Cross-Training – The History and Future of Transgender and Intersex Athletes (Page 5)

1920s --- Woman Exercising with Dumbells --- Image by © Bettmann/CORBIS

Let’s Get Physical

Men vs. Women – Sports Performance Differences

In terms of professional sports competitions, there are vanishingly few areas in which top-ranked female athletes can effectively compete with, or win against top-ranked male athletes. It’s undeniable that men and women, as a population, are very different physically, and many of these physical differences are relevant to sports performance.

  • Men typically outperform women by 11-18%, depending upon the type of physical activity. A 2008 study found that there was a difference in world record times and track and field achievements between men and women in various sports. The smallest male advantage was in 1,500 meter speed skating (4.7%), and the greatest male advantage was in the javelin throw (37.4%). (Devries)
  • Opinions vary on whether women can excel at extreme long-distance running, reputedly due to their more efficient sweat glands (Shy) and better body fat reserves. However, women’s marathon times are far slower than men’s – the men’s record stands at 2 hours 3 minutes and 23 seconds, whereas the women’s record stands at 2 hours 15 minutes and 25 seconds. While this is barely more than a 12 minute difference (9.7%), in the world of marathon running it may as well be an hour. The gender gap in the 50 km and 100 km events equate to 15% and 10.4%, respectively. In the 100 mile Leadville Trail run, the men’s record is 15% faster than the women’s record.
  • Women do not come close to men’s performance in the sports of weightlifting, javelin, shot put, hammer throw, and any other physical event which relies largely upon upper body strength.
  • In long-distance swimming the naturally greater buoyancy of women gives them an endurance advantage. (Shy) For all this advantage, however, men hold the records for all major long distance swimming events, as well as open-water events such as swimming the English Channel. Women have set some firsts in this event, however, such as Diana Nyad being the first to swim from Cuba to Florida without the use of a shark cage.

There are some sports in which women likely compete evenly with men, such as figure skating and gymnastics, although it is very difficult to prove this quantitatively due to the use of judging for style. In equestrian events, the small size of women gives an advantage by allowing the horse to carry less weight – however, it’s worth noting that men hold 7 of the top 10 Olympic positions in this sport for medals earned.
Charles Atlas versus Rockettes
Charles Atlas versus the Rockettes, date unknown.

Men vs. Women – Physical Differences

It’s obvious upon inspection that men in general are simply larger than women, and these differences can often be noticed from birth. (Devries) Some of these physical differences include:

  • On average, men are ten percent larger than women, being taller by 12-15 cm. (Devries)
  • Men have a greater maximum aerobic activity relative to their body weight than women, greater muscle mass overall, less body fat overall, and greater bone thickness and density. (Devries, Shy) However, in trained men and women their anaerobic capacity is the same when corrected for their lean body mass. (Devries)
  • Men have longer arms, bigger and stronger legs with more muscle fiber, and stronger and broader shoulders. Increased leanness provides a greater power/weight ratio, and greater bone mass reduces chances for injury. (Devries) After correcting for cross-sectional area, elbow flexor and extensor strength is the same between men and women. (Devries)
  • When differences in cross-sectional area are accounted for, men still have greater knee flexor and extensor strength, due possibly to having more Type II (fast-twitch) muscle fibers. (Devries) Women have a greater angle between their knees and quadriceps, the result of wider hips, which can increase the risk of injury during running, and may result in slightly less efficiency when running. However, this small difference in angle (less than 3°) is of questionable significance. (Devries)
  • Men have 10% larger hearts, lungs, and lung airways, even when corrected for size. However, although men have larger hearts their cardiac output is similar when corrected for body size. Women may also deliver less oxygen to their muscles due to having lower hemoglobin levels. (Devries)
  • Meanwhile, women have more uniformly distributed and efficient sweat glands, less body weight, and more body fat-stored on the thighs, buttocks, and breasts, making their lower bodies heavier. (Devries)

Women tend to rely on fat for energy more than liver glycogen/glucose. The root cause of this difference has been studied in rats, and is thought to be due to estrogen levels. Women also have a higher level of intramyocellular lipids (IMCL), which are available as an alternate source of energy during exercise. In total, women tend to burn fat when they exercise, as opposed to carbohydrate stores. This difference in energy utilization could be the reason why women can compete more evenly with men in long-distance and endurance events. (Devries)

Titled “Mrs. Edwards and Fraulein Kussin”

Transsexual Hormone Impacts – Transmen

Laypeople often have an idea that testosterone is akin to a speed pill, or something which can turn a milquetoast chartered accountant into the Incredible Hulk. The truth is more mundane – testosterone treatment can increase strength by 5-20%, but only when it is administered at levels above what would be found in a typical cisgender male. Testosterone is thought to reduce fatigue and enhance muscle recovery after exercise, but the evidence is weak. (Devries) During puberty, testosterone increases bone mass and density, and changes the shape of the hips. It also increases red blood cell count by 15-20%. Testosterone treatment does not appear to change carbohydrate versus lipid use during exercise. (Devries)

Transmen tend to have testosterone levels which are higher than XY men, but estrogen levels which are only modestly depressed from XX women. This combination of hormones may result in a performance advantage to transmen. However, testosterone is normally injected at supraphysiological levels, then allowed to drop to sub-normal levels just before the next injection. This high level of variation may result in negative performance impacts. (Devries)

So what actually happens to transmen who take testosterone? Studies show that hemoglobin and hemocrit content increased in the first year, then leveled off – and most importantly, at the end of the year there was no significant difference between XY men and transmen. Testosterone increased muscle mass, but not to the same level as an XY male. Only for the highest-end subjects (ones who already had a large amount of muscle prior to transition) was an XY-level muscle mass achieved. Fat content decreased in many areas, but subcutaneous fat content was still greater than that of XY men. (Devries)


Transsexual Hormone Impacts – Transwomen

While much is made of the larger size of genetic males when compared to genetic females, their larger and longer bone mass is driven by muscles which will to some extent be reduced under the influence of estrogen and lack of testosterone, and as a result a transsexual woman can end up with a poorer power/weight ratio than a genetic woman of the same size. (Pilgrim) Unlike testosterone, estrogen treatment does appear to significantly change carbohydrate versus lipid use during exercise, as well as increase levels of IMCL. Estrogen acts as an antioxidant, which can reduce exercise-induced stress and inflammation. (Devries)

Transwomen tend to have estrogen levels which are higher than average, and testosterone levels which are lower than average, compared to XX women. (Devries)

Transwomen who take estrogen and anti-androgens undergo significant changes to their performance. Conversely to what was seen in transmen, transwomen’s hemoglobin levels decrease significantly, becoming comparable to that of XX women. These changes occurred within the first year, and at three years no further change was noted. Muscle mass and cross-sectional area were both decreased, but were still larger than XX women overall. However, it was noted as in the case of transmen, that there is a large range of muscle mass among subjects. Essentially, transwomen developed the muscle mass and cross-sectional area of muscular, athletic women. Since athletes tend to be at this high end of the spectrum, it’s reasonable to state that transwomen may have a good foundation for competition with athletic XX women. (Devries) Estrogen led to transwomen increasing their fat levels, especially subcutaneous fat. However, it was still lower than XX women at one year past the start of treatment. Total body weight increased, despite a decrease in muscle mass. As mentioned earlier, estrogen changes the use of lipids and carbohydrates in the body, but most studies have been short-term, and it is not possible to tell if transwomen gain fully female trends in exercise metabolism. (Devries)


A Competitive Advantage?

One comprehensive medical and literature review did not find evidence to support a theory that transmen would compete unfairly with XY men, nor transwomen with XX women. In fact, indications were strong that transmen could not compete effectively at all with XY men, and would therefore rarely beat them in physical competition. The evidence and supposition on transwomen is mixed – while greater muscle mass may give transwomen an advantage in training, due to their starting at a higher level, there is still no evidence that an unfair advantage exists. (Devries) Body height may be the primary exception here – taller individuals have a natural advantage in some sports, and since transwomen tend to be taller than XX women, here an advantage would exist. (Devries) However, another comparison of muscle mass pre- and post-hormone therapy found that the reduction of muscle mass in transwomen was so severe that it was very similar to XX women. As a result, the authors concluded that there was no unfair physical advantage for transwomen. Another study examining transwomen who were at least 3 years post-operative found that they had less muscle mass, less strength, more body fat, less bone mineral content, and less bone density than XY males. As a result, the authors concluded that transwomen did not benefit from a significant advantage over XX female athletes. (Lucas)

Case Study – “A 6-Minute Difference”

An especially poignant case of how much hormones can change our performance was illustrated in an extensive interview with Janet Furman Bowman (the article is available for free online, and I strongly recommend it, as it’s about a lot more than running). As a man – Jim – she was a hardcore distance runner who at one time was able to run a 5:05 mile and a marathon in 3 hours and 1 minute. After a lifetime of agonizing gender dysphoria, she realized that the only way she could survive was to transition to female and become Janet.

Janet_FurmanJanet Furman

After 8 months on hormones, however, she received her first real shock about her performance. While practicing with her teammates, she discovered that she had to push herself harder and harder just to keep up with the men. Initially she wasn’t too concerned – after all, runners sometimes have significantly varying performance over time. While running her first 5k race after she had started hormones – a race she had never finished in more than 20 minutes – she gave it her all, and was astonished to find she ran in 22:43. But the bad news didn’t end there – despite all of her best efforts and training, she never again ran a 5k race in less than 23 minutes. When she was in peak form as a man, she tended to run at about the 75th percentile for men. Now, she runs at the significantly slower 75th percentile for women. In other words, her relative performance as a woman is the same as her relative performance when she was a man.

While Janet does not regret her transition in the least, she does regret that she can no longer even practice with her old gang of guys, because as a woman, she just can’t keep up. (Gorney)

Part 1 – Introduction and Early History
Part 2 – The Cruelest Test
Part 3 – Post-Richards to the Stockholm Consensus
Part 4 – Current Events
Part 5 – Let’s Get Physical (Current page)
Part 6 – Why, oh Why, Must it be This Way?
Part 7 – Are There Any Cases Where an Advantage Seems Possible?
Part 8 – Final Summary and References

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