They have been rarely trained except for 3 players in my team who were power-trained this season (where only 1 between them was injured during a match, and 2 injuries occurred during the training). All the other players that were injured were not due to bad condition or training. They were used the way I normally used players in the previous seasons, and they were not even overplayed as I used a squad rotation system.
When you will be in the same situation, then you will know what I have talked about. The injuries keep coming from nowhere without any logical explanation apart from intentionally caused by Nordeus, bad programming or bugs in the game. This is why I have posted in the bugs section. The way things have gone, it is unlikely that this may be normal because far too many injuries have occurred for a short period of time.