There were thrills, spills and a major ache for American rider Brooke Crain as Australia’s Caroline Buchanan sped through tonight’s BMX time trial faster than her rivals.

Buchanan, the world no.2, completed her seeding run in 38.434sec to finish 0.21sec in front of New Zealand’s Sarah Walker. Bunbury rider Lauren Reynolds was ninth fastest in 40.045sec.

Today’s racing against the clock was to determine the make-up of Friday’s semifinals and it was mostly incident-free.

But Crain was left dazed and winded after a high-speed crash when she horribly mistimed a jump.

The incident immediately brought back bad memories for the American team, who lost Arielle Martin from their Games line-up after a horror training smash in July.

Martin was rushed to hospital with life-threatening injuries including a lacerated liver and collapsed lung. She has had three operations and is now recovering.

Thankfully for Crain, who replaced Martin in the Olympic team, her crash was not serious and she dusted herself down and limped over the line. She is expected to compete in Friday’s semifinals in which the top four riders in each race will advance to the gold medal race.

Crain’s teammate, Alise Post, said crashes were part and parcel of the sport and a rider’s ability to immediately look beyond an incident was crucial.

“Part of what we do is taking spills here and there thankfully I think she’s going to be all right with that one,” Post said.

“You really need to screw your head on straight and just be able to focus on yourself out there because there’s going to be a day when you’re up on the gate and things happen like that right in the race in front of you.”

In men’s seeding, Latvia’s Edzus Treimanis also felt the full force of gravity when he ploughed into a jump and fell from his bike.

Dutchman Raymon van der Biezen was fastest qualifier in 37.779sec. Australia’s world no.1 Sam Willoughby was sixth fastest, posting 38.496sec. WA’s Khalen Young was 17th and South Australian Brian Kirkham was 22nd.

Men’s racing continues tomorrow with quarterfinals. The first four riders in each of the four races will progress to the semifinals.