A serious knee injury has put New Zealander Katherine Prumm's defence of her world women's motocross title in doubt.
The Pukekohe rider, 19, crashed in training in Belgium on Wednesday and has damaged her right knee.
The opening round of the five-round 2008 women's championship is in Bulgariaon Sunday.
The double women's World Cup winner landed awkwardly from a jump, feeling a tearing sensation as her right leg took the brunt of the bike landing on her.
An orthopaedic specialist confirmed she had ruptured her right anterior cruciate ligament.
She will require surgery, possibly total reconstruction of the knee joint, and the specialist had recommended she does not ride.
Her father, Erich Prumm, said from Sofia, Bulgaria that his daughter was determined to line-up on her Yamaha for the first grand prix.
"...she's a head-strong girl... she will see how she copes with the pain over the next 48 hours and take it from there.
"If she does ride, we will make sure she is well braced and strapped because her knee will be very unstable.
"She will ride practice at the GP and see if she can tolerate it. She says she's worked too hard for this to give up now."
Prumm's mother, Helen, said the outlook was grim.
"I have heard it might be a wet weekend, so that will be a problem for Katherine too.
"She's devastated. She has done so much hard training and said she has never felt so good on the bike as right now."
Prumm's build-up to her title defence had been progressing well before the setback.
Last weekend she mixed it with the men, racing against some of the world MX2 championship grand prix riders in the Flanders MX Trophy in Tongeren-Berg, Belgium .
She finished 16th overall after taking 15th and 16th in the two international MX2 motos.
New Zealand will have Manawatu's Nikki Scott in the women's championship, riding for the French-based Bud Racing team Kawasaki.
The other rounds of the world championships are in Italy (May 18), France (June 15), Germany (June 29) and the Netherlands (September 7).
