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Salo A Bezodis I 《Sports biomechanics / International Society of Biomechanics in Sports》2004,3(1):43-53
The purpose of this study was to further understand the biomechanical differences between the standing and crouch starting methods, and to investigate whether one of the starting styles provides better acceleration and proves to be faster. Six university track team sprinters performed 2 x 3 x 50 m trials. Digitised video, photocell timing, and velocity data revealed that during the first steps of the performance the standing start produced higher body centre of mass horizontal velocity than the crouch start. This may be due to the longer distance between the feet in the standing start, which caused longer push-off phases, and the work against gravity in the crouch start. However, this advantage in horizontal velocity disappeared by the 10 m mark, where similar velocities were recorded with both start styles. Further, there was no statistically significant difference between the two starting styles in horizontal velocity at the 25 m mark, nor in the time to reach the 25 m or 50 m mark. Regarding relay running, where athletes need to decide to adopt either a crouch start without starting blocks or a standing start, there seems to be no specific reason for outgoing athletes to use a crouch start, although this area warrants further investigation. 相似文献
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Elizabeth J. Bradshaw Peter S. Maulder Justin W.L. Keogh 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):246-260
In the current study, we quantified biological movement variability on the start and early acceleration phase of sprinting. Ten male athletes aged 17–23 years (100-m personal best: 10.87 ± 0.36 s) performed four 10-m sprints. Two 250-Hz cameras recorded the sagittal plane action to obtain the two-dimensional kinematics of the block start and initial strides from subsequent manually digitized APAS motion analysis. Infra-red timing lights (80 Hz) were used to measure the 10-m sprinting times. The coefficient of variation (CV%) calculation was adjusted to separate biological movement variability (BCV%) from estimates of variability induced by technological error (SEM%) for each individual sprinter and measure. Pearson's product–moment correlation and linear regression analysis were used to establish relationships between measures of BCV% and 10-m sprint start performance (best 10-m time) or 10-m sprint start performance consistency (10-m time BCV%) using SPSS version 12.0. Measurement error markedly inflated traditional measures of movement variability (CV%) by up to 72%. Variability in task outcome measures was considerably lower than that observed in joint rotation velocities. Consistent generation of high horizontal velocity out of the blocks led to more stable and faster starting strides. 相似文献
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本次世锦赛竞技游泳项目将要产生的第一金就是男子400米自由泳。虽然是世界游泳锦标赛,但该项目更像是一场亚洲之战,将有两名中国选手登场,分别是2008年奥运会男子400米自由泳项目的银牌得主张琳,与中国的后起之秀、从亚运会开始吸引了全世界专业游泳运动员关注的小将孙杨。他们的主要对手是同是亚洲人的朴泰桓。 相似文献
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Karla de Jesus Kelly de Jesus J. Arturo Abraldes Alexandre Igor Araripe Medeiros Ricardo J. Fernandes João Paulo Vilas-Boas 《Journal of sports sciences》2016,34(9):871-877
We aimed to analyse the handgrip positioning and the wedge effects on the backstroke start performance and technique. Ten swimmers completed randomly eight 15 m backstroke starts (four with hands on highest horizontal and four on vertical handgrip) performed with and without wedge. One surface and one underwater camera recorded kinematic data. Standardised mean difference (SMD) and 95% confidence intervals (CI) were used. Handgrip positioning did not affect kinematics with and without wedge use. Handgrips horizontally positioned and feet over wedge displayed greater knee angular velocity than without it (SMD = ?0.82; 95% CI: ?1.56, ?0.08). Hands vertically positioned and feet over wedge presented greater take-off angle (SMD = ?0.81; 95% CI: ?1.55, ?0.07), centre of mass (CM) vertical positioning at first water contact (SMD = ?0.97; 95% CI: ?1.87, ?0.07) and CM vertical velocity at CM immersion (SMD = 1.03; 95% CI: 0.08, 1.98) when comparing without wedge use. Swimmers extended the hip previous to the knee and ankle joints, except for the variant with hands vertically positioned without wedge (SMD = 0.75; 95% CI: ?0.03, 1.53). Swimmers should preserve biomechanical advantages achieved during flight with variant with hands vertically positioned and wedge throughout entry and underwater phase. 相似文献
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Ricardo Peterson Silveira Pro Stergiou Pedro Figueiredo Flávio de S. Castro Larry Katz Darren J. Stefanyshyn 《European Journal of Sport Science》2018,18(10):1317-1326
The aim of this study was to determine the biomechanical parameters that explain ventral start performance in swimming. For this purpose, 13 elite swimmers performed different variants of the ventral start technique. Two-dimensional video analyses of the aerial and underwater phases were used to assess 16 kinematic parameters from the starting signal to 5?m, and an instrumented starting block was used to assess kinetic data. A Lasso regression was used to reduce the number of parameters, providing the main determinants to starting performance, revealing different combinations of key determinants, depending on the variant (r²?≥?0.90), with flight distance being the most relevant to all variants (r?≤??0.80; p?r?=??0.79; p?r?≤?0.61; p?r²?=?0.66) or block time and flight distance (r²?=?0.83). These data provide relevant contributions to the further understanding of the biomechanics of swimming starts as well as insights for performance analysis and targeted interventions to improve athlete performance. 相似文献
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发言1 历史上真正称得上“王朝”的只有三支球队:40年代末至50年代中期的明尼阿波利斯湖人队,领衔人物是NBA历史上第一位超级中锋迈肯,他们在6年内拿了5次冠军;50年代末至60年代末的波士顿凯尔特人队,他们在13年中拿了11次冠军,头号明星是拉塞尔;90年代的芝加哥公牛队,乔丹率领他们在8年内获得6次冠军。即便是80年代的洛杉矶湖人队,虽然在帕特莱利手下5夺冠军,但由于他们从未获得过“三连冠”,在同一时代还有一支伟大的凯尔特人队,所以那时的湖人也只是与凯尔特人并列,被称为“黑白双雄”时代。 相似文献
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无机胶水的普及无疑给器材界彻彻底底洗了个牌。有机时代由于可以借助胶水的膨胀增弹作用,能提供足够的杀伤力。只要能一板定乾坤则无需连续。而无机的降速作用,在很大程度上相对限制了装备的单板杀伤力。随着无机进程的深入,器材的进化走向了一种“能攻、亦要能守”的趋势。均衡全面,才是如今的制胜之道。 相似文献
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世界在那边──哥伦布就像’94美国之夏马拉多纳的黯然离去一样,没有人能跨越时代.马拉多纳的时代结束了,他就要退出这个舞台,无论他是球王还是天神。中国足球也面临着一个时代的终结．我们不得不面对这样一个现实。以范志毅、郝海东、徐弘为代表的这一代中国球员已完成了他们的历史使命,时间将永恒的定格在1997年那个寒冷的10月。我们没在任何理由怀疑他们的状态和运动生命,但毫无颖问的是下一个世界杯赛2002年时,命运将不会垂青这些今已风头劲出的英雄人物。中国足球需要一次世界杯的洗礼来卸掉身上沉重的包袱,求得一种精神上的解脱… 相似文献
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2000年欧洲杯上基冈调教的英格兰队一败涂地,小组赛后便饮恨踏上归途,而且被罗马尼亚队教练评论为“踢的是上古时期的足球”。当时一些媒体甚至悲观地认为“跟上潮流、彻底转变风格需要一代人的努力”。基冈离任已是不可避免,颇受球迷爱戴的维纳布尔斯接任呼声极高,而且虽然与足总有隙,这位大众眼中的“俊妞甜姐”仍跃跃欲试,他向《每日邮报》独 相似文献
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今年WCG最大的革命是首次引入了格斗游戏(FTG)项目,作为当前家用游戏机3D格斗游戏代表之一的《Dead or Alive》意外的成为幸运儿。由于格斗游戏的起源和竞技化几乎都离不开大型街机机体和街机游戏．所以此次WCG选择XBOX上的《DOA 2：Ultimate》(中译《生死格斗2：终极版》,以下简称DOAU 2)也让广大格斗游戏玩家大惑不解。 相似文献
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在1998～1999赛季中,意大利20支乙级队经过38轮的厮杀后,维罗纳队、都灵队、莱切队和雷吉纳队最终脱颖而出,升入甲级。值得一提的是雷吉纳队,他是首次杀人甲级队,成为亚平宁足坛最年轻的甲级球队。主教练科隆巴说:“皮亚琴察队的经验对我们是至关重要的,珍惜这次升级的机会。只要在甲级队中稳扎稳打,我想保级不是本可能的”。 相似文献