排序方式： 共有25条查询结果，搜索用时 15 毫秒
1.
Takashi Umeda Kazuhiro Suzukawa Ippei Takahashi Yousuke Yamamoto Masaru Tanabe Arata Kojima 《Journal of sports sciences》2013,31(9):897-904
Abstract To clarify the physical and mental fatigue caused by intense exercise and the relationship between the two types of fatigue, we examined changes in anthropometric and biochemical variables, neutrophil function, and the Profile of Mood States (POMS) questionnaire in 13 female university judoists attending a one-week training camp. Blood glucose, total cholesterol, haemoglobin, leukocyte count, IgG, and phagocytic activity all decreased after the training camp compared with baseline (P ≤ 0.046). Aspartate aminotransferase, lactate dehydrogenase, creatine kinase, and neutrophil oxidative burst activity increased after the training camp (P ≤ 0.007). Of the POMS scores, that for Fatigue increased after the training camp (P = 0.041) and that for Vigour decreased (P = 0.042). The changes in several POMS scores correlated with the changes in blood biochemical variables. In particular, the change in Total mood disturbance was negatively associated with changes in myogenic enzymes (P ≤ 0.032). Our results suggest that intense exercise during training camps for female judoists leads to the appearance and accumulation of mental and physical fatigue, which are related to each other. 相似文献
2.
3.
The purpose of this study was to investigate the effect of the racket mass and the rate of strokes on the kinematics and kinetics of the trunk and the racket arm in the table tennis topspin backhand. Eight male Division I collegiate table tennis players hit topspin backhands against topspin balls projected at 75 balls · min?1 and 35 balls · min?1 using three rackets varying in mass of 153.5, 176 and 201.5 g. A motion capture system was used to obtain trunk and racket arm motion data. The joint torques of the racket arm were determined using inverse dynamics. The racket mass did not significantly affect all the trunk and racket arm kinematics and kinetics examined except for the wrist dorsiflexion torque, which was significantly larger for the large mass racket than for the small mass racket. The racket speed at impact was significantly lower for the high ball frequency than for the low ball frequency. This was probably because pelvis and upper trunk axial rotations tended to be more restricted for the high ball frequency. The result highlights one of the advantages of playing close to the table and making the rally speed fast. 相似文献
4.
The purpose of this study was to examine the adequacy of "multi-age" classification systems in youth sports with a specific focus on the unisex multi-age-groupings used by USA Swimming. In addition, we offer an analytical rationale for the multi-age-groupings and potential alternatives. We examined the top 100 US swim performances for three years (2005, 2006, and 2007) for girls and boys in 15 age-groups (7 to 20 years and a singular group of 21 years and older). Data for each age and sex were pooled over the three years and means were calculated for each of seven competitive swim events. Swim times differed among each age up to the 14-year age-group in girls (F (14,30885) = 183.9, P < 0.01, Cohen's d = 1.19-3.72, large effect) and 16-year age-group in boys (F (14,30885) = 308.7, P < 0.01, Cohen's d = 0.81-3.64, large effect) for all events. Age-related differences in swim times continued later in boys than girls likely due to differences between the sexes in timing of growth and maturation. Because of the differences in swim performance in contemporary multi-age-groups, stratifying swimmers by a single age is the best means to ensure competitive fairness and equality, although there is no rationale for swimmers under the age of 8 years to compete in separate unisex competitive groups. 相似文献
5.
因特网已成为全球性的信息环境，我们可以跨越时空获取信息资源。然而，当用户使用自身社区的术语和元数据方案来检索信息时，现在的因特网技术还没有成熟到能提供专业信息设施。元数据担任很重要的角色来帮助实现社区导向的信息环境。本文进行了两项案例研究，包括建立专业主题词表(用于图书馆和图书馆信息科学资源主题网关(LIS)的核心主题词表)和用于地方社区门户网站的主题词表。从这两个案例可以看出小型的主题词表对专业服务是非常有用的，并且维护工作对词表的建立和应用是至关紧要的。为了在网络上建立专业信息环境，我们必须解决对元数据方案来说相悖的两个需求——社区中的专业化(或者本地化)和社区之间的互操作。这篇文章提供了一个概念模型来理解解决这个问题所要涉及的诸多方面。 相似文献
6.
Shigeo Sugimoto 《档案与原稿》2014,42(1):61-72
This paper discusses some key issues for digital archives and metadata in a networked information environment to keep our community memory for the future. The paper is based primarily on the experiences and lessons learnt by the author from his research activities on metadata and digital archives. The author participated in a study group on digital archives hosted by the Ministry of Internal Affairs and Communications of the Japanese Government from February 2011 to March 2012. The group discussed the promotion of digital archives in Japan, particularly at memory institutions. The Great East Japan Earthquake of 11 March 2011 caused serious damage in the north-eastern part of Japan, especially the Pacific coastal regions. This disaster significantly affected the discussions of the group. The basic lesson that the author learned is that digital archives built on a robust information environment are essential for keeping our community memory safe for the future. Not only do the primary digital resources need to be properly maintained and preserved for the future but also secondary resources, metadata and meta-metadata. We need to use Linked Open Data technologies to enhance the usability of such digital resources in the archives. 相似文献
7.
Kojima Y 《Child development》2000,71(6):1640-1647
Characteristics of three maternal regulating behaviors--(1) reference to one sibling's actions or emotional states toward the other sibling, (2) encouragement of sibling interactions, (3) distraction of one sibling's attention away from the other sibling-and their associations with children's positive and negative behaviors toward their siblings were investigated through semistructured home observations for 40 sibling pairs (1-4 years, 2-8 years) and their mothers in Japanese families. Maternal regulating behaviors were observed more frequently when the younger sibling was still in an early developmental stage in the preschool years, although the findings were modest. The older sibling's negative behaviors toward the younger sibling positively correlated with maternal distraction toward the younger; alternatively, the younger sibling's negative behaviors do not correlate with maternal distraction but do correlate with maternal encouragement directed toward the older sibling. Reliable associations were found between maternal regulating behaviors and prosocial exchanges between siblings; maternal reference to the younger sibling's actions or emotional states directed toward the older sibling was associated with the older sibling's positive behavior toward the younger sibling. Maternal regulating behaviors during mother-sibling triadic interactions were associated with the quality of sibling relationships. 相似文献
8.
9.
Abstract The purpose of this study was to examine the adequacy of “multi-age” classification systems in youth sports with a specific focus on the unisex multi-age-groupings used by USA Swimming. In addition, we offer an analytical rationale for the multi-age-groupings and potential alternatives. We examined the top 100 US swim performances for three years (2005, 2006, and 2007) for girls and boys in 15 age-groups (7 to 20 years and a singular group of 21 years and older). Data for each age and sex were pooled over the three years and means were calculated for each of seven competitive swim events. Swim times differed among each age up to the 14-year age-group in girls (F 14,30885 = 183.9, P < 0.01, Cohen's d = 1.19–3.72, large effect) and 16-year age-group in boys (F 14,30885 = 308.7, P < 0.01, Cohen's d = 0.81–3.64, large effect) for all events. Age-related differences in swim times continued later in boys than girls likely due to differences between the sexes in timing of growth and maturation. Because of the differences in swim performance in contemporary multi-age-groups, stratifying swimmers by a single age is the best means to ensure competitive fairness and equality, although there is no rationale for swimmers under the age of 8 years to compete in separate unisex competitive groups. 相似文献
10.
Kinetics of the upper limb during table tennis topspin forehands in advanced and intermediate players 总被引：1，自引：0，他引：1
Iino Y Kojima T 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(4):361-377
The purpose of this study was to determine the significance of mechanical energy generation and transfer in the upper limb in generating the racket speed during table tennis topspin forehands. Nine advanced and eight intermediate table tennis players performed the forehand stroke at maximum effort against light and heavy backspin balls. Five high-speed video cameras operating at 200 fps were used to record the motions of the upper body of the players. The joint forces and torques of the racket arm were determined with inverse dynamics, and the amount of mechanical energy generated and transferred in the arm was determined. The shoulder internal rotation torque exerted by advanced players was significantly larger than that exerted by the intermediate players. Owing to a larger shoulder internal rotation torque, the advanced players transferred mechanical energy from the trunk of the body to the upper arm at a higher rate than the intermediate players could. Regression of the racket speed at ball impact on the energy transfer to the upper arm suggests that increase in the energy transfer may be an important factor for enabling intermediate players to generate a higher racket speed at impact in topspin forehands. 相似文献