Studies on the Functional Growth and Development in the Japanese

Abstract

The authoress investigated into the functional growth and development in the Japanese of both sexes, ranging from 4 to 20 years of age. The number of examinees amounted to about 3000. The result obtained is as follows:
A. Growth curves were plotted for various functional data, and the growth pattern and annual increment for each functional data were established.
1. Growth pattern:
1) The growth patterns of grasping power, back muscular power, vital capacity and basal metabolic rate per day show the sigmoid curve of Scammon's general type as those of height, body weight and the girth of the chest. The following specific features of the growth pattern is observed.
(1) Four periods on this curve can be identified.
(2) A rapid spurt at puberty is distinct.
(3) The sexual difference is distinct.
(4) Intersection phenomenon between males and females is not seen.
2) The growth pattern of Emmert's test and tapping test show the curve of -typical neural type, with the following fundamental feature:
(1) This curve is asymtotic to an adult level.
(2) The curve has a positive acceleration up to the age from 5 to 10 years.
(3) A rapid spurt at puberty is not seen.
(4) The sexual difference is not seen. The growth curve of standing broad jump is similar to the curve of neural type.
The growth curves of reaction time and the approximate time of rotation of eyeballs is reverse to that of neural type.
3) The growth curves of standing broad jump and maximal blood pressure are linear. In these curves constant growth of each year is seen but a rapid spurt is not seen.
4) The curve of basal metabolic rate per square meter per hour of male and female attain a maximum at the age of 2 years followed by decrease through maturity.
2. Annual increment:
Growth pattern of the function in the Japanese can be divided into 3 groups with regard to the speed of growth.
1) First group: The growth of basal metabolic rate per square meter per hour attain a maximum at the age of 2 years.
2) Second group: The growth of Emmert's test, maximal blood pressure, standing broad jump and tapping test is slower than that of the first group.
3 Third group: The growth of reaction time, approximate value of rotation time of eyeballs, vital capacity, grasping power is the slowest. The second derivative with regard to time, or the acceleration of the speed of functional growth in the Japanese is great in the juvenile period and at the age of 17-18 years is gradually adjusted and shortened and at the age of 20 years becomes zero.
B. Growth equations were fitted to the curves, and the following equations of functional growth in the Japanese were obtained. The difference between observed values and calculated values is small. These equations and their curves proved very useful for studies on growth process, establishment of standard values and smoothing up of the growth curve.
1) The growth equation for grasping power and back muscular power. a logistic equation.
2) The growth equation for standing broad jump: Male: y=a+bx, a linear equation.
Female: a hyperbolic equation.
3) The growth equation for vital capacity.
a linesr equation.
4) The growth equation for blood pressure:
a logistic equation.
5) The growth equation for tapping test:
a logistic equation.
6) The growth equation for reaction time and approximate value of rotation of eyeballs:
a parabolic equation.
7) The growth equation for Emmert's test:
a logistic equation.
8) The growth equation for basal metabolic rate per square meter per hour:
a logistic curve.