If he is moved above the line it means he has played 48 minutes or more that week. That doesn't necessarily mean he gets full training though as he may have played various positions that week. You need to play 48 minutes in the position or positions that you are training. If on the 'Manage your Team' page under 'Training' it lists the player with 48+ minutes that means he gets full training.
A player doesn't need 49 mins. 48 minutes and more is enough.
However, on the training page if it lists your player as 48 minutes and not 48+ minutes that means he has not played 48 minutes, he has played 47 minutes and a few seconds which has been rounded up and so that player needs to play a little bit more time to get full training.
Hope that helps!