Article

Age and Sex Differences in Physical Activity of Portuguese Adolescents

Faculty of Sports, University of Porto, Porto, Portugal.
Medicine & Science in Sports & Exercise (Impact Factor: 3.98). 02/2008; 40(1):65-70. DOI: 10.1249/mss.0b013e3181593e18
Source: PubMed
ABSTRACT
This study sought to examine sex- and age-associated variations in physical activity (PA) among Portuguese adolescents aged 10-18 yr.
A total of 12,577 males and females at the primary or secondary education level were sampled across four regions of Portugal. PA was assessed by a questionnaire, producing four different indexes: work/school (WSI), sport (SI), leisure time (LI), and total physical activity index (PAI). We examined sex and age differences by using two-way analysis of variance.
Males had higher mean values of PA than did females. In both sexes, mean values for all four PA indexes increased from ages 10 to 16 yr. After age 16, females decreased their mean values, whereas males continued to increase their values (except for LI). In both sexes, the average annual rate of change for the mean values of all four PA indexes correspond to three sensitive age periods (10-13, 13-16, and 16-18 yr). Until age 16, average mean changes for females ranged from +0.7 to +1.6% per year, except for SI in the youngest group (a modest decrease). For males under 16 yr, the pattern was similar, with increases ranging from 0.4 to 1.9% per year. After age 16, females experienced decreases of 1-2.1% per year for the four PA indexes, whereas males showed an increase for three indexes and an average decrease of 1.3% per year for LI.
These results suggest that it is important to consider sex differences in PA levels among Portuguese adolescents. Unlike their male counterparts, Portuguese females may reduce much of their PA during late adolescence.

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7
Age and Sex Differences in Physical Activity of
Portuguese Adolescents
ANDRE
´
FILIPE TEIXEIRA E SEABRA
1
, JOSE
´
ANTONIO RIBEIRO MAIA
1
, DENISA M. MENDONÇA
2
,
MARTINE THOMIS
3
, CARL J. CASPERSEN
4
, and JANET E. FULTON
5
1
Faculty of Sports,
2
Institute of Biomedical Sciences Abel Salazar, ICBAS, University of Porto, Porto, PORTUGAL;
3
Faculty
of Sport Sciences and Physical Education, Katholieke Universiteit Leuven, Leuven, BELGIUM;
4
Division of Diabetes
Translation, and
5
Division of Nutrition and Physical Activity, National Center for Chronic Disease Prevention and Health
Promotion, Centers for Disease Control and Prevention, Atlanta, GA
ABSTRACT
TEIXEIRA E SEABRA, A. F., J. A. R. MAIA, D. M. MENDONÇA, M. THOMIS, C. J. CASPERSEN, and J. E. FULTON. Age and
Sex Differences in Physical Activity of Portuguese Adolescents. Med. Sci. Sports Exerc., Vol. 40, No. 1, pp. 65–70, 2008. Purpose:
This study sought to examine sex- and age-associated variations in physical activity (PA) among Portuguese adolescents aged 10–18 yr.
Methods: A total of 12,577 males and females at the primary or secondary education level were sampled across four regions of
Portugal. PA was assessed by a questionnaire, producing four different indexes: work/school (WSI), sport (SI), leisure time (LI), and
total physical activity index (PAI). We examined sex and age differences by using two-way analysis of variance. Results: Males had
higher mean values of PA than did females. In both sexes, mean values for all four PA indexes increased from ages 10 to 16 yr.
After age 16, females decreased their mean values, whereas males continued to increase their values (except for LI). In both sexes,
the average annual rate of change for the mean values of all four PA indexes correspond to three sensitive age periods (10–13,
13–16, and 16–18 yr). Until age 16, average mean changes for females ranged from +0.7 to +1.6% per year, except for SI in the
youngest group (a modest decrease). For males under 16 yr, the pattern was similar, with increases ranging from 0.4 to 1.9% per
year. After age 16, females experienced decreases of 1–2.1% per year for the four PA indexes, whereas males showed an increase
for three indexes and an average decrease of 1.3% per year for LI. Conclusions: These results suggest that it is important to consider
sex differences in PA levels among Portuguese adolescents. Unlike their male counterparts, Portuguese females may reduce much of
their PA during late adolescence. Key Words: MOTOR ACTIVITY, SPORTS, DECLINE, CHILD
M
odern industrialized societies are witnessing an
increase in serious chronic diseases and morbid
conditions, such as diabetes (17) and obesity (9),
which are associated with the economic and health
burdens of cardiovascular disease for European countries
(16). An increase in these global epidemics seems to be
directly related to adverse behavioral patterns, such as
pursuing a sedentary lifestyle. The World Health Organ-
ization (30) has estimated that in developed and developing
countries around the world, 60–85% of people have
sedentary lifestyles.
Several scientific and medical institutions have deter-
mined a sedentary lifestyle to be one of the most serious
public health problems in modern societies, especially
because it affects a growing number of children and adoles-
cents (24,30). To achiev e health benefits, efforts to ensure
that adolescents participate in regular physical activity (PA)
of moderate to vigorous intensity are worth pursuing (22).
Recent years have seen a wealth of epidemiological
studies inv olving children and adolescents that have
examined the prevalence of PA by sex, age, race/ethnicity,
and socioeconomic status (1,5,7,14,23,25), as well as some
studies that have examined an array of characteristics
thought to explain the variation seen in PA levels and
patterns among adolescents (22). Several studies have
shown that males have greater levels of participation in
PA than do females (5,7,11,13,23,25,26) and that in the
United States and northern Europe, PA declines with
increasing age (7,23). No such data exist for southern
Europe or Mediterranean countries, particularly Portugal,
where important differences may exist in lifestyle behaviors
and in environmental, climatic, and geopolitical circum-
stances that may also influence school-based, sport, and
leisure-time PA. For example, throughout the country,
physical education is mandatory across all school levels,
and a sport school system exists that engages many students
during their free time. Another factor relates to the
infrastructure of Po rtuguese cities, with safe and large
sidewalks and parks providing ample opportunities for the
establishment of active and healthy lifestyles.
The aims of this cross-sectional study are to examine (1)
the age- and sex-specific PA patterns of Portuguese
Address for correspondence: Andre
´
Filipe Teixeira e Seabra, Ph.D., MPH,
Faculty of Sports, University of Porto, Portugal, Rua Dr. Pla
´
cido Costa,
91-4200 Porto, Portugal; E-mail: aseabra@fade.up.pt.
Submitted for publication March 2007.
Accepted for publication August 2007.
0195-9131/08/4001-0065/0
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Ò
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DOI: 10.1249/mss.0b013e3181593e18
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7
adolescents aged 10–18 yr, and (2) whether changes in PA
occur during potentially key developmental periods.
METHODS
Participa nts. For the 2003–2005 school years, we
sampled native Portuguese male and female students aged
10–18 yr. We selected students who were enrolled in public
and private schools from regions having 66 teachers
enrolled in the masters program of the Faculty of Sports
of the University of Porto. This sampling scheme was
necessary because these well-trained teachers were recruited
to oversee aspects of the study, and, most importantly, they
were responsible for the systematic administration of the
study questionnaires. As a result, these schools were located
in rural and urban areas in three regions nearest the city of
Porto (Porto, Vila Real, and Viseu) and one island-based
region (Regia
˜
o Auto
˜
noma Açores).
In Portugal, the majority of basic and secondary schools
comprise grades 5–12, which resulted in a total enrollment of
225,149 students from 364 schools in the four regions. We
sampled one class per grade from these schools to achieve a
good representation of students. Because the number of
students in any class in Portugal must not exceed 24 students
on average, that is the same number of students achieved per
classroom. Our school-based samples represented 18, 35, 18,
and 14%, respectively, of relevant schools found in the four
regions noted above. The final sample comprised 12,672
students, representing 4, 10, 6, and 10%, respectively, of all
available students by region. During the 2 yr of data
collection, questionnaires were administered between March
and June, to limit any effects of seasonal variation. The rate
of completing the physical activity questionnaire ranged
from 95 to 99.5% relative to class samples of students (N =
12,577). We should point out that whereas our sample
comprises Portuguese adolescents , it may not be fully
representative of all adolescents in Portugal. The project
was approved by the research committee of the Faculty of
Sport Sciences and Physical Education of the University of
Porto, and by school authorities. In addition, parents and
participating students provided informed conse nt. The
characteristics of the sampled students in terms of age and
sex are displayed in Table 1.
Physical activity. PA was estimated with the Baecke
et al. (4) questionnaire, which is considered a reliable and
valid instrument (19). This questionnaire has been shown to
be r el ia ble in diff ere nt sub sam p les of the Por tug ues e
population aged 10–18 yr, where intraclass correlation
estimates for PA have ranged from 0.80 to 0.87 (26).
Most of the Baecke questionnaire is made up of 16 items
that call for a Likert-type response (possibilities from 1 to 5)
and that are designed to assess diff erent categories of the
broad concept of PA (work/school, sport, and leisure). The
work index in the standard version of the Baecke
questionnaire is based on eight items intended to assess
different aspects of work activities of 20- to 32-yr-old
Dutch men and women (4). Because our study was
conducted in adolescent students, we reworded these
questions to reflect different aspects of their PA at school
that were independent of mandatory physical education
programs or school-based sport activities. We then calcu-
lated the work/school index (WSI) from eight equally
weighted items (questions 1–8). Items included asking
students how often at school they sat, stood, walked, lifted
heavy loads, sweated, and left school physically tired. They
were also asked to compare their school activity with that of
their peers. The sport index (SI) (questions 9–12) was
scored, in part, from the two most frequently played sports,
for which the number of hours per week, months per year,
and estimated intensity were reported. The SI also included
the frequency of overall participation in sport, the frequency
of sweating, and a subjective comparison of participation in
exercise relative to others one_s own age. The leisure-time
index (LI) (questions 13–16) summarized the freque ncy of
television viewing (which was negatively weighted),
cycling, and walking (which also included time spent
walking daily). The score of the three indexes varied from
1 to 5, and, when summed, the result was a total PA index
(PAI) whose score ranged from 3 to 15.
Training of teachers in study and questionnaire
procedures. Sixty-six teachers of physical education from
the selected regions participated in our study and were
responsible for administering the study question naires.
Participating teachers were 24 yr of age or older, and each
received8hoftraining,providedbytheprincipal
investigators. The training included an explanation of the
study objectives and its design, a reading and explanation of
each questionnaire and their associated instructions, and
suggestions of ways to address students_ questions or
diff icult ies that teac hers might en count er. Because t he
principal inves tigators emphasized the importance of having
complete questionnaires in the classroom setting, there
were, fortunately, no missing data.
Statistical analysis. Descriptive statistics summarized
the four PA indexes. Differences by sex across all age
groups for each index were tested with a factorial analysis
of variance. The Scheffe
´
test for multiple comparisons was
used to check for specific differences by age and sex. For
each of the four indexes, the average annual rate of change
TABLE 1. Frequency distribution of sample of Portuguese adolescent students, by age
and sex, 2003–2005.
Age (yr) Females, N (%) Males, N (%) Total, N (%)
10 396 (6.1) 353 (5.8) 749 (5.9)
11 672 (10.4) 566 (9.2) 1238 (9.8)
12 738 (11.4) 754 (12.3) 1492 (11.9)
13 925 (14.3) 795 (13.0) 1720 (13.7)
14 976 (15.1) 905 (14.8) 1881 (15.0)
15 842 (13.1) 927 (15.1) 1769 (14.1)
16 853 (13.2) 842 (13.7) 1695 (13.5)
17 693 (10.7) 671 (11.0) 1364 (10.8)
18 355 (5.5) 314 (5.1) 669 (5.3)
Total 6450 (100.0)* 6127 (100.0) 12,577 (100.0)
* Percentages may not add up to 100%, because of rounding errors.
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7
in mean values was calculated by first finding the difference
in means between successive ages, then dividing each result
by its initial value to get its percent change, and then
averaging the summed percent changes by the numbe r of
years correspondin g to the span of the three age groups (i.e.,
by 3 yr for the 10- to 13-yr and 13- to 16-yr groups, and by
2 yr for the 16- to 18-yr group) . The three age groups
correspond to the structure of the Portugal school system:
10–13, second level; 13–16, third level; and 16–18, the
secondary level. Statistical significance criterion was 0.05.
SPSS 14.0 was used in all analyses.
RESULTS
For all four PA indexe s, males had higher mean values
than females at every age (Table 2). Whereas males (except
for LI, which peaked at age 16) had their highest mean
values at age 18 and their lowest at age 10, among females,
the highest mean values occurr ed at age 16 and the lowest
at age 10 (for WSI and for LI) or age 11 (for SI and PAI).
All four indexes had significant differences in their mean
values by age and sex, as well as a significant interaction
between age and sex (P G 0.05). This significant interaction
suggests that the age effects in the PA indexes differed
between males and females; it can be visualized by referring
to Figure 1. Among males, with the exception of LI, mean
values of the indexes tended to rise with age; among
females, mean values generally started to decline after 16
yr. For LI, females of the youngest age groups had lower
mean values than males, with general convergence of this
index at older ages.
For the PAI and SI, the mean difference between male
and female scores at the various ages ranged from 0.53 to
0.80 and from 0.39 to 0.61, respectively (each difference
was significant (P G 0.05)). For WSI, male values were
always at least slightly higher than those for females, and
significant differences by sex were seen at ages 11, 12, 14,
and 18 (differences ranged from 0.06 to 0.13). After age 17,
there wa s a drop for females and an increase (albeit
nonsignificant) for males. For LI, among both sexes there
was an increase from age 10 to 16, then small decreases. All
differences by sex were, again, significant (except at age
18), and these differences ranged from 0.06 to 0.19.
The average annual rate of change in the mean values of
each PA index is shown in Figure 2 by sex for the three age
groupings. For females, in the 10–13 and 13–16 age groups,
the average annual rate of change was positive in seven of
eight cases, with increases ranging from 0.7% per year (for
PAI) to 1.6% per year (for SI and LI); the lone decrease was
j0.2% per year for SI in the 10–13 group. Values for the
TABLE 2. Mean values (SD), F-test, and P value for analysis of variance models of different PA indexes according to age and sex.
Physical Activity Index Sport Index Work/School Index Leisure-Time Index
Age Females Males Females Males Females Males Females Males
10 7.40 (1.10) 7.97 (1.10) 2.31 (0.65) 2.70 (0.66) 2.26 (0.37) 2.28 (0.43) 2.82 (0.54) 2.99 (0.57)
11 7.37 (1.04) 8.09 (1.11) 2.20 (0.61) 2.73 (0.65) 2.28 (0.38) 2.36 (0.40) 2.88 (0.56) 3.01 (0.61)
12 7.51 (1.06) 8.24 (1.14) 2.30 (0.64) 2.78 (0.70) 2.33 (0.38) 2.40 (0.42) 2.88 (0.55) 3.07 (0.57)
13 7.56 (1.09) 8.31 (1.21) 2.29 (0.63) 2.86 (0.72) 2.36 (0.37) 2.38 (0.43) 2.91 (0.57) 3.06 (0.57)
14 7.56 (1.12) 8.33 (1.12) 2.30 (0.67) 2.83 (0.68) 2.33 (0.36) 2.39 (0.41) 2.93 (0.54) 3.11 (0.55)
15 7.58 (1.12) 8.32 (1.09) 2.29 (0.65) 2.84 (0.70) 2.36 (0.37) 2.39 (0.41) 2.93 (0.54) 3.08 (0.55)
16 7.87 (1.18) 8.40 (1.11) 2.40 (0.71) 2.84 (0.67) 2.42 (0.38) 2.43 (0.41) 3.05 (0.55) 3.13 (0.57)
17 7.71 (1.19) 8.37 (1.12) 2.29 (0.67) 2.87 (0.73) 2.41 (0.37) 2.42 (0.40) 3.02 (0.58) 3.08 (0.55)
18 7.63 (1.25) 8.43 (1.22) 2.30 (0.72) 2.91 (0.78) 2.34 (0.36) 2.47 (0.44) 2.99 (0.59) 3.05 (0.54)
Total 7.59 (1.13) 8.28 (1.14) 2.30 (0.66) 2.82 (0.70) 2.35 (0.37) 2.39 (0.42) 2.94 (0.56) 3.07 (0.57)
Results of Analysis of Variance Model*
Sources of Variation FPFPFPFP
Age 18.95 G 0.001 6.28 G 0.001 15.25 G 0.001 11.30 G 0.001
Sex 1050.37 G 0.001 1623.44 G 0.001 37.29 G 0.001 143.95 G 0.001
Age sex 2.13 0.03 3.03 0.002 2.37 0.02 2.63 0.007
* Degrees of freedom for each source of variation: age = 8; sex = 1; age by sex = 8; error = 12559.
FIGURE 1—Mean units of four physical activity indexes for 12,577 Portuguese males and females, ages 10–18 yr.
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16–18 group were all negative and ranged from j 1.0% per
year (for LI) to j2.1% per year (for SI).
For males, the PAI and WSI were similar in that they
showed increases in all three age groupings, which ranged
from 0.2% per year for PAI among those aged 16–18, to
1.5% per year for WSI in the 10–13 group; for both SI
and LI, the pattern was two increases and one decrease,
with the largest decrease being 1.3% per year for 16- to
18-yr-olds in LI. The largest increase was 1.9% per year
for 10- to 13-yr-olds in SI.
DISCUSSION
In this cross-sectional study of adolescents ages 10–18 yr
from four regions of Portugal, we found that males had
greater level s of PA than did females. We also found in
these analyses that mean PA levels increase among both
sexes from age 10 to 16 yr, but after age 16, female students
decrease their PA, whereas their male cou nterparts increase
it, except for PA during leisure time. Should these cross-
sectional results hold true within a longitudinal context, we
would consider an age greater than 16 a ‘very sensitive
period’ for adolescents, a time during which their PA may
often decline.
Our finding that male adolescents in Portugal are more
active than their female counterparts accords with the work
of several other authors (5,7,11,13,23,25,26). Weinberg and
Gould (27) contend that such sex differences may be
grounded in social and cultural factors: historically, males
assimilate roles based on more active work-related activ-
ities, and females assimilate roles directed more toward
the family and housekeeping (12,15). Additionally, those
authors (27) contend that males are given more permis-
sion than females to explore their physical environment,
which might explain greater amounts of walking and
cycling by males.
Our findings run counter to those from some studies of
northern European and American youth (5,7,13,2 3,25) that
show progressive declines in PA levels with increasing age.
Two other studies, however, have results that are in many
ways similar to ours (7,23). In a longitudinal study of
Finnish youth, Telama and Wang (23) report that in a com-
parison of youth ages 12–15 yr with those ages 15–18 yr,
percent declines in the mean PA index became greater with
increasing age (rising from 2 to 2.3% in males and from 1.2
to 1.5% in females). Thus, at about 16 yr, the declines in
PA became greater. We did not find similar progressive
declines in our Portuguese sample from ages 10 to 16 yr.
Instead, mean PA values increased by 0.4–1.9% per year
for males and 0.7–1.6% per year for females (except for SI).
Even so, after age 16, females decreased their PA values by
1–2.1% per year, whereas males increased their PA levels
for all indexes except leisure time (j1.3% per year). In the
other study, Caspersen et al. (7) report that U.S. youth ages
15–18 yr were at greater risk of declining PA than were
those ages 12–15 yr when five different patterns of PA were
examined. Between 15 and 18 yr, the authors found annual
decreases in prevalence to be greater than 5% for regular
sustained and regular vigorous patterns of PA. We found
the greatest declines after age 16, which would fit in the 15–
18 yr age group. We did not, however, find such dramatic
changes for similar ages in our Portuguese sample, but our
assessment procedure could not examine such distinct PA
patterns as were examined in the study by Caspersen and
colleagues (7). Our leisure and sport indexes, which most
closely approximate the two activity patterns assessed by
Caspersen et al. (7), are also mostly congruent with their
overall findings, especially the sport index for females.
Compared with the United States, the absence in our
study of an earlier age-dependent decline in PA during
adolescence may be attributable to sociocultural factors,
different environments, and neighborhood conditions
unique to Portugal, as well as a highly pronounced decline
in sport-specific pa rticipation among U.S. adolescents with
age (6,18). In addition, we should note that in Portugal,
limited available studies suggest that age-related declines
across either childhood or adolescence do not occur (11,26),
which may be attributable to the daily routines of
Portuguese students that require mandatory physical educa-
tion classes, involve plentiful school sport s programs, and
FIGURE 2—Percent change per year for mean units of four physical activity indexes* by three age periods** for 12,577 Portuguese males and
females, ages 10–18 yr.
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allow free recess time, during which PA may ensue. In fact,
during the last 10 yr, a large increase (16.8%) in extra-
curricular sports programs (which include two or three
training practices per week, plus a weekend competition)
has been noted (20). During roughly the same period (from
1998 to 2004) in Portugal, Adelino et al. (2) report that the
number of sports participants outside of school had
increased by 24.3% (from 116,759 to 145,148). Finally,
the majority of Portuguese students walk to and from
school, and city planners have sought to design safe
walkways to support active transportation (8).
Although we do not have any overall findings of declines
in PA with increasing age, other authors (28,29) who have
noted declines in PA during adolescence have found them
to be greater among fema les than among males. The
declines in PA indexes we observed in females after age
16, for which increases were seen in their male counter-
parts, are somewhat congruent with those findings. Wold
and Andersen (28) and Wolf et al. (29) have suggested that
greater observed age-related declines among females are
grounded in social, psychological, and biological changes,
primarily in identity, perceived sexuality, peer pressure, and
social environment. This cluster of factors may produce
changing attitudes toward participation in PA. Female
adolescents frequently abandon or stop doing less important
social activities, and they prefer those that are socially
relevant, reinforcing, and consistent with established sex
rules. The decrease we have noted may have been directly
related to an increase in academic work needed to prepare
for university entra nce examinations. On the other hand,
another possible explanation is that the decline might have
occurred as a means to compensate for time spent in sport
and physical education participation. In contrast to chil d-
hood, during which females readily participate in PA of any
energy demand, during adolescence females usually prefer
activities of low energy demand (13), which may also be
viewed as congruent with posited attitudes, roles, and
circumstances unique to adolescent females (28,29).
The decrease in the leisure PA index after 16 yr was the
only decline we noted for males during this sensitive period.
To understand this further, we examined more closely our
LI, which was based on four questions regarding usual
walking habits, usual cycling, TV viewing, and time spent
in walking, and we found that males had a declining
prevalence of never watching television and of moderate to
intense walking, cycling, and time spent walking between
the ages of 1 4 and 16 yr (data not shown). This tends to
correspond with reports from some U.S. authors (3,10) who
have noted that durin g this age period, males reduce the
number of physical and sports activities practiced inside or
outside of school, instead preferring to spend their free time
in sedentary pursuits such as being with friends, watching
television, or going to the cinema. Among adoles cents from
four regions of Portugal, whether for males or for females,
as noted above, this decline in leisure activity may occur
because of rapidly approaching higher education, as the
transition to a university may force changes in a student_s
interest toward spending his or her free time in less active
leisure pursuits.
There are several limitations associated with our analy-
ses. First, our data were based on self-reports, and, thus,
they may have resulted in estimates different from what
would have been produced by objective assessment, albeit
that has its own limitations. Second, we used the Baecke
questionnaire, which may yield different estimates of PA
than those obtained in studies of similarly aged youth that
used different in strum ents. In addition, some common
conditioning activities, such as running and strength train-
ing, may not have been fully captured by the sport index of
the Baecke questionnaire if the student had not perceived
them as sports. Unfortunately, most studies rarely use the
same instrument, making the ability to compare their results
somewhat tenuous (21). Because children and adolescents
are often unable to accurately supply the details regarding
the frequency, intensity, and duration of multiple, different
types of physical activities (21), it is difficult to declare
which instrument is truly the best to use. Despite such
nuances between questionnaires, we were at least able to
see mean annual percentage declines that were somewhat
similar to those reported for Finnish youth (23). There is at
least one additional advantage of the Baecke questionnaire
in that it offers estimates for sport, leisure, and work/school
that are forged from items representing both positive and
negative contributions to each index. Third, we used trained
teachers to administer the questionnaire and to address
students_ concerns, which might have induced a potential
bias different from that associated with using only study
investigators or staf f. Fourth, there are potential clustering
effects resulting from influences of school and class, for
which we could not adjust, given the data available. Finally,
we used a cross -sectional design, which may not accurately
reflect individual change in PA over time, as would be
found with a longitudinal cohort of, say, 12-yr-old children
measured repeatedly until age 18. Our cross-sectional
design , nonetheless, allowed the gathering of data fo r
young people representing each of 9 yr of age at one time,
thereby saving time and money. It also afforded a more
consistent assessment methodology free of temporal effects
when, for example, climate or other environmental circum-
stances change over a prolonged period of monitoring. The
cross-sectional design has an additional advantage because
it averts any intervention effect that might occur from
repeated questioning about PA, which would occur with a
longitudinal design.
CONCLUSIONS
In summary, our findings of greater activity levels among
males than among females in these four Portuguese regions,
and the decline for females during the sensitive period
after age 16, suggest that efforts be made to establish
and maintain sufficient PA levels among girls and young
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women as an essential part of a healthy lifestyle. These
efforts should involve family, friends, and school staff,
particularly the physical educat ion teacher, as important
agents of behavioral change.
This study was supported by the Portuguese Foundation of
Science and Technology: SFRH/BD/20166/2004.The findings and
conclusions in this report are those of the author(s) and do not
necessarily represent the views of the Centers for Disease Control
and Prevention.
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http://www.acsm-msse.org70 Official Journal of the American College of Sports Medicine
BASIC SCIENCES
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  • Source
    • "This questionnaire comprises a total of 16 questions, and maps three PA domains: school/work, leisure-time (PA le ), and sport participation (PA sp ). Individual question scores varied from 1 to 5. Baecke's questionnaire has been consistently used in Portuguese speaking countries, Portugal [38,39] and Brazil [40,41], as well as in Peru [30,42] and its adaptation was done according to the following steps: first a translation from English to Portuguese was done by an English-speaking expert; second, word accuracy and meaning were discussed with questionnaire development specialists from the University of Porto; third, pilot studies were done in order to find out if children/youth clearly understood what was being asked; fourth, to verify the consistency with which children/youth respond reliability studies were done; fifth, Brazilian versions were already available and re-checked with the Portuguese version; sixth, a Peruvian version were also made according to steps 1 to 4. For the purposes of the present study the total PA score was obtained only from the sum of scores of leisure time PA and sport participation. All schoolchildren answered the questionnaires during their physical education classes under the supervision of the teacher of Physical Education who underwent training sessions provided by the research team members. "
    [Show abstract] [Hide abstract] ABSTRACT: Children from developed and developing countries differ in their body size and shape due to marked differences across their life history caused by social, economic and cultural differences which are also linked to their motor performance (MP). We used allometric models to identify size/shape characteristics associated with MP tests between Brazilian and Peruvian schoolchildren. A total of 4,560 subjects, 2,385 girls and 2,175 boys aged 9–15 years were studied. Height and weight were measured; biological maturation was estimated with the maturity offset technique; MP measures included the 12 minute run (12MR), handgrip strength (HG), standing long jump (SLJ) and the shuttle run speed (SR) tests; physical activity (PA) was assessed using the Baecke questionnaire. A multiplicative allometric model was adopted to adjust for body size differences across countries. Reciprocal ponderal index (RPI) was found to be the most suitable body shape indicator associated with the 12MR, SLJ, HG and SR performance. A positive maturation offset parameter was also associated with a better performance in SLJ, HG and SR tests. Sex differences were found in all motor tests. Brazilian youth showed better scores in MP than their Peruvian peers, even when controlling for their body size differences The current study identified the key body size associated with four body mass-dependent MP tests. Biological maturation and PA were associated with strength and motor performance. Sex differences were found in all motor tests, as well as across countries favoring Brazilian children even when accounting for their body size/shape differences.
    Full-text · Article · Apr 2016 · PLoS ONE
  • Source
    • "In addition, research examining participation throughout childhood and adolescence has shown that PA rates generally decline rapidly with age (Findlay et al., 2010; Trost et al., 2002 ). In Portugal, crosssectional studies are congruent with these findings (Carreiro da Costa & Marques, 2011; Seabra et al. 2008) and, on the other hand, evidenced that the incidence of adults that met the recommended amount of PA is low (Marques et al., 2012). Therefore, because PA habits developed early in life may persist into adulthood (Gordon-Larsen et al., 2004; Kjonniksen et al., 2009; Malina, 2001), understanding the factors that influence young people to become active in their daily life and why some of them prefer to adopt a sedentary lifestyle seems to assume a real research value. "
    [Show abstract] [Hide abstract] ABSTRACT: This study sought to analyse the narratives of adolescents who have adopted an active or a sedentary lifestyle, and to identify psychological, behavioural, social and environmental variables related to an active and a sedentary lifestyle among adolescents. Narrative interviews were conducted with 2 girls (1active and 1 sedentary) and 2 boys (1 active and 1sedentary). Thematic analysis identified a number of key personal, social and environmental influences on physical activity (PA) that distinguished the two groups of students, through their childhood and adolescence. These included PA history, the value of sedentary behaviours, social support from family and friends for PA, safety and PA facilities in the local neighbourhood, PA participation in school besides Physical Education (PE), primary and secondary school and experiences in PE, PE teachers and PE peers, PA and health knowledge and perception of PE goals, and attitudes toward school and PE.
    Full-text · Article · Jun 2015 · Revista Internacional de Medicina y Ciencias de la Actividad Fisica y del Deporte
  • Source
    • "A decline in daily physical activity and activity energy expenditure is often assumed across the adolescent years, although not all studies support this trend. For example, in a large sample of Portuguese youth aged 10–18 years, school-and sport-related activities declined in females while both school-and sport-related physical activities increased with age in males (Teixeira e Seabra et al., 2008). In the present study, physical activity objectively assessed (counts per minute) did not differ among younger and older girls, but younger boys showed significantly higher levels of physical activity thanFigure 6. Bland-Altman plot for activity energy expenditure (AEE) of overweight/obese adolescents showing the difference between the diary and accelerometer estimates plotted against the mean of the two estimates. "
    Dataset: JSS 2011
    Full-text · Dataset · Feb 2015
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