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The development of peak performances is a main research focus in sports science. It is unclear how many former top junior athletes achieve success in the elite class later. The aim of the present study was to examine the careers of athletes who participated in major junior or adult/elite cycling events using prospective and retrospective analysis of competition results. The official results of major junior (age < or = 18 years) and elite (age > 18 years) cycling races from 1980 to 2004 were analysed. Age-related aspects, career lengths, and success were compared between riders who presented results in both junior and elite races (JUNIOR ELITE) and riders who had no junior race results (ELITE ONLY). Altogether, 27,454 results of 8004 athletes from 108 countries were collected. We found that 29.4% of the elite athletes had participated in junior World Championships, and that 34% of the participants in junior World Championships later participated in major elite competitions. JUNIOR ELITE athletes are significantly more successful in several cycling disciplines and have their first and last elite result at a younger age than ELITE ONLY athletes. No difference was found in career lengths. The data presented here emphasize the importance of long-term training programmes in the development of peak performance in cycling. 相似文献
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A Jun 《中外文化交流(英文版)》2006,(12):26-27
＂In the early springime, burgeoning flowers look more beautiful in the caress of gentle breeze and against brightness of the pure moon. Ancient beauties, either slim or plump, look gloomier under shining stars... ＂ That is a line from the poem Shi Yue has written. She set the poem to music and named the composition ＂Charm of Strings＂. Shi Yue learned music composition as an optional course for one year when she studied in Central Conservatory of Music and got best performance in composition analysis and harmony. ＂I had highest examination scores in my class. They are quite helpful to my music creation later,＂ Shi said. 相似文献
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Efthimiadou A Asimakopoulos B Nikolettos N Giatromanolaki A Sivridis E Lialiaris TS Papachristou DN Kontoleon E 《Journal of sports sciences》2006,24(8):849-854
Although angiogenetic therapy using recombinant growth factors holds much hope for the treatment of ischaemic diseases, there are still many unanswered questions, including the method of administration, the correct dose of these factors, and the duration of the therapeutic approach. Exercise has also been suggested to induce neovascularizaiton in muscles. We evaluated the angiogenetic effects of the intramuscular administration of basic-fibroblast growth factor (b-FGF) and acidic-fibroblast growth factor (a-FGF) in rat heart, compared with rats who exercised daily. In conclusion, both the intramuscular administration of b-FGF and exercise increased significantly angiogenesis in the heart in contrast to the intramuscular administration of a-FGF, which was ineffective. 相似文献
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The aims of this study were to investigate the energy build-up and dissipation mechanisms associated with using an arm swing in submaximal and maximal vertical jumping and to establish the energy benefit of this arm swing. Twenty adult males were asked to perform a series of submaximal and maximal vertical jumps while using an arm swing. Force, motion and electromyographic data were recorded during each performance and used to compute a range of kinematic and kinetic variables, including ankle, knee, hip, shoulder and elbow joint powers and work done. It was found that the energy benefit of using an arm swing appears to be closely related to the maximum kinetic energy of the arms during their downswing, and increases as jump height increases. As jump height increases, energy in the arms is built up by a greater range of motion at the shoulder and greater effort of the shoulder and elbow muscles but, as jump height approaches maximum, these sources are supplemented by energy supplied by the trunk due to its earlier extension in the movement. The kinetic energy developed by the arms is used to increase their potential energy at take-off but also to store and return energy from the lower limbs and to "pull" on the rest of the body. These latter two mechanisms become more important as jump height increases with the pull being the more important of the two. We conclude that an arm swing contributes to jump performance in submaximal as well as maximal jumping but the energy generation and dissipation sources change as performance approaches maximum. 相似文献
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内分泌学是研究细胞联络的科学,其领域是探求细胞之间或细胞自身影响的方式。细胞间联系必须有一种传递或信使分子,它由分泌细胞产生并通过体液输送至靶细胞,包括4种主要联络系统:神经、神经内分泌、内分泌和免疫系统。每个系统都能影响和控制另一系统的某些机能,反之,又接受被它所影响系统的调节和指令,因此,它们是高度综合和互相关联的,也反映其进化源十分接近。经典的血液 相似文献
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