Cook must be a great actor because that pain looked genuine.

I think he has a bad back, he has some kind of degenerative problem which he probably has good and bad days with out of the ring. From the interview he did, he said it isn't getting better or worse, but will always be around.

I expect he did his training camp and got through it mostly fine, certainly expected to be able to do 12 rounds and then the back would hurt the next day. But in the fight, the back just went. Partially due to the punch, partly due to the way he twisted.

I think it was just one of those things that just so happened to happen in the fight. I genuinely don't think it was a fix or his back was THAT bad going into the fight.