著者

梅垣 浩二 室伏 広治 桜井 伸二 高松 潤二

出版者

一般社団法人 日本体育学会

雑誌

日本体育学会大会予稿集

巻号頁・発行日

vol.56, 2005

著者

梅垣 浩二 室伏 広治 桜井 伸二

出版者

一般社団法人 日本体育学会

雑誌

日本体育学会大会予稿集

巻号頁・発行日

vol.61, 2010

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

桜井 伸二 池上 康男 矢部 京之助 岡本 敦 豊島 進太郎

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.35, no.2, pp.143-156, 1990-09-01 (Released:2017-09-27)

被引用文献数

10 6

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Many joint actions are involved in the throwing motion of a fastball pitch; therefore, two dimensional (2-D) procedures are insufficient for analyzing the throwing motion. In this study,three dimensional (3-D) high-speed cinematography was used to record fastball pitches of varsity baseball pitchers. Two small reference sticks were fixed on the hands and forearms of the throwing arm of the subjects to detect their movements.The direct linear transformation (DLT) method was used for 3-D space reconstruction from 2-D images filmed by two from 2-D images filmed by two phase-locked cameras (200 frames/s).The throwing arm has seven degrees of freedom of joint motion except in the fingers; three for the shoulder, one for the elbow, one for the radioulnar, and two for the wrist. Following seven joint angle changes corresponding to all these degrees of freedom were obtained throughout the pitching motion. 1) horizontal abduction/horizontal adduction angle at the shoulder joint, 2) abduction/adduction angle at the shoulder joint, 3) internal rotation/external rotation angle at the shoulder joint, 4) flexion/extension angle at the elbow joint, 5) pronation/supination angle at the radio-ulnar joint (forearm), 6) radial flexion/ulnar flexion angle at the wrist joint, 7) palmar flexion/dorsi flexion angle at the wrist joint. The results showed that horizontal adduction and internal rotation of the shoulder,extension of the elbow, pronation of the forearm, and palmar flexion of the wrist were the important joint actions for fastball pitching in baseball. Preliminary to these motions were motions in the opposite direction; e.g., horizontal abduction and external rotation of the shoulder,flexion of the elbow, supination of the forearm, and dorsi flexion of the wrist were detected.These motions in the opposite direction would be useful to extend the range of the motion in each joint angle. The results also appear to be connected to intrinsic muscle propertios, that greater power can be exerted during shortening of the muscle when it is stretched just before the shortening action.

著者

中島 大貴 塚元 佑真 樗澤 寧々 井上 沙美 桜井 伸二

雑誌

中京大学体育研究所紀要 = BULLETIN OF RESEARCH INSTITUTE OF HEALTH AND SPORT SCIENCES CHUKYO UNIVERSITY

巻号頁・発行日

vol.34, pp.71-75, 2020-03-31

著者

豊嶋 陵司 桜井 伸二

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.17126, (Released:2019-02-26)

参考文献数

19

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In sprint running, stance time and flight time influence running speed. This study investigated the relationship between flight ratio (= flight time/stance time) and the upper limbs and recovery leg during the top speed phase in sprinting. Sixteen male sprinters (age 19.3±0.6 y, height 1.74±0.06 m, weight 66.1±5.2 kg) performed maximum-effort 60-m sprints. Video data from the 43.5 to 50 m section of the sprint were collected using a high-speed camera (300 Hz). Flight ratio and vertical acceleration force of the upper limbs relative to the sternum and recovery leg relative to the hip were calculated. The data revealed a significant positive correlation between flight ratio and the relative vertical acceleration force of the forward arm, backward arm, and recovery leg at the instant of touchdown (r =.597, .546, .592). The maximum value of the relative vertical acceleration force of the forward arm, backward arm, and recovery leg during the stance phase was not associated with the flight ratio. In contrast, early appearance of the maximum value of the vertical relative acceleration force of the forward arm, backward arm, and recovery leg during the stance phase was associated with a high flight ratio (r = -.553, -.644, -.855). Multiple regression analysis revealed that the high angular velocity and low extension acceleration of the arms and recovery leg at touchdown made a significant contribution to high relative vertical acceleration. In conclusion, rapid swinging and high shortening acceleration of the arms and recovery leg can contribute to a high flight ratio by facilitating a high relative vertical acceleration force.

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)

著者

豊嶋 陵司 田内 健二 遠藤 俊典 礒 繁雄 桜井 伸二

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

vol.60, no.1, pp.197-208, 2015 (Released:2015-06-13)

参考文献数

27

被引用文献数

5 3

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The purpose of this study was to clarify the biomechanical factors that influence intra-individual variations in step frequency (SF) and length (SL) during sprint running. One male sprinter participated as a study subject, and performed a 60-m sprint at maximal effort. Experiments were conducted 5 times, with a total number of 14 trials. The ground reaction force and positions of markers attached to the joints were recorded using force plates and a motion capture system. Trials were divided into SF type and SL type depending on the SF/SL ratio, and the kinematic variables and ground reaction force were compared. The main results were as follows.   1)  There were no significant differences in sprint velocity and stance time between the SF type and the SL type.   2)  The flight time of the SL type was longer than that of the SF type.   3)  Vertical components of the ground reaction force and impulse during the stance phase were larger for the SL type than for the SF type.   4)  The thigh angle of the swing leg was larger for the SL type than for the SF type during almost all phases.   5)  The hip joint of the swing leg was flexed to a greater degree during the stance phase and first half of the flight phase for the SL type than for the SF type.   6)  There were no marked differences in the segment and joint angular velocities between the SF type and the SL type.   These results indicate that changes in step frequency and step length with flight time are due to an increase or decrease of vertical impulse. Moreover, it was revealed that vertical impulse is influenced by the thigh angle of the swing leg during the stance phase, rather than by the angular velocity of the swing leg.

著者

安 栽漢 桜井 伸二 金 興烈

出版者

一般社団法人日本体力医学会

雑誌

体力科学 (ISSN:0039906X)

巻号頁・発行日

vol.56, no.1, pp.167-178, 2007-02-01 (Released:2007-05-15)

参考文献数

26

被引用文献数

1 2

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The purpose of this study was to compare muscle activity of the lower limb during treadmill running under five different gradient conditions (level, left and right inclines, downward and upward). All inclines were of 14% grade and tilted toward the left, the right, downward and upward directions of the runner. Twelve young healthy males ran at 2.8 m/s. Electromyographic activities of the following seven muscles-gluteus maximus, biceps femoris, rectus femoris, vastus lateralis, tibialis anterior, medial gastrocnemius, and solues-were measured using bipolar surface electrodes during treadmill running under five different conditions. Results showed that left and right inclined surfaces had only little influence on muscular activity. However, for all of the muscles measured, the activity of the lower-positioned leg was greater than that of the higher-positioned leg. During the upward incline trial, all the muscles showed greater activity than for the other trials. The downward slope tended to give the anterior muscles greater activity, and the posterior muscles less activity, compared to level running.

著者

堀内 元 桜井 伸二

出版者

一般社団法人 日本体育学会

雑誌

日本体育学会大会予稿集 第68回(2017) (ISSN:24241946)

巻号頁・発行日

pp.147_1, 2017 (Released:2018-02-15)

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野球のバッティング動作では、左右の股関節が力学的エネルギーの主な発生源であることが示唆されている。そこで、本研究の目的は、股関節で発生する力学的エネルギーに関連する動作および力の発揮について検討することであった。男子アマチュア野球選手98名のバッティング動作を記録し、バットヘッドスピードと股関節角度および股関節で生成された力学的エネルギーの相関係数を算出した。その結果、いずれの時点での股関節角度においても、バットヘッドスピードとの間に有意な相関関係は認められなかった。また、捕手側の股関節では伸展トルクによる力学的エネルギーの発生がほとんどで、バットヘッドスピードと有意な相関関係が認められた。加えて、投手側の股関節では屈曲トルクおよび内転トルクによって発生した力学的エネルギーの割合が大きかった。これらのことから、野球のバッティング動作では、バットヘッドスピードの大きさによって股関節角度に差異はなく、左右の股関節の非対称な力の発揮によって力学的エネルギーが生成されていることが明らかになった。加えて、捕手側の股関節における伸展トルクの発揮能力がバットヘッドスピードに関連することが示唆された。

著者

宮西 智久 桜井 伸二

出版者

社団法人日本体育学会

雑誌

日本体育学会大会号

巻号頁・発行日

no.50, 1999-09-15

著者

尾関 一将 水藤 弘吏 桜井 伸二 浦田 達也

出版者

大阪体育大学

雑誌

若手研究(B)

巻号頁・発行日

2013-04-01

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競泳スタート時におけるスタート台に作用する力を手部,足部それぞれ独立して測定し,評価する方法を確立することができた.大学生以上の男子および女子競泳選手において新しいスタート台を用いたキックスタートを用いることの優位性が明らかとなった.また,女子一流競泳短距離選手のキックスタートの特徴として,高い跳び出し水平速度の獲得よりもブロックタイムを短縮するためにスタート姿勢の身体重心位置を前方向にして構えていることを報告した.これらのスタート開始時の構えにおいて,スタート構え時の前方向の脚における等尺性最大脚筋力が大きいほど,跳び出し水平速度が高く,5m通過時間が有意に短かったことが明らかとなった.

著者

桜井 伸二 池上 康男 矢部 京之助 岡本 敦 豊島 進太郎

出版者

社団法人日本体育学会

雑誌

体育學研究 (ISSN:04846710)

巻号頁・発行日

vol.35, no.2, pp.143-156, 1990-09-01

被引用文献数

8

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Many joint actions are involved in the throwing motion of a fastball pitch; therefore, two dimensional (2-D) procedures are insufficient for analyzing the throwing motion. In this study,three dimensional (3-D) high-speed cinematography was used to record fastball pitches of varsity baseball pitchers. Two small reference sticks were fixed on the hands and forearms of the throwing arm of the subjects to detect their movements.The direct linear transformation (DLT) method was used for 3-D space reconstruction from 2-D images filmed by two from 2-D images filmed by two phase-locked cameras (200 frames/s).The throwing arm has seven degrees of freedom of joint motion except in the fingers; three for the shoulder, one for the elbow, one for the radioulnar, and two for the wrist. Following seven joint angle changes corresponding to all these degrees of freedom were obtained throughout the pitching motion. 1) horizontal abduction/horizontal adduction angle at the shoulder joint, 2) abduction/adduction angle at the shoulder joint, 3) internal rotation/external rotation angle at the shoulder joint, 4) flexion/extension angle at the elbow joint, 5) pronation/supination angle at the radio-ulnar joint (forearm), 6) radial flexion/ulnar flexion angle at the wrist joint, 7) palmar flexion/dorsi flexion angle at the wrist joint. The results showed that horizontal adduction and internal rotation of the shoulder,extension of the elbow, pronation of the forearm, and palmar flexion of the wrist were the important joint actions for fastball pitching in baseball. Preliminary to these motions were motions in the opposite direction; e.g., horizontal abduction and external rotation of the shoulder,flexion of the elbow, supination of the forearm, and dorsi flexion of the wrist were detected.These motions in the opposite direction would be useful to extend the range of the motion in each joint angle. The results also appear to be connected to intrinsic muscle propertios, that greater power can be exerted during shortening of the muscle when it is stretched just before the shortening action.