Australia's Genevieve Gregson ruptured an Achilles tendon in the women's 3,000 metres steeplechase final at the Tokyo Olympics.
Gregson sustained the injury when she fell coming off the final water jump and was unable to finish the race.
She needed assistance from medical officials at the National Stadium and left the track in much distress with the use of a wheelchair.
"Horrible news for three-time Olympian Gen Gregson after rupturing her Achilles tendon in the women's 3000m steeplechase final," Athletics Australia tweeted.
"Our thoughts are with her and we wish her a speedy recovery."
Uganda's Peruth Chemutai won gold in a time of 9 minutes and 1.45 seconds, with Courtney Frerichs (9:04.79) of the United States claiming silver and Kenyan Hyvin Kiyeng (9:05.39) picking up bronze.
Gregson, who was competing on her 32nd birthday, was well off the pace when she sustained the injury.
Wednesday night's race was her third appearance in an Olympic final.
Gregson was ninth in the 3,000m steeplechase final at the 2016 Olympics in Rio, where she also placed 12th in the 5,000m decider.
She made her Olympic debut at the 2012 London Games, but did not advance from the 3,000m steeplechase heats.
