When Louis van Gaal was a talented midfielder of just 17, he had to make a choice that would define his entire life.

Making the Ajax first team that at the time boasted the likes of Johan Cruyff and Johan Neeskens or follow his family's wish and train to be a PE teacher.

Van Gaal being Van Gaal, he decided to do both. Enrolling at the Academy of Physical Education to attain his coaching qualifications, he simultaneously trained with Ajax - and he looked every inch the PE teacher when putting his Manchester United squad through their paces in America.



VIDEO Scroll down to watch Luis van Gaal supervising Manchester United training



Tied up: Manchester United's players had elastic bands attached to their waists for some resistance training

Uncompromising: Louis van Gaal keeps a close eye on the performance of his Manchester United players as they took part in a circuit training session ahead of their International Champions Cup final against Liverpool

No slacking: The Dutch manager watches on as the players are put through their paces in Miami



Push up: Van Gaal makes a point as the players perform one-handed press-ups using basketballs

Test of strength: Striker Javier Hernandez gets to grips with the weights during the training session. The Mexican scored United's third goal in their 3-1 win over Real Madrid on Saturday

Strongman: Wayne Rooney takes his turn to lift the weights as pre-season training continues apace

Barking the orders: Van Gaal watches on as his assistant Albert Stuivenberg issues instructions

Hard work, lads? The players certainly looked as if they'd been put through a hard session



The Sun Life Stadium in Miami resembled a 'Boot Camp' as the players were put through a gruelling session of circuit training.



A stopwatch and a whistle round his neck, van Gaal wore an unrelenting critical glare as his players sprinted and slalomed through cones, lifted weights and medicine balls, and took part in resistance training with an elasticated band around their waists.

The scrutiny was intense. Nobody was allowed to slacken off for a second. If they did, he would issue a stern rebuke or send assistant Albert Stuivenburg to do it for him.

When the players were granted a pause in the sticky Florida evening they looked knackered.

VIDEO Van Gaal demands a lot - Fletcher

Ambitious: A young van Gaal (circled) lines up for amateur side SV De Meer. He harboured dreams of playing for Ajax but also continued with his studies to become a PE teacher from the age of 17

Good start: United have won all four matches under van Gaal's stewardship so far, against the LA Galaxy, Roma, Inter Milan and Real Madrid

Stung: New signing Luke Shaw was publicly criticised by van Gaal for not being fit enough

Best foot forward: Goalkeeper Sam Johnstone at the end of a rope held by Shinji Kagawa

Hold on: Keepers Sam Johnstone (left), Anders Lindegaard (middle) and David de Gea take part in the resistance training part of the circuit

Roll with it: The players also used medicine balls and barbells during the circuit

Weighed down: Javier Hernandez smiles as he carries a weight

VIDEO Van Gaal happy with squad

It has become clear on United's American tour that van Gaal is not only trying to instil a new tactical awareness in his players but also make them the fittest and strongest in the Premier League.

He had no problem with publicly embarrassing new signing Luke Shaw by saying he wasn't fit enough and made him train on his own to catch up. It doesn't matter if you're the new £31m signing.



Even striker Robin van Persie, the 'teacher's pet', has been told to prove his fitness before being allowed anywhere near the team.

Instructions are short and sharp, delivered in an authoritative tone. He's not looking for a discussion, this is what's going to happen.

His biographer Maarten Meijer captures this 'schoolmasterly' approach well in his recent book.

Slalom: Sam Johnstone steps through the cones as Kagawa waits for his turn behind

Quick step: Kagawa, who set up Hernandez's goal against Real, gets his feet moving

Jog on: Wayne Rooney and Tom Cleverley take part in the warm-up

Return: Darren Fletcher is enjoying his first pre-season in two years following struggles with illness

Get moving: The players size up the circuit as training gets underway in Miami



In form: Ashley Young has scored four times on the American tour as he bids for a first team spot

Thoughtful: Assistant manager Ryan Giggs watches on as the squad train

'The experience of daily interacting with often unmotivated or emotionally troubled youths at school has given these trainers a cutting edge,' he writes.

'This skills can be recognised in the way they deal with their adult charges - pro players - who can be just as testy and demanding as high school boys, and who intermittently require patient understanding and tough discipline.

'Van Gaal's critics are perturbed by what they consider the coach's schoolmasterly style and tone.

'In their view he is still the high school teacher: ever the smart-aleck, autocratic, comfortably convinced of the superiority of his own opinions, and no one should dare to criticise master van Gaal's methodology.'

Van Gaal has always refuted these PE teacher comparisons but, watching him stood, hands planted on hips with an unchanging, unimpressed expression, as his United players are sent round the circuit, it's hard to believe him.