Board Thread:Theories and Speculation/@comment-26388300-20150523085628/@comment-26388300-20150529190322

I think you're right, GreatestSin. Then again, I'd also think it's not quite so much about Orochimaru having a weak body, but moreso the fact that he'd body-swapped so many times; I've always interpreted it that Orochimaru's inability to use senjutsu was a unique situation. I think most other shinobi, assuming they have proper chakra reserves, can train in senjutsu.

We literally see Tsunade lay a full-force punch directly to Orochimaru's face lol... and the dude got up. I don't think his body is weak, necessarily, I just don't think it's suited for senjutsu training due to his unnatural jutsu experiments.