Last updated on .From the section Gymnastics

Mary Bono was appointed on Friday after Kerry Perry, who was criticised for her handling of the fallout from the Larry Nassar abuse scandal, resigned in September

The interim boss of USA Gymnastics has resigned after her appointment was questioned by Olympic champions Simone Biles and Aly Raisman.

Mary Bono was criticised after appearing to oppose Nike's advertising campaign with Colin Kaepernick.

She was appointed as interim president and chief executive on Friday.

"My withdrawal comes in the wake of personal attacks that, left undefended, would have made leading USAG a liability," Bono said.

Bono, 56, had also previously worked for a law firm which represented USA Gymnastics and its ex-team doctor Larry Nassar during a sex abuse scandal.

Nassar has been sentenced to more than 300 years in jail for abusing gymnasts.

His victims included 2016 Olympic gold medallists Raisman and Biles.

In a statement confirming her resignation, Bono claimed she had seen "assaulting behaviour" by a coach when she was a young gymnast.

"It is with profound regret, coupled with a deep love for the sport of gymnastics and respect for those who aspire to be great gymnasts, that I today tendered my resignation," Bono said.

"I would have brought a fire in the belly to ensure that no-one as taken with gymnastics as I was at that age, should have to choose between abuse and ambition, or between properly speaking out and promoting personal success."

Simone Biles (right) criticised Bono's tweet, which has now been deleted

What did she say about Kaepernick?

Biles criticised Bono for tweeting apparent opposition to sportswear company Nike making NFL star Kaepernick the face of its new advertising campaign.

In 2016, Kaepernick protested against racial injustice by kneeling during the US national anthem, a gesture which has proved controversial in the country and drew criticism from President Donald Trump.

Bono had tweeted a picture of herself colouring in the Nike logo on her golf shoe.

"With respect to Mr Kaepernick, he nationally exercised his first amendment right to kneel. I chose mine," said Bono.

She said it was an "emotional reaction" while at a tournament for families who have lost members of the armed forces - including her brother-in-law, who she said died while serving as a US Navy Seal.

Alongside a picture of Kaepernick, Nike's advertising campaign used the phrase "Believe in something. Even if it means sacrificing everything".

Bono said members of the armed forces who died while serving had "literally sacrificed everything", adding: "I regret that at the time I didn't clarify my feelings.

"That one tweet has now been made the litmus test of my reputation over almost two decades of public service."

Why was Bono criticised by Raisman?

Raisman, who won team and floor gold at London 2012 and team gold at the 2016 Rio Games, said it was the former congresswoman's role at Faegre Baker Daniels that troubled her.

In a series of tweets, she pointed out how lawyers at the firm, although not Bono herself, and sport administrators had been aware of abuse allegations against Nassar in 2015, and yet he had been allowed to continue working - and abusing children.

Nassar was sentenced to 60 years in prison on child pornography charges in December and received up to 175 years in jail on sexual abuse charges in January. He then received a further 40 to 125 years in February for molesting young gymnasts.

Bono's predecessor at USA Gymnastics, Kerry Perry, resigned in September just nine months after taking up her role, having been criticised for her handling of the fallout from the Nassar scandal.

Bono worked on legislative strategies and policies for the firm and was not involved in the Nassar case.

Bono said she "proudly stands behind her body of work" at Faegre Baker Daniels.

USA Gymnastics said accepting Bono's resignation was "in the best interest of the organisation", but that the decision was taken "despite her commitment to the sport of gymnastics and helping the organisation move forward".

"We remain steadfast in our efforts to fundamentally transform the organisation at all levels to ensure athlete safety and well-being is at the heart of everything we do," it added.

The USAG statement continued: "While we have made progress, we have much more work to do."