That's a very valid point, & I think @Treble is working on the assumption that all footballers are equal with respects to workrate, commitment, & desire to win. You see some highly paid players walk off the pitch after 90 minutes without an ounce of sweat on them, & then you get others who are soaked to the skin in sweat because of the amount of effort they put in. Klopp has now got a bunch of players who fit into the 2nd category. Lads who'll run & run, & then run through brick walls if need be. I bet if stats were available for distance covered by United players under Ferguson's glory years then we'd see them pretty near to the top of that particular table. It never did them any harm in respect to winning major honours.What do you base this argument on? Your gut feeling?
Anyone with any experience with running would tell you that the match program for a premier league footballer is very much sustainable if they are relatively fit. Of course you have lazier players who won't cope, but they don't represent everyone.