Better Abs, Better Sex?
Do You Have the Stomach for Bedroom Activity?
As crude as it may sound in today’s world of global overpopulation and long-delayed frank discussions about abusive behavior toward women by misogynist cultures and individuals (e.g., college campus sexual assaults, sexual torture and slavery by religious extremists, etc.), the pursuit of sexual reward is a powerful motivator down to the most base part of the brain. Need proof? Just look at the role of “sex” in advertising.1 Thankfully, humans are capable of applying reason when choosing to engage in sexual behavior, and have resources to allow for the enjoyment of recreational sex when properly using methods to reduce the odds of conception (i.e., pregnancy). Cultures that prohibit the use of “birth control” or do not protect a woman’s rights and safety are outside the scope of this discussion.
In Search of a Six-Pack
In regard to physical attraction, potential mates consciously or subconsciously evaluate the fitness, health and sexual potential of their prospective partner. Discounting the equally (or greater) important aspects of attraction that depend upon character, personality, humor, stability, social and psychological compatibility, etc., a person with a lean and athletic core provides a positive stimulus in regard to sexuality. Certain cultures deviate to more “Rubenesque” women (plump in a pleasing or attractive manner), who are desirable as they are believed to represent greater fertility and capability to deliver healthy newborns. Perhaps more importantly, those who see themselves as highly selective are likely to look for, and pursue as a goal for him/herself, a person with similar features.2 In other words, if you are attracted to a physically fit woman, she is likely seeking a physically fit man. With rare exception, “opposites attract” is little more than a myth.
For the man, there is a functional purpose supporting the presentation of a solid, well-developed core in regard to his ability to perform sexually, both for his pleasure and his partner. Certainly, the implication of good health, fitness, ability to adhere to the discipline of exercise and a sound diet, and avoid the metabolic problems associated with abdominal obesity, are fundamentals that tend to give a man with prominent abdominal muscles an advantage over his abdominally flaccid or obese competitor. However, there is also the “eye candy” effect. For sheerly hedonic pleasure-seeking women, nothing grabs the eyes like a set of washboard abs and a nice set of buns. These two features regularly grab the top spots on body parts women focus on when judging a man’s level of attractiveness.
So, insofar as attracting a partner— for many, the greatest barrier to a fulfilling sex life— it is apparently key to drop the body fat down to where the abdominal muscles are apparent and the musculature of the buttocks are sculpted. The key steps, of course, are to manage the diet so that body fat is maintained in the upper single digits, and incorporate an exercise routine that creates tone, definition and aesthetic hypertrophy (muscle size) to attract the desired level of attention. Once the “look” has been achieved, is there any further value to having a “six-pack” of abs, strong spinal erectors and the butt of a thoroughbred stallion? Interestingly, form does dictate function to some degree. A solid and sexy core offers the promise of optimal sexual function. Never forget, though, that sexual interaction is only part of a relationship. If you are not capable of developing and maintaining a healthy relationship, you will only be experiencing the transient physical pleasure. Many of the greatest rewards of a sexual relationship are experienced when it supports a thriving relationship; not just satisfying your momentary urges with no regard for your partner. Some of the gravest risks come from indiscriminate promiscuity— or hooking up with pretty much anyone.
50 Shades of Lust
The physical act of intercourse was for a time fairly uniform, and globally understood. Most major religions utilized the physical representation of intercourse to affirm the role between man and woman, with the man in the dominant position. Puritanical influences in British and early American history assigned shame and guilt to LUST— one of the seven deadly sins. Thus the “missionary position” nomenclature, which was referred to by Shakespeare as the “beast with two backs.” This was not always so. The Talmud and many other sources refer to Lilith (apparently the first women, created alongside Adam) as a sexually voracious woman who would defile men with her sexual dominance. She left, or was cast out of, the Garden of Eden for refusing to “lie beneath Adam,” a reference often interpreted as relating to the “missionary position.”
Author EL James brought sexual exploration into the spotlight with the success of the 50 Shades of Grey trilogy. Again, a story revisited instead of being creative or innovative. Sexual exploration exists in some of the most ancient texts, such as the Kama Sutra or the writings of the Marquis de Sade, and it continues in pulp fiction today. Clearly, the need for a strong core is a necessity if exploring some of the more acrobatic positions.
Getting down to the “meat of the matter,” sexual intercourse involves: being able to develop desire and arousal (mental health); intact erectile function (circulatory and endocrine health); physical strength, endurance and flexibility to perform sexually (musculoskeletal and cardiovascular health); ejaculation (sexual function) and post-coital bonding (relationship and social health).
A six-pack, ripped abs or V-taper— however you want to refer to the “look”— is a sign that all systems should be “go.” Let’s call the “look” ripped abs, just for simplicity sake. Though most people of all shapes and sizes are mentally healthy, maintaining a healthy and aesthetic physique is often a reliable sign of a mature and stable personality, as well as a balanced lifestyle in adults. Of course, many young people benefit from their age in being able to develop abs through their youthful metabolism and the physical nature of much of their recreation (dance, sports, etc.). Also, there are a number of people who are fixated upon their appearance to the point of having a personality disorder or frank psychosis.3 Yet, compare the psyche of a fit person who is satisfied with his body image to one who is dissatisfied with being obese, or to the psyche of someone who is normal weight but lacking muscular development due to a sedentary job or lifestyle, or even to the psyche of someone who is fit but has a negative self-perception. These negative emotions can be amplified by interaction when seeking approval or acceptance. A negative self-image can also cause insecurities in a relationship, leading to unhealthy distrust, jealousy or a constant need for reinforcement.4
So, though it seems superficial, being in shape can support a healthy mental state by preventing dissatisfaction relating to a negative self-image, reduce concern about competitive males, express a stable mood and enable a trusting relationship. Abs, in and of themselves, are not a sure thing in regard to mental health. In some cases, it can be an indication of narcissism, obsession, eating disorders, drug abuse or just being a “diva.”5,6 However, all else being equal, a nice taper and set of abs can promote mental health and boost confidence in receiving others' approval and acceptance.
Good Health, Great Abs and Better Sex
You just can't develop a great set of abs without being physically active and consuming a nutritious diet (most of the time). Avoiding abdominal obesity greatly reduces the risk of metabolic syndrome, and physical activity helps promote insulin sensitivity.7,8 The metabolic syndrome includes hypertension, high cholesterol, abdominal obesity, insulin resistance and other maladies. By avoiding the onset of metabolic syndrome— thought by many to be preceded by insulin resistance and obesity-related inflammation— vascular functions are well maintained. It should be noted that certain conditions affecting vascular health are inherited.
The most evident vascular function for men is obtaining and maintaining an erection. Erectile dysfunction has several different causes, but the most prevalent is small-vessel disease (the smaller arteries that supply blood to tissue, including the penis).9 Viagra-like drugs work by prolonging the dilation (opening) of those small vessels, supporting the blood flow necessary to “get it up.” A well-developed and ripped midsection and a fit core strongly suggest that the conditions leading to vasculogenic erectile dysfunction are NOT present. Also, as visibly apparent abs are some of the “last to appear” and “first to go” muscles, it is a sign that your follow a lifestyle that is not likely to dissipate. For the doubters, a study published in 2012 reported exercise in men under 40 is associated with better erectile function.10
Beyond that, abs may indicate that you have an endocrine system that is in balance, with a strong testosterone presence. The muscular development notable in the core, and hopefully with full-body symmetry, indicates that testosterone activity is fully expressed. Certainly, erectile function is dependent upon testosterone’s actions (as well as its metabolites). However, this occurs at a concentration that is well below what is necessary for bone and muscle mass maintenance.11,12 Showing that you can develop muscle, have a waist circumference that provides a V-taper and are comfortable with your physical image … the sum total is pretty much a visual guarantee that you are capable of performing sexually.
OK, you attract your partner who anticipates that you have the goods. Mission accomplished? No, of course not— there is still the main event. Sexual intercourse, which of course depends upon desire, comfort, foreplay and a multitude of other underappreciated factors, is a physically strenuous act or series of acts. In fact, sexual intercourse is recognized as an important risk factor for a heart attack.13 So, spend a little time on the treadmill, men, if you want to survive heated moments of passion. Sex does burn calories, but the effect is less than other forms of exercise, like riding a bike.14 So, enjoying sex frequently might have a limited conditioning effect, but it would need to be discussed with your physician first, just like any diet or exercise program.
Are You Ready to Rumble?
Most sexual positions and motions involve pelvic motion of variable but considerable force and frequency. For the more vigorous, a man may be supporting some or all of his bodyweight; possibly that of his partner as well. Frankly, the frightening possibility of a sex-gym franchise is not outside the realm of marketing creativity. However, it is more important for immediate needs of the partners involved that muscular strength is already present in the abdominal, pelvic and gluteal muscles. Developing the abs for looks will provide the cross-benefit of increasing the strength of these muscles as well. If your partner is attracted to a fit physique, this will provide visual, tactile and functional sensation during an event of heightened desire and arousal. A woman experiences more frequent and intense orgasms if she views her partner as attractive— more so if her friends find her partner attractive.15 Self-confidence (improved with a positive self-image in the male) and financial wealth also play a factor. Sadly, doing crunches and leg lifts are not a proven road to becoming independently wealthy.
The importance of core strength and integrity in sex can be seen when it is absent (e.g., back injury) or by appreciating the dynamics of the repeated thrusting that characterizes penile-vaginal intercourse, and other variations. Men who suffer from chronic lower back pain, which can be prevented or reduced with core strengthening, suffer twice as many complaints of sexual dysfunction— including erectile dysfunction, loss of libido and painful intercourse positions.16,17 In observance of the risk of back pain, a study compared three sexual positions for spine motion. All three depended upon spinal flexion (abdominal strength), as opposed to extension (lumbar erectors). Quadruped (doggy-style) involved the most rapid movement, with side-lying being the slowest; missionary style was the third position. Interestingly, the most “back-friendly” for the man is doggy-style, with the woman supporting her weight on her elbows.18 For the woman, the same position but raised to rest her weight on her hands is most comfortable.19 Again, only three positions were noted, with variations— and the goal was to seek back comfort, not sexual stimulation.
A well-defined core, in a mentally healthy man, is a sign of sexual function and potential prowess when viewed by prospective partners. Great abs demonstrate an adherence to a healthy lifestyle, physical attractiveness, metabolic health, vascular function, hormonal (testosterone) sufficiency, strength and structural integrity— strong indicators that proclaim to an interested party that you are capable of providing a satisfying sexual relationship.
Hard to imagine a more motivating reason to work the core.
DISCUSS THIS ARTICLE ON THE MD FORUM
READ MORE ARTICLES LIKE THIS IN THE SEX SECTION
References:
1. Reichert T. Sex in advertising research: a review of content, effects, and functions of sexual information in consumer advertising. Annu Rev Sex Res 2002;13:241-73.
2. Buston PM, Emlen ST. Cognitive processes underlying human mate choice: The relationship between self-perception and mate preference in Western society. Proc Natl Acad Sci USA 2003;100:8805-10.
3. Homan KJ, Tylka TL. Appearance-based exercise motivation moderates the relationship between exercise frequency and positive body image. Body Image 2014;11:101-8.
4. Mitchell KR, Orr FE. Heterosexual social competence, anxiety, avoidance and self-judged physical attractiveness. Percept Mot Skills 1976;42:553-4.
5. Bruno A, Quattrone D, et al. Unraveling exercise addiction: the role of narcissism and self-esteem. J Addict 2014;2014:987841(6 pp). doi: 10.1155/2014/987841.
6. Nieuwoudt JE, Zhou S, et al. Symptoms of muscle dysmorphia, body dysmorphic disorder, and eating disorders in a nonclinical population of adult male weightlifters in Australia. J Strength Cond Res 2015;29:1406-14.
7. Phillips LK, Prins JB. The link between abdominal obesity and the metabolic syndrome. Curr Hypertens Rep 2008;10:156-64.
8. Khoo J, Dhamodaran S, et al. Exercise-Induced Weight Loss is More Effective Than Dieting for Improving Adipokine Profile, Insulin Resistance and Inflammation in Obese Men. Int J Sport Nutr Exerc Metab 2015 May 22. [Epub, ahead of print]
9. Ludwig W, Phillips M. Organic Causes of erectile dysfunction in men under 40. Urol Int 2014;92:1-6.
10. Hsiao W, Shrewsberry AB, et al. Exercise is associated with better erectile function in men under 40 as evaluated by the International Index of Erectile Function. J Sex Med 2012;9:524-30.
11. Mikhail N. Does testosterone have a role in erectile function? Am J Med 2006;119:373-82.
12. Sattler F, Bhasin S, et al. Testosterone threshold levels and lean tissue mass targets needed to enhance skeletal muscle strength and function: the HORMA trial. J Gerontol A Biol Sci Med Sci 2011;66:122-9.
13. Culić V. Acute risk factors for myocardial infarction. Int J Cardiol 2007;117:260-9.
14. Chen X1, Zhang Q, et al. Cardiovascular effects of sexual activity. Indian J Med Res 2009;130:681-8.
15. Gallup GG Jr, Ampel BC, et al. Do orgasms give women feedback about mate choice? Evol Psychol 2014;12:958-78.
16. Nikoobakht M, Fraidouni N, et al. Sexual function and associated factors in Iranian patients with chronic low back pain. Spinal Cord 2014;52:307-12.
17. Bahouq H, Fadoua A, et al. Profile of sexuality in Moroccan chronic low back pain patients. BMC Musculoskelet Disord 2013;14:63-8.
18. Sidorkewicz N, McGill SM. Male spine motion during coitus: implications for the low back pain patient. Spine 2014;39:1633-9.
19. Sidorkewicz N, McGill SM. Documenting female spine motion during coitus with a commentary on the implications for the low back pain patient. Eur Spine J 2015;24:513-20
Do You Have the Stomach for Bedroom Activity?
As crude as it may sound in today’s world of global overpopulation and long-delayed frank discussions about abusive behavior toward women by misogynist cultures and individuals (e.g., college campus sexual assaults, sexual torture and slavery by religious extremists, etc.), the pursuit of sexual reward is a powerful motivator down to the most base part of the brain. Need proof? Just look at the role of “sex” in advertising.1 Thankfully, humans are capable of applying reason when choosing to engage in sexual behavior, and have resources to allow for the enjoyment of recreational sex when properly using methods to reduce the odds of conception (i.e., pregnancy). Cultures that prohibit the use of “birth control” or do not protect a woman’s rights and safety are outside the scope of this discussion.
In Search of a Six-Pack
In regard to physical attraction, potential mates consciously or subconsciously evaluate the fitness, health and sexual potential of their prospective partner. Discounting the equally (or greater) important aspects of attraction that depend upon character, personality, humor, stability, social and psychological compatibility, etc., a person with a lean and athletic core provides a positive stimulus in regard to sexuality. Certain cultures deviate to more “Rubenesque” women (plump in a pleasing or attractive manner), who are desirable as they are believed to represent greater fertility and capability to deliver healthy newborns. Perhaps more importantly, those who see themselves as highly selective are likely to look for, and pursue as a goal for him/herself, a person with similar features.2 In other words, if you are attracted to a physically fit woman, she is likely seeking a physically fit man. With rare exception, “opposites attract” is little more than a myth.
For the man, there is a functional purpose supporting the presentation of a solid, well-developed core in regard to his ability to perform sexually, both for his pleasure and his partner. Certainly, the implication of good health, fitness, ability to adhere to the discipline of exercise and a sound diet, and avoid the metabolic problems associated with abdominal obesity, are fundamentals that tend to give a man with prominent abdominal muscles an advantage over his abdominally flaccid or obese competitor. However, there is also the “eye candy” effect. For sheerly hedonic pleasure-seeking women, nothing grabs the eyes like a set of washboard abs and a nice set of buns. These two features regularly grab the top spots on body parts women focus on when judging a man’s level of attractiveness.
So, insofar as attracting a partner— for many, the greatest barrier to a fulfilling sex life— it is apparently key to drop the body fat down to where the abdominal muscles are apparent and the musculature of the buttocks are sculpted. The key steps, of course, are to manage the diet so that body fat is maintained in the upper single digits, and incorporate an exercise routine that creates tone, definition and aesthetic hypertrophy (muscle size) to attract the desired level of attention. Once the “look” has been achieved, is there any further value to having a “six-pack” of abs, strong spinal erectors and the butt of a thoroughbred stallion? Interestingly, form does dictate function to some degree. A solid and sexy core offers the promise of optimal sexual function. Never forget, though, that sexual interaction is only part of a relationship. If you are not capable of developing and maintaining a healthy relationship, you will only be experiencing the transient physical pleasure. Many of the greatest rewards of a sexual relationship are experienced when it supports a thriving relationship; not just satisfying your momentary urges with no regard for your partner. Some of the gravest risks come from indiscriminate promiscuity— or hooking up with pretty much anyone.
50 Shades of Lust
The physical act of intercourse was for a time fairly uniform, and globally understood. Most major religions utilized the physical representation of intercourse to affirm the role between man and woman, with the man in the dominant position. Puritanical influences in British and early American history assigned shame and guilt to LUST— one of the seven deadly sins. Thus the “missionary position” nomenclature, which was referred to by Shakespeare as the “beast with two backs.” This was not always so. The Talmud and many other sources refer to Lilith (apparently the first women, created alongside Adam) as a sexually voracious woman who would defile men with her sexual dominance. She left, or was cast out of, the Garden of Eden for refusing to “lie beneath Adam,” a reference often interpreted as relating to the “missionary position.”
Author EL James brought sexual exploration into the spotlight with the success of the 50 Shades of Grey trilogy. Again, a story revisited instead of being creative or innovative. Sexual exploration exists in some of the most ancient texts, such as the Kama Sutra or the writings of the Marquis de Sade, and it continues in pulp fiction today. Clearly, the need for a strong core is a necessity if exploring some of the more acrobatic positions.
Getting down to the “meat of the matter,” sexual intercourse involves: being able to develop desire and arousal (mental health); intact erectile function (circulatory and endocrine health); physical strength, endurance and flexibility to perform sexually (musculoskeletal and cardiovascular health); ejaculation (sexual function) and post-coital bonding (relationship and social health).
A six-pack, ripped abs or V-taper— however you want to refer to the “look”— is a sign that all systems should be “go.” Let’s call the “look” ripped abs, just for simplicity sake. Though most people of all shapes and sizes are mentally healthy, maintaining a healthy and aesthetic physique is often a reliable sign of a mature and stable personality, as well as a balanced lifestyle in adults. Of course, many young people benefit from their age in being able to develop abs through their youthful metabolism and the physical nature of much of their recreation (dance, sports, etc.). Also, there are a number of people who are fixated upon their appearance to the point of having a personality disorder or frank psychosis.3 Yet, compare the psyche of a fit person who is satisfied with his body image to one who is dissatisfied with being obese, or to the psyche of someone who is normal weight but lacking muscular development due to a sedentary job or lifestyle, or even to the psyche of someone who is fit but has a negative self-perception. These negative emotions can be amplified by interaction when seeking approval or acceptance. A negative self-image can also cause insecurities in a relationship, leading to unhealthy distrust, jealousy or a constant need for reinforcement.4
So, though it seems superficial, being in shape can support a healthy mental state by preventing dissatisfaction relating to a negative self-image, reduce concern about competitive males, express a stable mood and enable a trusting relationship. Abs, in and of themselves, are not a sure thing in regard to mental health. In some cases, it can be an indication of narcissism, obsession, eating disorders, drug abuse or just being a “diva.”5,6 However, all else being equal, a nice taper and set of abs can promote mental health and boost confidence in receiving others' approval and acceptance.
Good Health, Great Abs and Better Sex
You just can't develop a great set of abs without being physically active and consuming a nutritious diet (most of the time). Avoiding abdominal obesity greatly reduces the risk of metabolic syndrome, and physical activity helps promote insulin sensitivity.7,8 The metabolic syndrome includes hypertension, high cholesterol, abdominal obesity, insulin resistance and other maladies. By avoiding the onset of metabolic syndrome— thought by many to be preceded by insulin resistance and obesity-related inflammation— vascular functions are well maintained. It should be noted that certain conditions affecting vascular health are inherited.
The most evident vascular function for men is obtaining and maintaining an erection. Erectile dysfunction has several different causes, but the most prevalent is small-vessel disease (the smaller arteries that supply blood to tissue, including the penis).9 Viagra-like drugs work by prolonging the dilation (opening) of those small vessels, supporting the blood flow necessary to “get it up.” A well-developed and ripped midsection and a fit core strongly suggest that the conditions leading to vasculogenic erectile dysfunction are NOT present. Also, as visibly apparent abs are some of the “last to appear” and “first to go” muscles, it is a sign that your follow a lifestyle that is not likely to dissipate. For the doubters, a study published in 2012 reported exercise in men under 40 is associated with better erectile function.10
Beyond that, abs may indicate that you have an endocrine system that is in balance, with a strong testosterone presence. The muscular development notable in the core, and hopefully with full-body symmetry, indicates that testosterone activity is fully expressed. Certainly, erectile function is dependent upon testosterone’s actions (as well as its metabolites). However, this occurs at a concentration that is well below what is necessary for bone and muscle mass maintenance.11,12 Showing that you can develop muscle, have a waist circumference that provides a V-taper and are comfortable with your physical image … the sum total is pretty much a visual guarantee that you are capable of performing sexually.
OK, you attract your partner who anticipates that you have the goods. Mission accomplished? No, of course not— there is still the main event. Sexual intercourse, which of course depends upon desire, comfort, foreplay and a multitude of other underappreciated factors, is a physically strenuous act or series of acts. In fact, sexual intercourse is recognized as an important risk factor for a heart attack.13 So, spend a little time on the treadmill, men, if you want to survive heated moments of passion. Sex does burn calories, but the effect is less than other forms of exercise, like riding a bike.14 So, enjoying sex frequently might have a limited conditioning effect, but it would need to be discussed with your physician first, just like any diet or exercise program.
Are You Ready to Rumble?
Most sexual positions and motions involve pelvic motion of variable but considerable force and frequency. For the more vigorous, a man may be supporting some or all of his bodyweight; possibly that of his partner as well. Frankly, the frightening possibility of a sex-gym franchise is not outside the realm of marketing creativity. However, it is more important for immediate needs of the partners involved that muscular strength is already present in the abdominal, pelvic and gluteal muscles. Developing the abs for looks will provide the cross-benefit of increasing the strength of these muscles as well. If your partner is attracted to a fit physique, this will provide visual, tactile and functional sensation during an event of heightened desire and arousal. A woman experiences more frequent and intense orgasms if she views her partner as attractive— more so if her friends find her partner attractive.15 Self-confidence (improved with a positive self-image in the male) and financial wealth also play a factor. Sadly, doing crunches and leg lifts are not a proven road to becoming independently wealthy.
The importance of core strength and integrity in sex can be seen when it is absent (e.g., back injury) or by appreciating the dynamics of the repeated thrusting that characterizes penile-vaginal intercourse, and other variations. Men who suffer from chronic lower back pain, which can be prevented or reduced with core strengthening, suffer twice as many complaints of sexual dysfunction— including erectile dysfunction, loss of libido and painful intercourse positions.16,17 In observance of the risk of back pain, a study compared three sexual positions for spine motion. All three depended upon spinal flexion (abdominal strength), as opposed to extension (lumbar erectors). Quadruped (doggy-style) involved the most rapid movement, with side-lying being the slowest; missionary style was the third position. Interestingly, the most “back-friendly” for the man is doggy-style, with the woman supporting her weight on her elbows.18 For the woman, the same position but raised to rest her weight on her hands is most comfortable.19 Again, only three positions were noted, with variations— and the goal was to seek back comfort, not sexual stimulation.
A well-defined core, in a mentally healthy man, is a sign of sexual function and potential prowess when viewed by prospective partners. Great abs demonstrate an adherence to a healthy lifestyle, physical attractiveness, metabolic health, vascular function, hormonal (testosterone) sufficiency, strength and structural integrity— strong indicators that proclaim to an interested party that you are capable of providing a satisfying sexual relationship.
Hard to imagine a more motivating reason to work the core.
DISCUSS THIS ARTICLE ON THE MD FORUM
READ MORE ARTICLES LIKE THIS IN THE SEX SECTION
References:
1. Reichert T. Sex in advertising research: a review of content, effects, and functions of sexual information in consumer advertising. Annu Rev Sex Res 2002;13:241-73.
2. Buston PM, Emlen ST. Cognitive processes underlying human mate choice: The relationship between self-perception and mate preference in Western society. Proc Natl Acad Sci USA 2003;100:8805-10.
3. Homan KJ, Tylka TL. Appearance-based exercise motivation moderates the relationship between exercise frequency and positive body image. Body Image 2014;11:101-8.
4. Mitchell KR, Orr FE. Heterosexual social competence, anxiety, avoidance and self-judged physical attractiveness. Percept Mot Skills 1976;42:553-4.
5. Bruno A, Quattrone D, et al. Unraveling exercise addiction: the role of narcissism and self-esteem. J Addict 2014;2014:987841(6 pp). doi: 10.1155/2014/987841.
6. Nieuwoudt JE, Zhou S, et al. Symptoms of muscle dysmorphia, body dysmorphic disorder, and eating disorders in a nonclinical population of adult male weightlifters in Australia. J Strength Cond Res 2015;29:1406-14.
7. Phillips LK, Prins JB. The link between abdominal obesity and the metabolic syndrome. Curr Hypertens Rep 2008;10:156-64.
8. Khoo J, Dhamodaran S, et al. Exercise-Induced Weight Loss is More Effective Than Dieting for Improving Adipokine Profile, Insulin Resistance and Inflammation in Obese Men. Int J Sport Nutr Exerc Metab 2015 May 22. [Epub, ahead of print]
9. Ludwig W, Phillips M. Organic Causes of erectile dysfunction in men under 40. Urol Int 2014;92:1-6.
10. Hsiao W, Shrewsberry AB, et al. Exercise is associated with better erectile function in men under 40 as evaluated by the International Index of Erectile Function. J Sex Med 2012;9:524-30.
11. Mikhail N. Does testosterone have a role in erectile function? Am J Med 2006;119:373-82.
12. Sattler F, Bhasin S, et al. Testosterone threshold levels and lean tissue mass targets needed to enhance skeletal muscle strength and function: the HORMA trial. J Gerontol A Biol Sci Med Sci 2011;66:122-9.
13. Culić V. Acute risk factors for myocardial infarction. Int J Cardiol 2007;117:260-9.
14. Chen X1, Zhang Q, et al. Cardiovascular effects of sexual activity. Indian J Med Res 2009;130:681-8.
15. Gallup GG Jr, Ampel BC, et al. Do orgasms give women feedback about mate choice? Evol Psychol 2014;12:958-78.
16. Nikoobakht M, Fraidouni N, et al. Sexual function and associated factors in Iranian patients with chronic low back pain. Spinal Cord 2014;52:307-12.
17. Bahouq H, Fadoua A, et al. Profile of sexuality in Moroccan chronic low back pain patients. BMC Musculoskelet Disord 2013;14:63-8.
18. Sidorkewicz N, McGill SM. Male spine motion during coitus: implications for the low back pain patient. Spine 2014;39:1633-9.
19. Sidorkewicz N, McGill SM. Documenting female spine motion during coitus with a commentary on the implications for the low back pain patient. Eur Spine J 2015;24:513-20
