Net efficiency of roller skiing with a diagonal stride   总被引：1，自引：0，他引：1  

Nakai A  Ito A 《Journal of sports sciences》2011,29(4):423-429

The aims of this study were: (a) to determine net efficiency during roller skiing with a diagonal stride at various speeds; (b) to assess the development of net efficiency across speeds; and (c) to examine the characteristics of efficiency in diagonal roller skiing. Two-dimensional kinematics and oxygen uptake were determined in eight male collegiate cross-country ski athletes who roller skied with the diagonal stride at various speeds on a level track. Net efficiency was calculated from rates of internal and external work and net energy expenditure. Individual net efficiency ranged from 17.7% to 52.1%. Net efficiency in the entire group of athletes increased with increasing speed, reached a maximum value of 37.3% at 3.68?m?·?s(-1), before slowly decreasing. These findings indicate that roller skiing with the diagonal stride at high speed is a highly efficient movement and that an optimal speed exists at which net efficiency can be maximally enhanced in diagonal roller skiing.  相似文献   

Contributions of processes using semantic information and character-to-sound correspondences to kanji word-reading performance in Japanese primary school children     

Ami Sambai  Mayu Tsukada  Ayaka Miki  Akira Uno 《Journal of Research in Reading》2023,46(2):163-186

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Declining symptom of academic productivity in the Japanese research university sector     

Akira Arimoto 《Higher Education》2015,70(2):155-172

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A three-dimensional analysis of the contributions of upper limb joint movements to horizontal racket head velocity at ball impact during tennis serving     

Satoru Tanabe  Akira Ito 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):418-433

In this study, we examined the relationship between upper limb joint movements and horizontal racket head velocity to clarify joint movements for developing racket head speed during tennis serving. Sixty-six male tennis players were videotaped at 200 Hz using two high-speed video cameras while hitting high-speed serves. The contributions of each joint rotation to horizontal racket velocity were calculated using vector cross-products between the angular velocity vectors of each joint movement and relative position vectors from each joint to the racket head. Major contributors to horizontal racket head velocity at ball impact were shoulder internal rotation (41.1%) and wrist palmar flexion (31.7%). The contribution of internal rotation showed a significant positive correlation with horizontal racket head velocity at impact (r = 0.490, P < 0.001), while the contribution of palmar flexion showed a significant negative correlation (r = ? 0.431, P < 0.001). The joint movement producing the difference in horizontal racket head velocity between fast and slow servers was shoulder internal rotation, and angular velocity of shoulder internal rotation must be developed to produce a high racket speed.  相似文献   

Politics,state and Church: forming the National Society 1805–c.1818     

Akira Iwashita 《History of education》2018,47(1):1-17

This article explores the process of the formation of ‘the National Society for Promoting the Education of the Poor in the Principles of the Established Church’ through focusing on disagreements amongst its promoters. It demonstrates that a discrepancy existed in the opinions of Anglican promoters concerning what an Anglican national institution should be like, and that the formation of the National Society was a process of compromise between these promoters. The formation and the first phase of operation of the society show that the National Society can be regarded as a more liberal and comprehensive organisation than earlier literature has suggested. The study also shows that the formation and early operation of the National Society can be seen as a forgotten origin of the liberal education policy founded in the 1830s.  相似文献   

Relationship between reading/writing skills and cognitive abilities among Japanese primary-school children: normal readers versus poor readers (dyslexics)     

Akira Uno  Taeko N. Wydell  Noriko Haruhara  Masato Kaneko  Naoko Shinya 《Reading and writing》2009,22(7):755-789

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Kinetics of throwing arm joints and the trunk motion during an overarm distance throw by skilled Japanese elementary school boys     

Yasuto Kobayashi  Michiyoshi Ae  Akiyo Miyazaki  Norihisa Fujii  Akira Iiboshi  Hideki Nakatani 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):314-328

The purpose of this study was to investigate joint kinetics of the throwing arms and role of trunk motion in skilled elementary school boys during an overarm distance throw. Throwing motions of 42 boys from second, fourth, and sixth grade were videotaped with three high-speed cameras operating at 300 fps. Seven skilled boys from each grade were selected on the basis of throwing distance for three-dimensional kinetic analysis. Joint forces, torques, and torque powers of the throwing arm joints were calculated from reconstructed three-dimensional coordinate data smoothed at cut-off frequencies of 10.5–15 Hz and by the inverse dynamics method. Throwing distance and ball velocity significantly increased with school grade. The angular velocity of elbow extension before ball release increased with school grade, although no significant increase between the grades was observed in peak extension torque of elbow joint. The joint torque power of shoulder internal/external rotation tended to increase with school grade. When teaching the overarm throw, elementary school teachers should observe large backward twisting of trunk during the striding phase and should keep in mind that young children, such as second graders (age 8 years), will be unable to effectively utilise shoulder external/internal rotation during the throwing phase.  相似文献   

Teacher Internship and the Culture of Teaching in Japan     

Nobuo K. Shimahara  Akira Sakai 《British Journal of Sociology of Education》1992,13(2):147-162

Japan's teacher internship was a hotly debated political issue for three decades until the legislature finally approved its implementation in 1988. The aim of this paper is to explore how the culture of teaching mediated the implementation of the government‐sponsored teacher internship. The data presented in this paper come from ethnographic research conducted in 1989 with a focus on three elementary public schools in Tokyo. Our findings suggest that the culture of teaching measurably influenced the administration of internship in the first year. As a result, internship became ineffective if measured by the Government's expectations. This paper argues that the Government's reform, of teaching is bound to be ineffectual without classroom teachers’ active support for it.  相似文献   

Conflict resolution styles among COLLECTIVIST cultures: a comparison between Japanese and Koreans     

Akira Miyahara  Min-Sun Kim  Ho-Chang Shin  Kak Yoon 《Int J Intercult Relat》1998,22(4):60

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短跑道速滑起跑动作及肌电图分析     

俞劲楠  伊藤章  吉井健悟 《山西师大体育学院学报》2010,25(1):119-121

运用三台高速摄影机对三名优秀女子短道速度滑冰运动员起跑动作进行解析分析。研究表明：在起跑过程中股关节始终保持着外转位,在整个身体倾斜的状态下发挥着蹬冰力,臀中肌在这样的动作中起到了决定性的作用。在肌电图的解析中,利用足关节的屈曲动作既完成了移动身体重心又保持了身体前倾,在这样的状态下进行蹬冰的过程中,胫骨前肌起到了极其重要的作用。因此,对臀中肌及胫骨前肌,应采取积极的训练。  相似文献