During the preschool years, physical growth, neurologic growth, and maturation are quite rapid and apparent, with new skills being acquired at a rapid pace. This process continues throughout the middle years with a somewhat slower pace. As the child enters puberty, rapid development of physical and sexual characteristics becomes more apparent, accompanied by important psychosocial development. The onset and rate of progression of pubertal events vary considerably among adolescents; however, the changes occur in a predetermined sequence.1,2 The adolescent may perceive sport experiences quite differently based on the influences of several variables: the differences in physical and psychosocial development, states of adolescent development (early: 10–13 years of age; middle: 14–16 years of age; and late: 16–20 years of age), as well as those who mature early or late.3–8 Also, gender differences become more apparent and significant for sport participation during adolescence (Figure 2-1). Clinically, it is important to assess an adolescent’s sexual maturity rating (SMR) or Tanner staging (Figures 2-2, 2-3, and 2-4), because chronologic age does not necessarily correlate well with many physiologic and somatic changes. Skeletal maturity is best assessed by measurement of bone age.

Selected aspects of somatic, sexual, and skeletal growth and maturation during adolescence (especially relevant to sport participation and performance) and their developmental continuity and inter-relatedness have been the subject of extensive review in the literature.1,2,4,9,10–22

Weight

In males, the average weight gain during its peak is approximately 9 kg/y with a range of 6 to 12.5 kg/y; in females it is approximately 8 kg/y with a range of 5.5 to 10.5 kg/y.1,19,21 In males, the peaks of growth spurts in height, weight, and muscle occur at the same time, while in females these occur in sequence in that order.2,16

Height

Peak height velocity (PHV) refers to the maximal rate of linear growth during adolescence. Females reach PHV by 12 years of age during SMR 3, usually 6 to 12 months before menarche (onset of menstruation); their average gain is 8 cm/y, while the range is 6 to 10.5 cm/y.1,2,19 Males usually reach their peak height velocity by 14 years at SMR 4, with an average gain of 9 cm/y and a range of 7 to 12 cm/y.1,2,19 During the early growth spurt, growth of the shoulders in males and that of hips and pelvis in females are the most noticeable changes. In general, linear growth first occurs in the lower extremities, followed by the torso and then the upper extremities.

Body Composition

There are significant gender differences in changes in body composition as described in terms of fat mass (FM), fat free mass (FFM), and body fat distribution.8,9,13,17,20 In general, both males and females tend to increase both FM as well as FFM from the early to middle adolescent years.6 However, males may show a transient decrease in fat accumulation in extremities during PHV; females continue to gain fat through late adolescence. By SMR 4 and 5, the fat mass in females can reach twice that of males. There is a relatively predominant deposition of fat in lower trunk and thighs in females. The pattern of growth of FFM is similar to that noted for growth in height and weight. Body mass index (BMI) (weight in kg/stature in meters squared) has been shown to have a better correlation with FM than weight.23 The calculated value is compared to the population norm tables. One limitation of BMI is the fact that factors other than FM, such as muscle mass and bone mass, affect the numerator and may incorrectly give a high value in someone with high-muscle mass and not FM.17 Application of BMI in sports classified by weight categories has been found useful in such sports as wrestling, bodybuilding, and weightlifting.

Flexibility

Typically, skeletal growth precedes that of musculotendinous growth during early to midadolescence; this partly contributes to a relative decrease in musculotendinous flexibility in some adolescents, especially males.4,6,20 In general, females are more flexible compared with males. In males, overall flexibility tends to decrease from late childhood to midadolescence; in females, it tends to show a slight increase during early adolescence, plateauing by 14 or 15 years of age.8,16,20,21 Decreased flexibility is particularly noticeable in hamstrings and ankle dorsiflexors, especially in dancers and gymnasts.6,21 Flexibility is influenced by internal factors such as bone structure, muscle volume, and tissue elasticity (i.e., muscles, tendons, joint capsules, and ligaments). External factors, which influence flexibility include room temperature, warm-up time, and physical exercise.24

Muscle Growth and Strength

Growth in muscle mass is seen both in males and females during adolescence. Since androgens partly influence this growth, it is relatively more pronounced in males compared with females. There is also a linear increase in muscle strength in both males and females, with males showing a period of relative acceleration or spurt around age 13, females reach a plateau by age 15 with no apparent spurt.4,2,14,20 The peak increase in muscle strength follows a peak in muscle mass by approximately 12 months.2,8,20 The response to strength training is best seen during SMR 4 and 5 in both males and females.2,4,6,14,25

Bone Mass

Weight bearing and loading, along with proper diet, are essential to optimal bone growth. The largest percentage of lifetime acquisition of bone mineral density occurs during the second decade of life.10,12,13 Peak bone mass during adolescence is determined by many factors, including genetic influences, exercise, calcium intake, and hormonal status.10,13 Thus, lack of proper nutrition seen in some athletes who engage in drastic weight control measures may predispose them to deficiencies in bone mass accumulation.8,13

Implications of Early and Late Maturatizon

Early development is characterized by advanced bone age compared with chronologic age, and late development by delayed bone age compared with chronologic age.1,2,19 Early developing males may have PHV before 13 years of age, while females may reach PHV before 11 years of age; late developing males may not reach PHV before 15 years of age, while females may not reach PHV before 13 years of age.1,2,16,18,19,21,23,26

Boys, who mature early tend to be taller and have greater muscle mass, fat mass, as well as strength (i.e., arm, grip, and explosive) compared with average or late maturing boys; jumping and sprinting are examples of explosive strength. Adolescent boys who are late maturers are relatively smaller in stature, weaker, and less coordinated; they may experience frustration, anxiety, and disappointment when not being able to meet performance expectations while playing sports. They may even be ignored by peers as well as coaching staff.

In comparison to average or late maturing female peers, early maturing girls tend to be taller, have greater fat mass and fat free mass, greater weight for height, relatively shorter legs, and broader hips; however, this only gives them a modest (if any) advantage in sports. In fact, early maturing girls may be at a disadvantage socially, as well as in certain motor tasks, and may not be considered ideal for such sports as gymnastics, dancing, diving, and figure skating.21 On the other hand, girls who mature later are taller, have lower weight for height, less FM, relatively longer legs, and narrower hips; they may be at an advantage socially, perform better on tests of upper extremity strength, and are better suited for sports such as gymnastics and figure skating.21

Physical Growth and Development

Rapid changes in physical growth and motor skills characterize early adolescence. Many adolescents, especially males, begin to demonstrate special skills and talents during this time. Because, normally girls often experience the onset of puberty earlier than boys, they may become temporarily taller and heavier than boys of the same age. Differences in physical performance, early in adolescence are more strongly influenced by the age at the onset of puberty and environmental conditions than by the chronologic age.4,8,18,21,27,28 As adolescents become older, gender differences become increasingly more a function of environmental factors.

Physical differences can be dramatic in some adolescents, especially boys. A wide variability in the rate of progression of growth, physical skills, and overall development may contribute to increased concerns about body image in some adolescents. Increases in muscle mass, strength, and cardiopulmonary endurance that occur during puberty are greater than at any other age.2,6,20,21,29 Males show sharp increases in tasks that require muscle strength such as vertical or horizontal jumping, throwing, and sprinting; females show a gradual improvement or reach a plateau in their performance of these skills.6,16,18,21

Cognitive Development

Piaget contends that early adolescents are just beginning the Formal Operational Stage of cognitive development, with improved inductive and deductive reasoning abilities.30–33 While they develop prepositional logic in which they can think about thinking itself, they may also note an awakening sense of morality and altruism. Also, future time perspective has not been fully developed during early adolescence, and they are still at a concrete level of cognitive functioning.1,31,32,34 It should also be noted that some adolescents may never shift to this stage of thinking and remain at the concrete phase of thinking.

However, for many, there is a beginning of abstract thinking, analytical abilities, problem solving skills, and transitional skills.30,32,33,35–37 Selective attention and memory are more mature; they now have a cognitive ability to understand and remember complex strategies for sports such as football and basketball. During adolescence, the focus shifts away from acquisition to the cognitive aspects of language development, such as the ability to understand the semantics of language and the ability to use language to convey the variety and quality of information. Adolescents, at this age can understand the basic theories and concepts behind how a sport is played.38 They can use symbols, signs, and coded words to understand plays the coach or trainer is asking them to perform. They can use such language to communicate to others who understand the special language related to specific sport activities. They may still have some limitations, but with practice and patience will continue to grow in their use of this vital communication domain.

However, problems may arise as a result of this developing process.39 Since behavior and consequences are processed on a “here and now” basis, they often fail to extrapolate general rules of the game from one situation to another. Early adolescents may attribute success or failure in athletics to their uniqueness and may fail to connect regular training or practice to future athletic success. Early adolescents are preoccupied with physical (bodily) concerns and may respond to minor injuries with out-of-proportion reactions. Normal comparisons (and finding differences or similarities) between self and peers may cause the adolescent to be either distressed or feel superior.

As reasoning abilities become more sophisticated, some adolescents may argue and disagree with adults; arguments with their coaches, trainers, or referees may result in penalties or ejections from games. Because, these adolescents lack life experience, their magical thinking tendency may be problematic for some. They still need approval from their peers and may go to great lengths, even get in trouble to gain their acceptance. They may impulsively engage in high-risk taking behaviors, much to the dismay of parents and coaches.

Psychosocial Development

From approximately 11 to 14 years of age, a convergence of body image and motor skills occurs.38 Sport participation provides an early opportunity for independence and emancipation.15,29 Comparison with peers, worry over perceived physical differences, and sexual relationships may occupy much of their time.1,5,40,41 Peers and adults in the environment can independently weigh consequences of their decisions before taking action. Peer acceptance is important, but the approval and support from family are still significant guiding forces.32,33 These adolescents are also able to enjoy and take pride in increasingly complex accomplishments in sports as well as academics and begin to improve their self-image. Some studies suggest that adolescents who experience consistent successes tend to develop a positive self-image, while those who experience repeated failures tend to develop a less healthy self-image.3,5,21,36,42