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

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
阿江 数通 小池 関也 藤井 範久 阿江 通良 川村 卓 金堀 哲也
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.559-574, 2017 (Released:2017-12-19)
参考文献数
46

The purpose of this study was to compare the kinematic characteristics of the upper body between baseball tee batting and pitched ball batting in order to gain basic knowledge for improvement of batting skill. Ten male collegiate baseball players (age: 20.7±1.1 yr; height: 1.75±0.05 m; body mass: 76.3±7.1 kg; athletic career: 12.7±2.7 yr) participated. They performed 2 kinds of batting: tee batting (TB) and machine-pitch batting (MB) using a pitching machine (approximate ball speed 33.3 m/s), which were set at middle ball height for the strike zone. Three-dimensional coordinate data were acquired with a motion capture system. Kinematic variables such as maximum bat-head speed, swing time, bat angle, joint angles of the upper limbs, and segment angle of the upper trunk were calculated. Differences between TB and MB were analyzed statistically using paired t-test (p<0.05). The maximum bat-head speed was significantly greater in TB than in MB, but swing times divided into 2 phases showed no significant differences between MB and TB. In the first half of the swing, the bat inclination angle was significantly larger in MB than in TB. The joint angles of the barrel-side shoulder abduction, knob-side shoulder adduction and internal rotation were significantly larger in MB than in TB, and those of the barrel-side shoulder internal rotation and individual elbow pronations were significantly larger in TB than in MB. The clockwise rotational angle of the upper trunk was significantly larger in TB than in MB. In the last half of the swing, the joint angles of the barrel-side shoulder abduction, knob-side shoulder flexion and adduction were significantly larger in MB than in TB, and that of the knob-side elbow pronation was significantly larger in TB than in MB. The changes in upper body movement in MB affected the radius of rotation of the bat about the vertical axis to control the bat easily. The movements in the last half of the swing largely resulted from those in the first half of the swing, and did not contribute to timing adjustment. These results indicate that the initial configuration of the bat and upper limbs, and movements at the beginning of the bat swing contribute to the timing adjustment of the bat for a pitched ball. The results of the present study suggest that it could be useful to pay attention to the movement of the bat and upper body in the first half of the swing as TB practice in order to improve timing adjustment.
著者
阿江 数通 小池 関也 藤井 範久 阿江 通良 川村 卓 金堀 哲也
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
pp.16080, (Released:2017-09-01)
参考文献数
48

The purpose of this study was to compare the kinematic characteristics of the upper body between baseball tee batting and pitched ball batting in order to gain basic knowledge for improvement of batting skill. Ten male collegiate baseball players (age: 20.7±1.1 yr; height: 1.75±0.05 m; body mass: 76.3±7.1 kg; athletic career: 12.7±2.7 yr) participated. They performed two kinds of batting: tee batting (TB) and machine-pitch batting (MB) using a pitching machine (approximate ball speed 33.3 m/s), which were set at middle ball height for the strike zone. Three-dimensional coordinate data were acquired with a motion capture system. Kinematic variables such as maximum bat-head speed, swing time, bat angle, joint angles of the upper limbs, and segment angle of the upper trunk were calculated. Differences between TB and MB were analyzed statistically using paired t-test (p<0.05.) The maximum bat-head speed was significantly greater in TB than in MB, but swing times divided into two phases showed no significant differences between MB and TB. In the first half of the swing, the bat inclination angle was significantly larger in MB than in TB. The joint angles of the barrel-side shoulder abduction, knob-side shoulder adduction and internal rotation were significantly larger in MB than in TB, and those of the barrel-side shoulder internal rotation and individual elbow pronations were significantly larger in TB than in MB. The clockwise rotational angle of the upper trunk was significantly larger in TB than in MB. In the last half of the swing, the joint angles of the barrel-side shoulder abduction, knob-side shoulder flexion and adduction were significantly larger in MB than in TB, and that of the knob-side elbow pronation was significantly larger in TB than in MB. The changes in upper body movement in MB affected the radius of rotation of the bat about the vertical axis to control the bat easily. The movements in the last half of the swing largely resulted from those in the first half of the swing, and did not contribute to timing adjustment. These results indicate that the initial configuration of the bat and upper limbs, and movements at the beginning of the bat swing contribute to the timing adjustment of the bat for a pitched ball. The results of the present study suggest that it could be useful to pay attention to the movement of the bat and upper body in the first half of the swing as TB practice in order to improve timing adjustment.
著者
川村 卓 小池 関也 阿江 数通
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.1, pp.37-48, 2019-06-17 (Released:2019-06-25)
参考文献数
22

This study examined the flow of energy in the right and left upper limbs of skilled baseball batters during the forward swing motion at different bat head speeds to obtain basic insights that would be useful for batting coaching. The subjects were 23 college baseball outfielders in university teams. The subjects were instructed to hit a ball toward the pitcher from a tee set at a mid-height position. Measurements were taken using 47 points on each subject’s body and 6 points on the bat for a total of 53 points, onto which reflective markers were attached. The 3D coordinates of each marker were measured using a 3D optical motion capture device (Vicon Motion Systems’ VICONMX, 12 cameras, 250 Hz). The variables in the kinetics of each hand were measured using a force detection sensor bat (1000 Hz). The subjects were separated into a faster group of 36.8±0.8 m/s and a slower group of 34.7±1.1 m/s for analysis. In terms of energy transmission, the data revealed that the faster group, in addition to showing additional torque on the knob side shoulder joints, were able to transmit more mechanical energy from the knob side shoulder joints to the end of the upper limbs than the slower group, and that this might be related to an efficient bat head speed. In addition, the faster group showed an increased positive torque power, and transmitted greater mechanical energy to the bat from the hand region. In other words, to prevent mechanical energy from being absorbed while adjusting the bat trajectory near the time of impact, skilled bat control involving movement of the hand joints appeared to determine the bat head speed.
著者
阿江 数通 小池 関也 川村 卓 中島 亮一
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.1, pp.135-149, 2019-06-17 (Released:2019-06-25)
参考文献数
40

The purpose of this study was to investigate the kinematic characteristics of the lower limbs in relation to the rotation movement of the body based on the moment of the ground reaction force. Twenty-two male collegiate baseball players (age: 19.8 ± 1.3 yr, height 1.75 ± 0.04 m, body mass 73.9 ± 6.2 kg, athletic career:12.1 ± 2.1 yr) participated. They performed baseball tee-batting, set at middle ball height for the strike zone. Threedimensional coordinate data were acquired with a motion capture system (Vicon-MX), and ground reaction force data for both legs were acquired with 3 force platforms. High and low groups (HG and LG) were categorized by the mean peak moment around the vertical axis of the body’s center of gravity caused by the ground reaction force. The period analyzed was that from stride-side foot contact with ground until ball impact, and 2 phases were defined as follows: backward phase, stride-side foot contact with ground until the peak moment of the ground reaction force; forward phase, the end of the backward phase until ball impact. Statistical analysis was conducted using an independent t-test between HG and LG (p <0.05), and the effect size was calculated (small: d = 0.2; middle: d = 0.5; high: d = 0.8). In the backward phase, the flexion angle of both hips was greater in the HG than in the LG at event1 (pivot-side: d = 0.74; stride-side: d =0.97). The abduction angle of the pivot-side hip was significantly greater in the HG than in the LG (stride-side foot contact with ground: d = 0.94; peak moment of the ground reaction force: d = 1.44). In the forward phase, the external rotation angle of the pivot-side hip was significantly greater in the HG than in the LG (d = 1.02), which contributed to the inter-group difference in the internal rotation angle at the instant of stride-side foot contact. These results indicate that the motions of both hip joints acted to rotate the whole body around the vertical axis effectively. The knowledge obtained from this study should provide useful suggestions and insights into coaching for movements of the lower limbs in order to improve batting performance in relation to the rotational movement of the body.
著者
梶田 和宏 川村 卓 島田 一志 金堀 哲也 八木 快
出版者
The Japan Journal of Coaching Studies
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

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
川村 卓 小池 関也 阿江 数通
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.17038, (Released:2019-02-05)
参考文献数
22

This study examined the flow of energy in the right and left upper limbs of skilled baseball batters during the forward swing motion at different bat head speeds to obtain basic insights that would be useful for batting coaching. The subjects were 23 college baseball outfielders in university teams. The subjects were instructed to hit a ball toward the pitcher from a tee set at a mid-height position. Measurements were taken using 47 points on each subject’s body and 6 points on the bat for a total of 53 points, onto which reflective markers were attached. The 3D coordinates of each marker were measured using a 3D optical motion capture device (Vicon Motion Systems’ VICONMX, 12 cameras, 250 Hz). The variables in the kinetics of each hand were measured using a force detection sensor bat (1000 Hz). The subjects were separated into a faster group of 36.8±0.8 m/s and a slower group of 34.7±1.1 m/s for analysis. In terms of energy transmission, the data revealed that the faster group, in addition to showing additional torque on the knob side shoulder joints, were able to transmit more mechanical energy from the knob side shoulder joints to the end of the upper limbs than the slower group, and that this might be related to an efficient bat head speed. In addition, the faster group showed an increased positive torque power, and transmitted greater mechanical energy to the bat from the hand region. In other words, to prevent mechanical energy from being absorbed while adjusting the bat trajectory near the time of impact, skilled bat control involving movement of the hand joints appeared to determine the bat head speed.
著者
川村 卓 島田 一志 高橋 佳三 森本 吉謙 小池 関也 阿江 通良
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.0812080087, (Released:2008-12-10)
参考文献数
20
被引用文献数
25 4

The purpose of this study was to analyze three-dimensionally two groups of baseball strikers, i.e. high and low swing speed groups, and to compare the kinematics of their upper limb motion. Sixteen skilled male strikers were videotaped with two synchronized high-speed video cameras operating at 200 Hz. One trial in which the maximum bat head speed was achieved was selected for each subject and digitized to obtain three-dimensional coordinates of the segment end-points and the bat using a DLT technique. Subjects were divided into High (n=8) and Low (n=8) groups according to the bat head speed. The angles compared between the two groups were abduction-adduction, horizontal abduction-adduction, flexion-extension and internal-external rotation for both shoulders, flexion-extension for both elbows, supination-pronation for both forearms, radius-ulnar flexion, and dorsi-palmar flexion for both hands. The sequential data were normalized with the time from the point when the speed of the grip was over 3 m/s to the ball impact, and then averaged.
著者
金堀 哲也 山田 幸雄 會田 宏 島田 一志 川村 卓
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.59, no.1, pp.133-147, 2014 (Released:2014-06-13)
参考文献数
28
被引用文献数
6

The purpose of this study was to clarify the viewpoint of a well-experienced baseball coach when evaluating batting skills using kinematics indices. Method: First, three baseball coaches evaluated sixteen baseball players in their own teams. The players were divided subjectively into a first superior (FG) group and a second superior (SG) group according to batting ability. Next, the hitting motion of all sixteen players was captured using a VICON system (9 cameras, 250 Hz). We measured the speed of the batted and pitched ball, or the timing of release by the pitcher, using three synchronized high-speed cameras (250 Hz). From these kinematics data, we calculated several kinematics indices for each batter, focusing especially on the indices for motion of the lower extremities and trunk. In contrast, a well-experienced expert coach who had never met these players evaluated the hitting motion of each player using only motion films without the above kinematics indices, and similarly divided them into FG and SG. The evaluation of fourteen players agreed between the team coaches and the expert coach. The FG and the SG each comprised seven players. We analyzed these fourteen players using the kinematics indices, and clarified objectively the differences in hitting motion between the two groups. Results & Conclusions: The speed of swing, batted ball speed and physical index were approximately the same in the two groups. However, players in the FG group showed a significantly longer distance of center of gravity migration in step than those in the SG group. This might have been attributable to the hip abduction movement on the pivot side on the basis of kinematics indices (p<0.05). Moreover, players in the FG group took more time in step, and swung in a shorter time after landing on the stepped foot, relative to the players in the SG group (p<0.05). These results suggest that the well-experienced expert coaches paid particular attention to the above hitting motion rather than the speed of swing, batted ball speed and physical index as coaching points.
著者
川村 卓 島田 一志 高橋 佳三 森本 吉謙 小池 関也 阿江 通良
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.53, no.2, pp.423-438, 2008-12-10 (Released:2009-02-25)
参考文献数
20
被引用文献数
25 4

The purpose of this study was to analyze three-dimensionally two groups of baseball strikers, i.e. high and low swing speed groups, and to compare the kinematics of their upper limb motion. Sixteen skilled male strikers were videotaped with two synchronized high-speed video cameras operating at 200 Hz. One trial in which the maximum bat head speed was achieved was selected for each subject and digitized to obtain three-dimensional coordinates of the segment end-points and the bat using a DLT technique. Subjects were divided into High (n=8) and Low (n=8) groups according to the bat head speed. The angles compared between the two groups were abduction-adduction, horizontal abduction-adduction, flexion-extension and internal-external rotation for both shoulders, flexion-extension for both elbows, supination-pronation for both forearms, radius-ulnar flexion, and dorsi-palmar flexion for both hands. The sequential data were normalized with the time from the point when the speed of the grip was over 3 m/s to the ball impact, and then averaged.1 Angles of elbow extension, forearm supination of the top arm, and ulnar flexion of both hands were much changed. However, the angles of both shoulder joints, bottom elbow and bottom forearm showed little change.2. The High group showed significantly larger shoulder adduction and horizontal adduction of a bottom arm than the Low group in 0–10% time and 50–70% time (p<0.05). The High group showed significantly smaller top elbow extension than the Low group in 40–70% time and 90–100% time (p<0.05).3. The High group showed significantly smaller top hand supination than the Low group in 100% time. In the time, the High group showed significantly larger bottom forearm pronation than the Low group in 50–70% time (p<0.05). The High group showed significantly larger dorsiflexion of the bottom hand than the Low group in 20–30% time (p<0.05).
著者
森本 吉謙 入澤 裕樹 坪井 俊樹 小野寺 和也 川村 卓
出版者
The Japan Journal of Coaching Studies
雑誌
コーチング学研究 (ISSN:21851646)
巻号頁・発行日
vol.32, no.2, pp.203-210, 2019-03-20 (Released:2019-09-02)
参考文献数
23

The purposes of this study were to investigate the relationship between competitive result and environmental factors in high school baseball. A questionnaire survey was conducted on 533 university students who belonged to the baseball club when they were in high school. The survey content was the following 11 items; 1. Highest competitive result, 2. Presence or absence of the sports recommendation entrance examination, 3. Presence or absence of the sports scholarship system, 4. Occupation of the head coach, 5. Presence or absence of the assistant coach, 6. Number of the assistant coach, 7. Occupation of the assistant coach, 8. Presence or absence of the selection system for enter the club, 9. Number of the members, 10. Type of school (public or private), 11. Presence or absence of the private facility. In case of high school duplication, only one answer was adopted, and other inappropriate invalid answers were excluded for totalization. Finally, 435 students were divided into national group (n=89), block group (n=82) and prefecture group (n=264), based on the best result of the team at the time of high school, and examined the relationship between the competitive result and each environmental factor. As a result, regarding the occupation of the head coach, the proportion of teachers in all groups was high, but in the other items, the relationship with the competitive result was indicated, and the possibility that the difference in these environments could affect the competitive result was shown.
著者
松尾 知之 平野 裕一 川村 卓
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.55, no.2, pp.343-362, 2010 (Released:2010-12-28)
参考文献数
43
被引用文献数
4

The purposes of this study were to elicit experiential knowledge from expert baseball pitchers and baseball coaches, to elucidate key coaching points related to movement in baseball pitching, to classify them into categories, and to investigate any commonality among them. Semi-structured interviews were conducted with four former Japanese professional baseball pitchers and seven expert high-performance (national level) Japanese baseball coaches. Each interviewee was requested to comment on the pitching of 25 amateur baseball pitchers (11 junior high school, 8 high school, and 6 collegiate baseball pitchers), which had been videotaped beforehand. The comments were recorded, dictated literally, and divided into segments on the basis of meaning unit. Based on the properties of the various meaning units, some were gathered and classified into categories. For this process, we conducted a member check and triangulation to improve reliability and validity. We extracted 3283 units and classified them into 14 general categories and 71 specific categories. The most frequent category was “trunk open and quick turn during the stride and arm cocking phases”. However, this accounted for only 5.5% of the total meaning units. The next most frequent categories were “weighting on the pivot foot in the balanced position and during the stride phase” (4.7%) and “the throwing arm movement during the stride phase” (4.6%). The contents of all categories covered various aspects of movement. Among the relatively frequent categories, a few elicited the same opinion among the interviewees, but some had different opinions even about the same pitcher. These results suggest that there is a diversity of coaching points among coaches, and that it is important to know the categories that are determinative and those that should be chosen selectively.
著者
峰松 美佳 後藤 真孝 川村 卓也 松澤 茂雄
出版者
情報処理学会
雑誌
情報処理学会論文誌 (ISSN:18827764)
巻号頁・発行日
vol.54, no.2, pp.551-560, 2013-02-15

同時により多くの情報を表示可能とするタイルドディスプレイシステムが注目を集めている.本論文では,ディスプレイの大型化に柔軟に対応することを目的とした,マルチコアレンダリングサーバの設計と実装について述べる.また,我々の特徴技術である,多段並列処理手法と背景補正ダブルフレームバッファ(FB)の効果を検証する.8CPUコアサーバを用いて性能評価した結果,フレームレートが,並列処理を行わない場合と比べて7.3倍,通常のダブルFBを利用する場合と比べて1.3倍向上することが確認できた.また,関連研究であるXvncと比較すると5倍のフレームレートが得られた.A tiled display system which enables to display large amount of data is gaining attention. In this paper, we propose multi-core rendering server architecture for a tiled display system which flexibly adapts to different display sizes. The proposed technology introduces multistage parallel processing method and background correction double FB (Frame Buffer). Evaluation using 8 CPU core server showed that the frame rate of the proposed technology increased by 7.3 times compared with single thread version, increased by 1.3 times compared with conventional double FB version, and increased by 5 times compared with Xvnc.
著者
阿江 数通 小池 関也 川村 卓
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.59, no.2, pp.431-452, 2014 (Released:2014-12-20)
参考文献数
43
被引用文献数
2 2

The purpose of this study was to clarify the kinetic features of the upper limbs at different hitting-point heights (high, middle, and low) during baseball tee-batting. Twenty-three collegiate male baseball players (age: 19.8±1.3 yr, height: 1.74±0.04 m, weight: 74.1±6.2 kg, athletic career: 12.0±2.1 yr) participated. Three-dimensional coordinate data were captured using a VICON-MX system (12-camera, 250 Hz), and kinetic data for each hand were collected using an instrumented bat equipped with 28 strain gauges (1000 Hz). Three tee-batting heights were set for each subject based on the upper and lower limits of the strike zone according to the rules of baseball. Kinetic variables for the upper limbs, such as joint torque, joint torque power, and mechanical work, were calculated. The period of forward swing motion was divided into down-swing and level-swing phases. The results are summarized as follows: 1) The extension torque and positive torque power at each individual shoulder joint were significantly greater at the low hitting-point height than at other heights. 2) The positive torque power for extension torque at each individual elbow joint in the last half of the down-swing phase was significantly greater at the low hitting-point height than at other heights. 3) Negative power for adduction/abduction torque at each individual shoulder joint in the level-swing phase was observed at the low hitting-point height. 4) The mechanical work done by joint torque about the flexion/extension and adduction/abduction axes at the shoulder, the flexion/extension axis at the elbow, and the palmar/dorsal flexion and radial/ulnar flexion axes at the wrist showed large and positive values, and differed significantly among hitting-point heights. These results indicate that 1) the flexion/extension torque at each individual shoulder joint contributes greatly to adjustment of the translational movement of the bat in the vertical direction during the down-swing phase, 2) the adduction/abduction torque at each individual shoulder joint exerts a larger proportion of the longitudinal force of the bat to withstand centrifugal force at a low hitting-point height than at other heights in the level swing phase, and 3) consequently, it tends to be more difficult to adjust the bat to the hitting-point at a low height in comparison with other heights.