Osteoporosis is a bone disease in which bones become brittle and weaken. Through out the human life cycle bones are remolded. From childhood from adulthood bone mass increases, but as humans age it will decrease. Both men and women can get osteoporosis, but it has a more dramatic effect on women. The reasons for this are related to biological  sex differences. Sex hormones play a vital role in bone health. There are also other factors that contribute to being at risk. The exact cause of the disease is not known, but there are some attributes of the known about the disease that can treat it.Having some understanding of the skeletal system can contribute to prevention. Humans may be susceptible to osteoporosis, because unlike other primates in the animal kingdom our bones are more porous. Bipedalism came with a price. Walking upright gave humans an advantage in evolutionary history, but meant we would have more back, foot, and skeletal problems. Certain measures can be taken to prevent osteoporosis. This is very important for women considering they live longer. Bone health becomes more critical as people reach advanced age.

        The human skeleton is composed of 206 bones. Along with the muscles, they contribute to the locomotion of the body. Muscles contract moving bones. The bones store calcium an element required for muscle contraction as well. Bone marrow produces red and white blood cells. It also has the function of producing the platelets. Bones are placed in different categories. Cortical bones include leg and arm bones that can hold and support  weight. Compact bones such as the skull and hip are stacked for fortitude. Trabecular bones which are the vertebrae of the spine act a network pathway for nerves of the body. ligaments attach bones to other bones and are flexible in structure. Cartilage is another type of tissue present in the skeletal system providing support to joints. Men and women have the same bones, but there are structural differences. Men have denser bones and broader shoulders. Women have wider hips and less bone total bone mass. This also explains why on average men  are stronger. Muscle fibers need skeletal support for motion and the bone mass contributes to total body force. Between the ages 1 to 13 bone mass and muscle composition is equal among boys and girls. When puberty occurs, testosterone causes muscular hypertrophy and a increase in bone mass in boys. Skeletal mass continues to increase in both sexes between the ages of 20 to 30. The rate of bone formation is greater in youth. Around the ages 40 to 50 their is an equal rate of bone breakdown. Formation does not occur at the same rate at the time of youth. Bone mass will decrease due to a higher rate of reabsorption.

Women have less bone mass as compared to men. Peak bone mass for women only reaches an estimate of 1000g as compared men’s 1500g.

   The formation rate cannot keep up with the loss that is occurring with age. The reason for the disparity is that men have a larger amount of bone mass. Men can lose up to 25 % of their bone mass while women can lose 35%. The skeletal system just like other organ systems can develop health issues.

         Endocrinology explains the reason for women’s higher rate of osteoporosis. Sex hormones promote bone strength through out life. When testosterone and estrogen levels decline problems arise. Men’s testosterone levels decline slower and by age 65 drop significantly. Women’s estrogen levels start to decline as early as age 45. This means women are at greater risk for fractures in the cortical bones, pelvis, and hip vertebrae. This is a disease that happens when people age, which explains why it is rare to see younger people with it. Children still need regular exercise to build up as much bone mass as possible to prevent this disease.Even though men are at a lower risk, it is still something to be conscious of. It is possible for menopause to cause some level of bone loss.After menopause resorption occurs faster than bone production. Women can experience this with early menopause or infrequent menstrual periods. It can also happen if women’s estrogen levels get extremely low.


 Hormone replacement therapy has been recommended for women who have less than average bone mass , early menopause, or a genetic history of the disease in their family. Hormone replacement therapy has risks of its own and that is why prevention is normally favored.

        There are methods that can be utilized to prevent osteoporosis. Getting adequate calcium in your diet can help. The U.S. National Institutes of Health recommends 1,500 mg during puberty  The amount for adults is projected at 1000 mg. Past the age of 65 the intake should be about 1,500 mg. Vitamin D is also an essential part of bone health. Sunlight is important to this process, because it synthesizes a precursor to vitamin D. Calcium is important to a person’s diet and can be found in dairy products. People who have lactose intolerance consuming leafy green vegetables , broccoli, and salmon. These foods contain high amounts of calcium and aid in other nutritional needs. Yogurt or cheese can be an option if digesting milk is too much of an issue. Lactose free dairy products are also available as an option.

Fresh air is good for you in more ways than one. Some areas during winter do not have enough sunlight so it would be difficult for the body to produce vitamin D. The woman here would have no trouble producing vitamin D here, because she is on a sunny beach.

 People who live in the global North and experience long overcast winters should be conscious of their vitamin D levels. Milk ( low fat ) and cereal contain vitamin D, which can make up for the lack of sunlight. Other supplements and medicines are more helpful. Diet is important, but exercise is also required as a prevention measure. Moderate activity can build bone mass. Inactivity causes problems for the body. Inactive individuals who are confined to bed can lose up to 25 times more bone mass compared to active people. The body is designed for physical work and use. Not using it causes decline. Muscles atrophy if not used or exercised. The skeleton which is just as pivotal will also struggle to perform formation of new bone. When people reach adulthood the skeleton will constantly be broken down by osteoclasts  and rebuilt by osteocytes. Old bone matter is replaced by new bone through a remodeling.

Being confined to a bed or inactive for long periods of time causes a person to lose skeletal mass. This is a concern for patients in a hospital. Muscle mass can be lost from inactivity.

The exercises that promote optimum bone health  are weightlifting, walking, or jogging. lifting weights does not only build muscles it can reinforce bone. Being active in youth can prevent bone mass decrease. Doing this also provides other health benefits. It can manage weight  and maintain a healthy circulatory system.  To understand the nature of how delicate the skeletal system is, the bone growth process needs to be examined. A majority of bones are made of cartilage during the prenatal development. The cartilage structures are formed into bones by calcium salts stored in a matrix. Osteoblasts are the cells responsible for bone formation. This causes endochondral   ossification, which means replacement bone will be formed in the body.  The rate of growth is controlled by sex hormones and growth hormones. Growth plates are located between the primary ossification center and each secondary center area. These centers at one point will fuse and the skeleton will reach full growth.

302917684 runwalk

Osteoclasts  deposit calcium in the blood. Their role in maintaining calcium levels contributes to the homeostasis of the skeletal organ system. Osteoblasts must replace the retired cells. They take calcium from the blood to form new bone matter. The cells get caught in the matrix and form osteocytes.  The human body is a hard working organic  machine.

      Although osteoporosis can strike many individuals, certain groups  are at risk. Individuals who have a slender body type are  at risk. The ectomorphic body types are ones that contain low levels of bone mass. Having less body mass means the skeleton can be weakened more from the disease. Fractures are a major concern for people with osteoporosis. For thin boned people it could be more devastating.People erroneously associate thinness with health, but that in this case is not truthful. Being white or Asian can mean that getting the disease is more likely. This does not mean every person of that race will get it. The likelihood just increases due to genetic traits among  these groups. Family history plays a role in the risk factors for osteoporosis. Genes allow you to inherit various traits and this can apply to predisposition to certain diseases.

Although Tomoko is Asian that does not mean she would get osteoporosis. Doing the proper health procedures can prevent various diseases.

 oddly enough being a smoker can also contribute to increased risk factors. It is well known that smoking can cause harm to the lungs and respiratory system, but it has the ability to increase the chances for osteoporosis.  Alcohol and high caffeine consumption can also be risk factors. Smoking and drinking do not only harm one organ system; many can be effected by excess consumption. Alcohol can damage the liver and effect the health of your skeleton later in life. Taking note of these risk factors can allow individuals to control their biomedical condition.

          Measuring bone density is a method of detecting if osteoporosis is present. One method is the dual  energy X-ray  absorptiometry.  Bone density is measured by the amount of photons absorbed by the bone from an X-ray tube. Blood and urine tests are conducted to examine the biochemical nature of the subjects bone. If a marker appears that indicates the bones are too thin a physician will recommend treatment. Hormone therapy is one suggested treatment. The use of black cohosh or phytoestrogen, which is estrogen produced by a plant. Calcitonin  can be utilized, which can inhibit the osteoclasts. Preventing the osteoclasts from breaking down too much bone and allow for more to be restored. Alendronate therapy acts in a similar fashion. It attempts to build bone to prevent further fractures. Three years of this treatment has shown that spinal density can increase about 8% and hip density about 7%.  These are older treatments and biomedical science continues to advance rapidly. Knowing  the nature of the skeleton and its disease can stop possible health issues.

Further Reading

Mader, Syvia. Biology. New York: McGraw Hill, 2007.

“Menopause & Osteoporosis.” Cleveland Clinic. N.p., 8 Aug. 2015. Web. 5 May 2016. <http://my.clevelandclinic.org/health/diseases_conditions/hic-what-is-perimenopause-menopause-postmenopause/hic_Menopause_and_Osteoporosis&gt;.


Jackie Joyner Kersee

Jackie Joyner Kersee  was a track and field athlete who dominated the women’s heptathlon.  To many she is one of the greatest athletes to compete.Her accomplishments are numerous and her life story is one of intense perseverance. She was born in 1962 in East St. Louis. Her family struggled financially. Her mother was a nurse and her father was a railroad construction worker. Although her family did not have much, they always provided her with love and support. They encouraged her to do well in both her academics and sports activities. Kersee showed her abilities at a very young age. At age 12 she was able to leap more than 17 feet. Kersee developed her early athletic abilities at a local recreation center were she learned dance and track. Jackie Joyner Kersee despite these amazing athletic talents has asthma. Her earliest successes were winning the National Junior title between the ages 14 and 17. During high school she played both basketball and volleyball. She would then go on to attended the University of California at Los Angeles, receiving degrees in history and communications. There she played basketball and ran track. She would later be coached by Bob Kersee who would later become her husband. Her rise to prominence began in 1984. She competed in the heptathlon event winning a silver medal. She lost getting a gold by just five points, but that gave her motivation to improve. A personal motto of her’s was ” I’m a firm believer in the tree Ds- determination, desire, and dedication.”


Kersee was a type of person with much resilience. Second place was a concept that was not conceivable to her. She then developed a new strategy and continue to train for her next competition. Standing at 5 feet 10 inches and  146 pounds of muscle Jackie Joyner Kersee embarked on a long and successful athletic career.

        Jackie Joyner Kersee returned with impeccable performances. At the Goodwill Games in Moscow  her score 7,148 amazed fans and fellow competitors. That was only a small sample of more amazing athletic feats. She increased that previous score ten more points. The 1986 proved that she was going to be a powerful force in the 1988 Olympics. Kersee continued to break records. She won gold medals in the 1988 Olympics in the long jump and heptathlon. Even with an injured knee she was able to gain 7,291 points in her athletic events. The 1992 Olympics also brought her success. There she got a gold medal in the heptathlon and a bronze medal in the long jump. Kersee had won multiple events in three Olympics and no athlete has ever done so. Kersee has stated one of her objectives was to “open the doors for minority women and women in general.” Growing up during the 1960s when opportunities were limited for African Americans and women left an impression on her. She struggled, but she wanted to improve her community and give back to it. Jackie Joyner Kersee from the early 1990s to present has been active in philanthropy and charity. The Jackie Joyner Kersee Community Foundation continues to provide educational and recreational sports programs  for youth in the East St.Louis area.

_Jackie Joyner 1992
Learn more about The JJK Foundation here:  The Jackie Joyner Kersee  Foundation .

Her athletic accomplishments got her television exposure and endorsements. During her  athletic career and after she serves as an excellent representative for women’s sports. When she was competing the public still held dubious and sometimes negative views in regards to women in sports. Jackie Joyner Kersee had the talent, charm, charisma and beauty to challenge stereotypes and myths. Her last Olympic competition was in 1996. Unfortunately a leg injury cause her to withdraw. However she did win a bronze medal in the long jump before  the hamstring injury became unbearable. Her athletic pursuits did not end there. Kersee would play basketball for the Richmond Rage under the American Basketball league. She would play a total of seventeen games, but was not as much a success as in her track and field career. Kersee would return to track  in the Goodwill Games of 1998. There she scored a total 6,502 points. Lower than her previous scores, this is still quite impressive. Athletes who compete pentathhlon  or heptathlon rarely win past the age of 34. The years of top physical performance are between the ages of 18 and 30. For Kersee age is just a number and she still loved to compete.


Kersee attempted to qualify for the long jump in 2000 for the Sydney Olympics. She finished sixth and failed to qualify. It was a long competitive career from 1984 to 2000. Kersee continued to be involved in the sports world even after retiring from active competition.

        Jackie Joyner Kersee currently is on the board of directors for USA Track and Field. It is the governing body for the sport in the United States responsible for rules and various regulations. She along with other athletic professionals founded  Athletes for Hope  another charity that encourages athletes to give back to the community. Besides that it helps with coaching and assisting athletes from the very young to the more experienced. Non-profit organization work seems to be her competition now and promoting a positive image of the sport. Track and field does not get as much exposure as football, soccer, or tennis. Having a famous figure like her promoting it could get more of the public interested. Jackie Kersee also wrote an autobiography chronicling her career and early life.

 With the assistance of Sonja Steptoe A Kind of Grace : Jackie Joyner Kersee the Autobiography of the World’s Greatest Athlete was published in 1997.  This was the first book in her own words describing the triumphs and challenges through her life and career. Like most autobiographies there is a level of embellishment when describing certain events. However, when you reach a high level it can be forgiven.

       Jackie Joyner Kersee has been named by Sports Illustrated ” the greatest female athlete of the 20th century.” That title is well deserved. Her personal bests are a testament to a skilled physical prowess. Her long jump best was 7.49m. Kersee 100 metres hurdles was 12.69 s. Her high jump was 1.93m. Kersee’s shot put throw was 15.80m. Her 200 meter  event was a time of 22.56 s. Her 800 meter event time was 2 minutes and 8.51 s. These top performances amounted to a total of 7,921 points. Certainly she has made an impact on sports history and women in sport. There still remains the conviction that women are not serious contenders in the sports arena, but Kersee effectively destroyed that notion. The sports community has recognized her and she boasts multiple awards. She won the James E. Sullivan Award ( 1986), the Jesse Owens Award ( 1986 and 1987), awarded the Order of Lincoln (2005),  and the Dick Enberg Award (2011). There continues to be recognition of her and hopefully history will document and preserve her feats as well.

         Jackie Joyner Kersee has stated ” I never viewed sports as unfeminine I’ve seen it as a saving grace.” What she meant was that it was a gateway for her to advance herself. She also faced racist prejudice from other competitors and negative commentary from individuals spiteful of an African American having success. She once said “that it is important to expose children to thing they think are off limits to them.” African American children especially, in her view should understand this even though an American society is generally hostile and exclusionary. Walls as she once said are personal barriers we put up. They only stop you if you let it.


 Jackie Joyner Kersee was proof that the Title IX legislation was effective at getting more women into sports. The women of the current Olympics owe so much to her and the athletes than came before. Kersee realizes the importance of social justice and that is why she has devoted most of her to philanthropy. Although very busy, she still finds time for fitness. Many retired athletes still train, because they love their sport so much. Her philosophy on training is quality versus quantity. Quantity is the total amount of training, were quality targets specific physical fitness elements. Kersee prefers quality now, due to the fact she is no longer competing. Her exercise regimen she describes as this: ”  I try to get a 4-mile walk in — which should take about an hour — then do some weight lifting. I like doing 200-meter intervals on the track, a circuit in the weight room or anything dealing with cardio or pumping the heart.” Kersee’s advice to new athletes is in her words “learn to listen.” Vital information can be acquired if one takes advice. When an athlete wins on multiple occasions sometimes they feel that they know best, but there is always more to learn. Kersee does not want others to follow in her footsteps, but to find their own way. Humble even though a prominent figure, she rarely makes TV appearances and occasionally does public speaking. Jackie Joyner Kersee is what an athlete should be, persistent, honorable, and contributing to the community.

Jackie Joyner Kersee

Thinking Girl- “Weaker Sex”

The Thinking Girl- “Weaker Sex”

This is a blog entry from Thinking Girl, originally published in 2007. This is noteworthy because third wave feminist tend to take issue with biological and physiological differences. One difference is the gap in physical strength ( on average). Some try to say that is based on environment or solely on biology. The fact is it can be a combination of both. Denying biological differences is not constructive. The fact that women and men are different does not mean women are inferior by default. The writing makes this mistake, but starts off with a rational argument. She says that their is a relation in regards to power language. Eloquently the author points out ”  why say “weaker” instead of something else, like “gentler” or “peacefuller” or something.” The author then questions the concepts of strong and weak in the context of language. It is the most cogent argument, yet it seems the author is hostile to biological facts. Many feminists would do well to embrace biology and physiology as a means of disproving the concept of female inferiority.

        The  author understands that power language here is used to designate the other. The concept of the other is used to either marginalize or exclude different groups. Using this type of language then becomes coded for treating certain people horribly in an inconspicuous manner. She poses a great question : “why  should it be that “men are strong and women are weak,” instead of “women are not quite as strong ?” The answer is that it is a way to dehumanize women and denote a lower status. Saying a woman is weak demonstrates the belief they are not capable of various tasks. It also can serve to say that women are helpless and child like needing male supervision. Legally, many countries functioned of the idea of protectionism. This was a legal conviction that women had to be protected from the harsh realities of the world and relinquish their free will or rights to a husband or male relative. Power language as the author explains is designed to control groups and using a false binary to gain consensus among the oppressors.

          The article does ask the question what is strong. It is obvious the discussion is in the context of physical strength. Then she states “those who like to point out the biological differences between men and women (as if that’s justification for the widespread social oppression women experience) usually like to point this one out, like it’s a given.” Anatomical and physiological factors show that on average men are stronger than women. Men have larger skeletons and bone mass. Their bodies contain higher levels of type II muscle fibers. Testosterone induces higher levels of protein synthesis. There is a period that boys and girls are equal in strength levels. When puberty occurs males experience a strength spurt in which skeletal muscle mass increases. Leydig cells produce more testosterone in the testes. The bones become more dense  and the muscle fibers increase in length and width. The process is done by age twenty for men.


 This however, is just an average. The author the goes on to say “And of course there are women out there who are plenty strong, stronger than most men, women who bodybuild and are athletes and things like that.” Oddly she then expounds further :”but of course, these cases are atypical, so shouldn’t be considered to be counter-examples. We’re talking about the general “truth”, so they say.” there are many women who are participating in sports or just average women becoming interested in strength training. Although their numbers are not as large, their is a sizable portion. This contradicts her previous statements because these women be good examples to her point. At this point the reader should ask one question: why are third wave feminists concerned about men’s physical  strength?

Women are no longer afraid to work out with weights.

There could be several explanations. The first has to do with power feminism. The basis of this feminism is that women should not seek equality as what is generally understood, but amass as much power as possible. Generally observers see this as gender antagonism rather than empowerment. The power feminist would seek to get women in a race  with men for physical strength. This is an unhealthy mode of thought, because it believes might makes right. It functions on the notion all men are women’s enemies and must be challenged in every area of life. This area of strength would be difficult to antagonize men in due to biology. The other explanation is more irrational. There are some third wave feminists who could be jealous of men’s strength. They feel that nature made some error and that differences allow inequality to continue. There is either a feeling that they are missing out on something. This belief is ludicrous. It would be like men being jealous of women, because they can get pregnant. Some of the frustration can be understandable. There are men who complacently use physical strength as “proof” that men are superior. The one piece of information they do not speak of is that a woman can gain strength through a training regimen and can be strong as or stronger than the average man.


. A more accurate and plausible concern third wave feminists  have is that women face serious abuse. Women face rape, domestic abuse, and violence from men. That why some obsess over the topic physical strength. If one’s physical safety cannot be guaranteed their can be no freedom. Women being smaller than men means they are at a disadvantaged when attacked by a male assailant. Even worse, women may have to consider possible danger scenarios when becoming close to a man in an amorous relation.  Very few men worry that their wife or girlfriend might harm them. Women have to deal with this unfortunate reality.


There can be effective resistance  to violence against women. Self-defense, tougher laws, and a change in mindset are excellent weapons at combating this problem. Knowing how to defend one’s self ensures your security. Tougher laws keep criminals in prison. A change in mind set allows women to stop seeing themselves as victims, but capable survivors. This may not eliminate the problem entirely, but reduce it.There is one dynamic the author never considers. When a physically powerful woman is compare to a man of less strength, why is he valued more. The author recognizes that a society does value men more than women, but does not ask why. The reason is based in misogyny and the conviction that women are only exist to serve men. This concept can be seen in religion and social order of society. Marriage throughout history was a property arrangement. Women were not allowed to receive education in many states at one time. Women had limited access to economic and political power. As Peter Farb  stated in Humankind    “none of the biological and psychological differences between the sexes would seem to account adequately for the dominance of males in all societies.” Physical strength is not a social construction, but an element of sexual dimorphism.

No one would call the much weaker man inferior, when compared to a stronger woman. She is faced with ostracism or public rejection. The double standard and over exaggerated reactions reveal that society still has a high level of sexism. This does not come just from men, but other women with a more traditional view point of gender roles. It is critical to understand, not reject biology of sex to better discredit false beliefs and extremist notions.

        This written post does point out the social barriers, but some statements are not entirely truthful. The cogent arguments are undeniable. The first social barrier is ” girls are taught that sports are a bit “butchy” and unfeminine.” This is a combination of homophobia and sexism that turns many women away from sport. Real women in this view do not engage in “manly” activities. Women who do are considered by a sexist society  lesbian or out of control. This has been challenged with a greater acceptance of people of different sexual orientations and women changing the context of what is feminine. The socialization happens at an early age encouraging boys to get involved in athletics, but not girls. Boys she points out a fed more  and encouraged to play roughly. Then the author describes that body image is one issue that plagues women. It is an unfortunate state of affairs. There are problems with other aspects of the author’s argument. She disparages gymnastics as being “proper ways to express one’s girl self.” Gymnastics is a highly competitive sport and it is producing quality athletes. It takes strength, dexterity, and fast body coordination to perform such moves.

Gabby Douglass
Gabby Douglass showing her advanced skill.

 Gabby Douglass Olympic gold medalist has proven that gymnastics is a sport of talented individuals. Her performance in the sport dazzled and amazed an international audience. She rose to prominence in 2008 becoming part of the U.S. National Team. Dance is artistic being employed in the music industry and the performances arts. It can be useful to sports as well. One example is how some bodybuilding incorporate dance moves into their posing routines. Colette Nelson had a background in dance, which added substance to her posing routines. Besides just having size, shape, symmetry, and definition the way the physique is presented can make the difference in point accumulation.

colette nelson
Colette showing her dancing abilities.

 Dance and gymnastics should not be seen as frivolous. The only reason someone would view these two areas negatively is because they dislike the idea of women excelling. The author then says that women have few role models and not every sport has a league or division  for women to be active in. The claim is only a half truth. While it is true the mainstream media does either ridicule or ignore female athletes, there is a slowly growing interest. There are fans out there who are not getting access to events on TV and turn to the  internet. That is the wave of the future for entertainment. It makes no sense why sports or entertainment corporations do not attempt to capitalize on this. Role models are prevalent, but the media does not want to promote them. There are some cases in which an athlete is so good they cannot be ignored. Rhonda Rousey  has  by her athletic successes and media appearances brought the UFC to mainstream prominence. Her efforts have made mixed martial arts more acceptable in a sports television line up. Now there is an interest in  MMA  by the public. Serena Williams continues to make strides in Tennis. She was name sports woman of the year in 2015 by Sports Illustrated.  These are just two women who have had massive impact on the sports world.  The problem is media exposure. ESPN does not broadcast as many women’s events. It’s not that do not exist, the media is not showing  the viewers new athletes or ones that are emerging. The only solution is to either for women to start a sports channel of their own or generate interest through public relations campaigns.

There is a period of transition that is occurring. There is at least some level of recognition for physically strong women. This should not be confused with complete acceptance, but there are people who support what they do and are devoted fans. The concepts of body image are also being adjusted to a motto “strong is the new skinny.” The women of crossfit are even gaining at least some attention. The old problems still remain. There has been progress and it will not be stopped. Women are even becoming involved in American football. Women have organized their own teams and play. The NFL does not have a women’s division in which they can play separately. However, there are women who love the game that much they willing to start their own organization. It is probably for the best free of corporate or sponsor control.

There are women who have organized teams under the United Women’s Football League. They are attempting to get television coverage and media exposure.

 The fact that the UWFL does not get recognition just demonstrates how women are marginalized by the entertainment and media industries. Women should start their own companies if the current mainstream business do not provide coverage. The world will soon realize that women are valuable. Economically, it has been realized because nations who do not mobilize women in the workforce  will struggle financially. Change is happening, maybe not as fast as many would like it. As long as it is happening at whatever rate, this show that someday the objective of equality will be reached.

          The author then poses the question “how much of this is biologically driven?” That is not a simple answer. Strength and or athletic ability is dependent on genetics and environment. Men have more physical strength due to endocrinology and traits of the SRY gene. This does not mean women cannot improve or enhance their physical strength. Muscle histology is the same for both sexes and both respond to weight training in a similar manner. It would be ludicrous to say that every man is stronger than every woman . It would be difficult for an average man to out run a female track star  or out lift a female weightlifter. Biological differences have no stopped women from entering profession that require physical strength. The military, police, sports,construction, and firefighting have women in small numbers. The small numbers does not mean that women are horrible at these jobs, but that physical tests are more difficult for the majority of them. When adequate training and exercise is part of their regimen some of the difficulty is reduced. Even for women that do pass, they still face harassment and discrimination. The explanation is not purely biological or sociological it is a combination of both. The author should not use social construction theory as an explanation for all aspects of discrimination. Peter Farb  once wrote ” males exhibit greater aggressive behavior than do females in part because of hormones- but in part also because of norms of a particular society .” This is interactionist theory. Understanding this can dismantle sex stereotypes and pseudoscience that is still prevalent.Third wave feminists should not try to deny biological differences or reject the life sciences; they should be embraced  to discredit misogynistic convictions.

Thinking Girl- “Weaker Sex”

Muscle Fibers

Muscle tissue consists of various fibers. Each person has a unique composition of muscle fibers, which does effect athletic performance. There are three major types of muscle fibers. These include type I fibers, type IIa fibers, and type llb fibers. Depending on the sport athletes may have more or less of a certain type of muscle fiber. The human body is an incredible organic machine with different functions. It is pivotal to understand the characteristics of muscle fibers to tailor specific training regimens.

           Muscle fibers are located in the fassicle. The fibers are secured by the endomysium. The muscle almost forms a structure that is similar to a fiber optic cable. It is bundled by a network of wires. These types of wires are supported by both bone and tendons. There is also a network of blood vessels running through the muscle. The epimysium acts as cover for the perimysium of the muscle. The movement of the human body can only happen when tissues contract. When discussing major muscle fiber types, they are mostly regulated to the examination of skeletal muscle.


Sometimes it is referred to as voluntary muscle. These are muscle that respond to the conscious control of the brain. Chemical messages can either direct them to contract or lengthen. When viewed under the microscope they have a striated or striped texture. All of these microscopic fibers work together as one unit in the muscular system.

        Type I muscle fibers are normally called slow twitch. Their speed to contract is lower compared to other fibers. This slow contraction time allows for better performance in endurance events. The force out put from these fibers is low. They do contain high amounts of mitochondria which assist with oxidative metabolism. Slow twitch fibers are more fatigue resistant. The slow twitch fibers are red from the iron in cytochromes. They also contain a large amount of capillaries in their structure. Endurance athletes such as marathon runners,distance cyclists, and cross-country skiers could have up to 90% slow twitch fibers. Athletes with higher amounts of slow twitch fibers will have higher VO2max results. This means an endurance athlete will have higher aerobic capacity.

Mary Keitany
This marathon runner would have more slow twitch muscle fiber composition.

The average person can contain up to 50% slow twitch fibers in their body. Like other fibers they can be built through a specific type of training. Slow contraction is an advantage, because they keep the body going. This gives dedicated swimmers an advantage in endurance. Endurance exercise allows the muscles not to get worn out fast during physical activity. Other benefits include improved coordination, a larger heart which can pump more blood,  and maximizes metabolic efficiency. Oddly enough, it is believed that endurance exercise can improve digestion. Slow twitch fibers are not useful in sporting activities that require explosive power. muscle_fiber_pic   A cyclist or a swimmer attempting to enter weightlifting may struggle if the training regimen is not adjusted. The role of oxygen is critical, due to the fact  it produces energy for muscle contraction. Even though slow twitch and fast twitch muscle fibers are different muscle fibers follow a basic anatomical structure. There are myofibrils, which contain actin and myosin filaments. There is also the nucleus structure and striations present. Myofibrils are divided into sarcomeres. They are by nature contractile. When myfibrils contract sarcomeres shorten. This subsequently results in actin filaments to move past myosin filaments shrinking the H zone. This happens when the muscles contract.

This cyclist when doing this activity is constantly contracting sarcomeres.

 When examining this part of the body, it demonstrates how the body is like an organic machine. The body is constructed of smaller units known as cells which form organ systems that collaborate to keep a life form functioning. Muscle fibers play a role in this process, besides assisting in athletic activity.

       Fast twitch fibers function better in strength sports. They are know for their fast contractions, but can fatigue quickly. Their ability to generate action potentials is very efficient. The higher level of myosin ATPase allows for a larger release of calcium  and uptake by sarcoplasmic reticulum. Fast twitch fibers are suited best for basketball, soccer, hockey, track and filed, and powerlifting. Fast twitch fibers can be divided into two groups: type IIa and type IIb. Type IIa has more muscular force, fatigue faster, and functions on a different energy system. The glycolytic energy results in anaerobic glycolosis which produces ATP. ATP is responsible for supplying a sufficient source of energy for muscular contraction.Type IIb are known for having a high fatigue rate, but have the greatest explosive power. They are the fastest of all the muscle fibers. Physical activities that require a massive burst of power will recruit type IIb fibers. They are summoned last when muscle recruitment is required. Slow twitch fibers go first, followed by type IIa. Finally, when those fibers can no longer sustain pressure type IIb is recruited. This results in the burst of maximal strength. That is the total strength the body can produce. The body contains a general strength reserve. Lifting a carton of juice would not require maximal strength. Lifting a huge weight or a person would.

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This is the demonstration of type II muscle fibers in use.

A contraction from a type IIb muscle fiber can last up to 7.5 milliseconds. This is a short period of time for the burst of power to be released.  This means a weight lifter would struggle with an endurance event. The muscles would fatigue at a faster rate. The strength athlete who tries to compete with a runner would find themselves in a real challenge. The runner would most likely have trouble generating a huge bursts of physical power. All these fibers work together producing skilled movement which is directed by electrical impulses in the brain. Diameter of the fibers does effect the force of muscle fiber. Fast twitch muscle fiber has a larger cross sectional area and can therefore generate more force. Slow twitch fibers have limited potential for high levels of muscular hypertrophy.

Here she is using her maximal strength.

There also remains aspect. Sexual dimorphism also does play a role in the distribution of muscle fibers. This does effect athletic performance between the sexes.

Contrary to popular belief, men and women have the same muscle tissue. There are a total of 700 skeletal muscles in the human body which account for at least 40% body weight of the average person. The anatomy of the muscle is the same for both sexes. The difference is that one sex has more of a certain type than the other. The fibers are still the same, but it depends on genetics and which type of exercise an individual engages in. Men have more fast twitch fibers. This is an explanation why men are on average stronger. Women have more slow twitch muscle fibers, which means they are more fatigue resistant .  There is a difference in upper body strength seeing as men have more of a concentration of fibers in that part of the body. Higher skeletal volume means more output. Estimates vary, but a woman of the same height and weight  of a man can be close to 80% of his body strength. That 20% difference reveals that a woman is closer to a man in lower body strength. Testosterone has an enormous impact on protein synthesis. Estrogen forms more fat. Even the most muscular female still carries a higher fat percentage than a man.

   Muscle fibers both fast and slow twitch have even more distinct attributes. The reason for fast twitch muscle fatigue is that lactic acid will accumulate (anaerobic glycolosis process). Acidosis occurs causing fatigue of the muscle fiber. Muscle fibers utilize blood supply in a different manner.Slow twitch fibers have excellent blood supply as compared to fast twitch fibers. Slow twitch fibers get their outlandishly red appearance from the abundance of blood supply. Fast twitch have less blood supply to work with having a white appearance. Lack of blood means a limited supply of available oxygen.  Besides the difference in oxygen, it is fascinating to how it relates to mitochondria. This organelle is important to human life Most eukaryotic cells carry mitochandria. Their total number can vary depending on certain types of activities. They can change shape to be either longer or thinner depending on the circumstance. Mictochandria provide energy where it is needed. Fat cells contain a small number and fat storage does not require energy. Mitochandria are referred to as the “power house” of the cell, seeing as they produce adenosine triphosphate. Slow twitch fibers have more mitochandria, while fast twitch have less. This effects energy reserve for the different types of muscle fibers.There are fuel sources that fibers are reliant on. Slow twitch use glucose and fats, while fast twitch uses ATP derived from glucose. Depending on what sport an individual goes into it is critical to have an understanding of muscle fiber and its histology.

Further Reading

Mader, Sylvia. Biology.New York: McGraw Hill Companies, 2010.

  Clark, Shannon. “Muscle Fibers How They Differ.” Bodybuilding.com. N.p., 7 Mar. 2007. Web. 5 May 2016. <http://www.bodybuilding.com/fun/sclark20.htm&gt;.

Dale, Patrick. “Difference Between Slow-Twitch and Fast-Twitch.”LIVESTRONG.COM. LIVESTRONG.COM, 25 June 2015. Web. 04 May 2016. <http://www.livestrong.com/article/454134-difference-between-slow-twitch-and-fast-twitch/&gt;.

Muscle Fibers