Rio Shock: Cyclist's high-speed crash 10km from Olympic Gold [video]

Dutch cyclist Annemiek van Vleuten lay helpless in intensive care after suffering three cracked vertebrae in a stomach-churning high-speed crash while leading the Olympic women's road race.

The 33-year-old was 10km from Olympic gold when she tumbled over her handlebars and crashed into on a concrete curb on tricky descent that some have said was too dangerous for the Games.

Van Vleuten was left in a motionless heap on the side of the road as other stunned competitors raced by.

Annemiek van Vleuten, of the Netherlands, leads Mara Abbott, of the United States, during the women's cycling road race at the 2016 Summer Olympics in Rio de Janeiro, Brazil, Sunday, Aug. 7, 2016. (Pool Photo via AP)

She was expected to spend at least 24 hours in intensive care in a Rio hospital before doctors decide the next steps.

The Dutch Cycling Federation initially said she was conscious and had been taken to hospital.

"Heavy concussion and three small fractures in her lumbar spine. She continues 24 hours in i.c. (intensive care)," the federation said on Twitter.

The federation added that she was "conscious and speaking".

The Netherlands' Annemiek Vanuatu Vleuten and Ellen van Dijk gesture from the start line as they get ready to compete in the women's road race near Fort Copacabana during the Summer Olympics in Rio de Janeiro, Brazil, Sunday, Aug. 7, 2016. (Pool Photo via AP)

Images of the crash made for uncomfortable viewing as Van Vleuten was left sprawled on the side of the road when victory in the 137km race seemed within her grasp.

Dutch team-mate Anna van der Breggen won the race but spoke of her shock at riding past her stricken team-mate and then deciding to take on the race leaders.

"It really shook me when I saw Annemiek crashed in the road," said the new champion.

"Annemiek was leading but I realised I was now first in the team so I had to chase. I did it also for Annemiek."

Sweden's Emma Johansson took second and also spoke of her concern for Van Vleuten.

"Annemiek's crash was horrendous. We just want to know she is OK," she said.

The crash happened on the Vista Chinesa, the same descent where the leaders of the men's race were wiped out on Saturday.

Italy's Vincenzo Nibali suffered a broken collarbone and Colombia's Sergio Henao broke his pelvis. The season is now over for both men.

Australia's Richie Porte broke a shoulder blade on the same section of the course during the penultimate descent on Saturday.

There has been widespread criticism of the road.

"It is an absolutely incredibly dangerous course," said Britain's Olympic champion Victoria Pendleton.

Chris Boardman, the 1992 Olympic champion, also condemned the course as "dangerous".

But cycling's governing body, the UCI, insisted great care had been taken for the race.

"The Rio 2016 road race course was carefully designed and was extensively tested at the test event and in training," the governing body said in a statement.

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