A Study on Dimensional Analysis of Growth in Japanese : maturation

Abstract

Longitudinao growth of weight, chest-girth in relation to height in 55 boys and girls from age 6 to 18 are presented by a straight line in logarithmic scales. The straight line is divided into two or three parts at critical points. The first point apeares at the height between 120 and 125cm which correspond to the age from 7 to 9 years. The second point appeares at the height of 145cm in girls and between 151and 156cm in boys are considered as an index of maturity, because in most girls the menarche onset at the height a little taller than the height at the second poins. The height when the menarche appeared is closely 96% of the final height. The relation between the weight and chest-girth and height is presented by the following equation Y=bX^a (where X is height, Y is weight or chest-girth, " a " and " b " are constants). Constant " a " increases after critical point as the followings, a = 1.50, 2.46 and 5.50 in girls, a=1.46, 263 and 5.76 in boys in weight, while a=0.89, 2.71 in girls, and 0./2,3.23 in boys in chest-girth.