Shanaze Reade and Liam Phillips both crashed out at the BMX World Championships in Birmingham on Saturday.
After each claimed silver medals in the time-trial in Friday's opening day of elite competition, Phillips was taken to hospital for scans on a shoulder injury after tumbling over his handlebars, while Reade suffered grazing after falling out of the super-cross Olympic discipline.
British Cycling later confirmed that Phillips suffered a broken collarbone.
Reade had serenely advanced to the quarter-final and appeared set to progress after a strong start only to tumble to the dirt while leading the field at the National Indoor Arena.
Four riders advanced and although the 23-year-old from Crewe remounted her bike swiftly and crossed the line ahead of three others who failed to finish after crashing behind her, she was ousted.
British Cycling BMX coach Grant White said: "She was going bloody fast into the first corner, tried to take a nice tight line and just slipped out - the traction just wasn't there.
"She was in a great mindset, really enjoying herself. She said after she fell off 'I'm not enjoying it anymore today'.
"I don't think anyone would enjoy going into the first corner at 50kph and sliding off on the tarmac.
"She's scuffed up, she's got skin off of everywhere and I think that's a reasonable comment to make in that position."
In 11 weeks' time Reade will be among the favourites for Olympic gold in London and she is set to spurn the opportunity for a week off next week to go into the gym.
She was in contention for a medal at the Beijing Games, only for a gold medal or bust move to fail.
Asked whether she might need to rein in her competitive instincts slightly, White added: "You can't ride reserved in our sport, it's just the way it is."
Abbie Taylor, who squeezed through qualifying to join Reade in the knockout rounds, was eliminated in the quarter-finals, while Tre Whyte and Grant Hill were knocked out in the qualifying round.
France's Magalie Pottier won the women's world title, with Australia's Sam Willoughby taking the men's title.
what do you think?
abbie taylor did not squeeze through! How is that exactly!!! 3rd overall in your motos is not squeezing through in elite women,maybe when your living in someones make believe shadow it is!