标准400米田径场第二种抢道标志线设计方案

目前所用的抢道标志线(下称第一种抢道线)是一条弧线,位于第二直曲段分界线处,要以第二直曲段分界线为基准才便于准确画出。若以第二直曲段分界线本身为抢道标志线(下称第二种抢道线),其设计、计算和画法就更为简单。第二种抢道线的设计和计算。如图一所示,三角形AB C是直角三角形,线段b是第二直曲段分界线,同时也是抢道标志线。线段c是外道运动员的最短抢道路线。用勾股定理将     

仿渐伸线抢道标志线之计算丈量划线法

田径规则规定圆弧抢道标志线丈量划线法(见图一、图二),以分三线上实跑线之分界点C′为争夺点,即以C′点为园心,以直段之长85.96m作半径划圆弧B′B_9作为抢道标志线,据此再计算出各外道之切入差。也有人提出,以C′点为争夺点,以分二线作抢道标志线,据此再计算出各外道之切入差。我认为对以C′点作争夺点的论点来说,以上两种计算方法都是正确的。两者相比,前者优于后者,此乃常识,故不赘述。但实际上各外道切入内道之捷径均不经过C′点,如此就达不到各道全程捷径均相等。因此,我认为以C′点作争夺点的论点     

也谈铅球、链球、铁饼投掷区的划法

根据81年国家体委审定的《田径竞赛规则》规定,铅球、链球、铁饼投掷落地区40度角度线的划法应参照图一和表一数据;其具体划法应是;通过园心作场地的中轴线OM(如图二),在OM上截取OC为18.85米,以C点为园心,以6.86米为半径划弧。再以O点为园心,以20.06米为半径划弧相交于A,B两点,连结OA、OB并向外适当延长,即划出40度落地区。     

标枪在体育教学中的开发利用

一、充当其他体育器材 1．标志杆旗 在体育教学中有时需要旗杆作为标示。例如可做800米跑抢道标志;再如在比赛时用作彩旗;设置投掷项目安全区，用标枪插好，拉好线。     

应该重视过“抢道标志线”后的直线跑技术训练

田径竞赛规则规定800米、4×400米接力和4×200米接力赛跑在400米场地进行时,运动员应该在各自的分道上分别跑完一个弯道和三个弯道,并跑过抢道标志线后才可切入里道。有一些比赛在进行以上项目比赛时,发现出有些运动员通过抢道标志线后,往往不是沿着直线向200米第一道起点处跑进,而是急于抢进里道,沿折线跑进。尤其是基层中小学田径运动会,多数运动员都是如此,就是省级青少年田径运动会上,运动员这种跑折线的现象     

“抢道”要科学

８００米选手应掌握和运用规则,运动成绩的提高需要科学知识。 ８００米和 ４×４００米接力多跑一点儿距离,数字并不惊人。然而对那些只差一肩半步就能得第一名和那些只差零点几秒就可破纪录或达标的选手来说,那就是一个不小的数字了。因此,抢道方法应引起足够的重视。 一、抢道标志线的画法 ８００米和 ４ ×４００米接力跑都是先分道跑,然后不分道跑。运动员必须分道跑完所规定的弯道后,才能由外道向里道切入。标明跑完规定距离,可以开始切入里道的线叫抢道标志线。其具体画法有两种： （一）在第三直、曲段分界线上从跑道内突沿…     

不同周长田径场地计算与测绘

五、抢道标志线的画法、原理及计算标准场地800米、4×200米、4×400米,不标准场地400米,4×100米、4×200米、4×400米接力的赛跑,初段分道跑,过规定的弯道后各道运动员在画出的孤形限制处开始切入里道,这条限制线叫抢道标志线。各道运动员由弯道转入直道时切入里道所多跑的距离叫切入差。切入差数的计算公式是:切入差数=([(n-1)d-0.10]~2 直道长~2-直道长或切入差数=直道长-(直道长~2-[(n-1)d-0.10]~2))~(1/2) 1、抢道标志线的画法(图22) 在弯道进入直道的交界线上距离跑道内沿0.30米处取一点A,再在前方的直、弯道交界线上距离跑道内沿O.30米处取一点C,然后以B点为园心,以CA长(即直     

"抢道标志线"的3种划线法及"切入差"值--兼谈对国际田联《场地设施标准手册》"抢道标志线"划线位置的修改意见

"抢道标志线"的划线方法可分为3种等半径划线法、渐展弧划线法、垂直线划线法.在论述3种划线法的基础上,以标准400m径赛场地为例,列举了3种划线法的"切入差"值;分析了3种划线法的优缺点;指出了国际田联<田径场地设施标准手册>转载的瑞典田径联盟抢道标志线的划线法与计算方法之间存在的矛盾并提出了修正意见.对于第29届奥运会田径场地的计算与划线,必须在充分解读国际田联<田径场地设施标准手册>的基础上进行,不可囫囵吞枣、盲目照搬.     

赛艇划浆技术的运动学与动力学测试研究

本文对我国优秀赛艇运动员的划浆技术进行了实测研究。结果如下:①从船速曲线的研究中,提出了判断划浆技术的最大差、最小差、拉段差、推段差四个指标和单峰型与双峰型两种曲线类型。②研究结果指出:前后划浆角之比约为2∶1;划浆的前半段完成划浆力作功的80％以上。③对比了“平缓力型”和“爆发力型”两种划浆力曲线的差异。④我国优秀选手与世界水平选手的运动曲线相比过于扁平。⑤提出了将我国延用的“提—拉—按—推”四个划浆动作阶段改为“拉提—拉—拉按—推”。     

关于抢道线画法的探讨

本文通过运用数学原理计算,指出国内外现行田径规则中抢道线的画法使运动员的跑距不等。该文建议运用第二直曲段交界线为抢道线,把各道的切入差增加到起点前伸数中使各道运动员跑距相等的新画法。     

世界优秀女子500m速滑运动员全程速度节奏特征

目的：研究优秀女子速滑运动员全程速度节奏特征以快速提高我国该项目的运动成绩;方法：以荷兰短距离世锦赛比赛数据为基础,通过归纳总结和对比分析,研究女子内外道速度节奏特征。结果：女子外道的全程速度节奏特征是：第一直道快速加速,第一弯道稳定增速,第二直道缓慢增速后维持高速滑行,第二弯道大幅降速后维持原速滑行,第三直道调整后努力维持速度滑行;女子内道的全程速度节奏特征是：前100 m快速加速,112 m分段降低加速节奏,第一弯道保持速度稳定增长;出第一弯道后速度增长放慢,然后在入第二弯道前匀速前进;第二弯道仍然保持较稳定的速度节奏,出第二弯道后主动降速缓冲,然后努力维持高速滑行至终点;突出的最大速度能力和较好前100 m成绩是获取优异运动成绩的基础,但良好的全程速度节奏分配是获取好成绩的关键。     

The effects of wind and altitude in the 400-m sprint

In this paper I use a mathematical model to simulate the effect of wind and altitude on men's and women's 4400-m race performances. Both wind speed and direction were altered to calculate the effect on the velocity profile and the final time of the sprinter. The simulation shows that for a constant wind velocity, changing the wind direction can produce a large variation in the race time and velocity profile. A wind of velocity 2 m x s(-1) is generally a disadvantage to the 400-m runner but this is not so for all wind directions. Constant winds blowing from some directions can provide favourable conditions for the one-lap runner. Differences between the running lanes can be reduced or exaggerated depending on the wind direction. For example, a wind blowing behind the runner in the back straight increases the advantage of lane 8 over lane 1. Wind conditions can change the velocity profile and in some circumstances produce a maximum velocity much later than is evident in windless conditions. Lower air density at altitude produces a time advantage of around 0.06 s for men (0.07 s for women) for each 500-m increase in elevation.     

The effects of wind and altitude in the 400-m sprint

In this paper I use a mathematical model to simulate the effect of wind and altitude on men's and women's 400-m race performances. Both wind speed and direction were altered to calculate the effect on the velocity profile and the final time of the sprinter. The simulation shows that for a constant wind velocity, changing the wind direction can produce a large variation in the race time and velocity profile. A wind of velocity 2 m?·?s^?1 is generally a disadvantage to the 400-m runner but this is not so for all wind directions. Constant winds blowing from some directions can provide favourable conditions for the one-lap runner. Differences between the running lanes can be reduced or exaggerated depending on the wind direction. For example, a wind blowing behind the runner in the back straight increases the advantage of lane 8 over lane 1. Wind conditions can change the velocity profile and in some circumstances produce a maximum velocity much later than is evident in windless conditions. Lower air density at altitude produces a time advantage of around 0.06 s for men (0.07 s for women) for each 500-m increase in elevation.     

Lane bias in elite-level swimming competition

Performance outcomes at the 2013 World Swimming Championship were previously shown to be biased depending on the swimmer’s lane assignment. The purpose of this study was to determine if this kind of bias was unique, and if not, if the bias was related to the temporary or permanent nature of the pool. The effect of lane on the average odd-length split minus the preceding even-length split in the 800- and 1500-m freestyle events, and on the relative change from qualifying to preliminary performance in the 50-m events, was determined for 16 other elite-level competitions. Depending on the swimmers’ direction, split times were on average 0.16 s slower or faster in at least one lane at each of the 16 competitions, and in 49% of all lanes analysed. In 5 competitions, swimmers were shown to be faster in a majority of lanes in one direction as compared to the other. Analysis of the 50-m events at these 5 competitions indicate that preliminary performances were between 0.5 and 0.9% slower or faster than qualifying times, which is consistent with the direction effect observed in the distance freestyle events. Further, lane biases occur more often in temporary pools (70% of lanes) than in permanent pools (35% of lanes), with water currents as the most plausible cause. The prevalence of lane bias at elite-level swimming competition highlights the need for the implementation of policies and procedures to prevent such bias from occurring again in the future.     

Determination of football pitch locations from video footage and official pitch markings

The ability to determine a specific location on a football (soccer) pitch from television footage would provide a cost-effective method of obtaining competition-specific information on many professional and international teams. This study presents the accuracy and reliability of a new method of calculating ball location from simulated television coverage and known pitch markings. The coordinates of 99 markers of known location on a football pitch were digitized from video. An intersection point was determined from the equations of two lines that form pitch markings and the relationship from this point to other known pitch coordinates was calculated using a curve-fitting based method. Average error between known and reconstructed measures was 0.21 m for pitch width and 0.11 m for pitch length from a view simulating television coverage. Inter- and intra-rater reliability analyses showed researchers could consistently reconstruct pitch locations to within less than half a metre. The accuracy and reliability of this method will be sufficient for most practical uses in an applied sport environment, although the level of accuracy required will depend on the specific application. This method could be applied to other sports to determine specific locations on a pitch or court or to improve current competition analysis systems.     

中国体育用品制造业融资能力的变化及策略研究——以2008年金融危机为视角

自2008年由美国次贷危机引发的世界性金融危机以来,我国体育用品制造业的融资环境面临着三种变化:一是国内外两个消费市场的变化;二是民族贸易保护政策形成和国内金融制度缺失;三是社会资金流向与个体消费心理的变化。这三种变化对我国体育用品制造业融资能力产生了深刻影响:第一,原有的融资路径出现断裂;第二,新的融资渠道尚未开通;第三,已获得的融资外流迹象明显。基于此,本研究分析原有融资路径断裂的原因,揭示制约新的融资渠道形成的因素,剖析已有资金外流趋势,进而研究相应策略(市场策略、国家政策策略、资金管理与消费引导策略),为金融危机时期和经济回暖期我国体育用品制造业资金有效整合与供给提供建议。     

The influence of gate start position on physical performance and anxiety perception in expert BMX athletes

The critical importance of the start phase in bicycle motocross (BMX) racing is increasingly acknowledged. Past experiments underlined that the internal lane of the starting gate provides a strong positional advantage. However, how lane position affects start performance and cognitive and somatic state anxiety remains unexplored. We examined the start performance and anxiety responses of youth national-level BMX riders in both experimental and ecological contexts. We used contextualization motor imagery routines to evaluate start performance and state anxiety from the internal and external lanes. Cycle ergometer measures revealed a better start performance from the external lane, but we did not record any lane effect on actual gate start times. Both somatic and cognitive anxiety scores were higher before racing from the internal compared to the external lane. Finally, state anxiety (i.e., somatic anxiety, worry and concentration disruptions) negatively predicted the start performance. Present findings provide original insights on psychological factors involved in BMX start performance, and might contribute to fruitful coping interventions and training programmes in sports overlapping the framework of “handicap races” taking the specific form of positional advantages/disadvantages at the start (e.g., ski/snowboard cross, athletics, swimming, motorsports, etc.).     

学校开展游泳运动的冷思考

近年中国竞技游泳在国际舞台上从突破到多点开花,游泳也列入部分省市中考项目,为学校游泳的发展注入了强心剂,也标志着校园游泳建设即将驶入快车道。校园游泳热凸显,但其健康、可持续发展必定依靠成可操作、可落地、可监测、可评估的举措。研究认为校园游泳要坚持育人之本质;要坚持正确的角色和功能定位;应助力终生体育意识的养成;建设需强调教与学方式方法的创新与改革;发展要坚持思则变、变则通、通则达的理念。     

Kemp-Vincent Rally Test of Tennis Skill

Abstract

The Kemp-Vincent Rally Test of tennis skill was constructed to overcome the criticisms of available tennis skills tests. The major criticisms have been that current tests do not measure skills under game conditions, require the use of special equipment or line markings, and the time involved in their administration is prohibitive. In the Kemp-Vincent Rally Test the students rally as in a game situation, a relatively short time period is involved, and no special equipment or court markings are needed. The validity of the Kemp-Vincent Rally Test was found to be .84 for beginners and .93 for intermediate players when correlated with round robin tournament rankings. When validated against the Iowa revision of the Dyer test, the validity coefficient was .80. Test-retest reliability coefficients were .86 for beginners and .90 for intermediate players.     

Bend sprinting performance: new insights into the effect of running lane

Athletes in inner lanes may be disadvantaged during athletic sprint races containing a bend portion because of the tightness of the bend. We empirically investigated the veracity of modelled estimates of this disadvantage and the effect of running lane on selected kinematic variables. Three-dimensional video analysis was conducted on nine male athletes in lanes 8, 5 and 2 of the bend of an outdoor track (radii: 45.10, 41.41 and 37.72 m, respectively). There was over 2% (p < 0.05) reduction in mean race velocity from lane 8 (left step 9.56 ± 0.43 m/s, right step: 9.49 ± 0.41 m/s) to lane 5 (left step: 9.36 ± 0.51 m/s, right step: 9.30 ± 0.51 m/s), with only slight further reductions from lane 5 to lane 2 (left step: 9.34 ± 0.61 m/s, right step: 9.30 ± 0.63 m/s). Race velocity decreased mainly because of reductions in step frequency as radius decreased. These unique data demonstrate the extent of the disadvantage of inner lane allocation during competition may be greater than previously suspected. Variations in race velocity changes might indicate some athletes are better able to accommodate running at tighter radii than others, which should have implications for athletes’ training.