Physiological and biomechanical responses between seated and standing positions during distance‑based uphill time trials in elite cyclists

Cyclists regularly change from a seated to a standing position when the gradient increases during uphill cycling. The aim of this study was to analyse the physiological and biomechanical responses between seated and standing positions during distance-based uphill time trials in elite cyclists. Thirteen elite cyclists completed two testing sessions that included an incremental-specific cycling test on a cycle ergometer to determine VO_2max and three distance-based uphill time trials in the field to determine physiological and biomechanical variables. The change from seated to standing position did not influence physiological variables. However, power output was increased by 12.6% in standing position when compared with seated position, whereas speed was similar between the two positions. That involved a significant increase in mechanical cost and tangential force (F_tang) on the pedal (+19% and +22.4%, respectively) and a decrease (?8%) in the pedalling cadence. Additionally, cyclists spent 22.4% of their time in the standing position during the climbing time trials. Our findings showed that cyclists alternated between seated and standing positions in order to maintain a constant speed by adjusting the balance between pedalling cadence and F_tang.     

Sprint and jump performances do not determine the promotion to professional elite soccer in Spain, 1994–2012

ABSTRACT

The aims of this study are (a) to describe the evolution of neuromuscular performance over an 18 year period within a Spanish elite reserve team; (b) to check if there were any relation between the playing position and sprint and jump performances and (c) to look into the alleged impact of this factor on the top playing level attained by the soccer players. We considered the physical tests (5 m and 15 m sprint times and countermovement jump (CMJ) height) made by 235 players enrolled in the reserve team of the Club from 1994 to 2012 and the highest competitive-level they achieved: Spanish first (n = 39) and second divisions (n = 36) and semi-professional (n = 160). Furthermore, the players were classified according to their playing positions. The main findings were a very-likely/most-likely lower neuromuscular performance (ES = 0.48–0.68, small to moderate) in the last six-season term (2006–2012) than in the first term (1994–2000); possibly/very-likely lower performances in sprinting and CMJ (ES = 0.22–0.55, small) by central defenders (CDs) and midfielders than by other playing positions; very-likely better performances in sprinting and jumping by first and second divisions central defenders than by semi-professional central defenders (ES = 0.90–1.02, moderate). Sprint and jump performances are not a relevant physical parameter to promote to the top level of soccer in Spain except for one in six of the playing positions: CDs.     

男子排球高姿防守准备姿势的运动学分析

现代排球比赛中 ,低姿防守技术动作为高姿防守技术动作所替代。采用常速摄像方法 ,运用上海体育学院与复旦大学 (1994～ 1996 )联合研制的运动生物力学计算机辅助分析CAA与教学CAI系统进行解析。在实验室条件下 ,通过对复旦大学部分男子排球运动员后防时采取的高、低两种不同准备姿势 ,滚翻救球、侧向救球、脚踢球等不同的击球技术动作、向右移动过程的实测 ,并对其结果进行对比分析研究 ,探讨高姿防守准备姿势的适用条件 ,为正确指导该技术的训练工作提供可参考的理论依据。     

试论现代篮球中锋投篮技术

现代篮球中锋的投篮技术是一项强对抗的进攻组合技术。它是由抢位、接球和投篮组成的,它的运用主要体现在意识和抢位的对抗性、接球的攻击性和投篮的应变性     

篮球运动阵地进攻体系结构的再认识

阵地进攻,在篮球进攻整体系统中占有非常重要的地位,采用观察统计法、逻辑分析法等研究方法,对篮球阵地进攻体系结构进行分析,研究表明:阵地进攻是由比赛队员的各种个体进攻,不同区域上2～3名队员之间的小组配合进攻,以及在这两者基础之上的全队整体战术进攻三方面共同构成的;三者之间是一种相互依赖、相互联系同时又相对独立的辩证关系;三者作为基本的组成要素,以它们之间的各种有机联系为基础,并以特定的结构构成一种具有整体功能的阵地进攻系统.     

CBA篮球运动员位置技术特征及指标体系分析

采用文献资料法、问卷调查法、录像观察法、数理统计法、逻辑分析法,以参加2002-2003赛季CBA甲A联赛半决赛、决赛的球员为研究对象,对球员场上的竞技表现进行了较系统的研究.研究结果:筛选出各位置特征的3项判别指标为:协助摆脱、威胁位置获球、威胁传球;构建了球员竞技表现评价指标体系.     

体育院校大学语文教学改革的研究与探索

随着中国体育文化事业的蓬勃发展和2008年北京奥运会的临近,体育事业的可持续发展战略愈来愈需要体育人具有高水平的“母语思维与写作”能力,而大学语文为体育人提供必须的母语思维和文字表达能力。所以,克服体育院校“语文学科”身小力薄等种种困难,“以体为本,为体服务”的运动专业语文教材建设迫在眉睫。     

财经媒体的市场定位与营销策略

本文对国内不同类型财经报纸的市场定位作了比较分析,并对财经报纸发展至为关键的营销策略作了探讨.     

对普通高校不同职称公体课教师专业能力自我评价的比较分析

本文采用国际上公认的量表分析模式,从体育教学的医学与法律、人类生长与发展、体育教学的心理与社会、体育教学的生物与生理、体育教学的理论与技巧和体育教学实践六个方面对普通高校不同职称公体课教师的专业能力进行比较分析,以考察他们在专业能力方面自我评价的特卢、和差异性。     

最后用力阶段非投掷臂对投掷成绩影响的比较研究

通过对33名学生的铅球、标抢、铁饼在最后用力阶段非投掷臂的大幅度摆动成绩与小幅度摆动成绩的实施研究,为提高投掷技术的教学质量、训练成效提供理论和实践依据,研究结果表明：非投掷臂在最后用力阶段的正确摆动姿势对投掷成绩有显著的影响;实验组的成绩比对照组的成绩因性别、项目的不同可提高6％～22％;铁饼成绩提高最显著,其次为标枪、铅球。