Not all youth have the same characteristics as they grow, but several key traits are common to many children in an age group.

Early Childhood (6 to 9 years)

• Children grow slowly, gaining on average about 2-½ inches and 8 pounds a year.
• Large muscles are developing, making it easy for children to run and throw.
• Children become better at motor skills as their small muscles begin to grow.
• They also have more strength, better coordination, balance and reaction time.

Middle Childhood (10 to 12 years)

• Puberty begins in middle childhood, with fast growth and bodily changes related to sexual development.
• Physical growth occurs faster than intellectual, emotional and social development.
• Some children appear awkward, due to uneven growth in bones, muscles and organs.
• Motor skills improve as small muscles develop more quickly.

Early Teens (13 to 15 years)

• Boys begin their growth spurt and by age 15, are generally taller, heavier and more muscular than girls.
• Puberty continues: body changes and sexual development are noticeable in early teens.
• There is an increased need for sleep and physical rest.

Late Teens (16 to 18 years)

• Physical changes begin to level off.
• By 16, boys have stopped growing but their muscles still are developing.
• Boys are generally taller and heavier than girls.
• Late teens have reached their full height and other adult physical milestones.