How to calculate the height with the length of footprints?

The material basis of human height is bones. Height is mainly related to the long bones of the head, spine and lower limbs? The third part.

Experts remind that human physical development is a very complicated process, from top to bottom, from near to far. The head develops the earliest. The head length of a newborn is 1/2 of that of an adult, while the head length of a newborn is 1/4 of its own body length. In contrast, the development of lower limbs is late, and the newborn is only 1/4 of that of adults at birth. Therefore, the development of long bones of lower limbs after birth has the greatest influence on height.

Changes in the development ratio of various parts of the body from fetal development to adult development. Generally speaking, under normal circumstances, the birth time of a person is about 50 cm; 1 year-old is a 1 leap in height growth, which can grow to about 75 cm; 2 years old to about 85 cm; 3~7 years old, the annual increase of 6~ 15 cm. When most people reach the age of 1 1~ 12, they will grow to 155~ 160 cm. During this period, the height difference of most people is not very big.

However, with the advent of adolescence, height, like all organs, has experienced another leap. Genetic factors, nutritional status, physical exercise and other conditions make obvious differences between people. During this period, some people can increase their height by 6~7 cm every year, or even increase 10~ 13 cm. In junior high school, the height growth was very obvious. Often within a year or two, an innocent child will grow into a strong young man or a slim and beautiful girl.

After 17~ 18 years old, the growth rate of height obviously slows down until sexual maturity, that is, when girls 18~23 years old and boys are 22~25 years old, people's height is basically stereotyped.