Canada's Nic Hamilton has been ruled out of the Commonwealth Games after suffering a concussion in training.
The 27-year-old was hurt when colliding with an official inside the velodrome in Glasgow on Wednesday, and will now be forced to be out of action for at least a week.
"He would have been travelling at 55 to 60 kilometres an hour," Canada's performance manager Kris Westwood told reporters. "It broke his frame, and destroyed his helmet. So his helmet did the job it was supposed to do.
"Nic came around the banking and just saw her too late and hit her and crashed. He got a concussion, and he's banged up and bruised."
The official is reported to have been concussed and broke her collarbone in the collision.