Josh Quigley said he came off his bike “pretty hard” whilst descending a hill at 35-40mph during training in Dubai this week.
Quigley, from Livingston, said he is not able to walk and is awaiting surgery on Thursday.
The crash came around 13 months after he was struck by a car in the United States during an attempt to cycle around the world in December 2019.
Last September, Quigley broke the record for cycling the North Coast 500 in Scotland.
He described his latest crash in a Facebook post, writing: “No cars involved, But I did come off the bike pretty hard whilst descending down a hill at about 35-40mph.
“Not sure the exact confirmed injuries yet but looking like I have multiple fractures. 3 on my pelvis, 2 on my shoulder/collarbone area, 1 on my elbow and 1 on my spine.
“Not able to walk and have any independent mobility and in a lot of pain. Not sure what the recovery process is looking like yet.
“But I’m having surgery tomorrow and then have two weeks of bed rest in hospital as can’t walk or move really due to back fractures and can only use my right hand side.”
He added: “Very grateful to Ben and Tobias who I was riding with for getting me an ambulance and making sure I got to hospital ok.
“There’s a great cycling community here who have been great to me since I’ve been here and they’re all doing a lot to make sure I am looked after and have what I need in here.
“Huge thanks also to a few people who stopped at the scene and all of the first responders and medical staff who have helped at the hospital so far.
“I’m a bit shaken up, but I’ll be alright.”
According to the World Record Academy website, Quigley completed the 516-mile North Coast 500 route in 31 hours and 17 minutes last September, setting a new record.
In the crash in 2019, Quigley was airlifted to hospital after being launched off his bike and landing 50 feet away while cycling in Texas, suffering multiple fractured bones.