As well as spending countless hours honing in their skills on the training pitch, many professional footballers also undertake strict workout regimes in the hope of attaining optimum performance levels.
While some are content with merely hitting the club gym for an hour or two after training, others take their workouts to the next level in the hunt for every last marginal advantage.
Of course, all elite footballers are fit, but some are fitter than fit. Here's a look at some of the game's biggest gym fanatics, and the gruelling drills they put themselves through in order to hit their physical peak.
Each workout has also been examined by professional fitness expert Simon Brundish, sports scientist at Premier Injuries and founder of Strength:LAB.
Brundish has also provided a difficulty rating (out of 10) for each of the footballers' workouts, in terms of how a regular athletic person with correct form and execution would find them.
Of course, the ratings are subjective and results may vary greatly due to factors such as intensity and repetition.
Zlatan Ibrahimovic
Despite turning 40 later this year, Zlatan Ibrahimovic is still perfectly able to mix it at the top level as his record of 17 goals in 23 appearances for AC Milan so far this season duly attests.
The Swedish superstar employs a variety of workouts to keep himself in prime condition, including martial arts, planking and having his agent Mino Raiola stand on him.
However, perhaps the most punishing technique that Ibrahimovic uses is battle ropes, which involves throwing and manipulating thick heavy ropes in a ruthless burst of cardio.
The ropes, which can weigh anywhere between 25-50 pounds (12-22 kilograms), are tethered at one end and then "waved" by the player in a fixed stance using an array of workout patterns designed to prime the upper body muscles.
Expert rating: "The battle ropes are upper body conditioning mainly performed for show. As for Zlatan's other workout clips, the ball hops are great for proprioceptive ankle stability, and the core, pelvic and hip syncing work is great, but there's a layer of social media exhibition to it all."
Difficulty: 7.5/10
Cristiano Ronaldo
One look at Cristiano Ronaldo's Instagram is enough to show that a large portion of his life is devoted to working out, whether at home or at the training centre.
Indeed, Ronaldo's dedication to personal fitness is one of the principal reasons why the Juventus forward has been able to maintain elite standards for so many years.
During lockdown, the Portuguese was forced to improvise with his daily hill sprints, utilising his steep driveway to conduct short, explosive drills.
These brief but powerful runs help to build leg strength while conditioning muscle fibre and tissue using running-specific movement, which in turn aids with acceleration and endurance.
Just as with adding extra weight to a static workout, hill running uses gravity to increase the amount of force and power required to shift your bodyweight.
Ronaldo also uses an underwater treadmill for the same reason, with the extra resistance of the water forcing his muscles to work harder and therefore grow quicker, while also reducing load-bearing.
Expert rating: "Ronaldo is doing a great acceleration drill here, good for muscle firing, retaining maximum capacity and improving motor tendon unit efficiency. The underwater treadmill is also great for rehab on recovery days, taking the load of joints while still working the same neuromuscular pathways and energy systems."
Difficulty: 7/10
Erling Haaland
Ronaldo isn't the only top footballer who sustains his incredible fitness levels using hill sprints, with Erling Haaland also known to partake.
The Borussia Dortmund striker might have been on holiday at the time, but that didn't stop him from racing up and down inclines in the baking sunshine in an effort to maximise his stamina and speed.
We assume the "whoosh" sound effects were added later but given the speed Haaland was sprinting along the path, it's hard to be absolutely certain!
Expert rating: "Hill sprints rock, and are only beneficial to footballers -- though with Haaland's pale complexion I wouldn't recommend staying out in the heat too long!"
Difficulty: 8/10
Mohamed Salah
Mohamed Salah was photographed working out in the gym at the new Liverpool training centre this week, climbing a wall using nothing but his arms as teammate Thiago Alcantara looked on in awe.
With the Reds up against Real Madrid in the Champions League next week, it would appear Salah has been strengthening his upper body in preparation to face the Spanish giants again for the first time since the 2018 final.
The Egyptian was seen scaling a peg board at the AXA fitness centre, which helps to improve both bicep and grip strength while building lats, traps, shoulders, chest and core through sustained tension (holding your own bodyweight).
While standard weight lifting is all about regular repetitive lift patterns, the peg board can also improve hand-eye coordination due to the non-linear nature of the workout.
Expert rating: "This workout looks like good fun. It's also minimal risk and the benefits carry over to football well."
Difficulty: 7/10
Sergio Ramos
Salah isn't the only one running intensive fitness drills, as Ramos has also been sharing snippets of his own action-packed regime.
Sadly, we won't see Ramos and Salah go toe-to-toe for the first time since the final three years ago, when Salah suffered a shoulder injury in a tussle with Ramos. The Spain international suffered a calf muscle injury while on duty with his country and will miss the El Clasico clash with Barcelona and both legs against Liverpool.
The Real Madrid captain has been known to implement the "Mr T" workout at his home gym, which involves draping heavy chains around your neck much like the A-Team's finest.
Using steel chains to add extra pounds to standard workouts is a classic bodybuilding technique which is still widely used today, most notably favoured by Dwayne "The Rock" Johnson.
The heavy links add further load to drills such as dips, pull-ups, squats and bench presses with the fluctuating positioning and weight of the chain also helping to improve core stability.
Expert rating: "This certainly looks cool for Instagram, but it's quite foolish. Step-ups are a very important part of a footballers programme, but chains are only used to increase loading through the full range of movement.
"So they'd typically be on the ends of a barbell whilst squatting; the further away from the floor, the more chain is lifted off said floor, the more weight is being lifted."
Difficulty: 7.5/10
Robert Lewandowski
Robert Lewandowski is known as "The Body," and with good reason due to the 32-year-old Bayern Munich striker's taught and muscular physique.
The Poland international is famed for his abs, which he regularly trains using a variety of gym techniques, including a tough hanging core workout.
Hanging from a high bar, Lewy's full-body isolation exercise requires high levels of core strength while he rotates through leg raises, pelvic tilts, scissors and cycling.
The drill exercises the abdominal muscles and the hip flexors, as well as the core, the arms (grip in particular) and the lats.
Expert rating: "Put simply, this is a great, useable and high quality workout."
Difficulty: 8.5/10
Adama Traore
Adama Traore obviously puts in the hard yards when it comes to working out, with the Wolverhampton Wanderers winger completely transforming his body in recent years.
Strangely, Traore insists he's never lifted a single weight as part of his regime and instead packed on the muscular bulk by implementing intensive power training using fly-wheel exercise bikes and resistance bands.
As well as his blistering speed, the 25-year-old is capable of pulling off standing jumps that would make many NFL stars jealous.
Vertical box jumps are used to test athletes' energy transfer ability and explosive leg power; with NFL players commanding a broad average of around 40 inches (101 centimetres).
As can be seen in the photo above, Traore looks able to match that kind of height, much to the amazement of his Wolves' teammates.
Expert rating: "Box jumps are also used in all footballers' training. They develop power. But in this example, it's a competition at the end of a session. The point is normally to get one's hips as far off the ground as possible.
"The box jumps usually shared on social media are mostly for show, typically showing minimal hip movement, but rapid knee lift which allows the feet to land on a higher box."
Difficulty: 6/10 (or 9.5 to beat Traore!)
Neymar
In a bid to maximise his chances of outpacing defenders and evading challenges, Neymar regularly takes part in cable sprints at the PSG training complex.
A bungee cord is anchored at one end and then attached to the player's waist at the other, who then sprints away while simultaneously fighting the resistance of the elastic cable.
The bungee sprint is a form of resistance training designed to improve speed and agility, while also training the body to create speed reserves which can be called upon for one last surge of power during a high-intensity run.
Expert rating: "Resisted acceleration drills are great and very normal, as are the banded 'dead bugs' [lay on your back and lower/raise the opposing arm and leg] that Neymar is doing in the second photo."
Difficulty: 6/10
Nemanja Matic
Nemanja Matic is another footballer who caught the eye during the lockdown thanks to his gruelling approach to working out at home.
The Manchester United midfielder shared several clips of himself powering through an unorthodox crunch drill while laid over the bars of his treadmill.
While the merits of sit-ups are debated in the physical fitness community, the idea is to strengthen the core and improve flexibility, with Matic adding an extra layer of difficulty by climbing atop his apparatus to do so.
Expert rating: "Just more Instagram silliness, I'm afraid. No wonder Matic suffers with a bad back."
Difficulty: 7.5/10
Ansu Fati
As one of the most gifted and promising football talents on the planet, Ansu Fati also takes great care over his approach to fitness and conditioning.
The teenage Barcelona sensation posts regular dispatches from the gym on his social media channels, with his latest being a clip from a ball-based routine designed to aid his return from a knee injury. These balls strengthen everything in the lower body and core, especially ankles, so they're often used in injury recovery.
Barca have also shared a montage of Ansu's home training regime, which involves lifting weights to build muscle mass, assorted resistance work and drills atop a wobble pad to improve core strength, coordination, balance and stability.
Expert rating: "These home workouts are great for building core power whilst removing the load from Fati's injured leg. All good stuff."
Difficulty: 5/10
Virgil van Dijk
After injury ended his season prematurely, Virgil van Dijk has spent weeks grinding his way back to full fitness.
The Dutchman has been hitting the gym hard at Liverpool's new training complex, posting regular footage of his rehab workouts -- from weight training, to ball work, to golf, to yoga.
Among the more strenuous drills are the hip thrusts, which involve lifting and dipping the pelvis while pushing a 50kg barbell laid across the waist.
The idea is to work the legs and the glutes, as well as encourage optimal hip extension to add power and control to squats, deadlifts, sprints and vertical leaps.
Of course, Van Dijk manages to get through it all without breaking a sweat -- such is his effortless style.
Expert rating: "Impressive work at this point in Van Dijk's rehab, using limited range hip extension at relative low loads which will help build up capacity."
Difficulty: 6.5/10