著者
布目 寛幸 池上 康男
出版者
名古屋大学
雑誌
基盤研究(C)
巻号頁・発行日
2009

サッカーにおいてより速いボールを蹴ることは重要な能力のひとつである。日々のトレーニングを通じて選手達は以下に足部と脚の運動量を効果的にボールに伝える術を習得する。本研究では、子どもから青年期までのサッカー選手を対象にインステップキックにおけるボールインパクトの特性の横断的な変化を概観した。8歳~24歳までの選手(プロ選手を含む)を対象に2台の超高速度カメラを使い、ボールインパクト局面における下腿部、足部、ボールの動きを毎秒2000コマの速度で撮影した。3次元映像解析法から足部の3次元的な動きを定量化するとともに、よいボールインパクトの指標であるボール/足部速度比を求めた。さらにボールインパクトに有効なstriking mass(有効質量)との関係を求めた。ボールインパクト直前の足部速度、ボール初速度、ボール/足部速度比は年齢とともに一定の増加傾向を示した。ボールインパクト中の足部の動きは年齢を問わず、ほとんどの被検者で底屈、外転、外反していた。本研究ではAsami and Nolte(1983)による足関節の固定具合がよりボールと足部のインパクトの重要な要素であるという示唆とは異なり、前述した受動的な足関節の動作とボール/足部速度比との有効な関係をみつけることができなかった。(足部)有効質量は、被検者の体重(r=0. 89),足部質量(r=0. 91)およびボール/足部速度比(r=0. 89)と強い相関を示した。Lees and Nolan(1998)は、足関節の固定により、足部のみならず下腿部の質量を有効質量に加えることができると推測しているが、本研究の結果からは、足部がボールにその重心付近の適切な位置でインパクトするならば、サッカーインステップキックのボールインパクトは、ほぼボールと足部のみの衝突であると考えることができた。したがって、身体のサイズ≒足部の質量は、ボールインパクトの効率に大きな影響を与え、特に身体のサイズが小さい子どもはこの観点から技術的ではなく、物理的なハンデがあると考えられた。
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
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
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.