From ages 7 to 12, children grow in both height and weight, though not as quickly as they did as preschoolers, according to CliffsNotes.com's guide to human development. These years are a time of growth spurts and milestones on the path to sexual maturation. Illnesses come less frequently in middle childhood, says the CliffNotes guide, and normal growth signals good health, according to KidsHealth.org.
Features
The onset of puberty and the physical changes that accompany it are the most significant features of middle childhood. For girls, development of the breasts is usually the first harbinger of puberty; it may begin as early as age 8 or as late as age 13. Menstruation begins, on average, at age 12.5. Boys may display signs of puberty as early as 10 or as late as 16. These include voice change, the appearance of underarm and facial hair, and the enlargement of the Adam's apple.
Size
Boys and girls get 2 to 3 inches taller and about 7 lb. heavier each year during middle childhood, the CliffsNotes guide says. Girls, on average, begin displaying signs of puberty, and have the corresponding growth spurt, about two years before boys. They may temporarily be bigger than their male age mates, but the boys catch up and then exceed the girls as their hormones surge. Boys begin their most prolific period of growth around age 12.
Effects
As their muscles and bones grow, so do kids' athletic abilities, according to the CliffsNotes guide. Coordination improves, along with speed and strength. Gross motor skills, such as leaping, running, throwing, catching, climbing and balancing, become easier. Fine-motor skills, using small movements to perform tasks such as tying shoes, writing and playing a musical instrument, also progress.
Considerations
A child's growth parameters are largely hereditary, according to KidsHealth.org. Genes will play the largest role in how tall he will be and what shape she will have. Other factors, however, can come into play, including diet, sleep patterns and exercise. In countries with widespread poor nutrition, children tend to be shorter, the CliffNotes guide says. Ethnic group, environment, disease and access to medical care can affect growth rates and other aspects of physical development.
Prevention
During middle childhood, boys and girls will become more interested in how they're growing and may worry about their appearance. For girls, the biggest concern is often weight, and for boys it's height, KidsHealth.org says. Parents can help their children develop positive attitudes about themselves by putting the emphasis on being healthy. They can't change their genetic makeup, but they can try to make the most of it.
