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Toshiyuki Fujihara Takafumi Fuchimoto Pierre Gervais 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(1):22-38
The aim of this study was to analyse the principal mechanics of circles. Seventeen university male gymnasts performed circles on an instrumented pommel horse model that enabled the pommel reaction forces to be recorded at 1000 Hz with two force plates. The circles were also videotaped using two digital video cameras operating at 60 frames per second. During circles, the vertical component of the reaction forces peaked in the double-hand support phases. Changes in the velocity of the centre of mass corresponded to the change in the tangential components of horizontal reaction forces. The velocity of the centre of mass had its peaks in the single-hand support phases and its local minimums in the double-hand support phases. The velocity of the ankles and that of the centre of mass of the head and trunk were minimal in the single-hand support phases and were maximal in the double-hand support phases. These results suggest that the circles were composed of vertical movements and two kinds of rotations: rotation of the centre of mass and rotation of the body itself about the centre of mass. These two kinds of rotations, which influence the legs' rotational velocity, are phase dependent. To further our understanding of circles, research on circles in different orientations on the pommel horse will be beneficial. 相似文献
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在中国,将基于XML元数据互操作技术实际应用到国际化规模性科技信息系统之间的案例并不多见。在遵循国际元数据有关标准的前提下,需要分析合作双方各家元数据的体系结构,再从概念层面对每一元素进行互映射,开发基于XML元数据交换的互操作系统。这些都是必不可少的处理环节。我们以日本科学技术振兴机构运维的亚洲科技门户电子期计检索网站为平台,在中国科学技术信息研究所承担的科技部科技精品期刊项目研究成果的基础上,启动并实施了基于XML元数据交换任务的国际化科技系统问的互操作工作,本文就上述研发内容进行介绍。 相似文献
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Kawano H Iemitsu M Gando Y Ishijima T Asaka M Aoyama T Ando T Tokizawa K Miyachi M Sakamoto S Higuchi M 《Journal of sports sciences》2012,30(3):241-246
The present study elucidated the effects of habitual rowing exercise on arterial stiffness and plasma levels of the vasoconstrictor endothelin-1 and the vasodilator nitric oxide (NO) in older men. Eleven rowers (68.0 ± 1.6 years) and 11 sedentary control older men (64.9 ± 1.1 years) were studied. Peak oxygen uptake (36.0 ± 1.7 vs. 27.7 ±1.9 ml · kg(-1) · min(-1)), leg press power (1346 ± 99 vs. 1077 ± 68 W), and HDL-cholesterol (75 ± 5 vs. 58 ±3 mg · ml(-1)) were higher and triglyceride (78 ± 9 vs. 120 ± 14 mg · ml(-1)) was lower in rowers than in control participants (all P < 0.05). Arterial stiffness indices (carotid β-stiffness and cardio-ankle vascular index) and plasma endothelin-1 and NOx (nitrite + nitrate) levels did not differ between the two groups. These results suggest that habitual rowing exercise in older men is associated with high muscle power and aerobic capacity, and favourable blood lipid profile without affecting arterial stiffness or plasma levels of endotheline-1 and NO. 相似文献
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Yasushi Takata Anri Inaki Takafumi Mochizuki Hitoaki Numata Takeshi Oshima 《Journal of sports sciences》2016,34(20):2011-2017
Changes in muscle activity were evaluated by positron emission tomography–computed tomography (PET–CT) after performing part 2 of the Fédération Internationale de Football Association’s 11+ programme (11+) for 4 weeks. Eleven males performed part 2 of the 11+ for 20 min before and after 37 MBq of 18F-fluorodeoxyglucose (FDG) was injected intravenously. PET–CT images were obtained 50 min after FDG injection. The participants were then instructed to perform part 2 of the 11+ 3 times per week for 4 consecutive weeks, after which another set of PET–CT images was obtained following the same procedure. Regions of interest were defined within 30 muscles. The standardised uptake value (SUV) of FDG by muscle tissue per unit volume was calculated, and FDG accumulation was compared between pre- and post-training PET–CT results. Performing part 2 of the 11+ for 4 weeks increased mean SUV in the sartorius, semimembranosus, biceps femoris, abductor hallucis, and flexor hallucis brevis muscles (P < 0.05). In conclusion, routinely performing part 2 of the 11+ for 4 weeks increased glucose uptake related to muscle activity in the hamstrings and hallux muscles. We speculate that there is some possibility of this change of muscle activity contributing to a decrease in sports-related injuries. 相似文献
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