著者
Koji MUROFUSHI Shinji Sakurai Koji Umegaki Kazutoshi Kobayashi
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.3, pp.116-128, 2005 (Released:2008-01-23)
参考文献数
18
被引用文献数
7 12

The aim of this study was to compare the radius of curvature and the estimated head speed as measured by sensors attached to a hammer with those calculated by video image analysis. The participant was the Japanese record holder(83m47). He threw a hammer with sensors which measured the force exerted along the length of the hammer cable using a tension meter made of a metal plate to which strain gauges were affixed, and the angular velocity perpendicular to the hammer cable using two IC accelerometers whose axes were aligned together with the hammer cable. The radius and speed obtained using the sensors were similar to those obtained from video analysis in values, but were slightly out of phase. This is because measuring the angular velocity by sensors eliminates translational motion and only produces results for rotational motion. The length of time required to obtain these results was shortened by the use of a hammer with sensors. Therefore, the system using sensors attached to a hammer will enable athletes and coaches to interpret the data about each throw while it is still fresh in their minds.
著者
Sookyoung Park Seunghoon Lee Yunkyung Hong Youngjeon Lee Kanghui Park Dongkwang Shin Sang-Rae Lee Kyu-Tae Chang Yonggeun Hong
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.10, pp.50-57, 2012 (Released:2012-09-13)
参考文献数
35

This study compared the range of hallux valgus angle (HVA) deformity between basketball players and same aged non-basketball players as controls. The participants included 21 basketball players (9 males, 12 females, mean age 18 years) and 36 age-matched college students (19 males, 17 females, mean age 20 years) who served as controls. After direct palpation of the first metatarsal and proximal phalange, we measured the HVA deformity using a photographic approach in the women basketball players and a goniometer for the men basketball players and all controls. The HVA was greater in basketball players than in the controls. Among female basketball players, the HVA was significantly greater in guards compared with forwards and centers. In conclusion, playing basketball may increase the HVA. The greater increase in HVA among guards might arise because they are required to make diagonal and horizontal movements that increase the burden on the foot. In general insole or ergonomic shoes could reduce pain, improved walking ability, and hallux valgus angle for prophylactic or therapeutic approaches. Therefore, an appropriate preventive interventional program should be developed.
著者
吉田 和人 山田 耕司 玉城 将 内藤 久士 加賀 勝
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
体育学研究 (ISSN:04846710)
巻号頁・発行日
vol.59, no.1, pp.227-236, 2014
被引用文献数
1

The rotation speed of the ball spin has been considered a key factor in winning table tennis matches. This study quantified the rotation speed (rotations per second: rps) of service balls delivered by quarter-finalists in the 2009 World Table Tennis Championships. Ball services were recorded during the quarter-finals of both the men's and women's singles, involving 4 matches and 8 players per gender, using a high-speed video camera (1000 fps) for calculation of the rotation speed, and a standard video camera (30 fps) for distinguishing players and aces (including those touched by the receiver). Eventually, the rotation speeds of 329 services were calculated, and these ranged from 13.7 to 62.5 rps. For men, 50-60 rps was the most frequent (40.0%) range of the rotation speeds, while for women, the corresponding range was 40-50 rps (43.8%); the average (±SD) rotation speed was significantly greater for men than for women (46.0±9.0 vs. 39.2±9.3 rps, p<0.001). The fastest rotation speed was 62.5 rps for both genders. Chinese men produced a slower rotation speed than did other men (43.5±8.9 vs. 51.0±6.8 rps, p<0.001). For women, however, the rotation speed was similar between Chinese players and the others (39.9±10.2 vs. 38.5±8.2 rps). The rotation speeds of aces were scattered over a wide range of 37.0-58.8 rps for men and 27.8-62.5 rps for women, implying a weak association between aces and fast rotation. These pioneering data may help clarify some of the technical and tactical aspects of table tennis, and can be used to develop training and game strategies for successful performance.<br>
著者
Susumu Sato Shinichi Demura Noriaki Sugano Hajime Mikami Tetsuhiko Ohuchi
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.6, pp.113-119, 2008-12-30 (Released:2009-11-05)
参考文献数
27
被引用文献数
1 3

This study aimed to examine the characteristics of handedness in Japanese adults based on gender differences, the presence of left-handed (LH) relatives and experiences with the forced conversion of handedness. Subjects were comprised of 4668 Japanese adults ranging from 15 to 29 years of age (3127 males 18.8±1.8 years old and 1541 females 18.8±1.4 years old). We investigated their subjective handedness, the presence and type of LH relatives, and their experiences with forced conversion of handedness. Although there was no gender difference in the incidence of “innate LH (a subject who had experienced forced conversion of handedness, or a LH subject without experience in the forced conversion)”, females underwent more forced conversion of handedness and had a higher incidence of subjects whose handedness changed from LH to RH. There was no significant difference in the proportion of forced conversion based on the presence of LH relatives, but the incidence of innate LH was higher in subjects with LH relatives and the proportion of LH subjects who remained unchanged after forced conversion was also higher in subjects with LH relatives. Among the subjects with LH relatives, the incidence of current LH was significantly higher in subjects with LH grandparents or parents than siblings. These findings may suggest that forced conversion may influence a gender difference in the incidence of LH. In addition, the presence of LH relatives genetically and environmentally (imitation) influences handedness, and the influence is greater in parents than siblings.
著者
Maki Itoh Mary A. Hums Akiko Arai Etsuko Ogasawara
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
pp.201630, (Released:2018-03-02)
参考文献数
22

The purpose of this qualitative study was to (a) determine structural barriers that must be overcome to cultivate female leaders and coaches and (b) study the development of a support system for female leaders and coaches. This study relied on in-depth interviews as the primary means of collecting data. Formal semi-structured interviews were conducted with seven former or currently active female Paralympians, including some who were current coaches. After analyzing the participants' responses, five distinct themes emerged: (a) social identity, (b) challenges of “double minority status” as women and persons with a disability, (c) underrepresentation of women as Paralympic coaches, (d) athletes wanting to be coaches indicating they needed formal training, and (e) current coaches feeling overwhelmed by task requirements not related directly to working with athletes. The first of these relate to realizing identity and the other four to overcoming barriers. The results offer insight into the career challenges and career perceptions of coaches and also former or currently active female Paralympians. The results provide researchers with insight into the status of careers of women in a segment of the sport industry, the Paralympic Movement, which has not yet been thoroughly explored.
著者
山田 理恵
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
体育学研究 (ISSN:04846710)
巻号頁・発行日
2015

The game of <i>dakyugi</i> (literally, "hitting-ball-game"), involving three components of play (hitting a ball, throwing a ball, and pushing of opponents), is a traditional stick game that has been passed down to the present in Kuwana City (Mie Prefecture).<br>  The purposes of this study were to examine the process of the game's revival and cultural features, and to clarify the significance of <i>dakyugi</i> as a traditional sport in regional development through sports. The materials used in this study were mainly collected through fieldwork at the Rikkyo Area Great Meeting and interviews with members of the preservation association, as well as investigation of historical sources.<br>  In the Meiji era, <i>dakyugi</i> had been played as a bravery game by boys in the Kuwana <i>gijyuku</i>, which inherited the idea of the Rikkyou-kan, a school in the fiefdom of Kuwana. Although <i>dakyugi</i> declined after World War II, it was revived to mark the 150th anniversary of Matsudaira Sadanobu's death in May 1978.<br>  Today, <i>dakyugi</i> is performed at the Kuwana Municipal Rikkyo Elementary School supported by the <i>Dakyugi</i> Preservation Association. Boys and girls of the school play the game at the athletic meeting held jointly by the school and Rikkyo area community. The game of <i>dakyugi</i> in Kuwana is noteworthy in promoting the behavior pattern and style of <i>samurai</i> culture that characterized the Edo era. In addition, <i>dakyugi</i> is considered to play an important role in the revitalization of provincial cities and in the establishment of local regional identity.<br>  The significance of traditional Japanese culture is emphasized in the present school education program. The current study indicates that traditional Japanese sport culture can play an important role in regional development in Japan.<br>
著者
Lawrence P. Lai Jeffrey S. Shilt John S. Georgy
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
pp.201420, (Released:2015-12-14)
参考文献数
27

Herpes Zoster, also known as Shingles, is an eruption of latent Varicella Zoster viral particles which classically leads to a dermatomal skin eruption. While the causes of this reactivation are yet unknown, Shingles usually affects older individuals or those who are immunocompromised due to other disease processes or pharmacotherapy following organ transplant. We report the unique case of a world class triathlete who developed a painful dermatomal rash following a period of particularly intense training, travel, and competition. His training schedule for three months following the illness and return to competition is documented. The athlete's subsequent period of underperformance and profound fatigue suggest an inadequate recovery period. Review of the literature reveals a paucity of information describing an appropriate return to training and competition.
著者
大峰 光博
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
体育学研究 (ISSN:04846710)
巻号頁・発行日
vol.60, no.2, pp.489-495, 2015

This study investigated trash talk among soccer players, focusing on whether it actually disturbed playing performance and whether the ability to ignore such trash talk was an asset to the game. The "Laws of the Game" of soccer stipulate that any player who uses "offensive, insulting or abusive language and/or gestures" should be dismissed from the field. Therefore, any penalty imposed on players for such behavior can be interpreted as sanctions for prohibited act.<br>   Furthermore, any game in which offensive or insulting remark are used was considered by reference to Kawatani's opinion about excellence and "failed athletic contest". When a referee penalizes a player appropriately for such behavior, it is suggested that the game has not "failed". On the other hand, as such behavior is often difficult for a referee to notice, an appropriate penalty is sometimes not administered. Therefore, it is suggested that an offensive or insulting remark is an act that indirectly destroys the ethos of a game. I conclude that the ability to ignore trash talk is not an asset to the game in principle, but that such ability is practically necessary.<br>
著者
高岡 治子
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
体育学研究 (ISSN:04846710)
巻号頁・発行日
vol.55, no.2, pp.525-538, 2010

Japanese married women only began participating widely in sports after the Tokyo Olympic Games in 1964. It is often said that sports activities by housewives indicated their liberation from isolated domestic life, thereby promoting gender equality. However, close examination of the systemic characteristics of the 'Mothers' Volleyball' movement (based on its ideology, competition rules and the nature of its routine activities) has shown that these activities possess both a recycling structure that releases housewives from their homes temporarily and reflects the participants' 'housewifeliness', thereby reinforcing the separation of roles between the sexes.<br> In order to clarify by whom and for what purpose this recycling structure was created, this paper focuses on the organizing bodies (sponsor organizations, supporting companies and other bodies that organized and ran the national championships, incorporating the systemic characteristics of Mothers' Volleyball), analyzing the reasons for their involvement with the movement and the benefits they derived from it. The results show that the periodic reflection of housewifeliness, which housewives needed in order to continue in their role as housewives, was necessary for the economic and social benefit of all the organizations involved, and that this is why these organizations committed themselves to the movement.<br> Participating in sports freed housewives from the routine of daily home life, and activities such as helping to organize competitions promoted their socialization and changed their image from that of 'isolated housewife' to 'sporting housewife' and further to 'independent housewife'. The recycling structure mentioned earlier can therefore be thought of as being a directional spiral, and the organizing bodies that ran the national championships can be said to be its drivers.<br> This spiral, which helped to reproduce 'housewifeliness', supplied society with good-quality labour for sustaining Japan's rapid economic growth, which was a political issue in the 1970s. The participation of housewives in sports as one of the activities of parent-teacher associations and women's associations can also be said to have contributed to local revitalization, another political topic at that time. Meanwhile, making sports one of their routine, repeated activities made housewives' lives more satisfying, so that Mothers' Volleyball acted as a medium for the formation of a conjugate relationship between housewives and society.<br>
著者
Jung-uk Won Kaoru Kitamura
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.4, pp.233-251, 2006 (Released:2008-01-25)
参考文献数
56
被引用文献数
4 8

The purpose of this study was to examine motivational factors affecting consumption behavior of K-league and J-league spectators, and their predictability to explain it. We found that 10 motivational factors significantly, but not sufficiently explained the current attendance frequency of the K-league spectators, whereas these factors well predicted their future consumption behavior. It was considered that there is great potential in the K-league spectator market. The results of the J-league spectators indicated that team identification and vicarious achievement were strong predictors to explain the variance in the game attendance frequency of the J-league spectators, and these results were consistent with the results of Mahony, et al., (2002). However, we found a new predictor (social interaction) to explain this variance. Also, we found that escape was a new positive predictor to explain the intention to attend future games of the K-league and J-league spectators, and escape, player, and team identification were related to the future merchandise consumption of both the K-league and J-league spectators.
著者
MUROFUSHI Koji Sakurai Shinji Umegaki Koji Kobayashi Kazutoshi
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.3, pp.116-128, 2005
被引用文献数
12

The aim of this study was to compare the radius of curvature and the estimated head speed as measured by sensors attached to a hammer with those calculated by video image analysis. The participant was the Japanese record holder(83m47). He threw a hammer with sensors which measured the force exerted along the length of the hammer cable using a tension meter made of a metal plate to which strain gauges were affixed, and the angular velocity perpendicular to the hammer cable using two IC accelerometers whose axes were aligned together with the hammer cable. The radius and speed obtained using the sensors were similar to those obtained from video analysis in values, but were slightly out of phase. This is because measuring the angular velocity by sensors eliminates translational motion and only produces results for rotational motion. The length of time required to obtain these results was shortened by the use of a hammer with sensors. Therefore, the system using sensors attached to a hammer will enable athletes and coaches to interpret the data about each throw while it is still fresh in their minds.
著者
Emika Kato Toshiaki Oda Kentaro Chino Toshiyuki Kurihara Toshihiko Nagayoshi Tetsuo Fukunaga Yasuo Kawakami
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.3, no.Special_Issue_2005, pp.218-225, 2005 (Released:2008-01-23)
参考文献数
19
被引用文献数
14 20

Flexibility is often evaluated from the joint range of motion (ROM), but the mechanisms underlying gender differences in joint ROM have not been elucidated. The purpose of this study was to investigate the factors influencing the difference in ankle joint ROM between men and women with respect to the extensibility of muscle-tendon complex. Eighteen men (21-26 yr, 66.4±6.0kg, 173.7±7.4cm mean±SD) and 12 women (19-27yr, 52.9±4.8kg, 163.4±4.3cm) participated in this study. Each subject was seated with the knee extended, and the ankle joint was attached to a foot plate, by which the ankle joint was passively dorsiflexed with torque gradually increasing from zero to a value at which the passive loading to the ankle joint was just tolerable for each subject. During the passive loading, real-time ultrasonogram was taken to track the movement of MTJ (muscle-tendon junction of the gastrocnemius medialis and Achilles tendon) as the elongation of muscle belly (dMus). The change of MTC (muscle-tendon complex) length (dMTC) during the passive dorsiflexion was estimated from changes in ankle joint angle. Tendon elongation (dTen) was calculated by subtracting dMus from dMTC. There was no significant difference in normalized passive torque during passive dorsiflexion between men and women. Women were more flexible, i.e., they demonstrated greater dMTC, which was accompanied by greater dTen at lower torque levels. However, dMus was not different between men and women. It was concluded that gender difference in the joint ROM at the ankle reflects more compliant Achilles tendon in women than in men.
著者
Senshi Fukashiro Thor F. Besier Rod Barrett Jodie Cochrane Akinori Nagano David G. Lloyd
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.3, no.Special_Issue_2005, pp.272-279, 2005 (Released:2008-01-23)
参考文献数
29
被引用文献数
22 20

The purpose of this study was to perform a detailed kinematic, kinetic, and electromyographic comparison of maximal effort horizontal and vertical jumping. It was of particular interest to identify factors responsible for the control of jump direction. Eight male subjects performed maximal horizontal jumps (HJ) and vertical jumps (VJ) from a standing posture with a counter movement. Three-dimensional motion of the trunk, pelvis, and bilateral thigh, shank, and foot segments were recorded together with bilateral ground reaction forces and electromyographic (EMG) activity from seven right leg muscles. Relative to the VJ, the trunk is displaced further forward at the beginning of the HJ, through greater ankle joint dorsiflexion and knee extension. The activity of the biarticular rectus femoris and hamstrings were adapted to jump direction and helped to tune the hip and knee joint torques to the requirements of the task. The primary difference in joint torques between the two jumps was for the knee joint, with the extension moment reduced in the HJ, consistent with differences in activation levels of the biarticular rectus femoris and hamstrings. Activity of the mono-articular knee extensors was adapted to jump direction in terms of timing rather than peak amplitude. Overall results of this study suggest that jump direction is controlled by a combination of trunk orientation at the beginning of the push-off and the relative activation levels of the biarticular rectus femoris and hamstring muscles during the push-off.
著者
馬場 崇豪 和田 幸洋 伊藤 章
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
体育学研究 (ISSN:04846710)
巻号頁・発行日
vol.45, no.2, pp.186-200, 2000-03-10 (Released:2017-09-27)
被引用文献数
12 3

The muscular activity pattern, function and maximal contraction velocity during the starting dash and sprint running at maximal velocity were studied. The subjects were five adult male sprinters, whose sprint running movements in the sagittal plain were analyzed (100 fps) from videotape recordings made with a high-speed catera. The ground reaction forces and EMGs of eight leg muscles were also recorded. Changes in length from the origin to the insertion (muscle-tendon complex : MTC) of the eight leg muscles were calculated using several methods reported by Grieve et al. (1978), Hawkins and Hull (1990), Visser et al. (1990) and Jacobs and Van Ingen Schenau (1993). The muscular activity pattern and the maximal contraction velocity were investigate from the change in length of the MTC when the EMG activity was observed. The turnover velocity of the muscular activity pattern in the stretch-shortening cycle (SSC) was calculated from the acceleration of the contraction. Also the hip, knee and ankle joint torques were calculated, and the following results were obtained.1. Changes in muscular activity pattern and maximal contraction velocity during the starting dash During the first half of the swing period, the m.gluteus maximus exhibited shortening activity, the m.rectus femoris exhibited stretching activity and the m.iliopsoas exhibited SSC muscular activity. The m.vastus lateralis exhibited shortening activity during the last half of the swing period and stretching activity during the first half of the foot contact period. The m.biceps femoris exhibited SSC muscular activity from the middle of the swing period to the middle of the foot contact period. The m.gastrocnemius and m.soleus exhibited SSC muscular activity during the foot contact period. Above all, the maximal shortening stretching velocity, and the turnover velocity increased with increasing sprint running velocity after the start, except for the shortening velocity of the m.gastrocnemius and m.soleus, and the stretching velocity of the m.vastus lateralis, whose contraction velocity stayed almost constant. 2. Muscular activity and function during sprint running at maximal velocity During the first half of the swing period, the m.rectus femoris produced knee extension troque by stretching activity which functioned to reduce the knee flexion force which occurred through the joint force related to hip flexion torque. During the latter half of the swing period, knee flexion torque developed as a by-product from the m.biceps femoris, which serves as a hip extensor. On the other hand, the knee extension force which occurred through the joint force related to hip extension torque, the momentum required to extend the knee joint, and the knee extension torque which was produced by the shortening activity of the m.vastus lateralis were observed during the same period. Therefore, the knee extension movement observed from the outside occurred as a result of the total of these forces. The m.tibialis anterior acted to offset the ankle extension force which occurred through the joint force related to knee extension torque during the first half of the swing period, and the ankle extension torque developed during the latter half of the swing period preparation for foot contact by the m.gastrocnemius an m.soleus.
著者
Kenji Tauchi Toshinori Endo Mitsugi Ogata Akifumi Matsuo Shigeo Iso
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.6, pp.78-84, 2008 (Released:2008-08-09)
参考文献数
13
被引用文献数
10 9

The purpose of this study was to clarify the characteristics of jump ability in elite adolescent male athletes for the purpose of comparing them to healthy coeval males by referring to the results reported by Endo, et al., (2007). One hundred and twenty elite male athletes (alpine skiers, fencers, soccer players, track and field sprinters and jumpers, and weight lifters) aged 18 to 24 yrs and 316 healthy males aged 19 and 20 yrs performed countermovement jumps (CMJ) and five- repeated rebound jumps (5RJ) on a mat switch system. CMJ and 5RJ abilities were evaluated by jump height and RJ-index (=jump height/ground contact time), respectively. Although the jump height in CMJ and the RJ-index in 5RJ developed from ages 6 to 18 yrs, these values reached a plateau between the ages of 18 and 20 yrs in healthy males, elite athletes further developed after age 18. When the values for the healthy males in the present study were added to the results obtained for 1137 boys by Endo, et al., (2007), the regression line and correlation coefficient between jump height in CMJ and the RJ-index in 5RJ changed only slightly. However, the values for elite adolescent athletes tended to appear in the upper right from the population ages of 6 to 20 yrs; moreover, the scattering exhibited wide variation. The results revealed that although jump ability in healthy adolescent males changed little after age 18, jump ability in elite coeval athletes were superior after age 18 and that individual differences increased according to the length of specific training in each sport.
著者
Yutaka Shimizu Michiyoshi Ae Norihisa Fujii Hiroyuki Koyama
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
pp.201817, (Released:2018-10-25)
参考文献数
24

The purposes of this study were to classify jumping techniques in the preparatory and take-off phases of elite male long jumpers in official competitions by using a cluster analysis and to identify biomechanical characteristics of classified technique types. The preparatory and take-off motions of 29 elite male long jumpers in official competitions were collected three-dimensionally using two high-speed cameras. Their jumps were classified into four types of jumping technique by using the Ward’s method of cluster analysis with the take-off angle as a parameter. The four types were named the Horizontal (H-type), Semi-Horizontal (SH-type), Semi-Vertical (SV-type), and Vertical (V-type) types. There were no significant differences in jumping distance among the types. H-type jumpers were characterised by a forward lean of the trunk and a larger swing leg knee flexion during the preparatory phase. V-type jumpers flexed the knee joint of the support leg more during support phase in the last stride and showed a larger backward lean of the trunk at touchdown of the take-off foot. SH- and SV-types were located between H-type and V-type jumpers. This classification will help coaches and jumpers to select appropriate techniques.
著者
Yoichi Katsumata
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
pp.201805, (Released:2018-10-18)
参考文献数
17

This study examined the influence of the relative age effect (RAE) on the competitive level and playing position of male elementary school Japanese baseball players. The sample comprised the following: (1) 506 general male baseball players (BP) who were aged 11–12 (sixth grade) and who had not competed at the prefectural level and (2) 189 regionally selected players (SP) who were aged 11–12 (sixth grade) and who had been selected to compete at the prefectural level or a higher level. The subjects were divided into two groups based on their birth months (Semester 1 (S1): April–September and Semester 2 (S2): October–March). Prevalence ratio for each semester was calculated. Pearson’s chi-square test was employed to examine the RAE of each group and each playing position. Results of a chi-square test at each competitive level showed that the SP group was statistically significant (S1>S2) but the BP group was not. The chi-square test for the pitcher and the fielder (catcher, infielder, and outfielder) positions revealed statistical significance in the SP group (S1>S2), with only the pitcher position showing statistical significance in the BP group (S1>S2). The results indicated that the RAE was higher in more competitive level junior baseball players and that the RAE exerted a stronger influence on the pitcher position than on the fielder positions.
著者
図子 浩二 高松 薫
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
体育学研究 (ISSN:04846710)
巻号頁・発行日
vol.40, no.1, pp.29-39, 1995-05-10 (Released:2017-09-27)
被引用文献数
5 3

Rebound drop jump index [RDJ_&ltindex&gt=(1/8・g・RDJt_a^2)/RDJt_c] was developed to evaluate the ability to perform the ballistic stretch. shortening cycle (SSC) movement. The RDJ_&ltindex&gt consists of ability to jump higher (RDJt_a) and that to shorten the contact time (RDJt_c) in rebound drop jump (RDJ), a typical SSC movement. The former is affected by leg strength and counter movement jump ability but the factors affecting the latter case have not yet been well established. This study examined the factors to shorten the contact time with special reference to two important views, i.e. work done by the lower limb joints and anticipation of the landing. 1. Relationships between work done by the lower limb joints and RDJ_&ltindex&gt, RDJt_c, and RDJt_a in RDJ from height of 0.3m were examined in ten college male athletes. There was a significant correlation between the ratio of negative work at the ankle to total work done by the lower limb joints and RDJ_&ltindex&gt (r=0.726, p&lt0.05), and RDJt_c (r=-0.823, p&lt0.01) but not RDJt_a (r=0.226,ns). Furthermore, there was no significant correlation between the ratio of negative work at the ankle and maximum plantar flexion strength (r=-0.329,ns). These results suggested that the rate of energy absorption at the ankle joint in former contact phase was one important factor to shorten the contact time in RDJ but not affected by plantar flexion strength. 2. RDJ_&ltindex&gt, RDJt_c and RDJt_a in two RDJs with or without visual information to inhibit temporal and spatial anticipation of landing were compared in six college male athletes. As compared without and with visual information, RDJt_c was longer, RDJt_a was shorter and RDJ_&ltindex&gt was lower, significantly. These changes were greater in subjects showing the higher RDJ_&ltindex&gt than those showing the lower RDJ_&ltindex&gt. Furthermore, changes of RDJ_&ltindex&gt, RDJt_c and RDJt_a in series of nine RDJs without visual information at thirty seconds of rest intervals were compared between subject A showing high RDJ_&ltindex&gt and subject B showing low RDJ_&ltindex&gt. RDJt_c decreased and RDJt_a increased slightly, and RDJ_&ltindex&gt increased by repeated trials even without visual information in subject A but not in subject B. These results suggested that temporal and spatial anticipation of the landing were another important factors to shorten the contact time in RDJ. These finding seemed to be beneficial for establishing strength and power training methods for jumper and ballgame players who are required ballistic stretch-shortening cycle movement.
著者
Noriaki Usui Motoki Okumura Kazutoshi Kudo
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
International Journal of Sport and Health Science (ISSN:13481509)
巻号頁・発行日
vol.16, pp.19-26, 2018 (Released:2018-07-24)
参考文献数
18
被引用文献数
1

To succeed in many sports, players must not only adjust their movements during execution in response to environmental changes, but also switch to different movements altogether. Previous studies have implicated executive functions in movement switching ability. We aimed to clarify expertise differences in movement adjustment and switching, and compared performance on three tasks of target striking between expert and intermediate kendo players as participants. Task 1 was a simple strike, whereby participants struck targets at one position; Task 2 was an adjusted strike, whereby participants struck targets at three positions in a random order. Task 3 was strike-defense switching, whereby participants struck targets as in Task 2 while were also required to switch to defense when an opponent made a counter-strike. That is, the participants were required accurate strike in Task 1 and 2 close to the kendo practices, and were required accurate strike and defense in Task 3 close to the real matches. We found no differences in strike movement time and accuracy in any of the tasks between groups. However, expert players were able to execute successful strike-defense switching in Task 3, whereas intermediate players were not. These results suggest that an expertise difference exists in executive functions, and that it is essential for players to practice focused on acquisition of switching skills in order to further improve their performance.
著者
池本 淳一
出版者
Japan Society of Physical Education, Health and Sport Sciences
雑誌
体育学研究 (ISSN:04846710)
巻号頁・発行日
vol.59, no.2, pp.529-547, 2014

This paper focuses on the position of "Ju-ken" matches and their promoter, Kenji Kano, in Japanese boxing history. A "Ju-ken" match was a match between a judoist and a boxer, and such bouts were held from the middle of the Taisho era to the early Showa era in Kobe, Tokyo and Osaka. The main organizer of these matches was the "International Ju-ken club", whose owner Kenji Kano was the nephew of Jigoro Kano. This study divides the history of Ju-ken into three periods, each with respective features.<br>   The first period was from October 1919 to April 1921. Ju-ken at this time was intended to reform judo into a competitive sport through fighting with boxing. Although judo had been well established at that time, it was facing a challenge due to loss of its spirit and form as a martial art during the process of sportification. Jigoro Kano, the founder of Judo, was unhappy with this change. By studying boxing, karate, aikido, stick fighting and other martial arts, he aimed at creating a 'Martial Art Judo'. His nephew Kenji Kano pursued martial art-oriented judo as well, but his approach to reconstructing judo as a martial art was through mixed martial arts games, the "Ju-ken match".<br>   The middle period was from May 1921 to March 1925, when Ju-ken evolved into a spectator sport that encapsulated the struggle for superiority in terms of nationality and ethnicity. Because Kodokan prohibited their members from participating in any mixed-martial arts match from April 1921, Ju-ken became a spectator sport. In addition, after charity matches following the Great Kanto Earthquake, in order to bring more excitement to the game, Ju-ken heightened the opposition and rivalry based on the nationalities and ethnicities of the athletes.<br>   The final period was from April 1925 to August 1931, when Ju-ken changed into a show that was intended to provoke nationalistic emotions among the audience. After the development of "normal" boxing, Ju-ken held normal boxing matches in their games and adopted new boxing-like rules. These new rules and the point systems put foreign boxers at a disadvantage when fighting against Japanese judoists, ensuring that Japanese would always defeat foreigners.<br>   Finally, through assimilation of knowledge and focusing on boxing, this study argues that Ju-ken matches created a background for localization of modern boxing in Japan.<br>