Liverpool stars put to the test by Jurgen Klopp as they undertake THREE gruelling training sessions in one day

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Liverpool's pre-season training went into overdrive on Friday as Jurgen Klopp put the likes of Mohamed Salah, Philippe Coutinho and Sadio Mane through their paces with three different training sessions.

As part of their training camp in Germany, the Liverpool stars completed a running session around the Rottach-Egern track amid a stunning backdrop of Bavarian forests.

It was only the first of three training sessions that will be completed as Klopp tests his players' fitness to their limits ahead of pre-season games against Hertha BSC, Bayern Munich and either Atletico Madrid or Napoli.

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Philippe Coutinho jogs alone as Liverpool complete the first of three training sessions

Daniel Sturridge, Sadio Mane and Jordan Henderson run in a line as part of training

Danny Ings (centre) looks on as he continues his recovery from a serious knee injury

Daniel Sturridge looked to be struggling with the early start on his Instagram account

Jon Flanagan posted a picture of Henderson struggling with the early start on Friday

Familiar faces like Danny Ings and Jordan Henderson were also in attendance with the Liverpool squad now back together following the summer break.

While new signing Salah looked in high spirits as he completed the early morning run, Daniel Sturridge and Henderson were evidently struggling to adapt.

Jon Flanagan posted a picture of the team captain dosing off on the team bus while Sturridge moaned about the early start during a video on Instagram before making it clear that he was not looking forward to the 'triple ripple' training day. 

Sturridge gets into gear as he shows off his agility by evading training poles in training

Mohamed Salah controls the ball as Coutinho watches on in a rainy second session

Divock Origi looks focussed as he completes a sprint drill in the second of three sessions

New signing Salah attempts to dispossess team-mate Alberto Moreno as a part of training

Spaniard Moreno shares a joke with his Brazilian team-mate Roberto Firmino

Mane shows his fun side as he shares a joke during the training session on Friday afternoon

Jurgen Klopp keeps a close eye on his players as he directs the training session in Germany

But Sturridge and Henderson will need to be alert if he is to force his way back into Klopp's first-team plans ahead of Saturday's friendly fixture against Bundesliga outfit Hertha Berlin, which will be played at the stunning Olympiastadion in the German capital.

Klopp admitted that he was still considering exactly who will play against Hertha, even suggesting he would opt against making the classic wholesale changes at half-time in favour of simulating a real match situation.

'If we will make 10 changes, I don't know actually,' Klopp told Liverpoolfc.com.

'We will make a match squad of 20 or 22 players, I'm not sure. [Friday] will be really intense and then we will see who we should take then. 

'We have real time, but we will sit together and then think about how we can line up, what kind of different things can we do and then we will wait for [Friday].'

The official photographer gets up close and personal with Senegal international Mane

Sturridge poses for the camera following the Liverpool training session in Rottach-Egern

Spirits appeared to be high despite the unprecedented gruelling Bavarian work-out that tested endurance levels to the hilt.

Mane, who earned critical acclaim from many inside and outside of the game for his excellent performances last term, was still going strong towards the end of a draining day - along with his energetic team-mates. 

The positivity Klopp's men showed towards the end of three intense work-outs - designed to aid the pressing style he insists on - was highlighted by Lallana and Ings sharing a joke at the end of a long day.

With the exercise guaranteed to help with Liverpool's stamina next season as they hunt for silverware on four fronts, the whole squad may be smiling when trophies are handed out next spring. 

Mane is prevented from powering through by and Ovie Ejaria during the third training session

Joel Matip climbs high as he and his team-mates have their stamina tested in the third session

Lallana and Ings still have the energy to share a joke despite three intense workouts in a day

Despite a trio of tough training sessions Henderson finds time to share a light-hearted appeal