Martin Wallace, age 13, of Gastonia, N.C., for his question:
WHAT ARE GROWING PAINS?
Because children grow at different rates, scientists have worked out a system for assigning developmental ages rather than chronicle ages to growing children. They have developed an atlas of standards based on the growth of bones in the skeleton. An X ray is taken of a person's hand and wrist and is compared with the atlas to establish a skeletal age.
Growth of the human body is a slow process that continues about 20 years. There are a number of periods of time during this span, however, when growth is quite rapid. One period of rapid growth is the two month time just before birth and another is a two year stretch during adolescence.
An unborn baby after seven months of development usually weighs about two pounds and is about 15 inches in length. Two months later, when the baby is born, the brand new human will usually weigh about six or eight pounds and measure from 19 to 21 inches in length. This is a lot of growth in a very short period of time.
A newborn baby grows rather fast during the first two years of life. Then the rate slows until adolescence is reached. An "adolescent spurt" occurs with most boys between 13 and 15 and with girls about two years earlier.
During the teen spurt a boy may gain from 4 to 12 inches in height. The spurt can vary with the individual and may actually start at any time between 12 and 17.
Many adolescents suffer with what are called growing pains. When young people have actual pains in their limbs, it is sometimes caused by rheumatic origins. Generally speaking, however, there are no specific pains in the body caused by growth of the body. The term is used to describe the psychological traumas that occur during the sensitive period of adolescence. "Growing pains" are the knocks a person receives as he passes from childhood to adulthood.
Until the start of adolescent years, boys and girls are generally about the same size. Then the girl will usually have her spurt of growth ahead of the boy's. Men
are generally larger than women because their adolescent spurt of growth starts two years later and boys have a greater maximum growth rate than girls.
Most humans stop growing some time between 18 and 30. And a person is usually at his tallest when he is 20 years old. After growing has stopped, a person will actually start to shrink. The decrease in height is so slow that it can hardly be noticed even over a long span of years, but it is caused by a thinning of the pads of cartilage that grow between the bones of the backbone. The thinning starts when regular growth stops.