Oh it goes without saying that the harder the team works and trains then it will tend to pick up more injuries, flip side is a team that works far too little will also pick up a lot more injuries, theirs a balance.
The thing with Klopp is though - he really front loads his preparation to try maximise the start to the season, with an absolutely intense pre season training schedule by all accounts, Koeman on the flip side seems to be the other end of the spectrum - one who seeks a very strong fitness later in the season (believe Martinez was also an advocate of that btw)
So with Klopp you have an intense style of play and training which going into the second half of the season is being demanded from players who've already ran a bit out of steam - and thats when injuries will start mounting up. Will try dig the post up i mad showing some of the main players at Dortmund mate, and the sheer number of injuries they received - and the fact a good few of them have effectively broken down to the point of being semi washed up in their late 20's