PHV from 8 to 14 years. In conclusion, predicted age at PHV is dependent upon age at prediction and individual differences in actual age at PHV, which limits its utility as an indicator of maturity timing in general and in sport talent programmes. It may have limited applicability as a categorical variable (pre-, post-PHV) among average maturing girls during the interval of the growth spurt, ~11.0–13.0 years. 相似文献
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Nicola Bullock David T. Martin Angus Ross Doug Rosemond Terry Holland Frank E. Marino 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):351-360
This study characterizes key elements of the start in elite female World Cup skeleton athletes. The top 20 female competitors in three World Cup races were videotaped within a calibrated space to allow the following components of the start to be quantified: (1) acceleration (velocity at 15-m mark, time to 15-m mark), (2) capacity (time to load, total number of steps to load), and (3) load (velocity at 45-m mark). A correlation analysis was used to establish the relationship between the variables of interest and overall start time (15- to 65-m mark). Velocity at the 15-m mark accounted for 86% of the variance in overall start time at St. Moritz and 85% at Sigulda. A stepwise regression analysis revealed that approximately 89% of the variation in start time could be explained by velocity at the 15-m mark, time to load, and velocity at the 45-m mark. Of the variables analysed in this study, rapid acceleration to attain a high velocity at the 15-m mark was the most important component of a fast overall start time. The importance of the time to load and velocity at the 45-m mark vary according to the different track characteristics. 相似文献
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《European Journal of Sport Science》2013,13(4):153-158
Abstract The purpose of this study was to investigate the influence of a warm environment on thermoregulation and energy expenditure during sub-maximal prolonged exercise in humans. Six healthy male subjects cycled for 120?min at an intensity of 60% maximal oxygen uptake (Vo2max) at three environmental temperatures (10°C, CT; 20°C, MT; and 30°C, WT). Although oxygen uptake at WT showed a significantly lower value compared to those at MT and CT, no significant differences of respiratory exchange ratio were observed among the three environmental trials. A remarkable decrease in total energy expenditure during the 120-min exercise at WT was observed in comparison with those at MT and CT (p<0.05). Changes in rectal temperature, mean skin temperature, and mean body temperature at WT were significantly higher than those at both MT and CT. Although increases in mean body temperature from rest every five minutes during exercise were not different among three environmental temperatures, mean energy expenditures every five minutes at WT were lower compared with those at MT and CT (p<0.05). These results suggest that the increase in energy expenditure for physical exertion is substantially reduced during prolonged sub-maximal exercise in a warm environment. This acute alteration in the energy metabolism may contribute to inhibition of excess heat production and enable prolonged exercise in a warm environment. 相似文献
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Abstract In this study, we examined the long-term reductions in maximal isometric force (MIF) caused by a protocol of repeated maximal isometric contractions at long muscle length. Furthermore, we wished to ascertain whether the reductions in MIF are dependent on muscle length — that is, are the reductions in MIF more pronounced when the muscle contracts at a short length. The MIF of the elbow flexors of seven young male volunteers was measured at five different elbow angles between 50° and 160°. On a separate day, the participants performed 50 maximal voluntary isometric muscle contractions with the elbow flexors at a lengthened positions that is, with the shoulder hyperextended at 45° and the elbow joint fixed at 140°. Following this exercise, the MIF at the five elbow angles, range of motion, muscle soreness and plasma creatine kinase activity were measured at 24 h intervals for 4 days. On day 1, the decline in MIF was higher at the more acute elbow angles of 50° (42±8%) and 70° (39±8%; both P<0.01) than at 90° (26±4%) and 140° (16±3%; both P<0.01). No significant reduction in MIF was evident at an elbow angle of 160°. Maximal isometric force at an elbow angle of 140° was fully restored on day 3, whereas at an angle of 50° it remained depressed for the 4 day observation period. Restoration of MIF was a function of the elbow angle, with force recovery being less at the smaller angles. The range of motion was decreased by 14±2° on day 1 (P<0.01) and did not return to baseline values by day 4. Muscle soreness ratings remained significantly elevated for the 4 day period. Serum creatine kinase peaked on day 1 (522±129 IU, P<0.01) and decreased thereafter. We conclude that the disproportionate decrease in MIF at the small elbow angles and the length-specific recovery in MIF after repeated maximal isometric contractions at long muscle length may be explained by the presence of overstretched sarcomeres that increased in series compliance of the muscle, therefore causing a rightward shift of the force-length relationship. 相似文献
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目的:观察世居高原自行车运动员在亚高原训练期间的机能变化.方法:以8名世居高原(海拔1910m)男子公路自行车运动员为研究对象,系统测试每名运动员在下亚高原前、亚高原(海拔1300m)训练第2天、第4天、第8天、第18天、第25天及第32天的红细胞(RBC)、红细胞压积(Hct)、血红蛋白(Hb)、血清睾酮(T)、皮质醇(C)、晨脉(HR)、脉搏血氧饱和度(SpO2)等血液生化指标及生理指标.结果:①世居高原运动员下到亚高原环境,大气氧分压增加了10mmHg,运动员Sp02上升了1％,晨脉下降了5次/分,均无统计学差异.②运动员RBC、Hct、Hb在亚高原训练的第2天开始下降,并在第4天降至最低,RBC下降明显(P＜0.01),较高原下降了9.25％,Hb稍有下降;一周后各血象指标逐渐回升,并在第25天时升至最高水平,Hb升高了4.33％,且差异显著(P＜0.05),RBC无变化.③运动员血清T在亚高原训练的前3周与高原相比无差异,3周后升高,并在第25天显著升高(P＜0.05),较高原升高15.56％;C在第二天较高,随后下降,T/C比值变化甚微.结论:世居高原男子自行车运动员亚高原训练期间第1周身体机能状况较差,随后逐渐恢复,在3周后达到最好水平.提示世居高原男子自行车运动员到亚高原比赛时的最佳时间为下至亚高原3周后. 相似文献
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目的:基于决策树模型探讨幼儿体质的影响因素及其交互关系。方法:募集学龄前儿童4621名(36~83月龄)。参照《国民体质测定标准手册(幼儿部分)》进行体质测试与综合评级(合格、不合格);问卷调查幼儿出生信息、育儿方式、静坐与身体活动、膳食营养、睡眠、父母情况6个一级指标下分的59个二级指标变量信息;采用IBM SPSS modeler创建CHAID决策树模型。结果:幼儿体质的重要影响因素排序依次为周末身体活动(PA)、周末静坐行为(SB)、性别、周末中-大强度身体活动(MVPA)、上学日PA、钙、上学日SB。决策树模型显示,根节点变量周末PA“>3 h/天”(95.35%)的幼儿体质合格率与“1~3 h/天”(91.43%)、“≤0.5 h/天”(85.43%)相比具有非常显著性差异(P=0.000)。周末PA“>3 h/天”的第2、3层叶节点变量分别为周末SB、上学日PA,“1~3 h/天”“≤0.5 h/天”的第2层叶节点变量均为性别。其中,“1~3 h/天”的3~5层叶节点变量包括周末与上学日MVPA、上学日SB、钙等。结论:周末PA是影响幼儿体质的最关键因素。幼儿周末PA应超过3 h/天的国际推荐量标准,并在此基础上减少周末SB时间、增加上学日PA时间。身体活动与静坐行为、性别、钙摄入等对不同层次类型幼儿的体质促进具有决策意义。 相似文献
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Timothy J. Suchomel George K. Beckham Glenn A. Wright 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(1):87-95
This study examined the impact of load on lower body performance variables during the hang power clean. Fourteen men performed the hang power clean at loads of 30%, 45%, 65%, and 80% 1RM. Peak force, velocity, power, force at peak power, velocity at peak power, and rate of force development were compared at each load. The greatest peak force occurred at 80% 1RM. Peak force at 30% 1RM was statistically lower than peak force at 45% (p = 0.022), 65% (p = 0.010), and 80% 1RM (p = 0.018). Force at peak power at 65% and 80% 1RM was statistically greater than force at peak power at 30% (p < 0.01) and 45% 1RM (p < 0.01). The greatest rate of force development occurred at 30% 1RM, but was not statistically different from the rate of force development at 45%, 65%, and 80% 1RM. The rate of force development at 65% 1RM was statistically greater than the rate of force development at 80% 1RM (p = 0.035). No other statistical differences existed in any variable existed. Changes in load affected the peak force, force at peak power, and rate of force development, but not the peak velocity, power, or velocity at peak power. 相似文献
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In this study, we examined the long-term reductions in maximal isometric force (MIF) caused by a protocol of repeated maximal isometric contractions at long muscle length. Furthermore, we wished to ascertain whether the reductions in MIF are dependent on muscle length--that is, are the reductions in MIF more pronounced when the muscle contracts at a short length. The MIF of the elbow flexors of seven young male volunteers was measured at five different elbow angles between 50 degrees and 160 degrees. On a separate day, the participants performed 50 maximal voluntary isometric muscle contractions with the elbow flexors at a lengthened position; that is, with the shoulder hyperextended at 45 degrees and the elbow joint fixed at 140 degrees. Following this exercise, the MIF at the five elbow angles, range of motion, muscle soreness and plasma creatine kinase activity were measured at 24 h intervals for 4 days. On day 1, the decline in MIF was higher at the more acute elbow angles of 50 degrees (42 +/- 8%) and 70 degrees (39 +/- 8%; both P<0.01) than at 90 degrees (26 +/- 4%) and 140 degrees (16 +/- 3%; both P<0.01). No significant reduction in MIF was evident at an elbow angle of 160 degrees. Maximal isometric force at an elbow angle of 140 degrees was fully restored on day 3, whereas at an angle of 50 degrees it remained depressed for the 4 day observation period. Restoration of MIF was a function of the elbow angle, with force recovery being less at the smaller angles. The range of motion was decreased by 14 +/- 2 degrees on day 1 (P<0.01) and did not return to baseline values by day 4. Muscle soreness ratings remained significantly elevated for the 4 day period. Serum creatine kinase peaked on day 1 (522 +/- 129 IU, P<0.01) and decreased thereafter. We conclude that the disproportionate decrease in MIF at the small elbow angles and the length-specific recovery in MIF after repeated maximal isometric contractions at long muscle length may be explained by the presence of overstretched sarcomeres that increased in series compliance of the muscle, therefore causing a rightward shift of the force-length relationship. 相似文献
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长江三角洲地区35～45 岁年龄段非体育人口现状调查与分析 总被引：2，自引：0，他引：2
通过文献资料与问卷调查法,对长三角地区35～45岁非体育人口的现状、体育人口标准的三个条件因素对该年龄段的非体育人口的影响以及本年龄段非体育人口的体育态度趋向进行调查和描述性分析,结果表明:这一地区35～45岁年龄段的非体育人口比例仍高于全国2000年的比例水平;该年龄段非体育人口具有很大数量的“潜在体育人口,”在短时间之内增加该年龄段的体育人口数量是完全可行的。并对此提出相应建议。 相似文献