IShowSpeed Quits Backflip Record Attempt At 660, 'I Can't Move Anymore!'

IShowSpeed fell short in his attempt to beat the backflip world record, quitting after an astounding 660 flips Tuesday night ... after the (super athletic) streamer said he could no longer move!

But, Speed's vowed to try again soon!

The 19-year-old began his attempt Tuesday morning, attempting to break the world record for backward somersaults, set by Nico Scheicher in 2019. NS completed 1,001 in 24 hours.

Of course, Speed did it live with many of his millions of followers watching along, cheering on the streamer as he attempted to topple the record.

We won't show you the whole stream (it went on for 19 hours!!!!) ... but after 600 backflips, Speed, despite the encouragement of his friends, just couldn't continue.

Speed's body gave out.

"I can't move anymore," Speed said, "There's nothing I can do about that."

FYI, the good people at Guinness World Records weren't aware Speed was attempting to break the record until the day before, and because of that, they didn't have an adjudicator on site. But, that doesn't mean the record wouldn't have counted ... the GWR people told us they'd review Speed's footage if he had topped the 1,001 mark.

Speed, known for his energy and wild stunts (like jumping over speeding hypercars), said his next effort will be in a month or two.