排序方式： 共有11条查询结果，搜索用时 156 毫秒
1.
Sentaro Koshida Takanori Ishii Tadamitsu Matsuda Toshihiko Hashimoto 《European Journal of Sport Science》2017,17(4):417-424
It is generally accepted that proper learning of the breakfall technique during early judo training is essential for attenuating the risk of judo-related head injury. Therefore, it is critical to understand the kinematics and head injury risks of breakfall motion to design a more safe and effective judo teaching paradigm that results in reduction of injury risk. We aimed to investigate the biomechanics of judo backward breakfalls by comparing osoto-gari and ouchi-gari in novice judokas. Twelve male novice judokas (age: 21.3 years, SD?=?0.6 years; height: 1.74?m, SD?=?0.04?m; body weight: 71.3, SD?=?6.4?kg; body mass index: 23.5, SD?=?2.3) volunteered to participate in this study. The kinematic data of the breakfall motion for both osoto-gari and ouchi-gari were collected using a three-dimensional motion analysis technique (200?Hz). We observed significant differences between the movement patterns for the two techniques, especially in the lower extremity movements. In addition, a significantly greater peak extension momentum (osoto-gari: 1.29, SD?=?0.23?kg?m2?s?1; ouchi-gari: 0.84, SD?=?0.29?kg?m2?s?1) and lower head position along the vertical axis (osoto-gari: 0.18, SD?=?0.05?m; ouchi-gari: 0.31, SD?=?0.08?m) with a large effect size were found in the breakfall for osoto-gari. Our results suggest that a different paradigm is needed for effectively teaching each breakfall technique that will enable us to substantially lower the risk of judo-related head injuries in novice judokas. 相似文献
2.
Toshiaki Miyamoto Saya Hashimoto Hideya Yanamoto Mai Ikawa Yoshiki Nakano Takashi Sekiyama 《European Journal of Sport Science》2018,18(8):1119-1127
Purpose: Brain-derived neurotrophic factor (BDNF) is well known for its potential to promote brain plasticity. It has been proposed that combining cognitive and physical exercise (CCPE) may have the potential to generate more synergistic benefits in cognitive function than either cognitive exercise (CE) or physical exercise (PE) alone. The purpose of this study was to examine acute responses of peripheral BDNF levels and cognitive performance to CE, PE, and CCPE.Methods: Thirteen healthy adult men participated in four experimental sessions; a 30-min CE, a 30-min cycling PE at an intensity of 60% peak oxygen uptake, a 30-min CCPE at the same intensity as PE, and a 30-min session of complete rest. Plasma BDNF levels and cognitive performance were measured before and after each session.Results: Both PE and CCPE significantly increased plasma BDNF levels (p?p?≥?.05), and there was no significant difference in peripheral BDNF levels between PE and CCPE (p?≥?.05). No session induced a significant change in cognitive performance (p?≥?.05).Conclusions: Our study suggests that CE and PE have different responses of peripheral BDNF levels and that CCPE had no additional or synergistic effect on peripheral BDNF levels compared with PE alone. This study offers further insights into the potential mechanisms underlying the respective roles of CE, PE, and CCPE for peripheral BDNF levels and cognitive performance. 相似文献
3.
This paper presents a data envelopment analysis (DEA)/Malmquist index methodology for measuring the change in R&D efficiency at both firm and industry levels. Letting each of ten firms in each year be a separate decision-making unit, and employing one input and three outputs in a DEA case of R&D activity input-output lag, we measure “total factor R&D efficiency” change of Japanese pharmaceutical firms for decade 1983-1992 as defined by the period of R&D input. Decomposing Malmquist index into catch-up and frontier shift components and using “cumulative indices” proposed in this study, we evaluate R&D efficiency change for each firm and empirically show that R&D efficiency of Japanese pharmaceutical industry has almost monotonically gotten worse throughout the study decade. 相似文献
4.
5.
Sentaro Koshida Takanori Ishii Tadamitsu Matsuda Toshihiko Hashimoto 《Journal of sports sciences》2017,35(11):1059-1065
Previous studies suggest that increasing the skill level of judokas will decrease the number of head injuries sustained during judo. However, the kinematics are poorly understood, making it difficult to establish an effective breakfall teaching programme. Therefore, we studied the kinematic parameters of breakfall for osoto-gari to identify the risk of judo-related head injuries by comparing experienced and novice judokas. This information will provide insight into developing a better prevention plan for judo-related head injuries.
A total of 10 experienced and 12 novice judokas volunteered to participate in this study. The kinematic data of the breakfall motion for osoto-gari were collected using a three-dimensional motion analysis technique (200 Hz).
We observed a significantly higher peak neck extension momentum in the novice group than in the experienced group. This suggests that neck extension momentum during breakfall is associated with the risk of head injuries during judo. In addition, the novice judokas demonstrated a significantly greater flexed pattern in the trunk and hip movement than the experienced judokas (P < 0.05). The results suggest that the trunk and lower extremity motion are important kinematic parameters that determine the skill level in performing the breakfall for osoto-gari. 相似文献
6.
In 1972 a longitudinal study was launched in one of the largest department store chains in Japan. The purpose of this study was to investigate the managerial career development of the newly hired college graduates. The research design required repeated monitoring of a newcomer's progress within the organization at seven different points in time over a three-year period. The study investigated basic questions concerning the process of managerial career development: (1) Why do some people achieve a higher level of management progress during the early period of their organizational career, while others do not? (2) What are the important indicators of management development during the formative years in business? (3) How accurately can development in management be predicted? (4) What are the organizational and personal consequences of managerial development? Over the three-year period of this study data were collected on 80 newly hired college graduates. Two models that have been used to understand the process of early management development in the United States were tested. Results were compatible with these models. Performance at the end of three years was found to be significantly related to both initially assessed potential (assessment model) and developed working relationships (vertical exchange model). Other professional and organizational outcomes were significantly related to developed working relationships. The implications of this cultural generality are discussed. 相似文献
7.
In this study, the stabilizability irrespective of the bounds of uncertain parameters and time delays is investigated for linear uncertain delay systems. For uncertain systems without delays, a linear time-varying or time-invariant uncertain system has been shown to be stabilizable independent of the bounds of uncertain variations if and only if the system has a particular geometric configuration called an antisymmetric stepwise configuration (ASC) or a generalized antisymmetric stepwise configuration (GASC), respectively. In this study, fundamental approaches to investigating the stabilizability of delay systems with specific uncertainty structures such as ASCs or GASCs are presented. For a class of 3-dimensional systems, it is shown here that if a linear time-varying or time-invariant uncertain delay system has an ASC or a GASC, respectively, then the system can be stabilized, however large the given bounds of delays and uncertain parameters might be. 相似文献
8.
Toshihiko Hashimoto Takanori Ishii Naoyuki Okada Masahiro Itoh 《Journal of sports sciences》2015,33(13):1356-1365
In this study, eight judo athletes who are major candidates for the Japan national team were recruited as participants. Kinematic analysis of exemplary ukemi techniques was carried out using two throws, o-soto-gari, a throw linked to frequent injury, and o-uchi-gari. The aim of this study was to kinematically quantify the timing patterns of exemplary ukemi techniques and to obtain kinematic information of the head, in a sequence of ukemi from the onset of the throw to the completion of ukemi. The results indicated that the vertical velocity with which the uke’s head decelerated was reduced by increasing the body surface exposed to the collision with the tatami and by increasing the elapsed time. In particular, overall upper limb contact with the tatami is greatly associated with deceleration. In o-soto-gari, the impulsive force on the faller’s head as the head reached the lowest point was 204.82 ± 19.95 kg m · s–2 while in o-uchi-gari it was 118.46 ± 63.62 kg m · s–2, z = ?1.75, P = 0.08, and it did present a large-sized effect with r = 0.78. These findings indicate that the exemplary o-soto-gari as compared to o-uchi-gari is the technique that causes more significant damage to the uke’s head. 相似文献
9.
Shinichi Demura Shunsuke Yamaji Takayuki Murooka Masuo Nakai 《Journal of sports sciences》2013,31(8):881-889
Abstract We previously proposed two predictive equations of visceral fat area applicable in a field setting (Demura & Sato, 2007a, 2007b). One uses the fat mass of the trunk measured by bioelectrical impedance as the main predictor (equation 1) and the other uses internal fat mass estimated from several anthropometric variables (equation 2). In this study, we examined the inter- and intra-individual accuracy of estimated values using these equations after 8 weeks of exercise training. Participants were 42 Japanese adults aged 42.7 ± 10.3 years (22 males, 20 females). Visceral fat area, body composition, and blood biochemistry were measured at baseline and after 8 weeks. There were no significant differences in reference visceral fat area measured by computed tomography and visceral fat area predicted by the equations either at baseline or after 8 weeks, and the values were highly consistent (equation 1: baseline R 2 = 0.829, after R 2 = 0.860; equation 2: baseline R 2 = 0.832; after R 2 = 0.850). No significant relationship was observed between the reference and change in visceral fat area for equation 1 (males: r = 0.272, P > 0.05; females: r = 0.428, P > 0.05), but there was a significant relationship for females with equation 2 (males: r = 0.279, P > 0.05; females: r = 0.474, P <0.05). Our findings indicate that these equations have high inter-individual consistency but low intra-individual consistency with the reference and are of limited use for the longitudinal evaluation of visceral fat area. 相似文献
10.
Noriko Hashimoto Kaori Ushitora Mari Morioka Terunori Motegi Kazue Tanaka Mieko Tashiro 《Sex education》2017,17(4):386-398
This study aimed to evaluate changes in the attitudes of Japan’s post-war youth towards gender equality and sexuality, and to examine whether these attitudes bore a relationship to school education. Different generations were delineated based on changes in courses of study and year of birth, and semi-structured interviews were conducted enquiring about experiences and opinions during secondary school days. We examined sexuality education in both junior high school (ages 12–15 years) and high school (15–18 years), views on premarital sex, views on marriage and divorce, and views on gender roles. Fifty-three survey participants were involved in the study: 30 women and 23 men. The characteristics of each generation were examined in relation to corresponding courses of study and the textbooks available in junior high and high schools, identifying both homologies and differences between the messages courses contained and the expressed beliefs of different generations of informants. 相似文献