Physical Development in Middle Childhood

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Physical Developmentin Middle Childhood

• Chapter 11

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BODY GROWTH

• Changes in Body Size and Proportions
• Children add about 2 to 3 inches in height and 5
  pounds in weight each year.
• Girls tend to have small growth spurts at ages
  41/2, 6 1/2, 81/2, and 10, boys slightly later
  at 4 1/2, 7, 9, and 10 1/2.
• Girls are slightly shorter and lighter than boys
  at ages 6 to 8, but by age 9 this trend is
  reversed.
• The lower portion of the body is growing fastest
  at this age period and children during this time
  appear long-legged.
• Girls have slightly more body fat and boys have
  more muscle. After age 8, girls begin
  accumulating fat at a faster rate.

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Worldwide Variations in Body Size

• Measurements of 8-year-olds living in many parts
  of the world reveal a 9-inch gap between the
  smallest and the largest youngsters.
• The shortest children tend to be found in South
  America, Asia, the Pacific Islands, and parts of
  Africa. The tallest children reside in Australia,
  northern and central Europe, and the United
  States.
• Both heredity and environment account for these
  differences in body size.

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Secular Trends in Physical Growth

• Secular trends in physical growth are changes in
  body size from one generation to the next. These
  have taken place in many industrialized nations.
• The larger size of modern children is mostly due
  to a faster rate of physical maturation.
• Improved health and nutrition play major roles in
  the secular trend.
• Although secular gain in height has slowed in
  recent decades, gain in weight is continuing at a
  high rate.

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Skeletal Growth

• During middle childhood, the bodys bones
  lengthen and broaden, but ligaments are not yet
  firmly attached to bones. Thus, children are
  granted unusual flexibility of movement.
• Between the ages of 6 and 12, all 20 primary
  teeth are replaced with permanent teeth.

• Care of the teeth is critical during the school
  years, since dental health affects the childs
  appearance, speech, and ability to chew properly.
• More than 50 percent of American school-age
  children have at least some tooth decay, and
  low-SES children have especially high levels.

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Skeletal Growth cont.

• Malocclusion is a condition in which the upper
  and lower teeth do not meet properly.
• Malocclusion can be caused by thumb sucking after
  permanent teeth come in, or by crowding of
  permanent teeth.

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Brain Development

• The frontal lobes of the cerebral cortex show a
  slight increase in surface area between ages 5
  and 7 due to continuing myelinization.
• The corpus callosum thickens, leading to improved
  communication between the two cortical
  hemispheres.
• Synaptic pruning continues, and lateralization of
  the cerebral hemispheres increases over the
  school years.

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Brain Development cont.

• Neurotransmitters are chemicals that permit
  neurons to communicate across synapses.
  Secretions of particular neurotransmitters are
  related to cognitive performance, social and
  emotional adjustment, and ability to withstand
  stress in children and adults.
• Brain functioning may also change because of an
  increase in androgens (male sex hormones) that
  occurs in both boys and girls around age 7 to 8.

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COMMON HEALTH PROBLEMS

• Good nutrition and rapid development of the
  bodys immune system work together to protect
  against disease.
• Poverty continues to be a powerful predictor of
  ill health during middle childhood.

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Vision and Hearing

• The most common vision problem in middle
  childhood is myopia, or nearsightedness.
• By the end of the school years, nearly 25 percent
  of children are affected.
• Myopia is affected by both heredity and
  experience.
• During middle childhood, the eustachian tube
  becomes longer, narrower, and more slanted as a
  result, otitis media (middle ear infection)
  becomes less frequent.

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Malnutrition

• School-age children need a well-balanced,
  plentiful diet to provide energy for successful
  learning in school and increased physical
  activity.
• Eating an evening meal with parents leads to
  healthier eating habits.
• Readily available, healthy between-meal snacks
  can help meet school-age childrens nutritional
  needs.

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Malnutrition cont.

• By middle childhood, the effects of prolonged and
  serious malnutrition are apparent in retarded
  physical growth, low intelligence test scores,
  poor motor coordination, inattention, and
  distractibility.
• Growth-stunted school-age children respond with
  greater fear to stressful situations.
• Animal evidence reveals that a deficient diet
  alters the production of neurotransmitters in the
  brain.
• When malnutrition persists for many years,
  permanent damage is done.

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Obesity

• Over 25 percent of American children suffer from
  obesity, a greater-than-20-percent increase over
  average body weight, based on the childs age,
  sex, and physical build.
• From 1980 to 2000, the rate of obesity in the
  American population climbed from 15 to 27
  percent. Obesity rates are also increasing
  rapidly in developing countries as urbanization
  shifts the population toward sedentary lifestyles
  and diets high in meats and refined foods.
• Over 80 percent of obese youngsters remain
  overweight as adults.

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Obesity
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Obesity cont.

• Causes of Obesity
• Fat children tend to have fat parents, and
  concordance for obesity is greater in identical
  than fraternal twins.
• Low-SES youngsters in industrialized nations are
  more likely to be overweight because of lack of
  knowledge about healthy diet a tendency to buy
  high-fat, low-cost foods and family stress.
• 6 percent of American low-SES children are growth
  stunted due to early malnutrition and are
  therefore at increased risk for obesity.

• Parental feeding practices contribute to
  childhood obesity.
• Research shows that obese children are more
  responsive to external stimuli associated with
  food and less responsive to internal hunger cues.
• Fat children are less physically active than
  their normal-weight peers.
• Recent evidence indicates that the rise in
  childhood obesity in the United States is in part
  due to television viewing.

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Obesity cont.

• Consequences of Obesity
• Both children and adults rate obese youngsters as
  unlikable.
• By middle childhood, obese children report
  feeling more depressed and display more behavior
  problems than normal-weight agemates.
• The psychological consequences of obesity combine
  with continuing discrimination to result in
  reduced life chances.

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Obesity cont.

• Treating Obesity
• Childhood obesity is difficult to treat because
  it is a family disorder.
• Crash diets deprive children of essential
  nutrients during a period of rapid growth, and
  can make matters worse.
• The most effective interventions are family based
  and focus on changing behaviors.

• Getting obese children to exercise is
  challenging, since they find being sedentary
  pleasurable.
• Positively reinforcing obese children for
  spending less time inactive is a successful
  technique.
• Schools can help reduce obesity by ensuring
  regular physical activity and serving healthier
  meals.

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Bed Wetting

• Nocturnal enuresis is bedwetting that occurs
  during the night.
• In most cases, it is caused by a failure of
  muscular responses that inhibit urination or a
  hormonal imbalance that permits too much urine to
  accumulate during the night.
• To treat enuresis, doctors often prescribe
  anti-depressant drugs, which reduce the amount of
  urine produced. This is a short-term solution
  once children stop taking it, they typically
  begin wetting again.
• The most effective treatment is a urine alarm
  that wakes the child at the first sign of
  dampness. It works according to conditioning
  principles.

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Illnesses

• Children experience a somewhat higher rate of
  illness during the first 2 years of elementary
  school than they will later on, due to exposure
  to sick children and the fact that their immune
  system is still developing.
• The most frequent cause of school absence and
  childhood hospitalization is asthma, a condition
  in which the bronchial tubes are highly
  sensitive.
• The number of children with asthma has more than
  doubled over the past thirty years.
• Boys, African-American children, and children who
  were born underweight, whose parents smoke, and
  who live in poverty are at greatest risk.

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Illnesses cont.

• About 2 percent of American children have chronic
  illnesses that are more severe than asthma, such
  as sickle cell anemia, cystic fibrosis, diabetes,
  arthritis, cancer, and AIDS.
• A strong link between parent psychological
  adjustment, good family functioning, and child
  well-being exists for chronically ill children,
  just as it does for physically healthy children.

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Unintentional Injuries

• The frequency of injuries increases steadily over
  middle childhood into adolescence, with boys
  showing a higher rate than girls.
• Motor vehicle and bicycle collisions account for
  most of the rise in injury incidence.
• As children spend more time away from parents and
  range further from home, safety education becomes
  more important.
• Wearing protective helmets is a vital safety
  intervention.
• The greatest risk takers tend to have parents who
  do not act as safety conscious models or who try
  to enforce rules by using punitive or
  inconsistent discipline.
• Highly active boys remain particularly
  susceptible to injury in middle childhood.

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Unintentional Injuries cont.
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Health Education

• The school-age period may be an important time
  for fostering healthy life-styles because of the
  childs growing independence, increasing
  cognitive capacities, and rapidly developing
  self-concept, which includes perceptions of
  physical well-being.

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• Health habits are slow to change.
• Health is not an important goal to children.
• Children do not yet have an adultlike time
  perspective, linking present preventive behaviors
  to future consequences.
• Health information is often contradicted by other
  sources, such as television advertising and the
  examples of adults and peers.

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• Information about health must be supplemented
  with reducing hazards, coaching children in good
  health practices, and modeling and reinforcing
  these behaviors.

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MOTOR DEVELOPMENT AND PLAY

• Gross Motor Development
• During middle childhood, running, jumping,
  hopping, and ball skills become more refined.
• Motor skills improve in the capacities of
  flexibility, balance, agility, and force.
• Steady improvements also occur in reaction
  time11-year-olds can respond almost twice as
  quickly to a stimulus as 5-year-olds.

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Fine Motor Development

• Fine motor development also improves steadily
  over the school years.
• Gains are especially evident in writing and
  drawing.
• Writing tends to be large at first, and
  legibility gradually increases.
• Drawings show gains in organization, detail, and
  representation of depth.
• School-age children not only depict objects in
  considerable detail, they also relate them to one
  another as part of an organized whole.

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Individual and Group Differences

• Parents who encourage physical exercise tend to
  have youngsters who enjoy it more and who are
  also more skilled.
• Family income affects childrens opportunities to
  develop a variety of physical abilities.
• Girls remain ahead in the fine motor area and
  skills such as skipping, jumping, and hopping,
  which depend on balance and agility.

• School-age boys genetic advantage in muscle mass
  is not great enough to account for their
  superiority in many gross motor skills thus,
  environment plays a large role in motor
  development.
• Greater emphasis on skill training for girls
  along with increased attention to their athletic
  achievements in schools and communities is likely
  to increase their involvement.

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Child-Organized Games

• Organized games with rules become common in
  middle childhood.
• Gains in perspective taking allow children to
  understand the roles of several players in a game
  and permit the transition to rule-oriented games.
• Participation in organized games helps children
  form more mature concepts of fairness and
  justice.

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Child-Organized Games cont.

• Adult-Organized Youth Sports
• The past several decades have witnessed a
  tremendous expansion of youth sports programs.
• Some researchers worry that adult-structured
  athletics are robbing children of crucial
  learning experiences and endangering their
  development.

• Children who join teams so early that the skills
  demanded are beyond their capabilities soon lose
  interest and drop out.
• Parents powerfully influence childrens athletic
  attitudes and capabilities.
• When coaches emphasize effort, improvement,
  participation, and teamwork, young athletes enjoy
  their experience more, like their coach and
  teammates more, and gain in self-esteem.

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Shadows of Our Evolutionary Past

• Rough-and-tumble play is the friendly wrestling,
  rolling, hitting, and chasing that children
  engage in.
• School-age youngsters are quite good at telling
  the difference between playful wrestling and a
  true aggressive attack.
• Girls rough-and-tumble play consists largely of
  running and chasing, whereas boys engage in more
  playful wrestling and hitting.
• A dominance hierarchy is a stable ordering of
  individuals that predicts who will win when
  conflict arises between group members.
• Once the hierarchy is established, it serves the
  adaptive function of limiting aggression among
  group members.

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Physical Education

• Physical education classes that provide regularly
  scheduled opportunities for exercise and play
  help ensure that all children have access to
  physical activity that supports
• healthy bodies.
• a sense of self-worth as physically active and
  capable beings.
• the cognitive and social skills necessary for
  getting along well with others.
• The average school-age child gets only 20 minutes
  of physical education a week.

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Physical Education

• Unfortunately, the growing fitness movement among
  adults has not filtered down to children
• Programs should emphasize informal games and
  individual exercisepursuits that are most likely
  to last into later years.
• Physically fit children become more active adults
  who reap many benefits.