CHAPTER 4

SPECIFIC CONSIDERATIONS FOR THE CHILD AND
ADOLESCENT ATHLETESports medicine physicians must be familiar with the normal patterns of growthand development of the child and adolescent, in order to detect any abnormal
patterns, and make appropriate judgments. This will allow the physician todetect any deviations during the pre-participation examination, guide children
into appropriate activities, aid them in setting realistic goals concerning sports
participation, and provide guidance to the community and coaches in the design ofsafe and effective training and sports programmes.
A. Developmental Levels (see Table 4-1)

1. Early Childhood (ages 3–5 years)
a. Vision: not fully mature (difﬁculty in tracking moving objects and judging
velocity)b. Balance: paradoxical decrease at 4–5 years due to overload in integrating
visual and proprioceptive input.
c. Motor Skills: Age 4—run, kick, hop, throw (20%), catch (30%)
d. Learning Ability: short attention span; easily distracted; need instruction via
auditory and visual input.
e. Activity Recommendations: PLAY in a closed system (few variables,
constant conditions); walk, run, swim, tumble. Organised sports and competition may INTERFERE with learning.
2. Childhood (ages 6–9)
a. Vision: tracks speed and direction of moving objects with difﬁculty.
b. Balance: automatic by age 7.
c. Motor Skills: age 6—basic overhead throw developed; age 8—running skills
matured.
d. Learning Ability: short attention span; easily distracted; lacks rapid decision
making; needs verbal and visual instruction; cooperation improved.
e. Activity Recommendations: Skills acquisition in a closed system (run, swim,
gymnastics); recreational play; low level organised sports.

3. Late Childhood (ages 10–12)
a. Vision: adult pattern.
b. Balance: improved; declines at puberty during peak height velocity (Tannerstage 3).
c. Motor Skills: complex skills develop, but postural control may deteriorate(uncoordinated body segment growth patterns).

Farsighted

Recognise that swimming
programmes and exercise
programmes of no advantage; encourage free play;provide safe, unstructured
play environment

Free play

VisionGuidelines forSports Participation

Recommended
Activities

Walking, running, swimming, tumbling, throwing,catching

Avoid competition; provide
limited instruction verballyand by demonstration;emphasise fun play

Farsighted; eye movements imprecise; trackingof speed and direction ofmoving objects difﬁcult

Swimming, running, gymnastics, entry-level soccer andbaseball; complex-skill sports
such as football, hockey,
basketball, and wrestling are
difﬁcult

Keep competition minimal;
keep rules of sport ﬂexible;
emphasise fundamental
skills; keep instruction time
short

Tracking of speed anddirection of moving objects
improved, but still difﬁcult

Response to training mini- Attention span short;
Attention span limited;
mal; beneﬁts of training not attention overexclusive;
attention overinclusive;
long-term
response to training limited cooperation improved

Late Childhood(10–12 years)

Entry-level football, basketball, wrestling, and othercontact/collision sports

Minimise competition;emphasise fundamental andtransition skills; decrease
intensity of sports involvement at puberty

Patterns same as for adults

Attention selective;
memory strategies used

Fundamental skills improved; Transitional skills improved;balance control declines attransitional skills begin;pubertybalance control becomes
automatic

Learning Skills

Fundamental skills limited;balance skills limited

Childhood(6–9 years)

Skills primarily reﬂex;
posture depends on visual
input

Early Childhood(3–5 years)

Motor Skills

Infancy(0–2 years)

Table 4-1. Developmental characteristics of and sports participation guidelines for various age groups.

CHAPTER 4, GROWTH AND DEVELOPMENTCHAPTER 4, GROWTH AND DEVELOPMENT

d. Learning Ability: integrate information from multiple sources; respond toverbal instruction.
e. Sport Recommendations: continue fundamental and transitional skills;
successful in skill and team sports, low level competitive sports.
B. Adolescent Growth and Maturation

1. Endocrinology
Prior to puberty, the hypothalamic-pituitary-gonadal feedback system isoperative in a negative mode, and hormone levels remain low. With the onset ofpuberty, feedback sensitivity is diminished. This allows increased synthesis andsecretion of hypothalamic gonadotrophin-releasing hormone (GnRH), which
stimulates the anterior pituitary to produce gonadotrophins (LH and FSH) withsubsequent rises in the gonadal sex steroids estrogen and testosterone.
2. Stages of Growth and Development
Growth and development at puberty occur in an orderly fashion, as describedby Tanner. In general, the onset of pubertal maturation occurs earlier in girls thanin boys. On average, the height spurt in girls occurs about two years earlier than inboys, with a peak height velocity at age 12 for girls, and age 14 for boys. This mayvary, depending upon the nutritional status and geographic location of the subjects.
(See Figures 4-1 and 4-2, and Table 4-2.)
Tanner’s Sexual Maturation Ratings (Table 4-3) have been recommended as ameans of determining a child’s readiness to participate in certain sports, especiallythose involving complex skills, teamwork, and body contact.
23

Height velocity (cm/year)

12
11
10
9

Girls

8

Boys

7
6
5
4
3
2
1
0
1

2

3

4

5

6

7

8

9

10 11 12 13 14 15 16 17 18 19

Age (years)

Figure 4-1. Fiftieth percentile height velocity curve for American boys and girls (Slap 1986).

CHAPTER 4, GROWTH AND DEVELOPMENT

Table 4-2. Typical timing of normal pubertal events in girls and boys
(SMR=Sexual Maturity Rating—Tanner).
Event

Girls

Boys

onset of puberty

10 years (8–14 years)

12 years (9–15 years)

ﬁrst sign

breast bud

testicular enlargement

PHV

12 years
SMR = 2–3

14 years
SMR = 3 –4

peak weight gain

6 months after PHV

end of growth andmaturationGirls

16.5 years

15–18 months later
than girls

Height spurt
9.5–14.5
Menarche

10–16.5
8–13

Breast9

3

2

Pubic hair
8

2

10

4

3

11

5

4

13–18

5

12
13
Age (years)

14

15

16

17

Apex
strength
spurt

Boys

Height spurt
13.5–17.5

10.5–16

Testis

9.5–13.5* G rating

9

13.5–17
2

Pubic hair8

12.5–16.5

10.5–14.5

Penis

3
2

10

11

4

5

3

4

5

12
13
Age (years)

14

15

16

Figure 4-2. Sequence of pubertal events (Slap 1986). (*Genitalia)

17

CHAPTER 4, GROWTH AND DEVELOPMENT

Table 4-3. Tanner’s stages of sexual maturation in girls (a) and boys (b).
a. Sexual Maturing Ratings (SMR) in girls (Tanner ratings)
Stage
1

Pubic Hair
Preadolescent

Breasts
Preadolescent

1
2

3

4

5

Sparse, slightly
pigmented,
straight, at medial
border of labia
Darker, beginningto curl, increased
amountBreast and papillaelevated as small
mound, areolar diameter increased
Breast and areolaenlarged, without
contour separation

Coarse, curly,
abundant, butamount less thanin adult
Adult feminine
triangle, spread tomedial surface ofthighsAreola and papillaform secondary
mound
Mature, nipple
projects, areolapart of generalbreast contour

2

3

4

5

b. Sexual Maturing Ratings (SMR) in boys (Tanner ratings)
Stage
1

Pubic Hair
None

Penis
Preadolescent

TestesPreadolescent

1
2

3

4

5

Scanty, long,slightly pigmented

Slight enlargement

Enlarged,scrotum pink,
texturechangedLargerDarker, begins
to curl, small
amountLongerResembles
adult type but
less in quantity;
coarse, curly
Adult distribution, spread tomedial thighs

Larger, glans
and breadth
increased

Larger, scrotum darker

Adult

Adult

2

3

4

5

CHAPTER 4, GROWTH AND DEVELOPMENT

3. Clinical Conditions and Maturation Levels
A number of clinical conditions are associated with certain stages of maturation(Table 4-4).
Table 4-4. Clinical factors and Sexual Maturity Ratings (Tanner stages).
Clinical Factor

Sexual Maturity Rating (SMR)

Hematocrit rise (male)

2–5

Male gynecomastia

2 or 3Slipped capital femoral epiphysis

2 or 3

Worsening idiopathic scoliosis

2–4

Osgood-Schlatter’s disease

3

Body composition changes markedly at puberty, as a result of rises in sex
steroids secretion. Males exhibit a typical growth in muscle mass, while females
show a deposition of fat in the estrogen-sensitive areas of the hips, thighs, andbreasts (Figure 4-3).
40
Females30

FAT GAIN(Log Units/year)

20
Males

10
0
-10
-20
-30
6

8

10

12

14

16

Age (years)
Figure 4-3. Mean increment in fat in boys and girls based on skinfold
measurements at four sites (Tanner 1955).

CHAPTER 4, GROWTH AND DEVELOPMENT

C. Abnormal Patterns of Development

1. Precocious Puberty
Precocious puberty is deﬁned as showing signs of the onset of puberty prior toage 8 in girls, and age 9 in boys.
2. Delayed Puberty
Delayed puberty is deﬁned as:a. Female—lack of evidence of breast development by age 13.
b. Male—no signs of testicular enlargement by age 14 1/2.
c. Either sex—children who fail to progress normally through puberty.
3. Primary Amenorrhea
Primary amenorrhea is deﬁned as the absence of menarche in a female ofreproductive age. Signs include:a. Delay of menarche beyond age 16.
b. Absence of menarche more than four years after thelarche (onset of breast
development).
(See also Chapter 13, Part 1, Endocrine/Menstrual Factors.)
D. Musculoskeletal Growth and Development

1. Regulation of Musculoskeletal GrowthBone responds to a wide variety of growth stimulators, including growth
hormone, testosterone, sulfation factor, thyroxine, parathyroid hormone, andinsulin-like growth factor. Muscle lengthens in response to stretch; growth occurs
in the region of the musculo-tendinous junction. The maximum potential for growthis determined genetically. However, this potential can be attained only if there isadequate nutrition, physical activity, and good general health.
2. Bone Growth: Deﬁnitions (see Figure 4-4)
a. Epiphysis—the end of the long bone that is bordered by the growth plate(physis) and by articular cartilage.
b. Metaphysis—the ﬂared portion of the bone that is between the epiphysis
and the diaphysis.
c. Diaphysis—the shaft of the long bone.
d. Apophysis—the site of attachment of musculo-skeletal structures to thelong bone; it is extra-articular.
3. Growth of Long Bones
a. Longitudinal GrowthLongitudinal growth occurs at the epiphyseal growth plate (physis) andat the articular cartilage. Chondrocytes divide, align longitudinally to form
columns, and begin to enlarge and calcify. In this fashion, the epiphysis
moves further away from the center of the bone.

CHAPTER 4, GROWTH AND DEVELOPMENT

b. Latitudinal Growth
The periosteum contributes to new bone formation from ﬁbroblasts, toenlarge the circumference of the long bones. The ring of Ranvier enlarges
the diameter of the physis.
Epiphysis
small (reserve)
cells

Apophysiscolumns
Apophysis

hypertrophy

Metaphysis
vascularinvasive
osteogenesis

Diaphysis

Figure 4-4. Bone growth.

c. Apophyseal Growthi. Physeal growth occurs as in a (see Figure 4-4), at the junction of themetaphysis and the apophysis.
ii. Periosteal and ﬁbro-cartilaginous formation of new bone occurs at thesite of tendinous insertions.
d. Growth Rate
Growth is very rapid during the ﬁrst two years of life, then slows to a
relatively constant rate, except for brief, intermittent spurts. During preadolescence there is another major growth spurt (peak height velocity).
Then the growth rate begins to plateau as maturity approaches.
E. Injuries to the Immature Skeleton—Musculo-skeletal Injuries Unique toChildren and Adolescents

1. Unique characteristics of the immature musculo-skeletal system:
a. Open growth plates afford both longitudinal and appositional growth.
b. There is a relative disproportion between long bone length and adjacentmusculature, as muscles lengthen in response to stretch.
c. The periosteum is thicker. This stabilises the bone, both intact and fractured.
The thicker periosteum requires more force to disrupt than in adults. Following a fracture, the vascular periosteum aids in rapid healing; however, it may
act as a deforming force as it contracts over time.
d. The long bones are more porous, so buckling (torus) fractures are morecommon.

CHAPTER 4, GROWTH AND DEVELOPMENT

e. Long bones are more “ﬂexible,” and may undergo plastic deformation aspart of a fracture.
f. Thicker, growing articular cartilage leads to chondral or osteo-chondral
fragmentation from over-use, especially at the distal femoral condyle, radialhead, and humeral head.
g. There is greater vascularity of the knee menisci. This allows for healing
more often than in the adult.
h. Different injury patterns occur at different ages, dependent upon the strengthof the adjacent structures at the particular skeletal age.
2. Special Considerations in Injury Assessment
In addition to the usual diagnostic considerations, additional factors must be kept
in mind when assessing injuries to the child and adolescent.
a. Acute Injuries
In evaluating all musculo-skeletal injuries, consider:i. Physeal injuries
ii. Congenital anomaliesiii. Neoplasms
iv. Infectionsin addition to the more common sprains and strains. During on-ﬁeld
examinations, DO NOT STRESS an injured joint, as it may cause further
physeal damage. DO an X-ray ﬁrst!
b. Over-use Injuries
Over-use injuries may affect all joints, and especially the physes. Consider:
i. Inﬂammatory processes—apophysitis; osteochondritis dissecans
ii. Metabolic diseases
iii. Neoplasms
iv. Infections
F. Physiological Characteristics of Children

1. Aerobic Capacity
Aerobic capacity (VO2 maximum) increases with age. However, in terms ofbody mass, when aerobic capacity is expressed in terms of ml/kg, maximal aerobic
power does not increase, and may even decrease in the second decade, with theincrease in the child’s fat mass.
2. Anaerobic Capacity
Anaerobic performance in children is much lower than in adolescents and adults.
This is likely due to the development of anaerobic enzyme systems, and also topoorer neuro-muscular control.

CHAPTER 4, GROWTH AND DEVELOPMENT

3. Energy Cost of Running
The metabolic costs of locomotion are higher in children, hence they have alower metabolic energy reserve (the difference between maximal and sub-maximalenergy cost). This is probably due to: 1) shorter stride length and faster leg turnover
during running; and, 2) greater co-contraction of antagonist muscles during activity.
Flexibility and relaxation training may help to reduce the energy costs of running,
and improve economy.
G. Effects of Training on the Child and Pre-adolescent

1. Measurement Problems
A variety of physiological changes in children and pre-adolescents might be
expected to accrue as a result of a training programme. However, it is difﬁcult toassess the degree of trainability of various systems, due to a variety of confounding
factors.
a. The role of normal growth and development is difﬁcult to differentiate
from the effects of training. For example, relative changes in maximum
oxygen uptake (ml/Kg) may be masked by changes in maximal heart rate,and increases in body fat mass.
b. Children may lack the discipline required for training that is intensive
enough to induce measurable physiologic changes.
c. Intense training may not be employed for fear of causing injuries.
d. Suitable control groups are difﬁcult to select, as they should not bechosen solely on the basis of age and sex.
e. Ethical and methodological problems limit the extent of studies, e.g.
muscle biopsies, invasive procedures, etc.
2. Probable Physiologic Changes
Despite these limitations, a number of studies have suggested that the major
physiological systems that respond to training in adults also respond in a similar
fashion in children, though not always to the same degree.
a. Aerobic capacity
Aerobic capacity may improve nearly as much as in adults. This capacity
may be limited by the lower hemoglobin seen in children, with consequent
lower oxygen-carrying capacity.
b. Anaerobic capacity
Anaerobic systems may not be sufﬁciently mature to adapt well to training,and hence may limit the ability to respond well to anaerobic activities such as
the 200m and 400m dashes.
c. Strength
Strength may improve relative to body size compared to older children,
though absolute gains may be small. Little muscle hypertrophy occurs, due
to low hormonal (testosterone) levels. Strength gains are due to improvement

CHAPTER 4, GROWTH AND DEVELOPMENT

in a number of neurological factors, including increased neural recruitment,
improved synchronisation of motor unit ﬁbres, and better motor skills coordination.
(See Table 4-5 for strength training guidelines.)
Table 4-5. Guidelines: strength training for children and adolescents.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

Pre-participation evaluation by a physician knowledgeable insportsmedicine
Good quality equipment suitable to the size and age of the athletesStrength training should be part of an overall conditioning andﬁtness programme
Supervision by a well-trained adult (National Strength and Conditioning Association)
Appropriate warm up and cool down period before and afterstrength training
Selection of sports-speciﬁc exercises appropriate to the level ofphysical and emotional maturity of the participant
Attention to proper technique: avoid Valsalva maneuver,hyperventilation, back hyperextension
Emphasis on dynamic concentric contractions as opposed to
eccentric overload exercises
Emphasis on sets of high repetitions at low resistance
Each exercise should be taken through the full range of motion
for maximum muscle development and to maintain ﬂexibility
Competition (weight lifting, power lifting, body building) should
be prohibited
Maximal lifts should not be performed until skeletal maturity(Tanner stage 5; see Table 4-3)
Programme design should be based on the principle of progressive
resistanceSample Programme Prescription• 1-3 sets of 6–10 exercises per session• Frequency of 2–3 sessions per week with rest day in between• Duration of 20–60 minutes per session• Progressive resistance:• Start at no resistance/weights until proper form is achieved• Then initiate resistance at the 6 repetition level, advance to 15 reps
• Weight then added in 1–3 lb (500–1500 g) increments until child can dojust 6 reps
• Advance again to 15 reps before increasing weights

CHAPTER 4, GROWTH AND DEVELOPMENT

d. Heat Adaptation
Children adapt less well to exercise in the heat, especially at temperatures
above skin temperature. Several factors are responsible for this discrepancy:
i. At any exercise level, children produce more metabolic heat per kg ofbody weight (i.e., are less efﬁcient).
ii. Their larger surface area/body weight ratio permits greater heatabsorption from the environment when air temperature exceeds skintemperature (approximately 32º–33º C). The smaller the child, thegreater the potential for heat absorption.
iii. Children produce less sweat. This is likely due to limitations inanaerobic energy production by sweat glands. Thus, the ability forevaporative cooling is lower. This is critical, as evaporation of sweat is
the most important means of heat dissipation during exercise, especially
under hot conditions.
iv. Children require longer to acclimatise to a hot climate. Several days areneeded for adjustment of the enzymatic and hormonal changes that affectthe sweating mechanisms. Fourteen days may be required for full
acclimatisation.
v. Hypohydration (lower body water content) has more profound effects
on children. During exercise, core temperature rises faster, affecting
motor performance and cognitive skills. Children must be trained todrink frequently (every 15–20 minutes) even when not thirsty. A drinkwith electrolytes (especially sodium) and carbohydrate enhances
palatability and ﬂuid consumption.
H. Guidelines for Youth Training Programmes

Effective, safe training programmes for young athletes must take into accountthe age, sex, and maturation levels of each child. The duration, intensity, andfrequency of training sessions will vary considerably, depending upon the above
factors. Children should be encouraged to participate in a wide variety of activities
and sports, and not be channeled into “specialisation” in one sport or event before
reaching the mid- or late-teen years.
It is difﬁcult to provide deﬁnite “dosages” of training for children who participate
in the varied event disciplines of athletics. However, some general guidelines havebeen developed, based upon practical experience as well as a knowledge of thedevelopmental levels of children (see Table 4-1).
All training sessions should be preceded by a suitable 20–30 minute warm-up
period with emphasis on gradually increasing activity and stretching of all muscle
groups, and followed by a gradual cooling down and further stretching.
1. Endurance Training (long distance running)
The recommended maximum competition distances for children of various ages
are shown in Table 4-6. The weekly training distance should not be more than twice

CHAPTER 4, GROWTH AND DEVELOPMENT

Table 4-6. Recommended maximum running distance at different ages.
Age (Years)

Distance

Under 9

3 km

9–11

5 km

12–14

10 km

15–16

Half marathon (21.1 km)

17

30 km

18

Marathon (42.2 km)

the recommended maximum competition distance. Runs or races up to 10 km in
length can be undertaken on a weekly basis for children aged 12–14; runs or races
over 10 km in length require longer recovery periods. Training frequency for thoseup to 14 years old should not exceed 3 times per week. Those aged 15–18 can train
up to 5 times per week.
2. Sprints
Training frequency for those up to 14 years old should not exceed 3 times per
week. Those aged 15–18 can train up to 5 times per week. The duration of eachsession should not exceed 1.5 hours, including a warm-up and stretching component.
3. Throwing Events (shot put, discus, javelin, hammer)
Injuries can be avoided in throwing events if the correct technique is developedfor each throwing discipline. Training frequency and duration should follow thefollowing guidelines:
a. No more than 3 training sessions per week.
b. Each session should not exceed 1.5 hours (including warm-up).
c. The total number of throws permitted for each session should not exceed
20 for athletes up to 14 years old and 40 for those between 15 and 18
years old.
4. Jumping Events (long jump, triple jump, high jump, pole vault)
Training frequency and duration should follow the following guidelines—
a. Each session should be no longer than 1.5 hours (including warm-up).
b. Athletes up to 14 years old should not perform more than 3 sessions per
week with a maximum of 10 jumps per session.
c. Athletes from 15 to 18 years old should not perform more than 5 sessions
per week with a maximum of 20 jumps per session.

CHAPTER 4, GROWTH AND DEVELOPMENT

I. Roles of the Parents and CoachThe collaborative involvement and support of the parents and coach is essential if
children are to achieve an enjoyable and successful experience in sports. Unreasonable
demands and expectations from adults are a common cause for a child’s dropping outof sport.
The child’s reaction to this pressure may manifest itself in a wide variety ofpsychosomatic symptoms that may come to the attention of the sports physician.
These may include headaches, gastro-intestinal disturbances, muscle aches outof proportion to the training load, and even proneness to injury in order to avoid
participation. Guidelines for avoiding such situations are seen in Table 4-7.
Table 4-7. Guidelines for parents.
• Encourage children to participate if they are interested.
• Focus on the child’s effort/performance, not the outcome of the events.
• Honest effort is as important as victory.
• Encourage children to participate according to the rules.
• Never ridicule.
• Children learn best from example. Applaud good plays by all teams.
• Do not question ofﬁcials’ judgement in public.
• Support efforts to remove verbal and physical abuse.
• Recognise the value and importance of volunteer coaches.

J. Special Considerations in Injury Rehabilitation

1. Goals of the Rehabilitation Programmea. Prevent recurrence of the injury or related injuries.
b. Restore muscle strength to full power, strength, and endurance.
c. Regain ﬂexibility and coordination.
d. Restore full performance capability.
2. Principles of Rehabilitationa. Special Problems
i. Short attention span.
ii. Unable to comprehend need for rehabilitation programmeiii. Teenagers feel invulnerable to injury.
iv. Feel set apart from peers.
b. Application of Principles
i. Set a deﬁned time limit for meeting goals—no more than two months.

CHAPTER 4, GROWTH AND DEVELOPMENT

ii. Make the patient an active participant in the programme by using active
exercises. Control pain and swelling so the rehabilitation programme
can begin as soon as possible.
iii. Use short periods of activity.
iv. Utilise a small number of exercises, done correctly.
v. Make progress apparent by using many intermediate goals. Reward thepatient for attaining each goal.
vi. Integrate the programme into the patient’s regular schedule, i.e., while
watching TV, talking on phone, etc.
c. Special Rehabilitation Considerations for Children
i. Flexibility and strengthening must be stressed. Muscles may be relatively short compared to bones, especially during periods of rapid growth.
Non-ballistic stretching must be taught.
ii. Exercise programmes must be supervised carefully.
iii. Machines must be adjusted to the child’s frame.
iv. Use caution with ultra-sound near growth plates.
d. Athletic Activity During Rehabilitation
i. Must be pain-free the morning after activity.
ii. Avoid activities that interfere with doing the rehabilitation exercises.
iii. No participation if the weakened area is likely to cause further injury.
iv. Do not use modalities (e.g. ice) or analgesics that could mask pain
before an “at risk” activity.
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10. Rowland, T. W. Developmental Exercise Physiology. Champaign, IL: Human
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