若年者の運動時乳房振動に関する実験的研究:ハイスピードカメラによる三次元動作解析

摘要

In order to design brassieres (bras) which effectively control breast vibration,the vibration of breasts was measured using high speed cameras during walking,running and jumping.The subjects consisted of eight young females with different sizes of breasts.By measuring skin viscoelasticity and compression of the breast,their relationships were compared with the breast vibration.The following results were obtained: 1.Thetbreasts showed characteristics of vibration locus on the x,z plane during walking,running and jumping.The bigger the breast the greater the vertical amplitude of vibration; 2.A time lag between the movement of the breast and the body was shown on the z plane due to the inertial influence; 3.The average of amplitude,speed and acceleration of outside measuring points are greater than inside measuring points during walking,running and jumping,so that it is important to control the vibration of the outside breast during exercise. 4.The breast size has a high correlation with the average of amplitude and speed in both vertical and horizontal direction during walking or running,and those in vertical direction only during jumping.The average amplitude exhibits a positive correlation with the recovery rate of skin and a negative correlation with the compression stress ratio F_10mm during running which showed that the softer the breast,the greater the vibration.%振動抑制に配慮したブラの設計を目的とし，ハイスピードカメラを用いて，歩行，走行，ジャンプ時の乳房振動を観察した.異なる乳房の大きさの若年女性8名を被験者として，皮膚粘弾性と乳房の圧縮性を測定，乳房振動との関係を検討した.主たる結果は以下のとおりである.(1)乳房x.z軸方向の振動軌跡は運動の種類によって特異的であり，乳房が大きいほど上下の振幅が大きい.(2)乳房の上下振動は，いずれの運動においても基体の動きとは時間的なズレを持って振動し，乳房振動には慣性の影響が大である.(3)いずれの運動も平均振幅，速度，加速度は，乳房外側2点は内側の2点より大きく，運動中の乳房外側の振動を抑制することが重要である.(4)乳房の大きさと，歩行·走行時の乳房上下·左右方向およびジャンプ時の上下方向の平均振幅，速度との間には，有意な高い正の相関が認められた.歩行·走行時の振幅は皮膚の回復率R7との間に正の，走行時の振幅は圧縮応力F_10mmと負の相関を示し，柔らかい乳房ほど大きく揺れることが示された.