Differences in pedalling technique between road cyclists of different competitive levels     

Juan García-López  Sergio Díez-Leal  Ana Ogueta-Alday  Josu Larrazabal  José A. Rodríguez-Marroyo 《Journal of sports sciences》2016,34(17):1619-1626

The purpose of this study was to compare the pedalling technique in road cyclists of different competitive levels. Eleven professional, thirteen elite and fourteen club cyclists were assessed at the beginning of their competition season. Cyclists’ anthropometric characteristics and bike measurements were recorded. Three sets of pedalling (200, 250 and 300 W) on a cycle ergometer that simulated their habitual cycling posture were performed at a constant cadence (~90 rpm), while kinetic and kinematic variables were registered. The results showed no differences on the main anthropometric variables and bike measurements. Professional cyclists obtained higher positive impulse proportion (1.5–3.3% and P < 0.05), mainly due to a lower resistive torque during the upstroke (15.4–28.7% and P < 0.05). They also showed a higher ankle range of movement (ROM, 1.1–4.0° and P < 0.05). Significant correlations (P < 0.05) were found between the cyclists’ body mass and the kinetic variables of pedalling: positive impulse proportion (r = ?0.59 to ?0.61), minimum (r = ?0.59 to ?0.63) and maximum torques (r = 0.35–0.47). In conclusion, professional cyclists had better pedalling technique than elite and club cyclists, because they opted for enhancing pulling force at the recovery phase to sustain the same power output. This technique depended on cycling experience and level of expertise.  相似文献   

浅谈实践环节在教学过程中的重要性   总被引：3，自引：0，他引：3  

黄娟 《高教论坛》2002,(5):83-84

从实践教学和理论教学的特点出发，通过分析两者间的关系，论述了实践教学在教学改革过程中的重要性，并指出教学过程中两者应相辅相成、取长补短。  相似文献   

基于Pro/E的直齿锥齿轮Program参数化造型     

Pei Zhiming) Xu Juan) Lv Huiming) 《石家庄铁路工程职业技术学院学报》2007,(3)

介绍Pro/Engineer的Program参数化造型方法及其程序结构,并且以直齿锥齿轮为实例,详细地介绍Program参数化造型的实现过程。为同类产品实现参数化造型,减少重复劳动,提高设计效率提供一种适用、有效的方法。  相似文献   

由“河堤决口了,洪水冲过来了”说开去     

郑方  李娟 《新乡师范高等专科学校学报》2007,21(3):106-107

复句中的语义关系既是事物之间客观联系的反映,又是人们主观视角的反映。在事物之间的客观联系保持固定的情况下,人们的主观视角会随着认知需求的变化而变化。表现在复句中,则是适时添加复句关系词。并列范畴转化为因果范畴是人的特定视角的转化,这需要一定的客观条件,同时又必须有一定的认知作为前提。  相似文献   

The kinematic differences between off-spin and leg-spin bowling in cricket     

Aaron J. Beach  René E. D. Ferdinands  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):295-313

Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.  相似文献   

Perceived health problems in swimmers according to the chemical treatment of water in swimming pools     

Álvaro Fernández-Luna  Pablo Burillo  José Luis Felipe  Julio del Corral  Jorge García-Unanue  Leonor Gallardo 《European Journal of Sport Science》2016,16(2):256-265

The objective of this study was to determine which chemical treatment used for disinfecting water in indoor swimming pools had the least impact on users' perceptions of health problems, and which generated the greatest satisfaction with the quality of the water. A survey on satisfaction and perceived health problems was given to 1001 users at 20 indoor swimming pools which used different water treatment methods [chlorine, bromine, ozone, ultraviolet lamps (UV) and salt electrolysis]. The findings suggest that there is a greater probability of perceived health problems, such as eye and skin irritation, respiratory problems and skin dryness, in swimming pools treated with chlorine than in swimming pools using other chemical treatment methods. Pools treated with bromine have similar, although slightly better, results. Other factors, such as age, gender, time of day of use (morning and afternoon) and type of user (competitive and recreational), can also affect the probability of suffering health problems. For all of the above, using combined treatment methods as ozone and UV, or salt electrolysis produces a lower probability of perceived health problems and greater satisfaction.  相似文献   

试论健美操运动对校园体育文化的影响     

屈德新  李宏印  邱娟 《山西广播电视大学学报》2007,12(5):28-29

本文从健美操与校园体育文化两者的功能出发,探讨两者之间的关系。研究表明,健美操作为当代高校一种新兴的校园体育活动,不仅丰富了校园体育文化的内涵,同时对整个校园体育文化的发展方向和结构布局均有着重要的影响。反之,丰富多彩的校园体育文化活动是健美操运动赖以生存和发展的基础,两者相互依赖,相互促进,共同发展。  相似文献   

李清照作品的女性特色     

徐娟 《黑龙江教育学院学报》2007,26(2):93-95

李清照是中国文学史上创造力最强、艺术成就最高的女性作家。综观李清照的作品,不仅题材丰富,其体裁更可谓诗词文赋兼擅,欢愉之作亦工,悲苦之篇尤胜。李清照作品的多姿多采,是其饱尝人间甘苦的人生所决定的。她的词不论是写少女的天真活泼,还是写少妇的相思、幽怨,抑或写老年嫠妇的凄苦境遇,无不表现出一种与众不同的情趣和韵味,令人回味无穷。她词作中所展现的女性情感世界,完美的艺术技巧,充分展示了其个性,揭示了女性生活中婉美、多情的一面,而且以其不同时期的作品,构成了一部女性情感历程的巨著。  相似文献   

带式输送机虚拟实验系统在教学实际中的应用     

寇子明  张展宁  李军霞  梁绍伟  杨丽凤  吴娟  高贵军 《教育教学论坛》2019,(3):122-123

带式输送机有着非常复杂但很有效的结构和电液控制系统,如果在教学中加入对于这一环节的学习与研究,对于培养出全面的工程型人才能够起到非常关键的作用。结合目前的教学实践需求,提出了带式输送机的模拟实验系统和基于Automation Studio的虚拟实验系统。这两种系统能够让学生全面了解带式输送机的结构及其工作原理,也解决了教师的教学中缺乏实践环节的困扰。  相似文献   

高校招生中“加分降线投档”政策之分析     

王娟 《湖北招生考试》2006,(16)

“享受加分考生名单、录取结果要公示”,是高校招生要实现公开、公平与公正政策的表现之一。从公共政策和理性的视角审视,“加分降线投档”政策是政府为了解决招生过程中出现的特殊群体问题而制定的具体政策,具有公共政策的特质,对教育行动具有导向作用；该政策也是人们充分运用理性的结果,既能体现工具理性,也虑及价值平衡问题,给价值理性留有一定空间。  相似文献