...die erhöhung des serumtestosterons ist erstens minimal (zu gering für eine hypertrophe rekation, dafür bräuchte man eine erhöhung mit der 200fachen amplitude, im vergleich zu den hier gemessenen werten)
Dazu eine Frage: Wie erklärt es sich, dass der Bluttestosteronspiegel auch innerhalb physiologischer Grenzen sehr gut mit Muskel- und Kraftentwicklung korreliert und nach wie vor folgendes in der Fachliteratur diskutiert wird...

Eur J Appl Physiol (2003) 89: 555-563:
In conclusion, the present study suggest that serum basal testosterone concentrations and acute increases in serum testosterone concentrations due to a single resistance exercise session may be important factors for training-induced muscle hypertrophy as well as for strength development of the trained muscles.
Med Sci Sports Exerc. 2004 Apr;36(4):674-688:
Exercises stressing multiple or large muscle groups have shown the greatest acute metabolic responses (9).
For example, exercises such as the squat, leg press, leg extension, and bent-over row have been shown to elicit greater rates of oxygen consumption than exercises such as the behind-the-neck shoulder press, bench press, upright row, and arm curl (9). In addition, these exercises have elicited the greatest acute hormonal responses (67).
Deadlifts (25), squat jumps (105), and Olympic lifts (67) have produced greater acute 22-kDa growth hormone and testosterone responses compared with exercises such as the bench press and seated shoulder press. Thus, the amount of muscle mass involved in a movement significantly impacts the acute metabolic demands and anabolic hormonal response, which have direct implications for resistance training programs targeting improvements in local muscle endurance, lean body mass, and reductions in body fat.
Übrigens: Die obige Studie sagt zwar nichts über die Möglichkeit eines "spillover effects" aus, kommt aber - wenn ich das richtig verstehe - dennoch zu dem Schluss, dass die durch das Training ausgelösten Androgenwirkungen eine Rolle beim Muskelaufbau spielen:
In regard to AR signaling, muscle hypertrophy induced by electrical stimulation in rodents administered an AR antagonist (16) seems to suggest that the androgen-AR signaling pathway has a significant effect in exercise-induced muscle hypertrophy and emphasizes the importance of the AR in exercised muscle.
...und hier:
Specifically, we demonstrated that both total and free TST (by order of the FAI) levels are subject to increases in response to individual sequential bouts of heavy lower-body resistance exercise. In addition, the
mRNA and protein expression of the AR were significantly up-regulated after the second and third exercise bouts, respectively, correlated to serum TST, and corresponded to significant increases in myofibrillar protein by the third exercise bout. Therefore, we conclude that three sequential bouts of lower-body heavy resistance exercise to be effective in up-regulating AR expression, likely by way of a pretranslational mechanism that may be contingent on increases in free TST. Furthermore, the increased AR expression may have increased myofibrillar protein content by way of the androgen-AR signaling pathway.
Mal abgesehen davon, dass Testosteron ja scheinbar auch Auswirkungen auf die lokale IGF-Produktion hat.

...und eine Anmerkung:
und zweitens wird sie durch eine erhöhung des SHBG-levels ausgeglichen.
...offenbar falsch! Ich zitiere aus obiger Studie:
The increased TST observed following resistance exercise is typically not associated with significant changes in SHBG levels...
...sowie:
A significant Group x Test interaction was observed for serum TST (P = 0.001). However, no significant differences were located for SHBG (P > 0.05).

Gruß