An analysis of selected kinematic variables in national and elite male and female 100-m and 200-m breaststroke swimmers

The kinematic analysis of competition breaststroke swimming has tended to focus on the mean values of swimming speed, stroke rate and stroke length; values in individual lengths, as well as the start, turns and finish, have largely been ignored. This study includes all such variables and aims to improve the coach's holistic understanding of breaststroke racing by determining the relationships and diff erences between and within these selected kinematic variables. We also compare 100-m events with 200-m events to determine if there are characteristic diff erences between them. Competitive breaststroke swimming performances in 100-m events (males: n = 159, finishing time = 65.05 - 2.62 s; females: n = 158, finishing time = 74.04 - 3.66 s) and 200-m events (males: n = 159, finishing time = 141.47 - 6.15 s; females: n = 158, finishing time = 158.66 - 7.87 s) were collected and analysed from 12 world, international and national championships. The better 100-m and 200-m breaststroke swimmers were found to demonstrate greater competency in the kinematic variables measured, except stroke kinematics, which were unique to each individual. These findings suggest that coaches should place emphasis on all of the kinematic components in training and that they should attempt to identify the stroke rate to stroke length ratio most appropriate for the individual. Finally, characteristic diff erences do exist between the 100-m and 200-m events, which has implications for how swimmers might train for each event.     

An analysis of selected kinematic variables in national and elite male and female 100-m and 200-m breaststroke swimmers

The kinematic analysis of competition breaststroke swimming has tended to focus on the mean values of swimming speed, stroke rate and stroke length; values in individual lengths, as well as the start, turns and finish, have largely been ignored. This study includes all such variables and aims to improve the coach's holistic understanding of breaststroke racing by determining the relationships and differences between and within these selected kinematic variables. We also compare 100-m events with 200-m events to determine if there are characteristic differences between them. Competitive breaststroke swimming performances in 100-m events (males: n = 159, finishing time = 65.05 +/- 2.62 s; females: n = 158, finishing time = 74.04 +/- 3.66 s) and 200-m events (males: n = 159, finishing time = 141.47 +/- 6.15 s; females: n = 158, finishing time = 158.66 +/- 7.87 s) were collected and analysed from 12 world, international and national championships. The better 100-m and 200-m breaststroke swimmers were found to demonstrate greater competency in the kinematic variables measured, except stroke kinematics, which were unique to each individual. These findings suggest that coaches should place emphasis on all of the kinematic components in training and that they should attempt to identify the stroke rate to stroke length ratio most appropriate for the individual. Finally, characteristic differences do exist between the 100-m and 200-m events, which has implications for how swimmers might train for each event.     

2004年全国跆拳道冠军赛技战术运用情况的调查分析

对参加2004年全国跆拳道冠军赛中运动员的技术使用情况进行调查分析。结果表明,横踢技术应用单一的问题依然存在,而且其得分率较低;击头技术的发展明显停滞不前;侧踢技术击头使用不多,但效果较好。     

从2006年第39届世界体操锦标赛分析北京奥运会我国男子体操实力

以39届世界体操锦标赛男子运动员以及比赛成绩为研究对象,通过文献法、观察法、数理统计和比较法对相关资料进行归纳、对比和分析,了解当今世界男子竞技体操发展状况,旨在为我国男子竞技体操保持优势地位,为备战2008年北京奥运会提供理论参考.     

The effect of critical speed and exercise intensity on stroke phase duration and bilateral asymmetry in 200-m front crawl swimming

The main aim of this study was to determine the absolute temporal relationship between the power and recovery phases of the stroke cycle in front crawl swimming in response to progressive changes in exercise intensity that occurred before and after critical speed. A second objective was to determine whether intensity-related changes in the power/recovery phase relationship affects the bilateral symmetry of the stroke. Stroke parameters were recorded for each 25-m length during a progressive 200-m interval training set, in which eight (2 males, 6 females) national-level swimmers swam at intensities below, above, and at critical speed. The results demonstrated that substantial increases in stroke rate (P < 0.01) occurred at critical speed, and that these increases were related to a greater decrease in the duration of the power phase than the recovery phase (P < 0.01). The results also show that the degree of bilateral asymmetry was greater for the power phase than the recovery phase, and was inversely related to intensity in both phases of the stroke cycle. The findings of this study suggest that critical speed-related increases in stroke rate are an indirect consequence of increased force production in the power phase of the stroke, and that bilateral asymmetry is both intensity- and stroke-phase dependent.     

从第37届世界体操锦标赛看雅典奥运会我国男子实力

通过调查访问.录像观察和文献资料等方法,对37届世界体操锦标赛男子团体决赛前8名队,全能决赛前8名运动员及各单项决赛前3名运动员的成绩,动作难度和完成情况进行研究。笔者认为,中国队在2004年雅典奥运会上有望实现4枚金牌的目标。     

Asymmetry in elite rowers: effect of ergometer design and stroke rate

Between limb movement asymmetries and foot force production asymmetries are thought to be detrimental for both rower's performance and risk of injury, particularly when rowing frequently on ergometers. Several ergometers with different designs can be used by rowers as part of their indoor training. Hence, this study aimed to compare asymmetries in lower limb joint kinematics and foot force production with respect to ergometer design and rowing intensity. A new symmetry index was proposed to assess these asymmetries in elite rowers during a test on three ergometers. Additionally, the asymmetry in lower limb length was assessed to investigate its relationship with kinematic and kinetic asymmetries. Parameters describing medium (5–10%) or high (>10%) asymmetries were compared between rowing ergometers and intensities. Results indicated medium asymmetries for the ankle joint angle and hip–knee joint accelerations and high asymmetries for the resultant force and the ankle joint acceleration associated with a low inter-stroke variability. Kinetic asymmetry was neither correlated to kinematic asymmetry nor with lower limb length asymmetry. The use of a mobile ergometer led to higher joint acceleration asymmetries. Further studies are necessary to investigate the relation between these findings and muscular adaptations that may increase the risk of lower-back injury.     

2004年雅典奥运会中国夺金项目失分因素及对策分析

针对2004年雅典奥运会上中国体育代表团个别夺金项目的失分现象,从多方面进行了主、客观因素的分析．指出导致中国夺金项目失分的深层因素是日益严重的竞技体育功利化发展趋势,“举国体制’’和“奥运战略,,是中国奥运体育代表团成功的保障同时也是其巨大压力的根源。面对2008年北京奥运会,提出了科学规划奥运奖励机制等相关对策与建议。     

我国优秀女子跳远运动员摆动腿在助跑与起跳阶段的运动学诊断

运用灵像解析的方法对8名中国女子跳远运动员（平均成绩6．29m）和10名美国运动员（平均成绩6．52m）有关运动学参数进行对比、诊断。研究表明，我国优秀女子跳远运动员摆动腿在助跑最后一步蹬伸阶段的伸髋平均水平速度和着板时摆动角速度两项指标上有一定的不足；在助跑最后一步中，摆动腿放脚速度慢，髋关节前送技术差，导致摆动腿支撑扇角较大，这是我国运动员在此阶段不能保持较高水平速度的直接原因；在助跑最后一步蹬伸阶段中，由于摆动腿离地时的膝角较大，“屈蹬”技术形成的不够理想，推迟了我国运动员摆动的时机；在着板时，我国运动员应主动积极地加快摆动腿的摆动，以此带动起跳脚脚掌向后的加速踏板动作，同时努力使着板角达到费尔歇模式；起跳过程的缓冲阶段是获得垂直速度的主要阶段，加快摆动腿的摆动速度是损失较小水平速度、获得较大垂直速度的有效途径。     

我国女子跳马技术现状与对策

通过对39、40届世界体操锦标赛,雅典、北京奥运会女子跳马决赛运动员动作的类型、难度、完成质量与成绩关系的研究和对北京奥运会中、美女子跳马相关数据的对比分析,认为中国运动员选用的动作单一,整体难度和完成动作的质量上还与美国队存在差距。提出了转变训练思想、加强基础体能训练并力求创新等对策,如把“以强带弱”改为“以弱促强”;充分利用规则和器械特点找准技术突破口;加强速度和力量素质训练;发展适合我国运动员身体特点的动作,提高动作起评分等。     

Competitive balance trends in elite table tennis: the Olympic Games and World Championships 1988-2016

ABSTRACT

Competitive balance is important because it enhances outcome uncertainty and therefore it promotes spectator interest, and encourages government investment in a sport. This article analyses the distribution of gold medals, medals, medal points and top eight points amongst nations in table tennis from 1988 to 2016 at the Olympic Games and the World Championships respectively. A normalised version of the Herfindahl-Hirschman Index and a coefficient of variation are calculated for each nation’s share of these performance indicators. The key findings are that China dominates both events, with successful female players being more dominant than their male counterparts. The competitive balance for gold medals has declined, whilst there is a trend towards improved competitive balance for top eight points for women, suggesting that more teams are featuring in the top eight (but not necessarily the top three) placings. This research has implications for the development of table tennis competitions. Compared to other racket sports, the issue of competitive imbalance in table tennis is particularly thorny, which threatens the long-term development of this sport. Accordingly, some measures are recommended for the International Olympic Committee and the International Table Tennis Federation to propel a more balanced development of international table tennis.