Instead of continuing to post about the differences between the anime and the manga in this thread,
I've decided to make
a Dragon Ball Super thread in the manga forum.
To be fair, I don't think you can accurately say WHAT their training entails, because you don't get to see very much of it. They were training with Whis for months and the anime only shows a couple of scenes of it.
They don't even show the first time Goku or Vegeta discover SSJ Blue. It's revealed during the Freeza fight after they'd already unlocked it. So you can't say for sure WHAT kind of training they were doing when they actually unlocked Blue for the first time.
You are the first person on the internet I've encountered that didn't think SSJ Blue was just activating SSJ and SSJ God at the same time.
The characters say it. The wikis say it. You're the only person I've seen who thinks it's just a metaphor used to describe the comparable power levels involved.