Actually, Senkuu's Atlas & Axis were of stone and Tsukasa wanted to tear them and applied the sufficient force to do it, therefore Senkuu fainted because of the strength to do so, but needed more to actually tear the stone, implying that Tsukasa can break stones.When they are "unpetrified", their bodies are restored and there are traces that they were once stones. Since Senkuu's neck had stone on it, unpetrifying his neck restored the broken bones and everything.
Please, no more friendship bullshit on second arc D:
This manga may survive? Jajaja, Boichi and Riichirou are like having Arakawa or Mashima drawing on WSJ, all the editors will try to make it popular even if the public doesn't want it. Boichi's art is wonderful, to my eyes.