Why are so many players obsessed with knee-slide celebrations?

It's the flamboyant goal celebration many players love, despite the inherent risk of serious injury or embarrassment. The knee slide.

Bruno Fernandes became the latest Premier League star to perform it at Old Trafford on Sunday after scoring an outrageous goal for Manchester United from the centre-circle in a 2-2 draw with Liverpool.

Racing away towards the corner flag, Fernandes left two tramlines in the pristine turf as he slid for several yards on his knees and then got back to his feet in one smooth motion. Eight out of 10.

A day earlier, Newcastle's Bruno Guimaraes appeared to jar his right knee as he attempted and failed to slide, leaping up with what appeared to be a grimace toward the joyous travelling support after scoring in a 1-0 win at Fulham. Four out of ten. Must try harder. Or, might be a better idea, don't try it at all. Ouch.

But why do players do it? When did it start? And is it really advisable for multi-million footballers to be jeopardising their knee joints in this way?

Like kids who can't resist skidding on a patch of ice, the temptation seems to be too much - particularly when the finely manicured pitches have been heavily watered or drenched by rain, as was the case at Old Trafford.

'I just can't control myself,' Liverpool's new signing Marko Grujic said in 2016 after knee sliding to celebrate a goal for Jurgen Klopp's side on his debut against, er, Fleetwood Town.

In November, Manchester City cheekily posted a video montage on social media with the message 'every City knee slide at Old Trafford this season', showing Erling Haaland, Phil Foden, Lauren Hemp, Phil Foden and Khadija Shaw celebrating their goals against United.

It even has its own science. When Lewis Hall scored in Newcastle's Carabao Cup win over United at Old Trafford in November, his slide was measured at an impressive 8.71 yards.

Meanwhile, on local pitches all around the country every weekend, young boys and girls are whizzing around on their knees in homage to their heroes.

Jairzinho is credited with pioneering the celebration in the 1970 World Cup final after scoring Brazil's third goal in a 4-1 win over Italy at the Azteca Stadium in Mexico, although look at the footage and he sinks to his knees in prayer rather than attempting to gain any distance.

Still, back in the 70s it would have been unwise for an English player to slide on any pitch except Wembley. The surfaces were so heavy, you would have struggled to cut through them with a tractor never mind a pair of knees.

Indeed, it's hard to imagine groundsmen these days being overjoyed at seeing their precious turf carved up in such a needless way.

The peculiar practice didn't really take off until the 1990s when pitches improved dramatically and perhaps players felt more inclined to perform for the cameras at the advent of the new Premier League.

Thierry Henry was so accomplished at the celebration that his statue at the Emirates immortalises the Frenchman on his knees, head bowed and fists clenched by his sides after scoring a sensational goal for Arsenal in the north London derby at Tottenham in 2002.

Former Arsenal man, Emmanuel Adebayor, almost started a riot at the Etihad seven years later when he raced the length of the field to slide in front of the away fans after scoring for Manchester City.

Who can forget Didier Drogba's celebration after heading a late equaliser for Chelsea against Bayern Munich in the 2012 Champions League final or Ole Gunnar Solskjaer's following his winner against the Germans in 1999?

Many years later, Solskjaer confirmed that he 'tweaked' his medial ligament when he slid on the Nou Camp pitch but denied rumours it triggered the knee problems that ended his career.

And that's the danger. In a moment of euphoria, players risk hurting themselves by going over the top.

'It's a risk and a needless risk,' says former Liverpool and Bolton physio Mark Leather.

'You can't guarantee the surface of the grass is consistent all over the pitch and you're going to glide across it. The problem you get sometimes is the soil underneath is harder and the grass is a bit firmer. Do you trust it?

'If the friction increases and there's a lack of give in the grass, that's the risk of causing a potentially serious knee injury.

'It's great to see players celebrating goals with whatever they do, and it's difficult because it's part of the enjoyment of the game for the fans seeing some passion and celebration.

'But that particular movement is not a good thing to do for your knee. It's just a silly position to put your knee into. It never goes into that position ever, kneeling fully at pace across the turf.

'It's only a matter of time before sadly someone is going to really hurt themselves and, particularly at the professional level, that could be a costly celebration.

'Some clubs might frown on players doing it for those reasons. Why don't you think of another celebration other than that?

'They've obviously pre-planned a lot of this because that's their celebration. Some don't, some of are off the cuff. But if you're planning it, you probably need to think twice.

'I worked with a couple of managers that probably wouldn't like it, Sam Allardyce and Neil Lennon, because they know the value of the players to them.

'I don't think it would go down particularly well doing that. They would have relied on the senior group of players to advise that we can't afford anybody to be out of action for needless goal celebrations.'

Patrick Vieira missed five weeks of Arsenal's Double season in 1997-98 after damaging knee ligaments celebrating a goal in a win over United, and Alphonso Davies was hurt celebrating his first ever goal for Bayern Munich. Southampton's Carlos Alcaraz, Sandro of OPR and Real Betis' Sergio Garcia all came a cropper.

Eden Hazard stopped knee sliding at Chelsea in 2018 because his knees were 'on fire' after celebrating 22 of his 96 goals to date that way.

Earlier this season, Hibernian's Martin Boyle hurt himself only to have the double whammy of seeing his goal against Aberdeen ruled out by VAR.

'I might have to tell him to change his celebration – or wait six minutes before he does a knee-slide!' joked manager Nick Montgomery.

Then there are the face planters, those players whose only injury is a bruised ego when it goes wrong and they pitch forward into the turf.

Tottenham's Rafael van der Vaart embarrassed himself in one once such incident, and Romelu Lukaku banned himself from knee sliding at Chelsea in 2021 after another against Aston Villa.

Reading manager Kevin Dillon once told Kevin Doyle to cut out knee sliding. 'I wouldn't mind a somersault because he's in more control,' said Dillon.

Sometimes the managers are just as guilty themselves, even though they're wearing a suit and are old enough to know better.

Think Real Madrid boss Jose Mourinho against Manchester City in 2012 or Paolo Di Canio when Sunderland won the Tyne-Wear derby away to Newcastle the following year.

They're all at it and it doesn't feel like football's favourite celebration will be on the slide anytime soon.