Dutchman also pledges to continue fielding young players in first team

Sources say players have responded well to Van Gaal's methods

Van Gaal's hopes repetitive drills will improve players when on the ball

Rooney, Van Persie and the rest of the United squad were pictured lifting weights on Thursday ahead of their Old Trafford meeting with Everton

Only players and essential staff allowed on Carrington pitches when the first team are

Manchester United's stars are being worked harder in training than ever before by new manager Louis van Gaal, club insiders have revealed... and here is the evidence.

Such is Van Gaal's ferocious desire to fast track the players he inherited from David Moyes on to the levels he desires that Wayne Rooney, Robin van Persie, Juan Mata and Co are being driven relentlessly by the Dutch coach on a daily basis.

And the United squad were pictured being put through their paces on Thursday, in scenes reminiscent of a pre-season training camp.

Louis van Gaal keeps a watch on Wayne Rooney and Michael Carrick as they're put through their paces

Rooney and his strike partner Robin van Persie are pictured lifting weights at United's Carrington HQ

Van Persie leads his team-mate through a set of leg exercises designed to improve their core fitness

Radamel Falcao, who arrived from Monaco on deadline day, lifts weights at United's training headquarters

Rooney, Van Persie and new signing Radamel Falcao were among those lifting weights and taking part in numerous training drills ahead of their home clash against Everton on Sunday.

Chief among Van Gaal's methods as he tries to bring about fundamental change at Old Trafford are incessant passing drills that see the United players put through endless repetitive routines aimed at honing and developing new instincts.

Van Gaal has spoken of how he wishes his players to think differently and react differently when they are in possession. By putting them through these endless drills, he hopes they will use the ball better and will eventually make better decisions without even seeming to think.

The new United manager has also shown himself to be a lover of double training sessions. Van Gaal asked his squad to train twice-a-day regularly on pre-season tour of America as he sought to change his players' thoughts and instincts quickly.

That practice has continued to an extent, though, now that the Barclays Premier League season has started and it's not unusual for players to train late in the morning, rest in the sleep unit that was installed last year at Carrington and then train again in the afternoon.

'It can seem relentless but the players understand why Louis is doing it,' said a club source earlier this week.

Darren Fletcher and Van Persie appear to show the strain of the new training sessions at Carrington

Van Gaal chats with United vice-captain Darren Fletcher ahead of their weekend clash against Everton

Louis van Gaal was spotted leaving the Lowry Hotel in Manchester on Tuesday morning

Van Gaal seemed to be looking for the right space as he prepared to leave the Lowry Hotel

Manchester United's players have also been playing full-paced 11 v 11 games in training prior to games

Van Persie (right, with Radamel Falcao) has praised the methods of Van Gaal

Manchester United's players have often been sleeping at Carrington between double training sessions

'The passing drills are incredible. It's just "pass, pass, pass" until the manager and his coaches think the players are beginning to do it almost naturally and instinctively.'

Van Persie – who played under van Gaal for two years for the Dutch national team – said on Wednesday that some of the United manager's sessions are 'incredible', with players having to be focused during 'every single minute'.

It is also understood that another of Van Gaal's policies is to play full-sided 11 v 11 games for 45 minutes two days before a game.

This game is required to be of the intensity of a Premier League game and is aimed at preparing the players mentally and physically for the competitive game that is due to follow 48 hours later.

Wayne Rooney (left, with coach Marcel Bout) and his United team-mates are said to be pleased with training

Luke Shaw (left) and Falcao are two new signings adapting to Louis van Gaal's training methods

It is not unusual for managers to play full-sided games in training as it allows the weekend's anticipated first team the opportunity to get used to each other and grow familiarity. However, they are usually played at half or three-quarter pace and full-on contact is minimal as managers are generally paranoid about injuries.

What has struck the United players about Van Gaal's 45 minute games, though, has been the intensity. To play these games at full pace is rare but Van Gaal insists on it so that his players are 'match ready' when the actual competitive fixture comes around two days later.

During his time in England – and indeed during the World Cup – Van Gaal has shown himself to be surprisingly open about injuries and fitness issues. Most managers like to hide problems from the public so as to keep the opposition guessing and will sometimes exaggerate minor knocks to fool rivals in to thinking star players aren't available.

Van Gaal doesn't do this but the former Barcelona and Bayern Munich coach is obsessively secretive about his team shapes and training drills to the extent that he will only allow players and staff absolutely vital to the session anywhere near the Carrington pitches when the first team are working.

Other Carrington staff are asked to stay away so that Van Gaal can go about his business in private before players are handed individual dvds and dossiers of their training performances to watch later with United's performance staff and even at home in their spare time.

Wayne Rooney drives into training despite the fact he is suspended for the clash with old club Everton

Robin van Persie looks focused as he prepares to continue his goalscoring run

United's £60m signing Angel di Maria shows off his shiny studs as he motors in

Marouane Fellaini (left) is another who will be playing against his old club and he drives in with his brother

Paddy McNair made his debut for Manchester United against West Ham last Saturday

Paddy McNair (left) is one of several young players Louis van Gaal has promoted to United's first team