The Sun's Manchester United correspondent reported that Pochettino will cancel Manchester United players' post-match rest days and strictly enforce team discipline.
Pochettino will also have his son, Sebastiano, by his side at Manchester United, who also served as his fitness coach for the United States national team.
Former Manchester United manager Michael Carrick did not have his own fitness expert, and Manchester United exposed problems of insufficient running and lack of match intensity in the 15 games he managed this season.
Manchester United ranked 19th in total distance covered, 17th in high-speed running distance, and 19th in average top speed in the Premier League this season.
Compared to the 17 games Carrick managed last season, Manchester United's high-speed running distance, sprint distance, number of sprints, high-speed running, and acceleration times all declined. They also ranked last in Gradient Sports' athleticism score.
When Carrick took over, Manchester United's fitness coach was Charlie Owen. He did not leave the team during this week's coaching staff reshuffle because he was not part of the behind-the-scenes team Carrick assembled in January.
Owen has served as Manchester United's fitness coach since Solskjaer promoted him in the summer of 2019.
The 40-year-old coach usually oversees player warm-ups at the start of Manchester United training, with players first engaging in ball work and running drills.
Solskjaer hoped to build a more physically fit Manchester United team, but in the first month after the start of the 2019-20 season, Luke Shaw, Anthony Martial, and Paul Pogba all suffered injuries and were out for long periods.
In the 7th round of the Premier League that season, in an away match against Newcastle United, six of Manchester United's starting eleven players were unavailable, and they eventually lost 1-0.
Manchester United's hierarchy has consistently defended Owen. His training sessions were approved by Erik ten Hag's former assistant, Mitchell van der Gaag, and were also popular with the players.
Erik ten Hag did not bring his own fitness coach when he took over in 2022. In his second season as manager, the 2023-24 season, Manchester United experienced 66 injuries or illnesses.
Several players felt Erik ten Hag's training intensity was too high. Amorim subsequently adjusted Manchester United's training schedule, gradually reducing the intensity of daily training as match day approached to ensure players remained in the best possible condition.
Amorim also brought Paulo Eduardo with him to Manchester United. He was Amorim's fitness coach at Sporting CP and later followed Amorim to Milan.
Mourinho and Louis van Gaal also brought their own fitness experts, namely Carlos Lalín, Stefano Rapetti, and Joost Van Dijk.
Pochettino will require Manchester United players to undergo recovery training at the Carrington training base the day after a match. Under Carrick, the team almost always had a day off after a game.
Erik ten Hag, Amorim, Mourinho, and Van Gaal all insisted on including post-match recovery days in their training schedules. This arrangement was changed in the later stages of Mourinho's tenure at Manchester United.
Former Tottenham defender Toby Alderweireld told the BBC: "First of all, he (Pochettino) got us physically very, very good. Pre-season was brutal.
"The way he wanted to play – aggressive, pressing high, high defensive line, playing with high intensity and a lot of energy – all demand that you have to run.
"You have to be able to run, to run with high intensity. The basis is good fitness.
"Every manager wants to have a good pre-season and also have time to convey their philosophy and physical demands to the players.
"But the players immediately feel that it's a completely different intensity."