'I am learning': HYROX athlete apologises and withdraws after viral defecation incident

The Australian athlete at the centre of the HYROX defecation controversy has apologised and retroactively withdrawn from the race after footage of the incident went viral internationally.

Social media footage showed Australian athlete Joanna Wietrzyk, who holds the women's HYROX solo pro world record, competing at exercise stations with faeces on her legs during a race in Beijing over the weekend.

In a statement posted to Instagram on Thursday night, Wietrzyk apologised for her decision to continue competing.

"I want to offer my sincere apology to the people of China, my fellow competitors, the spectators and the HYROX organizers for what happened during the race in Beijing," she wrote.

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"I felt completely fit and healthy at the start of the race, with no reason to expect any illness. Looking back, I regret the decision to not have stepped off the track.

"I recognize that I should have made a different choice. I take responsibility for my decision to continue and am deeply sorry for the discomfort and disruption it caused."

Wietrzyk also announced that she would forfeit the points she earned as the competition winner.

"I am learning from this experience and will carry those lessons with me, including remembering that there is more to life than racing and knowing when it is right to step away," she said.

"On reflection, I have decided to retroactively withdraw from the race and forfeit the points I earned."

Ending her statement, Wietrzyk said: "Thank you to those standing by me, both as an athlete and as a person, during this time, and to everyone who has reached out with kindness and support."

"It means more to me than I can properly express right now. I will be taking some time to recover, reflect and look after myself and my family away from the noise."

HYROX is a fitness and endurance race that combines 8km of running with exercises such as rowing, sled pushes and wall balls, carried out in indoor exhibition halls.

Wietrzyk initially shared a selfie after the race on her Instagram story, which showed her lying down with an intravenous line in her arm. It was captioned: "Go hard or or go home they say ... a win is a win".