Manchester United boss Erik ten Hag had his players undergo long range running drills on Sunday after their dismal defeat at Brentford.
Ten Hag is the first United manager in over a century to lose his first two games. United, the 20-time champions of England, sank to the bottom of the Premier League table.
The Dutchman punished his team for running a total of eight-and-a-half miles less than Brentford by making them cover the same distance on Sunday, reports the Daily Mail.
Cristiano Ronaldo's attitude is also concerning for Ten Hag and his coaching staff.
Ronaldo is said to be training well, he exchanged words with Ten Hag's No 2 Steve McClaren at the final whistle after refusing to applaud United's travelling fans, and there is a feeling that his mood is having a negative effect on the dressing room.
However, United have dismissed suggestions that Ronaldo's contract could be cancelled, and reiterated that he is staying at the club.