著者

太田 和希 吉田 拓矢 小野 響也 前村 公彦 谷川 聡

出版者

一般社団法人 日本体育・スポーツ・健康学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.67, pp.793-808, 2022 (Released:2022-09-29)

参考文献数

38

被引用文献数

2

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This study investigated the relationships between pelvic behavior and impulse of ground reaction force as well as leg backward swing velocity during the acceleration phase and full speed phase of sprint running. Eleven male sprinters performed 30-m and 60-m sprints from a crouching start at maximal effort. Threedimensional motion analysis was performed to investigate the relationships between pelvic behavior and impulse of ground reaction force as well as leg backward swing velocity during the acceleration phase and full speed phase of sprinting running. The angular displacement of the pelvic free leg side lateral flexion in the frontal plane showed a significant positive correlation with the propulsion and vertical impulse during the acceleration phase. Also, the lumbosacral free leg side lateral flexion angular impulse showed a significant positive correlation with the propulsion and vertical impulse during the acceleration phase. Additionally, the lumbosacral free leg side torsion angular impulse showed a significant positive correlation with the peak value of the free leg backward swing velocity during the full speed phase. Therefore, the results obtained during the acceleration phase suggest that the pelvic free leg side lateral flexion was able to increase the propulsion and vertical impulse, whereas during the full speed phase, the pelvic free leg side rotation contributed to increasing the free leg backward swing velocity.

著者

清野 隼

出版者

一般社団法人 日本体育・スポーツ・健康学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.67, pp.557-575, 2022 (Released:2022-07-12)

参考文献数

36

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The purpose of this research was to explore the characteristics required of a leader for adventure journeys. The study comprised 2 parts. In Part 1, a semi-structured interview was conducted with the Arctic adventurer Yasunaga Ogita to clarify the concepts he regarded as essential for an expedition leader. This yielded an understanding of the characteristics of adventure journeys, i.e. repeatedly taking active steps, while accepting uncertainty and freedom. On that basis, it was shown to be vital to identify and manage risks through objective assessment, and to make choices based on active observation. In Part 2, a participant-observation method was used, focusing on Yasunaga Ogita, as well as 8 6th-grade elementary school students and 7 staff members who participated in a 100-mile expedition. As practical knowledge, Part 2 clarified the actions required for achieving an adventure journey based on the expert knowledge of Mr. Ogita revealed in Part 1. This clarified the characteristics of risk management and acceptance of the freedom of children, and demonstrated that “instruction”, “education”, “acceptance”, “response”, and “delegation of decision-making to the team” should be properly applied based on active observation. It was concluded that an effective expedition leader needs to repeatedly engage in selfregulation, manage the contradictory elements of risk and freedom, and adapt to change. To develop such characteristics, it is crucial to build up experience while actively going into the field and engaging in group action.

著者

小澤 哲也 金沢 翔一 長野 康平 浅川 孝太 中村 和彦

出版者

一般社団法人 日本体育・スポーツ・健康学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.66, pp.533-549, 2021 (Released:2021-08-18)

参考文献数

47

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The first objective of this study was to develop a course unit plan for physical fitness in the lower grades of elementary school, in which traditional play as exemplified by exercises for physical fitness are used as teaching material to create various movements (Study I). The second objective was to conduct classes using traditional play as teaching material based on the course unit plan, in order to gain an understanding of the fundamental movements that appear and the amount of physical exercise during the class (Study II). Study I: A total of 163 traditional play physical activities were selected from prior studies and related publications. 22 elementary school third graders were examined for the fundamental movements included in 42 of the traditional play physical activities. The median number of such fundamental movements that appeared was 3 (minimum: 1, maximum: 8). From the survey results, traditional play physical activities were selected from among those that had no bias in their fundamental movements and had rules that could easily be changed and levels of difficulty that could easily be adjusted, and a course unit plan was developed taking into account the ease of class preparation by teachers. Study II: A total of 5 lessons based on the course unit plan were given to 23 elementary school second graders. The fundamental movements were measured using observational methods, and the number of steps was measured objectively using an accelerometer. The fundamental movements observed and the number of steps measured during the course unit were compared with the age-appropriate standards for motor skills. The results revealed the following: 1) Of the 28 fundamental movements that were set, 25 were observed during the course unit. 2) There was a high frequency of fundamental movements common to many of the traditional play physical activities. 3) The mean number of steps in the physical education classes with diverse movements using traditional play physical activities as teaching materials for lower grades of elementary school was 2343.6±586.1. 4) There were no differences in the number of steps in any of the classes between the higher-ranked and the lower-ranked children. These results suggest that from the perspective of fundamental movements and amount of physical exercise, creating various movements using traditional play physical activities as teaching materials may be satisfactory.

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

4

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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

中嶋 哲也

出版者

一般社団法人 日本体育・スポーツ・健康学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.59, no.2, pp.721-744, 2014 (Released:2014-12-20)

参考文献数

71

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This study investigates the emergence of the concept of “sportification of judo” in Japan, focusing on the process of “student judo” in relation to the competition between the First Higher School (“Ichikoh”) and the Second Higher School (“Nikoh”) in 1918, up until formation of the Association of Judo by the Four Imperial Universities in 1928. Jigorō Kanō, the father of judo, was dissatisfied that Nikoh had overused ground techniques against Ichikoh in 1918, and in June 1924, Kodokan published a revised set of umpiring rules to control the use of ground techniques in student judo.   However, Tsunetane Oda, the manager of Nikoh judo club, criticized Kanō, and advocated that ground techniques were a valid combat method. Oda finally compromised, because Takeshi Sakuraba, one of Kanō's best pupils, refuted Oda's proposal. However, it was the first time that Kodokan had been publicly criticized by someone concerned with student judo, and this seems to have been a trigger for student judo to become independent from Kodokan.   In parallel with the emergence of the democracy movement after World War I, Judo came to be regarded as extremely outmoded, and judo practitioners began to place more emphasis on theory rather than actual competition. Kanō interceded with the Tokyo Gakusei Judo Rengōkai (Tokyo Student Judo Association, “TGJR”), and in 1924 persuaded the TGJR to let their umpire rules reflect the revised umpire rules. However, the Imperial University of Tokyo (IUT) rebelled against this movement, and left the TGJR. The IUT then appealed to each of the Imperial Universities, and held the Teidai Taikai (the Four Imperial Universities Competition, “FIUC”) to encourage nationwide spread of the Kosen Judo Taikai (National High School and Vocational School Judo Competition, which was hosted by Kyoto Imperial University, “KJT”). The Imperial University Judo Association, which hosted the FIUC, then abandoned the combat characteristics that were advocated by Kodokan, with the aim of representing judo as a “sport”.   One of the reasons why Kibisaburō Sasaki criticized Kodokan was that he had been treated coldly by Kanō and Kyūzō Mifune at the Shūki Kōhaku Shiai (a contest between two Kodokan groups) in November 1922, because he had used ground techniques frequently. Moreover, Sasaki as a member of the IUT judo club had experienced the withdrawal of the IUT from the TGJR, and the holding of the FIUC. Therefore, Sasaki criticized Kodokan while student judo was being organized. Sasaki claimed that “sportification” did not confer any new value on the principles of Kodokan judo. Kanō criticized the over-use of ground techniques by KJT and the FIUC, which lacked a combat system. However, Sasaki considered that Kanō's opinion was a long-established custom, and insisted that the FIUC was a sports competition. Thus, the claim made by Sasaki meant that the FIUC had become independent from Kodokan judo.

著者

日比野 幹生 舟橋 弘晃 石井 隆憲

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

pp.19046, (Released:2020-01-20)

著者

重松 良祐 鎌田 真光

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

pp.13001, (Released:2013-05-13)

参考文献数

11

被引用文献数

7 1

著者

奥村 拓朗 伊藤 雅広 近藤 智靖 今関 豊一 滝沢 洋平 岡出 美則

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

pp.20018, (Released:2020-08-31)

被引用文献数

1

著者

石川 叶絵 遠藤 俊典 田内 健二

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

pp.20033, (Released:2020-10-28)

著者

前田 奎 大山卞 圭悟 関 慶太郎 水島 淳 広瀬 健一 尾縣 貢

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.64, no.1, pp.21-36, 2019-06-17 (Released:2019-06-25)

参考文献数

38

被引用文献数

1

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The purpose of this study was to investigate, using path analysis, causal relationships among motion factors for achieving a high release velocity in the male discus throw. The throwing motions of 61 male discus throwers were analyzed using three-dimensional motion analysis. Variables such as release velocity, velocities gained by each body segment, body segment velocity, body angle and angular velocity were obtained. The path model indicating the causal relationships among these factors was constructed by path analysis. The main results were as follows: Influences of velocities gained by each body segment on release velocity were largest for the arm, followed in order by the trunk and legs. Motion factors such as weight shift, acquisition of the velocity of the center of gravity, sweeping the legs, rotations of the hip and shoulder, twisting and untwisting of the trunk, acquisition of the velocity of the right knee and extension of the left knee had direct or indirect influences on the velocities gained by each body segment. Motion factors in the path model revealed causal relationships along the time sequence of the throwing motion. In addition, the path model in this study indicated the cause and effect structure of the throwing motion by which Japanese male discus throwers were able to achieve a high release velocity. The results of this study can be utilized for technical coaching of the discus throw based on causal relationships.

著者

有冨 公教 外山 美樹

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.64, no.1, pp.315-334, 2019-06-17 (Released:2019-06-25)

参考文献数

31

被引用文献数

1

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The purposes of this study were to examine the functions of thought during a sport task performance from the perspectives of objective recognition by researchers and subjective recognition by the participants themselves. Participants (n=30) were assigned to two different incentive presentation conditions (acquisition or loss according to achievement of the task) and were required to complete a dart throwing task while stating their thoughts aloud while executing it. A protocol analysis of the utterances revealed the following 10 thought categories: internal focus, external focus, psychological self-control, cognition of anxiety and tension, positive self-evaluation or emotion, negative self-evaluation or emotion, irrelevant thought, active attitude, passive attitude, and performance analysis. Six participants who completed the experimental task were interviewed and the data were examined using Personal Attitude Construct (PAC) analysis. In the interview, participants were required to generate the original thought categories from their own protocol and to interpret the thought contents and functions in the performance. Furthermore, cluster analysis with a similarity distance matrix of the generated thought categories revealed the overall structure of thought in each individual. These results showed that recognition of the contents and functions of thought during performance of a sport differed between the researchers and the participants. According to this, for example, even though thought is generally considered as negative thinking, depending on the individuals involved in the task, it could be recognized as positive thinking. The results of this study suggested that, to understand the function of thought during a sports performance, it is necessary to understand the context in which an individual is placed and to base the interpretation on the meaning and experience for the individual.

著者

佐々木 究

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.54, no.2, pp.279-291, 2009-12-10 (Released:2010-02-13)

参考文献数

36

被引用文献数

1 1

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This paper is part of a study performed to clarify certain aspects of primitive thought related to physical education (PE), as outlined in the work of Jean-Jacques Rousseau.Some studies of Rousseau have focused on PE, but in my view these are not based on the positive foundation, and there is no reference to the term “physical education (éducation physique)” in his works. Nevertheless, it is possible to demonstrate connections between Rousseau and PE. It is evident that the “father of modern PE”, GutsMuths, was influenced by Rousseau, and many discussions in this field have, in fact, been based on Rousseau. This study focuses not on PE itself, but on a prototype concept that is recognizable in Rousseau's works.For this purpose, this paper attempts to analyze the context, especially public education focusing on the human body. In general, the terms “human body (corps)” and “education (éducation)” are understood as the elements of PE, and discussion of public education can be seen as one of the bases of Rousseau's thoughts about education, containing some important descriptions about the human body.The main points presented in this paper are as follow:Body exercise (exercices corporels) in public education, which has been accepted as the “PE of Rousseau”, is an approach to education with two purposes: moral and physical. Exercise is based on “negative education” aiming at the “child”, which is one of the main concepts of Rousseau's education thought. Furthermore, some value is placed on the whole process, where public education goes on to developing patriotism (l'amour de la patrie) in children (i.e. future citizens). Finally, exercise, a method of education, is balanced between the demand for public education and the restriction imposed by negative education.

著者

森丘 保典 杉田 正明 松尾 彰文 岡田 英孝 阿江 通良 小林 寛道

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.45, no.3, pp.414-421, 2000-05-10 (Released:2017-09-27)

被引用文献数

1

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This study was conducted to clarify the relationship between features of change in velocity and performance of world class athletes in the men's 400-m hurdle race(400mH).Nine final races of 400mH were videotaped with several video cameras panning from the start to the finish at 60 fields/s.After the time indication had been superimposed on each field of the VTR images, the time at touchdown immediately after hurdling was obtained.Using the flash of the starter's gun recorded on the VTR image, each hurdle touchdown time from the start, and each section thme(from each hurdle to the next)was obtained.The results of regression analysis showed a significantly high correlation (r=0.90, p<0.001)between 400mH performance and mean section velocity from the 5th to the 8th hurdle(H5-8), and a significant correlation(r=-0.61, p<0.05)between 400mH performance and te rate of deceleration in H5-8.These results indicate that in 400mH it is important to avoid decreasing velocity and to maintain a high velocity in H5-8 of the race in order to attain a high performance.

著者

内藤 景 苅山 靖 宮代 賢治 山元 康平 尾縣 貢 谷川 聡

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.58, no.2, pp.523-538, 2013 (Released:2013-12-07)

参考文献数

32

被引用文献数

1

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The purpose of this study was to clarify the step characteristics during the acceleration phase (0—30 m) of a 100-m sprint with reference to the step-type of sprinters. 59 male collegiate sprinters (season best time: 10.68±0.22 s) were recorded running in 100-m races using 10 high-speed video cameras (300 fps). The step variables, such as step-frequency (SF), step-length (SL), contact time, and flight time of each step in the acceleration phase (0—30 m) and maximum speed phase (30—60 m) were calculated. Cluster analysis was used to classify the subjects according to step-type as indicators for the ratio of SF and SL in the 30—60 m section. In addition, each of the step-type groups was divided into two sub-groups (good and poor sprinters) according to the mean speed in the 30—60 m section. The main results were as follows: (1) Sprinters were classifiable into 3 step-type groups; SL-type (n=22), SF-type (n=24), and Mid-type (n=13). (2) Among these groups, there were no differences in the 100-m race times and mean speeds during the 0—30, 30—60, and 60—100 m sections, although SL-type sprinters were taller and had a higher SLindex than SF-type sprinters. SF-type sprinters took a larger numbers of steps over the 100-m distance and showed a higher SFindex than SL-type and Mid-type sprinters. (3) In the 0—30 m and 30—60 m sections, the contact and flight times of SL-type sprinters were longer than those of SF-type sprinters. (4) In SL-type sprinters, the SF of good sprinters was higher than that of poor sprinters at the 5th step, and the SL of good sprinters was longer than that of poor sprinters from the 7th to 15th steps, and in the 30—60 m section. (5) SF-type sprinters showed no significant differences in the SL, but the SF of good sprinters was higher than that of poor sprinters from the 7th to 16th steps and in the 30—60 m section. These results indicate that there are differences in step characteristics during the acceleration phase according to step-type, and that the step characteristics during the acceleration phase may affect the acceleration ability needed to develop a maximum sprint speed. These findings could be useful for devising training methods for improvement of 100-m sprint performance according to step-type.

著者

内山 治樹 池田 英治 吉田 健司 町田 洋介 網野 友雄 柏倉 秀徳

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

pp.16078, (Released:2018-07-23)

参考文献数

66

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The purpose of this study was to clarify the causal relationship between the “flow of a game” in basketball, defined as “the situation in which 4 periods, which consist of a division time of 10 minutes, advance gradually while having an influence on each other”, and its outcome, focusing on the interrelationships of the 4 periods. For this purpose, a hypothesis was established that the “flow of a game,” in which “factors causing changes in conditions” cannot be overlooked, consists of 4 periods, each creating opportunities that finally affect the outcome. In order to test this hypothesis, an analysis was performed of 1044 periods in 261 games in Japan’s strongest university league, the Kanto Men’s First Division League, based on the following 3 perspectives: (1) the importance of each period; (2) the mutual dependency among the periods; and (3) the relationship between the difference in cumulative scoring and outcome. The results were subjected to logistic regression analysis and covariance structure analysis, and the following 3 points were clarified: (1) Periods that influenced the outcome were the first, third and fourth, ranked in importance as third > first > fourth > second. (2) With regard to mutual dependency among the periods, the points difference in the preceding period in the sequence “first → second (cumulative),” “second (cumulative) → third (cumulative), “third (cumulative) →“fourth” created an opportunity in the following period. (3) A cumulative score difference of less than 8 points by the end of the third period was associated with a high potential for coming back to win. These findings should be applicable to coaching in various games under the official rules of the FIBA as new practical guidelines for closely analyzing the causal relationships between the unique “flow of a game” and outcomes in basketball that take place over 4 periods.

著者

小倉 圭 川村 卓 金堀 哲也 野本 尭希 八木 快 小野寺 和也

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.62, no.2, pp.511-522, 2017 (Released:2017-12-19)

参考文献数

25

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The purpose of this study was to clarify the types of step adjustment performed by baseball infielders for catching a grounder in relation to skill level. The subjects were 18 amateur baseball infielders, whose fielding motions were videotaped using 2 high-speed video cameras (300 Hz). The 3-dimensional coordinates of both the toes and the ball were obtained using the DLT method. The top 9 subjects who showed small variations in the grounding point of both feet when adopting the catching posture were defined as a high-performance group, and the bottom 9 subjects were defined as an intermediate-performance group. The results obtained were as follows:  1) Baseball infielders modified each grounding point from 4 steps to 1 step before catching in order to acquire the most appropriate catching point, and the final step was highly reproducible.  2) The high-performance group showed a significantly smaller standard deviation in the 1 step before the grounding point than the intermediate-performance group.  3) In the high-performance group, there was a positive correlation between the standard deviation of step length 1 step before and the standard deviation of the grounding point from 5 steps to 2 steps before.  These results suggest it is important to reduce variations in the grounding point 1 step before by earlier perception of the error in the front-to-rear direction of the grounding point. These results could provide important insight for coaches or trainers attempting to improve the performance of infielders when catching a grounder.

著者

阿江 数通 小池 関也 藤井 範久 阿江 通良 川村 卓 金堀 哲也

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.62, no.2, pp.559-574, 2017 (Released:2017-12-19)

参考文献数

46

被引用文献数

1

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The purpose of this study was to compare the kinematic characteristics of the upper body between baseball tee batting and pitched ball batting in order to gain basic knowledge for improvement of batting skill. Ten male collegiate baseball players (age: 20.7±1.1 yr; height: 1.75±0.05 m; body mass: 76.3±7.1 kg; athletic career: 12.7±2.7 yr) participated. They performed 2 kinds of batting: tee batting (TB) and machine-pitch batting (MB) using a pitching machine (approximate ball speed 33.3 m/s), which were set at middle ball height for the strike zone. Three-dimensional coordinate data were acquired with a motion capture system. Kinematic variables such as maximum bat-head speed, swing time, bat angle, joint angles of the upper limbs, and segment angle of the upper trunk were calculated. Differences between TB and MB were analyzed statistically using paired t-test (p<0.05). The maximum bat-head speed was significantly greater in TB than in MB, but swing times divided into 2 phases showed no significant differences between MB and TB. In the first half of the swing, the bat inclination angle was significantly larger in MB than in TB. The joint angles of the barrel-side shoulder abduction, knob-side shoulder adduction and internal rotation were significantly larger in MB than in TB, and those of the barrel-side shoulder internal rotation and individual elbow pronations were significantly larger in TB than in MB. The clockwise rotational angle of the upper trunk was significantly larger in TB than in MB. In the last half of the swing, the joint angles of the barrel-side shoulder abduction, knob-side shoulder flexion and adduction were significantly larger in MB than in TB, and that of the knob-side elbow pronation was significantly larger in TB than in MB. The changes in upper body movement in MB affected the radius of rotation of the bat about the vertical axis to control the bat easily. The movements in the last half of the swing largely resulted from those in the first half of the swing, and did not contribute to timing adjustment. These results indicate that the initial configuration of the bat and upper limbs, and movements at the beginning of the bat swing contribute to the timing adjustment of the bat for a pitched ball. The results of the present study suggest that it could be useful to pay attention to the movement of the bat and upper body in the first half of the swing as TB practice in order to improve timing adjustment.

著者

城所 収二 矢内 利政

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

vol.62, no.2, pp.475-490, 2017 (Released:2017-12-19)

参考文献数

16

被引用文献数

1

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The horizontal direction in which a batted ball travels is determined primarily by 2 factors: the horizontal angle of the bat at ball impact (first mechanism) and the interaction between the vertical inclination angle of the bat and the position of the ball impact along the short axis of the bat (second mechanism). As the bat is generally inclined vertically at the moment of ball impact (the head is positioned lower than the grip end), the second mechanism must cause an opposite influence on the horizontal trajectory of the batted ball when a grounder and a fly-ball are compared. The purposes of this study were two-fold: (a) to compare the contributions of the 2 mechanisms to the horizontal direction of batted balls between grounders and fly-balls and (b) to determine the relationship between the contribution of each mechanism and the speed of the batted ball. Sixteen collegiate baseball players were asked to hit balls delivered by a pitching machine aiming towards the same field and the opposite field for 4 trials each. The motions of the ball and the bat around the moment of ball impact were recorded using 2 high-speed cameras (1000 fps). The contributions of the 2 mechanisms to the horizontal directions of the batted balls were calculated from the following variables: the trajectory of the pitched and batted ball, projection angles of the bat in the horizontal plane (horizontal bat angle) and the vertical plane (vertical bat angle), and the angle of the line of impact from the horizontal at ball impact (line of impact angle). The first mechanism contributed 40% or more on average to both the same- and opposite-field hitting of grounders and fly-balls projected towards the fair territory. For fly-balls to the same field and grounders to the opposite field, the contribution of the first mechanism was particularly high (same/fly ball: 118.6±35.2%, opposite/grounder: 109.5±17.8%), and the impact surface of the bat faced toward the batted ball direction. The contribution of the second mechanism was greater for grounders to the same field and fly-balls to the opposite field than the others (same/grounder: 46.7±23.3%, opposite/fly ball: 50.6±49.2%). The speed of the batted ball was negatively correlated with the contribution of the second mechanism (r=−0.73, p<0.01). Therefore, in order to hit a ball with higher speed, a batter should adjust the timing of impact to use the first mechanism, and should strike near the center of the ball.

著者

新井 春生

出版者

一般社団法人 日本体育学会

雑誌

体育学研究

巻号頁・発行日

vol.14, no.5, 1970

著者

村井 友樹 李 燦雨

出版者

一般社団法人 日本体育学会

雑誌

体育学研究 (ISSN:04846710)

巻号頁・発行日

pp.15036, (Released:2015-08-26)

参考文献数

63

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The aim of this study was to clarify the background and features of implementation of the Nationwide Swimming Training for Conscription Candidates (NSTCC). The tasks of the study were to elucidate the 1) background, 2) preparation, 3) contents, and 4) results of NSTCC implementation.  The results of this study were as follows:  1) After the outbreak of the Sino-Japanese war, the problem of a lack of swimming ability was observed among soldiers, so municipal governments and the Ministry of Health and Welfare turned to the STCC as the solution.  2) As the Sino-Japanese war was prolonged, the Ministry of Health and Welfare integrated the STCC, which had previously been conducted as a separate program, into one implementation throughout the whole country.  3) After the outbreak of the Pacific War, the situation was worsening, and the lack of swimming ability in ground forces became obvious. To resolve this problem, the Ministry of Health and Welfare decided on a comprehensive implementation program, which was planned at the beginning of 1943, through the NSTCC.  4) The NSTCC was supported by the Imperial Rule Assistance Association and its neighborhood associations. Since swimming training on a nationwide scale was not compulsory for all conscription candidates, the Imperial Rule Assistance Association mobilized conscription candidates to participate in training through different propagandas.  5) The National Physical Training Association trained coaches for each prefecture and each implementation district. Most coaches in each implemental district were school teachers.  6) In was recommended that the NSTCC be conducted using swimming pools, but a number of implementation districts did so in seas, rivers, or lakes.  7) The first half of the NSTCC was intended to cultivate the ability to float, on the assumption that this ability was basic training in order for beginners to master swimming.  8) During the second half of the NSTCC, attaining the technique of sidestroke or breaststroke was preferred. Each implementation district was able to choose a stroke (sidestroke or breaststroke).  9) Disciplinary training was highly regarded in the NSTCC.  10) As 95% of all participants were able to swim for more than 10 meters upon completing training, the NSTCC was judged to have been effective in eliminating a lack of swimming ability.