Protective effect of physical activity on dissatisfaction with body image in children – A cross-sectional study

Psychology of Sport and Exercise 12 (2011) 563e569

Contents lists available at ScienceDirect

Psychology of Sport and Exercise journal homepage: www.elsevier.com/locate/psychsport

Protective effect of physical activity on dissatisfaction with body image in children e A cross-sectional study Marisa J. Monteiro Gaspar a, Teresa F. Amaral a, b, *, Bruno M.P.M. Oliveira a, c, Nuno Borges a a

Faculdade de Ciências da Nutrição e Alimentação da Universidade do Porto, Porto, Portugal UISPA Porto, Porto, Portugal c LIAADeINESC Porto LA, Porto, Portugal b

a r t i c l e i n f o

a b s t r a c t

Article history: Received 29 June 2010 Received in revised form 11 May 2011 Accepted 14 May 2011 Available online 26 May 2011

Objective: To evaluate, in pre-adolescents and adolescents, the frequency of body image dissatisfaction and distortion and to assess the association between these factors and physical activity and body mass index (BMI). Design: Cross-sectional study. Methods: 234 children (10e17 years) from a Porto high school were evaluated. Dissatisfaction with body image (FID) was assessed by Collins’ child figure drawings for pre-adolescents and adolescents. FID was calculated as the discrepancy between the “ideal figure” and the “perceived figure”. Body image distortion (BID) was calculated as the discrepancy between the “perceived figure” and the “real figure”. The Baecke questionnaire was applied to determine the habitual physical activity index (HPAI) of each participant. Results: Girls were more dissatisfied than boys with their body image (68.1% vs 52.9%). A high proportion of students of both genders and age groups revealed BID (71.8%) with 51.3% underestimating their body image and 20.5% overestimating it. A negative association was found between the FID and BID (girls: r ¼ .259, p ¼ .006; boys: r ¼ .414, p < .001). High levels of physical activity were associated with a protective effect on FID, OR ¼ 0.38, 95% CI [0.16, 0.87] for 3rd vs 1st quartile of HPAI; OR ¼ 0.29, 95% CI [0.12, 0.86], for 4th vs 1st quartile of HPAI, both adjusted for BMI and gender, but HPAI was not associated with BID. Conclusion: FID and BID are highly frequent and inversely associated. BID increases directly with BMI percentiles in both genders while physical activity has a protective effect on dissatisfaction of body image. Ó 2011 Elsevier Ltd. All rights reserved.

Keywords: Body image dissatisfaction Adolescence BMI percentile Habitual physical activity index

An accurate body image perception is crucial for the way children and adolescents develop a healthy relationship with their bodies and food intake behaviour (Strauss, 1999). Individual perception of body image varies throughout life, probably due to the physical changes that occur during growth (Young-Hyman, Schlundt, Herman-Wenderoth, & Bozylinski, 2003). The awareness of these changes as well as increasing cognitive knowledge and personal introspection may make the child or adolescent, who is concerned with body image, more susceptible to poor body image perception (Young-Hyman et al., 2003). The assessment of body image perception is useful to know how the subject compares himself to a body picture or is able to recognise his build among

* Corresponding author. Faculdade de Ciências da Nutrição e Alimentação da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. E-mail address: [email protected] (T.F. Amaral). 1469-0292/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.psychsport.2011.05.004

several pictorial representations (Sobral & Vasconcelos, 1996). It allows the quantification of an important dimension of body image related to the attitudes and evaluations of one’s own body: the dissatisfaction with body image, which is and can be defined as a negative self-evaluation (Barker & Galambos, 2003). Dissatisfaction is frequently measured as the discrepancy between the perceived and the ideal figure. The assessment of body image perception also allows the identification of another important component, the body image distortion which is evaluated by the discrepancy between the perceived figure and the actual body dimensions and obtained by anthropometrical measurements. Although body image distortion is known as an important dimension of body image, only a few reports have evaluated it among the community of children and adolescents (and different methodological approaches were used). Gualdi-Russo et al. (2008) evaluated the discrepancy between self-figure perception in overweight subjects who chose more than two figures away from the

564

M.J. Monteiro Gaspar et al. / Psychology of Sport and Exercise 12 (2011) 563e569

correct figure on Collins’ (1991) scale. The underestimation of the real figure occurred respectively in 6% and 9% of the overweight or obese children (Gualdi-Russo et al., 2008). Other reports were based on the discrepancy between perceived and actual body mass index (BMI) classes. A study conducted in low-income urban African American adolescents revealed a high frequency of body image distortion with 27.2% underestimating and 5.6% overestimating their own body mass index status (Wang, Liang, & Chen, 2009). A report from Malaysia showed higher discrepancies between body weight perception and BMI categories; 34.5% of underweight males and 20.5% of the females perceived themselves as having a normal weight and about a quarter of the overweight males and females also perceived that they had a normal weight. A recent report also showed that body image distortion was highly prevalent among non-overweight girls in the USA, with 12.4% underestimating and 28.8% overestimating actual BMI status, which was recently identified as risk factor for unsafe weight loss methods (Liechty, 2010). Body image distortion implies large cognitive distress and is associated with anorexia and other eating disorders (Schneider, Frieler, Pfeiffer, Lehmkuhl, & Salbach-Andrae, 2009). Dissatisfaction with body image may adversely affect the physical and psychological well-being and is also associated with the aetiology of many eating disorders such as bulimia, anorexia and binge eating (Barker & Galambos, 2003; Beato, RodríguezCano, Belmonte-Llario, & Martínez-Delgado, 2004; Khor, Zalilah, & Phan, 2009; Sepulveda, Carrobles, Gandarillas, Poveda, & Pastor, 2007). It was recently shown that body image dissatisfaction was strongly related to poor nutritional and physical activity habits and also with unsafe weight management practices among African American adolescents (Wang et al., 2009). Furthermore, dissatisfaction was associated with a low self-esteem (Van den Berg, Mond, Eisenberg, Ackard, & Neumark-Sztainer, 2010), high incidence of depression (Friedman & Brownell, 1995; Pimenta, Sánchez-Villegas, Bes-Rastrollo, López, & Martínez-González, 2009; Stice, Hayward, Cameron, Killen, & Taylor, 2000) and suicide attempts among adolescents (Kim & Kim, 2009). Gender, age and ethnicity are factors that influence the association between overweight/obesity and dissatisfaction with body image (Olvera, Suminski, & Power, 2005; Stockton et al., 2009; Zaborskis, Petronyte, Sumskas, Kuzman, & Iannotti, 2008). Dissatisfaction among normal weight adolescents has two distinct features, boys express the desire to have a bigger build, while girls wish to be thinner (Khor et al., 2009; Mellor et al., 2007; Zaborskis et al., 2008). Compared with normal weight individuals, adolescents at risk of being overweight or who are overweight shows high levels of dissatisfaction with body image. Both genders, in general, express a desire to be thinner (Paxton, Eisenberg, & NeumarkSztainer, 2006; Sepulveda, Carrobles, & Gandarillas, 2008; Zaborskis et al., 2008). Differences in body image dissatisfaction between genders have been described since the early stages of adolescence, with girls being more dissatisfied with their body image than boys (Al Sabbah et al., 2009; Olvera et al., 2005; Stockton et al., 2009). Data from the Pittsburgh Girls Study revealed that even at a young age, 35% of nine year olds and 38% of ten year olds showed dissatisfaction with their bodies (Deleel, Hughes, Miller, Hipwell, & Theodore, 2009). Even when girls are of normal weight or are underweight, they feel fat or out of proportion and therefore present a distorted body image (Khor et al., 2009). The gender discrepancy in regards to dissatisfaction with body image increases with age, the dissatisfaction among girls rises while remaining constant among boys (Olvera et al., 2005). With regard to ethnicity, studies show that white adolescents tend to be more dissatisfied with their body image when compared with black adolescents (Baecke, Burema, & Frijters, 1982; Mciza et al., 2005).

It is proven that regular physical activity brings many benefits to physical and psychological level, such as decreased risk of cardiovascular disease, type 2 diabetes mellitus, hypertension, different types of cancer, osteoporosis, anxiety and depression (Pan et al., 2009; Warburton, Nicole, & Bredin, 2006). Some evidence also exists showing that regular physical activity and sport have a beneficial effect on body image perception among children and adolescents. Playing sport in adolescence is related to a positive effect on perception of body image and self-esteem, decreasing the incidence of depression (Kircaldy, Shephard, & Siefen, 2002; Moreno, Cervelló, & Moreno, 2008). After six weeks of aerobic dance training it was found that dissatisfaction with body image was reduced among adolescent girls (Burgess, Grogan, & Burwitz, 2006). Moreover, dissatisfaction with body image may be the reason for choosing physical activity and exercise as a strategy for obtaining the optimal image, especially in adolescent girls (McCabe & Ricciardelli, 2004; Smith, Handley, & Eldredge, 1998). Inversely, dissatisfaction with body image was also related with less engagement in physical activities (Jensen & Steele, 2009). These studies unequivocally document a growing body of evidence linking the benefits of physical activity to lower body image dissatisfaction in children and adolescents (Burgess et al., 2006; Kircaldy et al., 2002; Moreno et al., 2008). Nevertheless, the association between physical activity and body image dissatisfaction has not been properly quantified yet, as previous research was conducted amongst specific age or gender subgroups (Burgess et al., 2006; Kircaldy et al., 2002; Moreno et al., 2008). Moreover, BMI categories have different effects upon the way children and adolescents perceive their body image and their levels of dissatisfaction. Consequently, the BMI of each child or adolescent will influence the way he or she deals with image dissatisfaction and the practices they adopt to change body image, including physical activity strategies. Therefore, a possible protective effect of physical activity on body image dissatisfaction needs to be properly quantified, taking into consideration the effect of BMI. According to our knowledge, a possible protective effect of physical exercise on body image distortion has also not been studied yet and its study is also of foremost interest. So, we hypothesized that physical activity has a protective effect in both body image dissatisfaction and distortion, independent of other factors, such as age, gender and BMI. The aims of this study were to evaluate the frequency of body image dissatisfaction and distortion and to assess the association between the physical activity and BMI with both body image dissatisfaction and distortion in pre-adolescents and adolescents. Method Participants This is a cross-sectional study conducted at a secondary school in Porto, Portugal, in 2008. A stratified sampling was carried out among 711 students spread over five academic years. In each year one third of the classes were selected based on timetable convenience and a total of 261 students were recruited. Of the students recruited, 234 agreed to participate in the study (51.7% boys and 48.3% girls, aged between 10.3 and 17.7 years). Each student’s anthropometric measurements, assessment of perception of body image and physical activity components were evaluated by trained interviewers. The interviewers were trained previously to obtain the different components of this evaluation. Detailed information about the theoretical background and about how to retrieve data was provided. Training was continued until the interviewers were able to correctly undertake data collection and consistency between interviewers was achieved.

M.J. Monteiro Gaspar et al. / Psychology of Sport and Exercise 12 (2011) 563e569

565

According to the Declaration of Helsinki (Declaration of Helsinki e Ethical Principles for Medical Research Involving Human Subject, 2011), all students were invited to participate in this study and a written explanation form setting out the aims and study procedures was given to them. Parents were asked if they agreed to let the students participate in the study and if so gave written informed consent. All students whose parents agreed to take part in the study were also asked by the interviewer if they would like to participate. They were also informed about the right to refuse to participate in the study or to give up at any moment, without any consequences. Positive informed consent from both parents and children was an inclusion criterion for the study.

established, and was considered the “real figure”. Each figure (F1eF7) corresponds to an interval in PcBMI: F1 if PcBMI < 10, F2 if PcBMI in [10; 25[, F3 if PcBMI in [25; 50[, F4 if PcBMI in [50; 75[, F5 if PcBMI in [75; 85[, F6 if PcBMI in [85; 95[ and F7 if PcBMI  95. We also evaluated BID in risk of overweight/overweight subjects by the method described by Gualdi-Russo et al. (2008), in order to make possible comparisons with this previously published data. The perception of body image was identified as inappropriate or wrong according to the following general scheme for Collins (1991) figures: F1 e wrong; F2 e wrong; F3 e inadequate, F4 e acceptable; F5 e acceptable; F6 e correct; F7 e correct (Gualdi-Russo et al., 2008).

Anthropometric measurements

Physical activity

Anthropometric assessment of each student was based on the methodologies and techniques described by Jelliffe and Gibson (Gibson, 2005; Jelliffe & Jelliffe, 1989). Height was determined with a Siber-HegnerÒ stadiometer, with a resolution of 0.1 cm and weight was measured with a SoehnleÒ scale with a resolution of 0.1 kg. Quetelet index (BMI) was calculated (weight/height2), which was later converted to percentile of BMI (PcBMI) and BMI z-score, using reference tables from the Centres for Disease Control and Prevention as well as categories names (2000 CDC Growth Charts). Students were categorized according to the cut offs of gender and age specific BMI percentiles (2000 CDC Growth Charts) in low weight (PcBMI < 5), normal weight (5  PcBMI < 85), risk of overweight (85  PcBMI < 95) and overweight (PcBMI  95).

The assessment of habitual physical activity index (HPAI) of each participant was made through the Baecke questionnaire (Baecke et al., 1982). This scale consists of sixteen questions that allow the evaluation of three Physical Activity Indexes (PAI): occupational PAI, sport PAI and leisure PAI. The total of these three PAI indexes gives the HPAI. This scale was validated among Dutch individuals of both sexes, aged between 19 and 32 years. The testeretest reliability of the PAI indexes was measured with an interval of 3 months and ranged between .80 and .90 for the occupational PAI and sport PAI, and .74 for leisure PAI (Baecke et al., 1982). This scale was also validated in Portuguese adolescents using a 24-h recall instrument of the daily activities as reference method. The results showed correlation coefficients ranging from .55 to .85 in girls and .69 to .82 in boys (Guedes, Lopes, Guedes, & Stanganell, 2006). Regarding the first Baecke questionnaire question, “What is your main occupation”, we considered that all subjects had a low occupation PAI level, as they were all school students.

Body image dissatisfaction The perception of body image was assessed using a Collins’ Child Figure Drawings scale of a body silhouette drawn for preadolescents and adolescents, consisting of seven pictures of children and adolescents of both sex, ordered sequentially from the thinness (F1) to obesity (F7) (Collins, 1991). The scale used was previously validated in 1990 among 1118 pre-adolescents in India, with testeretest reliability coefficients for figure selection as follows: “perceived figure” ¼ .71; “ideal figure” ¼ .59. Validity coefficients were “perceived figure” and weight ¼ .36; “perceived figure” and BMI ¼ .37 (Collins, 1991). After observing the respective figures, each participant was asked: “Which of these silhouettes do you consider to be similar to your own image?” This image was considered as “perceived figure”. The second question asked “which of these silhouettes represents the figure you would like to have?” This image was considered as the “ideal figure”. The difference between the “perceived figure” and the “ideal figure” was computed, revealing the degree of dissatisfaction with body image (FID or Feel minus Ideal Discrepancy) (Mciza et al., 2005). A positive FID value indicates that the “perceived figure” is higher than the “ideal figure” and a negative value of FID means that the “perceived figure” is lower than the “ideal figure”. A FID value equal to 0 means that there are no discrepancies, i.e. the “perceived figure” is equal to the “ideal figure”. It was considered that each participant was satisfied with their body image if FID ¼ 0 and dissatisfied otherwise (if FID  1 or if FID  1). Body image distortion To assess discrepancy between self-figure perception and the real nutritional status, body image distortion was calculated as BID ¼ “perceived figure”  “real figure”. To our knowledge there are no previous reports on BID for all BMI classes based on figures. The connection between BMI percentile and a body silhouette was

Statistical analysis Means and standard deviations were calculated for the quantitative and continua variables. The normal distribution of the variables was tested using the KolmogoroveSmirnov test. The Student’s t-test was used for comparing means between two groups, the ManneWhitney test was used for comparing mean ranks between two groups, the Wilcoxon test was used for comparing mean ranks of paired variables and the KruskaleWallis test was used to compare mean ranks between three or more groups. To compare the mean ranks of three (or more) paired variables the Friedman test was used. The Spearman correlation was used to analyse the association between BMI percentile, FID, BID and HPAI. Two logistic regression models were used to evaluate the association of HPAI with dissatisfaction with body image or distortion of body image, adjusted for gender and BMI percentile. Odds ratios (OR) and respective 95% confidence intervals (95% CI) estimates were carried out. FID and BID prediction according to BMI z-score and HPAI was done through linear regression. All tests were considered significant if p value < .05. We used Cohen’s d to evaluate the effect size. PASWÒ software version 18.0 was used for statistical analysis. Results Table 1 presents the anthropometric characteristics of our sample, namely height, weight, BMI z-score, “perceived figure”, “ideal figure”, “real figure”, body image dissatisfaction, body image distortion, occupational, sports and leisure PAI and HPAI for both genders, according to age. The frequency of overweight among participants between 10 and 12 years was 20.3% in boys and 9.2% in girls. From 13 to 17 years, 10.6% of boys and 13.5% of girls were overweight. Most girls were dissatisfied with their body image

566

M.J. Monteiro Gaspar et al. / Psychology of Sport and Exercise 12 (2011) 563e569

Table 1 Sample characteristics by gender and age. Boys (n ¼ 121)

Girls (n ¼ 113)

10e12 Years (n ¼ 74) 13e17 Years (n ¼ 47) Test

p*

M

SD

M

SD

44.19 1.47 0.64

11.21 0.09 0.95

56.36 1.65 0.16

12.79 0.11 1.13

Body image Perceived figure 4.09 3.65 Ideal figure Real figure 4.69 FID 0.45 BID 0.59

0.94 0.80 1.65 1.01 1.25

3.45 3.34 3.91 0.11 0.47

0.90 0.56 1.82 0.96 1.35

U ¼ 1099.5 U ¼ 1249.0 U ¼ 1313.5 U ¼ 1470.0 U ¼ 1651.5

<.001 .004 .02 .13 .63

PAI Occupational Sport Leisure

2.03 2.83 2.38

0.40 1.62 0.66

2.08 2.45 2.23

0.40 1.55 0.62

U ¼ 1608.5 U ¼ 1467.5 U ¼ 1486.0

HPAI

7.24

1.89

6.76

1.73

U ¼ 1453.0

Anthropometrics Weight (kg) Height (m) BMI z-score

Effect size

10e12 Years (n ¼ 76) 13e17 Years (n ¼ 37) Test

p*

Effect size

M

SD

M

SD

45.75 1.49 0.60

9.74 0.08 0.89

58.33 1.60 0.64

11.01 0.06 0.91

.032 4.30 .36 3.62 .38 4.59 .42 0.68 .48 0.29

0.91 0.67 1.56 0.87 1.06

3.84 3.38 4.76 0.46 0.92

0.96 0.55 1.67 0.90 1.44

U ¼ 1007.0 U ¼ 1106.0 U ¼ 1303.0 U ¼ 1279.5 U ¼ 1037.5

.009 .04 .52 .403 .02

.36 .39 .46 .46 .37

.49 .15 .18

.46 .42 .43

2.00 1.81 2.31

0.38 1.20 0.56

2.07 2.82 2.36

0.41 2.04 0.52

U ¼ 1268.0 U ¼ 992.0 U ¼ 1282.0

.38 .01 .44

.45 .35 .46

.13

.42

6.13

1.49

7.24

2.27

U ¼ 986.5

.01

.35

t(119) ¼ 5.51 <.001 1.04 t(119) ¼ 9.68 <.001 1.83 t(119) ¼ 2.55 .01 .48

t(111) ¼ 6.17 <.001 1.24 t(111) ¼ 6.83 <.001 1.37 t(111) ¼ 0.23 .82 .05

Note. SD ¼ Standard deviation; BMI ¼ body mass index; FID ¼ feel minus ideal discrepancy; BID ¼ body image distortion; PAI ¼ physical activity index; HPAI ¼ habitual physical activity index. *p e Significance level for comparing in each gender, the group of 10e12 years with the group of 13e17 years, using the ManneWhitney test.

(68.1%), while 8.8% considered the “perceived figure” lower than the “ideal figure” and 59.3% believed that their “perceived figure” was higher than the “ideal figure”. A lower proportion of boys were dissatisfied with their body image (52.9%), while 16.7% revealed that their “perceived figure” is lower than the “ideal figure” and 36.2% considered their “perceived figure” higher than the “ideal figure”. Concerning FID, no differences with statistical significance between the two age groups within each gender were found. In contrast, girls had a higher body image dissatisfaction than boys (ManneWhitney Z ¼ 2.986, p ¼ .003). The difference between the order of the “perceived” and “ideal” figures is significant in both genders (Wilcoxon test: Z ¼ 6.208, p < .001 for girls and Z ¼ 3.202, p ¼ .001 for boys). With regards to BID, older girls had higher distortions. Furthermore, most girls had distortion of their body image (70.8%), with 51.3% underestimating their body image and 19.5% overestimating it (Table 1). For boys, no age differences were found for BID. Most showed BID (72.7%); of these, 51.2% underestimated and 21.5% overestimated it. No differences with statistical significance were found between the genders. A negative association was found between FID and BID (girls: r(111) ¼ .198, p ¼ .035, boys: r(119) ¼ .416, p < .001). Results for “real image”, “perceived image” and “ideal image” were compared and showed statistically significant differences

both within boys and within girls (Friedman test: c2(235) ¼ 65.76, p < .001 and c2(235) ¼ 22.33, p < .001, respectively). Table 2 shows body image dissatisfaction and distortion according to BMI percentile-based classes. Adolescents who were at risk of overweight or were overweight demonstrated a high degree of dissatisfaction with their body image. Of these, 70.6% of boys and 87.1% of girls at risk of overweight and 90% of boys and 91.7% of overweight girls were dissatisfied with their body image. However, 18.8% of boys and 44.8% of the normal weight girls were also dissatisfied with their body image and wished to be thinner (FID  1). Furthermore, 21.3% of boys and 13.4% of normal weight girls expressed the desire to have a bigger build (FID  1). There is a moderate correlation between the FID and the percentile of BMI in both genders (boys: r(119) ¼ .698, p < .001, girls: r(111) ¼ .582, p < .001). Adolescents who were at risk of being overweight or were overweight were shown to have the highest levels of body image distortion (Table 2). Most students at risk of overweight (96.8% of girls and 94.1% of boys) underestimated their body image and all boys and girls with overweight underestimated it. However, 23.9% of girls and 32.5% of boys in the normal weight BMI class also underestimated their body image. There is a negative correlation between the body image distortion and the BMI percentile in both genders (girls: r(111) ¼ .791, p < .001; boys: r(119) ¼ .804, p < .001). Using the Gualdi-Russo classification (Gualdi-Russo et al.,

Table 2 Body image dissatisfaction (FID) and distortion (BID) according to BMI percentile-based classes. Boys (n ¼ 121)

BMI classification Underweight Normal Overweight risk Overweight Underweight Normal Overweight risk Overweight

Girls (n ¼ 113)

FID  1 n (%)

FID ¼ 0 n (%)

FID  1 n (%)

2 (50.0) 17 (21.3) 1 (5.9) 0 (0.0)

2 48 5 2

0 (0.0) 15 (18.8) 11 (64.7) 18 (90.0)

BID  1 n (%) 0 (0.0) 26 (32.5) 16 (94.1) 20 (100.0)

BID ¼ 0 n (%) 0 (0.0) 33 (41.3) 0 (0.0) 0 (0.0)

(50.0) (60.0) (29.4) (10.0)

BID  1 n (%) 4 (100.0) 21 (26.3) 1 (5.9) 0 (0.0)

Note. BMI ¼ body mass index; FID ¼ feel minus ideal discrepancy; BID ¼ body image discrepancy.

FID  1 n (%) 0 (0.0) 9 (13.4) 1 (3.2) 0 (0.0) BID  1 n (%) 0 (0.0) 16 (23.9) 30 (96.8) 12 (100.0)

FID ¼ 0 n (%)

FID  1 n (%)

3 28 4 1

0 (0.0) 30 (44.8) 26 (83.9) 11 (91.7)

(100.0) (41.8) (12.9) (8.3)

BID ¼ 0 n (%) 0 (0.0) 32 (47.8) 1 (3.2) 0 (0.0)

BID  1 n (%) 3 (100.0) 19 (28.4) 0 (0.0) 0 (0.0)

M.J. Monteiro Gaspar et al. / Psychology of Sport and Exercise 12 (2011) 563e569

2008), an inadequate body image perception was shown by 28.2% of the girls and 15.9% of the boys at the risk of overweight and overweight. For physical activity, there were no statistically significant differences between younger boys and older boys for the HPAI. Otherwise, girls from 13 to 17 years have a higher HPAI than the younger girls (t(111) ¼ 2.700, p ¼ .010). With regards to gender differences, it is noted that boys had a higher HPAI ¼ 7.05 (SD ¼ 1.84) than girls HPAI ¼ 6.50 (SD ¼ 1.85), this difference being statistically significant (t(232) ¼ 2.311, p ¼ .003). The Spearman correlation between BMI percentile and HPAI shows that the association between these two variables is not statistically significant. The same is observed in the correlation between the BID and HPAI. We related the dissatisfaction (FID s 0) with the HPAI, while adjusting for the percentile of BMI and gender (Table 3). Physical activity has a protective effect on the satisfaction with body image for the 3rd and 4th HPAI quartiles. The effect size for the highest quartile of physical activity in FID has an OR of 0.684. We also observed that participants with higher BMI z-score had higher odds of being dissatisfied. Linear regression was carried out (R ¼ .616, p < .001) to predict the FID as a function of z-score of BMI (standardized coefficient b ¼ .607, p < .001) and HPAI (standardized coefficient b ¼ .108, p < .040). So, it is possible to infer that we have higher FID scores for high z-scores of BMI and low HPAI, hence the desire among the study participants to own a thinner body is higher for those with high BMI and low physical activity. In order to evaluate the effect of HPAI on body image distortion (BID), we attempted to perform a logistic regression similar to the one presented for FID. However, the model failed to converge due to insufficient sample size in some cases. Discussion This study aimed to evaluate the association between the habitual physical activity and BMI with body image dissatisfaction and distortion in pre-adolescents and adolescents. The frequency of body image dissatisfaction was very high, affecting 68.1% of girls and 52.8% of boys from the 234 participants. As described in previous studies (Duncan, Al-Nakeeb, Nevill, & Jones, 2006; Knauss, Paxton, & Alsaker, 2007; Sepulveda et al., 2008; Wang et al., 2009), it was found that girls had higher levels of dissatisfaction with their body image than boys. These results may be explained by the influence of social factors, socio-cultural pressures of the media and also the incessant search for an ideal body that are associated with body dissatisfaction among women (Braga, Molina, & Cade, 2007).

Table 3 Conditional logistic regression model for the association between habitual physical activity index and dissatisfaction with body image (FID s 0). OR Habitual physical activity index 1st Quartile (reference class) 2nd Quartile 3rd Quartile 4th Quartile

1 1.62 0.38 0.29

Body mass index classification Underweight Normal (reference class) Overweight risk Overweight

0.29 1 5.51 15.06

Gender Male (reference class) Female

1 1.65

95% CI

p*

0.68 0.16 0.12

3.85 0.87 0.68

.28 .02 .005

0.05

1.68

.17

2.39 4.19

12.69 54.05

<.001 <.001

0.36

1.23

.15

Note. OR ¼ Odds ratio; CI ¼ confidence interval; FID ¼ Feel minus ideal discrepancy. *p e Significance level.

567

Furthermore, social pressure (McElhone, Kearney, Giachetti, Zunft, & Martínez, 1999), media (McCabe, Ricciardelli, Waga, Goundar, & Fotu, 2009) and the peer group effects (Wang et al., 2009) are stronger and more prescriptive for girls and may be the reason why boys have a lower dissatisfaction with their body image. Adolescents at risk of being overweight or overweight showed high levels of dissatisfaction, with both boys and girls wishing, in general, to be thinner. These findings are consistent with widely described results found in previous studies (Gualdi-Russo et al., 2008; Paxton et al., 2006; Sepulveda et al., 2008). For normal weight adolescents who show dissatisfaction with their body image, it is noteworthy that dissatisfaction among girls and boys follows opposite directions, i.e., the boys expressed the desire to have a bigger build, while girls wished to be thinner. This fact is consistent with data from previously conducted research in which girls idealize lean and slim bodies, while boys crave larger and more muscled bodies (Jones, Fries, & Danish, 2007; Khor et al., 2009; Mellor et al., 2007; Zaborskis et al., 2008). The study by Mellor et al. (2007) showed that, compared to girls, boys suffer from too much pressure exerted by adults, siblings, friends and media to increase muscle mass, while girls are subject to stronger messages from the media for losing weight. Because of perceived differences in body image coveted by both genders, girls and boys adopt different strategies to have the ideal body (Mellor et al., 2007). Girls dissatisfied with their body tend to adopt strategies to lose weight, while the boys adopt strategies to gain weight and muscle mass (Khor et al., 2009; Mellor et al., 2007).We found a high prevalence of body image distortion in both sexes, most frequently shown as an underestimation of body image. Other previous reports showed lower values, but used a different approach relying on the discrepancy between perceived and actual body mass index status (Khor et al., 2009; Liechty, 2010; Wang et al., 2009). Nevertheless, using the methodology previously reported by Gualdi-Russo et al. (2008) for adolescents who were at risk of being overweight or were overweight, our results show that a higher proportion underestimated, and hence distorted, body image, 28.2% of the females and 15.9% of the males, vs respectively 9% and 6%. The relation between body image dissatisfaction and HPAI showed that physical activity may exert a protective effect on satisfaction with body image, for the third and fourth quartile of HPAI. This result is in accordance with previous results from an experimental study conducted in adolescent girls (Burgess et al., 2006), which revealed that after six weeks of aerobic dance training, these girls were able to reduce dissatisfaction with body image and positively increased perception of the body. Also, an investigation conducted by Huang, Norman, Zabinski, Calfas, and Patrick (2007) demonstrated that a behavioural intervention encouraging physical activity and healthy eating habits may be beneficial for teens, including those at excess weight risk or overweight, without adverse consequences on the psychological level of self-body image and self-esteem (Huang et al., 2007). The same study also examined the possibility that girls who lost or maintained weight during six or twelve months, improved satisfaction with their body image (Huang et al., 2007). In contrast, a transversal study conducted by Duncan et al. (2006) among British children aged between 11 and 14 years, showed that physical activity increased dissatisfaction, noting that more active children are more dissatisfied with their body image than inactive children. However, given the cross-sectional nature of this study design, these findings may result from reverse causality. The cross-sectional design of the present study can be regarded as a limitation, not allowing a causal relationship between the habitual physical activity index and dissatisfaction with body image. The absence of the evaluation of the influence of other factors such as ethnicity, socioeconomic factors, the media and peer

568

M.J. Monteiro Gaspar et al. / Psychology of Sport and Exercise 12 (2011) 563e569

groups, on dissatisfaction with body image may represent a further limitation. As literature reports low to moderate levels of association between habitual physical activity assessed by questionnaire and other objective methods, such as accelerometers (Chinapaw, Slootmaker, Schuit, van Zuidam, & van Mechelen, 2009), the use of the Baecke questionnaire (Baecke et al., 1982) to assess physical activity is also acknowledged as weak point of this study. Unlike previous studies that evaluated body image dissatisfaction (Al Sabbah et al., 2009; Niskar, Baron-Epel, Garty-Sadalon, & KeinanBoker, 2009; Wang et al., 2009) this study was not based on selfreported weight and height, which, in this context, can be considered as a strength. A study conducted in adults from the same city of the present study by Ramos, Lopes, Oliveira, and Barros (2009) demonstrated that the use of self-reported height and weight led to an underestimation of the prevalence of obesity; using measured weight and height, the prevalence of obesity in women was 25.3% and when using the self-reported measures, the prevalence was 15%. In conclusion, the present results are in agreement with previous studies, showing that girls are more dissatisfied with their body image than boys. Results also demonstrate that FID and BID are highly frequent and inversely associated. It was also concluded that higher levels of physical activity are associated with a protective effect on dissatisfaction with body image, independent of body mass index or gender. References Al Sabbah, H. A., Vereecken, C. A., Elgar, F. J., Nansel, T., Aasvee, K., Abdeen, Z., et al. (2009). Body weigh dissatisfaction and communication with parents among adolescents in 24 countries: international cross-sectional survey. BMC Public Heath, 9(52). doi:10.1186/1471-2458-9-52. Baecke, J. A. H., Burema, J., & Frijters, J. E. R. (1982). A short questionnaire for the measurement of habitual physical activity in epidemiological studies. The American Journal of Clinical Nutrition, 36(5), 936e942. Barker, E. T., & Galambos, N. L. (2003). Body dissatisfaction of adolescents girls and boys: risk and resource factors. The Journal of Early Adolescence, 23(2), 141e165. doi:10.1177/0272431603023002002. Beato, F. L., Rodríguez-Cano, T., Belmonte-Llario, A., & Martínez-Delgado, C. (2004). Risk factors for eating disorders in adolescents: a Spanish community-based longitudinal study. European Child & Adolescent Psychiatry, 13(5), 287e294. doi:10.1007/500787-004-0407-X. Braga, P. D., Molina, M. C. D., & Cade, N. V. (2007). Expectations of adolescents in relation to changes of nutritional profile. Ciência & Saúde Coletiva, 12(5), 1221e1228. doi:10.1590/S1413-81232007000500019. Burgess, G., Grogan, S., & Burwitz, L. (2006). Effects of a 6-week aerobic dance intervention on body image and physical self-perceptions in adolescent girls. Body Image, 3(1), 57e66. doi:10.1016/j.bodyim.2005.10.005. Chinapaw, M. J., Slootmaker, S. M., Schuit, A. J., van Zuidam, M., & van Mechelen, W. (2009). Reliability and validity of the activity questionnaire for adults and adolescents (AQuAA). BMC Medical Research Methodology, 9, 58. doi:10.1186/ 1471-2288-9-58. 2000 CDC Growth Charts. Use and Interpretation of the CDC Growth Charts - An Instructional Guide, 2010. Collins, M. E. (1991). Body figure perceptions and preferences among preadolescent children. The International Journal of Eating Disorders, 10(2), 199e208. doi:10.1002/1098-108X(199103)10:2<199::AID-EAT2260100209>3.0.CO;2-D. Declaration of Helsinki e Ethical principles for medical research involving human subject. (January 2011). World Medical Association. Retrieved from http://www. wma.net/en/30publications/10policies/b3/17c.pdf. Deleel, M. L., Hughes, T. L., Miller, J. A., Hipwell, A., & Theodore, L. A. (2009). Prevalence of eating disturbance and body image dissatisfaction in young girls: an examination of the variance across racial and socioeconomic groups. Psychology in the Schools, 46(8), 767e775. doi:10.1002/pits.20415. Duncan, M. J., Al-Nakeeb, Y., Nevill, A. M., & Jones, M. V. (2006). Body dissatisfaction, body fat and physical activity in British children. International Journal of Pediatric Obesity, 1(2), 89e95. doi:10.1080/17477160600569420. Friedman, M. A., & Brownell, K. D. (1995). Psychological correlates of obesity: moving to the next research generation. Psychological Bulletin, 117(1), 3e20. doi:10.1037/0033-2909.117.1.3. Gibson, R. S. (2005). Principles of nutritional assessment (2nd ed.). New York: Oxford University Press. Gualdi-Russo, E., Albertini, A., Argnani, L., Celenza, F., Nicolucci, M., & Toselli, S. (2008). Weight status and body image perception in Italian children. Journal of Human Nutrition and Dietetics, 21(1), 39e45. doi:10.1111/j.1365-277X.2007. 00843.x.

Guedes, D. P., Lopes, C. C., Guedes, J. E. R. P., & Stanganell, L. C. (2006). Reproducibility and validity of the Baecke questionnaire for assessing of the habitual physical activity in adolescents. Revista Portuguesa de Ciências do Desporto, 6(3), 265e274, Retrieved from http://www.scielo.oces.mctes.pt/pdf/rpcd/v6n3/v6n3a02.pdf. Huang, J. S., Norman, G. J., Zabinski, M. F., Calfas, K., & Patrick, K. (2007). Body image and self-esteem among adolescents undergoing an intervention targeting dietary and physical activity behaviors. The Journal of Adolescent Health, 40(3), 245e251. doi:10.1016/j.jadohealth.2006.09.026. Jelliffe, D. B., & Jelliffe, E. F. P. (1989). Community nutritional assessment: With special reference to less technically developed countries. Oxford: Oxford University Press. Jensen, C. D., & Steele, R. G. (2009). Brief report: body dissatisfaction, weight criticism, and self-reported physical activity in preadolescent children. Journal of Pediatric Psychology, 34(8), 822e826. doi:10.1093/jpepsy/jsn131. Jones, R. L., Fries, E., & Danish, S. J. (2007). Gender and ethnic differences in body image and opposite sex figure preferences of rural adolescents. Body Image, 4(1), 103e108. doi:10.1016/j.bodyim.2006.11.005. Khor, G. L., Zalilah, M. S., & Phan, Y. Y. (2009). Perceptions of body image among Malaysian male and female adolescents. Singapore Medical Journal, 50(3), 303e311, Retrieved from http://smj.sma.org.sg. Kim, D. S., & Kim, H. S. (2009). Body-image dissatisfaction as a predictor of suicidal ideation among Korean boys and girls in different stages of adolescence: a twoyear longitudinal study. The Journal of Adolescent Health, 45, 47e54. doi:10.1016/ j.jadohealth.2008.11.017. Kircaldy, B. D., Shephard, R. J., & Siefen, R. G. (2002). The relationship between physical activity and self-image and problem behavior among adolescents. Social Psychiatry and Psychiatric Epidemiology, 37(11), 544e550. doi:10.1007/ s00127-002-0554-7. Knauss, C., Paxton, S. J., & Alsaker, F. D. (2007). Relationships amongst body dissatisfaction, internalization of the media body ideal and perceived pressure from media in adolescent girls and boys. Body Image, 4(4), 353e360. doi:10.1016/j.bodyim.2007.06.007. Liechty, J. M. (2010). Body image distortion and three types of weight loss behaviors among nonoverweight girls in the United States. The Journal of Adolescent Health, 47(2), 176e182. doi:10.1016/j.jadohealth.2010.01.004. McCabe, M. P., & Ricciardelli, L. A. (2004). A longitudinal study of pubertal timing and extreme body change behaviors among adolescent boys and girls. Adolescence, 39(153), 145e166, Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/ Abstract. McCabe, M. P., Ricciardelli, L., Waga, G., Goundar, R., & Fotu, K. (2009). Body image and body change strategies among adolescent males and females from Fiji, Tonga and Australia. Body Image, 6(4), 299e303. doi:10.1016/j.bodyim. 2009.06.001. McElhone, S., Kearney, J. M., Giachetti, I., Zunft, H. J., & Martínez, J. A. (1999). Body image perception in relation to recent weight changes and strategies for weight loss in a nationally representative sample in the European Union. Public Health Nutrition, 2(1), 143e151. doi:10.1017/S1368980099000191. Mciza, Z., Goedeck, J. H., Steyn, N. P., Charlton, K., Puoane, T., Meltzer, S., et al. (2005). Development and validation of instruments measuring body image and body weight dissatisfaction in South African mothers and their daughters. Public Health Nutrition, 8(5), 509e519. doi:10.1079/PHN2005814. Mellor, D., McCabe, M., Ricciardelli, L., Yeow, J., Daliza, N., & Hapidzal, N. F. (2007). Sociocultural influences on body dissatisfaction and body change behaviors among Malaysian adolescents. Body Image, 6(2), 121e128. doi:10.1016/ j.bodyim.2008.11.003. Moreno, J. A., Cervelló, E., & Moreno, R. (2008). Importancia de la práctica físicodeportiva y del género en el autoconcepto físico de los 9 a los 23 años. International Journal of Clinical and Health Psychology, 8(1), 171e183, Retrieved from http://www.psiquiatria.com/articulos/psicologia/psicologia_deportiva/41152/. Niskar, A., Baron-Epel, O., Garty-Sadalon, N., & Keinan-Boker, L. (2009). Body weight dissatisfaction among Israeli Jewish and Arabian women with normal or overweight-obese body mass index, Israeli INHIS-1, 2003e2004. Preventing Chronic Disease, 6(2), A51, Retrieved from www.cdc.gov/pcd/issues/2009/apr/ 08_0118.htm. Olvera, N., Suminski, R., & Power, T. G. (2005). Intergenerational perceptions of body image in Hispanics: role of BMI, gender, and acculturation. Obesity Research, 3(11), 1970e1979. doi:10.1038/oby.2005.242. Pan, S. Y., Cameron, C., DesMeules, M., Morrison, H., Craig, C. L., & Jiang, X. (2009). Individual, social, environmental, and physical environmental correlates with physical activity among Canadians: a cross-sectional study. BMC Public Health, 16, 9e21. doi:10.1186/1471-2458-9-21. Paxton, S. J., Eisenberg, M. E., & Neumark-Sztainer, D. (2006). Prospective predictors of body dissatisfaction in adolescent girls and boys: a five-year longitudinal study. Developmental Psychology, 42(5), 888e899. doi:10.1186/ 1471-2458-9-21. Pimenta, A., Sánchez-Villegas, A., Bes-Rastrollo, M., López, C. N., & MartínezGonzález, M. A. (2009). Relationship body image disturbance and incidence of depression: the SUN prospective Cohort. BMC Public Health, 9, 1. doi:10.1186/ 1471-2458-9-1. Ramos, E., Lopes, C., Oliveira, A., & Barros, H. (2009). Unawareness of weight and height e the effect on self-reported prevalence of overweight in a population e based study. The Journal of Nutrition, Health & Aging, 13(4), 310e314. doi:10.1007/s12603-009-0028-7. Schneider, N., Frieler, K., Pfeiffer, E., Lehmkuhl, U., & Salbach-Andrae, H. (2009). Comparison of body size estimation in adolescents with different types of eating disorders. European Eating Disorders Review, 17(6), 468e475. doi:10.1002/erv.956.

M.J. Monteiro Gaspar et al. / Psychology of Sport and Exercise 12 (2011) 563e569 Sepulveda, A. R., Carrobles, J. A., & Gandarillas, A. M. (2008). Gender, school and academic differences among Spanish university students at high-risk for developing and eating disorder: an epidemiological study. BMC Public Health, 8, 102. doi:10.1186/1471-2458-8-102. Sepulveda, A. R., Carrobles, J. A., Gandarillas, A. M., Poveda, J., & Pastor, V. (2007). Prevention program for disturbed eating and body dissatisfaction in a Spanish university population: a pilot study. Body Image, 4(3), 317e328. doi:10.1016/ j.bodyim.2007.05.001. Smith, B. L., Handley, P., & Eldredge, D. A. (1998). Sex differences in exercise motivation and body-image satisfaction among college students. Perceptual and Motor Skills, 86(2), 723e732. doi:10.2466/PMS.86.2.723-732. Sobral, F., & Vasconcelos, O. (1996). Perceived somatotype as indicator of accuracy of body image, a method using somatotype attitudinal distance. Perceptual and Motor Skills, 82, 1107e1110. Stice, E., Hayward, C., Cameron, R. P., Killen, J. D., & Taylor, C. B. (2000). Body image and eating disturbances predict onset of depression among female adolescents e a longitudinal study. Journal of Abnormal Psychology, 109(3), 438e444. doi:10.1037/0021-843X.109.3.438. Stockton, M., Lanctot, J. Q., McClanahan, B. S., Klesges, L. M., Klesges, R. C., Kumanyika, S., et al. (2009). Self-perception and body image associations with body mass index among 8e10-year-old African American Girls. Journal of Pediatric Psychology, 1e11. doi:10.1093/jpepsy/jsp023.

569

Strauss, R. S. (1999). Self-reported weight status and dieting in a cross-sectional sample of young adolescents: National Health and Nutrition Examination Survey III. Archives of Pediatrics and Adolescent Medicine, 153(7), 741e747, Retrieved from http://archpedi.ama-assn.org/cgi/content/abstract/153/7/741. Van den Berg, P. A., Mond, J., Eisenberg, M., Ackard, D., & Neumark-Sztainer, D. (2010). The link between body dissatisfaction and self-esteem in adolescents: similarities across gender, age, weight status, race/ethnicity, and socioeconomic status. The Journal of Adolescent Health, 47(3), 290e296. doi:10.1016/ j.jadohealth.2010.02.004. Wang, Y., Liang, H., & Chen, X. (2009). Measured body mass index, body weight perception, dissatisfaction and control practices in urban, low-income African American adolescents. BMC Public Health, 9, 183. doi:10.1186/1471-2458-9-183. Warburton, D. E. R., Nicole, C. W., & Bredin, S. S. D. (2006). Health benefits of physical activity: the evidence. Canadian Medical Association Journal, 174, 801e809. doi:10.1503/cmaj.051351. Young-Hyman, D., Schlundt, D. G., Herman-Wenderoth, L., & Bozylinski, K. (2003). Obesity, appearance, and psychosocial adaptation in young African American children. Journal of Pediatric Psychology, 28(7), 463e472. doi:10.1093/jpepsy/jsg037. Zaborskis, A., Petronyte, G., Sumskas, L., Kuzman, M., & Iannotti, R. J. (2008). Body image and control among adolescents in Lithuania, Croatia, and United States in the context of global obesity. Croatian Medical Journal, 49(2), 233e242. doi:10.3325/cmj.2008.2.2.