In order to examine the characteristics and qualities of balls used in sports activities, we investigated 36 balls for volleyball, basketball, handball and football for weight, circumference, impact power and elasticity by the special ball tester and computer system in the Laboratory of Physical Education, University of Tokyo.
　As the result of these tests, we found some individual differences between each ball manufacturer in weight, circumference, impact power and elasticity even in similar type of ball.
　As the conclusion of this study, we suggest that all sports federation should adopt this kind of scientific objective test procedures such as impact power, elasticity and endurance test when they decide on the ball officialization to avoid the variable influences on their skills and to keep the same conditions for training situations as in actual sports games.

DESCENTE SPORTS SCIENCE Vol.3/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE