http://www.medscape.com/viewarticle/561484

Effects of Modifying Physical Activity and Sedentary Behavior on
Psychosocial Adjustment in Overweight/Obese Children

Gary S. Goldfield, PhD; Risa Mallory, MEd; Torrey Parker, MSc; Terrell
Cunningham, BA; Christine Legg, BA; Andrew Lumb, BA; Kasey Parker; Denis
Prud'homme, MD, MSc; Kristi B. Adamo, PhD
J Pediatr Psychol. 2007;32(7):783-793. ©2007 Oxford University Press
Posted 08/17/2007

Abstract and Introduction

Abstract

Objectives: To evaluate the relationship between changes in physical
activity (PA), sedentary behavior, and physical self-perceptions and global
self-worth in 30, 8–12 years old, overweight/obese children (13 boys, 17
girls).
Methods: Secondary analyses from a randomized controlled trial designed to
increase PA and reduce sedentary behavior. PA was measured by accelerometers
worn by participants every day for 8 weeks. Sedentary behavior, defined as
minutes per day spent in television viewing, was assessed by self-report.
Results: Increases in PA were associated with increases in perceived
physical conditioning (r = .54, p < .01), body satisfaction (r = .55, p <
.01), and overall physical self-worth (r = .44, p < .05) independent of
changes in body mass index (BMI). Reductions in TV viewing were also related
to increased physical and global self-worth.
Conclusions: Increases in PA are associated with improvements in physical
self-perceptions but not global self-worth, while reductions in TV viewing
are associated with increased physical and global self-worth, and these
psychosocial benefits appear to be independent of changes in adiposity.

Introduction

Child obesity is increasingly being recognized as a global epidemic
(Tremblay & Willms, 2000; World Health Organization, 2002) and represents a
serious public health concern given its associated health complications
(Dietz, 1998; Janssen et al., 2005b). In addition to adverse medical
effects, there is a growing body of evidence indicating deleterious
psychosocial sequelae of obesity in youth (Gortmaker, Must, Perrin, Sobol, &
Dietz, 1993). This includes, but is not limited to, depression (Goodman &
Whitaker, 2002), weight-based teasing (Eisenberg, Neumark-Sztainer, & Story,
2003), and social isolation and discrimination (Latner & Stunkard, 2003),
all of which have been shown to have negative effects on self-esteem in
overweight youth (Eisenberg et al., 2003; Pierce & Wardle, 1997). Although
many clinical (Zeller, Saelens, Roehrig, Kirk, & Daniels, 2004) and
epidemiological (French, Perry, Leon, & Fulkerson, 1996) studies support the
notion that body mass index (BMI) is inversely related to self-esteem in
youth, comprehensive review papers have not consistently shown obese youth
to have lower global self-esteem than nonobese peers (French, Story, &
Perry, 1995; Wardle & Cooke, 2005). However, the relationship appears much
stronger when obese and nonobese children are compared on self-esteem
related to physical self-perceptions (Braet, Mervielde, & Vandereycken,
1997) and physical quality of life (Swallen, Reither, Haas, & Meier, 2005).
Perceived deficits in physical self-perceptions are often associated with
real deficits (Raudsepp & Liblik, 2002), both of which may act as barriers
to participating in physically active games or sports. Thus, it is not
surprising that low scores on perceived physical competence are consistently
associated with reduced PA, and high scores on perceived physical competence
are predictive of more regular and frequent physical activity (PA) in
children (Crocker, Eklund, & Kowalski, 2000; Norman, Schmid, Sallis, Calfas,
& Patrick, 2005). These physical self-perceptions have also been shown to be
important indicators of motivation to be physically active (Biddle & Mutrie,
2001), making them critical components in the context of identifying
modifiable variables that may lead to, or result from, more sustained PA
participation in overweight children.

One of the most reliable psychological correlates relating to physical
self-perceptions in obese children is body dissatisfaction or physical
appearance esteem. Mounting evidence from systematic reviews indicates that
overweight/obese children, especially girls, exhibit greater dissatisfaction
than normal-weight peers in clinical and community-based samples
(Ricciardelli & McCabe, 2001; Wardle & Cooke, 2005). This is clinically
significant because body dissatisfaction is not only a consequence of
obesity; it is directly related to unhealthy restrictive dieting behaviors
that are cross-sectionally and prospectively related to weight gain in youth
(Field et al., 2003) and adults (French et al., 1994). Thus, lifestyle
intervention that enhances body image and other physical self-perceptions
should not only provide psychological benefits, but these benefits may
translate to more sustained PA and improved eating behavior needed to induce
negative energy balance and weight loss. Increasing PA and reducing
sedentary behavior in overweight/obese youth may be one method of achieving
these aims (Biddle, Sallis, & Cavill, 1998).

Obese children are a group who may particularly benefit from increased
energy expenditure from physical activity given that they are less
physically active (Bar-Or et al., 1998; Sallis et al., 1992) and less fit
(Johnson et al., 2000; Mamalakis, Kafatos, Manios, Anagnostopoulou, &
Apostolaki, 2000) than nonobese children, and because obesity and sedentary
lifestyles track from childhood to adulthood (Stark, Atkins, Wolff, &
Douglas, 1981). In addition, TV watching is a sedentary behavior that
consumes a large part of children's leisure time (Gortmaker et al., 1996;
Olds, Ridley, Dolman, 2006), and is cross-sectionally (Andersen, Crespo,
Bartlett, Cheskin, & Pratt, 1998; Hancox & Poulton, 2006) and prospectively
related to the development of obesity in children (Gortmaker et al., 1996)
and adults (Viner & Cole, 2005), and negatively correlated with physical
activity (Andersen et al., 1998; Janssen et al., 2005a) and fitness (Durant,
Baranowski, Johnson, & Thompson, 1994). Moreover, physically active children
report greater body satisfaction, self-esteem, and physical self-perceptions
than sedentary peers (Biddle et al., 1998), and increasing PA and exercise
improves global self-esteem in youth (Ekeland, Heian, Hagen, Abbott, &
Nordheim, 2004). Importantly, there is evidence that the psychological
benefits of increased PA in youth are often independent of changes in body
mass (Ekeland et al., 2004), but this issue needs further study.

Using sedentary behavior to reinforce physical activity, a behavior
modification technique known as the premack principle (Premack, 1959),
increases PA and reduces sedentary behavior in normal-weight and obese
children in the laboratory (Goldfield, Kalakanis, Ernst, & Epstein, 2000;
Saelens & Epstein, 1998), as well as adiposity in obese children in the
natural environment (Faith et al., 2001; Goldfield et al., 2006). Very few
clinical trials have examined the effects of modifying PA and sedentary
behavior on psychological well-being in overweight/obese children, as most
of this research has utilized cross-sectional samples or epidemiological
cohorts rather than randomized controlled trial designs. Thus, the aim of
this study was to examine the effects of an intervention designed to
increase PA while reducing TV viewing (Goldfield et al., 2006) on changes in
physical self-perceptions and global self-worth in overweight/obese
children, and evaluate the degree to which this relationship is influenced
by changes in body composition. We predicted that increases in PA rather
than reductions in sedentary behavior would predict improvements in body
image and other physical self-perceptions and global self-esteem, and this
relationship would exist independent of body composition change. It was also
of interest to examine the degree to which changes in intensity of PA
related to changes in psychosocial adjustment.

Methods

The criteria to define overweight and obesity used in this study are based
on the International Obesity Task Force guidelines (www.iotf.org), which
differ from the Center for Disease Control definition stating that BMI above
the 85th percentile for age and sex is considered "at risk of overweight"
and BMI above the 95th BMI is "overweight" (www.cdc.gov). Forty-six children
were screened for eligibility. Thirty, 8–12 years old overweight/obese
children who participated with their parents in an 8-week PA randomized
control trial met the following inclusion criteria: (a) 8–12 years old
children with a BMI of 85th–95th BMI percentile (overweight) or greater than
95th BMI percentile (obese) for age and sex (Kuczmarski, Ogden, Guo, et al,
2002); (b) watching 15 h of self-reported TV per week or more, including
VCR/DVD use and video game playing; (c) engaging in <60 min of self-reported
moderate to vigorous PA per day (Pate et al., 1995); (d) without conditions
that would limit PA; (e) both child and parent agreed not to participate in
any other exercise or weight control program during the course of the study;
(f) no regular participation in swimming or strength training (activities
that cannot be measured properly by accelerometry); (g) willingness of the
parents to enforce or maintain the contingencies or lack of, as reflected by
their assigned study group; (h) parent providing signed informed consent,
and child providing signed informed assent. Subjects were reimbursed for the
parking and transportation costs associated with attending the baseline and
posttreatment assessments as well as the bi-weekly meetings. Baseline
characteristics of participants in each study group are shown in Table I.
The sample was predominantly Caucasian (28 of 30). This study was approved
by the Research Ethics Board at the Children's Hospital of Eastern Ontario.

Design and Procedures

The randomized controlled trial was conducted at the Children's Hospital of
Eastern Ontario from September 2003 to June 2004. Thirty families were
randomized to PA monitoring and feedback plus reinforcement (TV access)
(open-loop feedback + reinforcement, n = 14) versus PA monitoring and
feedback only (open-loop feedback alone, n = 16). None of the participants
dropped out of the study. Children in both groups were provided objective
feedback on their PA by wearing a PA monitor (BioTrainer; Individual
Monitoring Systems, Baltimore, MD, USA). However, children in the open-loop
feedback plus reinforcement group were rewarded with access to television
based on the amount of PA accumulated, whereby 400 activity counts on the
activity monitors, equivalent to about 1 h of moderate to vigorous PA (MVPA;
Goldfield et al., 2006), provided 1 h of access to TV/VCR/DVD and TV-based
computer games. TV access was controlled by a Token TVâ„¢ electronic device
(Stokes Corporation, St. Mazomanie, WI, USA). Participants were required to
install these electronic devices on each TV in the house and if they
encountered any difficulties with installation, a research assistant was
sent to the house to provide assistance. Each token provided 30 min of TV
access followed by immediate shut off and the TV would not restart unless
more tokens were inserted. At least one participating parent in the
intervention group was subjected to the same contingencies as targeted
children, but siblings and nonparticipating parent were given unlimited
tokens so they could watch as much TV as desired. Families in the
intervention group were instructed not to allow targeted children to watch
TV on other family members' tokens. Children were free to accumulate
physical activity counts by engaging in any and all types of activities they
desired, except swimming since the accelerometers were not waterproof.

Children in the open-loop feedback control group were provided feedback on
PA but did not have the token TV devices, hence had free access to TV. These
children were required to visit the laboratory for activity monitor
downloading according to the same schedule as the intervention group.
Families in this group were not given any activity goals to avoid
confounding goals with the effects of the feedback from activity monitors.
More specific information of the trial methodology and procedures are
reported elsewhere (Goldfield et al., 2006).

Measurement

Demographics were evaluated by self-report and socioeconomic status was
assessed by the sum of parental income. Medical history and current medical
problems or physical conditions that contraindicate PA were evaluated by
self-report and clinical interview.

Body Composition. Child weight was assessed to the nearest 0.1 kg with
subjects wearing light clothing without shoes using a calibrated balance
beam scale. Height was assessed using a Health-O-Meter stadiometer. Height
and body weight were measured at baseline and 8-week follow-up assessment
and used to determine BMI defined as weight in kg over height in m2 (kg/m2).
We chose to use BMI rather than z-BMI in light of new research indicating
that traditional BMI is more sensitive to change over time than z-BMI (Cole,
Faith, Pietrobelli, & Heo, 2005), making it more suitable to evaluate
intervention effects.

Measurement of Daily PA. PA was objectively measured by the BioTrainer® (IM
Systems, Baltimore, MD, USA), a small, unobtrusive accelerometer validated
under laboratory and field conditions (Welk, Blair, Wood, Jones, & Thompson,
2000), that has detected significant increases in PA in clinical outcome
research (Andersen et al., 1999). The BioTrainer® provides minute-by-minute
measures of PA, and thus can provide information on when children are active
and not active, and the intensity of activity performed. Total activity
counts, average daily activity counts, time spent in MVPA (3–5.9 METS), and
vigorous physical activity (VPA ≥ 6 METS) (Pate et al., 1995) were
calculated from data downloaded from the Biotrainer® at 7-day baseline,
bi-weekly during the intervention, and 8-week posttreatment.

Self-reported Behaviors. The Past Day Physical Activity recall (PD-PAR), a
valid self-report measure of PA in children (Weston, Petosa, & Pate, 1997),
including obese children, was used in combination with the BioTrainer® to
indicate what children were doing when they were active and sedentary.
Participants were asked to use the PD-PAR daily to record all targeted and
nontargeted forms of sedentary behaviors, as well as physical activities
throughout each day of the week during baseline and posttreatment assessment
periods, as well as daily during the intervention. The PD-PAR was also used
with interviews at screening to assess eligibility. Children self-reported
the amount of time they wore the activity monitor by writing the time of day
they put the monitor on and when they took it off, using a self-report form
prepared by the investigative team. The self-reported activity was compared
with the objective activity monitors to verify accuracy of reporting when
activity monitors were worn, and discrepancies between self-report and
activity monitors were addressed with families in the bi-weekly meetings.

Physical Self-perceptions. Physical self-perceptions were assessed using the
Physical Self-Perception Profile for Children (PSPP-C; Fox & Corbin, 1989;
Eklund, 1997). This 36-item inventory is designed to measure children's
perceived competence in five domains of functioning: Sport, Physical
Conditioning, Body Appearance, Strength, and a higher order construct—the
Physical Self-Worth scale. The Harter Global Self-Esteem subscale (Harter,
1985) was added to evaluate the extent to which the child likes
himself/herself as a person and is happy with the way he/she is. As such,
this dimension constitutes a global dimension of one's self-worth as a
person, rather than domain-specific competency or adequacy. These domains
were discriminated from each other through factor analytic procedures (Fox &
Corbin, 1989). The PSPP-C adopts a response format that includes both
positively and negatively worded phrases to control for socially desirable
responses. Each response has two components whereby children first choose
the direction and then the intensity of their response. For example, they
would first circle one of the following two statements that is most true of
themselves: "some kids are often unhappy with themselves" BUT "other kids
are pretty pleased with themselves." The second step in completing responses
would be to rate whether the statement circled is "sort of true for me" or
"really true for me." Items are scored on a 4-point rating scale (1–4), with
higher numbers reflecting greater competence and self-esteem.

Analytic Plan

The relationship between changes in overall PA and self-perceptions and the
degree to which this relationship is influenced by changes in body
composition were evaluated in two ways. First, between-group changes on the
six domains of physical and global self-perceptions were evaluated using an
intention to treat approach with a mixed analysis of variance and covariance
models. The ANOVA/ANCOVA consisted of a between-subjects factor of group
(open-loop feedback + reinforcements vs. open-loop feedback only), as well
as a repeated measures factor of Time (Baseline vs. Posttreatment), with the
six domains of physical self-perceptions serving as the dependent measures,
and baseline BMI as a covariate. A significant Group × Time interaction and
post hoc tests using Fisher's exact tests were used to determine if the
intervention provided psychosocial benefits independent of BMI. Two,
pre–post change scores were created, and the magnitude of correlation
between the changes in overall PA (total counts per day), minutes per day in
MVPA, minutes per day in VPA, targeted sedentary behavior, and
self-perceptions were evaluated by Pearson Product Moment correlations with
and without partialing out changes in BMI. In addition, correlations between
changes in BMI and physical self-perceptions were also conducted. In all
analyses, we used two-tailed alpha values set at 0.05. Statistical analyses
were conducted using the Statistical Package for the Social Sciences (SPSS
13.0).

Results

Demographic and anthropometric characteristics of the sample are reported in
Table I . No group differences emerged on these variables.

ANOVAs yielded significant Group × Time interactions indicating that,
compared with controls, the intervention group demonstrated significantly
greater changes in total physical activity counts [F(3, 84) = 3.79, p <
.05], and time spent in MVPA [F(3, 84) = 2.8, p < .05]. The Group × Time
interaction for VPA was not significant.

There was a significant Group × Time interaction on several dependent
measures. Controlling for BMI at baseline, the intervention group exhibited
significantly greater improvements in perceived Physical Conditioning [F(1,
27) = 4.5, p = .036], Body Appearance [F(1, 27) = 4.0, p = .04], and
Physical Self-Worth [F(1, 27) = 4.8, p = .02] compared with controls.
Between-group differences on the Sport, Strength, and Global Self-Esteem
were not statistically significant. The results of analyses of physical
self-perception scales are shown in Table II . Neither the main effects of
time nor group were significant for any of the dependent measures when
controlled for BMI.

Correlational analyses indicated that increases in PA were associated with
increases in Body Appearance (r = .43, p = .017), Condition (r = .38, p =
.04), and Physical Self-Worth (r = .44, p = .01). As shown in Table III ,
these relationships remained significant after controlling for changes in
BMI. Changes in PA were not associated with changes in Strength, or Global
self-Esteem. Changes in targeted sedentary behavior (i.e., TV viewing) were
not related to changes in physical self-perceptions when BMI was not
controlled for, but were inversely related to Physical Self-Worth (r = –.38,
p = .05) and Global Self-Esteem (r = –.36, p = .05) when BMI was
statistically controlled for. The improvements in self-perceptions were more
strongly correlated with overall volume (total counts) of PA rather than
intensity, as shown in Table III .

A significant Group × Time interaction emerged for BMI [F(1, 28) = 3.9, p <
.05] indicating greater improvements for intervention group (pre: 28.9 ±
6.2; post: 28.3 ± 6.6) compared with control (pre: 28.2 ± 3.0; post: 28.5 ±
3.1). Changes in BMI were not related to changes in physical
self-perceptions ( Table IV ).

Discussion

To our knowledge, this is the first study to examine the effects of
open-loop feedback to increase PA on psychosocial adjustment in
overweight/obese children. Data from the current study indicate that
increases in overall PA are associated with improvements in Body
Satisfaction, perceived Physical Conditioning, and perceived Physical
Self-Worth, and these psychological benefits were independent of reductions
in BMI.

Despite the study intervention not resulting in "visible" change in BMI
(Goldfield et al., 2006), there remained a relationship between increased PA
and improved body appearance esteem. This finding, previously reported in
youth (Kirkcaldy, Shephard, & Siefen, 2002), has important clinical
implications. Many overweight children experience weight-based teasing (Puhl
& Brownell, 2001), which likely serves to exacerbate body dissatisfaction
that is already prevalent in this population (Wardle & Cooke, 2005). It is
interesting to note that while one may expect self-esteem to increase in
association with improved body satisfaction, our data indicate that
increased PA was only associated with improved physical, but not global,
self-worth, highlighting that the correlation between body esteem and
self-esteem is not linear or symmetrical in overweight/obese children
(Wardle & Cooke, 2005). The fact that PA was associated with increased body
image and several other domains of self-perception, but not global
self-esteem, is inconsistent with systematic review findings indicating PA
increases self-esteem and emotional well-being in children (Ekeland et al.,
2004; Gruber, 1986). Perhaps this discrepancy in findings is due, in part,
to the fact that most trials included in these reviews were not based on
clinical samples of obese children. It appears that the current sample of
overweight/obese children may be evaluating their global self-worth on many
domains that extend well beyond merely PA and body image. This
self-perception may provide psychological advantages given that over
investment in body weight and shape is associated with increased risk of
engaging in unhealthy eating and weight control practices, and full-blown
eating disorders (American Psychiatric Association, 1994). Given that many
obese children presenting for treatment have difficulty losing weight and
maintaining the losses, it is encouraging to note that body image and
physical self-worth can be enhanced, independent of weight loss simply by
getting overweight children more physically active. Moreover, given that
body dissatisfaction often elicits restrained eating or dieting for weight
loss in overweight children (Casper & Offer, 1990; Field et al., 1999),
combined with evidence that dieting leads to weight gain in youth (Field et
al., 2003; Shunk & Birch, 2004), future research is needed to determine
whether improved body image resulting from increased PA in overweight
children translates to healthier eating behavior and weight management.

Our findings indicating that increases in PA were associated with increases
in physical self-perceptions, independent of BMI, is consistent with
previous research in mainly normal-weight children (Crocker et al., 2000)
and adolescents (Crocker et al., 2003), and provides evidence that PA
interventions can be empowering in the context of perceived competence in
physical abilities in overweight/obese children. This finding is important
knowing that physical self-worth is predictive of subsequent PA and sport
participation (Biddle et al., 2001), which may provide greater opportunity
to increase energy expenditure needed for weight loss or weight maintenance
throughout growth in this patient population.

Today's children spend more time watching TV and playing video games than
any other activity besides sleeping (The Annenberg Public Policy Center of
the University of Pennsylvania, 1997), and obese children, in particular,
spend more time in these sedentary activities (Dietz & Gortmaker, 1985).
Interestingly, reductions in TV viewing were associated with improvements in
physical and global self-worth, but only when changes in BMI were
statistically controlled. To the best of our knowledge, we are the first to
document a relationship between reduced TV viewing and increased global
self-worth in this population. One possible explanation for this finding may
be that successfully reducing TV viewing may have enhanced feelings of
self-discipline or self-control that psychologically empowered children to
feel better about themselves. Additionally, children and youth are
particularly vulnerable to the messages conveyed through TV, which have been
shown to adversely influence their self-image and aggressive behaviors
(American Academy of Pediatrics, 2001). Therefore, a reduction in viewing
time may increase self-esteem by reducing exposure to unhealthy messages and
unrealistic body images displayed on TV. Alternatively, reductions in TV
viewing may conceivably lead to improved physical and global self-worth by
increasing PA (Epstein, Roemmich, Paluch, & Raynor, 2005). However, our data
indicate that improved global self-worth was not related to changes in PA;
thus, given the multidimensional nature of self-esteem, increasing PA alone
may not be sufficient to increase global self-esteem in overweight and obese
children.

Regardless of the mechanism, the finding that reducing TV is predictive of
improved self-esteem is important because good self-esteem is a predictor of
physical health (Rhee, Holditch-Davis, & Miles, 2005) and is also a
well-accepted measure of psychosocial health in youth (Rotenberg et al.,
2004). Moreover, self-esteem has reliably been shown to predispose to, or
buffer against, the development of numerous psychiatric disorders, including
eating disorders (Fairburn, Welch, Doll, Davies, & O'Connor, 1997). Future
research is needed to replicate and further understand how reductions in TV
viewing are associated with enhanced self-esteem in overweight children.

The relationship between changes in intensity of PA and physical
self-perceptions and global self-esteem in overweight/obese children has not
been well studied. Our data indicate that overall volume (total counts) of
PA was more closely associated with improvements in physical self-worth than
MVPA, and in fact, there was virtually no relationship between changes in
VPA and self-perceptions. Research suggests that obese children find it more
difficult to sustain bouts of higher intensity PA than normal-weight
children (Dishman, 1991; therefore, attempting to be active at these
intensities may be disempowering and affect adherence resulting in reduced
physical self-perceptions. Conversely, increasing volume of PA at lower
intensities may provide a sense of mastery and empowerment in relation to
physical competencies. This finding, if replicated, has clinical relevance
in that overall volume of PA in youth may be more important for providing
psychosocial health benefits than higher intensity PA designed to improve
fitness (Rowland & Freedson, 1994). In addition, encouraging
overweight/obese children to engage in higher volume, lighter intensity PA
may be a more realistic goal that would likely yield better adherence and
may contribute to weight control (Rowlands, Eston, & Ingledew, 1997).

This study has several limitations. Although novel research questions were
posed, the small sample size makes it difficult to evaluate how
generalizable these results are to preadolescent overweight/obese children.
The sample size of primarily Caucasian children also precludes a meaningful
evaluation of how gender or ethnicity influence the relationship between
activity changes and psychosocial adjustment. Although changes in
relationships were evaluated longitudinally, the study period was only
8-weeks and long-term follow up with multiple evaluations are needed to
better determine how changes in volume and intensity of PA performed predict
changes in physical and global self-worth in this population, and whether
these changes are maintained after the intervention is stopped.

In summary, data from the current study indicate that increases in overall
volume (total counts) of PA are associated with improvements in perceived
physical conditioning, body satisfaction, and overall physical self-worth,
and these improvements in psychosocial adjustment were not due to changes in
body composition. Improvements in physical self-perceptions were more
closely related to overall volume (total activity counts) of PA than
intensity of PA, but this finding needs replication with larger samples and
less sedentary children who engage in greater amounts of MVPA and VPA.
Reductions in TV viewing were associated with increases in physical and
global self-worth, independent of changes in BMI, thereby identifying
additional psychological health benefits of reducing reinforcing sedentary
behavior. Collectively, our findings indicate that behavioral interventions
that increase PA and reduce TV viewing may be effective in improving weight
control, and may also provide concomitant psychosocial benefits to a
pediatric population in need. Future research incorporating longitudinal
designs with multiple follow-ups are needed to more accurately determine
whether changes in activity provide psychosocial benefits, or whether
improvements in psychosocial functioning lead to increased PA and reduced
sedentary behavior, or both.


Table 1. Mean (± SD) Characteristics of the Sample at Baseline


Variable Intervention (n = 14) Control (n = 16) p
Gender (M/F)a 6/8 7/9 .961
Age 10.0 (.90) 10.7 (1.4) .133
Height (cm) 145.0 (8.7) 151.8 (11.6) .090
Weight (kg) 61.5 (16.9) 65.6 (13.9) .473
BMI (kg/m2) 28.9 (6.2) 28.2 (3.0) .691
Combined parental incomea
Below $50,000 2 (14.3%) 4 (25%) .272
Between $50,000–75,000 5 (36%) 6 (38%) .891
Above $75,000 7 (50%) 6 (38%) .650
Physical activity (counts/day) 247.0 (131.2) 206.8 (119.0) .386
MVPA (min/day) 14.4 (7.8) 12.0 (11.3) .513
VPA (min/day) 3.7 (4.9) 1.2 (1.6) .091
Targeted sedentary behavior (min/day) 160.5 (93.7) 152.1 (86.5)
.799
Nontargeted sedentary behavior (min/day) 34.0 (17.5) 41.5 (41.7)
.530
MVPA, Moderate to vigorous physical activity; VPA, vigorous physical
activity.
aGroup differences in gender and parental income were determined by
chi-square test. Differences in other variables determined by independent
t-tests.


Table 2. Adjusted Means (and SDs) of Changes in Physical Self-perceptionsa


Variable and assessment period Intervention (n = 14) Control (n = 16)
Group × Time p-value
Sport
Baseline 15.5 (2.6) 15.9 (2.8)
Postintervention 17.1 (3.4) 16.8 (3.1) .478
Change (post minus pre) 1.6 (3.4) 0.9 (2.5)
Physical Conditioning
Baseline 14.4 (2.1) 14.2 (3.1)
Postintervention 17.3 (2.7) 15.0 (2.5) .043
Change (post minus pre) 2.9 (2.7) 0.8 (2.0)
Body Appearance
Baseline 12.4 (4.7) 12.2 (3.8)
Postintervention 15.3 (3.4) 11.8 (3.6) .050
Change (post minus pre) 2.9 (4.7) –0.4 (3.8)
Strength
Baseline 18.4 (3.8) 16.6 (4.2)
Postintervention 18.8 (3.9) 18.6 (3.6) .251
Change (post minus pre) 0.4 (3.6) 2.0 (3.6)
Physical Self-Worth
Baseline 14.2 (3.4) 13.8 (4.2)
Postintervention 16.9 (2.5) 14.1 (4.8) .037
Change (post minus pre) 2.7 (2.9) 0.3 (3.1)
Global Self-Worth
Baseline 16.2 (4.5) 15.6 (4.2)
Postintervention 17.1 (3.6) 16.2 (4.9) .741
Change (post minus pre) 0.9 (2.6) 0.6 (4.5)
aScores adjusted for baseline BMI using ANCOVA.


Table 3. Pearson's Correlations between Changes in Physical Activity Level,
Intensity, TV, and Self-Perceptions


ΔSelf-perceptions Uncontrolled BMI controlled
ΔPA ΔMVPA ΔVPA ΔTV ΔPA ΔMVPA ΔVPA ΔTV
Sport .18 .15 .12 –.17 .16 .09 .12 –.14
Conditioning .54** .41* .26 –.16 .54** .42* .26 –.24
Body Appearance .53** .36* .23 –.13 .55** .38* .27
–.22
Strength .22 –.12 .10 –.14 –.22 –.12 .10 –.11
Physical Self-Worth .44* .24 .07 –.24 .44* .23 .07
–.38*
Global Self-Worth –.13 –.15 –.14 –.13 –.11 –.13
–.14
–.36*
ΔSelf-perceptions, post minus baseline change scores on self-perception
subscales; ΔPA, changes from baseline through intervention of total physical
activity pedometer counts per day; ΔMVPA, changes from baseline through
intervention of minutes per day spent in moderate to vigorous physical
activity; ΔVPA, changes from baseline through intervention of minutes per
day spent in vigorous physical activity; ΔTV, changes from baseline through
intervention of minutes per day spent watching television.
*p < .05, **p < .01.


Table 4. Pearson's Correlations between Changes in BMI and Changes in
Self-Perceptions


ΔSelf-perceptions ΔBMI
Sport .10
Conditioning .01
Body Appearance .10
Strength .08
Physical Self-Worth .05
Global Self-Worth .18
ΔSelf-perceptions, post minus baseline change scores on self-perception
subscales; ΔBMI, post minus baseline change scores on BMI.




References

American Academy of Pediatrics. Children, adolescents, and television.
Pediatrics (2001) 107:423–426.
American Psychiatric Association. Diagnostic and statistical manual of
mental disorders (1994) 4th. Washington, DC: American Psychiatric
Association.
Andersen RE, Crespo CJ, Bartlett SJ, Cheskin LJ, Pratt M. Relationship of
physical activity and television watching with body weight and level of
fatness among children: Results from the Third National Health and Nutrition
Examination Survey. Journal of the American Medical Association (1998)
279:938–942.
Andersen RE, Wadden TA, Bartlett SJ, Zemel B, Verde TJ, Franckowiak SC.
Effects of lifestyle activity vs structured aerobic exercise in obese women:
a randomized trial. Journal of the American Medical Association (1999)
281:335–340.
Bar-Or O, Foreyt J, Bouchard C, Brownell KD, Dietz WH, Ravussin E, et al.
Physical activity, genetic, and nutritional considerations in childhood
weight management. Medicine & Science in Sports & Exercise (1998) 30:2–10.
Biddle SJH, Mutrie N. Psychology of physical activity: Determinants,
well-being, and interventions (2001) London: Routledge.
Biddle SJH, Sallis J, Cavill N. Young and active? Young people and
health-enhancing physical activity: Evidence and implications (1998) London:
Health Education Authority.
Braet C, Mervielde I, Vandereycken W. Psychological aspects of childhood
obesity: A controlled study in a clinical and nonclinical sample. Journal of
Pediatric Psychology (1997) 22:59–71.
Casper RC, Offer D. Weight and dieting concerns in adolescents, fashion or
symptom? Pediatrics (1990) 86:384–390.
Cole TJ, Faith MS, Pietrobelli A, Heo M. What is the best measure of
adiposity change in growing children: BMI, BMI%, BMI z-score or BMI centile?
European Journal of Clinical Nutrition (2005) 59:419–425.
Crocker PR, Eklund RC, Kowalski KC. Children's physical activity and
physical self-perceptions. Journal of Sports Sciences (2000) 18:383–394.
Crocker P, Sabiston C, Forrestor S, Kowalski N, Kowalski K, McDonough M.
Predicting change in physical activity, dietary restraint, and physique
anxiety in adolescent girls: Examining covariance in physical
self-perceptions. Canadian Journal of Public Health (2003) 94:332–337.
Dietz WH. Health consequences of obesity in youth: Childhood predictors of
adult disease. Pediatrics (1998) 101:518–525.
Dietz WH, Gortmaker SL. Do we fatten our children at the television set?
Obesity and television viewing in children and adolescents. Pediatrics
(1985) 75:807–812.
Dishman RK. Increasing and maintaining exercise and physical activity.
Behavior Therapy (1991) 22:345–378.
Durant RH, Baranowski T, Johnson M, Thompson WO. The relationship among
television watching, physical activity, and body composition of young
children. Pediatrics (1994) 94:449–455.
Eisenberg ME, Neumark-Sztainer D, Story M. Associations of weight-based
teasing and emotional well-being among adolescents. Archives of Pediatrics &
Adolescent Medicine (2003) 157:733–738.
Ekeland E, Heian F, Hagen KB, Abbott J, Nordheim L. Exercise to improve
self-esteem in children and young people (Cochrane Review). In: The Cochrane
Library (2004) Chichester, UK: John Wiley and Sons, Ltd. 1–30.
Eklund RC, Whitehead JR, Welk GJ. Validity of children and youth physical
self-perception profile: A confirmatory factor analysis. Research Quarterly
for Exercise and Sport (1997) 68:249–256.
Epstein LH, Roemmich JN, Paluch RA, Raynor HA. Physical Activity as a
substitute for sedentary behavior in youth. Annals of Behavioral Medicine
(2005) 29:200–209.
Fairburn CG, Welch SL, Doll HA, Davies BA, O'Connor ME. Risk factors for
bulimia nervosa. A community-based case-control study. Archives of General
Psychiatry (1997) 54:509–517.
Faith MS, Berman N, Heo M, Pietrobelli A, Gallagher D, Epstein LH, et al.
Effects of contingent television on physical activity and television viewing
in obese children. Pediatrics (2001) 107:1043–1048.
Field AE, Austin SB, Taylor CB, Malspeis S, Rosner B, Rockett HR, et al.
Relation between dieting and weight change among preadolescents and
adolescents. Pediatrics (2003) 112:900–906.
Field AE, Camargo, C. A. Jr, Taylor CB, Berkey CS, Frazier AL, Gillman MW,
et al. Overweight, weight concerns, and bulimic behaviors among girls and
boys. Journal of the American Academy of Child & Adolescent Psychiatry
(1999) 38:754–760.
Fox KR, Corbin CB. The Physical Self-Perception Profile: Development and
preliminary validation. Journal of Sport and Exercise Psychology (1989)
11:408–430.
French SA, Jeffery RW, Forster JL, McGovern PG, Kelder SH, Baxter JE.
Predictors of weight change over two years among a population of working
adults: The Healthy Worker Project. International Journal of Obesity &
Related Metabolic Disorders (1994) 18:145–154.
French SA, Perry CL, Leon GR, Fulkerson JA. Self-esteem and change in body
mass index over 3 years in a cohort of adolescents. Obesity Research (1996)
4:27–33.
French SA, Story M, Perry CL. Self-esteem and obesity in children and
adolescents: A literature review. Obesity Research (1995) 3:479–490.
Goldfield GS, Kalakanis LE, Ernst MM, Epstein LH. Open-loop feedback to
increase physical activity in obese children. International Journal of
Obesity & Related Metabolic Disorders (2000) 24:888–892.
Goldfield GS, Mallory R, Parker T, Cunningham T, Legg C, Lumb A, et al.
Effects of open-loop feedback on physical activity and television viewing in
overweight and obese children: A randomized controlled trial. Pediatrics
(2006) 118:e157–e166.
Goodman E, Whitaker RC. A prospective study of the role of depression in the
development and persistence of adolescent obesity. Pediatrics (2002)
110:497–504.
Gortmaker SL, Must A, Perrin JM, Sobol AM, Dietz WH. Social and economic
consequences of overweight in adolescence and young adulthood. New England
Journal of Medicine (1993) 329:1008–1012.
Gortmaker SL, Must A, Sobol AM, Peterson K, Colditz GA, Dietz WH. Television
watching as a cause of increasing obesity among children in the United
States, 1986–1990. Archives of Pediatrics and Adolescent Medicine (1996)
150:356–362.
Gruber J. Physical activity and self-esteem development in children: A
meta-analysis. In: Effects of physical activity on children—Stull G, Eckern
H, eds. (1986) Champaign, IL: Human Kinetics. 330–348.
Hancox RJ, Poulton R. Watching television is associated with childhood
obesity: But is it clinically important? International Journal of Obesity
(2006) 30:171–175.
Harter S. Manual for the self-perception profile for children (1985) Denver:
University of Denver.
Janssen I, Katzmarzyk PT, Boyce WF, Vereecken C, Mulvihill C, Roberts C, et
al. Comparison of overweight and obesity prevalence in school-aged youth
from 34 countries and their relationships with physical activity and dietary
patterns. Obesity Reviews (2005a) 6:123–132.
Janssen I, Katzmarzyk PT, Srinivasan SR, Chen W, Malina RM, Bouchard C, et
al. Utility of childhood BMI in the prediction of adulthood disease:
Comparison of national and international references. Obesity Research
(2005b) 13:1106–1115.
Johnson MS, Figueroa-Colon R, Herd SL, Fields DA, Sun M, Hunter GR, et al.
Aerobic fitness, not energy expenditure, influences subsequent increase in
adiposity in black and white children. Pediatrics (2000) 106:E50–E56.
Kirkcaldy BD, Shephard RJ, Siefen RG. The relationship between physical
activity and self-image and problem behaviour among adolescents. Social
Psychiatry & Psychiatric Epidemiology (2002) 37:544–550.
Kuczmarski RJ, Ogden CL, Guo SS, Grummer-Strawn LM, Flegal KM, Mei Z, Wei R,
Curtin LR, Roche AF, Johnson CL. 2000 CDC growth charts for the United
States: Methods and development. Vital Health Statistics (2002) 246:1–190.
Latner JD, Stunkard AJ. Getting worse: The stigmatization of obese children.
Obesity Research (2003) 11:452–456.
Mamalakis G, Kafatos A, Manios Y, Anagnostopoulou T, Apostolaki I. Obesity
indices in a cohort of primary school children in Crete: A six year
prospective study. International Journal of Obesity & Related Metabolic
Disorders (2000) 24:765–771.
Norman GJ, Schmid BA, Sallis JF, Calfas KJ, Patrick K. Psychosocial and
environmental correlates of adolescent sedentary behaviors. Pediatrics
(2005) 116:908–916.
Olds T, Ridley K, Dollman J. Screenieboppers and extreme screenies: The
place of screen time in the time budgets of 10–13 year old Australian
children. Australian and New Zealand Journal of Public Health (2006)
30:137–142.
Pate RR, Pratt M, Blair SN, Haskell WL, Macera CA, Bouchard C, et al.
Physical activity and public health: A recommendation from the Centers for
Disease Control and Prevention and the American College of Sports Medicine.
Journal of the American Medical Association (1995) 273:402–407.
Pierce JW, Wardle J. Cause and effect beliefs and self-esteem of overweight
children. Journal of Child Psychology & Psychiatry & Allied Disciplines
(1997) 38:645–650.
Premack D. Toward empirical behavioral laws: 1. Positive reinforcement.
Psychological Review (1959) 66:219–233.
Puhl R, Brownell KD. Bias, discrimination, and obesity. Obesity Research
(2001) 9:788–805.
Raudsepp L, Liblik R. Relationship of perceived and actual motor competence
in children. Perceptual & Motor Skills (2002) 94:1059–1070.
Rhee H, Holditch-Davis D, Miles MS. Patterns of physical symptoms and
relationships with psychosocial factors in adolescents. Psychosomatic
Medicine (2005) 67:1006–1012.
Ricciardelli LA, McCabe MP. Children's body image concerns and eating
disturbance: A review of the literature. Clinical Psychology Review (2001)
21:325–344.
Rotenberg KJ, McDougall P, Boulton MJ, Vaillancourt T, Fox C, Hymel S.
Cross-sectional and longitudinal relations among peer-reported
trustworthiness, social relationships, and psychological adjustment in
children and early adolescents from the United Kingdom and Canada. Journal
of Experimental Child Psychology (2004) 88:46–67.
Rowland TW, Freedson PS. Physical activity, fitness and health in children:
A closer look. Pediatrics (1994) 93:669–672.
Rowlands AV, Eston RG, Ingledew DK. Measurement of physical activity in
children with particular reference to the use of heart rate and pedometry.
Sports Medicine (1997) 24:258–272.
Saelens BE, Epstein LH. Behavioral engineering of activity choice in obese
children. International Journal of Obesity (1998) 22:275–277.
Sallis JF, Simons-Morton BG, Stone EJ, Corbin CB, Epstein LH, Faucette N, et
al. Determinants of physical activity and interventions in youth. Medicine
and Science in Sports and Exercise (1992) 24:S248–S257.
Shunk JA, Birch LL. Girls at risk for overweight at age 5 are at risk for
dietary restraint, disinhibited overeating, weight concerns, and greater
weight gain from 5 to 9 years. Journal of the American Dietetic Association
(2004) 104:1120–1126.
Stark O, Atkins E, Wolff OH, Douglas JWB. Twenty-four hour energy
expenditure and resting metabolic rate in obese, moderately obese, and
control subjects. American Journal of Clinical Nutrition (1981) 35:566–573.
Swallen KC, Reither EN, Haas SA, Meier AM. Overweight, obesity, and
health-related quality of life among adolescents: The National Longitudinal
Study of Adolescent Health. Pediatrics (2005) 115:340–347.
The Annenberg Public Policy Center of the University of Pennsylvania.
Television in the home: The 1997 Survey of Parents and Children (1997)
Philadelphia: University of Pennsylvania.
Tremblay MS, Willms JD. Secular trends in the body mass index of Canadian
children. CMAJ (2000) 163:1429–1433.
Viner RM, Cole TJ. Television viewing in early childhood predicts adult body
mass index. Journal of Pediatrics (2005) 147:429–435.
Wardle J, Cooke L. The impact of obesity on psychological well-being. Best
Practice & Research Clinical Endocrinology & Metabolism (2005) 19:421–440.
Welk G, Blair S, Wood K, Jones S, Thompson R. A comparative evaluation of
three accelerometry-based physical activity monitors. Medicine and Science
in Sports and Exercise (2000) 32(9 Suppl):S489–S497.
Weston AT, Petosa R, Pate RR. Validation of an instrument for measurement of
physical activity in youth. Medicine and Science in Sports and Exercise
(1997) 29:138–143.
World Health Organization. Controlling the global obesity epidemic. (2002)
http://www.who.int/nut/obs.html.
Zeller MH, Saelens BE, Roehrig H, Kirk S, Daniels SR. Psychological
adjustment of obese youth presenting for weight management treatment.
Obesity Research (2004) 12:1576–1586.
Acknowledgements
The authors would like to thank Dr Hollie Raynor, and Paula Cloutier for
providing constructive feedback on previous versions of this manuscript.

Funding Information
This research is supported, in part, by a New Investigator Award and
clinical trial grant from the Canadian Institutes of Health Research (CIHR)
awarded to Dr Gary Goldfield.

Reprint Address
Gary S. Goldfield, PhD, C. Psych, Senior Investigator, Children's Hospital
of Eastern Ontario Research Institute, Mental Health Research, 401 Smyth
Rd., Ottawa, ON Canada K1H 8L1. E-mail: ggoldfield@...


Gary S. Goldfield, PhD,1,2,3,4 Risa Mallory, MEd,1 Torrey Parker, MSc,2
Terrell Cunningham, BA,4 Christine Legg, BA,4 Andrew Lumb, BA,4 Kasey
Parker,2 Denis Prud'homme, MD, MSc2 and Kristi B. Adamo, PhD2,3,5

1Mental Health Research, Children's Hospital of Eastern Ontario Research
Institute,
2School of Human Kinetics, University of Ottawa,
3Department of Paediatrics, University of Ottawa,
4Department of Psychology, Carleton University, and
5Chalmers Research Group, Children's Hospital of Eastern Ontario Research
Institute

Conflict of interest: None declared.