Sir Chris Hoy, Britain's four-time Olympic track-cycling gold medallist, announced on Tuesday he was withdrawing from this month's World Championships in Poland because of injury.
Hoy, who has suffered complications following a hip injury sustained when falling off his bike in the keirin final of the Copenhagen leg of the World Cup in February, said: "I'm hugely disappointed that I'm not going to be riding in the Worlds."
The 32-year-old Scot, who won the sprint, keirin and team sprint events at last year's Beijing Games to set alongside his one kilometre time-trial gold medal from the 2004 Athens Olympics, added: "I've been really lucky in my career so far and this is the first time I've had to miss a major championship event due to injury.
"I'm glad it didn't happen this time last year and I'm still totally focused on being in the best shape possible for London 2012. This doesn't affect my long-term aim of defending my (Olympic) titles and I'll hopefully be back in training and competition in the near future.
"I wish the team the best of luck in Poland."
Hoy, the reigning keirin and sprint world champion, was also the favourite for the team sprint at the World Championships in Pruskow, Poland from March 25-29.
Although he did not break any bones during his Copenhagen fall, Hoy has been advised by medical staff to stop training and so give himself the best chance of making a full recovery.
"This type of injury is quite serious and pretty rare," said British Cycling team doctor Roger Palfreeman. "It's called a degloving injury and it's when the skin and the underlying tissue and fat get separated from the underlying muscle.
"The tissues are not bound down as they should be, which has created a space for fluid to collect in," Palfreeman added. "The fluid can be drained off, but every time Chris exercises or gets on his bike, the tissues are tearing again and the fluid's
coming back in to that space. He needs to give himself a decent amount of time to let the injury heal, which is why we've advised him not to compete in the Worlds."
© BikeRadar & AFP 2009