著者

神事 努 森下 義隆 平山 大作

出版者

日本バイオメカニクス学会

雑誌

バイオメカニクス研究 : 日本バイオメカニクス学会機関誌 (ISSN:13431706)

巻号頁・発行日

vol.16, no.1, pp.41-46, 2012

著者

柴田 翔平 鳴尾 丈司 加瀬 悠人 稲毛 正也 山本 道治 森 正樹 浦川 一雄 廣瀬 圭 神事 努

出版者

一般社団法人 日本機械学会

雑誌

シンポジウム: スポーツ・アンド・ヒューマン・ダイナミクス講演論文集 2018 (ISSN:24329509)

巻号頁・発行日

pp.A-18, 2018 (Released:2019-05-25)

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The purpose of this study is to examine the accuracy of the system analyzing pitching data using baseball-type sensor (MAQ) and to measure kinematic parameter (ball velocity, spin rate, and spin axis) of baseball pitches by various pitchers. The accuracy of the developed system using a 3D motion analysis system and the high-speed cameras were examined. The spin axis of pitched ball was calculated from data of 12-axis sensor using the sensor fusion by extended Kalman Filter. The ball velocity and spin rate calculated by MAQ and the 3D motion analysis system showed similar values (ball velocity: r = 0.95 spin rate: r = 0.90). In several data, it was indicated that the spin axis calculated by MAQ, the 3D motion analysis system, and the high-speed camera showed similar values. In addition, there was a correlation between ball velocity and spin rate over the velocity range from 6.7 m/s to 41.0 m/s (n=188). From these results, the developed system can be used to evaluate baseball pitching skill with high accuracy.

著者

神事 努 桜井 伸二 清水 卓也 鈴木 康博 Tsutomu JINJI Shinji SAKURAI Takuya SHIMIZU Yasuhiro SUZUKI

雑誌

中京大学体育学論叢 = Research journal of physical education Chukyo University (ISSN:02887339)

巻号頁・発行日

vol.49, no.1, pp.21-27, 2008-01-01

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It has been reported that the spin axis of a pitched baseball differs between adult pitchers and youth pitchers (Tezuka and Himeno 2001). However, that information was based on visual observation, and has not been determined quantitatively. The purpose of this study was to investigate the ball spin orientation and spin rate of youth pitchers compared with those for adult pitchers. In addition, the development of the throwing motion and factors in the determination of spin rate were discussed. Fourteen youth baseball pitchers (13.9±1.2 years) and nine collegiate baseball pitchers (20.1± 0.8 years) were selected as subjects. All of them were classified as over-hand style pitchers. The baseball was filmed immediately after the ball release using a high-speed video camera (250 Hz). The direction of spin axis and the spin rate were calculated using positional changes of drawn marks on the ball surface. The direction of the spin axis was defined by two angles, θ(azimuth) and φ(elevation). The angle between spin axis and pitching direction (α) was also obtained (Jinji and Sakurai 2006). Mean values of the angles of the spin axis showed no significant differences between youth pitchers and collegiate pitchers. As for variations within each trial, however, youth pitchers were significantly more inconsistent than collegiate pitchers. Although youth pitchers have acquired similar pitching motion to adults on average, their motion was often unstable with large variations. There was a significant difference in the mean values of spin rate between the youth pitchers and collegiate pitchers (p<0.001). Moreover, the spin rate correlated significantly with the initial ball velocity (p<0.001). Pitchers with a higher initial velocity achieved a notably higher spin rate. It was concluded that a pitching motion that increased the ball velocity consequently increased spin rate.

著者

森下 義隆 勝亦 陽一 神事 努

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.2, pp.463-474, 2019-12-16 (Released:2019-12-20)

参考文献数

21

被引用文献数

2

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The purpose of the present study was to clarify the influence of swing parameters by changing the hitting point in space in baseball batting. Twenty-eight skilled baseball players (12 professional and 16 universitylevel) participated. The participants were instructed to hit a ball that was tossed from 5 m away in the direction of the pitching mound. The balls were tossed to various locations with reference to the home plate. The participants were required to hit the balls in a specific direction according to the tossed course, i.e., a ball tossed to the inside of a home plate was stroked toward the same-field direction and one tossed outside of the home plate was stroked toward the opposite-field direction. The motions of the ball and bat during these attempts were recorded using a motion capture system operating at 500 Hz. The 3D coordinates of the ball center (hitting point) and the swing parameters included the speed of the head of the bat (bat-head speed) and the angle of the swing from a horizontal line (swing angle) measured immediately before ball impact and the time from the start of the swing to ball impact (swing time). These parameters were calculated in each trial. Analysis of a total of 644 trials revealed that the bathead speed tended to increase as the hitting point moved inside, forward, and low. Furthermore, the swing angle and swing time tended to increase as the hitting point moved inside, forward, and high. Stepwise multiple regression analysis demonstrated that the bat-head speed and swing angle were independently associated with (in the following order) the distance in the pitcher’s direction, the hitting height, and the inside-outside direction course (R2=.360 and R2=.589, respectively). These results suggest that the timing of swing initiation and bat acceleration during a swing motion are the main factors changing the swing parameters, and that in order to sharp hit a ball, it is important to impact the ball with the hitting point as close to the pitcher as possible.

著者

森下 義隆 勝亦 陽一 神事 努

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.18058, (Released:2019-07-05)

参考文献数

21

被引用文献数

2

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The purpose of the present study was to clarify the influence of swing parameters by changing the hitting point in space in baseball batting. Twenty-eight skilled baseball players (12 professional and 16 universitylevel) participated. The participants were instructed to hit a ball that was tossed from 5 m away in the direction of the pitching mound. The balls were tossed to various locations with reference to the home plate. The participants were required to hit the balls in a specific direction according to the tossed course, i.e., a ball tossed to the inside of a home plate was stroked toward the same-field direction and one tossed outside of the home plate was stroked toward the opposite-field direction. The motions of the ball and bat during these attempts were recorded using a motion capture system operating at 500 Hz. The 3D coordinates of the ball center (hitting point) and the swing parameters included the speed of the head of the bat (bat-head speed) and the angle of the swing from a horizontal line (swing angle) measured immediately before ball impact and the time from the start of the swing to ball impact (swing time). These parameters were calculated in each trial. Analysis of a total of 644 trials revealed that the bathead speed tended to increase as the hitting point moved inside, forward, and low. Furthermore, the swing angle and swing time tended to increase as the hitting point moved inside, forward, and high. Stepwise multiple regression analysis demonstrated that the bat-head speed and swing angle were independently associated with (in the following order) the distance in the pitcher’s direction, the hitting height, and the inside-outside direction course (R2=.360 and R2=.589, respectively). These results suggest that the timing of swing initiation and bat acceleration during a swing motion are the main factors changing the swing parameters, and that in order to sharp hit a ball, it is important to impact the ball with the hitting point as close to the pitcher as possible.

著者

神事 努

出版者

國學院大學

雑誌

基盤研究(C)

巻号頁・発行日

2015-04-01

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セイバーメトリクス(野球選手評価数理理論)と呼ばれる統計量によって、野球の投手の能力を評価することが一般的になりつつある。野球規則の1.05にもあるように、野球の試合の目的は相手より多くの得点を上げて勝つことである。このことから、攻撃はどうやって得点を奪い、守備は失点を防ぐのかという観点がセイバーメトリクスの原点になっている。投手に関して言えば、3アウトを生み出すまでにできるだけ得点を与えないほうが良い。よって、ほぼ100%アウトになる奪三振が多い投手は評価が高くなる。また、フライよりもゴロを打たせたほうがアウトになりやすく、長打になりにくいことがわかってきている。これら統計量は、投手の能力を総合的に評価できる一方で、投球されたボールやフォームに関する力学量とどのように関連しているのか明らかになっていない。そこで、セイバーメトリクスで扱う統計量が、投球されたボールの速度や回転、フォームなどのバイオメカニクス的変量とどのような関係があるのかを検証することを本研究の目的とした。本研究では、試合中のボールの初速度、回転速度、リリース位置、投球軌跡等を自動で計測できるシステム(TrackMan Baseball、以下Trackman)によって取得されたデータと、セイバーメトリクスとの関連性を検証している。しかしながら、このシステムで取得できるデータには、いくつかの項目において系統誤差が含まれていることが明らかになった。また、球種のタグ付けに関しては、人が判定しており、球種判定の妥当性が低いことが明らかになった。系統誤差の補正や、球種判定の自動化のようなデータのクレンジング作業をこれまで行ってきた。また、これら作業に影響を受けない部分のデータを用いて、打球の傾向(打球飛距離、打球速度、打球角度)と投球されたボールの到達地点の関連性を調べ、日本野球科学研究会にて発表を行った。

著者

神事 努 桜井 伸二

出版者

一般社団法人 日本体育学会

雑誌

日本体育学会大会号 第55回(2004) (ISSN:24330183)

巻号頁・発行日

pp.338, 2004-09-01 (Released:2017-08-25)