Did you skip leg day? The neural mechanisms of muscle perception for body parts

While the neural mechanisms underpinning the perception of muscularity are poorly understood, recent progress has been made using the psychophysical technique of visual adaptation. Prolonged visual exposure to high (low) muscularity bodies causes subsequently viewed bodies to appear less (more) muscular, revealing a recalibration of the neural populations encoding muscularity. Here, we use visual adaptation to further elucidate the tuning properties of the neural processes underpinning muscle perception for the upper and lower halves of the body. Participants manipulated the apparent muscularity of upper and lower bodies until they appeared 'normal', prior to and following exposure to a series of top/bottom halves of bodies that were either high or low in muscularity. In Experiment 1, participants were adapted to isolated own-gender body halves from one of four conditions; increased (muscularity) upper (body half), increased lower, decreased upper, or decreased lower. Despite the presence of muscle aftereffects when the body halves the participants viewed and manipulated were congruent, there was only weak evidence of muscle aftereffect transfer between the upper and lower halves of the body. Aftereffects were significantly weaker when body halves were incongruent, implying minimal overlap in the neural mechanisms encoding muscularity for body half. Experiment 2 examined the generalisability of Experiment 1's findings in a more ecologically valid context using whole-body stimuli, producing a similar pattern of results as Experiment 1, but with no evidence of cross-adaptation. Taken together, the findings are most consistent with muscle-encoding neural populations that are body-half selective. As visual adaptation has been implicated in cases of body size and shape misperception, the present study furthers our current understanding of how these perceptual inaccuracies, particularly those involving muscularity, are developed, maintained, and may potentially be treated.

Small non-coding RNA profiling in patients with gastrointestinal cancer

BACKGROUND

Small non-coding (snc)RNAs, including microRNAs and P-element induced wimpy testis (PIWI)-interacting-RNAs (piRNAs), crucially regulate gene expression in both physiological and pathological conditions. In particular, some muscle-specific microRNAs (myomiRs) have been involved in the pathogenesis of cancer-induced muscle wasting. The aims of the present study were (i) to profile sncRNAs in both skeletal muscle and plasma of gastrointestinal cancer patients and (ii) to investigate the association among differentially expressed sncRNAs and the level of muscularity at body composition analysis.

METHODS

Surgical patients with gastrointestinal cancer or benign disease were recruited. Blood samples and muscle biopsies (rectus abdominis) were collected during surgery. Low muscularity patients were those at the lowest tertile of skeletal muscle index (SMI; CT-scan), whereas moderate/high muscularity patients were in the middle and highest SMI tertiles. SncRNAs in the muscle were assessed by RNAseq, circulating microRNAs were evaluated by qPCR.

RESULTS

Cancer patients (n = 25; 13 females, 52%) showed a mean age of 71.6 ± 11.2 years, a median body weight loss of 4.2% and a mean BMI of 27.0 ± 3.2 kg/m2 . Control group (n = 15; 9 females, 60%) showed a mean age 58.1 ± 13.9 years and a mean BMI of 28.0 ± 4.3 kg/m2 . In cancer patients, the median L3-SMI (cm2 /m2 ) was 42.52 (34.42; 49.07). Males showed a median L3-SMI of 46.08 (41.17-51.79) and females a median L3-SMI of 40.77 (33.73-42.87). Moderate-high and low muscularity groups included 17 and 8 patients, respectively. As for circulating microRNAs, miR-21-5p and miR-133a-3p were up-regulated in patients compared with controls, whereas miR-15b-5p resulted down-regulated in the same comparison (about 30% of control values). Sample clustering by muscularity and sex revealed increased miR-133a-3p and miR-206 only in moderate-high muscularity males. SncRNA profiling in the muscle identified 373 microRNAs and 190 piRNAs (72.5% and 18.7% of raw reads, respectively). As for microRNAs, 10 were up-regulated, and 56 were down-regulated in cancer patients versus controls. Among the 24 dysregulated piRNAs, the majority were down-regulated, including the top two most expressed piRNAs in the muscle (piR-12790 and piR-2106). Network analysis on validated mRNA targets of down-regulated microRNAs revealed miR-15b-5p, miR-106a-5p and miR-106b-5p as main interactors of genes related to ubiquitin ligase/transferase activities.

CONCLUSIONS

These results show dysregulation of both muscle microRNAs and piRNAs in cancer patients compared with controls, the former following a sex-specific pattern. Changes in circulating microRNAs are associated with the degree of muscularity rather than body weight loss.

Exploring the effects of gender and sexual orientation on disordered eating: an EFA to CFA study of the Eating Disorder Examination Questionnaire

Several problems limit our understanding of the ways that gender and sexual orientation influence disordered eating. These include the reliance on measures that have been developed and validated in samples of cisgender heterosexual women, and the lack of confirmed measurement invariance that allows us to meaningfully compare these experiences between groups. This study was an EFA to CFA exploration of the Eating Disorder Examination Questionnaire in a group of heterosexual, bisexual, gay, and lesbian men and women. In total 1638 participants were recruited via adverts in traditional and social media to complete an online survey. A 14-item, three-factor model of the EDE-Q was confirmed as best fitting the data and measurement invariance between groups was ascertained. Sexual orientation influenced disordered eating and muscularity-related thoughts and behaviours in men but not women. Heterosexual men reported more muscularity-related concerns and behaviours, whereas gay men showed more thinness-related concerns and behaviours. Bisexual participants showed a different pattern, highlighting the importance of treating this group individually and not collating all non-heterosexual participants together. Small but significant effects of sexual orientation and gender have an impact on the kinds of disordered eating thoughts and behaviours one might experience, and could influence prevention and treatment. Clinicians may be able to provide more effective and tailored interventions by taking into account gender and sexual orientation in sensitive ways.

Factor structure of the Eating Disorder Examination-Questionnaire (EDE-Q) in adult men with eating disorders

BACKGROUND

Previous investigations on the Eating Disorder Examination-Questionnaire (EDE-Q) factor structures in men have been restricted to non-clinical settings, limiting conclusions about the factorial validity in men with eating disorders (ED). This study aimed to examine the factor structure of the German EDE-Q in a clinical group of adult men with diagnosed ED.

METHODS

ED symptoms were assessed using the validated German version of the EDE-Q. Exploratory factor analysis (EFA) using principal-axis factoring based on polychoric correlations was conducted for the full sample (N = 188) using Varimax-Rotation with Kaiser-Normalization.

RESULTS

Horn's parallel analysis suggested a five-factor solution with an explained variance of 68%. The EFA factors were labeled "Restraint" (items 1, 3-6), "Body Dissatisfaction" (items 25-28), "Weight Concern" (items 10-12, 20), "Preoccupation" (items 7 and 8), and "Importance" (items 22 and 23). Items 2, 9, 19, 21, and 24 were excluded due to low communalities.

CONCLUSIONS

Factors associated with body concerns and body dissatisfaction in adult men with ED are not fully represented in the EDE-Q. This could be due to differences in body ideals in men, e.g., the underestimation of the role of concerns about musculature. Consequently, it may be useful to apply the 17-item five-factor structure of the EDE-Q presented here to adult men with diagnosed ED.

A qualitative investigation of the phenomenology of muscle dysmorphia: Part 2

Muscle dysmorphia (MD) is a mental disorder characterised by preoccupation that one lacks muscularity and/or leanness, leading to substantial functional impairment. This article is the second of a two-part qualitative study examining the phenomenology of MD among 29 adults with diagnosed MD. We used reflexive thematic analysis to generate five themes which capture the role of exercise in the lives of people with MD. In summary, participants were highly motivated by a constant desire to progress their strength and appearance, and bad or missed workouts which threatened to derail their progress were associated with acute mental health impairment. Most participants scheduled rest days and modified workouts, both for muscle building-related goals and to reduce the risk of injuries, but often continued to exercise when sick. Alongside appearance-driven motivations, participants reported exercising for a variety of non-appearance-related reasons, including to structure their daily lives, boost self-esteem, regulate affect, and gain a sense of control from being able to manipulate their body composition. Exercise was often regarded as a core part of one's identity and overwhelmingly perceived as a net positive behaviour. Sample participant resistance training and cardio routines are described in detail within this article.

Muscle dysmorphia symptomatology among a national sample of Canadian adolescents and young adults

The aim of this study was to describe muscle dysmorphia (MD) symptomatology among a large, diverse, and national sample of adolescents and young adults in Canada. Data from the Canadian Study of Adolescent Health Behaviors (N = 2256) were analyzed. MD symptomatology was assessed using the Muscle Dysmorphic Disorder Inventory (MDDI). Men (mean [M] = 33.9, standard deviation [SD] = 8.6) reported significantly greater overall MD symptomatology compared to women (M = 30.1, SD = 7.3) and transgender/gender non-conforming (TGNC; M = 31.5, SD = 7.6) participants. Similarly, the prevalence of clinical MD risk was also highest among men (25.7 %). In regression analyses, participants who identified as South Asian (B 1.97, 95 % confidence interval [CI] 0.41, 3.52) or Middle Eastern (B 2.92, 95 % CI 0.50,5.35), compared to White participants, or identified as gay or lesbian (B 2.65, 95 % CI 1.19, 4.10), compared to heterosexual participants, had greater MD symptomatology. Findings are the first to describe the MD symptomatology among Canadian adolescents and young adults. Health care and public health professionals should be aware of the overall high occurrence of MD symptomatology in this sample, and future research is needed to continue to describe MD among Canadian young people.

Associations between body image patterns and body image-related pathology in sexual minority individuals: A mixture-modeling approach

Body image concerns are associated with disordered eating, body dysmorphic disorder (BDD), and illicit appearance and performance enhancing drug (APED) misuse. Sexual minority individuals are a vulnerable population for body image concerns. Latent profile analyses were used to identify body image patterns in sexual minority men (n = 479) and women (n = 483) and to investigate associations between latent profiles and body image-related pathology. A 5-profile solution demonstrated best fit for men and a 4-profile solution for women. Among women, co-occurring high thinness/muscularity concerns had higher probability of vomiting and dietary restriction than the high thinness/low muscularity concerns profile. The probability of driven exercise did not differ across latent profiles for men and only differed between low thinness/low muscularity and high thinness/high muscularity concerns profiles in women. Men with low thinness/high muscularity concerns had significantly lower probability of vomiting and laxative misuse than all other profiles but did not significantly differ from co-occurring high or moderate thinness/muscularity concerns profiles in binge eating and illicit APED misuse. This study may have implications for future research, treatment, and prevention of body image-related pathology in sexual minority individuals.

Longitudinal relationships between specific domains of interoception and muscle dysmorphia symptoms

Muscle dysmorphia (MD) is a subtype of body dysmorphic disorder (BDD); few risk factors for MD symptom development have been identified. One potential risk factor may be decreased interoceptive sensibility (impaired ability to recognize bodily sensations), which is present across a range of mental disorders. Notably, impaired interoceptive awareness is elevated in populations at-risk for MD. Furthermore, interoception is associated with MD symptoms, and theoretically, interoceptive dysfunction may facilitate engagement in MD symptoms. However, longitudinal research on interoception and MD is scarce, and specific MD symptoms implicated in these relationships are unknown. This study examined longitudinal relationships between specific domains of interoceptive sensibility and MD symptoms. Participants were 255 (26.7% Male; 72.1% Female; 1.2% Non-binary) undergraduates who completed two self-report surveys separated by four weeks. A path model was specified in which seven forms of interoception predicted five MD symptoms. Results suggested that interoceptive sensibility characterized by difficulties attending to bodily sensations and viewing these sensations as distracting predicted MD symptoms like muscle checking, positive attitudes towards using muscle-building substances, and compulsive exercise. Specific forms of impaired interoceptive sensibility may represent a risk factor for MD symptoms. If clinicians can increase the interoceptive abilities of their clients at risk for MD, this may prevent the development of MD symptoms.

"Bulking and cutting" among a national sample of Canadian adolescents and young adults

PURPOSE

First, to characterize the prevalence and incidence of "bulk" and "cut" cycles among Canadian adolescents and young adults. Second, to determine the associations between bulk and cut cycle engagement and drive for muscularity and eating disorder and muscle dysmorphia psychopathology.

METHODS

Data were from the Canadian Study of Adolescent Health Behaviors (2021; N = 2762), a national study of Canadian adolescents and young adults aged 16-30 years (M = 22.9, SD = 3.9). Prevalence and mean incidence of bulk and cut cycles in both the past 12 months and 30 days were estimated. Modified Poisson regressions were estimated to determine the associations between bulk and cut cycle engagement and levels of drive for muscularity and eating disorder and muscle dysmorphia psychopathology.

RESULTS

The sample comprised of 53.5% women, 38.4% men, and 8.1% transgender/gender non-conforming (TGNC) individuals. Nearly half (48.9%) of men and one in five women (21.2%) and TGNC (21.9%) participants reported bulk and cut cycles in the past 12 months. TGNC participants and women reported a greater mean number of bulk and cut cycles completed compared to men. Engagement in bulk and cut cycles was associated with stronger drive for muscularity across the sample, and more severe eating disorder and muscle dysmorphia psychopathology among men and women.

CONCLUSION

Findings underscore the common incidence and accompanying psychopathology of bulk and cut cycles among a community sample of adolescents and young adults in Canada, indicating the need for future research, as well as clinical and public health efforts.

LEVEL OF EVIDENCE

Level V, cross-sectional descriptive study.

A qualitative investigation of the phenomenology of muscle dysmorphia: Part 1

Muscle dysmorphia (MD) is a psychological disorder defined by preoccupation with one's perceived lack of muscularity and/or leanness, causing significant functional impairment. Studies of individuals with diagnosed MD are rare and no large-scale qualitative studies of the disorder exist. We conducted a qualitative study exploring the lived experiences of 29 individuals with diagnosed MD. Using reflexive thematic analysis, we generated five themes capturing the core features of MD. We identified two distinct phenotypes of MD: a "muscular/lean phenotype" focused on both gaining muscle and remaining lean, and a "muscular phenotype" with a sole preoccupation of increasing muscle mass. Participants also described their physique goals as never-obtained "moving goalposts", differed in their desire for muscularity versus leanness, and experienced fluctuations in body dissatisfaction during "cutting" versus "bulking" phases, and pre- versus post-workout. Almost all participants reported avoiding public body exposure and compulsively mirror-checking. Most were rigorous dieters who meticulously tracked their caloric and macronutrient intake, and were obsessive about meeting protein targets. Disruptions to dieting and training were often minimised by compromising their social lives. Low self-esteem appeared a predisposing factor for MD, while social comparison, body image distortion, and integration of MD into one's self-identity may represent maintaining factors. Additional clinically valuable insights into MD's phenomenology are discussed in detail.

Effects of hippotherapy simulation exercise vs. conventional home exercises on muscle strength and balance in people with multiple sclerosis: A randomized controlled trial

OBJECTIVE

To determine the efficacy of hippotherapy simulation exercise on the improvement of muscle strength, balance, spasticity, and quality of life in individuals with multiple sclerosis (MS).

DESIGN

Randomized controlled trial.

SETTING

Outpatient clinic at the rehabilitation clinic of University of Usak, Turkey PARTICIPANTS: Individuals with MS (n = 40) participated in this randomized clinical study.

INTERVENTIONS

Patients in both groups received 36 treatment sessions, 3 times per week for 12 consecutive weeks. Subjects in the study group performed hippotherapy simulation exercise via a hippotherapy simulator device. The control group received conventional home exercises.

MAIN OUTCOME MEASURES

The primary outcome measures included the Monitoring My Multiple Sclerosis (MMMS) Scale, the Berg Balance Scale (BBS), and the Timed Up and Go (TUG) test; quadriceps muscle strength was measured with a dynamometer.

RESULTS

At the level of physical activity, post-intervention MMMS measures showed significant differences in both cases. TUG was significantly lower, and muscle strength and BBS were significantly higher in both post-interventions. No outcome measure showed a significant difference between the groups at both post-intervention and follow-up.

CONCLUSIONS

The results of this study in the field of hippotherapy simulation exercise for people with MS indicate a positive effect on health conditions, balance, mobility skills, and muscle strength. Further studies are necessary to confirm these preliminary results.

Competition or Community? The Backstage Experience of Men in Bodybuilding Competitions

Bodybuilding is an increasingly popular sport in the United States. Across fields of psychology, history, sociology, and anthropology, bodybuilding has been examined as being related to, or as manifestly being, a pathology. Extant work on men who are bodybuilders are often built on the assumption that narcissism, self-doubt, and insecurity are the driving forces for men's involvement. The present study sought to examine the experiences of eleven men who have competed in bodybuilding competitions. In contrast to the dominant academic discourse on bodybuilding as an embodiment of toxic masculinity or as a reaction to underlying feelings of inferiority, the study participants described friendly, supportive competition contexts. That such feelings were found backstage, as opposed to in a gym, strengthens the need for a more nuanced distinction between bodybuilding as a culture, and bodybuilding as a sport. This study disrupts dominant narratives of bodybuilding as pathological and contributes to work on the construction of gender and masculinity in sport. The present work suggests a scholarly approach to men's bodybuilding in an open and nuanced manner that does not focus on pathologizing bodybuilding or competition.

Associations among romantic and sexual partner history and muscle dysmorphia symptoms, disordered eating, and appearance- and performance-enhancing drugs and supplement use among cisgender gay men

This study examined relationship status (e.g., single versus not single) and number of sexual partners in relation to muscularity- and disordered eating-related attitudes and behaviors among 1090 cisgender gay men enrolled in The PRIDE Study in 2018. Participants completed measures assessing muscle dysmorphia (MD) symptoms, disordered eating attitudes and behaviors, and appearance- and performance-enhancing drug or supplement (APEDS) use. In linear regression models adjusting for theoretically relevant covariates, neither relationship status nor number of past-month sexual partners was associated with disordered eating attitudes. In terms of MD symptoms, single (versus not single) relationship status was associated with greater appearance intolerance, and a greater number of sexual partners was associated with greater drive for size and functional impairment. In adjusted logistic regression models, a greater number of past-month sexual partners was associated with use of anabolic-androgenic steroids, synthetic performance-enhancing substances, protein supplements, and creatine supplements, as well as greater likelihood of engaging in compelled/driven exercise. Across all associations, effect sizes were generally small. Overall, results support that inquiring about sexual partners may have utility in evaluating risk for muscularity-oriented attitudes and behaviors among cisgender gay men. Future work will need to replicate these findings, particularly in more diverse samples.

Weight gain attempts and diet modification efforts among adults in five countries: a cross-sectional study

BACKGROUND

Recent research has emphasized a growing trend of weight gain attempts, particularly among adolescents and boys and young men. Little research has investigated these efforts among adults, as well as the specific diet modifications individuals who are trying to gain weight engage in. Therefore, the aims of this study were to characterize the diet modification efforts used by adults across five countries who reported engaging in weight gain attempts and to determine the associations between weight gain attempts and concerted diet modification efforts.

METHODS

Cross-sectional data from the 2018 and 2019 International Food Policy Study, including participants from Australia, Canada, Mexico, the United Kingdom, and the United States (N = 42,108), were analyzed. In reference to the past 12 months, participants reported on weight gain attempts and diet modification efforts related to increased consumption of calories, protein, fiber, fruits and vegetables, whole grains, dairy products, all meats, red meat only, fats, sugar/added sugar, salt/sodium, and processed foods. Unadjusted (chi-square tests) and adjusted (modified Poisson regressions) analyses were conducted to examine associations between weight gain attempts and diet modification efforts.

RESULTS

Weight gain attempts were significantly associated with higher likelihood of each of the 12 forms of diet modification efforts among male participants, and 10 of the diet modification efforts among female participants. Notably, this included higher likelihood of efforts to consume more calories (males: adjusted prevalence ratio [aPR] 3.25, 95% confidence interval [CI] 2.94-3.59; females: aPR 4.05, 95% CI 3.50-4.70) and fats (males: aPR 2.71, 95% CI 2.42-3.03; females: aPR 3.03, 95% CI 2.58-3.55).

CONCLUSIONS

Overall, the patterns of association between weight gain attempts and diet modification efforts may be indicative of the phenomenon of muscularity-oriented eating behaviors. Findings further highlight the types of foods and nutrients adults from five countries may try to consume in attempts to gain weight.

Establishing initial validity and factor structure for the muscularity-oriented eating test in gay men

Eating disorders (EDs) affect men at higher rates than previously estimated, with many traditional ED measures likely underestimating the prevalence of eating and exercise-related pathology among males. The development of the Muscularity-Oriented Eating Test (MOET) represents an important advancement in ED assessment, enabling valid and reliable assessment of muscularity-oriented ED pathology among men. The current study sought to provide initial validity of the MOET among gay men. N = 264 gay men, recruited via MTurk, participated in a brief online survey, completing the MOET and other well-validated measures of eating pathology and body image psychopathology. Factor structure, mean, standard deviation, and intercorrelation between measures were assessed. The MOET demonstrated adequate factor structure, similar to that reported in the initial validation sample, and was significantly correlated with other measures of eating and body image psychopathology. The current study suggests initial validity of the MOET for use among gay men. Future research is needed among younger and more diverse samples of SM men, along with evidence of adequate test-retest reliability and absence of differential item functioning among gay men.

Conformity to masculine norms, masculine discrepancy stress, and changes in muscle dysmorphia symptoms

Muscle dysmorphia (MD) is a severe psychiatric illness; however, little is known regarding risk factors for MD development. Conformity to masculine norms may represent a risk factor for MD, but research has yet to establish temporal ordering for these relationships. Masculine discrepancy stress (distress at not amounting to masculine stereotypes) could represent a mechanism underlying these relationships. Therefore, the current study examined longitudinal relationships between conformity to masculine norms, masculine discrepancy stress, and MD symptoms. Participants were 272 men displaying elevated MD symptoms who completed self-report questionnaires at three timepoints. An autoregressive cross-lagged mediation model was specified to examine relationships between conformity to masculine norms and MD symptoms and test if masculine discrepancy stress mediated these relationships. Masculine discrepancy stress did not mediate relationships between masculine norms and MD symptoms. However, MD symptoms predicted increased masculine discrepancy stress, and conformity to masculine norms was related to MD symptoms. MD symptoms were both a predictor and outcome of masculine norms, and signs for relationships differed on the masculine norm endorsed. Conformity to masculine norms may represent a risk factor and outcome for MD symptoms. If clinicians provide clients with tools to reduce rigid adherence to masculine identities, this may prevent MD symptom development.

The Course of Weight/Shape Concerns and Disordered Eating Symptoms Among Adolescent and Young Adult Males

PURPOSE

Male weight concerns tend to focus on shape and muscularity as opposed to a desire for thinness and remain underdetected by conventional eating disorder assessments. We aimed to describe the longitudinal course of weight concerns and disordered eating behaviors among males across adolescence and young adulthood.

METHODS

We used prospective assessments of 4,489 U S. males, aged 11 to 18 years at baseline of analyses, in the Growing Up Today Study. We assigned mutually exclusive classifications of behaviors consistent with bulimia nervosa (BN), binge eating disorder (BED), purging disorder (PD); high levels of concern with thinness and/or muscularity; and use of muscle-enhancing products. We estimated the probability of maintenance, resolution, or transition to different weight concerns and/or disordered eating behaviors across consecutive survey waves.

RESULTS

Less than 1% of participants met full or partial criteria for BN, PD, or BED at baseline. One-quarter (25.4%, n = 1,137) of males reported high weight concerns during follow-up; nearly all these cases (93.7%, n = 1,065) had high muscularity concerns. The most common transition in concerns or behaviors involved the addition of muscularity concerns to a preoccupation with thinness. Eleven percent of participants used muscle-building products during follow-up. Multi-year product use (23.0% [standard deviation 1.0%] of males who used products) was more common than maintenance of bulimic behaviors (3.0% [.7%] of BN/PD, 10.5% [1.2%] of BED cases).

CONCLUSIONS

Integrating muscularity concerns and product use into health promotion and screening tools may improve prevention and early detection of harmful body image and weight control among adolescent and young adult males.

3D visualisation of psychometric estimates for the ideal male body

Psychological concerns are frequently indexed by psychometric questionnaires but the mental representations that they seek to quantify are difficult to visualise. We used a set of questionnaires designed to measure men's concept of their bodies including: the Drive for Muscularity Scale (DMS; McCreary & Sasse, 2000), the Perceived Sociocultural Pressures Scale (PSPS; Stice, Nemeroff, & Shaw, 1996a), the Body Appreciation Scale (BAS-2; Tylka & Wood-Barcalow, 2015), and the Sociocultural Attitudes Towards Appearance Questionnaire-3 (SATAQ-3; Thompson, van den Berg, Roehrig, Guarda, & Heinberg, 2004). We combined their use with an interactive 3D modelling programme to allow men to create computer-generated representations of their ideal bodies. We used a principal component analysis to extract those shape components of our participants' CGI ideal bodies that were predicted by the questionnaires and reconstructed the body shapes that these questionnaires were capturing. Moving from the lowest to the highest score on both the DMS and SATAQ corresponded with changes in muscularity, particularly muscle mass and definition. This approach allows us to demonstrate the actual body features that are being captured by a particular questionnaire.

Are there associations between religious affiliation and drive for muscularity? A cross-sectional survey of young Muslim women, Christian women and atheist women from Germany

BACKGROUND

Over the last 20 years, society's perception of the ideal female body size in Western cultures has changed from thin to athletic, and many women practice sports to achieve well-toned bodies. However, to date, no study has investigated whether Muslim women who live in a Western country and veil their bodies strive for lean or muscular bodies too. The current cross-sectional survey therefore addressed this question.

METHODS

Veiled Muslim women (n = 70), unveiled Muslim women (n = 50), Christian women (n = 79), and atheist women (n = 68) living in Germany answered several questionnaires assessing engagement in sports, body appreciation, and drive for leanness and muscularity. Univariate and multivariate analyses were conducted to compare the four groups.

RESULTS

The results of univariate and multivariate analyses showed that Muslim women engaged less in sports and veiled Muslim women reported higher body appreciation than did Christian and atheist women. Although the groups did not differ significantly in drive for muscularity, Muslim women showed lower levels of drive for leanness than did Christian and atheist women.

CONCLUSION

Given that Muslim women engaged less in sports and strived less for a lean body compared to Christian and atheist women, a well-toned body might be less important for them. Nevertheless, as being active is beneficial for general health, barriers that prevent Muslim women from engaging in sports should be diminished.

Development and initial psychometric evaluation of the Body Image Matrix of Thinness and Muscularity - Female Bodies

BACKGROUND

Despite evidence that thinness and muscularity are part of the female body ideal, there is not yet a reliable figure rating scale measuring the body image of women which includes both of these dimensions. To overcome this shortcoming, the Body Image Matrix of Thinness and Muscularity - Female Bodies (BIMTM-FB) was developed.

METHODS

The objective of this study is to analyze the psychometric properties of this measure. N = 607 non-clinical women and N = 32 women with eating disorders answered the BIMTM-FB as well as instruments assessing eating disorder symptoms and body image disturbance in order to test the convergent validity of the BIMTM-FB. To assess test-retest reliability, a two-week interval was determined.

RESULTS

The results indicated that the body-fat dimension of the BIMTM-FB correlates significantly with the Contour Drawing Rating-Scale, the Drive for Leanness Scale (DLS) and the Body Appreciation Scale, while the muscularity dimension of the BIMTM-FB was significantly associated with the DLS and the Drive for Muscularity Scale, proving the convergent validity of the BIMTM-FB. High coefficients of test-retest reliability were found. Moreover, the BIMTM-FB differentiated between the clinical sample and the non-clinical controls.

CONCLUSIONS

The BIMTM-FB is a figure rating scale assessing both thinness and muscularity as part of the female body ideal. Due to its high reliability and validity, the BIMTM-FB can be recommended in research and practice.

A review and integrated theoretical model of the development of body image and eating disorders among midlife and aging men

Etiological models of the development of eating disorders among midlife and aging men are lacking. The present study provides a review and integration of existing theoretical frameworks and empirical data relevant to the examination of eating pathology in this population and introduces an integrated model of risk and protective factors for the development of eating disorder symptoms. Several etiological models of eating pathology that have gained some empirical support, or present relevance to this population, are briefly reviewed including sociocultural theory, objectification theory, social identity theory, positive body image and the developmental theory of embodiment, and existential and terror management theory, and finally biologically based theories. In addition, these frameworks were extended to account for developmental and gender-specific factors that may influence the development of eating disorders. An integrated model of risk and protective factors that brings together critical elements of these extended theoretical frameworks is presented, with the goal of guiding and stimulating research in this neglected group.

Sociocultural factors affecting drive for muscularity among male college students in Malaysia

Compared with females, little research on muscularity and the sociocultural influences on this domain has been conducted with males in non-Western societies. The current study explored these sociocultural predictors of drive for muscularity among Malaysian male college students, specifically in terms of ethnicity and exposure to media (i.e., Internet and social media). In total, 166 male college students from two universities in Kuala Lumpur were asked to rate the questionnaires as to muscularity-oriented attitudes and behaviours. Multivariable general linear model analyses revealed that being Chinese was a strong predictor of muscularity-oriented attitudes and behaviours. In addition, modern media, particularly, Internet use and the number of followers on Instagram, was found to significantly predict males' drive for muscularity. Overall findings suggest that males of particular ethnic groups may be at higher risk for negative body image compared to the other ethnic populations and modern media use may accelerate drive for muscularity, which may also in turn place males at higher risk for excess muscularity-oriented thoughts and behaviours.

Intentional weight gain efforts among young Canadian adults aged 17-32 years

Research related to body weight management often focuses on weight loss but attempts to gain weight may be common given societal ideals related to body shape and size. The objectives of this study were to examine the prevalence and correlates of intentional weight gain attempts and to characterize weight gain strategies reported among young Canadian adults. Cross-sectional data were drawn from a 2017 online survey of young adults, aged 17 to 32 years, recruited from five large cities (n=976, 493 men and 483 women). The prevalence of weight gain attempts and specific strategies used were estimated, with multivariable logistic regression used to examine correlates of intent to gain weight. Over one in five men (23.1%) and approximately one in twenty women (6.0%) reported attempting to gain weight in the past 12 months. Men, those who perceived themselves as underweight (compared to "just about right"), and those who reported one or more racial/ethnic identity or did not state their race/ethnicity (compared to white only) had higher odds of reporting attempting to gain weight. Individuals who perceived themselves as overweight or who self-reported heights and weights corresponding to a BMI between 25 and 29.9 had lower odds of reporting attempting to gain weight. Those attempting to gain weight reported using three strategies on average, with the most prevalent among both men and women including eating more overall, eating more protein, and exercising/weightlifting. The results suggest that, while less common than dieting, weight gain attempts are not rare, especially among young men.

The importance of motivational orientation towards the muscular ideal versus the stigmatised burdensome body in male body dissatisfaction

Internalisation of the muscular ideal is a vulnerability factor for body dissatisfaction in males. It is unclear, however, whether body dissatisfaction results from approach towards the muscular ideal versus fear of the stigmatised burdensome body. The current study sought to address this gap by assessing both approach and avoidance motivation regarding muscular and non-muscular bodies, respectively, and evaluating the unique associations between approach-avoidance tendencies and body dissatisfaction. Eighty-three male undergraduate students completed an implicit measure of approach-avoidance tendencies, the Stimulus Response Compatibility task, and a self-report measure of trait body dissatisfaction. Results revealed that participants were quicker to approach than to avoid muscular bodies; however, there were no differences in approach vs. avoidance tendencies regarding non-muscular bodies. Furthermore, in a multiple regression model comprising motivational bias scores regarding muscular and non-muscular bodies, only an approach bias towards muscular bodies predicted unique variance in body dissatisfaction. These findings are novel in showing an implicit approach motivation towards the muscular ideal in male undergraduates. Furthermore, in this population, motivational orientation towards the muscular ideal, versus the stigmatised burdensome body, seems to be more tightly associated with body dissatisfaction.

Including body composition in MELD scores improves mortality prediction among patients awaiting liver transplantation

BACKGROUND & AIMS

The Model for End-stage Liver Diseases (MELD) is widely accepted for prioritizing candidates awaiting liver transplantation (LT). However, MELD scores do not reflect the severity of the nutritional or functional status of patients with cirrhosis.

METHODS

This retrospective study analyzed data from 173 patients who were waitlisted for LT at our institution between April 2006 and December 2016. By including skeletal muscle mass, muscle quality and visceral adiposity evaluated using plain computed tomography imaging in MELD scores, we developed body composition-MELD (BC-MELD), and investigated its impact on the prediction of mortality among patients awaiting LT.

RESULTS

The equation generated using Cox regression analysis was as follows: BC-MELD = MELD score + 3.59 × low SMI + 5.42 × high IMAC + 2.06 × high VSR. (IMAC, intramuscular adipose tissue content; SMI, skeletal muscle mass index; VSR, visceral-to-subcutaneous adipose tissue area ratio). The median BC-MELD score was 17.4 and the area under the receiver operating characteristic curve (AUC) revealed a cut-off BC-MELD score of 21.4 (AUC = 0.835, P < 0.001, sensitivity 87.5%, specificity 70.7%). Waitlist mortality in patients with high BC-MELD was significantly higher in all tested cohorts (P < 0.001) and among patients with lower conventional MELD scores (<15) (P < 0.001). The discriminatory power was significantly better for BC-MELD than MELD scores (AUC; 0.835 vs. 0.732, P = 0.001 for 3-month, AUC; 0.765 vs. 0.671, P = 0.002 for 6-month, AUC; 0.716 vs. 0.615, P < 0.001 for 12-month, AUC; 0.636 vs. 0.584, P = 0.014 for overall mortality).

CONCLUSIONS

BC-MELD is the first to include not only muscularity but also visceral adiposity. It predicted waitlist mortality more accurately than the conventional MELD score. A new allocation system based on BC-MELD might lead to better outcomes for patients with cirrhosis awaiting LT.

Gender differences in responses to thin, athletic, and hyper-muscular idealized bodies

Recent evidence suggests that the ideal female body has shifted from an ultra-thin image toward one that is both thin and toned, or muscular. Furthermore, the ideal male body may be more athletic, characterized by moderate muscularity combined with leanness, than bodybuilder-muscular. Thus, we experimentally examined women's (n = 92) and men's (n = 106) cognitive processing style in response to idealized body types, i.e., thin images, athletic images (thin and muscular), or hyper-muscular images (moderately thin and extremely muscular). Results revealed that women in the athletic condition were the most likely to generate negative social comparisons. Women in the thin condition were more likely to generate counter-arguments compared to women in the other two conditions. Men in the hyper-muscular condition were more likely to generate counter-arguments than men in the other two conditions. Further, among women in the thin condition, negative social comparisons were inversely related to body appreciation but positively related to internalization of appearance ideals. Findings confirm that the athletic ideal likely poses problems for women's body image. Both women and men seemed to be able to "talk back" when exposed to their gendered body ideal.

Making gains: Hypermuscularity and objectification of male and female Olympic athletes in Sports Illustrated across 60 years

Female athletes have disproportionately lacked media coverage. The depictions that do exist have typically been sexualized, which has been described as trivializing their accomplishments. It is unclear, however, to what extent the gender differences in the amount and types of media representations of athletes are evolving with time. In addition, trends in increasing muscularity in media depictions of athletes have not been examined. The aims of this study were therefore to examine gender differences in levels of muscularity and gendered and objectified portrayals of summer Olympic athletes (N = 78) depicted on the covers of Sports Illustrated over the last 60 years. Findings from this content analysis suggested that while female athletes are achieving greater media representation, significant gender differences still exist, with female athletes more likely to be depicted in sexually objectified ways. Findings also revealed that athletic bodies portrayed in the media have progressively become more muscular. Further efforts to close the gender gaps in depictions of athletes in the media are warranted.

Supraphysiologic-dose anabolic-androgenic steroid use: A risk factor for dementia?

Supraphysiologic-dose anabolic-androgenic steroid (AAS) use is associated with physiologic, cognitive, and brain abnormalities similar to those found in people at risk for developing Alzheimer's Disease and its related dementias (AD/ADRD), which are associated with high brain β-amyloid (Aβ) and hyperphosphorylated tau (tau-P) protein levels. Supraphysiologic-dose AAS induces androgen abnormalities and excess oxidative stress, which have been linked to increased and decreased expression or activity of proteins that synthesize and eliminate, respectively, Aβ and tau-P. Aβ and tau-P accumulation may begin soon after initiating supraphysiologic-dose AAS use, which typically occurs in the early 20s, and their accumulation may be accelerated by other psychoactive substance use, which is common among non-medical AAS users. Accordingly, the widespread use of supraphysiologic-dose AAS may increase the numbers of people who develop dementia. Early diagnosis and correction of sex-steroid level abnormalities and excess oxidative stress could attenuate risk for developing AD/ADRD in supraphysiologic-dose AAS users, in people with other substance use disorders, and in people with low sex-steroid levels or excess oxidative stress associated with aging.

Low body esteem and dietary restraint among 7-year old children: The role of perfectionism, low self-esteem, and belief in the rewards of thinness and muscularity

Body image concerns and dietary restraint have been shown to emerge among young children (aged 5 to 8 years). However, to date, little is known regarding the way in which individual characteristics and endorsement of sociocultural appearance ideals are associated with these concerns and behaviors in this age group. The aim of the current study was to examine perceived rewards of thinness and muscularity as a mediator of the relationships between personality traits (perfectionism and self-esteem), and body esteem and dietary restraint among 7-year-old children. Participants were 261 children, Mage (SD) = 7.46 (0.32), assessed during interview on a range of scales measuring variables of interest. Findings revealed that, with the addition of direct pathways leading to dietary restraint, the model was a good fit to the data. Furthermore, multi-group analyses revealed no gender differences. These results highlight the role of children's individual personality characteristics as well as the degree to which they uphold thin and muscular appearance ideals in body image and eating concerns in 7 year olds. Additional efforts should be made to engage this age group with prevention resources and to target personality characteristics as well as beliefs in the rewards of appearance ideals.

Prospective predictors of body dissatisfaction, drive for thinness, and muscularity concerns among young women in France: A sociocultural model

The aim of this study was to explore a prospective sociocultural model of the influence of media, peers, and partners on body dissatisfaction, drive for thinness, and muscularity concerns in a sample of young women in France. A sample of 192 undergraduate women with a mean age of 20.97 years (SD = 2.69) completed a questionnaire at two time-points, 12 months apart, assessing media and interpersonal influences, appearance comparison, body dissatisfaction, drive for thinness, and muscularity concerns. The final model highlighted that media and interpersonal influences (from peers and romantic partners) were associated over time with increased body dissatisfaction, drive for thinness, and muscularity concerns one year later, via appearance comparison. Sociocultural influences towards both thinness and muscularity may contribute to increases in body image concerns and risky body change behaviors in young women in France.

Preferences for being muscular and thin in 6-year-old boys

Body dissatisfaction emerges at an early age in childhood. However, the unique experiences of young boys regarding muscularity have not been examined. Interview responses were collected from 101 6-year-old boys to examine muscularity- and thinness-oriented body dissatisfaction. Both muscularity- and thinness-oriented body dissatisfaction were evident; boys on average selected ideal figure sizes significantly more muscular and significantly thinner than current figures. In addition, a significantly greater proportion of boys wanted to be more muscular (32.6%) than less muscular (16.8%), and thinner (20.8%) rather than larger-fatter (8.9%). Further, boys perceived significantly greater rewards from muscularity than from thinness. Findings demonstrate that muscularity and thinness-oriented body dissatisfaction is present in a substantial proportion of young boys, although a greater proportion are dissatisfied with muscularity than with thinness, suggesting that examination of body image in young boys needs to focus on muscularity dimensions as well as thinness-fatness dimensions.

Orthorexia symptoms correlate with perceived muscularity and body fat, not BMI

PURPOSE

This study explored how different body-type measures relate to orthorexia symptomatology.

METHOD

Participants were 465 undergraduates, who completed an online survey with self-reported height and weight items, a muscularity figure rating scale, a body fat figure rating scale, and the Eating Habits Questionnaire (EHQ; Gleaves, Graham, & Ambwani, 2013).

RESULTS

BMI was not significantly related to any of the EHQ subscale scores. In contrast, muscularity rating was positively related to all EHQ subscale scores: Behaviors (p < .001), Problems (p = .014), and Feelings (p = .003). Additionally, body fat rating was negatively correlated with two EHQ subscale scores: Behaviors (p < .001) and Feelings (p = .008). None of these relationships varied as a function of gender.

CONCLUSION

These findings suggest that orthorexia symptomatology, while unrelated to BMI, is greater for individuals who perceive themselves as having a relatively muscular, lean body type.

LEVEL OF EVIDENCE

Level V, descriptive cross-sectional study.

Negative Body Attitudes and Sexual Dissatisfaction in Men: The Mediating Role of Body Self-Consciousness During Physical Intimacy

Previous research indicated that negative attitudes about the body and appearance are common among men and demonstrated that negative body attitudes are associated with negative sexual experiences. The present study investigated the association between body attitudes and sexual dissatisfaction and the mediating role of body self-consciousness during physical intimacy. In a cross-sectional design, 201 Dutch men completed an online survey regarding body attitudes toward muscularity, body fat, height, and genitals, body self-consciousness during physical intimacy, and sexual dissatisfaction. Hypotheses were tested using correlation analyses and a mediation analysis with body attitudes as predictors, body self-consciousness as mediator, and sexual dissatisfaction as outcome. Correlation analyses showed that negative body attitudes and body self-consciousness during physical intimacy were significantly related to sexual dissatisfaction. The mediation analysis revealed that negative attitudes toward muscularity, body fat, and genitals had indirect effects on sexual dissatisfaction through body self-consciousness during physical intimacy. Negative attitudes toward genitals additionally had a direct effect on sexual dissatisfaction. These findings indicate that body image interventions focused on male body attitudes may be beneficial in improving men's body image, which may ultimately increase sexual satisfaction.

Idealised media images: The effect of fitspiration imagery on body satisfaction and exercise behaviour

Recent studies have documented a shift in the cultural ideal of physical attractiveness, with women subscribing to a visibly toned ideal that emphasises health and fitness. The present study experimentally investigated the impact of athletic and muscular fitness-idealised images compared to traditional thin ideal images on women's body dissatisfaction and exercise behaviour, under the framework of Social Comparison Theory. Participants were 106 female undergraduate students randomly assigned to view one of three sets of images (thin ideal, athletic ideal, or muscular ideal) followed by a bout of exercise. Acute exposure to athletic ideal and thin ideal images led to increased body dissatisfaction, but exposure to muscular ideal images did not. Relative to thin ideal images, fitness-idealised images did not motivate participants to engage in higher levels of exercise suggesting that this type of fitness inspiration might not motivate actual exercise behaviour.

Precarious manhood and muscularity: Effects of threatening men's masculinity on reported strength and muscle dissatisfaction

The precarious manhood perspective proposes that men respond with aggression when they experience threats to their masculinity. Consistent with this view, we hypothesized that men would represent themselves as stronger and more formidable after their masculinity was threatened. A recent study, however, found that men reported less physical strength when threatened (Hunt, Gonsalkorale, & Murray, 2013). In the current two studies (Ns=193; 450), men were given false feedback about whether they were substantially less masculine (masculinity threatened) or more masculine than average (masculinity reassured). Men reported how much weight they could curl, how many push-ups they could complete, and/or measures of satisfaction with muscularity. In most analyses, threatened men reported greater strength than reassured men. Effects of masculinity threat on muscle dissatisfaction varied by outcome measure. The studies highlight the importance of replication studies, and of using experimental approaches to understand connections between precarious manhood and male body image.

Men, Muscles, and Eating Disorders: an Overview of Traditional and Muscularity-Oriented Disordered Eating

PURPOSE OF REVIEW

There is growing recognition that eating disorder (ED) symptoms, particularly those of a muscularity-oriented nature, are more common in men than previously understood. The purpose of the current review is to describe contemporary directions and implications of research on traditional and muscularity-oriented ED symptoms among males.

RECENT FINDINGS

Evidence indicates that ED symptoms occur in a substantial minority of men. Importantly, recent research has focused on muscularity-oriented body image and disordered eating in males, demonstrating the prevalence, correlates, and consequences of maladaptive muscularity-oriented attitudes and behaviors. A growing number of assessments are available to measure these constructs in males, and preliminary treatment considerations have begun to be addressed in the literature. Research on male EDs and body image is increasingly focusing on muscularity-oriented manifestations. Continued empirical work will be critical to improve our understanding of the onset, maintenance, and treatment of muscularity-oriented disordered eating in males.

Multifidus Degeneration, A New Risk Factor for Lumbar Spinal Stenosis: A Case-Control Study

OBJECTIVES

To analyze whether multifidus degeneration has a relationship with degenerative lumbar spinal stenosis (LSS).

MATERIALS AND METHODS

Clinical data of 40 patients with LSS were analyzed retrospectively. Moreover, 40 healthy people were selected as controls. Subjects of both groups underwent a 1.5-T lumbar spinal magnetic resonance imaging scan in our hospital, and then the multifidus muscularity, fatty infiltration ratio, and bilateral asymmetry at L4/5 level on magnetic resonance imaging were measured with ImageJ software to analyze and compare the multifidus parameters between the 2 groups.

RESULTS

Compared with the control group, the multifidus muscularity was lower, fatty infiltration ratio was greater, and muscle asymmetry was more significant at the L4/5 level in patients with LSS, and the difference between the 2 groups was statistically significant.

CONCLUSIONS

Multifidus degeneration, including reduced volume, increased fatty infiltration, and bilateral muscle asymmetry, has an association with LSS.

Efficient TALEN-mediated myostatin gene editing in goats

Background

Myostatin (MSTN) encodes a negative regulator of skeletal muscle mass that might have applications for promoting muscle growth in livestock. In this study, we aimed to test whether targeted MSTN editing, mediated by transcription activator-like effector nucleases (TALENs), is a viable approach to create myostatin-modified goats (Capra hircus).

Results

We obtained a pair of TALENs (MTAL-2) that could recognize and cut the targeted MSTN site in the goat genome. Fibroblasts from pedigreed goats were co-transfected with MTAL-2, and 272 monoclonal cell strains were confirmed to have mono- or bi-allelic mutations in MSTN. Ten cell strains with different genotypes were used as donor cells for somatic cell nuclear transfer, which produced three cloned kids (K179/MSTN^−/−, K52-2/MSTN^+/−, and K52-1/MSTN^+/+).

Conclusions

The results suggested that the MTAL-2 could disrupt MSTN efficiently in the goat genome. The mutated somatic cells could be used to produce MSTN-site mutated goats without developmental disruption. Thus, TALENs is an effective method for accurate genome editing to produce site-modified goats.

Electronic supplementary material

The online version of this article (doi:10.1186/s12861-016-0126-9) contains supplementary material, which is available to authorized users.

Young men's endorsement and pursuit of appearance ideals: The prospective role of appearance investment

Appearance investment has been proposed as a risk factor for the development of body dissatisfaction. Despite this, few studies have explored men's investment in their appearance. The aim of the present study was therefore to examine appearance investment as a prospective predictor of young men's endorsement and pursuit of appearance ideals. A community sample of 187 young men participated in a study at ages 21 and 24. Hierarchical multiple regressions revealed that appearance investment, as hypothesized, was a prospective predictor of increases in leanness orientation, media-ideal internalization, and muscularity behaviors. However, appearance investment did not predict increases in muscularity dissatisfaction. The present findings highlight the importance of including appearance investment in sociocultural models of the development of men's body image, and suggest that appearance investment may be an important target variable to consider when designing body dissatisfaction prevention and intervention programs tailored to young men.

Go big or go home: A thematic content analysis of pro-muscularity websites

Existing content analyses of pro-eating disorder web content have focused on thinness-oriented eating disorder pathology. With the increasing prevalence of muscularity-oriented body image concerns, we conducted a systematic content analysis of 421 active pro-muscularity websites including static content websites, blogs, and online forums. Emergent coding methods were utilized (Cohen's kappa range=.78-.88), and eight distinct thematic categories were identified: rigid dietary practices (26.2%), rigid exercise rules (18.4%), the broader benefits of muscularity (16.1%), the encouragement of the drive for size (15.9%), the labeling of non-ideal body (11.4%), marginalizing other areas of life (6.1%), muscle enhancing substances (3.3%), and minimizing medical risk (2.6%). Pro-muscularity websites provide explicit material surrounding potentially non-healthful muscularity-oriented eating and exercise practices. Clinician awareness of the potentially non-healthful behaviors involved in the pursuit of muscularity may enhance the detection and treatment of male eating disorders, in particular.

Putative Androgen Exposure and Sexual Orientation: Cross-Cultural Evidence Suggesting a Modified Neurohormonal Theory

INTRODUCTION

According to neurohormonal theory, prenatal androgens are key determinants of sexual orientation. As a reputed marker for prenatal androgens, the 2D:4D finger length ratio has been used in more than a dozen studies to test the hypothesis that prenatal androgens influence sexual orientation. Findings have been very inconsistent.

AIM

The present study sought to retest the hypothesis that 2D:4D and sexual orientation are related is a manner consistent with neurohormonal theory.

METHODS

A 2D:4D measure (of the right hand) along with four additional somatic markers of androgen exposure (height, physical strength, muscularity, and athletic ability) with samples of college students in Malaysia (N = 2,058) and the United States (N = 2,511). The five androgen measures were factor analyzed, resulting in a two-factor solution: Factor 1 consisted of strength, muscularity, and athletic ability (the muscular coordination factor), and Factor 2 was comprised of the r2D:4D and adult height (the bone growth factor).

MAIN OUTCOME MEASURES

Sexual orientation was measured by asking each respondent the extent to which they were sexually attracted to males and the extent to which they were sexually attracted to females, both on 11-point scales.

RESULTS

When the countries and sexes were analyzed separately, neither the r2D:4D measure nor Factor 2 correlated with sexual orientation to significant degrees. Instead, it was the muscular coordination factor that correlated the best. Support was found for the hypothesis that prenatal androgens influence sexual orientation, but the nature of these influences was more complex than neurohormonal theory predicted.

CONCLUSION

A modified theory is needed and presented to accommodate the results from this study.

Media internalization and conformity to traditional masculine norms in relation to body image concerns among men

Previous studies have separately examined conformity to masculine norms and internalization of body ideals in the media in relation to the drive for muscularity (DM). This study was designed to examine these factors together in relation to DM, and further examine how they may differ in relation to drive for thinness (DT) and drive for leanness (DL). Participants were 284 Australian males between ages 18 and 42. They completed validated measures that assessed DM, DT, DL, male gender role norms, and internalization of body ideals. The findings showed that internalization of body ideals mediated the relationship between masculine role norms and body image in the case of both DM and DL. However, masculine norms and internalization were independent predictors of DT. Our findings contribute to further understanding of the roles that the media and masculine norms have in shaping men's drive for muscularity, leanness, and thinness. Longitudinal research is needed to confirm the nature and direction of these relationships.

The effect of thin and muscular images on women's body satisfaction

A substantial body of research documents that exposure to images depicting a "thin ideal" body figure effects women's state-oriented body satisfaction. However, there is evidence that the societal ideal body figure of females is evolving to be not just thin, but also muscular or toned. Therefore, the purpose of this research was to test the effect of exposure to ideal body figures that are both thin and muscular on female state body satisfaction. Researchers recruited female participants (N=366) from an online community (Amazon's Mechanical Turk) and randomly assigned them to view images in one of four conditions: thin, thin and muscular, thin and hypermuscular, and control (images of cars). Results indicated that state-oriented body satisfaction decreased in the thin condition and thin and muscular condition, but not the hypermuscular or control conditions. These findings have implications for clinical initiatives as well as future research.

The connection of teasing by parents, siblings, and peers with girls' body dissatisfaction and boys' drive for muscularity: the role of social comparison as a mediator

In this cross-sectional study, we focused on three research questions pertaining to the connections between appearance-related teasing and body image during adolescence. First, we investigated how parental appearance-related teasing of adolescents was associated with teasing by siblings. Second, we examined how teasing by mothers, fathers, siblings, and peers was individually associated with adolescent girls' body dissatisfaction and boys' drive for muscularity. We included BMI as a possible moderator in these analyses. Third, we tested the role of appearance-related social comparison as a mediator of the relations between teasing and body image. Self-report survey data were collected from 80 girls and 78 boys in a Midwestern U.S. middle school. Results from correlational and odds-ratio analyses indicated that teasing by mothers and fathers was strongly associated with teasing by siblings. Additionally, in regression analyses, mothers', fathers', siblings', and peers' teasing were separately associated with girls' body dissatisfaction and boys' drive for muscularity. Social comparison partially mediated the relationship between all sources of teasing and girls' body dissatisfaction as well as the relationship between mothers' and fathers' teasing and boys' drive for muscularity. Social comparison fully mediated the link between peers' teasing and boys' drive for muscularity. Researchers and clinicians should be aware of how family members and peers can influence adolescents' development of body image concerns through teasing behaviors and by social comparison.

Development and validation of the Male Body Talk Scale: a psychometric investigation

This paper details the development of the Male Body Talk (MBT) scale and five studies supporting the psychometric soundness of scores on this new measure. Participants were 18-65-year-old men recruited via Amazon's Mechanical Turk, introductory psychology courses, and snowball sampling. The MBT scale assesses the frequency with which men engage in negatively valenced body-related conversations with others. Two subscales were identified through a combination of exploratory and confirmatory factor analysis. The Muscle Talk subscale assesses men's tendency to express concerns regarding degree of muscularity and being too small. The Fat Talk subscale assesses men's tendency to express concerns regarding level of body fat and being overweight. Scores on the MBT scale demonstrated strong internal consistency and moderate test-retest reliability. Evidence of convergent, discriminant, and incremental validity of scores on the MBT scale is presented. This new measure is a useful tool for examining how often men engage in negative body talk.

Similar photoperiod-related birth seasonalities among professional baseball players and lesbian women with an opposite seasonality among gay men: Maternal melatonin may affect fetal sexual dimorphism

Based on pre-mid-20th-century data, the same photoperiod-related birth seasonality previously observed in schizophrenia was also recently found in neural-tube defects and in extreme left-handedness among professional baseball players. This led to a hypothesis implicating maternal melatonin and other mediators of sunlight actions capable of affecting 4th-embryonic-week developments including neural-tube closure and left-right differentiation of the brain. Here, new studies of baseball players suggest that the same sunlight actions could also affect testosterone-dependent male-female differentiation in the 4-month-old fetus. Independently of hand-preferences, baseball players (n=6829), and particularly the stronger hitters among them, showed a unique birth seasonality with an excess around early-November and an equally significant deficit 6 months later around early-May. In two smaller studies, north-American and other northern-hemisphere born lesbians showed the same strong-hitter birth seasonality while gay men showed the opposite seasonality. The sexual dimorphism-critical 4th-fetal-month testosterone surge coincides with the summer-solstice in early-November births and the winter-solstice in early-May births. These coincidences are discussed and a "melatonin mechanism" is proposed based on evidence that in seasonal breeders maternal melatonin imparts "photoperiodic history" to the newborn by direct inhibition of fetal testicular testosterone synthesis. The present effects could represent a vestige of this same phenomenon in man.

Body Image Concerns and Contingent Self-Esteem in Male and Female College Students

Body dissatisfaction in females, and to a lesser extent males, is associated with low self-esteem, depression, and eating disorders. This research examined gender as a moderator of the association between contingent self-esteem and body image concerns, including weight and muscularity. Participants included 359 (59.1% female) heavy drinking first-year U.S. undergraduate students who completed a survey assessing health-related risk behaviors. Hierarchical multiple regression was used to examine relations among gender, contingent self-esteem, and body image. Females reported higher levels of contingent self-esteem and greater concerns about their weight, although males reported a greater drive for muscularity. The relationship between contingent self-esteem and weight concerns was stronger among females, and for males, greater contingent self-esteem was associated with a greater drive for muscularity.