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1.
A non-rotational (NR) shot is now a well-known scoring move in soccer. To execute the NR shot, it is necessary to deprive the ball of any rotational forces during the impact phase. To execute the NR shot, it is natural that the force vector acting from the foot would pass through the ball’s center of gravity; however, the coordinated motion of the lower limb joint’s angular displacement and the pelvis is still unclear. The aim of this study is to estimate the coordinated leg and pelvis motion during the NR shot as compared to that during instep kicking. Four right-leg dominant college league players were asked to perform a NR shot and an instep kick a total of 10 times each. Hip, knee, and ankle joint angular displacements in the sagittal plane and pelvis yaw and roll rotational motions during both types of kicks were calculated with 14 IR reflective markers using a 3D real-time motion analysis system with a 250-Hz sampling. The Euclidean distances of the joint space of the NR shot and the instep kick were also calculated to detect similarities in the coordinated motion of the lower limb. The results showed that the lower limb joint motions in the sagittal plane were not different; however, the pelvis roll and yaw motions were apparently different, and these phenomena could simulate a pendulum motion with changes in both the vertical and horizontal displacements. These results suggest that the coordinated motion of the lower limb joint’s angular displacement shows high similarity between the NR shot and the instep kick, and the pelvis roll and yaw synchronized orientation is essential for achieving the NR shot. 相似文献
2.
At the University of Electro‐Communications instruction is given on fundamental electricity in accordance with the educational principles derived from the philosophy of ‘Zen’. On the technical side, CCTV interphones and other audio‐visual aids are employed. In particular, we have inaugurated a remote instruction method called ‘TV‐Interphone’, abbreviated to T.I. method, through which we give personal guidance to students in the conduct of their experiments. Data from the experiments are fed into a computer which was installed in the laboratory for control processing
Three courses are provided:
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1. Electrical Measurements and Characteristics of Analogue and Digital Circuits.
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2. Electrical Measurements and Characteristics of Advanced Analogue Circuits
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3. Design and Experiment
3.
Tsuyoshi Takeda Osamu Itoi Hideki Takagi Shozo Tsubakimoto 《Journal of sports sciences》2013,31(7):635-641
AbstractThe purpose of this study was to clarify factors to perform the hole-entry technique in the backstroke start. A total of 16 well-trained Japanese competitive swimmers were divided into two groups (backstroke specialists and non-specialists) to compare their backstroke start motions. Their backstroke motions were videotaped, and two-dimensional co-ordinates for the swimmers were obtained from the video images using direct linear transformation methods. A non-paired t-test and Mann–Whitney U-test were used to analyse the statistical difference of the kinematic variables between the groups. Backstroke specialists showed a significantly shorter 5 m time (P = 0.009, effect size = –1.54), a significantly higher position of the toe (P = 0.010, effect size = 1.47) at signal and of the hip at toe-off (P = 0.002, effect size = 1.94), a significantly larger hip joint angle at toe-off (P = 0.007, effect size = 1.60) and a significantly higher angular velocities of the hip joints (45–85%; P < 0.05) for the normalised time as compared to that of non-specialists. An earlier initiation of the extension and the maintenance of a higher extension speed at the hip joints were important factors in achieving an arched-back posture, which facilitated and water entrance with a small entry range. 相似文献
4.
Hideki Takagi Motomu Nakashima Yohei Sato Kazuo Matsuuchi 《Journal of sports sciences》2016,34(16):1564-1580
This paper reviews unsteady flow conditions in human swimming and identifies the limitations and future potential of the current methods of analysing unsteady flow. The capability of computational fluid dynamics (CFD) has been extended from approaches assuming steady-state conditions to consideration of unsteady/transient conditions associated with the body motion of a swimmer. However, to predict hydrodynamic forces and the swimmer’s potential speeds accurately, more robust and efficient numerical methods are necessary, coupled with validation procedures, requiring detailed experimental data reflecting local flow. Experimental data obtained by particle image velocimetry (PIV) in this area are limited, because at present observations are restricted to a two-dimensional 1.0 m2 area, though this could be improved if the output range of the associated laser sheet increased. Simulations of human swimming are expected to improve competitive swimming, and our review has identified two important advances relating to understanding the flow conditions affecting performance in front crawl swimming: one is a mechanism for generating unsteady fluid forces, and the other is a theory relating to increased speed and efficiency. 相似文献
5.
Tokio Takagi Toshiharu Yokozawa Yuki Inaba Yuji Matsuda Hitoshi Shiraki 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(3):387-398
Since clubface orientation at impact affects ball direction and ball spin, the ability to control clubface orientation is one of the most important skills for golfers. This study presents a new method to describe clubface orientation as a function of the clubshaft motions (i.e., swing plane orientation, clubshaft angle in the swing plane, and clubshaft rolling angle) during a golf swing and investigates the relationships between the clubshaft motions and clubface orientation at impact. The club motion data of driver shots were collected from eight skilled golfers using a three-dimensional motion capture system. The degrees of influence of the clubshaft motions on the clubface orientation were investigated using sensitivity analysis. The sensitivity analysis revealed that the swing plane horizontal angle affected the clubface horizontal angle to an extent of 100%, that the clubshaft angle in the swing plane affected both the clubface vertical and horizontal angles to extents of 74 and 68%, respectively, and that the clubshaft rolling angle affected both the clubface vertical and horizontal angles to extents of -67 and 75%, respectively. Since the method presented here relates clubface orientation to clubshaft motions, it is useful for understanding the clubface control of a golfer. 相似文献
6.
本文通过分析敦煌遗书中作为语言方面的材料,如古逸文献,对音资料以及敦煌学中重要的河西语言圈中的语言史材料,梳理了学界由敦煌文献为汉语史研究带来的新见解,指出今后的研究重点及发展路子. 相似文献
7.
Tsuyoshi Takeda Shin Sakai Hideki Takagi Keisuke Okuno Shozo Tsubakimoto 《Journal of sports sciences》2017,35(6):565-571
This study examines the hand and foot reaction force recorded independently while performing the kick-start technique. Eleven male competitive swimmers performed three trials for the kick-start with maximum effort. Three force platforms (main block, backplate and handgrip) were used to measure reaction forces during starting motion. Force impulses from the hands, front foot and rearfoot were calculated via time integration. During the kick-start, the vertical impulse from the front foot was significantly higher than that from the rearfoot and the horizontal impulse from the rearfoot was significantly higher than that from the front foot. The force impulse from the front foot was dominant for generating vertical take-off velocity and the force impulse from the rearfoot was dominant for horizontal take-off velocity. The kick-start’s shorter block time in comparison to prior measurements of the grab start was explained by the development of horizontal reaction force from the hands and the rearfoot at the beginning of the starting motion. 相似文献
8.
TAKAGI Tasuku 《浙江大学学报(A卷英文版)》2007,8(3):357-360
Electric contact discharge is subject closely related to digital information transmission, and integrity of digital signals for realizing high reliablility transmission. This kind of problem is a part of EMC (electromagnetic compatibility). From such a viewpoint, contact noise problems will be mentioned which disturb and degrade digital signals. The induction noise and radiation noise from discharge, electrostatic discharge (ESD), and connector related fundamental subject will be mentioned. 相似文献
9.
Sven P. Hoekstra Yoshi-Ichiro Kamijo Tokio Kinoshita Ben T. Stephenson Victoria L. Goosey-Tolfrey 《Journal of sports sciences》2019,37(15):1717-1724
This study investigates the relationship between autonomic function and the inflammatory response to a wheelchair half-marathon in people with a spinal cord injury (SCI). Seventeen wheelchair athletes with a cervical SCI (CSCI, N = 7) and without CSCI (NON-CSCI, N = 10) participated in a wheelchair half-marathon. Blood was taken prior, post and 1 h post-race to determine the concentrations of adrenaline, noradrenaline, extracellular heat shock protein 72 (eHsp72) and interleukin-6 (IL-6). A sit-up tilt test was performed to assess autonomic function at rest. CSCI showed a lower supine ratio of the low and high frequency power of the variability in RR intervals (LF/HF RRI, p = 0.038), total and low frequency power of the systolic blood pressure variability (TP SBP, p < 0.001; LF SBP, p = 0.005) compared to NON-CSCI. Following the race, catecholamine concentrations increased only in NON-CSCI (p < 0.036). The increase in IL-6 post-race was larger in NON-CSCI (p = 0.040). Post-race catecholamine levels explained 60% of the variance in the IL-6 response (r = 0.77, p = 0.040), which was further increased when the resting autonomic function indices were added to the regression model (R2 > 81%, p < 0.012). In summary, the dampened acute inflammatory response to a wheelchair half-marathon in CSCI was strongly associated with the autonomic dysfunction present in this group. 相似文献
10.
Kohei Takagi 《Journal of Higher Education Policy & Management》2018,40(3):272-286
In the shifting environment of higher education, characterised by financial constraints, institutional competition and governmental steering, universities adopt a new stream of missions. In Japan, internationalisation and the acquisition of a global outlook have become a key strategy. The trend is endorsed through competitive public funding schemes, based on the belief that competition fosters so-called world-class universities. These schemes necessitate not only internationalisation of curriculum and research but also a wide range of projects and programs, which require talents that may not be readily found in the existing cadres of university workers. This empirical research assesses experiences and perceptions of project-based professionals in Japanese universities. It found unique ways in which ‘Specially appointed academic staff’ are given project and administrative responsibilities but with limited access to environment and/or support system for research. Discussions focus on impacts of such appointment on their academic career and explore how these institutional projects may be handled in regards to university organisation. 相似文献