Marcelo Bielsa is a coach who has earned a reputation as a master tactician and his school of thought regarding the game of football has many students, most notably Pep Guardiola.
However, while Bielsa's philosophy and meticulous nature have been lauded at teams across three continents, his methods have not necessarily yielded the results he would have hoped to have achieved.
The Argentine, who has been tasked with returning Leeds United to the Premier League, has a relatively bare trophy cabinet, enjoying limited success with Newell's, Argentina and Velez.
Bielsa has lost a Copa America final, a Copa Libertadores final, the Europa League final and the Copa del Rey final, not to mention the surprise of missing out on promotion in his maiden season with Leeds.
Exactly why the Rosario native - nicknamed El Loco - has not managed to collect more silverware remains a mystery to many, but one of the most popular theories is 'Bielsa burnout'.
What is 'Bielsa burnout'?
'Bielsa burnout' is the name given to a theory which posits that teams coached by Marcelo Bielsa have a tendency to suffer from fatigue in the final third of a season.
That fatigue, it is argued, arises due to the intensity of the Argentine coach's preferred style of play, which places serious physical demands on players.
Bielsa's philosophy dictates that his teams relentlessly press the opposition in order to win the ball back as early as possible.
"My football in defence is very simple: 'we run all the time'," Bielsa is quoted as saying in Inverting the Pyramid .
In training, players are extensively drilled, which is understood to be extremely demanding too, with the decidedly ominous term 'murderball' being used to describe a particular exercise.
“It’s basically playing 11 v 11 with no stops,” Leeds midfielder Mateusz Klich told Leeds Live of the infamous 'murderball' drill.
“Constantly running around and sprinting, and you have all the coaches on the pitch basically screaming all the time and basically you can’t stop running.
“It’s just a normal game with normal rules, 11 v 11 on a big pitch. You just play, but you can’t stop running. It’s tough, but it’s the most important session in the week.
"It depends on the training how long he wants us to play. It could be five times six minutes, or one times 20 minutes. It just depends what Marcelo wants.
“Even if the ball goes out, there’s a member of staff waiting with another ball to put it in. You can’t stop.”
The term 'Bielsa burnout' has been popularised by football media, with many of Bielsa's critics pointing to similar trends occurring at a number of Bielsa's former clubs.
Is 'Bielsa burnout' a real thing?
It is difficult to say for sure whether 'Bielsa burnout' is a real phenomenon or not, but anecdotal evidence suggests that it is something that is genuinely felt by players.
For example, striker Fernando Llorente played under Bielsa at Athletic Club from 2011 until 2013 and reportedly worked so hard under the Argentine during the 2011-12 campaign that it effectively scuppered his chances of playing at Euro 2012. That said, Llorente was not exactly first choice for La Roja anyway, with Cesc Fabregas and Fernando Torres both ahead of him in the pecking order.
Former Manchester United midfielder Ander Herrera played alongside Llorente in that Athletic Club team and he has spoken of an inability to run at the end of the season.
Despite a scintillating run to the Europa League final in 2012, Athletic ultimately lost against Diego Simeone's Atletico Madrid and they were beaten in the Copa del Rey final that season too - albeit by Pep Guardiola's Barcelona.
Herrera, though, insists that he does not blame Bielsa, who he says was "amazing" in his role.
"No-one was able to run as much as us, it was impossible," Herrera said on the Big Interview with Graham Hunter in 2018, reflecting on his time working with Bielsa. "But I can't lie to you, in the last months we couldn't even move. Our legs said 'stop'.
"We used to play always with the same players and were not at our best in the finals. We were a completely different team than we had been before because, to be honest, we were physically f*cked. We couldn't run any more.
"I am not blaming the manager, because he was amazing for us and we should be very thankful because of the beautiful football, but the last month we could not even move and that is the reality."
Bielsa, unsurprisingly, has consistently denied the charge that his tactical approach is somehow self-defeating.
Towards the end of Leeds United's unsuccessful promotion drive in 2018-19, for example, he simply laughed off the suggestion, telling a reporter: "It’s clear you don’t know what you’re talking about, because if there’s something this team doesn’t lack, it’s energy."
However, despite Bielsa's dismissal of the notion, the facts certainly illustrate a decline in the second half of the season, which saw them miss out on automatic promotion and then fall short in the play-offs.
Leeds suffered a total of 13 defeats in the Championship regular season in 2018-19, with 10 of those coming from the end of December until the conclusion of the campaign.
From December 29 until May 5, they endured 10 defeats in 22 league games, before being well beaten in the play-off semi-final by Derby County.
However, while some of Bielsa's teams have apparently been victims of burnout, others have enjoyed success, a fact which seems to contradict the theory. He steered Newell's Old Boys to glory in the early 1990s and did so again with Velez in the late 1990s, for example.
Perhaps, then, the likelihood of 'Bielsa burnout' being 'real' comes down to a question of will - of a commitment to push one's body to and beyond what is deemed physically possible. Some will be able to maintain the level demanded of them and some won't.