ADOLESCENCE

Growth and Physical Development

The increased rate of growth that occurs during adolescence is second only to the rate of growth that occurs during the first year of life. During this period, adolescents achieve the final 15 to 20 percent of their adult height, gain 50 percent of their adult body weight, and accumulate up to 40 percent of their adult skeletal mass.1 The peak period of growth usually occurs at sexual maturity rating (SMR) 2 to 3 in females and 3 to 4 in males. The mean age of the initiation of the growth spurt is 9 1/2 years in females and 11 1/2 years in males. The mean age of peak height velocity are 11 1/2 years in females and 13 1/2 years in males. For females, most physical growth is completed by about 2 years after menarche. (The mean age of menarche is 12 1/2 years.) Males begin their pubertal growth spurt about 2 years later than females, and they typically experience their major growth spurt and increase in muscle mass during middle adolescence.

During adolescence, strength increases in both males and females, and strength can be increased further by participation in strength-training programs, especially from mid-puberty onward.2-5 On average, the percentage of body fat in males remains the same, whereas the percentage of body fat in females increases significantly.2,5

Height and strength during and after puberty affect the ability of adolescents to compete in some sports, such as football and basketball. However, in other sports, such as tennis and soccer, these attributes may be less important. The age at which the pubertal growth spurt occurs and the speed with which adolescents experience puberty vary greatly and may affect participation in physical activity and sports. For example, although early-maturing boys are often the most successful participants in Little League, they may not be the best athletes in high school.2,4,5

Physical activity and nutrition can affect adolescents' energy levels and influence growth and body composition. Inadequate nutrition can delay sexual maturation, slow or stop linear growth, and compromise peak bone mass. Participating in regular physical activity and practicing healthy eating behaviors can help adolescents achieve normal body weight and body composition, thereby reducing their risk of obesity.

The changes associated with puberty can affect adolescents' satisfaction with their appearance. For males, the increased size and muscular development that come with physical maturation can improve their body image. However, physical maturation among females--in particular, the normal increase in body fat--may lead to dissatisfaction with their bodies, which may result in weight concerns and dieting.

Anticipatory guidance can help prepare adolescents and their parents for changes associated with puberty. Because adolescents are usually interested in their growth and development, health supervision visits provide an opportunity for health professionals to discuss the importance of healthy eating behaviors, regular physical activity, and a positive body image.

Cognitive capacities increase dramatically during adolescence. During early adolescence, adolescents have a growing capacity for abstract thought, but their thinking still tends to be concrete and oriented toward the present. During middle adolescence, they become more capable of problem solving and abstract and future-oriented thinking. During late adolescence, they continue to refine their ability to reason logically and solve problems. These cognitive changes can help adolescents understand the importance of physical activity, because adolescents are beginning to reflect on their behavior and understand its consequences.