Dr.'s Feigenbaum and Baraki (or any others with the relevant background),
For 46XY persons with Complete Androgen Insensitivity Syndrome (CAIS), what is known about changes in their hip width and lean body mass during puberty, particularly compared to typical males and females? Does this substantively change for individuals with Partial AIS (PAIS)? “Typical” is not meant to be normative here, just numerically descriptive.
I want to clarify my understanding of what CAIS means for adults:
As Jordan and Austin have repeatedly stated (if I am misinterpreting either of you, please correct me), part of the reason why the “normal” male range for Testosterone is so wide (300-1000 ng/dL) is individuals with higher T-concentrations tend to be less sensitive to it, and visa versa. This is also why (to a first approximation) T-levels are not particularly predictive of sports performance: concentration and sensitivity tend to be inversely correlated. Only T-levels below the normal threshold (even here there is nuance), and greater than normal levels due to exogenous T ingestion, are associated with performance detriment and increase, respectively.
So, CAIS individuals have T-levels that may be near or within the “normal” male ranges, but this has no direct implications for sports performance since they are completely insensitive to it. Is this correct?
Put another way, an individual with CAIS could ingest exogenous T and gain no associated performance benefits.
-And again, do the answers substantively change for PAIS individuals?
I am not interested in stirring any political debates, but I cannot find sources that adequately address these specific questions.
If this topic should be posted elsewhere, my apologies.
It varies significantly between individuals, so much so that nearly all outcomes are possible without more information. In other words, whether complete or partial, musculoskeletal development can be “normal” or wildly different than predicted norms.
I think there is more to it, though T level relationship to performance. In healthy men and women, higher total T levels don’t necessarily correlate to sensitivity systemically, as tissue-level sensitivity and overall response is dynamic based on other, non-T factors. This is why given a wide range of total T levels, T-related outcomes are the same. Yes, hypogonadal can reduce performance (but not always) and supraphysiological T levels can increase a number of potentially desirable outcomes (but not always).
Regarding androgen insensitivity syndrome, again, there are wide range of presentations here. We don’t have a robust evidence base for those with the condition and performance in sport, unfortunately. In individuals without known androgen insensitivity syndrome, T levels do not predict performance in sport. A few other conditions (in women) that can result in higher-than-normal T levels (like PCOS) are overrepresented in sport, but still, T levels don’t seem to correlate with performance here either.
I have no knowledge of using exogenous T in those with androgen insensitivity syndrome.
I think focusing on testosterone levels in sport is mostly in error.
A few other conditions (in women) that can result in higher-than-normal T levels (like PCOS) are overrepresented in sport
Are there any working hypotheses on why they are over represented given that the T levels themselves aren’t particularly predictive of sport performance?
Lots of theories out there with varying levels of plausibility. The one that I “like” the most has to do with an increased potential for earlier physical development in these individuals, leading to a sporting advantage early on. This compounds over time with greater opportunities for coaching, sports participation, support, and so on. I think we just get a snapshot of what’s contributing to performance in sport in adulthood.
That’s interesting. I know Malcolm Gladwell catches some flak for his methods and conclusions, but I think he wrote about a similar “accumulative advantage” effect of physical development (related to age cutoffs of sports rather than true biologically early development).