排球运动员下肢起跳肌群等速测试的研究

用Biodex等速测力系统对排球运动员进行了下肢3关节肌的力量测试,获得了在两种不同速度下的等动测试数据,并把所得数据与运动学拍摄的结果相结合进行了分析研究.结果显示运动员的弹跳能力与下肢起跳肌群等速测试的结果较为一致;下肢髋关节和膝关节起跳肌群肌肉力量和肌肉耐力对起跳能力有较大影响;功疲劳度可以作为评价运动员肌肉耐力素质的有效指标.     

不同弹跳能力的3名运动员其原地纵跳的运动生物力学指标的比较

根据力学原理,本文建立了不同运动员间进行原地纵跳运动生物力学指标同步比较的方法。三名不同弹跳能力的运动员其原地纵跳进行了测力与录相同步分析。研究表明,能力强者在技术上表现出髋、膝、踝关节处极强的协调发力能力,而能力差者均出现滞后或超前的不协调性发力;不同能力的运动员在膝关节处发力较为接近,肩关节均是提前发力。但能力强者具有较强的肩关节发力能力,能力最差者则在肩、踝等关节处发力能力明显不足。     

评定运动员弹跳训练水平的几个公式

目前,国内外使用的测试运动员弹跳训练水平的方法,大都侧重于测试其弹跳能力的某个方面,因而其片面性较大,难以客观地反映运动员在实战中的运用能力。苏联拉脱维亚体育学院阿芙娜塞娃提出一套比较全面的方法,现介绍如下。评定弹跳训练水平的两个任务是:(1)研究评定运动员弹跳耐力的方法;(2)探讨评定运动员训练水平的综合标准。通常是用一组弹跳的平均高度(Hcp)     

对提高学生立定跳远成绩的探讨

<正>立定跳远是衡量下肢爆发力与弹跳能力的客观手段,是中小学生身体素质情况重要指标之一,所以在中小学体质测试、中考体育测试中,都把立定跳远作为考试项目。立定跳远不是田径的正式比赛项目。自从奥     

中国优秀女子沙滩排球运动员专项运动素质特征及其评价

目的:探讨中国优秀女子沙排运动员专项运动素质特征。方法:根据文献资料及专家问卷确定其专项运动素质特征指标后,对包括备战2008年奥运会的国家女子沙滩排球队队员在内的现役全部女子沙滩排球运动员进行测试。国外优秀女子沙排运动员资料来自国际排联。结果:(1)中国优秀女子沙滩排球运动员速度灵敏性、弹跳、挥臂能力、柔韧性均优于中国一般运动员。(2)对中国优秀女子沙滩排球运动员专项运动素质的评价包括评价指标及指标贡献率的确定、目标结构模型的建立。结论:(1)与中国一般女子沙滩排球运动员相比,中国优秀女子沙滩排球运动员的专项运动素质以动作速度快、爆发力大、柔韧性好、协调能力强和专项耐力好为特征。但与世界顶尖女子沙滩排球运动员相比,中国优秀女子沙排运动员的快速动作和爆发力相对较差。(2)速度灵敏性、弹跳能力、挥臂能力是中国优秀女子沙滩排球运动员的核心素质。(3)中国优秀女子沙滩排球运动员专项运动素质评价指标包括沙地X字移动、助跑摸高、掷实心球、坐位体前屈和沙地渐进式折回跑五项,且其贡献率依次降低。(4)建立中国优秀女子沙滩排球运动员专项运动素质评价的目标结构模型有助于中国国家女子沙滩排球队树立训练目标,使训练更有目的性和实效性。     

少年女排弹跳素质训练监控指标体系与评价标准的研究

以运动训练控制理论、体育测量理论为指导,依据少年女子的生理解剖特点,结合中学和业余体校的实际训练条件,借助多元统计数学方法和计算机技术手段,从影响弹跳素质的各种身体素质指标人手.限定性地展开对弹跳素质具有影响效力的诸指标的定量分析,并探讨其影响效应的强度序列,遴选与确定反映少年女排弹跳素质发展水平的监控指标体系,并构建出弹跳素质训练发展的数字目标模式和评价标准体系,为科学控制少年女排弹跳训练过程提供了数字化的参考依据.     

CUBA男子篮球运动员身体素质测试结果分析

运用问卷调查、定量测试等方法，对8支CUBA男子篮球运动员各项身体素质指标进行了测试。发现后卫、前锋、中锋不同位置队员在速度、柔韧和下肢力量的差异不具有显著性意义；仰卧起坐、弹跳和速度耐力三项中，三种位置队员间的差异都具有非常显著性意义；灵敏素质、一般耐力素质方面，各位置队员问的差异都具有显著性意义。     

短跑跨栏摆动训练的运动传感器监测和能力评价研究

田径短跨运动是许多竞技运动的基础,是典型的周期性运动.运动员肢体的高速摆动能力是一个重要的专项能力.训练现场的实时定量化的测试评价和监控,对当前高水平运动训练有迫切需求.运动传感器检测技术的发展为运动训练的测试分析提供了有效的工具.本研究探讨了力学传感器对短跨运动员摆动训练的定量检测方法,建立了训练过程的专项能力与力学参数之间的联系,实现了运动能力的定量评价和训练效果的实时反馈,初步创建了“信号回馈”式辅助训练的方法.     

女子排球运动员身高与弹跳能力的比较研究

通过对1972-2004年世界优秀女子排球运动员的身高及弹跳能力数据的统计，分析其身高与弹跳能力的关系。结果证明：30a间身高增加10．02cm，从1997-2004年的8a时间弹跳提高0．75cm，不同位置身高与弹跳力增加的幅度不同。弹跳能力与身高相比，对比赛的胜负影响更大。     

关于青少年游泳运动员选材综合评价标准的研究

国内外对青少年运动员科学选材的研究工作非常重视,新指标的开发与多指标的综合评价尤为令人关注本文从游泳项目入手,确定了74项测试指标(包括形态、机能、素质、心理、发育等),对四川省500余名青少年游泳运动员进行了连续三年的跟踪测试(1988—1990年).应用相关分析与逐步回归分析的方法,计算出影响青少年游泳运动员竞技能力的各测试指标的权重,建立了各测试指标与游泳竞技能力之间关系的数学表达式,并以此为根据建立起青少年游泳运动员选材综合评价的标准。     

Which drop jump technique is most effective at enhancing countermovement jump ability, “countermovement” drop jump or “bounce” drop jump?

Abstract

The drop jump is a popular form of plyometric exercise often undertaken to enhance countermovement jump ability (jump height). Despite its popularity the effects of drop jump training on countermovement jump height are often inconsistent. Such inconsistencies may be as a result of differences in the drop jump technique being employed. Two recognised forms of drop jump are the “countermovement” drop jump and the “bounce” drop jump and the current study examined the effects of eight weeks of training with these drop jump techniques on countermovement jump height. Methods: A kinetic and kinematic analysis of each participant's countermovement jump, bounce- and countermovement drop jumps was undertaken prior to training. Participants were then randomly assigned to a bounce drop jump training group (n = 34), a countermovement drop jump training group (n = 35) or a control group (n = 34). Changes in jump height were examined following training. Results: The countermovement drop jump training group increased their countermovement jump height by 2.9 cm (6%), which was a significant change (P < 0.05) in comparison to that experienced by the bounce drop jump (-0.2 cm, -0.4%) and the control group (-0.1 cm, 0.2%). Conclusion: The countermovement drop jump may be more effective than the bounce drop jump at enhancing countermovement jump height.     

排球运动员的弹跳力训练

提高排球运动员的弹跳力,对于提高排球运动员的各种扣球、拦网、跳发球技术,丰富排球运动的各种战术形式及其变化,都起着至关重要的决定性作用。文章就弹跳力方面进行了理论分析并提出了训练建议。     

青少年男子排球运动员弹跳力素质研究

弹跳力是青少年男子排球运动员应重点发展的身体素质。在弹跳力训练中应充分考虑到青少年排球运动员身体生长发育的特点、弹跳力素质训练的规律以及排球运动的专项特点。通过文献分析对排球弹跳力的定义、青少年运动员生理特点以及发展弹跳力训练的方法手段和应注意的问题进行了系统的研究。     

Predicting the playing character of cricket pitches

A cricket pitch is a prepared strip of compacted soil and closely mown turf onto which the bowler projects the ball. The surface is of fundamental importance to the game and groundstaff seek to ensure that the ball rebound is of sufficient pace, bounce and consistency to promote skill in both the batsman and bowler. The scientific understanding of the factors that influence the playing quality of a pitch is incomplete and groundstaff often rely on experience and ‘rules of thumb’. A major programme of research was undertaken to determine the effectiveness of a range of pitch measurement apparatus that are perceived to provide indications of playing character. Over three seasons, 18 fieldwork visits were completed at 11 different first-class county grounds. Pitches were tested at the end of each match and direct assessments of pace, bounce and consistency were achieved by employing an artificial bowler and high speed video arrangement. Measurements of surface friction, hardness and restitution were also recorded. It was found that no single pitch measurement was able to provide a reliable indication of pace or bounce, but, when the measurements were combined in a simple Newtonian model, good predictions of pace were achieved. The study revealed a simple method by which groundstaff can predict pace during crucial stages in pitch preparation. However, the study also showed that bounce is affected by levels of pitch deformation and that development of impact models and bespoke measurement tools is needed to reliably predict variation in bounce.     

Finite element modelling and experimental study of oblique soccer ball bounce

In this study, we develop a finite element model to examine the oblique soccer ball bounce. A careful simulation of the interaction between the ball membrane and air pressure in the ball makes the model more realistic than analytical models, and helps us to conduct an accurate study on the effect of different parameters on a bouncing ball. This finite element model includes a surface-based fluid cavity to model the mechanical response between the ball carcass and the internal air of the ball. An experimental set-up was devised to study the bounce of the ball in game-relevant impact conditions. Ball speed, angle, and spin were measured before and after the bounce, as well as ball deformation and the forces during the impact. The finite element model has been validated with three different sets of data, and the results demonstrate that the finite element model reported here is a valuable tool for the study of ball bounce. After validation of the model, the effect of the friction coefficient on soccer ball bounce was studied numerically. Simulation results show that increasing the friction coefficient may result in reversal of the horizontal impact force.     

青年男排运动员身体素质与比赛成绩的相关分析

运用文献资料法、测量法和数理统计法,通过参加全国青年男排球联赛运动员的身体素质和运动成绩间的相关关系进行统计学分析,从而寻找我国青年男子排球运动训练的基本规律和关键因素。研究表明:在训练过程中应以身体素质提高为重点,应加强弹跳力、灵敏性和快速移动能力的训练,为青年男子排球科学训练提供科学依据。     

篮球运动员弹跳力的生物力学分析

以黑龙江省青年男篮、哈尔滨体育学院男篮为研究对象,采用CybexNorm多关节等速测力仪和运动录像相结合的方法,对运动员的原地纵跳、上步纵跳及下肢等速肌力特征进行了分析。研究发现,专业队和非专业队篮球运动员膝关节伸肌的退让收缩能力、下肢弱侧肌力及下肢左右同名肌存在一定的差异,且这种差异对篮球运动员双脚同时起跳时的弹跳力有相当大的影响。     

对运用负重法提高篮、排球运动员弹跳力的研究

采用文献资料法、实验法等方法对篮球、排球运动员的弹跳力进行了实验研究，发现采用踝关节负重法可以较快提高篮、排球运动员的弹跳力且可以节约训练时间、提高训练效率。     

Measurements of the horizontal and vertical speeds of tennis courts

Tennis courts are normally classified as fast or slow depending on whether the coefficient of sliding friction (COF) between the ball and the surface is respectively small or large. This classification is based on the fact that the change in horizontal ball speed is directly proportional to the COF if the ball is incident at a small angle to the horizontal. At angles of incidence greater than about 16° it is commonly assumed that the ball will roll during the bounce, in which case one can show that the ratio of the horizontal speed after the bounce to that before the bounce will be 0.645 regardless of the angle of incidence or the speed of the court. Measurements are presented showing that (a) at high angles of incidence, tennis balls grip or ‘bite’ the court but they do not roll during the bounce, (b) the bounce:speed ratio can be as low as 0.4 on some courts and (c) the normal reaction force acts through a point ahead of the centre of mass. An interesting consequence is that, if court A is faster than court B at low angles of incidence, then A is not necessarily faster than B at high angles of incidence. An exception is a clay court which remains slow at all angles of incidence. The measurements also show that the coefficient of restitution for a tennis ball can be as high as 0.9 for an oblique bounce on a slow court, meaning that the ball bounces like a superball in the vertical direction and that slow courts are fast in the vertical direction.     

Oblique impact of a tennis ball on the strings of a tennis racket

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.