It's 48+ - it doesn't matter if the guy played more than 48 minutes. Once he reached 48 minutes (at trained positions) he is going to get a full training.
It is hard to tell how big deal is to have full training. Because not all respectable,average, etc, are not the same. You just see a number (a word actually) but there are decimals so respectable can be anything from 6.5 to 7.4 /<6.5;7,5) interval. So you can't tell how close to pop this or that player is.
Example: I had a player popped after receiving a training for just 18 minutes last week during the bug. Of course he popped in a rerun with increased minutes too.