Hmmmm, I wonder, do trolls necessarily have strong "bones". I mean, they are kind of gangly/sinewy. Could it be that their core is a weaker type of cartilage and they rely more on muscle working against other muscle. I don't even know if that's possible... but it made me think.
Hmmm... that train of thought made me just realize that trolls HAVE TO have a normal two-sex anatomy, and it also has to be fairly similar to the 'human norm', because trolls CAN mate with other creatures (giants in particular - apparently they all had the same mother... or father... or were cousins... something like that...)
Hmmmm, the whole idea of troll sex.... given that they can try whatever twisted thing they want to do and regenerate from it.... OMG, I think I just vomited a little bit.