著者

湯 海鵬 溝口 正人 豊島 進太郎

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.47, no.2, pp.155-162, 2002-03-10 (Released:2017-09-27)

---

The ball size for table tennis was recently changed in the revision made to the international rules by the ITTF (International Table Tennis Federation), and the new ball has been in use for official games since October 2000. The new rules stipulate that the diameter of the ball should now be 40mm (an increase from 38mm), and the weight of the ball should be 2.7g (an increase from 2.5g). It is estimated that the style of play and game tactics will change to some extent as a result of the new ball. The purpose of this study was to compare the hitting properties of the new ball in comparison with the old one, in order to clarify the influence on play. The reduction ratio of ball speed from the shooting point to the receiving point was calculated using a ball-shooting machine and a speed measurement system. Initial velocities and ball spins were calculated using a golf-swing robot and a high-speed video camera system. The robot hit the balls with different hitting speeds and hitting angles by a racket attached to the robot arm. An all-around wooden bat pasted with a reverse-soft rubber sheet was used. Average rally times for the two kinds of ball were measured, and three kinds of basic shot-drive, chop and serve-were made in the rallies by skilled payers. The following results were obtained: (1) The initial speed of the new ball was 1-2% less, and the ball spin was 5-20% less than for the old ball. (2) No difference in the speed reduction ratio was observed between the new ball and the old one. (3) The average rally time for the new ball was 2-4% longer than for the old ball for drive and chop shots.

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

---

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

張 禎 邵 建雄 潘 珍 金謙 樹 豊島 進太郎 湯 海鵬 Zhen ZHANG Jian-xiong SHAO Zhen PAN Itsuki KANAAKI Shintaro TOYOSHIMA Hai-peng TANG

雑誌

人間発達学研究 (ISSN:18848907)

巻号頁・発行日

vol.5, pp.23-29, 2014-03

著者

湯 海鵬 豊島 進太郎 星川 保 川端 昭夫

出版者

バイオメカニズム学会

雑誌

バイオメカニズム学会誌 (ISSN:02850885)

巻号頁・発行日

vol.27, no.1, pp.37-42, 2003-02-01

被引用文献数

4 5

---

本研究は,介護作業の中で,最も体に負担の大きいと言われる車椅子への移乗動作を三次元的撮影し,映像データに基づいて介護者の重心の変位,関節角度および身体エネルギーを算出した.理学療法士(PT)と社会福祉学専攻学生の介護動作との比較検討を行い,車椅子への移乗動作の特徴を明らかにした.学生に比べPTの作業時間と作業距離が短かった.身体の姿勢については,PTはできるだけ腰への負担を軽減するために,大腿の筋群を主に用いて被介護者を抱き上げ,腰掛けさせるという動作になっている.このような動作は,身体の上下動が大く,力学的仕事の量も多くなる可能性はあるが,腰の保護と腰痛の予防には有効な動作と考えられる.

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

---

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.