1) Low testosterone levels appear to be fairly common in hard training elite male athletes.
2) This may occur due to hard training itself, or to steroid use, or some other factor related to specific events. It is of interest that these researchers found no low values in basketball, canoeing, cross-country and alpine skiing and Olympic weightlifting athletes, but did find low values in powerlifters, soccer, swimming, rowing, judo, bandy, ice hockey, handball, and track and field.
3) "A very low testosterone level does not prevent an elite male athlete from competing in top events" and some researchers have "found no correlation between serum testosterone and performance in either men or women."
These latter observations are consistent with the observation by Carruthers that there appears to be no strong relationship between testosterone levels and symptoms of low androgen function:
Carruthers argues that the well-demonstrated disconnect between measured T levels and symptoms of T deficiency and the well-documented large individual variation in levels of T required to prevent deficiency symptoms provide evidence that men vary greatly in their tissue sensitivity to testosterone, such that those with high sensitivity have a lower apparent T requirement and those with low sensitivity have a higher apparent T requirement.
This combined with the finding of low testosterone in 25% of elite athletes suggests the possibility that some elite athletes may be elite in part because they have higher than normal sensitivity to testosterone. These men may get far more bang for each testosterone buck compared to the genetically typical male.
Carruthers concludes his paper with: