As a result of the value placed on health, fitness, and appearance, many individuals in today's Western world strive to attain the “ideal physique.” One way in which to attain this physique is through exercise. Despite research that has demonstrated a sustained and adequate exercise program plays an important role in weight loss and healthy weight maintenance (2), not all individuals who exercise experience positive outcomes. In fact, some take their exercising to pathological levels, consequently sacrificing their physical and mental health. One group of individuals that may take their exercise behaviors to extreme levels are those with muscle dysmorphia (MD) (28).
MD is described in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition as an obsession with muscularity and leanness (1). This obsession results in a fear that one is too small, and may lead to such behaviors as compulsive weightlifting (28) and dietary restraint (12). Although there are several behaviors associated with MD, the most common is weight training, as it is a means to gain muscle mass. Those with MD are often recognized as dedicated weight trainers due to the frequency and duration with which they lift weights (26). In fact, there are anecdotal reports that some individuals with MD work out 5-6 hours per day and spend another 6 hours per day thinking about strategies to gain muscle mass (29). Those participating in such high amounts of weight training can experience serious physical injury (28), as well as social detriments such as alienating friends and loved ones (29). Initially, MD was believed to exist almost exclusively in men (28); therefore, much of the research conducted on MD has focused on men (e.g., 16,26). However, women are becoming more interested in weight training, with gym memberships for women almost doubling between 1990 (20.7 million) and 2003 (39.4 million) (33) and a 134% increase in women lifting free weights (32). Further to increased numbers of women participating in weight training, MD has been described in women (10) and there is a need for more research assessing both genders.
In addition to weight training behaviors, diet is often utilized to attain lean muscle mass (e.g., 14,16). While individuals with anorexia nervosa have a primary preoccupation with eating and a secondary preoccupation with exercise, individuals with MD experience the opposite pattern (4). Despite dietary concerns being secondary in MD, dietary habits are often controlled to extreme limits where food can only be prepared at home so as to control for intake of specific percentages of fat, protein, and carbohydrates (28). It is important to note that those individuals trying to gain weight are typically trying to gain muscle mass (18,24). Women also participate in dietary strategies, such as the high-protein diet (9,10).
For many, the reason for weight training is the drive for muscularity. Furthermore, those who score higher on a measure of MD displayed a higher degree of the drive for muscularity (15). The drive for muscularity is a term coined by McCreary and Sasse (21) that describes an individual's motivation to become more muscular. It has been suggested that some of the attitudinal and behavioral outcomes associated with MD are consistent with the drive for muscularity (e.g., 15,21,23). For example, it was found that men who were easily made anxious, had strong tendencies for perfectionism, and were highly focused on physical appearance and fitness were highest in the drive for muscularity (4), and these correlates were also identified in those with MD (26). Additionally, just as the drive for thinness is considered a precursor or risk factor for the development of anorexia nervosa (7) the drive for muscularity has been identified as a precursor for the development of MD (26). However, it is unclear whether a certain level of the drive for muscularity is indicative of MD; thus, further research into this matter has been recommended (25).
McCreary and Sasse (21) developed the 15-item Drive for Muscularity Scale (DMS), which assesses the attitudinal and behavioral aspects of striving for muscularity. McCreary and Sasse found that both men and women demonstrate the drive for muscularity; however, it is more salient in men. The original conceptualization of the DMS (21) demonstrated adequate internal consistencies for the total score (boys, α = 0.84; girls, α = 0.78). An exploratory factor analysis showed a two-factor structure (body image and behavior) of the DMS was supported for men (22), but not for women. In order to allow for gender comparisons with the DMS, Gammage, Munroe-Chandler, and Hall (8) made several changes to the scale including changes to the wording to become more gender neutral, and the addition of a dietary subscale, which resulted in the establishment of a three-factor structure that applies to both genders: diet, attitude, and training behavior. The diet subscale was an important addition to the DMS due to the recent increase in popularity in high-protein diets for the purpose of weight loss and gaining muscle mass (20). The modified version of the DMS contains 17 items and shows adequate internal consistencies for all three subscales for men (Cronbach's alphas ranging from 0.79-0.87) and women (0.69-0.83). Therefore, the modified DMS may be a useful instrument for studying the drive for muscularity in a mixed gender sample.
Given that the modified DMS assesses diet, training behaviors, and the attitudinal aspect of the drive for muscularity, it is important to determine how these subscales relate to MD characteristics in men and women. Although the current sociocultural body ideal for women is lean, thin, and toned (11), alternate ideal body types exist beyond the ultra-thin ideal for women, that include some musculature. As mentioned previously, women also participate in dietary strategies such as the high-protein diet (10) in order to achieve the ideal toned, lean physique. McCreary (19) suggested that further research into the antecedents and consequences of the drive for muscularity was necessary. Moreover, although the relationship between MD and the drive for muscularity is an important area of research, only one study has examined it. It was found that male weight trainers with a high degree of preoccupation with muscle size, which was socially disruptive, also scored high on the DMS (15). The current study extends this research by including female weight trainers. Additionally, several studies linking various cognitions, behaviors, and personality traits to MD have been conducted (e.g., 13,26), yet no study has examined the predictive relationship between the drive for muscularity and MD symptoms in a mixed gender sample, despite suggestions from previous researchers (27). Therefore, the purpose of the current study was to examine the extent to which the three subscales of the modified DMS, (training, attitude, and diet) predicted MD characteristics in a recreational weight training sample, and whether there were significant differences in those associations between men and women.
Experimental Approach to the Problem
In this study, recreational weight trainers completed a self-report questionnaire in order to describe the relationship between the drive for muscularity and MD. It was hypothesized that the mean scores on the modified DMS subscales and the measure of MD would be higher for men than women since the ideal body type for men is a more muscular physique and women's fitness drives are related to achieving a lean, toned appearance. Additionally, it was hypothesized that the 3 subscales of the modified DMS would predict MD symptoms, and that a greater percentage of the variance would be accounted for in men when compared to women. By collecting data on weight training habits, and DMS and MD constructs in both men and women, gender comparisons were examined. Furthermore, due to the pervasiveness of striving for an “ideal physique” and the suggestion that the DMS can serve as a precursor for MD, it is important to study MD characteristics in a recreational weight training population in order to generalize results beyond the competitive weightlifters that have been most often studied.
Ethical clearance from the university's research ethics board was obtained and all participants signed informed consent documents. The participants included 114 male (n = 55) and female (n = 59) recreational weight trainers (i.e., those who do not lift weights for the purpose of competing in bodybuilding competitions). Participant were included if they indicated they performed at least 1 day of weight training each week. This 1 day of weight training could have been individual- or class-based; thus, weight-training experience and the frequency and amount of time spent weight training varied. The participants ranged in age from 18 to 64 years (Mage = 24.06, SD = 7.96). All participants were members of the university fitness center, and approximately 75% of the sample was comprised of kinesiology students.
The physical activities other than weight training in which the participants engaged were recorded in an open-ended format. The most common type of physical activity for men was cardiovascular training (58%), with traditionally masculine sports including hockey, basketball, soccer, and football being the second most common activity (25%). For women, cardiovascular training (e.g., running on the treadmill) was also the most common type of physical activity (71%), with very few women participating in the traditionally masculine sports (7%).
Table 1 shows the means and standard deviations for all demographic variables and describes the participants' training background and status. With respect to gender differences and the demographic variables, one-way analysis of variance (ANOVA) indicated the male weight trainers were significantly heavier (F(1,107) = 90.04, p < 0.01) and taller (F(1,107) = 94.55, p < 0.01) than the females weight trainers. Additionally, in terms of body size, the men had a significantly higher BMI (F(1,107) = 28.13, p < 0.01). The men and women reported weight training for 7-12 months on average. There were gender differences in activity levels, with men participating in significantly more days per week weight training than women (F(1,107) = 8.61, p < 0.01). Also, the men participated in more hours of weight training per week than women (F(1,107) = 20.40, p < 0.01). Conversely, women participated in physical activities other than weight training more hours per week (F(1,07) = 6.16, p < 0.01) than men. Overall, it is clear that this sample was very active in both recreational weight training and other physical activities.
All participants were recruited through the university fitness center or undergraduate kinesiology courses. All data were collected between October and March; thus, assessment occurred over a range of seasons. As fitness center members were leaving, they were approached and asked to participate in the study, or if in undergraduate kinesiology courses, asked to fill out the questionnaire if they met eligibility requirements at the end of class. Researchers distributed informed consent forms, letters of information, and questionnaires directly to participants, who returned them immediately to the researchers upon completion. The questionnaires took approximately 10 minutes to complete.
Participants completed demographic information including their gender, age, weight, height, the number of years weight training, weight training frequency, number of hours spent weight training, and type and frequency of other physical activity.
The Muscle Appearance Satisfaction Scale (MASS) (17) is a newly developed measurement scale that assesses characteristics of MD. The 19-item self-report measure was developed based on the criteria for MD. All ratings are on a 7-point Likert scale, with 1 being definitely disagree and 7 being definitely agree. Cafri and colleagues (3) suggested that the MASS meets the guidelines for assessing body image focusing on muscularity by testing attitudes and relevant behaviors. During the development of this measure, Mayville and colleagues established internal consistency, test-retest reliability, and construct validity. There was support for 5 subscales (bodybuilding dependence, checking, substance use, injury, satisfaction), as well as the total score displaying adequate internal consistency. Further support for the use of the total score as a measure of MD has been provided, with the total score correlated to measures of body dysmorphic disorder, bodybuilding dependency, and social physique anxiety, thus displaying convergent validity (17). Due to the support for the MASS by experts in the field, the reliability and validity of the measure, and that it taps into 5 central components of MD, it seemed the most fitting choice. For the purpose of this study, the total score of the MASS was employed (male α = 0.89; female α = 0.82).
The drive for muscularity was assessed using the modified DMS (8), which is a 17-item self-report measure of the extent to which people desire to have a more muscular physique. Items are marked on a 6-point Likert scale ranging from 1 (never) to 6 (always). As described above, the modified DMS was found to have a 3-factor structure: attitude, training behavior, and diet, which are applicable with both men and women (8), and remains the only valid instrument measuring both men and women's drive for muscularity. As such, the DMS was chosen as the preferred measure for the drive for muscularity. The internal consistencies in the current study for the attitude subscale (male α = 0.88; female α = 0.86) and the dietary subscale (male α = 0.89; female α = 0.84) were higher than the training subscale (male α = 0.66; female α = 0.59) (see Table 2).
Prior to any analyses, scores on the MASS and the modified DMS were examined for outliers. No unacceptable values were found. A series of ANOVAs were conducted in order to examine possible gender differences with respect to the scores on the subscales of the modified DMS and MASS. In previous validation studies the use of item to scale correlations is employed to determine the consistency of relationships across items (6). A moderate correlation (e.g., >0.3 and <0.8) indicates reliability (6). In order to determine the relationship between the modified DMS subscale scores and the MASS scores, a linear regression analysis was undertaken with the level of significance p < 0.05. A linear regression was selected since the current study assessed recreational weight training with the hypothesis that the drive for muscularity (modified DMS) will be predictive of MD characteristics (MASS). A separate regression analysis was conducted for each gender (21) as differences exist between genders with respect to the drive for muscularity and MD. The amount of variance accounted for by the 3 subscales of the modified DMS in the MASS scores for each gender was compared to describe the pattern of the relationships between the 2 constructs for each gender.
The ANOVAs indicated that the male weight trainers scored significantly higher on the diet (F (1,110) = 26.98, p < 0.001) and the attitudinal (F (1,110) = 4.89, p < 0.05) subscales when compared to the female weight trainers. The training behavior subscale was not significantly different between men and women. Finally, an ANOVA indicated that there was a significant difference between the genders on the MASS scores (F(1,105) = 8.32, p < 0.05). See Table 2 for all means and standard deviations for the questionnaire scores.
The linear regression analyses revealed that the 3 subscales of the modified DMS significantly predicted MD characteristics in male and female weight trainers accounting for 69% (F(3,43) = 31.59, p < 0.05) and 46% (F(3,53) = 14.82, p < 0.05) of the total variance respectively (see Table 3). For the men, the results revealed that training behavior accounted for the most variance in MASS scores for the men. Training behavior accounted for 32% of the variance in MASS scores over and above that explained by the other DMS subscales for the men. Dietary habits accounted for 29%, while the attitudinal subscale accounted for 15% of the variance in MASS scores each independently for male weight trainers. For the women, the largest percentage of the variance in MASS scores was accounted for by the dietary subscale (33%). Training behavior and attitude subscales accounted for much less of the variance at 17% and 16%, respectively (Table 3).
The current study examined the drive for muscularity in male and female recreational weight trainers and its prediction of MD characteristics. The scores on the DMS are consistent with previous studies assessing recreational weight training populations (e.g., 8). Although there is no clear cutoff point for score on the MASS to suggest clinical MD, mean scores in the current study (men = 2.24; women = 2.04) on a 7-point scale suggest the population assessed did not have strong tendencies for MD.
It was hypothesized that men would score higher on the 3 subscales of the modified DMS and the MASS than women. This hypothesis was partially supported as men reported significantly higher scores than women on the MASS as well as the attitudinal and diet subscales of the modified DMS, while the training subscale was not significantly different between genders. Previous literature using the 15-item DMS with a single higher order factor has found men to score higher on the DMS than women (22). However, in the current study using the 3-factor structure suggested by Gammage et al. (8), it was revealed that the training behavior subscale was not significantly different between the genders. The items that contribute to the training behavior subscale were intended to be gender neutral so that both men and women could be assessed for behavioral components of the drive. Differences between genders in the McCreary et al. (22) study were evident, perhaps because the population assessed consisted of general students, while the current study examined recreational weight trainers. Perhaps gender differences in the training behavior component of the drive are diminished when a weight training population is assessed. Due to the high level of physical activity in the sample, the behaviors involved in weight training such as changing one's schedule around their training regimen may have been necessary to attain their goals. In a recent study, it was found that recreational weight trained women self-selected intensities of around 50% of their 1RM, which is much lower than is recommended for increasing muscular strength and hypertrophy (30). Therefore, although their goals may differ with respect to the ideal body they are trying to attain (i.e., lean and toned for women, and big and muscular for men), both physiques can be attained through weight training. By changing the repetitions and the amount of weight lifted, both hypermuscular and lean/toned physiques can be attained. Therefore it is not surprising that the active population in the current study scored similarly across genders in the training subscale of the modified DMS.
Building from previous research that established higher levels of the drive for muscularity in those individuals who display higher tendencies towards MD in a weight training and fitness population (15), it was revealed that scores on the modified DMS did predict MD characteristics in a weight training sample. The findings from the regression analysis supported the main hypothesis that all 3 subscales of the modified DMS would predict MASS scores in male and female weight trainers. Finally, the hypothesis that the modified DMS subscales would account for a greater percentage of the variance in the men was supported. The relative importance of the subscales in the regression equations revealed that for men, both training and dietary habits accounted for a large portion of the variance in MASS scores. As for the female weight trainers, the dietary subscale accounted for much more of the variance compared to the other two subscales. This finding provides further support for the use of the 3-factor structure of the modified DMS that includes dietary habits as a separate subscale (8). Diet is an important factor in the drive for muscularity because the goal of gaining lean muscle mass is achieved through not only training, but also through maintaining a diet high in lean protein and taking supplements.
The finding of the dietary subscale accounting for a larger portion of the variance in the female participants suggests that although many women participate in weight training, those individuals who display more MD symptomology are more likely to engage in dietary strategies to enhance muscularity. This contradicts previous literature that indicated that men were more likely than women to engage in dietary habits (i.e., consuming large amounts of protein) with the goal of gaining muscularity (5). Perhaps a certain proportion of women who want to attain a muscular ideal believe in altering their dietary habits to achieve their goals with respect to muscularity, and consequently possess more MD characteristics. Altering one's diet and taking supplements has been a common strategy among men trying to build muscle and bulk (e.g., 24,31); however, now this trend is being seen in women (9,10).
Future directions with this area of research include assessing further variables that have been found to be associated with MD characteristics in men, such as depression (e.g., 27) in a weight-training sample that includes women. Additionally, differentiation between bodybuilders and recreational weight trainers may be necessary to draw conclusions with respect to differences in body image, training behaviors, dietary habits, and MD in men versus women. Perhaps female bodybuilders are not similar in various correlates to either male bodybuilders or weight trainers of either gender due to different body type ideals and social standards. Additionally, more testing of the MASS and the modified DMS is necessary. In particular, this was the first time that the MASS was used in a sample including women, and further validation of the 3 subscales of the modified DMS is required for both genders.
The main limitation of the current study was the homogeneous sample used. The participants, given their education in health and fitness and their high levels of activity, may have answered the questionnaires with a degree of social desirability. Although dissatisfaction with muscularity (modified DMS attitude) showed predictive ability for MD in this population, future research should assess this relationship in a sample with clinically diagnosed MD. Furthermore, a broader scope of participants from different backgrounds and levels of education and fitness may provide more generalizable results. Additionally, the internal consistency of the training subscale of the modified DMS was slightly low. Perhaps this lower alpha was found because weight-training behaviors are complex and difficult to capture in a 3-item subscale. One possible effect resulting from this low Chronbach's alpha is lowered power of the training subscale in predicting MASS scores for the women.
Despite these limitations, the present study has contributed to the overall knowledge of MD. Support for the use of the subscales of the modified DMS to predict MD in an active population was found. However, further studies are necessary as both the three factor modified DMS and the MASS are newly developed tools. Future research should include further validation of these scales in various active and nonactive populations. The nonactive population might shed some light onto other aspects of MD and the drive for muscularity. Nonactive populations might hold similar attitudes towards muscularity (e.g., wanting to be larger), yet these individuals may not be motivated enough to participate in training behaviors. Perhaps muscularity is a concern for nonactive populations, but other values and activities are more important to them. Additionally, those individuals who only participate in weight training and no other physical activity may be more likely to possess a higher drive for muscularity and possess more symptoms of MD. Future research in this area should include prospective studies as cross-sectional data cannot indicate causation. Finally, future research should include clinical research as nonclinical populations are not a true indication of a psychiatric disorder such as MD. As mentioned previously, many of the measures used to assess both muscularity attitudes and MD have yet to be confirmed in a clinical population. Once there is a clearer understanding of how the drive for muscularity reliably predicts MD, screening, prevention, and educational programs can be established for MD and associated maladaptive behaviors.
The practical implications from this study include the generation of novel findings with respect to correlates of MD characteristics, as this is a newer construct that has not undergone much empirical research. This study revealed that the drive for muscularity is related to MD characteristics in a recreational weight training population. Additionally, there is an emerging ideal body type for women that includes more musculature and tone; therefore, it is essential to conduct more studies relating the maladaptive behaviors and attitudes involved in the pursuit of muscularity for women and men. Finally, the differential relationship between men and women found for dietary behaviors, training behaviors, and attitudes towards muscularity with MD characteristics provides a better understanding of MD and the pursuit of muscularity. Health and fitness professionals can use this information to screen for potential developments of MD in both men and women. However, further investigation of these constructs in a mixed gender sample is necessary before any concrete applications of these findings can be made.
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