Well, I look more muscular than Alex, but I work out sometimes.
Alex doesn't go to the gym, otherwise people would see him there and someone would have been repported it here. Alex could not risk such a thing which would raise doubts on GP.
And his biceps are not flat simply because he is forcing them bending his arms, in that pic.
As Phelps says, he has low body fat and he is very fit, that's why he has good muscles.
And of course he is fit because he uses his inventions.
And as Gene says, he looks 20 in that pic.
Yes if he did not excercise his Biceps would be flat even if he is tensing his arms..
This is what i strongly believe for now..
ALEX can easily go to a GYM or any place he wishes, hes not that Famous yet Franco..