著者

蔭山 雅洋 岩本 峰明 杉山 敬 水谷 未来 金久 博昭 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.59, no.1, pp.189-201, 2014 (Released:2014-06-13)

参考文献数

31

被引用文献数

10 3

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The present study measured isometric muscular strength and mean power elicited by trunk twisting and trunk rotation during pitching in 28 university baseball pitchers aged 18-22 years. Based on the correlations among these measurements, the purpose of the study was to clarify 1) the influence of ball velocity on isometric muscular strength, trunk power output during the stretch-shortening cycle (SSC) and trunk rotation during pitching and 2) the influence of augmentation which is an index of SSC elicited by trunk rotation on trunk rotation during pitching. We also determined mean power and augmentation during concentric (CT) and SSC rebound (RT) throws of medicine balls weighing 5 kg while twisting the trunk. Augmentation while throwing the medicine ball was positively correlated with ball velocity (r=0.619, p<0.01), and augmentation of the medicine ball was positively correlated with torso rotation velocity at 18-27% and at 46-75% (r=0.398-0.542, p<0.05), and trunk twist velocity at 60-66% (r=0.378-0.395, p<0.05) of the second phase (from stride foot contact to instant release of the ball) during the pitching motion. In addition, pitched ball velocity was positively correlated with the velocities of pelvic rotation at 37-78% (r=0.378-0.488, p<0.05), torso rotation at 46-87% (r=0.391-0.711, p<0.05) and trunk twist at 63-83% (r=0.375-0.499, p<0.05) during the second phase of the pitching motion. These results indicate that pitchers with a larger ball velocity can use SSC movement generated by twisting the trunk, which effectively increases trunk rotation from the first half to middle of the second phase, and they can also increase trunk rotation during the second phase.

著者

蔭山 雅洋 鈴木 智晴 岩本 峰明 中島 一 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.60, no.2, pp.737-757, 2015 (Released:2015-12-18)

参考文献数

39

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The purpose of the present study was to clarify the profiles of the lower limb and trunk motion during baseball pitching in relation to their differences between the wind-up and the set positions, and to determine how the ball pitching velocity can be increased in the set position. The subjects were 12 high school baseball pitchers (age: 16.4±0.5 yr, height: 173.7±4.8 cm, weight: 64.8±8.1 kg). Pitching was assessed using a three-dimensional motion system and 2 multicomponent force plates. It was found that 1) the maximum and average pitched ball velocities were significantly lower in the set position than in the wind-up position, 2) the maximum ground-reaction force of the pivot and stride legs and the impulse of pivot during the stride phase (from the time of maximal stride knee height to the time of maximal anterior push-off force) were significantly lower in the set position than in the wind-up position, and 3) the maximum upper torso/trunk twist angular velocity and the pelvis/upper torso angular velocity at moment of the stride foot contact were significantly lower in the set position than in the wind-up position. These results indicate that 1) the ball pitching velocity in the set position is lower than in the wind-up position. In addition, the factors associated with this lower ball velocity are suggested to be 2) decreased momentum of the pivot leg and 3) decreased rotation motion of the trunk during the arm acceleration phase.   Therefore, in order to increase ball pitching velocity in the set position, increasing the moment to the rear of the pivot leg during a short period and improvement of lower limb strength/power with the extension movement of the hip and knee joint may be important factors.

著者

蔭山 雅洋 岩本 峰明 杉山 敬 水谷 未来 金久 博昭 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

pp.13014, (Released:2014-04-04)

参考文献数

31

被引用文献数

6 3

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The present study measured isometric muscular strength and mean power elicited by trunk twisting and trunk rotation during pitching in 28 university baseball pitchers aged 18-22 years. Based on the correlations among these measurements, the purpose of the study was to clarify 1) the influence of ball velocity on isometric muscular strength, trunk power output during the stretch-shortening cycle (SSC) and trunk rotation during pitching and 2) the influence of augmentation which is an index of SSC elicited by trunk rotation on trunk rotation during pitching. We also determined mean power and augmentation during concentric (CT) and SSC rebound (RT) throws of medicine balls weighing 5 kg while twisting the trunk. Augmentation while throwing the medicine ball was positively correlated with ball velocity (r=0.619, p<0.01), and augmentation of the medicine ball was positively correlated with torso rotation velocity at 18-27% and at 46-75% (r=0.398-0.542, p<0.05), and trunk twist velocity at 60-66% (r=0.378-0.395, p<0.05) of the second phase (from stride foot contact to instant release of the ball) during the pitching motion. In addition, pitched ball velocity was positively correlated with the velocities of pelvic rotation at 37-78% (r=0.378-0.488, p<0.05), torso rotation at 46-87% (r=0.391-0.711, p<0.05) and trunk twist at 63-83% (r=0.375-0.499, p<0.05) during the second phase of the pitching motion. These results indicate that pitchers with a larger ball velocity can use SSC movement generated by twisting the trunk, which effectively increases trunk rotation from the first half to middle of the second phase, and they can also increase trunk rotation during the second phase.