Chapter 11: Physical Development in Middle Childhood
What strategies can be applied to foster healthy lifestyles in school-age children?
Increase health-related knowledge and encourage healthy behaviors Involve parents in supporting health education Provide healthy environments in schools Make voluntary screening for risk factors available as part of heath education Promote pleasurable physical activity Teach children to be critical of media advertising Work for safer, healthier community environments for children
How common are unintentional injuries and fatalities in middle childhood? How can they vary?
Injury fatalities increase from middle childhood into adolescence, and rates for boys rise above those for girls. Poverty and rural or inner-city residence are associated with dangerous environments and reduced parental monitoring; are also linked to high injury rates
Why is care of teeth so essential in middle childhood?
It affects the child's appearance, speech, and ability to chew properly. More than 50% of US school-age children have at least some tooth age, especially left untreated in low-SES kids. As decay continues, they have pain, embarrassment, distraction from play/learning, and absences
What positive impact does participation in adult-organized youth sports have in middle childhood?
Joining community athletic teams generally is related to increased self esteem and social skills. For shy children, sports participation plays a protective role, fostering self-confidence and decreasing social anxiety. Children who view themselves as good at sports are more likely to continue playing on teams in adolescence, predicting greater sports participation and physical fitness activities in adulthood
What four basic motor capacities are gained in middle childhood?
1) Flexibility- physically more pliable and elastic 2) Balance- supports running, hopping, skipping, throwing, kicking, etc. 3) Agility- quicker and more accurate movements, like in dance, tag, soccer 4) Force- throwing and kicking higher or jumping higher off the ground
What different factors contribute to childhood obesity (8)?
1) Heredity- more common w/ 1+ obese parents 2) Socioeconomic status- more common if low 3) Early growth pattern- more common w/ infants who gain weight rapidly 4) Family eating habits- more common if parents purchase junk food, use them as rewards, anxious overfeed, or control children's intake 5) Responsiveness to food cues- more common if children decide when to eat based on taste, smell, sight, time of day rather than hunger 6) Physical activity- more common if less physically active and w/ insufficient sleep 7) Television viewing- more common w/ many hours spent watching television 8) Early malnutrition- more common w/ early severe malnutrition -> growth stunting b/c malnutrition disrupts appetite control centers in the brain so children overeat w/ plentiful food
What two main ways does prolonged malnutrition affect learning and behavior in middle childhood?
1) Sharper heart rate and greater cortisol levels in saliva are associated with greater stress reactivity 2) Deficient diet alters production of neurotransmitters in the brain
How frequent are chronic illnesses in school-age children? What is most common?
20-25% of US children living at home have chronic diseases/conditions (including physical disabilities). The most common (1/3 of such illnesses) and the most frequent cause of school absence/childhood hospitalization is asthma. Prevalence (10% of children) is at its highest level, increasing the past several decades. Boys, African-American children, children born underweight, children with smoking parents, and children living in poverty are at greatest risk (maybe due to pollution for the latter group). Obesity involves high levels of blood-circulating inflammatory substances associated with body fat and pressure of excess weight on chest wall, also contributing to prevalence of asthma
How does overweight vary with age?
23% of preschoolers to 35% of school-age children/adolescents to 69% of adults are overweight. Overweight preschoolers are more likely to be overweight later while few young people persistently overweight in adolescence attain normal weight in adulthood
How do mandates for recess and physical education in schools vary across the US?
80% of school districts no longer require daily recess for elementary school students in an effort to translate more time for academic achievement Similarly, although most US states require some PE, only 6 require it in every grade. Nearly half of US elementary and secondary school students do not attend any PE classes during a typical school week. As a result, fewer than 1/3 of 6-17 year olds engage in at least moderate-intensity activity for 60 minutes per day
How does poverty continue to be a powerful predictor of poor health in middle childhood?
Economically disadvantaged US children often lack health insurance or, if publicly insured, receive lower quality care. Many don't have regular access to a doctor, and many lack basic necessities like a comfortable home/regular meals
What role do games with rules, which become more common in middle childhood, play?
Gains in perspective taking, i.e. understanding roles of several players in a game, explain more structure in games and in turn contribute to emotional and social development. Child-invented games usually rely on simple physical skills and luck, so they become contests of individual ability. Children try out different styles of cooperating competing, losing, and winning with little personal risk. In organizing a game, children discover why rules are necessary and which ones work well, like the ones that optimize fairness
What factors explain individual differences in motor skills?
Generally, motor skills are influenced by both heredity and environment Body build: taller, more muscular children excel at many motor tasks Parents: children w/ parents who encourage physical exercise enjoy it more and are more skilled Family income: limits cildren's access to lessons to develop abilities like ballet, tennis, music, gymnastics. For low SES children, school and community provisions for nurturing motor skills are crucial Sex: differences more pronounced in middle childhood. Girls have an edge in fine-motor skills of handwriting/drawing and in gross-motor skills depending on balance and agility. Boys outperform on other skills especially throwing and kicking. It doesn't just have to do with muscle mass, but also social environment (parents hold higher expectations for boys' athletic performance). The more strongly girls believe females are incompetent at sports, the lower they judge their own ability and the poorer they actually perform, but girls and older school-age children regard boys' advantage in sports as unjust
What interventions foster positive family relationships to help parent(s) and child cope with their severe chronic illness and improve adjustment?
Health education (learn about illness and treatment) Home visits by health professionals (offer counseling and social support) Schools that accommodate children's special health/education needs Disease-specific summer camps (teach self-help skills and give parents time off) Parent and peer support group
What reasons explain the gap between knowledge and practice for school-age children on health information?
Health is not a very important goal for children who feel good most of the time. Children do not yet have an adult-like perspective to relate past, present, and future. Much health information given to children is contradicted by other sources (TV, peers, adults)
What factors explain variations in occurrence of nearsightedness?
Heredity- greater chance w/ myopic parents Race- occurs more frequently in Asian than Caucasian populations Early biological trauma- low birth weight school-age children have high rate due to immaturity of visual structures, slower eye growth, and greater incidence of eye disease Vision behaviors- avoiding reading in dim light and sitting too close to the TV/computer screen; more time spent reading, writing, using computer, more likely children are to be myopic
How can changes in rates of illness be explained across middle childhood?
Higher rate of illness in the first two years of elementary school than later is due to exposure to sick children and a still developing immune system. This leads to children missing 1-5 days of school per year
What kinds of children remain susceptible to injury in middle childhood?
Highly active, impulsive children, many of whom are boys, remain susceptible to injury. They may have just as much safety knowledge but are less likely to implement it. Boys judge risky play activities as less likely to result in injury than girls, and they pay less attention to injury risk cues like fearful/hesitant peers Children may also resist efforts to increase safety if parents do not act as safety-conscious models, rarely supervise children's activities, or use punitive/inconsistent discipline to enforce rules
What is asthma caused by?
Highly sensitive bronchial tubes in response to cold weather, infection, exercise, allergies, emotional stress -> mucus and contraction of bronchial tubes -> coughing, breathing difficulty
How do adult-organized youth sports tackle safety?
Most organized youth sports have health and safety rules to limit injuries. However, football has a high incidence of serious injury. 8-12 y/o boys in tackle football leagues experience rates of concussion (brain injuries due to blow to the head or body) that equal those of high school and college players In any sport, frequent, intense practice can lead to painful "overuse" injuries that, in extremes, cause stress-related fractures resulting in impaired physical growth
What is the leading cause of injury in middle childhood? How can this be addressed?
Motor vehicle accidents involving children as passengers or pedestrians (midblock dart-outs, bicycle accidents from disobeying traffic signals). Young children fail to think before they act with many stimuli impinging them at once. Children need frequent reminders, supervision, and prohibitions against venturing into busy traffic on their own. (However, children are unsupervised 35% of the time) School- and community-based prevention programs use extensive modeling and rehearsal of safety practices. It is better to target specific injury risks rather than many risks at once (avoid overstimulation) Legal requirement for children to wear helmets while bicycling, in-line skating, skateboarding, or using scooters leads to 9% reduction in head injuries, leading cause of permanent physical disability and death in school-age children
What is the most common vision problem in middle childhood? What is unique about this condition compared to other health complications?
Myopia or nearsightedness, affecting about 25% of kids (this rate rises to 60% by early adulthood) Unlike other health complicatoins, incidence of myopia increases with SES
How do neurotransmitters change brain function over the course of middle childhood?
Neurons become more selective in their response to neurotransmitters, making children more effective in thinking. This is related to cognitive performance, social/emotional adjustment, and ability to withstand stress
What is malocclusion?
A condition in which the upper and lower teeth do not meet properly; occurs in one third of school age children; 14% of cases have serious difficulty biting and chewing. It can be caused by thumb sucking and crowding of permanent teeth. The problem clears as the jaw grows
What is nocturnal enuresis caused by?
A failure of muscular responses that inhibit urination or a hormonal imbalance that permits too much urine to accumulate during the night can cause enuresis. Some children also have difficulty awakening to the sensation of a full bladder Punishing school-age child for wetting only makes matters worse
What is obesity?
A greater than 20 percent increase over healthy weight, based on body mass index (BMI), a ratio of weight to height associated with body fat. A BMI above 85% is overweight and BMI above 95% is obese
What trends in obesity have occurred worldwide?
A rise in overweight and obesity has occurred in many Western/industrialized nations (though smaller in Scandinavia/Netherlands). In US, 32% of kids are overweight and 17% obese. In developing countries, as urbanization shifts the popular to sedentary lifestyles and diets high in meats and energy-dense refined foods, obesity rates have risen
What is dominance hierarchy?
A stable ordering of group members that predicts who will win when conflict arises; created by rough-and-tumble play in children. Once established, hostility is rare, as play-fighting is a safe context to assess the strength of a peer before challenging that peer's dominance
What are more severe chronic illnesses school-age children in the US are afflicted by? In what ways can these affect children's lives?
About 2% of US children have severe chronic illnesses like sickle cell anemia, cystic fibrosis, diabetes, arthritis, cancer, and AIDS Painful medical treatments, physical discomfort, and changes in appearance disrupt daily lie, making concentration at school difficult and separating children from peers. It also increases family and child stress. Thus, chronically ill children are at risk for academic, emotional, and social difficulties; more likely to suffer from low self-esteem, depression, smoking habits, illegal drug use, and suicidal thoughts at adolescence
How does prevalence of participation in adult-organized youth sports vary among school-age children?
About half of US children (60% boys, 37% girls) participate in organized sports outside of school hours b/w ages 5-18. Children in low SES communities are profoundly under-served with girls and ethnic minorities having especially limited opportunities
How do hormones change brain function over the course of middle childhood?
Age 7-8, an increase in androgens (in both sexes, but in males in adolescence) occurs, and they affect brain organization and behavior
In what way do teeth fall in children aged 6 to 12?
All 20 primary teeth are lost and replaced by permanent ones. Girls lose teeth slightly earlier than boys. Lower teeth go before upper teeth. Permanent teeth seem large until facial bones in the jaw and chin grow
What factors play a role in improved motor performance in middle childhood?
Along with body growth, more efficient information processing, like more rapid response to relevant stimuli and greater anticipation to repeated stimuli This is why 5-7 year olds play T-ball rather than baseball and handball, four-square, and kickball over tennis, basketball and football
Why do children have unusual flexibility of movement and greater desire for physical exercise?
Along with increasing muscle strength, their bones lengthen and broaden, but their ligaments are not yet firmly attached to bones. This subsides as bones strengthen to accommodate physical activity and muscles adapt to enlarging skeleton. Also, growth in lung size permits more air exchange per breath, so children can better exercise vigorously without tiring
How can organized sports in middle childhood be developmentally appropriate?
Builds on children's interests Teach age-appropriate skills Emphasize enjoyment Emphasize effort, improvement, participation, and teamwork Limit frequency and length of practices Focus on personal and team improvement Discourage unhealthy competition Permit children to contribute to rules and strategies
How common is nocturnal enuresis?
Bedwetting during the night occurs in 10% of US school-age children. More boys than girls are affected. Heredity is a major contributor.
What is the most effective way to encourage exercise in obese children?
Best approaches help obese children set personal exercise goals and keep a record of success in meeting those goals. They should be reinforced to spend less time inactive, like rewards (tickets to zoo) to increase liking of physical activity. This increases children's sense of personal control over exercising
What is the most effective way to treat obesity?
Best interventions are family-based and focus on changing behaviors, like revising eating patterns, encourage daily exercise, and reinforce praise. The more weight parents loss, the more their children lost. Follow-ups showed children maintained their weight loss more effectively than adults (so important to intervene at earlier age)
How does physical growth vary between boys and girls?
Between ages 6-8, girls are slightly shorter and lighter than boys. By age 9, the trend reverses. Also, as in early childhood, girls have slightly more body fat and boys more muscle, and at age 8, girls accumulate fat at a faster rate
How are obese children received by society?
Both children and adults rate obese youngsters as unlikable and stereotype them as lazy, sloppy, dirty, ugly, stupid, and deceitful In school, obese children/adolescents are often socially isolated with higher peer teasing, rejection and consequent low self-esteem They also tend to achieve less well than healthy-weight agemates Since unhappiness and overeating contribute to each other, obesity from childhood persists and can predict serious behavioral problems (defiance, aggression, severe depression, suicidal thoughts and behavior)
What accounts for the vast differences in physical size across the world?
Both heredity and environment: -Body size sometimes reflects evolutionary adaptation to a particular climate (long, learn in hot tropics and short, stock in cold Arctic) -Children who grow tallest usually live in developed countries where food is plentiful and infectious diseases are controlled
How does brain weight, white matter volume, and grey matter volume change in middle childhood?
Brain weight increases only 10% in middle childhood and adolescence. However, white matter rises steadily, especially in prefrontal cortex, parietal lobes, and corpus callosum, overall improving executive function. Also, as children acquire more complex abilities, synaptic connections increase between stimulated neurons. Thus, grey matter peaks in middle childhood and declines with synaptic pruning
What are secular trends in physical growth?
Changes in body size from one generation to the next; occur in industrialized nations. Today's children are larger compared to their parents and grandparents in their youth due to faster rate of physical development. As developing nations make socioeconomic progress, they also show secular gains due to improved health and nutrition. Secular gains are smaller for low-income children due to poorer diets and greater frequency of growth-stunting illnesses
What are the effects of increase in grey and white matter in the brain in middle childhood?
Children gain in executive function (coordinating integrated functions of various areas for more complex and adaptive behavior) including sustained attention, inhibition, working memory capacity, and organized, flexible thinking
What effect do more nutritious meals have on children aged 6-11?
Children report feeling better and focusing better after eating healthy food and feel sluggish after eating junk food A diet high in sugar, fat, and processed foot in early childhood predicted slightly lower IQ age 8 Insufficient iron and folate in diet are related to poorer concentration and mental test performance
How much do children on average grow from 6 to 11 years old in North America?
Children weigh about 45 pounds and are 3 1/2 feet tall. They add 2-3 inches in height and 5 pounds in weight each year
What effect does prolonged malnutrition have in middle childhood?
Delay in physical growth, impaired motor coordination, inattention, low IQ and worse learning/behavior due to prolonged malnutrition are evident in middle childhood and intensify with new academic and social challenges at school
How can nocturnal enuresis be treated?
Doctors prescribe synthetic hormone called desmopressin which reduces the amount of urine produced (short-term solution) However, most effective treatment is a urine alarm that wakes the child at the first sign of dampness and conditions the child to wake up It can be outgrown without intervention, though this generally takes years
Why do obese children have difficulty receiving treatment?
One study shows only 1/4 of overweight parents judged their overweight children to have a weight problem. Although many try to slim down in adolescence, they often go on crash diets that makes things worse. Temporary starvation leads to physical stress, discomfort, and fatigue, and the children returns to old eating patterns as their body begins burning calories more slowly to resist future weight loss
Why do children spend less time gathering informally on sidewalks and in playgrounds?
Parents are more concerned about neighborhood safety Children's time is being competed along with TV, video games, and the Internet Adult-organized sports like Little League baseball are on the rise However, this is not the case for village societies in developing countries and low-SES communities in industrialization nations, reflecting distinct cultural values
What is the biggest barrier to healthy eating for children?
Ready availability of unhealthy options, even in their homes In fact, readily available, healthy between-meal snacks (ceese, fruit, raw veggies, peanut butter) can meet children's nutritional needs and increase their liking for healthy foods.
What difficulties present for obese children?
Serious emotional and social difficulties Risk for lifelong health problems (in yearly years, high blood pressure, high cholesterol levels, respiratory abnormalities, insulin resistance, inflammatory reactions -> heart disease, circulatory difficulties, type 2 diabetes, gallbladder disease, sleep and digestive disorders, cancers, early death) Increased frequency of diabetes, sometimes leading to early, severe complications (stroke, kidney failure, circulatory problems -> eventual blindness and leg amputation)
How can schools help in treatment of childhood obesity?
Serving healthier meals and ensuring regular physical activity, like limited vending machine access and additional recess or PE time In general, schools are best at providing long-term, comprehensive intervention
What is rough-and-tumble play?
Style of play characterized by friendly chasing and play-fighting; it emerges in preschool years and peaks in middle childhood (10% of free play). Children across many cultures engage in it with peers they like. It resembles social behavior of many other young mammals and originates in parents' physical play with babies. It is more common in boys due to prenatal exposure to androgens predisposing them to active play. It involves playful wrestling and hitting in boys and running and chasing with girls. Once children reach adolescence, rough-and-tumble is linked to aggression and teenagers unlike children "cheat" by hurting their opponent
What changes in hearing occur in middle childhood?
The Eustachian tube becomes longer, narrower, and more slanted, preventing fluid and bacteria from traveling so easily from mouth to ear. Thus, otitis media (middle ear infection) common in infancy/early childhood becomes less frequent. However, 3-4% of school-age children and 20% of low SES kids develop some hearing loss due to repeated infections
Which area of the body is growing fastest in middle childhood?
The lower portion of the body, i.e. they appear more long-legged
How do eating habits change as children enter middle childhood?
The proportion of children who eat meals with their families drops sharply between ages 9-14 (they've waned in general the past decades), even though eating an evening meal with parents is related to a diet higher in fruits, vegetables, grains, ad milk products (less soft drinks and fast foods)
In what ways are gains in fine-motor skill in middle childhood most evident?
Their gains are especially evident in their writing and drawing. By age 6, most children can print alphabet, first and last names, and numbers 1-10. Their writing however is large due to moving entire arm instead of just wrist and fingers. Legibility of writing increases as children produce more accurate letters with uniform height/spacing. Also, drawing shows dramatic gains in organization, detail, and representation of depth. At the end of preschool, children can copy 2-D shapes into their drawings. Around 9-10 y/o, 3-D is evident by overlapping objects, diagonal placement, and converging lines
What negative impact does participation in adult-organized youth sports have in middle childhood?
They are also known to overemphasize competition and substitute adult control for children's natural experimentation with rules and strategies. Coaches that make winning paramount make weaker performances associated with social ostracism, especially with boys. Children who join teams so early that necessary skills are beyond their abilities soon lose interest. Parents are even more influential than coaches. Those who value sports so highly they punish their child for making mistakes, insist child play after injury, hold child back in school to ensure physical advantage, or even seek medical interventions to improve child's performance are an extreme. This can set the stage for emotional difficulties and early athletic dropout, not elite performance
