Originally Posted by CTKook
...but you don't go on to note all the other effects of T that are well-documented, mentioned in wiki, and not mysterious. It's not just for building muscles. Again, known fact, and in that thing known as the real world not controversial, at least away from college campuses.
Originally Posted by PlugBootBlues
So each myocyte has the same number of contractile proteins if it is the same size? I thought testosterone binds to nuclear hormone receptors in muscle cells and induces synthesis of actin and myosin (contractile proteins), thus making the muscle stronger. So, therefore, it is much easier for men to get bigger and stronger. As such, Lindsey vonn is squatting what JII boys squat.
And this doesn't take into account type I, IIA, and IIB muscle fibers (fast twitch, and slow twitch).
Originally Posted by CTKook
T's augmentation of neural activation adaptions in trained athletes is also worth thinking about. IF people are interested in the actual, real world picture of what T is and does.
CT, your cherry picked phrases reveal more that you know how to Google, than you know basic biology. PBB, you seem to know a bit more, and you at least used comparative "easier," "stronger," which makes your comment confusing. Look, my post was about variance and overlapping curves between males and females, not about whether or not testosterone is implicated in a whole passel of human differences. It is. In fact, you two missed most of the interesting stuff. I didn't even bother with the vast literature on sex differences in neural architecture, for instance in medial temporal lobe development or the pre-optic area (SDN-POA). Or with the immune system; females, for example, have 1.8X higher levels of 5-lipoxygenase, thus produce more leukotrienes, which are a central component of inflammatory responses. Or with the trendy stuff on 2D:4D ratio, and whether it has anything to do with sexual orientation or aggressiveness. Or T's impact on myocardial remodeling. Or if you want to get beyond miscopied terms you've Googled ("augmentation neural activation adaptions (sic)" you might try a good review like Prog. Brain Res. 187:63 2010 on sex differences in prevalence of myosin heavy chain fiber types. (T also has a big impact on muscle leptin receptors, incidentally, which of course will impact cellular tradeoffs between glucose and beta-oxidation metabolism, and is probably a biggie for endurance sports. Blah blah; there are literally tens of thousands of scholarly articles about androgens and sex differences just since 2000, but so what?
Because at base, the issue isn't about Googling "testosterone," it's about being stuck in Father-Knows Best biology from the 1950's, in which something like testosterone creates a line in the sand between males and females. It's this magic stuff that only we males get to play with. If you think that, you just don't get it. You don't get that biologists no longer conceptualize sex differences, or biochemical differences, or racial differences, or species differences, as Rubicons that securely separate all of one kind from all of another. Biological boundaries, from organelles to species, are seen as permeable, dynamic, all about overlapping distributions in a sample and evolutionary dynamics. Your G.P. may like to confidently make a cut at the 5th or 95th percentile for your serum cholesterol, but that's an arbitrary convenience, not a reflection of nature.
Other hormones, and their receptors, and rates of conversion and production, impact the model. Variation in responses of receptor production means that females are a lot more sensitive to the androgens they do produce than we males are to testosterone. Which is why male body builders have to take such ridiculous doses to see results.
You also miss that the net biochemical pathways are about a lot more than plasma testosterone. For instance, women make about the same amount of androstenedione (McGuire's steroid of choice) as males, and some other precursors like DHA. Think of it as female adrenals taking over some of the workload that is accomplished by male Leydig cells.
So testosterone is an input variable, not an outcome variable. The outcome variables are things like Vonn's actual muscle biology in her vastus medialis. The force she can generate and the contractile time. Etc. These are determined by a large number of variables, not just testosterone.
I'll repeat the take aways from my other post: 1) Women also make testosterone, just less. And their bodies respond in a similar way; it's not like women don't have Type II fibers, or men don't have estrogen receptors. 2) It's an issue of proportion, not absolutes. What do male and female bodies have relatively more or less of? 3) It's the distribution of these proportions across two populations that's relevant, not the mean differences. Which is why they call it, "Analysis of Variance, and not "Analysis of means." Thus it isn't as simple as T sorts out the guys from the girls, thereby explaining why guys will always kick girls' asses.
At the end of the day, we honestly don't know where Vonn sits in terms of these interlocking pathways. A lot of stuff published in say J. Sports Med. and Med. Sci. Sports, and J. Strength Cond. indicates that females who excel at velocity/power movements have unusually high androgen levels. Moreover, as I cited previously, the sports themselves can induce androgen production. As can winning. So I deduce that if you could biopsy her, and do serial blood draws, and so on, that she'd be within the range of some male racers for those outcome variables that matter. Not most, probably.
Finally, you don't seem concerned with learned behavior. Biology isn't destiny. You're ignoring the most obvious fact about Vonn. She may just be better mechanically than many male WC racers. If a small flaw in how your body reacts to a rut or a bad neural reaction to a change in line will spell the differences between 1st and 20th, then it's reasonable to assume from her success on the women' circuit that she's got the mechanics down cold, maybe colder than some of the guys who could rely more on strength to get back on line. Unless, of course, you want to make the case that all racers are equally skilled, and the finishes are just about strength or blind luck. Good luck on that.