17 Nov. 2020
34, 784, 789, 01 May 2012, Jinji, T., Ohta, K., Ozaki, H.
34, 218, 223, 01 May 2012, Ozaki, H., Ohta, K., Jinji, T.
26 (5), 1281, 1295, 01 May 2012, Ikeda, Y., Jinji, T., Matsubayashi, T., Matsuo, A., Inagaki, E., Takemata, T., and Kikuta, M.
16, 41, 46, 01 Jan. 2012, 神事努, 森下義隆, 平山大作, 平野裕一
16, 52, 59, 01 Jan. 2012, 森下 義隆 , 那須 大毅, 神事努, 平野裕一
16, 14, 21, 01 Jan. 2012, 平山大作, 島田一志, 川村卓, 松尾知之, 神事努, 平野裕一
459, 464, 01 Oct. 2011, 神事努, 太田憲, 尾崎宏樹
453, 458, 01 Oct. 2011, 尾崎宏樹, 太田憲, 神事努
01 Sep. 2011
29 (7), 761, 767, 01 Apr. 2011, Jinji, T., Sakurai,.S and Hirano, Y.
01 Aug. 2010, Jinji, T., Sakurai,.S and Hirano, Y.
12, 262, 267, 01 Feb. 2009, 神事努, 桜井伸二
30, 19, 32, 01 Dec. 2008, 神事努, 桜井伸二
323, 326, 01 Jun. 2008, Jinji, T., Sakurai, S.
11, 276, 288, 01 Feb. 2008, 近田彰治, 神事努, 矢内利政, 桜井伸二, 清水卓也
49(1), 21, 27, 01 Jan. 2008, 神事努, 桜井伸二, 清水卓也, 鈴木康博
29, 1, 16, 01 Dec. 2007, 桜井伸二, 神事努, 笹川慶, 塚田卓巳, 山崎剛盛
vol.5 (2), 197, 214, 01 Jul. 2006, Jinji, T., Sakurai,.S.
323, 326, 01 Jun. 2006, Jinji, T., Sakurai, S.
3 (2), 80, 84, 01 Jul. 2005, 神事努, 桜井伸二
1(5), 320, 325, 01 Dec. 2003, 神事努, 桜井伸二
43 (1), 23, 29, 01 Mar. 2001, 神事努, 望月知徳, 湯浅景元
43 (1), 31, 38, 01 Mar. 2001, 望月知徳, 神事努, 湯浅景元
30, 01 Mar. 2015, 大西基也, 神事努,真鍋芳明, 百武憲一, 森 実由樹, 櫻井健一
vol.15 (2), 220, 233, 01 Apr. 2016
17, (2), 180, 191, 17 Jan. 2018, Matsuo, T., Jinji, T., Hirayama, D., Nasu, D., Ozaki, H., & Kumagawa, D.
;;;;;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 66, 0, 2015, Japan Society of Physical Education, Health and Sport Sciences
Optimization for pitching and batting motion in professional baseball players, JINJI Tsutomu;MORIMOTO Ryota;KINOSHITA Hiroshi;NAKAO Shinichi, The Proceedings of Mechanical Engineering Congress, Japan, 2017, 0, 2017, The Japan Society of Mechanical Engineers
Development of pitching analysis system using baseball-type sensor, SHIBATA Shohei;NARUO Takeshi;KASE Yuto;YAMAMOTO Michiharu;MORI Masaki;URAKAWA Kazuo;HIROSE Kiyoshi;JINJI Tsutomu, The Proceedings of the Symposium on sports and human dynamics, 2017, 0, B, 3, 2017, The Japan Society of Mechanical Engineers,
The purpose of this study is to develop the system analyzing pitching data using baseball-type sensor and to examine the accuracy of the developed system using Doppler radar system (Trackman baseball, Trackman) and high speed camera. The developed baseball-type sensor in this study, which consists of accelerometer, gyroscope, and Magneto-Impedance sensor, measured 6-axis acceleration, 3-axis angular velocity, and 3-axis magnetic field. The weight, moment of inertia, and material in baseball-type sensor was the same as a normal baseball. The spin rate of pitched ball was calculated from data of 3-axis magnetic field using zero crossing method. The spin axis of pitched ball was calculated from data of 12-axis sensor using the sensor fusion by extended Kalman Filter. The measurement experiment was conducted to indicate the accuracy of the developed system. The spin rate calculated by the proposed method was corresponded with the spin rate obtained by the Doppler radar system (r = 0.99, R2 = 0.99). Also, it was indicated that the developed system could measure the low spin rate (less than 8.3 rps) which Doppler radar system could not measure. In overthrow data, it was indicated that the spin axis calculated by the proposed method was corresponded with the spin axis obtained by the Doppler radar system. From these result, the developed system can be used to evaluate baseball pitching skill with high accuracy.
;;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 65, 0, 2014, Japan Society of Physical Education, Health and Sport Sciences
;;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 65, 0, 2014, Japan Society of Physical Education, Health and Sport Sciences
C3 Mathematical analysis of the baseball pitching model based on a double pendulum, JINJI Tsutomu;OHTA Ken;OZAKI Hiroki, The Proceedings of the Symposium on sports and human dynamics, 2011, 0, 459, 464, 2011, The Japan Society of Mechanical Engineers, Some studies have reported that movements of forearm and wrist has several rolls to perform a baseball pitching. However dynamical mechanism of the forearm and the wrist are still unclear. As a step toward understanding the rolls of forearm and hand in baseball pitching, we investigated how non-muscular (e.g. centrifugal. Coriolis, and gravity) forces of the each link generates, absorbs, and transfers mechanical energy in order to produce maximum velocity. This was accomplished using multi-body power analysis derived entirely from dynamical equations of a 3D double pendulum with moving pivot model. In order to analyze based on this model, collegiate male baseball pitchier arm movements were captured by motion capture system with IkHz sampling. The analysis clarified that mechanical energy of the hand segment was transferred through internal force which was mainly dominated by centrifugal force, although muscle torque applied to the wrist joint absorbed the mechanical energy of the hand segment rather than increasing the energy.
C2 Mathematical analysis of kicking motion based on a double pendulum, OZAKI Hiroki;OHTA Ken;JINJI Tsutomu, The Proceedings of the Symposium on sports and human dynamics, 2011, 0, 453, 458, 2011, The Japan Society of Mechanical Engineers, In order to kick a ball of maximum velocity, swing linear velocity at impact phase must be maximum. The aim of this study was to clarify mechanism of produce maximum velocity of the foot using mathematical analysis based on a three-dimensional double pendulum with moving pivot model. We investigated how non-muscular forces of each link generates, absorbs and transfers the energy in order to produce the maximum swing velocity of the leg.
;;;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 62, 0, 2011, Japan Society of Physical Education, Health and Sport Sciences
235 Development of the pitching simulation system for the high-speed ball and the prevention against injury, ISHII Takeo;MATSUO Tomoyuki;JINJI Tsutomu;HIRAYAMA Daisaku;AOKI Kei;MIYAKAWA Shumpei, The Proceedings of the Symposium on sports and human dynamics, 2012, 0, 354, 359, 2012, The Japan Society of Mechanical Engineers, The purpose of this study is to develop the new system that can predict both the ball-speed and the throwing shoulder injury easily and can simulate pitching motion for the high-speed ball and the prevention against injury efficiently. The subjects were asymptomatic 11 adult baseball players who took part in both MRI and pitching motion analysis, (total 358 trials) We made the database composed of the data of joint angles, findings of MRI and ball-speed. We analyzed the database with principal component analysis and classified the motion patterns into the principal component scores. Then we made the simulation system using principal component score and optimization theory. We could predict the lesion existence and ball-speed with high accuracy. We can make the new pitching motion easily while we operate the parameters of principal component scores referring to the prediction value. We can express the new motion with 3D animations.
;;;;;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 66, 0, 2015, Japan Society of Physical Education, Health and Sport Sciences
Characteristics of ball spin pitched by baseball pitchers in the period of development, JINJI T;;;;Tsutomu JINJI;Shinji SAKURAI;Takuya SHIMIZU;Yasuhiro SUZUKI, Research journal of health and sport sciences, Chukyo University, 49, 1, 21, 27, 2008, 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.
Activity Report 2017 of Community Health Promotion Center in Kokugakuin University, ;;;;;;;;, 10, 151, 158, Feb. 2019
symposium report, ;;;, 9, 41, 46, Feb. 2018
Biomechanics and ICT Utilization in Physical Education, 9, 32, 35, Feb. 2018
Medical assessment on shoulder and elbow joints of juvenile players of baseball club in Aichi Prefecture, ;;;;;Takuya SHIMIZU;Yasuhiro SUZUKI;Shouji KONDA;Tsutomu JINJI;Shinji SAKURAI, Research journal of health and sport sciences, Chukyo University, 48, 1, 1, 6, 2007, The purposes of this study are to clarify when and which characteristics that have been supposed to be the cause of "baseball shoulders" such as instability, subacromial impingement and SLAP lesions observed in adults develop them. We had medical check of forty juvenile baseball players (av.12.3 years). They belong to the same baseball club in Aichi prefecture. One senior sports doctor measured range of motion and examine tenderness points, sings and laxities of the bilateral shoulder and elbow joints. External rotation of the first position of the dominant side was significantly greater than that of the non-dominant side. External rotation of the third position of the dominant side was significantly greater than that of the non-dominant side and internal rotation of the third position of the dominant side was significantly less than that of the non-dominant side. There ware little pathological signs in shoulder and elbow joints of these juvenile baseball players. One player showed positive anterior load and shift test of the shoulder of dominant side and six showed those of non-dominant side. Seven players showed positive posterior load and shift test of the shoulders of dominant side and fifteen showed those of non-dominant side. Five players showed positive sulcus signs of the shoulders of dominant side and eight showed those of non-dominant side. The nine players who had positive sulcus signs on either dominant or non-dominant side had significantly less internal rotation of the third position than the other players. Whereas the eighteen players who had positive posterior laxity on either dominant or non-dominant side didn't have significantly less internal rotation of the third position than the other players. Positive sulcus sign suggests inferior laxity. This means inferior laxity has different role on developing posterior tightness of the throwing shoulder from posterior laxity.
;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 58, 0, 2007, Japan Society of Physical Education, Health and Sport Sciences
;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 56, 0, 2005, Japan Society of Physical Education, Health and Sport Sciences
;, Abstracts of Japan Society of Physical Education, Health and Sport Sciences Conference, 55, 0, 2004, Japan Society of Physical Education, Health and Sport Sciences
symposium report, ;;, 9, 18, 23, Feb. 2018
Relation between the Supporting Leg and the Velocity of the Ball by Instep Kick and the Fundamental Part of Supporting Leg, ;;;Tomonori MOCHIZUKI;Tsutomu JINJI;Kagemoto YUASA, Research journal of physical education,Chukyo University, 43, 1, 31, 38, 2001, The purpose of this study is to investigate the relation between the joint angle and horizontal velocity of the supporting leg and the velocity of the ball by an instep kick as powerful as possible. Subjects were 3 male students who were skilled members of the college soccer club and 3 male non-skilled persons. In this study, the velocity of the ball, foot, greater trochanters and knee and angle of the knee were analyzed three-dimensionally (3-D). The results were as follows : (1) A significant correlation (r=0.903) was found between the velocity of the ball and the velocity of the foot. (2) Skilled persons kicked the ball using good waist rotation. This rotation is a factor which increases the velocity of the ball. (3) Skilled persons fixed the supporting leg, the angle of the knee was about 150 degrees and the velocity of the knee was lower than in non-skilled persons.
How the Stepping Leg's Motion is Related to the Initial Velocity, While Practice pitching, ;;;Tsutomu JINJI;Tomonori MOCHIZUKI;Kagemoto YUASA, Research journal of physical education,Chukyo University, 43, 1, 23, 29, 2001, This study deals with how stepping leg and waist motion are related to initial velocity, while practicing baseball pitching. Six pitchers belonging to the university baseball team did the actual pitching for this study and were filmed using the direct linear transformation method of three-dimensional (3D) videography. Several factors determine the initial velocity. Toyoshima^<4)> mentions that the sharp rotation of the waist is one of the big factors. Moreover, the importance of the lower limbs is frequently mentioned on the actual coaching scene. The results of this study are mentioned below. 1. The waist changes its motion from advance to rotating 0.1 sec before the foot lands on the ground, and the right trochanter major speeds up by slowing down the left trochanter major while the waist rotates sharply. 2. It is possible to speed up the waist angular velocity by fixing the joints of the knee and the legs when the foot is landing.
Activity Report 2018 of Community Health Promotion Center in Kokugakuin University, ;;;;;;;;, 11, 147, 158, Feb. 2020
A study on the pitching data analysis and useage using baseball-type sensor, SHIBATA Shohei;NARUO Takeshi;KASE Yuto;INAMO Masaya;YAMAMOTO Michiharu;MORI Masaki;URAKAWA Kazuo;HIROSE Kiyoshi;JINJI Tsutomu, The Proceedings of the Symposium on sports and human dynamics, 2018, 0, A, 18, 2018, The Japan Society of Mechanical Engineers,
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.
The effect of changes in hitting location on bat-swing parameters in baseball batting, Morishita Yoshitaka;Katsumata Yoichi;Jinji Tsutomu, Taiikugaku kenkyu (Japan Journal of Physical Education, Health and Sport Sciences), 64, 2, 463, 474, 16 Dec. 2019, Japan Society of Physical Education, Health and Sport Sciences, 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.
;, 1, 5, 320, 325, 2003
;, 3, 2, 80, 84, 2005
Flight trajectory, direction of spin axis and spin rate of sports ball, ;;, Tokai annual report of health and physical education, 29, 1, 16, 2007
A method for estimating three-dimensional scapular rotation with the use of optical motion capture system during humeral elevation, ;;, Japanese journal of biomechanics in sports & exercise, 11, 4, 276, 288, 2007
Dynamics of the forearm and wrist joints of the throwing arm around ball release in overhand throwing, ;, Tokai annual report of health and physical education, 30, 19, 32, 2008
;, Japanese journal of biomechanics in sports & exercise, 12, 4, 267, 277, 2008
;;, 16, 1, 41, 46, 2012
;;, 16, 1, 52, 59, 2012
Scientific Support for Top Athletes, 27, 137, 149, 2013
A study of neck movement during a head-first slide in baseball, ;;, 30, 13, 19, 2014
Direction of spin axis and spin rate in professional baseball pitchers, ;;, 30, 130, 132, 2014
The influence that the Ultra light hurdle gives for hurdling technique, ;;, 31, 130, 132, 2015
;;;, 9, 41, 46, Feb. 2018
17, 2, 108, 112, 01 Aug. 2019
32, 13, 12, 15, Jul. 2018
51, 3, 20, 27, Mar. 2020
Activity Report 2019 of Community Health Promotion Center in Kokugakuin University, ;;;;;;, 12, 73, 81, 01 Feb. 2021
;;;;;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 66, 0, 2015, Japan Society of Physical Education, Health and Sport Sciences
;;;;;, Japan Society of Physical Education, Health and Sport Sciences Conference Proceedings, 66, 0, 193, 2015, Japan Society of Physical Education, Health and Sport Sciences
A study on the pitching data analysis and useage using baseball-type sensor, SHIBATA Shohei;NARUO Takeshi;KASE Yuto;INAMO Masaya;YAMAMOTO Michiharu;MORI Masaki;URAKAWA Kazuo;HIROSE Kiyoshi;JINJI Tsutomu, The Proceedings of the Symposium on sports and human dynamics, 2018, 0, A-18, 2018, The Japan Society of Mechanical Engineers,
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.
Optimization for pitching and batting motion in professional baseball players, JINJI Tsutomu;MORIMOTO Ryota;KINOSHITA Hiroshi;NAKAO Shinichi, The Proceedings of Mechanical Engineering Congress, Japan, 2017, 0, F123003, 2017, The Japan Society of Mechanical Engineers
The effect of changes in hitting location on bat-swing parameters in baseball batting, Morishita Yoshitaka;Katsumata Yoichi;Jinji Tsutomu, Taiikugaku kenkyu (Japan Journal of Physical Education, Health and Sport Sciences), 64, 2, 463, 474, 16 Dec. 2019, Japan Society of Physical Education, Health and Sport Sciences, 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.
Development of pitching analysis system using baseball-type sensor, SHIBATA Shohei;NARUO Takeshi;KASE Yuto;YAMAMOTO Michiharu;MORI Masaki;URAKAWA Kazuo;HIROSE Kiyoshi;JINJI Tsutomu, The Proceedings of the Symposium on sports and human dynamics, 2017, 0, B-3, 2017, The Japan Society of Mechanical Engineers,
The purpose of this study is to develop the system analyzing pitching data using baseball-type sensor and to examine the accuracy of the developed system using Doppler radar system (Trackman baseball, Trackman) and high speed camera. The developed baseball-type sensor in this study, which consists of accelerometer, gyroscope, and Magneto-Impedance sensor, measured 6-axis acceleration, 3-axis angular velocity, and 3-axis magnetic field. The weight, moment of inertia, and material in baseball-type sensor was the same as a normal baseball. The spin rate of pitched ball was calculated from data of 3-axis magnetic field using zero crossing method. The spin axis of pitched ball was calculated from data of 12-axis sensor using the sensor fusion by extended Kalman Filter. The measurement experiment was conducted to indicate the accuracy of the developed system. The spin rate calculated by the proposed method was corresponded with the spin rate obtained by the Doppler radar system (r = 0.99, R2 = 0.99). Also, it was indicated that the developed system could measure the low spin rate (less than 8.3 rps) which Doppler radar system could not measure. In overthrow data, it was indicated that the spin axis calculated by the proposed method was corresponded with the spin axis obtained by the Doppler radar system. From these result, the developed system can be used to evaluate baseball pitching skill with high accuracy.