Muscular Body Research Articles

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

BackgroundOver 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.MethodsVeiled 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.ResultsThe 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.ConclusionGiven 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.

Is active sitting on a dynamic office chair controlled by the trunk muscles?

Today's office chairs are not known to promote active sitting or to activate the lumbar trunk muscles, both of which functions are ergonomically recommended. This study investigated a newly developed dynamic office chair with a moveable seat, specifically designed to promote trunk muscle controlled active sitting. The study aimed to determine the means by which the seat movement was controlled during active sitting. This was accomplished by quantifying trunk and thigh muscular activity and body kinematics. Additionally, the effect of increased spinal motion on muscular activity and body kinematics was analysed. Ten subjects were equipped with reflective body markers and surface electromyography on three lumbar back muscles (multifidus, iliocostalis, longissimus) and two thigh muscles (vastus lateralis and medialis). Subjects performed a reading task during static and active sitting in spontaneous and maximum ranges of motion in a simulated office laboratory setting. The temporal muscle activation pattern, average muscle activity and body segment kinematics were analysed and compared using Friedman and post-hoc Wilcoxon tests (p≤0.05). Active sitting on the new chair significantly affected the lumbar trunk muscles, with characteristic cyclic unloading/loading in response to the seat movement. Neither thigh muscle activity nor lateral body weight shift were substantially affected by active sitting. When participants increased their range of motion, the lumbar back muscles were activated for longer and relaxation times were shorter. The characteristic activity pattern of the lumbar trunk muscles was shown to be the most likely dominant factor in controlling seat movement during active sitting. Consequently, the new chair may have a potential positive impact on back health during prolonged sitting. Further studies are necessary to analyse the frequency and intensity of active sitting during daily office work.

Maasai on the phone: materiality, tourism, and the extraordinary in Zanzibar

Thousands of Maasai men have been flocking in recent years to the island of Zanzibar to take part in the burgeoning tourism industry. Many are employed as guards and security personnel. Others roam the beaches, selling souvenirs and touting tourist services, while some are involved in sex-tourism. In this article, we show how these men skillfully employ their traditional materiality: red robes, swords, daggers, clubs, beaded sandals and jewelry, as well as their own muscular bodies, so as to construct an extraordinary image, which they use to attract the attention of tourists and promote their businesses. Concomitantly, their use of modern material objects, such as mobile phones and stylish sunglasses, undermines their extraordinary image, making their presence mundane and even disturbing, to the extent of being accused by some Tanzanians and tourists of faking Maasai identity. We conclude by arguing that material objects and the ways in which they are used may define people as ordinary and extraordinary at the same time. Materiality therefore underlies a complex, dynamic, and ambiguous perception of the extraordinary in contemporary tourism.

Ethiopian traditional dance alter the health-related physical fitness traits of high school students

The purpose of this study was to evaluate the effect of Tigray regional state traditional dances on health-related physical fitness traits among high school students in Ethiopia. To achieve the purpose of this study, 100 high school students were selected randomly. And their age was 15.5±1.1 years. The selected participants were categorized into the experimental group consists of four Traditional dances that were Awris, Hura, Kuda, and Shediva and the control group with twenty subjects in each. The experimental group performed traditional dances for 16 weeks three days per week whereas participants in the control group were informed to follow their usual daily activity. All participants were tested on selected criterion measures on muscular strength, flexibility, cardiovascular endurance and body composition before and after the 16 weeks of the training period. The data about the variables in this study were statistically examined using ANOVA for each variable separately, whenever the ‘F’ ratio of adjusted post-test was found to be significant, the Scheffe’s test was used to determine the paired mean differences. The level of significance was fixed at 0.05. Following the 16-weeks traditional dance training, a significant change was observed on muscular strength, flexibility, and cardiovascular endurance, but there was no significant improvement in body composition as compares to the experimental groups with the control group. Therefore it can be concluded that Tigray traditional dance training program can notably improve physical fitness level of high school students.

Muscular Strength, Functional Fitness, Body Composition, and Quality of Life after 12 Weeks of Detraining in Older Females

Aims The purpose of this study was to investigate the effect of a 12-week strength training, and 3 months of detraining on physical fitness, body composition, and quality of life. Methods: Twenty women underwent assessments pre- and post-training, and after cessation of training. The measurements included waist-to-hip ratio, muscle mass, fat mass, leg press and seated row strength, functional fitness (SFT), and quality of life physical component score (PCS) and mental component score (MCS). Results: Significant interaction (p < 0.01) was found in all tests except for the PCS. The subjects in the EX group significantly improved in all tests (p < 0.01) from pre- to post-training. However, during the detraining, strength, SFT, and MSC significantly worsened from post- to detraining (p < 0.01). Body composition, except for muscle mass, remained unchanged. Conclusions: It seems that body composition persists for prolonged times, compared to performance characteristics. However, the results should be interpreted with caution, because improvements in body composition had small effects (g = ∼0.20–0.32).

Physical Fitness Promotion among Adolescents: Effects of a Jump Rope-Based Physical Activity Afterschool Program.

The major purpose of this study was to examine the effects of a jump rope-based physical activity afterschool program on middle school students’ physical fitness. Sixty students (Mage = 13.37, SD = 0.58; 53.3% female) participated in a 12-week jump rope-based afterschool program (45 min/time, three times/week). Participants were randomly assigned to three groups: (a) freestyle rope skipping (N = 20), traditional jump rope (N = 20), and a control group (N = 20). Physical fitness tests, including muscular strength (standing long jump, right-hand grip, and left-hand grip), flexibility, body composition, and bone mineral density (BMD) were measured in pre- and post-tests. A 2 (time) × 3 (groups) repeated measure multivariate analysis of variance (MANOVA) was performed. The results found significant improvements in muscular strength (standing long jump, right-hand grip, and left-hand grip) in both intervention groups (p < 0.001; ds = 0.2–0.44). Only the freestyle rope skipping group had increased BMD (p < 0.05, d = 0.33). Compared to the traditional jump rope, the freestyle rope skipping group showed significantly higher improvement in flexibility (p < 0.05, d = 0.83). These findings suggest that the jump rope-based afterschool program with freestyle rope skipping would be more effective than traditional jump rope to promote physical fitness performance among adolescents.

Performances of Adaptive MultiBLUP, Bayesian regressions, and weighted-GBLUP approaches for genomic predictions in Belgian Blue beef cattle

BackgroundGenomic selection has been successfully implemented in many livestock and crop species. The genomic best linear unbiased predictor (GBLUP) approach, assigning equal variance to all SNP effects, is one of the reference methods. When large-effect variants contribute to complex traits, it has been shown that genomic prediction methods that assign a higher variance to subsets of SNP effects can achieve higher prediction accuracy. We herein compared the efficiency of several such approaches, including the Adaptive MultiBLUP (AM-BLUP) that uses local genomic relationship matrices (GRM) to automatically identify and weight genomic regions with large effects, to predict genetic merit in Belgian Blue beef cattle.ResultsWe used a population of approximately 10,000 genotyped cows and their phenotypes for 14 traits, mostly related to muscular development and body dimensions. According to the trait, we found that 4 to 25% of the genetic variance could be associated with 2 to 12 genomic regions harbouring large-effect variants. Noteworthy, three previously identified recessive deleterious variants presented heterozygote advantage and were among the most significant SNPs for several traits. The AM-BLUP resulted in increased reliability of genomic predictions compared to GBLUP (+ 2%), but Bayesian methods proved more efficient (+ 3%). Overall, the reliability gains remained thus limited although higher gains were observed for skin thickness, a trait affected by two genomic regions having particularly large effects. Higher accuracies than those from the original AM-BLUP were achieved when applying the Bayesian Sparse Linear Mixed Model to pre-select groups of SNPs with large effects and subsequently use their estimated variance to build a weighted GRM. Finally, the single-step GBLUP performed best and could be further improved (+ 3% prediction accuracy) by using these weighted GRM.ConclusionsThe AM-BLUP is an attractive method to automatically identify and weight genomic regions with large effects on complex traits. However, the method was less accurate than Bayesian methods. Overall, weighted methods achieved modest accuracy gains compared to GBLUP. Nevertheless, the computational efficiency of the AM-BLUP might be valuable at higher marker density, including with whole-genome sequencing data. Furthermore, weighted GRM are particularly useful to account for large variance loci in the single-step GBLUP.

Automation by Brain Sense Through Eeg Waves

Brain Computer Interface (BCI) is one of the communication channels used to make an interaction between human brain and digital computer to control/operate the external devices without having any touch of muscular body part. This provides the easiness in operations and also helpful to elder and decibel people. This is useful for people who cannot operate the peripheral devices using our normal muscular body parts. The proposed system aims to control home appliances (like bulb, fanatic.) with the help of Human Attention Level which come sunder on – invasive method of brains signal measurement. This attention is being measured by Neuro Sky Headset. Attention level values are ranges from 1 to 100. Attentionmeansuser’ level of mental focus which occurs during intense concentration and directed (but stable) mental activity. So, to get attention values user should observe the object (or focus on to the object). For demonstration purpose here are used one bulb and one fan.

Effects of Three Resistance Exercise Orders on Muscular Function and Body Composition in Older Women.

The purpose of the present study was to compare the effects of three resistance exercise orders on muscular strength, body composition, and functional fitness in trained older women. Forty-five women (aged ≥60 years), after performing 12 weeks of a pre-conditioning resistance-training program were randomly assigned in one of the following groups that performed the exercises in the following orders: multi-joint to single-joint order (MJ-SJ, n=15), single-joint to multi-joint order (SJ-MJ, n=15), and alternating between upper and lower body order (ALT, n=15). Specific training intervention lasted 12 weeks (3x/week) and was composed of eight exercises performed in three sets of 15/10/5 repetitions, with increasing load through the sets. Muscular strength was estimated by one-repetition maximum tests; body composition was assessed by whole-body dual-energy x-ray absorptiometry, and functional fitness was analyzed with a sequence of four motor tests. All groups improved similarly in muscular strength (Cohen's effect size: MJ-SJ=0.45; SJ-MJ=0.48; ALT=0.45), skeletal muscle mass (MJ-SJ=0.08; SJ-MJ=0.07; ALT=0.09), and functional test performance (MJ-SJ=0.38; SJ-MJ=0.20; ALT=0.31), but no change was observed for body fat (P>0.05). The results suggest that 12 weeks of resistance training induce positive changes in muscle morphofunctionality, regardless of the exercise order employed in trained older women.

Highly Sensitive Flexible Piezoresistive Sensor with 3D Conductive Network.

The flexible piezoresistive sensor has attracted more and more attention in health monitoring as a man-machine interface due to its simple structure and convenient signal reading. Herein, a highly sensitive flexible piezoresistive sensor with a 3D conductive sensing unit is presented. The 3D conductive sensing unit consists of a 3D network thermoplastic elastomer (TPE) substrate fabricated by fused deposition molding (FDM) 3D printing and carbon nanotubes (CNTs) conductive layer embedded into the surface of the TPE substrate. The finite element analysis (FEA) shows that the 3D network structure has excellent mechanical properties, which is basically consistent with the experimental results. Experimentally, based on the novel 3D conductive network, the flexible piezoresistive sensor exhibits superior comprehensive properties in the compressed or stretched state. The sensitivity of the sensor is as high as 136.8 kPa-1 at an applied pressure <200 Pa while compressing, and its gauge factor (GF) can reach 6.85 while stretching. Meanwhile, the sensor shows excellent stability and durability performance because CNTs embedded into the surface of the TPE substrate have little effect on the flexibility of the elastomeric composite of the sensor. Finally, the piezoresistive sensor is used for detecting subtle muscular movements (facial expressing and throat swallowing) and body movement like arm bending. These results indicate that the novel 3D conductive structure provides an alternative way to improve the performance of piezoresistive sensors and extend their potential applications in health monitoring.

The effects of an 8-week resistance training intervention on muscular strength, power, and body composition in collegiate female dancers

Although weight training can enhance muscular strength, power, and body composition, outdated beliefs about muscular adaptations have limited its use in dancers. The purpose of this study was to investigate the effect of an 8-week progressive overload resistance-training (RT) program on muscular strength, power and body composition in collegiate female dancers. Sixteen subjects were randomised into a dance-only control group (CON) or an RT + dance training group (EXP). EXP met 3×/week for RT. Body fat (%BF), lean body mass (LBM), girth measurements, vertical jump (VJ), muscular strength (1-repetition max (RM) squat (SQT) and 1-RM bench press (BP)), maximal oxygen consumption (V̇O2max, and ventilatory threshold (VT)) were assessed pre- and post-study. Baseline performance characteristics across all subjects were: %BF=28.2±5.7%, VJ=33.4±5.4 cm, SQT=57.5±12.1 kg, BP=30.1±7.6 kg, (V̇O2max)=40.6±3.4 ml/kg/min, and VT=71.2±3.4%VO2max. Strength improvements were significantly greater for EXP than CON (P&lt;0.05). No significant differences were found between groups for %BF, LBM, girth measurements, VJheight, (V̇O2max), or VT (P&gt;0.05). However, a trend was observed for VJpower favouring EXP (P=0.07). EXP significantly improved strength, while no significant changes were observed in body composition. However, EXP improved their power-to-weight ratio, which may be a positive performance adaptation. RT for dancers can improve strength and power, allowing enhanced muscular loading and fatigue-resistance, which may optimise performance and decrease injury risk.

Alterations In Musculoskeletal Function And Body Composition In Children With Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a neurological disorder characterized by impaired social interaction and atypical behaviors. Children with ASD appear to have weaker muscular function and low bone mineral density. Recent studies have indicated that adolescents with ASD develop obesity and bone fracture incidence at a higher rate compared to typically developing peers (TDC). Limited information is available to identify levels of obesity and its relation to muscular function and body composition in children with ASD before they start puberty. PURPOSE: To determine whether differential body composition may affect muscular strength and function in children with ASD METHODS: Total of 40 adults, TDC and children with ASD participated in the study. Muscular strength (i.e., torque, work, and power) during knee extension and flexion was measured at 90, 150, and 210 °/sec in the lower extremity using Humac Norm Isokinetic Dynamometer. Maximal isometric forearm muscular strength was measured using a handgrip dynamometer. Body mass index (BMI), waist-to-hip ratio, and whole-body scan from Dual Energy X-Ray Absorptiometry were used to identify the body composition. RESULTS: Compared to control adults, TDC and ASD had lower BMI (20.1±0.7 TDC, 22.3±4.4 ASD vs. 27.2±2.3 Adults, kg/m2). All groups had similar percent body fat (26.4± 2.3 Adults, 29.8±1.83 TDC, 32.9±3.84 ASD, %) and percent lean body mass (69.5±2.2 Adults, 66.8±1.7 TDC, 64.4±3.6 ASD, %). However, compared to TDC, ASD children had significantly lower bone mass percentage (2.7±0.3 ASD vs. 3.2±0.2 TDC, %). Waist-to-hip ratio was significantly higher for ASD (0.91±0.04 ASD vs. 0.85±0.01 TDC). The maximal forearm and leg strength were significantly lower in ASD compared to TDC normalized for their body weight (30.2 ±5.2 ASD vs. 42.8 ± 2.5 TDC, kg). There is a significant inverse relationship with muscular strength and regional percent fat in the forearm. CONCLUSION: These findings suggest that body composition appeared to influence muscular strength in children with ASD. Less regional fat and higher bone mass rather than the total body fat may contribute for higher leg or forearm muscular strength in children with ASD. Supported by CASA RSCA Infusion, Central RSCA, and Undergraduate Research Grant, SJSU

Creatine Creating Muscles or Creating Malady in Indian Youth: Medicolegal Issues

Most of Indian Urban Youth are keen of bulky bicep muscles, are getting misguided by online advertisements of “Creatine Creating Muscles”. Supplement abuse is rampant in the fitness world. Enthusiasts often take them without proper clearance from medical professionals and often feel the consequences later, in the end of the month. Relevant scientific studies warns the Harmful Effects on kidneys of even healthy youth, associated with consuming creatine supplement for creating muscular body building a long with physical workouts by weight lifting in Gymnasiums. The doctors get baffled to see otherwise healthy, young males hospitalized for an avoidable emergency, by regulating creatine use only after medical expert’s supervision and monitoring.

P0960HOME BASED RESISTANCE EXERCISE PROGRAM AND SARCOPENIA IN HEMODIALYSIS PATIENTS: IT IS A USEFUL INTERVENTION?

Abstract Background and Aims Sarcopenia is a skeletal muscle disorder associated with adverse outcomes including falls, physical disability and mortality particularly in hemodialysis (HD) patients. Currently, progressive resistance training exercise has been shown a proven method to treat and prevent sarcopenia. Nevertheless, these findings are poorly investigated in HD patients since exercise programs are not widespread. The aim of our study was to assess the effect of a home-based resistance exercise program (HBREP) on muscular strength, functional capacity and body composition in our hemodialysis patients with sarcopenia according to the European Working Group on Sarcopenia in Older People criteria (EWGSOP2). Method A 12 weeks single-center prospective study. HD patients from our institution with EWGSOP2 sarcopenia diagnosis were enrolled in a HBREP. Demographical an anthropometrical data, main biochemical and nutritional parameters, hand grip (HG) muscular strength, functional capacity tests: Sit to stand to seat 5 (STS5); Short Physical Performance Battery (SPPB), gait speed (GS), as well as body composition determined by electrical bioimpedance (BIA) and sarcopenia severity were analized. Results 18 HD patients with sarcopenia (71.4% severe) were included (4 drop out).78.6% men. Mean age 74.7 years and 53.3 months on HD. The main etiologies of ESRD were the HBP (21.4%) and DM (14.3%). Globally, a significant improvement was observed at the end of the study in relation to muscular strength (HG 19.9±6.1 vs 22.2±7.1 kg, p 0.001) and functional capacity tests (STS5 21.9±10.3 vs 17.2±9.9 sec, p 0.001; SPPB (6.9±2.3 vs 9.1±2.5 score, p 0.001 and GS 0.8±0.1 vs 0.9±0.2 m/s, p 0.015). Likewise, higher total skeletal muscle mass (SMM, 14.3±2.8 vs 14.5±2.9 kg) and SMM index (SMM/height2, 5.5±0.7 vs 5.7±0.9 Kg/m2 ) were found at the end of the study, although these differences were not significant. Finally, 2 patients (14.8%) reverse the EWGSOP2 sarcopenia criteria and 3 (21.4%) enhanced their severe sarcopenia. No relevant changes regarding anthropometrical data, main biochemical and nutritional parameters or dialysis adequacy were observed at the end of the study. Conclusion A home-based resistance exercise program improves muscular strength, functional capacity and body composition in our sarcopenic hemodialysis patients. With our results, home-based resistance exercise programs should be considered a key point in the prevention and treatment of skeletal muscle mass reduction due to sarcopenia in these patients. Further studies are mandatory to confirm our encouraging results.

Somatotype of Santal Tribal Women of West Bengal in India

Sixty-four Santal tribal women from Paschim Medinipur district, West Bengal, India, were studied for their somatotype. The studied women were with an average age of 32.5 ± 11.6 years with a wide age range of 16–70. Average height was 150.2 (±5.2) cm. Heath–Carter method (1967) was followed for somatotyping. Average somatotype of the studied Santal women was 3.9 (±1.5) – 4.1 (1.1) – 2.9 ± (1.7). A total of 16–20 year age group had an average somatotype of 3.7 (±1.0) – 3.3 (±0.7) – 3.4 (±1.5), whereas that of 21–30 had an average somatotype of 3.4 (±1.2) – 3.7 (±1.0) – 3.9 (±1.5). A total of 31–40 year age group were more mesomorphic with an average somatotype of 4.4 (±1.6) – 4.4 (±1.2) – 2.1 (±1.7). Mesomorphy component increased as the Santal women grew up. The women from age group 41 to 50 year had an average somatotype of 4.0 (±1.6) – 4.6 (±1.1) – 1.9 (±1.3), whereas that of older women of 51–70 year age group were more mesomorphic with an average value of 5.0 (±1.9) – 5.1 (±0.7) – 1.7 (±0.7). Thus, muscularity of the Santal women increased as age increased. This was due to their changed lifestyle from young age to older age where older had to do more physical work than the young adults. Thus, well-built muscular body type of Santal women was an adaptation for hard physical work for survival.

Abdominal musculature segmentation and surface prediction from CT using deep learning for sarcopenia assessment

PurposeThe purpose of this study was to build and train a deep convolutional neural networks (CNN) algorithm to segment muscular body mass (MBM) to predict muscular surface from a two-dimensional axial computed tomography (CT) slice through L3 vertebra. Materials and methodsAn ensemble of 15 deep learning models with a two-dimensional U-net architecture with a 4-level depth and 18 initial filters were trained to segment MBM. The muscular surface values were computed from the predicted masks and corrected with the algorithm's estimated bias. Resulting mask prediction and surface prediction were assessed using Dice similarity coefficient (DSC) and root mean squared error (RMSE) scores respectively using ground truth masks as standards of reference. ResultsA total of 1025 individual CT slices were used for training and validation and 500 additional axial CT slices were used for testing. The obtained mean DSC and RMSE on the test set were 0.97 and 3.7 cm2 respectively. ConclusionDeep learning methods using convolutional neural networks algorithm enable a robust and automated extraction of CT derived MBM for sarcopenia assessment, which could be implemented in a clinical workflow.

Effect of Resistance Training Under Normobaric Hypoxia on Physical Performance, Hematological Parameters, and Body Composition in Young and Older People

BackgroundResistance training (RT) under hypoxic conditions has been used to increase muscular performance under normoxic conditions in young people. However, the effects of RT and thus of RT under hypoxia (RTH) could also be valuable for parameters of physical capacity and body composition across the lifespan. Therefore, we compared the effects of low- to moderate-load RTH with matched designed RT on muscular strength capacity, cardiopulmonary capacity, hematological adaptation, and body composition in young and older people.MethodsIn a pre–post randomized, blinded, and controlled experiment, 42 young (18 to 30 year) and 42 older (60 to 75 year) participants were randomly assigned to RTH or RT (RTH young, RT young, RTH old, RT old). Both groups performed eight resistance exercises (25–40% of 1RM, 3 × 15 repetitions) four times a week over 5 weeks. The intensity of hypoxic air for the RTH was administered individually in regards to the oxygen saturation of the blood (SpO2): ∼80–85%. Changes and differences in maximal isokinetic strength, cardiopulmonary capacity, total hemoglobin mass (tHb), blood volume (BV), fat free mass (FFM), and fat mass (FM) were determined pre–post, and the acute reaction of erythropoietin (EPO) was tested during the intervention.ResultsIn all parameters, no significant pre–post differences in mean changes (time × group effects p = 0.120 to 1.000) were found between RTH and RT within the age groups. However, within the four groups, isolated significant improvements (p < 0.050) of the single groups were observed regarding the muscular strength of the legs and the cardiopulmonary capacity.DiscussionAlthough the hypoxic dose and the exercise variables of the resistance training in this study were based on the current recommendations of RTH, the RTH design used had no superior effect on the tested parameters in young and older people in comparison to the matched designed RT under normoxia after a 5-week intervention period. Based on previous RTH-studies as well as the knowledge about RT in general, it can be assumed that the expected higher effects of RTH can may be achieved by changing exercise variables (e.g., longer intervention period, higher loads).

Male Body Image Portrayals on Instagram.

Men are faced with trends that give rise to the desire for a muscular and lean body; this may result in body dissatisfaction. Body dissatisfaction is associated with a plethora of health consequences. Social media has been named as one contributing factor for male body dissatisfaction. Up till now, women have been the focus of body image-related social media studies. Therefore, we conducted a quantitative content analysis of 1,000 relevant Instagram posts that were posted by men (and/or depicted men) to understand how the male body is depicted on Instagram and how user respond to those images. The majority of sampled posts showed high levels of muscularity and leanness. In addition, posts depicting men adhering to this specific body type received significantly more responses (likes and comments). Norms and outcomes related to health (i.e., training to be healthy) were more commonly shown than appearance-related constructs (i.e., training to become attractive), and promotion of physical activity was more common than dietary behavior. However, findings are potential harmful to men's body image, even if one considers that health-related messaging and physical active promotion was prominent. It remains debatable if men need to view very lean and very muscular men to encourage health-related behaviors.

Muscles and the Media: A Natural Experiment Across Cultures in Men's Body Image.

An increasing number of studies are evidencing relationships between the drive for muscularity and potentially harmful behavioral strategies, such as unhealthy dieting and steroid use amongst men in WEIRD (Western, Educated, Industrialized, Rich, Democratic) populations. As such Western appearance standards proliferate around the world via the media, men who live in other cultural contexts are also at risk of potentially negative effects from aspiring to the “muscular ideal.” However, few studies have explored these relationships in non-WEIRD populations. We investigated men’s body ideals and body image in two non-WEIRD, non-White populations, Uganda (Africa) and Nicaragua (Central America), and compared them with an ethnically diverse sample of men in the United Kingdom. We also examined whether socio-cultural factors including media and ethnicity, predicted the drive for muscularity and body change behaviors among our participants. Results showed that Ugandan men had the least desire for muscularity relative to men in the United Kingdom. Supporting the Tripartite model we found that media and peer influences significantly predicted the drive for muscularity, particularly among men from White British and Nicaraguan Miskitu ethnic groups. By contrast, Creole / Garifuna and Mestizo men from Nicaragua were more likely to want to increase muscularity relative to Black African men from Uganda. Overall, our findings support previous research in demonstrating that there are cultural differences in the kind of body men desire, and that men from WEIRD and non-WEIRD populations may experience similar pressures to aspire to and attain a muscular body type.

Effects of Selective Breeding for Voluntary Exercise, Chronic Exercise, and Their Interaction on Muscle Attachment Site Morphology in House Mice

Skeletal muscles attach to bone at their origins and insertions, and the interface where tendon meets bone is termed the muscle attachment site (or enthesis). Muscle attachment sites function to anchor muscles/tendons to bone and to dissipate stress (force per unit area) resulting from force transmission. Mechanical stresses at the muscle/tendon‐bone interface are proportional to surface area of the bony attachment sites, so a larger muscle attachment site will distribute loads over a wider surface area. Muscles that are frequently active and/or are of larger size should cause muscle attachment sites to hypertrophy (training effect), so paleontological studies have often used characteristics of attachment sites as indicators of locomotor behavior.In studies of humans, muscle attachment sites have been used to infer physical activity of fossil specimens, with larger attachment sites assumed to indicate larger muscles and/or habitual use. For example, muscle attachment site morphology was examined in prehistoric Andean fishing and agricultural populations. From this data, anthropologists concluded that the fishing population had more muscular upper bodies while the agricultural population had more muscular lower bodies. Such differences in muscle attachment site morphology have been attributed to differences in physical activity levels and loading history of limb bones experienced by individuals during their lifetime. However, bone performance during loading is governed by both genetic factors and loading history, but also by age, sex, and epigenetic factors. Thus, controversy arises when paleontologists attempt to infer the past loading history (i.e., activity levels) of individuals from bone morphology.We studied 4 replicate lines of high runner (HR) mice that had been selectively bred for 57 generations based on the average number of wheel revolutions on days 5 &amp; 6 of a 6‐day period of wheel access. Four additional lines have been bred without regard to wheel running and serve as controls (C). On average, mice from HR lines voluntarily run ~3 times more than C mice on a daily basis. We housed 100 mice with or without wheels for 12 weeks starting at weaning. We quantified the evolved differences in muscle attachment site morphology between HR and C mice as well as plastic changes resulting from chronic exposure to exercise by measuring the cortical cross‐sectional areas, linear dimensions, and total surface area for muscles that attach on the femur and humerus. Sites chosen for subsequent analysis included the femoral third trochanter, an insertion point for the quadratus femoris, and the humerus deltoid crest, an insertion point for the spinodeltoideus, superficial pectoralis, and acromiodeltoideus.With body mass as a covariate, HR mice had significantly larger humerus deltoid tuberosities than C, with no significant training effect. Morphology of the femoral third trochanter did not differ between HR and C mice and was unaffected by chronic wheel access. Our results suggest that muscle attachment site morphology is largely determined by genetic background rather than exercise during ontogeny.3D Model of the Femoral Third Trochanter of a MouseFigure 1