WA's Winter Olympics medal hopes suffered a blow when the two-man bobsleigh carrying Perth teacher Duncan Pugh and pilot Jeremy Rolleston overturned, sending the pair hurtling to the finish line on their heads.

The duo lost control on the second of 16 bends on the Whistler track after Rolleston had difficulty getting seated because his foot got caught in the steering mechanism. They were disqualified.

"You have two bits of steering and my foot got stuck on one and that's why I stood back up, to get my footing," Rolleston said.

"At the same time we have two pieces of elastic. One of them broke. I had two freakish things happen. It was just devastating. It's important to say it's no one's fault, it's just a little bit perplexing."

Fortunately, neither was seriously injured in Saturday's spectacular crash, which came two days after Australia's other two-man team of Duncan Harvey and Darwin-born pilot Chris Spring crashed on the fifth turn during a training run and slid two-thirds of the way to the bottom.

Spring was not injured in the training mishap, but Harvey required CT scans and X-rays.

Anthony Ryan - a member of the Australian four-man bobsleigh team - took Harvey's place in the training runs, which the pair and Rolleston and Pugh completed without incident.

There has been unease among competitors about the safety of the Whistler Sliding Centre track since the death of Georgian luger Nodar Kumaritashvili, with US bobsleigh pilot and 2006 silver medallist Shauna Rohbock describing it as "stupid fast".

It would be a serious blow for Pugh to return empty-handed from Vancouver because he had said it would be his first and last Olympic attempt after he had dreamt of competing since childhood.

In December, he and Spring won a bronze medal at the 2009 America's Cup in Calgary.

The keen surfer, lifesaver and snowboarder took up bobsledding at 32 and practised by riding his sled on netball courts around Fremantle.

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