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1.
Koyama H Muraki Y Ae M 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):139-153
We investigated the immediate effects of the combined use of inclined and raised flat boards on the take-off motion of the long jump. Eight male long jumpers were videotaped with two high-speed video cameras (250 Hz) set perpendicular to the runway. The athletes jumped with three modified take-off boards: upward-inclined boards of two different inclinations (2.5 and 5.0 degrees), and a raised flat board (50 mm high). The jumpers performed pre- and post-jumps using their own techniques before and after use of the boards to test their effects. The post- jump revealed significantly less reduction in the horizontal velocity during the take-off than the pre-jump, and the effectiveness of converting the velocity from horizontal to vertical increased significantly in the post-jump. The post-jump demonstrated significantly less knee flexion of the take-off leg during take-off. The reduced knee flexion and slower extension velocity of the take-off leg in the second phase of the post-jump contributed to increasing the knee extension torque in the second phase and resulted in the increases in vertical ground reaction force and vertical velocity. These results suggest that the combined use of the inclined and raised flat boards induced immediate effective changes in the kinematics and kinetics of the take-off motion and represent appropriate training tools for take-off techniques of the long jump. 相似文献
2.
Thirty‐six children with cerebral palsy, aged 3.5 to 4.5 years were compared on their skills for independence. Of the 36 boys and girls, 19 children were enrolled in a Conductive Education Program in Birmingham and 17 were enrolled in British special education programs in the Greater Manchester area. Skills for independence were measured with the Vineland Adaptive Behavior Scales via teachers’ responses, once a year on three occasions. Parents were interviewed using the Developmental Profile 2, once a year on three occasions. The results of two‐way ANOVA with one repeated measure on both teachers’ and parents’ responses indicate that there was no significant difference between the two groups in their skills for independence. However, both groups performed significantly better as they were getting older. Despite the strong emphasis on independence in Conductive Education, the children's level of independence was no different from their counterparts. Thus, the claim for the effectiveness of Conductive Education is not supported by the study. 相似文献
3.
Yuta Suzuki Michiyoshi Ae Shunsuke Takenaka Norihisa Fujii 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(2):144-153
The purpose of this study was to investigate differences in the support leg joint moment and moment power between side-step (SS) and cross-step (CS) cutting techniques with a prescribed 90° cutting angle. Ground reaction forces (1,000 Hz) and three-dimensional kinematics (250 Hz) of SS and CS cutting techniques were collected from 20 male college athletes. Normalised peak knee extension moment was larger in the SS technique than in the CS technique (0.40 ± 0.10 in SS; 0.26 ± 0.08 in CS). In the SS technique, the knee extensors ( ? 0.10 ± 0.06 in SS; ? 0.02 ± 0.04 in CS) and ankle plantarflexors ( ? 0.12 ± 0.05 in SS; ? 0.07 ± 0.03 in CS) did significantly more negative work (normalised). The direction change angle (40.5 ± 8.7° in SS; 33.0 ± 6.8° in CS) and the decrease in horizontal velocity of the centre of mass ( ? 0.63 ± 0.23 m/s in SS; ? 0.31 ± 0.23 m/s in CS) were significantly larger in the SS technique. These results suggest that the SS technique is an effective means of changing running direction at the expense of velocity of the centre of mass and that the CS technique is better for minimising the reduction in horizontal velocity of the centre of mass. 相似文献
4.
Takanori Ishii Michiyoshi Ae Yuta Suzuki Yasuto Kobayashi 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(2):238-250
This study sought to identify biomechanical factors that determine fast and skilful execution of the seoi-nage (shoulder throw) technique by comparing kinematics between elite and college judo athletes. Three-dimensional motion data were captured using a VICON-MX system with 18 cameras operating at 250 Hz as three male elite and seven male college judo athletes performed seoi-nage. No significant difference was found in motion phase time of the turning phase between the two groups, indicating that motion phase time is not necessarily a factor contributing quickness in seoi-nage. The maximum relative velocity of the whole body centre of mass along the anterior–posterior direction was significantly greater in the elite athletes (2.74 ± 0.33 m/s) than in the college athletes (1.62 ± 0.47 m/s) during the turning phase (p = 0.023). The overall angular velocity of the body part lines, particularly the arm line, tended to be greater in the elite athletes (p = 0.068). The results imply that the velocity of the thrower relative to the opponent in the forward drive and turning motion reflects high skill seoi-nage. Coaches should recognise the relative forward velocity as a factor that may contribute to a successful seoi-nage when teaching the judo throw technique. 相似文献
5.
Koyama H Muraki Y Ae M 《Sports biomechanics / International Society of Biomechanics in Sports》2005,4(2):113-129
In this study, we investigated the effects of inclined and raised flat boards on the take-off motion of the long jump to determine the effectiveness of these boards as training tools. Eight male long jumpers were videotaped with two high-speed video cameras (250 Hz) set perpendicular to the runway. Four different jumps were performed with in four conditions, all with their medium length run-up: a long jump with their normal technique, long jumps on upward inclined boards of two different inclinations (2.5 and 5.0 degrees), and a long jump on a raised flat board (0 degrees, 50 mm). The raised flat board enhanced the pivot of the body over the take-off foot, and reduced flexion of the take-off leg knee. However, the inclined boards did not produce the same effects as the raised flat board. The use of the inclined boards increased the vertical velocity of the centre of mass of the body at toe-off, resulting in increased airborne time. These results suggest that the raised flat board and inclined boards would be effective in improving long jumpers' techniques during the take-off and airborne phases. 相似文献
6.
Jeong‐Ae Park 《The International Journal of Art & Design Education》2009,28(2):183-193
This article examines some characteristics of art education in Korea. It takes the form of a historical overview using a postcolonial lens. The findings were that the predominant Western aesthetic concepts and theories as central culture embodied in Korean art education as local culture are: (i) ideas of art as self‐expression developed in Europe and the USA between the 1920s and 1950s; (ii) the concept of art in daily living in the USA in the 1930s; (iii) design elements and principles by Arthur Wesley Dow in the USA in the 1920s; (iv) Bauhaus design theory in Europe in the 1920s; and (v) the appreciation of nature beauty by John Ruskin in the late nineteenth century in England. These educational ideas have been influential on policy‐making in Korean art education, and therefore new concepts are integrated with these elements for curriculum changes. In this way, the characteristic of the colonised Korean art curriculum is so hybrid that it is difficult to understand the concepts and the practical implications of the various policies for art teaching. Consequently, it has not served the issues of cultural diversity and pluralism that are so problematic in twenty‐first century Korean society. 相似文献
7.
Jeong‐Ae Park 《The International Journal of Art & Design Education》2014,33(2):223-234
This article reports research on New York‐based Korean artists' dynamic processes of identity‐shaping and the implications that these processes have for art education. The study uses postcolonial theories that illuminate the dialectical process of hybrid cultural production in the global dimension. The artists' identities narrated elucidate the recognition of difference with others; this identification emerges as the artists simultaneously escape from and discover their Korean identities. The artists' childhood experiences and memories work as reflective thinking in their different context, and because of their search for an individual identity, Korean culture is an important factor in their art making. When their identity formation and practice are in constant negotiation with difference, this results in learning and translating from others. They assume an ‘open universalism’ necessary to communicate at an international level, and as a consequence these artists' identity formation always involves the process of a doubling and dividing of reflections of existing Korean identities as well as the building of new ones. In this dualistic state, the artists' multiple identities remain heterogeneous, composed of contradictory factors that are revealed in the artists' hybrid artworks. 相似文献
8.
Davison and Ramesh expressed equivalently the condition for the characteristic roots of a real matrix to lie within a sector by the condition for a matrixof doubled order to be Hurwitzian (1). A further generalization of their result is given in this note. 相似文献
9.
Takehiro Mori Michiyoshi Kuwahara Norio Fukuma 《Journal of The Franklin Institute》1982,314(2):123-127
It is well known that the Lyapunov matrix equation can be utilized to obtain the estimate for the transient behavior of linear constant systems. This paper shows that the equation gives information not only on the maximum real part of the characteristic roots of system matrix but also on other extremal values to these roots. 相似文献
10.
Kazumichi Ae Sekiya Koike Takashi Kawamura 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(4):452-466
ABSTRACT The aim of this study was to investigate the kinetic functions of the lower limbs at different hitting-point heights to provide key information for improving batting technique in baseball players. Three-dimensional coordinate data were acquired using a motion capture system (250 Hz) and ground reaction forces were measured using three force platforms (1000 Hz) in 22 male collegiate baseball players during tee-batting set at three different hitting-point heights (high, middle, and low). Kinetic data were used to calculate joint torque and mechanical work in the lower limbs by the inverse dynamics approach. The peak angular velocity of the lower trunk about the vertical axis was smaller under the low condition. The joint torques and mechanical works done by both hip adduction/abduction axes were different among the three conditions. These results indicate that hip adduction/abduction torques mainly contribute to a change in the rotational movement of the lower body about the vertical axis when adjusting for different hitting-point heights. In order to adjust for the low hitting-point height which would be difficult compared with other hitting-point heights, batters should focus on rotating the lower trunk slowly by increasing both hip abduction torques. 相似文献