Jul 28th, 2019

Jul 28th, 2019

Shayna Jack has revealed the heartbreaking moment she found out she had tested positive to banned substance "Ligandrol".

According to ASADA's website, Ligandrol, also known as LGD-4033, is "claimed to be a substance that induces muscle (and bone) growth without the side effects associated with steroid use".

News of Jack's positive test shook the swimming world on Saturday, in a week where controversy surrounding doping in the sport had been at a high, following the Sun Yang saga.

In the statement, Jack explained how she struggled to breathe following the phone call with an ASADA representative.

Despite being found with an illegal substance in her system, Jack has vowed to fight (Getty)

"I felt my heart break instantaneously," she wrote.

"I couldn't breathe to answer her next couple of questions. There was nothing I could do at that moment, nothing the people around me could do to help me.

"I was in complete shock, asking myself how and why is this happening to me.

"My brain repeated over and over: 'I have always checked my substances', 'I didn't do this', 'why is this happening to me?', 'I've done nothing wrong'."

Despite her 'B' sample coming up positive for the banned substance, the 20-year-old has vowed to fight to prove her innocence.

Jack positive drugs test 'heartbreaking'

"Reminding myself of why I swim and why I want to be in the Australian team is what has kept me fighting," she said.

"The day I found out was the day I began my fight to prove my innocence.

"Myself, along with my lawyer, management team, doctor and family have been working continuously to not only prove my innocence but to try to find out how this substance has come into contact with me, to ensure it doesn't happen to anyone else, as I wouldn't wish this experience on my worst enemy."

Jack also detailed the mental struggles she has endured since receiving the devastating news, saying every day has been a "rollercoaster".

"Some days I am okay and others I am not," she wrote.

Gold Medalist Shayna Jack, with team mates Bronte Campbell, Emma McKeon, Cate Campbell (AAP)

"This will be an ongoing challenge, not only with trying to prove my innocence to ensure I can get back to training for the dream I have had since I was a little girl, but also the challenge of facing judgement from people who don't know me; people who will just assume the worst."

Swimming Australia has been castigated for not having an official address the media at the world championships on Saturday once the story broke.

"I do accept the criticism that we did not have an official speak poolside last night and that Cate Campbell spoke on behalf of our team. That was my call," said Swimming Australia CEO Leigh Russell.

"In retrospect we could have done that differently but I do want to acknowledge Kate and her leadership and our team."