Antonio Conte has reportedly grown concerned that Chelsea's season is slowly unravelling and has therefore demanded even more from his players on the training ground.
The Blues have lost two of their last four Premier League games to open the door for Tottenham Hotspur to pounce at the top, seeing their advantage reduced from 10 points at the start of the month to just four.
According to The Sun, Conte has sparked into action by turning the club's Surrey training base into a boot camp in the hope of refocusing his charges for the end-of-season run-in.
Conte is said to have made his players train longer and harder in the build-up to Saturday's FA Cup semi-final showdown with Tottenham at Wembley, while also restricting the number of visitors to their Cobham HQ.
A source is quoted by the publication as saying: "Antonio realised some things needed to be changed to refocus the whole group on what is at stake.
"It's only for the run up to the Spurs match. After that it's back to normal. But basically, you can say the players are getting a kick up the backside."
Following this weekend's cup clash against Spurs, Chelsea face Southampton and Everton in quick succession in the Premier League.
Daniel Lewis
