"It's obvious that it's too much, absolutely obvious," Jurgen Klopp said in 2019.

"Everybody involved in the game will tell you that, and you know it as well."

He said it as Liverpool were at the peak of their powers, top of the Premier League, Champions League winners and with the Club World Cup firmly in their sights.

In between their quest for glory on the international stage in Qatar for the first time in their history, within that was a Carabao Cup quarter-final as well as trip to the King Power Stadium to play Leicester City.

Klopp, the Premier League and the English Football League (EFL) were embroiled in a game of brinkmanship as the Reds threatened to pull out of the League Cup.

In the end, Neil Critchley was forced to field his U23s side for their last eight match against Aston Villa, with an average age of 19 years, six months and three days.

Irrespective of the result, what the German manager said was right and two years on still rings true but the latest figures from CIES illustrate the risk of burnout as a result of too many matches.

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Steven Alzate scored the only goal as Brighton and Hove Albion returned to the south coast with all three points, adding further to the misery of Liverpool 's opening months of 2021.

After the defeat, Jurgen Klopp highlighted his side's fatigue: "We haven't had a break, I think City had a two-week break for COVID reasons.

"It's really tough. It's a tough season for many teams.

"It's the first time I felt that way, but after a week of twice travelling to London, two intense games [against Tottenham and West Ham], I don't think we really ran too much in those games. We ran exactly as much as we had to do to win the games.

"Then we came back and faced a Brighton team who had a good idea and we were not ready at that moment, obviously.

"The players couldn't do it and you have to think why they couldn't, that's why I said what I said after the game.

"But we now have four days between games, things are different. Last week we had two days between games and travel, that's not an excuse, that's just how it is and we, therefore, weren't fresh enough."

With Project Restart and the latest Premier League season held in quick succession with fixtures being played out at least twice a week, the injuries compiled, especially in Liverpool's case.

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Injuries to the likes of Joel Matip, Jordan Henderson and Joe Gomez saw them succumb to the treatment table for an extended period. Henderson's coming during the 2-0 Merseyside derby defeat to Everton when early in the first half a burst beyond the half-way line before wincing in pain before going to ground holding his thigh.

Surgery soon followed for the Liverpool captain and his season was over.

Trent Alexander-Arnold recently fell victim to injury on international duty with England as they prepared for Euro 2020.

The right-back limped off late on in their first warm-up match against Austria and was ruled out of the tournament, he now faces a race to be fit in time for the start of the Premier League season.

Figures published by the CIES Football Observatory Weekly Post emphasise the number of minutes and lack of break players had over the past year.

Andy Robertson ranked the fifth highest outfield player to play the most minutes, accumulating 6,022 minutes in 69 games for club and country. Only Bruno Fernandes, Harry Maguire, Ruben Dias and Jules Kounde ranked higher.

However, the Scotland captain ran up over 6,000 minutes of football in fewer games than all of those above him. It begs no surprise that he trudged off during Liverpool's 4-1 defeat to eventual Premier League winners Manchester City.

Kasper Schmeichel, Hugo Lloris, Manuel Neuer and Thibaut Courtois all ranked amongst the highest number of minutes played due to their position.

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Further down the list, Georginio Wijnaldum playing time amounted to 5,549 minutes in 73 games for the Reds and the Netherlands. Last season, the 30-year-old started in 89% of Liverpool's Premier League matches and played in every match as they secured third place on the final day with a win over Crystal Palace.

Depending on how far the Liverpool contingent at the European Championships progress, if they make it to they will have just 34 days to rest, recuperate and prepare for next season as the Premier League kicks off on the weekend commencing August 14.

Nevertheless, as Robertson embarks on a momentous journey as the captain of Scotland, manager Jurgen Klopp will be keeping a close eye on Liverpool's key man.