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