著者

梶田 和宏 川村 卓 島田 一志 金堀 哲也 八木 快

出版者

日本コーチング学会

雑誌

コーチング学研究 (ISSN:21851646)

巻号頁・発行日

vol.32, no.2, pp.171-187, 2019-03-20 (Released:2019-09-02)

参考文献数

55

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This study clarifies the features of throwing motion to second base of professional baseball catchers.Eleven catchers of two Nippon Professional Baseball Organization teams were participants. Using the highest confidence data among analytical trials for throwing time, we defined it as ‘the time required from catching until ball arriving at second base with shortest time’. Following five characteristic features were revealed. 1) In time parameter, professional catchers have a difference in motion time (the time required from catching to release in amateur catchers), especially during the beginning phase having a relation with duration time (arrival time from the ball release to the second base), the throwing phase having a relation with the throwing time and release speed (speed average of ball speed of 3 frames after releasing the ball), and the grip changing phase having a relation with motion time. 2) Further, professional catchers have a tradeoff relationship between the motion time and the duration time as well as amateur catchers; and, particularly good professional catchers can shorten the duration time even while shortening motion time leading to shortening of the throwing time. 3) In stride parameter, professional catchers have a difference in the length of the pivot foot in amateur catchers, especially, the X component has a relation with the motion time while the Y component has a relation with the duration time, and the stride length is likewise; there was no relationship between all the items. 4) In release parameter, professional catchers maintain a higher projection height of the ball than amateur catchers and maintain the tendency of the projection angle to be lower, improving the throwing accuracy, especially the elevation angle is related to the duration time and the release speed, but the azimuth angle is likewise; there was no relationship between all the items. 5) In center of gravity of the body, professional catchers have a relation with the movement speed of the center of gravity of the body and the release speed as well as amateur catchers, but the moving distance of center of gravity of the body is likewise; there was no relationship between all the items.

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

波戸 謙太 金堀 哲也 蔭山 雅洋 八木 快 谷川 聡 川村 卓

出版者

日本コーチング学会

雑誌

コーチング学研究 (ISSN:21851646)

巻号頁・発行日

vol.36, no.2, pp.159-176, 2023-03-20 (Released:2023-03-31)

参考文献数

44

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This study delineates the common characteristics of pitching motion in professional baseball players (Top and Minor groups) by focusing on their upper body. With an aim to gain insight into the development of athletic abilities, the pitching motion of the Top group was compared with the Minor group, resulting in the clarification of upper limb issues in the Minor group and amateur pitchers. The subjects were 47 pitchers belonging to the Nippon Professional Baseball (NPB). The experiment was a fastball pitch with maximum effort. The analyzed trial was the highest ball velocity (average ball velocity 38.9 ± 1.8 m/s). Post-analysis, the following commonalities and differences were identified. (1) There is a commonality in the sizeable external rotation of the shoulder joint during MER (Maximum External Rotation), which is considered a factor in pitching speed compared to amateur pitchers. However, after evaluating the professional baseball pitchers, it was suggested that this movement had a low influence on the ball velocity. (2) There was a commonality in the movements in which the maximum shoulder horizontal adduction angular velocity was more significant than the upper trunk angular velocity. (3) However, in terms of differences among professional baseball pitchers, the Top group pitchers had a greater horizontal adduction angular velocity of the shoulder joint during MER and a more significant extension angular velocity of the elbow joint during REL (Ball Release) by suppressing the forward tilt angular velocity of the trunk during MER.

著者

梶田 和宏 川村 卓 島田 一志 八木 快

出版者

一般社団法人 日本体育学会

雑誌

日本体育学会大会予稿集

巻号頁・発行日

vol.66, pp.319-320, 2015