Effect of different loading conditions on running mechanics at different velocities     

Germán Carretero-Navarro  Doménico Cherubini  Wolfgang Taube 《European Journal of Sport Science》2019,19(5):595-602

Weighted vests are widely used to improve running economy and performance. However, it is not well-studied how running mechanics are adapted to counteract the higher peak vertical ground reaction forces (Fpeak) while running with such a device. Therefore, the present study aimed to investigate the effects of different loading conditions on running mechanics at different velocities. Thirteen subjects participated in two separate sessions one week apart. In the first session, maximal aerobic speed (MAS) was determined through a maximal incremental running test while in the second session, they were instructed to run during one minute under different loading (0%, +10% and +20% of body mass [BM]) and velocity (60%, 80% and 100% of MAS) conditions in a random order. Spatiotemporal data were recorded and then running mechanics modelled using the spring-mass model. The main results indicated that vertical and leg stiffness (Kvert and Kleg, respectively) were increased (P?P?>?.05) when load was changed. At the same time, alterations of the running kinematics were observed such as longer contact times, reduced flight times, stride frequencies and step lengths, as well as an increase of the centre of mass dynamics. Based on these results it is assumed that runners maintain a certain stiffness level for each velocity despite different loading conditions. As a consequence, Fpeak increases and this probably causes spatiotemporal adjustments in the movement kinematics.  相似文献   

Quality flaw prediction in Spanish Wikipedia: A case of study with verifiability flaws     

Edgardo Ferretti  Leticia Cagnina  Viviana Paiz  Sebastián Delle Donne  Rodrigo Zacagnini  Marcelo Errecalde 《Information processing & management》2018,54(6):1169-1181

In this work, we present the first quality flaw prediction study for articles containing the two most frequent verifiability flaws in Spanish Wikipedia: articles which do not cite any references or sources at all (denominated Unreferenced) and articles that need additional citations for verification (so-called Refimprove). Based on the underlying characteristics of each flaw, different state-of-the-art approaches were evaluated. For articles not citing any references, a well-established rule-based approach was evaluated and interesting findings show that some of them suffer from Refimprove flaw instead. Likewise, for articles that need additional citations for verification, the well-known PU learning and one-class classification approaches were evaluated. Besides, new methods were compared and a new feature was also proposed to model this latter flaw. The results showed that new methods such as under-bagged decision trees with sum or majority voting rules, biased-SVM, and centroid-based balanced SVM, perform best in comparison with the ones previously published.  相似文献   

湖南省大学生有氧耐力评价标准研究   总被引：4，自引：0，他引：4  

邬似刚  熊曼丽  孙洪涛  王铁生 《中国体育科技》2003,39(3):54-55

对湖南省文、理、工、医、农 5类专业 6 0 0名二年级与四年级男、女大学生进行 12min跑测验 ,并用RPE值对运动负荷进行监控。结果显示 ,用 12min跑间接测定大学生的最大耗氧量是可行的 ,据此制定了湖南省大学生有氧耐力评价标准。  相似文献   

Introduction: Scientific and Technological Textbooks in the European Periphery     

José Ramón Bertomeu-sánchez  Antonio García-Belmar  Anders Lundgren  Manolis Patiniotis 《Science & Education》2006,15(7-8):657-665

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The View from Above: Map Reading Skills Project     

Derek Potgieter  Sandra Olën 《International Information and Library Review》1993,25(4)

In South Africa the education system for black children is fraught with problems. These problems are the direct result of apartheid and have been compounded by poverty and illiteracy. In this article the problem of poorly qualified or unqualified teachers is discussed especially with regard to the teaching of map skills to children in their fifth school year. The project team needed to develop affordable materials which could be used in large classes by teachers after a very short period of training. Books and other materials which are available commercially were examined, but for various reasons were found to be unsuitable for local conditions. After determining the extent of the problem, the project team followed a grassroots process of developing a flip chart which teachers learnt to use with confidence and which enabled pupils to master the concepts and skills necessary for understanding a map.  相似文献   

短跑教学中如何发挥教师的主导性和学生的主体性     

杨学军  李兴锱  司虎克  黄顺章  王兴 《上海体育学院学报》1993,(4)

采用调查与实验对比的方法,论述了短跑教学中有利于发挥教师的主导性和学生的主体性的几个操作步骤。  相似文献   

图书馆的学术地位刍议-兼与程焕文馆长商榷   总被引：3，自引：0，他引：3  

司步林 《大学图书馆学报》2002,20(3):76-78

在论述图书馆学术性的基础上,通过对图书馆学术定位的理解、图书馆学指导下的图书馆工作及“学术”释义,探讨了图书馆的学术地位.  相似文献   

THE INCREDIBLE EXPANDING UNIVERSE     

n.clars 《科学中国》2003,(12):80

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我国体育科学研究领域亟需学术批判   总被引：2，自引：0，他引：2  

刘四 《浙江体育科学》2005,27(4):94-96,F003

对近几年国内主要十二种体育期刊刊载的学术论文进行统计、分析,批判性论文仅占刊载论文的0.51%.只有积极开展学术批评,才能使体育科学研究百花齐放、百家争鸣,推动体育科学研究健康发展.要开展学术批判,就要正确对待书本知识,辨证的看待"专家"、"名人",有批判地学习外国先进经验,要注意逻辑证明的作用.同时,在体育科学领域开展学术批判还要注意学术批判都是建设性的,应具有实事求是的精神和宽广的胸怀.  相似文献   

田径运动与教学艺术     

李思 《天津体育学院学报》1995,10(2):58-59

田径运动与教学艺术李思ＴＲＡＣＫＡＮＤＦＩＥＬＤＡＮＤＩＴＳＴＥＡＣＨＩＮＧＳＫＩＬＬ￥ＬｉＳｉ１中跑项目与教学艺术中跑运动是耐力性项目，对锻炼心血管系统，改善心肺功能有较积极意义。但是中跑运动单调枯燥，学生既害伯，又担心考试不及格。针对学生这种心理...  相似文献