انگیزش ورزش مبتنی بر شکل ظاهری رابطه بین فرکانس ورزش و تصویر ذهنی مثبت از جسم را تعدیل می کند
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|30038||2014||8 صفحه PDF||سفارش دهید||6070 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Body Image, Volume 11, Issue 2, March 2014, Pages 101–108
Abstract Individuals with a positive body image appreciate their bodies, hold an internal perspective of their bodies, and are satisfied with the functionality of their bodies. Research shows that positive body image is more complex than the absence of body dissatisfaction. Although exercise reduces women's body dissatisfaction, very little research has explored how, or even whether, exercise is associated with positive body image. Therefore, we examined whether exercise frequency was positively related to three aspects of positive body image (body appreciation, internal body orientation, and functional body satisfaction) among 321 college women. Appearance-based exercise motivation (the extent exercise is pursued to influence weight or shape) was hypothesized to moderate these associations. Hierarchical moderated regression analyses showed that exercise frequency was related to higher positive body image, but high levels of appearance-based exercise motivation weakened these relationships. Thus, messages promoting exercise need to de-emphasize weight loss and appearance for positive body image.
Positive body image refers to attitudes and behaviors that reflect a healthy acceptance of and appreciation for the body that go beyond the absence of body dissatisfaction. This construct provides a broader perspective to the study of embodiment, which has traditionally focused on problematic behaviors and attitudes. Research that explores the correlates and characteristics of positive body image has important implications for prevention and treatment because it provides clients and practitioners with an understanding of what body-related attitudes and behaviors to strive toward, not just what to avoid. Reflecting on the importance of positive body image in their recent handbook, Smolak and Cash (2011, p. 472) declared that focusing on positive body image is “essential to the future of the field.” Although positive body image has appeared in the scholarly literature only within the past decade, research suggests that it is a multi-faceted construct consisting of body appreciation, an internal orientation toward the body, and satisfaction with the body's capabilities. Body appreciation refers to unconditional approval and respect for the body ( Avalos et al., 2005, Frisén and Holmqvist, 2010 and Wood-Barcalow et al., 2010). Individuals who appreciate their bodies recognize that their bodies are unique and they accept their flaws as well as their assets. They show respect for the body by attending to its needs, engaging in health-promoting behaviors, and cognitively rejecting cultural messages that promote unrealistic standards for thinness. Internal body orientation refers to a focus on what the body can do and how it feels as opposed to how it looks ( Frisén and Holmqvist, 2010 and Wood-Barcalow et al., 2010). Instead of habitually monitoring their outward appearance, individuals with an internal body orientation are concerned with comfort. Finally, functional body satisfaction refers to approval of and satisfaction with the body's physical capabilities ( Abbott and Barber, 2010, Frisén and Holmqvist, 2010 and Wood-Barcalow et al., 2010). Curiously, little research has explored the connection between positive body image and exercise, despite substantial evidence that physical activity reduces women's negative feelings about their bodies. A variety of methodologies have demonstrated this connection, including self-report correlational studies (Hausenblas & Fallon, 2002), ecological momentary assessment (Lepage & Crowther, 2010), quasi-experimental designs in which exercisers were compared with non-exercisers (Davis, 1990), and experimental designs (Vocks, Hochler, Rohrig, & Legenbaugher, 2009). Three major meta-analyses, including one that focused on pre/posttest experimental designs, have concluded that exercise is consistently associated with reduced body dissatisfaction (Campbell and Hausenblas, 2009, Hausenblas and Fallon, 2006 and Reel et al., 2007). In addition, a review of six exercise interventions directed toward eating disorder patients found generally positive effects, such as decreased drive for thinness and body dissatisfaction (Hausenblas, Cook, & Chittester, 2008). Given the consistent inverse relationship between exercise and body dissatisfaction, it is likely that exercise also improves the positive ways that women experience their bodies. However, reducing negative features (such as body dissatisfaction) is not the same as increasing positive features ( Fredrickson, 2001 and Tylka, 2011), and to date, no studies have empirically tested this potential benefit of exercise. Three qualitative studies provide indirect support. First, women who have a positive body image often mentioned regular exercise as a way to promote care of their bodies and overall well-being ( Wood-Barcalow et al., 2010). These women viewed exercise as a way to relieve stress, enjoy themselves, and improve their health rather than to lose weight. Second, the vast majority (i.e., 93%) of adolescents with a positive body image were exceptionally active, participating in various sports and other physical activity (e.g., dancing, jogging) and found exercise “joyful and health-promoting” and “natural part of life” ( Frisén & Holmqvist, 2010, p. 208). Only 20% of the adolescents mentioned that they exercised in order to take care of or change their appearance. Third, female collegiate athletes described feeling proud of their strong and developed bodies ( Krane, Choie, Baird, Aimar, & Kauer, 2004). They focused on the function of their well-developed muscles and appreciated how their strength helped them in their sport. They recognized that the female athletic body has distinctive desirable features, despite the ways that it diverges from the cultural ideal of femininity. Many of the feelings and attitudes described by these athletes are similar to the characteristics of positive body image, suggesting a connection between physical activity and positive body image. Two quantitative studies also have provided support for a connection between exercise and positive body image: modern dancers and street dancers demonstrated higher body appreciation relative to non-dancers and college women ( Langdon and Petracca, 2010 and Swami and Tovée, 2009). It is likely that the psychological benefits of exercise are not the same for all women. Various characteristics of the exerciser have been shown to moderate the psychological outcomes associated with exercise, including pre-existing body image disturbance, enjoyment of the activity, and cognitions during the activity (Blanchard et al., 2004, Lepage and Crowther, 2010, Raedeke, 2007 and Vocks et al., 2009). For example, women randomly assigned to a bout of physical activity reported feeling slimmer following the exercise session, and the effect was stronger for women with greater pre-experimental desire for thinness and weight concerns (Vocks et al., 2009). Among college students and corporate fitness participants, an acute exercise bout was generally associated with enhanced positive and reduced negative affect (Raedeke, 2007). However, participants who enjoyed the exercise experienced the greatest gains in positive affect. An experimental study randomly assigned participants to a bout of running or a no-exercise control group (Blanchard et al., 2004). Those in the exercise condition experienced increases in positive affect (such as revitalization and positive engagement) relative to the control participants. The participants’ cognitions moderated the effects; when participants focused on the exercise (such as their breathing) they experienced reduced gains in positive affect relative to those who allowed their minds to wander during the running session. Results such as these indicate that multiple characteristics of the participant can influence the psychological effects of exercise. A potentially key moderator is the individual's motivation for exercising. Previous research has shown that women who exercise primarily for appearance reasons are likely to experience elevated rates of eating disorder symptoms (including negative feelings about the body), elevated depressive symptoms, and lower self-esteem (DiBartolo et al., 2007, Goncalves and Rui Gomes, 2012 and Mond et al., 2006). In contrast, among women who engaged in physical activity for health and enjoyment reasons, there was a negative correlation between exercise and eating disorder symptoms, including body dissatisfaction (DiBartolo et al., 2007). Even the physical health effects of exercise appear to depend upon exercise motivation; exercise motivated by health and enjoyment was correlated with lower pulse, systolic blood pressure, and salivary stress hormone levels while exercise motivated by weight was unrelated to these physical measures (DiBartolo et al., 2007). Together, these findings imply that exercise for weight or shape reasons is qualitatively distinct from exercise that is not motivated by appearance. Thus, it is likely that whether the relationship between exercise and body image is adaptive depends upon the extent to which the physical activity is intended to influence weight or shape. However, this idea has not yet been explored in regard to positive body image. Such investigations would be worthwhile because (a) empirical research has shown that positive body image is a more comprehensive construct than low levels of body dissatisfaction (Avalos et al., 2005); (b) quantitative research has not explored the relationship between exercise and positive body image beyond dance despite qualitative research supporting this connection (Frisén & Holmqvist, 2010); and (c) knowing whether appearance-based motivation for exercise assuages the potential beneficial qualities of exercise on body appreciation, internal body orientation, and functional body satisfaction has important clinical implications for the promotion and maintenance of positive body image and healthy exercise. Therefore, the purpose of the present study was to examine the relationships between exercise frequency and three aspects of positive body image: body appreciation, internal body orientation, and functional body satisfaction. We hypothesized that exercise frequency would show a positive relationship with each positive body image criterion, but that the strength of this relationship would depend upon the extent to which exercise is motivated by weight or shape reasons. We operationalized exercise as exercise frequency because it has been shown that frequency, not duration, is the major factor related to body concerns (Reel et al., 2007). We explored these connections with an undergraduate sample because colleges usually provide opportunities for regular physical activity for their students (e.g., gymnasiums, sports clubs or teams). These opportunities are generally available without an additional expense as the use of facilities is typically embedded in tuition.
نتیجه گیری انگلیسی
Preliminary Analyses Prior to the analysis of the hypotheses, data were examined for missing values and outliers (both univariate and multivariate). Of the initial 325 participants who were included in the data set, only 301 completed the first section of the Godin (all 325 participants completed the items for the 3-item exercise composite measure, including the “sweat” item on the second part of the Godin). For other measures, a total of eight (0.03%) participants had at least one missing data point, and the count for item-level missingness ranged from 0 to 1.5% (M = 0.16%), which is considered extremely low ( Parent, 2013). Therefore, mean substitution was used to replace missing values for the non-exercise measures. For all measures, item-level data points were missing completely at random according to Little's analysis, χ2(276, N = 321) = 279.65, p = .427. An outlier analysis detected seven univariate outliers, all from the Godin exercise frequency component. All seven univariate outliers were extreme (i.e., ranging from 5 SD to 49 SD above average), with each surpassing the criterion for detection and removal (zs > 3.29, ps < .001; Tabachnick & Fidell, 2013). For these participants, we deleted their Godin exercise frequency score but retained their responses to other variables. Analyses for multivariate outliers revealed four cases with extremely large Mahalanobis distance values (i.e., values at or above 20) across all regression analyses performed. These four cases were deleted, leaving 321 participants in the final data set. While we had 290 participants with Godin exercise frequency scores, we had the 3-item composite exercise score for all 321 participants. Descriptive statistics and intercorrelations for the major study variables are presented in Table 1. Skew and kurtosis values were well below established values that pose problems in regression analyses (i.e., skew > 3.00 and kurtosis > 10.00; Kline, 2010): skew ranged from −0.61 to 0.39 and kurtosis ranged from −1.05 to 0.21. Thus, no variable was transformed. Table 1. Variable means, standard deviations, and intercorrelations. Variable M SD 1 2 3 4a 5 1. Body Appreciation 3.56 0.73 2. Internal Body Orientation 3.39 1.10 .55*** 3. Functional Body Satisfaction 3.46 0.94 .52*** .39*** 4. Godin Strenuous & Moderate Exercisea 36.38 21.62 .10 .16** .36*** 5. Exercise Composite Measure 2.42 0.78 .12* .08 .41*** .73*** 6. Appearance-based Exercise Motivation 3.37 1.04 −.07 −.19** .12* .38*** .47*** Note. N = 321. a n = 290. * p < .05. ** p < .01. *** p < .001. Table options We evaluated the psychometric properties of the 3-item exercise composite before examining it as a measure of exercise in the main analyses. Item-total correlations ranged from .75 to .85 (α = .86). The Kaiser–Meyer–Olkin measure of sampling adequacy indicated that the three items had adequate common variance (.714), and Bartlett's Test of Sphericity revealed that the correlation matrix was factorable, χ2(3) = 460.41, p < .001. Principal axis factoring with parallel analysis demonstrated that the items loaded on one factor and accounted for 78.54% of this factor's variance (eigenvalue = 2.36). Item-factor loadings ranged from .73 to .91, and communalities ranged from .47 to .64. As indicated in Table 1, the 3-item composite was correlated r = .73 with the Godin exercise frequency score, upholding its convergent validity. Hierarchical Moderated Regression Analyses In order to test the hypothesis that appearance-based exercise motivation would moderate the link between exercise frequency and positive body image, three separate hierarchical regression analyses were performed (i.e., one analysis for each measure of positive body image). Because the Godin Leisure-Time Exercise Questionnaire is established as a psychometrically sound measure of exercise frequency, we used it as the primary measure to estimate exercise frequency in the analyses. However, because we only had responses on the Godin from a subset of the total sample (n = 290), we also ran the analyses using the 3-item exercise composite to determine whether findings were upheld for the full sample (N = 321). For each regression, exercise frequency and appearance-based exercise motivation were centered, and an interaction term was created by multiplying the centered values. In Step 1, exercise frequency and appearance-based exercise motivation were entered. In Step 2, the interaction term was entered. To control for Type I error, the Bonferroni adjustment was applied (i.e., p = .05/3 = .017). For each regression, a simple slopes analysis ( Aiken & West, 1991) was conducted and a graph generated to compare the relationships between exercise frequency and the criterion at low (−1 SD), average (mean), and high (1 SD) levels of the moderator. In the first analysis (see Table 2), body appreciation was the criterion variable. At Step 1, Godin exercise frequency and appearance-based exercise motivation were both associated with body appreciation in a positive and negative direction, respectively. Consistent with our hypothesis, there was a significant interaction at Step 2, indicating that the positive contribution of exercise frequency to body appreciation was weakened by the extent to which exercise was pursued for appearance reasons. The graph of the interaction is illustrated in Fig. 1, and the simple slopes analyses are included in Table 3. When women had low to average levels of appearance-based exercise motivation, exercise frequency was positively related to body appreciation. But when appearance-based exercise motivation was high, this relationship was not significant. Table 2. Hierarchical multiple regression analyses predicting positive body image. Step/variable Regression Analyses Using the Godin Exercise Frequency Scorea Regression Analyses Using the 3-Item Composite Exercise Scoreb R2 ΔR2 β t p R2 ΔR2 β t p Body AppreciationF(3, 286) = 9.998,p < .001 Body AppreciationF(3, 317) = 10.144,p < .001 Step 1 .041 .035 Exercise Frequency .172 2.76 .006 .196 3.14 .002 Appearance Motivation −.192 −3.07 .002 −.163 −2.61 .009 Step 2 .095 .054 .088 .053 Exercise × Appearance Motivation −.241 −4.11 <.001 −.242 −4.28 <.001 Internal Body OrientationF(3, 286) = 14.797,p < .001 Internal Body OrientationF(3, 317) = 12.600,p < .001 Step 1 .109 .071 Exercise Frequency .276 4.58 <.001 .213 3.47 .001 Appearance Motivation −.314 −5.21 <.001 −.290 −4.72 <.001 Step 2 .135 .025 .107 .036 Exercise × Appearance Motivation −.166 −2.89 .004 −.199 −3.55 <.001 Functional Body SatisfactionF(3, 286) = 16.535,p < .001 Functional Body SatisfactionF(3, 317) = 25.018,p < .001 Step 1 .129 .174 Exercise Frequency .369 6.19 <.001 .454 7.85 <.001 Appearance Motivation −.028 −0.48 .635 −.097 −1.69 .093 Step 2 .148 .019 .192 .018 Exercise × Appearance Motivation −.142 −2.51 .013 −.141 −2.65 .008 a n = 290. b n = 321. Table options Full-size image (15 K) Fig. 1. Regression lines showing the relationship between exercise frequency and body appreciation by appearance-based exercise motivation. The estimates for exercise were based on Godin Strenuous × moderate exercise frequency scores. Figure options Table 3. Simple slopes analyses. Simple Slopes Using the Godin Exercise Frequency Scorea Simple Slopes Using the 3-Item Composite Exercise Scoreb β t p β t p Body Appreciation Body Appreciation 1 SD below mean on appearance motivation .428 4.92 <.001 .442 5.38 <.001 mean .171 2.81 .005 .187 3.06 .002 1 SD above mean on appearance motivation −.086 −0.99 .325 −.068 −0.81 .420 Internal Body Orientation Internal Body Orientation 1 SD below mean on appearance motivation .452 5.31 <.001 .411 5.01 <.001 mean .275 4.63 <.001 .206 3.37 .001 1 SD above mean on appearance motivation .098 1.15 .252 .002 0.02 .983 Functional Body Satisfaction Functional Body Satisfaction 1 SD below mean on appearance motivation .521 6.16 <.001 .602 7.77 <.001 mean .368 6.24 <.001 .448 7.77 <.001 1 SD above mean on appearance motivation .216 2.54 .012 .294 3.74 <.001 a n = 290. b n = 321. Table options Similar results were obtained for internal body orientation (see Table 2). In Step 1, Godin exercise frequency and appearance-based exercise motivation were significantly associated with internal body orientation in a positive and negative direction, respectively. As predicted, the interaction of exercise frequency and appearance-based exercise motivation was significant at Step 2, suggesting that the positive contribution of exercise to internal body orientation was weakened by the extent to which exercise was pursued for appearance reasons. Fig. 2 presents these regression lines. Among women with low to average levels of appearance-based exercise motivation, exercise frequency was associated with higher rates of internal body orientation (Table 3). However, among those who exercised primarily for appearance-based reasons, exercise frequency was not associated with internal body orientation. Full-size image (16 K) Fig. 2. Regression lines showing the relationship between exercise frequency and internal body orientation by appearance-based exercise motivation. The estimates for exercise were based on Godin Strenuous × moderate exercise frequency scores. Figure options In the third regression analysis, functional body satisfaction was the criterion variable. At Step 1, Godin exercise frequency, but not appearance-based exercise motivation, was associated with functional body satisfaction (Table 2). As hypothesized, there was a significant interaction between these two predictors, which is illustrated in Fig. 3. Again, exercise frequency was positively associated with satisfaction with what one's body can do, but this relationship was weaker for women who exercised primarily for appearance-based reasons (Table 3). Full-size image (13 K) Fig. 3. Regression lines showing the relationship between exercise frequency and functional body satisfaction by appearance-based exercise motivation. The estimates for exercise were based on Godin Strenuous × moderate exercise frequency scores. Figure options These regressions were repeated using the exercise composite score in lieu of the Godin exercise frequency score to ensure that findings were similar within the full data set. Thus, the 3-item exercise composite score and appearance-based motivation were entered in Step 1, and the interaction between the exercise composite exercise score and appearance-based motivation was entered in Step 2, in the prediction of body appreciation, internal body orientation, and functional body satisfaction. As can be seen in Table 2 and Table 3, identical trends were found with the exercise composite score and the Godin exercise frequency score, ensuring that appearance-related motivation weakened the relationship between exercise and positive body image with the full sample. Given this consistency, we do not provide graphs for the results using the composite exercise measure; however, these graphs can be obtained from the corresponding author.