Australian BMX star Sam Willoughby remains without feeling below his chest after a serious training crash which left him with spinal damage.

The family of the world champion and Olympic silver medallist has released more details of the serious injuries he suffered on September 10 in an American training crash.

“At this stage, Sam still has no movement from his chest down but has regained use of his arms and is slowly regaining some sensation in his legs,” Willoughby’s family said in a statement released by Cycling Australia.

“Sam’s next step is to begin a long road of recovery at a rehabilitation centre and, while the details are still to be finalised, at this stage, it is expected that Sam will be transported to a US-based rehabilitation centre in the next few days.”

Willoughby crashed at his local track in Chula Vista, near San Diego, and was airlifted to hospital.

He suffered fractures to his C6 and C7 vertebrae, severely compressing his spinal cord and leaving him with no movement below the chest.

Willoughby underwent surgery, with the C6 vertabrae removed and replaced by a titanium cage.

His C5 and C7 vertebrae were also fused with a plate and four screws.

“Fortunately, this surgery was successful enough at decompressing his spinal cord and aligning his vertebrae that a second operation for further stabilisation was not necessary,” the family added.

Australian BMX rider Sam Willoughby will move to a rehab centre within days. Photo: Road2recovery

The family added the support for Willoughby has been incredible and they had set up a web portal where people could provide financial support and leave messages.

Willoughby won silver in BMX at the 2012 Olympics and made the final in Rio, but finished a surprise sixth.

He also is a two-time world champion.

His American fiancee Alise Post won BMX silver in Rio.

Post and Willoughby’s parents, Colin and Sharon, provided the statement about Willoughby’s injuries.

-AAP