I believe at some point, think I read it on the old forum, the codes were changed regarding injuries, to stop over training in an attempt to rush a players progress.
I'm guessing they have been tweaked again at the start of this season.
If they tweaked these below periodically then it's safe to assume all are.
IMO this
Top Eleven Football Manager - Forum • Login was one of the reasons the old forum is now on it's death bed.
This only shows a few of the nasties lurking inside the game engines head.