著者

蔭山 雅洋 鈴木 智晴 藤井 雅文 中本 浩揮 和田 智仁 前田 明

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.61, no.2, pp.517-535, 2016 (Released:2016-12-14)

参考文献数

37

被引用文献数

2 5

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The purpose of this study was to clarify the profiles of lower limb and trunk motion during baseball pitching in relation to differences between the mound and the flat ground, and to determine the motion characteristics while pitching from the 2 locations.  The subjects were 12 baseball pitchers (age 18.6±2.5 yr, height 173.4±6.5 cm, weight 74.7±11.0 kg) who belonged to high school or university baseball teams. Three-dimensional positions of 36 reflective markers attached to each subject were tracked by an optical motion capture system (Mac3D System) with 12 cameras. The ground-reaction forces (GRF) of the pivot and stride legs during pitching were determined using 2 multicomponent force plates. Pitching motion was divided into two phases: phase 1 was defined as the period from when the knee of the stride leg reached maximal height (MKH: 0%time) until the point when the stride foot made contact with the ground (SFC: 100%time), while phase 2 was defined as the period from the SFC until the point when the ball was released (REL: 200%time). Ball velocity was measured using a radar gun.  The results were as follows: 1) The maximum and average ball velocities were significantly higher when pitching was performed from the mound than from the flat ground (p<0.05). 2) Hip/knee flexion angles and hip abduction/extension angular velocities on the pivot leg were significantly greater for mound pitching than for flat ground pitching, and the hip/knee extension angle and hip adduction/internal rotation/flexion angular velocities on the stride leg were significantly greater for the former (p<0.05). 3) The GRF of the stride leg was significantly greater for mound pitching than for flat ground pitching (p<0.01). 4) Upper torso and pelvis angle/angular velocities at SFC and the maximum pelvis, upper torso and trunk tilt angular velocities were significantly greater for mound pitching than for flat ground pitching (p<0.05).  The present results indicate that baseball pitchers show biomechanical differences in the kinematic and kinetic profiles of the trunk and lower limbs when pitching from the mound in comparison with the flat ground, and that high school or collegiate baseball pitchers can increase their pitched ball velocity by using the height of the mound.

著者

鈴木 智晴 藤井 雅文 村上 光平 中本 浩揮 前田 明

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.64, no.1, pp.79-87, 2019-06-17 (Released:2019-06-25)

参考文献数

8

被引用文献数

2

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One of the important roles of a baseball catcher is to check whether an opponent is trying to steal a base. This checking action must occur as part of other events: a quick throwing action (short operation time), a high ball speed (short duration of ball flight), and accurate tagging (the time from the fielder catching the ball to touching the opponent runner is short). In other words, in order for the catcher to check whether an opponent is trying to steal a base, it is necessary to shorten the time between catching the ball and when the fielder touches the opponent runner. However, the relationship between the time and the possibility of checking for an attempt to steal a base and the influence of each phase on the steal check rate have not been examined. The present study investigated the relationship between the time required to prevent a steal and the steal check rate of a baseball catcher using video recordings. The video recordings used for our analysis were videos of steal check successes and failures in exhibition and official university and amateur baseball games, with a focus on runners attempting to steal second base. We classified Motion Time as the period from catching the initial pitch to ball release, Ball Time as the period from ball release to ball arrival at second base, and Touch Time as the period from ball arrival at second base to the fielder touching the runner; the sum of these 3 phases was defined as All Time, and the sum of Motion Time and Ball Time was defined as Pop Time. We constructed 3 models in which the success or failure of the steal check was set as a target variable and each phase time as an explanatory variable, and performed logistic regression analysis on each model. As a result, we clarified that the baseball catcher could check for a steal if the All Time was less than 2.429 s, and there was a significant negative correlation between the steal check rate and All Time. In addition, among the three phases, Touch Time had the greatest effect on the steal check rate. Therefore, it was suggested that accurate throwing is the most important factor in preventing a steal to second base.

著者

藤井 雅文

出版者

富山大学

雑誌

基盤研究(C)

巻号頁・発行日

2018-04-01

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本研究では、電磁気学および電子物理化学を基礎とする新しい原理による短期地震予測法を確立することを目標としている。地震の直前には地殻の岩盤に圧力が加わることにより、応力誘起された大量の電荷が岩石内部から放出される。そしてこれらが地表面に出現し滞留することで上空の電波によって励起されプラズマ振動する。これがさらに上空の電波伝搬に影響を与え、通常の状況では生じ得ない遠方への超長距離伝搬が引き起こされることが明らかになっている。特に地殻活動に伴う電磁気現象を理論と実験観測の両面から考察し、地震の前に地殻に作用する応力の変動を精密な電波観測により広範囲に検知し、その観測精度を向上することにより地震の短期予測を実現することを目指している。高感度低雑音の観測装置を用いて電磁波の観測を実施している。これまでに規模の大きな地震の数日前から前日にかけて、異常な電波伝搬現象を観測している。特に2022年3月16日の福島沖M7.4の地震の直前に非常に明瞭な電磁波異常を観測した。この観測結果により、これまでの異常現象が地殻活動に由来するものであることを示すことが可能となり、地震前兆時に異常信号が観測可能かどうかの論争に終止符を打てる可能性が高まっている。また、我々は地震予測の適中率と地震発生の予測率を評価しており、近年はそれぞれ90%近い値を得ている。さらに、観測データを深層学習により解析し異常信号から地震の発生を予測する研究を実施しており、高い精度で予測できる結果を得ている。これらの結果をすでにまとめて科学技術誌に投稿し、現在審査結果を待っている。

著者

山崎 浩二 髙橋 文子 伊東 晃 藤井 雅文 本宮 和奈 及川 光代 菊池 沙織 桐山 あかり 工藤 美波 佐々木 一向 佐藤 杏奈 白石 円 辻裕 美香 外舘 和雅 楢木 航平 沼川 卓也 宮崎 大地 稲垣 道子 川邊 智津瑠 工藤 真以 佐々木 愛香 清水 貴之 藤井 雅文 藤原 英文 渡辺 葵 加固 希支男

出版者

岩手大学教育学部

雑誌

教育実践研究論文集 (ISSN:24348422)

巻号頁・発行日

vol.7, pp.93-98, 2020-03

著者

蔭山 雅洋 大石 祥寛 亀田 麻依 藤井 雅文 北 哲也 前田 明

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.19102, (Released:2020-08-05)

著者

泊弘侑 幾留沙智 森司朗 鈴木智晴 蔭山雅洋 藤井雅文 前田明 中本浩揮

出版者

鹿屋体育大学

雑誌

スポーツパフォーマンス研究

巻号頁・発行日

vol.7, pp.228-237, 2015

著者

鈴木 智晴 藤井 雅文 村上 光平 中本 浩揮 前田 明

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

2019

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One of the important roles of a baseball catcher is to check whether an opponent is trying to steal a base. This checking action must occur as part of other events: a quick throwing action (short operation time), a high ball speed (short duration of ball flight), and accurate tagging (the time from the fielder catching the ball to touching the opponent runner is short). In other words, in order for the catcher to check whether an opponent is trying to steal a base, it is necessary to shorten the time between catching the ball and when the fielder touches the opponent runner. However, the relationship between the time and the possibility of checking for an attempt to steal a base and the influence of each phase on the steal check rate have not been examined. The present study investigated the relationship between the time required to prevent a steal and the steal check rate of a baseball catcher using video recordings. The video recordings used for our analysis were videos of steal check successes and failures in exhibition and official university and amateur baseball games, with a focus on runners attempting to steal second base. We classified Motion Time as the period from catching the initial pitch to ball release, Ball Time as the period from ball release to ball arrival at second base, and Touch Time as the period from ball arrival at second base to the fielder touching the runner; the sum of these 3 phases was defined as All Time, and the sum of Motion Time and Ball Time was defined as Pop Time. We constructed 3 models in which the success or failure of the steal check was set as a target variable and each phase time as an explanatory variable, and performed logistic regression analysis on each model. As a result, we clarified that the baseball catcher could check for a steal if the All Time was less than 2.429 s, and there was a significant negative correlation between the steal check rate and All Time. In addition, among the three phases, Touch Time had the greatest effect on the steal check rate. Therefore, it was suggested that accurate throwing is the most important factor in preventing a steal to second base.

著者

坂上 岩太 泉 圭輔 坂口 和志 藤井 雅文

出版者

一般社団法人電子情報通信学会

雑誌

電子情報通信学会技術研究報告. MW, マイクロ波 (ISSN:09135685)

巻号頁・発行日

vol.104, no.536, pp.7-12, 2004-12-13

被引用文献数

3

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90度の奇数培の位相差をもつ2ブランチ、3ブランチ集中定数3dBコダイレクショナル(COD)・ガップラを扱う。均等負荷の集中定数2ブランチCOD・カップラに関しては4通りの構成法が知られている。ここでは分布定数3dBブランチライン・カップラを出発点として、極めて容易にこの4通りの回路を導出する。次に、段数を1段増やした3ブランチCOD・カップラを取り扱う。従来はC7個、L6個よりなる回路、及びこれらの交換回路が知られている。2ブランチの場合と同様の手法により、新しくC9個、L4個の回路を示す。これにより4通りの2ブランチに対応した3ブランチ回路が得られる。また、帯域福の検討も行う。