Canberra's Caroline Buchanan was forced to withdraw due to injury from this week's UCI BMX World Championships being staged at the Adelaide Showgrounds in South Australia.
"I've never had a big injury and never had to miss out on a race before so it's pretty disappointing," said Buchanan.
The 18-year-old reigning Australian Champion injured her back during training last month in Austria and, whilst she is recovering well, doctors have advised her to pull out of the Championships and concentrate on her recovery.
"I was training starts on an old BMX gate and it didn't drop when it should have," said Buchanan. "I kept going though and did a scorpion faceplant over the gate and hyperextended my legs over my head.
"It wasn't too bad at the time and I didn't feel much pain," said Buchanan who soon after raced and won the four cross event at the Maribor round of the UCI Mountain Bike World Cup in Slovenia. "Apparently that, and the long flight back to Australia, did more damage to my back so I got an MRI done when I got home, and it showed a tear in a disc in my lumbar region."
Buchanan had originally hoped to recover in time for this weekend's racing but doctors warned against rushing back into competition.
"All the doctors said this sort of injury needs to heal so if I had trained too early and pushed it at any time it could tear more or bulge and then it would a really long recovery time," she said. "The doctors said six weeks and this weekend is five weeks, and I've been really 'babying' it along, not lifting anything, not bending, not sitting on the couch, sleeping on my side and doing lots of physio work to get it right.
"It would have been great to race in front of a home crowd with everyone there to support me but my focus is now on preparing for the Supercross Series with the first round on next month in South Africa," said Buchanan. "It has been pretty difficult getting back into it but everytime I complete a new exercise and there's no pain, I get a little more confidence back.
"I wish the Australian team all the best for this week," she said. "I have been speaking to them and they all seem really well prepared."
Rachel Bracken and Lauren Reynolds are competing in Buchanan's absence. Buchanan will have another chance to compete in the World Championships at home - this time the mountain bike worlds in Canberra, Australia, scheduled for early September.