July 2008
No. 44
Copyright
© 2008 AICE
No. 44
Copyright
© 2008 AICE
|
|
July 2008 No. 44 Copyright © 2008 AICE |
Even Toddlers Get It: Data 'Chunks' Are Easier to
Remember
Aggressive preschoolers found to have
fewer friends than others
Parents should limit young children's exposure to
background TV
Full-day kindergarteners' reading,
math gains fade by 3rd grade
School Superintendents Reluctant To
Drug Test Teachers
Reading, math scores up for 4th and 8th graders,
federal report shows
High-Speed Broadband Access for All Kids:
Breaking through the Barriers
Immigrant youths explore identity in high
school
Children are naturally prone to be empathic and
moral
Children's physical activity drops from age 9 to 15, NIH study indicates
Which
is easier to remember: 4432879960 or 443-297-9960? The latter, of course.
Adults seem to know automatically, in fact, that long strings of numbers are
more easily recalled when divided into smaller "bite-sized chunks,"
which is why we break up our telephone and Social Security numbers in this way.
Now researchers at The Johns Hopkins University have discovered that children as young as 14 months old can -- and do -- use the same technique to increase their working memories, indicating that "chunking" information in this way is not a learned strategy, but is, instead, a fundamental aspect of the human mind.
"Our work offers evidence of memory expansion based on conceptual knowledge
in untrained, preverbal subjects," said Lisa Feigenson, assistant
professor of psychological and brain sciences in the university's Krieger
School of Arts and Sciences, who worked on the study with colleague Justin
Halberda. "What we have basically done is show that very young children,
who can usually only keep track of about three objects at once, can keep track
of more if they use the kind of conceptual, linguistic, perceptual and spatial
cues adults also use."
In the team's experiment, the 14-month-olds were shown four toys which were
then hidden in a box. The children then were allowed to search for the missing
toys. Sometimes, two of the four toys were secretly withheld in another place.
The researchers observed how long the youngsters continued to search the box,
the idea being that they would search longer if they remembered there were more
toys yet to be found.
The researchers found the children would search longer when the four toys
consisted of two groups of two familiar objects, cats and cars, and one of each
type had been withheld. That indicated that the youngsters were using mental
chunking as a way to recall more items at a time.
The team also found that 14-month-olds can use spatial grouping cues (the
researchers grouped six identical orange balls in three groups of two before
hiding them) to expand memory, in the same way that adults group digits when
remembering phone numbers. When provided with such cues, the little ones could
remember up to six objects.
These results suggest that memory is not merely a passive storage system that
makes a "carbon copy" of our experiences. Instead, Feigenson says,
the results show that from at least early toddlerhood onward, memory is
constantly being restructured and reorganized to maximize its efficiency. The
researchers' results may have implications for educational strategies or for
helping those who suffer short-term memory problems. But more directly, they
show that the memory systems of young infants are surprisingly similar to those
of adults.
An
article on this research appears in the July 14 issue of the Proceedings of the
National Academy of Sciences, available online here: http://www.pnas.org
Preschoolers
who are aggressive, angry, and inattentive tend to have fewer playmates than
their non-aggressive classmates, whether they are boys or girls. In comparison,
non-aggressive children do better at interactions with many peers over time.
Those
are the findings of new research that used an important innovation for studying
children's peer relationships. Conducted by researchers at Arizona State
University and published in the July/August 2008 issue of the journal Child Development, the study suggests that
as early as preschool, aggressive children have less consistent relationships
with their peers.
Preschool
is a time when there are a lot of changes in the ways children interact with
their peers. Although aggressive behavior is common at this age, as children
practice social skills and learn how to control their behavior, some children
show more intense aggression or do so more often. These children may harm other
children, be quick to anger, and have trouble focusing on activities. Because
these children are at risk for later social and developmental problems,
researchers feel it is important to understand their early relationships with
peers.
The
Arizona State University researchers observed 97 students in six preschool
classrooms in an urban southwest area of the United States; the students'
teachers also reported on the children's behavior. Using a new quantitative
procedure called the Q-connectivity method, they repeatedly assessed the
children's peer interactions to determine how many peers the children
interacted with and how often those interactions took place. Using that
information, they looked at the relationship between children's ability to
establish and maintain relationships with peers and their tendency to display
physical aggression, anger, and attention problems.
Aggressive,
angry, and inattentive children tended to play with fewer peers repeatedly over
time than their non-aggressive classmates, who were more successful at
interacting frequently with many classmates over time. This pattern also was
true of younger children, which is not surprising given the typical social
development of younger children, who tend to move from solitary play to
increased involvement with classmates. The findings were the same for boys as
well as girls.
Despite
the fact that pediatricians recommend no screen media exposure for children
under age 2, three-quarters of very young children in America live in homes where
the television is on most of the time, according to research. A new study has
found that leaving your TV set on disrupts young children while they are
playing, even if the channel is tuned to adult shows. This means that simply
having the TV on, even in the background, may be detrimental to children's
development.
The
study, conducted by researchers at the University of Massachusetts, is
published in the July/August 2008 issue of the journal Child Development.
The
researchers looked at 50 children ages 1, 2, and 3. Each child came to a lab
with a parent and was invited to play for an hour with a variety of
age-appropriate toys. For half the time, a television was on in the room,
showing an episode of the adult game show Jeopardy!, with commercials; during
the other half hour, the TV was turned off.
Researchers
observed the children as they played to determine whether background TV—defined
as adult-oriented television that is on and may be watched by older members of
the family, but which very young children don't understand and to which they
pay little attention—affected the children's behavior during play.
Background
TV was found to disrupt the toy play of the children at every age, even when
they paid little attention to it. When the television was on, the children
played for significantly shorter periods of time and the time they spent
focused on their play was shorter, compared to when the TV was off.
"Background
TV, as an ever-changing audiovisual distractor, disrupts children's efforts to
sustain attention to ongoing play behaviors," according to Marie Evans
Schmidt, who is now a research associate at the Center on Media and Child
Health at Children's Hospital Boston and is the lead author of the study.
"Background TV is potentially a chronic environmental risk factor
affecting most American children. Parents should limit their young children's
exposure to background television."
Due
in part to poverty, home environment
Children
in full-day kindergarten have slightly better reading and math skills than
children in part-day kindergarten, but these initial academic benefits diminish
soon after the children leave kindergarten. This loss is due, in part, to
issues related to poverty and the quality of children's home environments.
Those
are the findings from a new study by researchers at the University of
Pittsburgh and Loyola University Chicago. Published in the July/August 2008
issue of the journal Child Development, the study sheds light on policy
discussions as full-day kindergarten programs become increasingly common in the
United States.
Using
data on 13,776 children from the Early Childhood Longitudinal
Study—Kindergarten Class of 1998-1999, a study of a nationally representative
group of kindergartners, the researchers measured children's academic
achievement in math and reading in the fall and spring of their kindergarten
and first-grade years, and in the spring of their third- and fifth-grade years.
The researchers also looked at the type and extent of child care the children
received outside of kindergarten, the quality of cognitive stimulation the
children received at home, and the poverty level of the children's families.
Overall,
the study found that the reading and math skills of children in full-day
kindergarten grew faster from the fall to the spring of their kindergarten
year, compared to the academic skills of children in part-day kindergarten.
However,
the study also found that the full-day kindergarteners' gains in reading and
math did not last far beyond the kindergarten year. In fact, from the spring of
their kindergarten year through fifth grade, the academic skills of children in
part-day kindergarten grew faster than those of children in full-day
kindergarten, with the advantage of full-day versus part-day programs fading by
the spring of third grade. The fade-out can be explained, in part, by the fact
that the children in part-day kindergarten were less poor and had more
stimulating home environments than those in full-day programs, according to the
study.
"The
results of this study suggest that the shift from part-day to full-day
kindergarten programs occurring across the U.S. may have positive implications
for students' learning trajectories in the short run," notes Elizabeth
Votruba-Drzal, assistant professor of psychology at the University of
Pittsburgh and the study's lead author. "They also highlight that
characteristics of children and their families play noteworthy roles in why the
full-day advantages fade relatively quickly."
School
superintendents are reluctant to drug test teachers, even though most believe
student safety outweighs a teacher’s right to privacy when it comes to drug
testing, according to new research from the University of New Hampshire.
The
research is presented in the June 2008 issue of Teachers College Record in the article “To Test
or Not To Test? Drug Testing Teachers: The View of the Superintendent.” The
lead author is Todd DeMitchell, professor of education at UNH. Co-authors are
Stephen Kossakoski, assistant superintendent with Supervisory Administrative
Unit #16, Exeter, N.H.; and Tony Baldasaro, doctoral student of education at
UNH and a school district improvement administrator with Supervisory
Administrative Unit #16, Exeter.
The
researchers queried 500 superintendents nationally; of those, 144 responded.
The researchers sought information on the following issues:
• Have school
districts adopted a mandatory drug testing policy, either preemployment or
random, for teachers?
• Do superintendents support a mandatory drug
testing, either preemployment or random, for teachers?
• Do
superintendents have different support for preemployment and random drug
testing policies for teachers?
According
to DeMitchell, the researchers found that superintendents believe they have the
authority, without offending the Constitution, to implement teacher
preemployment and random drug-testing policies. However, in large part, they
are not implementing such policies.
“The
superintendents have a greater comfort level with preemployment testing than
random drug testing of teachers. Most superintendents believed that the drug
problem among teachers was not large enough to warrant action, but many
reserved the right to revisit the implementation of such policies if the
circumstances in their school district changed,” DeMitchell said.
The
key research findings include:
•
85 percent of superintendents do not believe drugs are a problem with their
educators.
• 22 percent believe drug testing teachers is an effective
means for combating drugs in schools.
• 70 percent agree that student
safety outweighs a teacher’s right to privacy in drug testing.
• 48
percent believe teachers have a diminished expectation of privacy because they
work with students.
• 71 percent believe that teachers hold
“safety-sensitive” positions – a momentary lapse in judgment can have
disastrous consequences.
• 48 percent support mandatory preemployment
drug testing for teachers; 73 percent believing that such policies do not
violate the constitutional rights of teachers.
• 35 percent support
random drug testing of currently employed teachers; 59 percent believe random
drug testing does not violate the constitutional rights of teachers.
DeMitchell
said there are several reasons why superintendents prefer preemployment drug
testing to random testing of current teachers.
Superintendents
perceive that random drug testing is more invasive of potential rights. In
addition, they believe that the ongoing monitoring of a random drug testing
program may be more cumbersome and costly than preemployment testing. Finally,
the superintendents, who largely came from small school districts where they
know the employees, may find it difficult to subject their colleagues to the
indignity of urinating into a cup.
“It
is easier to subject the unknown person to drug testing than to subject that
same person to drug testing once he or she has become ‘one of us.’ Because most
superintendents did not believe that there was a drug problem with their
current professional employees, there was no sense in disturbing the status
quo,” DeMitchell said.
Building
on the Basics:
The
Impact of High-Stakes Testing on Student Proficiency in Low- Stakes Subjects
School
systems across the nation have adopted policies that reward or sanction
particular schools on the basis of their students’ performance on standardized
math and reading tests. One of the most frequently raised concerns regarding
such “high-stakes testing” policies is that they oblige schools to focus on
subjects for which they are held accountable but to neglect the rest. Many have
worried that the limited focus of these policies could have an unintended
negative effect on student proficiency in other subjects, such as science, that
are important to the development of human capital and thus to future economic
growth.
This
paper uses a regression discontinuity design utilizing student-level data to
evaluate the impact of sanctions under Florida’s high-stakes testing policy on
student proficiency in science. Under that state’s A+ program, every public
school receives a letter grade from A to F that is based primarily upon its
students’ performance on the state’s standardized math and reading exams.
Students in Florida were also administered a standardized exam in science, but
this test was low-stakes because its results held no consequences under the A+
program or any other formal accountability policy.
Previous
research has found that the rewards and sanctions of receiving an F grade in
the prior year led to improved gains in student proficiency in the high-stakes
subjects of math and reading. This current paper is the first to evaluate the
impact of the incentives under this high-stakes testing system on student
proficiency in science. This paper adds to a sparse previous literature
quantitatively evaluating whether high-stakes testing policies have “crowded
out” learning in a low-stakes subject.
The
primary findings of the study are:
·
The
F-grade sanction produced after one year a gain in student science proficiency
of about a 0.08 standard deviation. These gains are similar to those in reading
and appear smaller than the gains in math that were due to the F sanction.
Full
paper:
http://www.manhattan-institute.org/html/cr_54.htm
Increases
seen in teen birth, low birth weight
The
nation's fourth and eighth graders scored higher in reading and mathematics
than they did during their last national assessment, according to the federal
government's latest annual statistical report on the well-being of the nation's
children. Not all the report's findings were positive; there also were
increases in the adolescent birth rate and the proportion of infants born at
low birthweight.
These
and other findings are described in America's Children in Brief: Key National
Indicators of Well-Being, 2008. The report is compiled by the Federal
Interagency Forum on Child and Family Statistics, a working group of Federal
agencies that collect, analyze, and report data on issues related to children
and families, with partners in private research organizations. It serves as a
report card on the status of the nation's children and youth, presenting
statistics compiled by a number of federal agencies in one convenient
reference.
"In
2007, scores of fourth and eighth graders were higher in mathematics than in
all previous assessments and higher in reading than in 2005," said Valena
Plisko, associate commissioner of the National Center for Education Statistics,
a part of the U.S. Department of Education.
This
year's report also saw an increase in low birthweight infants (less than 5
pounds 8 ounces). Low birthweight infants are at increased risk for infant
death and such lifelong disabilities as blindness, deafness and cerebral palsy.
"This
trend reflects an increase in the number of infants born prematurely, the
largest category of low birthweight infants," said Duane Alexander, M.D.,
director of the Eunice Kennedy Shriver National Institute of Child Health and
Human Development at the National Institutes of Health. Although not all the
reasons for the increase are known, infertility therapies, delayed childbearing
and an increase in multiple births may be contributing factors.
The
birth rate among adolescent girls ages 15 to 17 also increased, from 21 live
births for every 1,000 girls in 2005, to 22 per 1,000 in 2006. This was the
first increase in the past 15 years.
"It
is critical that we continue monitoring this trend carefully," said Edward
J. Sondik, PhD, director of the National Center for Health Statistics in the
Centers for Disease Control and Prevention. "Compared with other teens
their age, teen mothers are less likely to finish high school or to graduate
from college. Infants born to teen mothers are more likely to be of low
birthweight."
Among
the favorable changes in the report were a decline in childhood deaths from
injuries and a decrease in the percentage of eighth graders who smoked daily.
These
and other findings on the nation's children and youth are described in the
report's content areas:
Demographic
Background
http://extranet.nichd.nih.gov/childstats/childstats_release_070308.cfm#DemographicBackground
Family
and Social Environment
http://extranet.nichd.nih.gov/childstats/childstats_release_070308.cfm#FamilyandSocialEnvironment
Economic
Circumstances
http://extranet.nichd.nih.gov/childstats/childstats_release_070308.cfm#FamilyandSocialEnvironment
Health
Care
http://extranet.nichd.nih.gov/childstats/childstats_release_070308.cfm#HealthCare
Physical
Environment and Safety
http://extranet.nichd.nih.gov/childstats/childstats_release_070308.cfm#PhysicalEnvironmentandSafety
Education
http://extranet.nichd.nih.gov/childstats/childstats_release_070308.cfm#Education
Health
http://extranet.nichd.nih.gov/childstats/childstats_release_070308.cfm#Health
The
Web site at http://childstats.gov contains all data updates and detailed statistical information accompanying
this year's America's Children in Brief report. As in previous years, not all
statistics are collected on an annual basis and so some data in the Brief may
be unchanged from last year's report.
The State Educational Technology Directors
Association (SETDA), representing all 50 states and DC, has released the “High-Speed
Broadband Access for All Kids: Breaking through the Barriers” report to address
the growing concern and critical need for high-speed Internet access among our
districts and schools. Although national statistics boast almost 98%
connectivity in US schools, the substance and bandwidth of the connection is
often problematic and insufficient. High-speed broadband access and
connectivity are vital for economic growth, global competitiveness, education,
innovation, and creativity. Ensuring high-speed broadband access for all
students has become a critical national issue especially when considering the
necessity for the use of technology in assessment, accountability, engagement,
and preparing our students for work and life in the 21st century.
SETDA worked with stakeholders from all 50
states, education, and industry in developing the recommendations. This report
identifies the key issues facing the educational community relating to robust
connectivity and recommends how states and districts can successfully implement
high-speed broadband in their schools. The report also provides stakeholders
and policymakers with strategies and models for bringing this critical issue to
the national and state policy level.
Key recommendations include:
In a
technology-rich learning environment for the next 2-3 years, SETDA
recommends:
* An external Internet connection to the Internet Service
Provider of 10 Mbps per 1,000 students/staff
* Internal wide area
network connections from the district to each school between schools of at
least 100 Mbps per 1,000 students/staff
In a technology-rich learning environment
for the next 5-7 years, SETDA recommends:
* An external Internet
connection to the Internet Service Provider of 100 Mbps per 1,000
students/staff
* Internal wide area network connections from the
district to each school between schools of at least 1 Gbps per 1,000
students/staff
“Planning and implementing for this growth
is critical for our education system,” stated Mary Ann Wolf, PhD, SETDA’s
Executive Director. “We now have data that shows how technology makes a
significant impact on student achievement in all subject areas and grades – not
to mention providing unprecedented opportunities for on-going and sustainable
professional development that improves teacher practice within the classroom.
High speed broadband is essential to making change happen.”
Key issues include:
* Teachers and
students need high-speed broadband access in their schools to take advantage of
a wide range of new and rich educational tools and resources available for
learning anytime, anywhere
* Teachers need high-speed broadband access
for professional development, and engaging in professional learning communities
as well as accessing new educational resources such as curriculum cadres and
education portals
* Administrators need high-speed broadband access to
conduct online assessments and to access data for effective decision making
* Students need high-speed broadband access to overcome the digital
divide in rural and low socio-economic areas
You
can view the full report at http://www.setda.org/web/guest/class2020actionplan.
Children
from immigrant families are assumed to give up their families' ethnic and
cultural background in order to assimilate with American culture. But a new
study shows that in fact, they find ways to combine their cultural heritage
with their identification as members of American society, especially during the
high school years. The types of labels they create and use could foreshadow the
types of labels used by the larger society in the years to come.
The
study, conducted by researchers at the University of California, Los Angeles,
Wake Forest University, and Williamette University, appears in the July/August
2008 issue of the journal Child Development.
"Given
that immigrant families comprise the large majority of those with Asian and
Latin American backgrounds and that these are the two fastest rising ethnic
groups in the United States, the outcome of these explorations will have
implications for the nature of ethnic categories and ethnic identity in the
broader society," according to Andrew J. Fuligni, professor of psychiatry
and psychology at the University of California, Los Angeles, and the study's
lead author.
The
researchers studied about 380 adolescents from Asian and Latin American
immigrant families in Los Angeles over the course of four years of high school.
The youths chose from a long list of ethnic labels that included terms
referring to national origin (such as Mexican), pan-ethnic terms (such as
Asian), and terms including the word "American" (such as American or
Asian American). They study also assessed adolescents' degree of attachment to
their ethnic background, the amount of exploration they'd done of their
cultural heritage, and their proficiency in their families' native language.
Most
teenagers who grow up in immigrant families choose a hyphenated label (such as
Mexican-American) to describe themselves, according to the study. Moreover,
significant numbers of these adolescents change their labels from year to year,
suggesting that high school is a time for youths from immigrant families to
explore their identities.
The
study also found that first-generation teens (i.e., those who were born outside
the United States) were more likely to choose a national origin label (such as
Chinese) to describe themselves than were second-generation teens (i.e., those
who were born in America to foreign-born parents). Furthermore, teens reported
higher levels of ethnic attachment, exploration, and native language
proficiency during the years in which they selected a national origin label to
describe themselves than in other years.
Children
between the ages of seven and 12 appear to be naturally inclined to feel
empathy for others in pain, according to researchers at the University of
Chicago, who used functional Magnetic Resonance Imaging (fMRI) scans to study
responses in children.
The
responses on the scans were similar to those found in studies of adults.
Researchers found that children, like adults, show responses to pain in the
same areas of their brains. The research also found additional aspects of the
brain activated in children, when youngsters saw another person intentionally
hurt by another individual.
"This
study is the first to examine in young children both the neural response to
pain in others and the impact of someone causing pain to someone else,"
said Jean Decety, Professor in the Departments of Psychology and Psychiatry at
the University of Chicago, who reported the findings in the article, "Who
Caused the Pain? An fMRI Investigation of Empathy and Intentionality in Children,"
published in the currrent issue of Neuropsychologia. Joining him as
co-authors were University students Kalina Michalska and Yuko Aktsuki.
The
programming for empathy is something that is "hard-wired" into the
brains of normal children, and not entirely the product of parental guidance or
other nurturing, said Decety. Understanding the brain's role in responding to
pain can help researchers understand how brain impairments influence
anti-social behavior, such as bullying, he explained.
For
their research, the team showed 17 typically developed children, ages seven to
12, animated photos of people experiencing pain, either received accidentally
or inflicted intentionally. The group included nine girls and eight boys.
While
undergoing fMRI scans, children where shown animations using three photographs
of two people whose right hands or right feet only were visible.
The
photographs showed people in pain accidently caused, such as when a heavy bowl
was dropped on their hands, and situations in which the people were hurt, such
as when a person stepped intentionally on someone's foot. They were also shown
pictures without pain and animations in which people helped someone alleviate
pain.
The
scans showed that the parts of the brain activated when adults see pain were
also triggered in children.
"Consistent
with previous functional MRI studies of pain empathy with adults, the
perception of other people in pain in children was associated with increased
hemodymamic activity in the neural circuits involved in the processing of first-hand
experience of pain, including the insula, somatosensory cortex, anterior
midcigulate cortex, periaqueductal gray and supplementary motor area,"
Decety wrote.
However,
when the children saw animations of someone intentionally hurt, the regions of
the brain engaged in social interaction and moral reasoning (the
temporo-parietal junction, the paracigulate, orital medial frontal cortices and
amygdala) also were activated.
The
study, which was supported by the National Science Foundation, provides new
insights for children between childrens' perceptions of right and wrong and how
their brains process information, Decety said. "Although our study did not
tap into explicit moral judgment, perceiving an individual intentionally
harming another person is likely to elicit the awareness of moral wrongdoing in
the observer," he wrote.
Subsequent
interviews with the children showed they were aware of wrong-doing in the
animations in which someone was hurt. "Thirteen of the children thought
that the situations were unfair, and they asked about the reason that could
explain this behavior," Decety said.
By
15, most fail to reach recommended activity level
The
activity level of a large group of American children dropped sharply between
age 9 and age 15, when most failed to reach the daily recommended activity
level, according to the latest findings from a long-term study by the National
Institutes of Health.
The
analysis is one of the largest, most comprehensive of its kind to date.
The
researchers evaluated the children to determine whether they achieved the
minimum 60 minutes per day of moderate to vigorous physical activity (MVPA)
recommended for children.
At
age 9, the children averaged roughly three hours of MVPA on weekdays and
weekends. By age 15, however, they averaged only 40 minutes per weekday, and 35
minutes per weekend.
"Lack
of physical activity in childhood raises the risk for obesity and its attendant
health problems later in life," said Duane Alexander, M.D., Director of
NIH's Eunice Kennedy Shriver National Institute of Child Health and Human
Development (NICHD). "Helping American children maintain appropriate
activity levels is a major public health goal requiring immediate action."
The
analysis was conducted on data collected for the NICHD Study of Early Child
Care and Youth Development, a long term study of more than 1,000 children from
ethnically and economically diverse backgrounds. The study collected
information on various other aspects of children's health and development. It
was geared toward gathering information on children's experience in various
child care arrangements but did not constitute a nationally representative
sample of the United States as a whole.
The
analysis, appears in the July 16 Journal of the American Medical Association.
Philip R. Nader, M.D., of the University of California San Diego, La Jolla, and
colleagues collected physical activity data on 1,032 children when they were 9
years old until they were age 15. Physical activity was measured by the
children wearing an accelerometer, a monitor worn on a belt that records
minute-by-minute movement counts. The children would wear this monitor for one
week a year at ages 9,11,12 and 15. The study took place in 10 geographic
locations from 2000-2006. Participants included boys (517 [50.1 percent]) and
girls (515 [49.9 percent]); 76.6 percent white (n = 791); and 24.5 percent (n =
231) lived in low-income families.
The
researchers found that both the average minutes of MVPA and the range of
minutes spent in MVPA decreased as children moved into adolescence. At 9 years,
children engaged in MVPA approximately 3 hours per day on both weekdays and
weekends. By 15 years, adolescents were only engaging in MVPA for 49 minutes
per weekday and 35 minutes per weekend day. At 9 and 11 years, almost all
children met the guidelines (of 60 minutes of MVPA per day), but by 15 years,
only 31 percent and 17 percent met guidelines on weekdays and weekends,
respectively. Both weekday and weekend MVPA showed significant decreases in
MVPA between 9 and 15 years, with decreases of 38 and 41 minutes per year,
respectively.
The
estimated age at which girls crossed below the recommended 60 minutes of MVPA
per day was approximately 13.1 years for weekday activity compared with boys at
14.7 years, and for weekend activity, girls crossed below the recommended 60
minutes of MVPA at 12.6 years compared with boys at 13.4 years.
"More
research is … needed to understand the reasons for such substantial decreases
in youth activity. Further study and more precise descriptions of the immediate
activity environment, such as whether youth are located in urban, suburban, or
rural areas; availability of safe places to be active; and quality of school-based
physical education may explain some of the individual and regional differences
noted in this and other studies."
The
2005 Dietary Guidelines for Americans recommends that children and adolescents
engage in at least 60 minutes of physical activity on most, preferably all,
days of the week. (See http://www.health.gov/dietaryguidelines/dga2005/document/default.htm.)
As
examples of moderate physical activity, the Centers for Disease Control and
Prevention list walking briskly, dancing, swimming, or bicycling on level
terrain. Vigorous physical activity includes such activities as jogging,
high-impact aerobic dancing, swimming continuous laps, or bicycling uphill.
Additional information is available at http://www.cdc.gov/nccdphp/dnpa/physical/everyone/recommendations/children.htm
The
researchers found that, at ages 9 and 11, more than 90 percent of the children
met the recommended level of 60 minutes or more of MVPA each day. By age 15,
however, only 31 percent met the recommended level on weekdays, and 17 percent
met the recommended level on weekends. The researchers estimated that physical
activity declined by about 40 minutes per day each year until, by age 15, most
failed to reach the daily recommended activity level. On average, boys were
more active than girls, spending 18 more minutes per weekday in MVPA than did
girls, and 13 more minutes per day in MVPA on weekends. The researchers
estimated the age at which girls dropped below the recommended level of 60
minutes of MVPA as 13.1 years for weekdays, compared to boys, who dropped below
the recommended level at 14.7 years. For weekends, girls dropped below the
recommended level at 12.6 years, and boys at 13.4 years.
"This
decline augurs poorly for levels of physical activity in American adults and
potentially for health over the life-course," the study authors wrote.
"Consequently, there is need for program and policy action as early as
possible at the family, community, school, health care, and governmental levels
to address the problem of decreasing physical activity with increasing
age."
Dr.
Nader explained that local school systems have a role to play, by ensuring
children receive periodic recess breaks and daily active physical education.