排序方式： 共有25条查询结果，搜索用时 312 毫秒
1.
2.
Takei Y Dunn JH Blucker E 《Sports biomechanics / International Society of Biomechanics in Sports》2003,2(2):141-162
The 16 highest-scored Roche vaults (G1) performed during the 2000 Olympic Games were compared with those receiving the 16 lowest-scores (G2). A 16-mm motion picture camera operating at 100 Hz recorded the vaults during the competition. The results of t tests (p < .05) indicated G1, compared to G2, had (a) shorter time of board support, greater normalised average upward vertical force and backward horizontal force exerted by the board, greater change in the vertical velocity while on the board, and greater vertical velocity at board take-off, (b) comparable linear and angular motions in pre-flight, (c) smaller backward horizontal impulse exerted by the horse, smaller loss of the horizontal velocity while on the horse, and greater horizontal and vertical velocities at horse take-off, (d) greater height and larger horizontal distance of post-flight, (e) higher body mass centre at knee release, and (f) higher mass centre, greater normalised moment of inertia, and smaller vertical velocity at mat touchdown. Therefore, gymnasts and coaches should focus on sprinting the approach; blocking and pushing-off the take-off board rapidly and vigorously; departing the board with a large vertical velocity; exerting large downward vertical force and small forward horizontal force from the hand-stand position while on the horse; departing the horse with large horizontal and vertical velocities; and completing the majority of the double salto forward near the peak of trajectory and releasing the knees above the top of the horse to prepare for a controlled landing. 相似文献
3.
The aim of this study was to compare the somersaulting techniques used in the 16 highest-scoring and 16 lowest-scoring Roche vaults. Our hypothesis was that the gymnasts performing the highest-scoring Roche vaults would demonstrate a better technique than those performing the lowest-scoring Roche vaults while on the horse (pushing off the horse more effectively), somersaulting (executing most of the required somersaults higher in flight), and landing (showing a greater control). A 16-mm motion picture camera, operating at 100 Hz, recorded the vaults during the official competition. The two-dimensional direct linear transformation was used for spatial reconstruction. The results of t-tests (P < 0.05) indicated that, compared with the low-scoring gymnasts, the high-scoring gymnasts had: (1) greater height of body centre of mass and a more fully extended body position at the horse take-off; (2) greater height of body centre of mass at the peak of post-flight, knee release, and touchdown on the mat; (3) greater horizontal and vertical displacements of body centre of mass, greater somersaulting rotation, and longer time from the knee release to mat touchdown; and (d) markedly smaller landing point deductions. In conclusion, a successful Roche vault is likely when the focus is on: (a) leaving the horse with a large vertical velocity in an extended body position to achieve a high trajectory of centre of mass by first extending the legs, then immediately pushing off the horse vigorously, using the muscles of the upper extremity; (b) grasping the knees immediately after the take-off from the horse, achieving the tightly tucked body position early during the ascent to the peak, and completing two-thirds of the required somersaults at a great height; (c) releasing the knees and extending the body above the top level of the horse; and (d) contacting the mat with a high body centre of mass position. 相似文献
4.
The role of attention in perceptual learning has been a topic of controversy. Sensory psychophysicists/physiologists and animal
learning psychologists have conducted numerous studies to examine this role; but because these two types of researchers use
two very different lines of approach, their findings have never been effectively integrated. In the present article, we review
studies from both lines and use exposure-based learning experiments to discuss the role of attention in perceptual learning.
In addition, we propose a model in which exposure-based learning occurs only when a task-irrelevant feature is weak. We hope
that this article will provide new insight into the role of attention in perceptual learning to the benefit of both sensory
psychophysicists/physiologists and animal learning psychologists. 相似文献
5.
Elizabeth Mack Helen Augare Linda Different Cloud-Jones Dominique Davíd Helene Quiver Gaddie Rose E. Honey Angayuqaq O. Kawagley Melissa Little Plume-Weatherwax Lisa Lone Fight Gene Meier Tachini Pete James Rattling Leaf Elvin Returns From Scout Bonnie Sachatello-Sawyer Hi’ilani Shibata Shelly Valdez Rachel Wippert 《Cultural Studies of Science Education》2012,7(1):49-70
There are a growing number of informal science education (ISE) programs in Native communities that engage youth in science education and that are grounded in Native ways of knowing. There is also a growing body of research focusing on the relationship between culture, traditional knowledge, and science education. However, there is little research documenting how these programs are being developed and the ways in which culture and Western science are incorporated into the activities. This study outlines effective practices for using Native ways of knowing to strengthen ISE programs. These effective practices may also be used to promote change in formal education. The authors combine an overview of current research in informal science education with personal interviews with educators engaged in ISE programs offered to youth both on and off tribal reservations as well as experts in Indigenous education. Participating individuals and programs included Native communities across the United States, including Alaska and Hawai??i. Keeping in mind that each community is unique, ISE programs that are grounded in Native ways of knowing will benefit by utilizing the effective practices outlined here as a guide for starting or strengthening existing ISE programs relevant to the needs of their communities. 相似文献
6.
7.
Masako Shibata 《History of education》2013,42(1):75-85
This study focuses on the Soviet introduction of local studies to Ukrainian schools during the 1920s. It argues that, through their efforts at pedagogical reform, educational planners sought a fundamental re‐imagining of place. The Ukrainian Commissariat of Education asked teachers and their students to engage the ‘productive’ world surrounding the school and make connections to an understanding of a nationally defined, territorial Ukraine. However, because the commissariat left decisions regarding curricular content to regions and municipalities, many instructors were able to resist this utilitarian notion of space. Local studies was the linchpin in Soviet educational reform for Ukraine, yet the state’s emphasis on decentralised planning created opportunity for ‘flawed’ interpretations of local and, consequently, national meanings. 相似文献
8.
9.
10.
Yoshiaki Takei J. Hubert Dunn Erik Blucker 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):141-162
The 16 highest‐scored Roche vaults (G1) performed during the 2000 Olympic Games were compared with those receiving the 16 lowest‐scores (G2). A 16‐mm motion picture camera operating at 100 Hz recorded the vaults during the competition. The results of t tests (p < .05) indicated G1, compared to G2, had (a) shorter time of board support, greater normalised average upward vertical force and backward horizontal force exerted by the board, greater change in the vertical velocity while on the board, and greater vertical velocity at board take‐off, (b) comparable linear and angular motions in pre‐flight, (c) smaller backward horizontal impulse exerted by the horse, smaller loss of the horizontal velocity while on the horse, and greater horizontal and vertical velocities at horse take‐off, (d) greater height and larger horizontal distance of post‐flight, (e) higher body mass centre at knee release, and (f) higher mass centre, greater normalised moment of inertia, and smaller vertical velocity at mat touchdown. Therefore, gymnasts and coaches should focus on sprinting the approach; blocking and pushing‐off the take‐off board rapidly and vigorously; departing the board with a large vertical velocity; exerting large downward vertical force and small forward horizontal force from the handstand position while on the horse; departing the horse with large horizontal and vertical velocities; and completing the majority of the double salto forward near the peak of trajectory and releasing the knees above the top of the horse to prepare for a controlled landing. 相似文献