Theories about children's physical development

Updated April 17, 2017

Childhood development theories outline four initial periods in your child's life: infancy, early childhood, middle childhood and puberty. These periods are affected by the genetic make-up of your child and the environment in which he is reared.

Nature Versus Nurture

Physical development depends as much on nature as it does on the environment in which your child is reared. This concept is referred to as "nature versus nurture." Genetic make-up is inherited from his parents and set at conception. These genetic traits determine the potential for such matters as height and general muscle development; this is nature's influence.

Nurture, the child's environment and experiences, influences overall health and activity levels which contribute to his physical development because his environment is the framework in which he physically interacts with the world.


Some abilities are fully developed at birth such as smell and hearing. Proper vision, however, takes time to develop. Infants can't clearly see far way objects. Their vision is only 20/600, so they can only see objects about eight to 14 inches away. Developing depth perception and focusing on distant objects take up to nine months.

By his first birthday, your baby will triple his weight, growing almost 10 inches in length. Subsequently, the growth rate slows; two and half inches per year is normal.

Along with physical growth, sensory development and motor skills discovery are the primary changes taking place. Your baby begins to touch, feel and taste objects, building a bank of information for future reference. This is a time of simple motor skill development. The baby can grasp, begin to move body parts at will, and later, begin to sit up, crawl, play with objects, walk, fall down and get back up.

Physical Growth and Development

The growth between two and seven years is less than the previous two. She will grow about two and a half inches per year with weight accumulation of about five to seven pounds per year, but she will begin to lose her baby fat. Girls will still have more fat the boys and boys more muscle than girls. Another important change during this time is that your child's daily caloric requirement is markedly higher, requiring about 1,700 calories per day.

Middle Childhood

Children seven to 12 years old develop greater control of their motor skills, allowing them to accomplish more complex tasks than in early childhood. In this period, your child will begin to ride bikes, skate, skipping rope and play other more physical games. These activities involve large muscle groups and gross motor skills in which boys generally outperform girls. Girls, however, do better at fine motor skill tasks. Fine motor skills, such as painting and drawing, require more dexterity and involve the smaller muscle groups such as hands and fingers.

Your child will put on weight at a rate of five to seven pounds per year and grow two to three inches per year. By the end of this period, boys should be about 4.8 feet tall and girls 4.83 feet tall. Body fat continues to decline, and by age 12, most baby fat is gone.


In this pubescent period (8 to 15), a child's body moves from childhood to adulthood. Puberty usually lasts two to five years. Girls (8 to 13 years old) generally began this transition earlier than boys (10 to 15 years old). Their bodies begin to take on characteristics of an adult. This includes sexual development and drastic changes in body contours that no longer resemble that of a child.

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About the Author

Asba Lee is a former IT consultant who specialized in network administration and application development. Now a writer and academic instructor, Lee instructs GMAT, GRE and SAT courses. Lee loves to research and writes to learn new things, testing his thoughts and opinions.