At one time it was thought that males contained more muscle fibers required for elite weightlifting. A sports science study has challenged this assumption showing that elite female weightlifters either had the same amount and in some instances more. Rarely do exercise physiology studies focus on women athletes and this may be the first of its kind to study female strength capacity. The experiment was a collaboration between San Francisco State University, California Sate University, and Fullerton researchers. The results of the study were published in PLOS ONE. The results of the study should not be an immense shock. There are many factors that are related to physical strength. Muscle fiber type distribution can vary among individuals regardless of biological sex. However, it seems that the frailty myth persists along with other fabrications about women’s bodies. Jimmy Bagley professor of kinesiology commented “despite no high-level data, people thought that women had fewer fast twitch fibers and that was seen as a negative thing.” Seeing the results of the study has shown that claim is false. There are certain factors that could effect data. It seems so far, women may have more athletic and strength potential then realized.
A basic understanding of cytology is required to fully comprehend the significance of this discovery. The human body has three types of muscle fiber cells. These muscle fibers have a variety of proteins known as myosin heavy chains. The myosin heavy chains function similar to a motor enabling locomotion of the muscles. Muscle fiber classifications include MHC I ( slow twitch) and two specific types of fast twitch fibers. The IIa have more force generation. The IIx fibers have the ability to generate force, yet it is done at a higher rate. Certain muscle fiber aid an athlete better depending on the sport. Marathon runners benefit from having more type I muscle fiber. Powerlifters need type II to move enormous amounts of weight. The muscles of men and women do not differ at the cellular level. This means muscular contraction and the process of muscular hypertrophy functions in the same manner. This puts to rest the idea that there are men’s muscles and their are women’s muscles. When viewed through a microscope, it would be difficult to distinguish male and female muscle tissue.
The muscle type that is of particular interest to this study is skeletal muscle. Skeletal muscle is voluntary in terms of movement requiring conscious control. This muscle type normally is attached to bones. Skeletal muscle also contains endomysium, a connective tissue that encases each fiber. The perimysium bundles muscle fibers into units known as fascicles. The epimysium acts as a support barrier. The anatomy and physiology relative to skeletal muscle are the same in both sexes. There is however, a difference in strength between men and women. Muscle quality is just as important as amount.
The study conducted a biopsy taking tissue samples from male and female weightlifters. Muscle fiber was extracted from the thighs of athletes. Six Olympic female athletes and nine national caliber athletes contributed samples. Only six males national caliber athletes contributed to the sample. The problem is that there are not equal numbers of men and women in the comparison. There are a wide variety of women, yet only a few men to compare them to. It could create distortions. If this were to be a biological fact a study should examine both men and women across various fitness levels. The highest performing provides at least a small sample to work with. The data was gathered from the 2017 World Weightlifting Championships. The women reported to have 67% fast twitch muscle fibers. Two of the world class and Olympic female lifters had 85%, which is more than any of the men in the sample. What can be concluded is that training and body mass can determine the amount of fiber fast twitch fiber rather than sex. The notion that muscle fiber type was an attribute one was born with and was unchanging appears to be false. Training can be very effective at enhancing physical fitness capacity in regard to strength.
One wonders why men still have higher levels of strength when training regimens are the same. Alumna Kaylie Zapanta weightlifter and participant in the study brings the explanation down to body composition and hormones. The most muscular women still carry a higher body fat percentage compared to their male counterparts. Fat cells unlike muscle cells are not capable of generating extra force or muscular power. Male body composition has more muscle compared to women. Endocrinology has an influence on strength as well. Sex hormones perform various functions. When boys enter puberty their testosterone levels increase. Bones and muscles are change dramatically. Both boys and girls experience growth spurts. The size of the skeleton does have an influence on strength. Seeing as the skeleton acts as support a large skeleton means more muscle can be contained on certain parts of the body. For awhile girls may actually have a height advantage completing their adult growth faster.The difference with boys is that during their slower growth a strength spurt occurs. The shoulders become broader and muscle mass increases. Testosterone increases protein synthesis enabling muscles on a male body to become bigger through training. The stereotype is that women are not capable of anything that requires physical prowess.Besides the basic endocrinology somatotype can be a large determinant regardless of sex. A woman with a mesomorphic body type has more strength potential than a man with an ectomorphic body type.
This opens more possibilities. Further studies could be conducted to explore the similarities and differences relative to ligament and tendon strength. Doing so could allow for more solutions for preventing ACL injuries in female athletes. This study demonstrates that the muscle fibers of men and women are not radically different. If another study was conducted a biopsy would have to be done. Then from those samples show it to other subjects and have them guess if the muscle fiber is either male or female. They would have to have no knowledge of where the sample tissue came from. There still remains much to learn about the physiology and anatomy of the human body. The progress in muscle histology has been extremely slow. Stefano Lorenzini noted in 1678 that there were both red and white muscle fibers. Strange as it was, he was a Physician not a histologist like Louis-Antoine Ranvier . It was the year 1873 that he was able to confirm two distinct myofiber types in vertebrate skeletal muscle. Skeletal muscle biopsy procedure became a useful tool in exploring the physiology of athletic performance. This technique was reintroduced in 1962 and since then has been applied to sports science studies. Women have the most to gain from this in terms of improve athletic performance.