CHICAGO (AFP) - The executive leadership of USA Gymnastics' board of directors has resigned in the wake of the sexual abuse scandal involving former US team doctor Larry Nassar, the governing body announced on Monday (Jan 22).

Chairman Paul Parilla, vice-chairman Jay Binder and treasurer Bitsy Kelley stepped down following stinging criticism of the organisation's handling of the Nassar case by victims who include Olympic superstar Simone Biles and other gold medallists.

"We support their decisions to resign at this time," said Kerry Perry, who was named president of USA Gymnastics in November.

"We believe this step will allow us to more effectively move forward in implementing change within our organisation." USA Gymnastics has come under fire during the ongoing sentencing hearing for Nassar in Michigan, in which more than 100 gymnasts have given statements against the disgraced former doctor, who faces life in prison for his offences.

The board of directors will name interim chairpersons until permanent selections are made as the beleaguered body tries to advance beyond the scandal.

In a statement on the USA Gymnastics website, Perry thanked the departing trio of leaders "for their many years of service to this organisation". "As the board identifies its next chair and fills the vacant board positions, we remain focused on working every day to ensure that our culture, policies and actions reflect our commitment to those we serve." .

Victims fury in testimony

Perry replaced Steve Penny, who had resigned last March after 12 years in the post after criticism over how USA Gymnastics had handled the sexual abuse claims.

"Several people did speak up. Why didn't anyone listen or care enough to do anything?" asked Paula Daniels, whose daughter Samantha was identified as a victim of Nassar's abuse.

Nassar, 54, has pleaded guilty to 10 counts of criminal sexual conduct and faces life in prison. He has already been sentenced to 60 years in prison after pleading guilty to child pornography charges.

At his sentencing hearing in Michigan, more victims spoke on Monday, including Taylor Livingston, who talked about the guilt she felt concealing the abuse from her father, who died last year.

"When you die, you're going to hell," she told Nassar. "But there will be a pit stop on the way where you'll have to face my dad, who now knows what you've done... and when you do, you will suffer." Lead prosecutor Angela Povilaitis said 144 people were set to give victim impact statements and another two dozen speakers were planned, most testifying to the profound toll the abuse has taken on their lives and families.

Life is a constant fight

The hearing's fifth day also featured Livingston, who was 13 at her first appointment with Nassar in 2009, saying she suffered from constant depression and anxiety.

"Life is a chore," she said. "Life is a constant fight." Nassar's victims, according to prosecutors and civil attorneys, include his former family babysitter and athletes in several women's sports programmes at Michigan State University, where he worked.

The Karolyi Ranch, a suburban Houston layout once famed as a breeding ground of champions, will no longer serve as a training site for top gymnasts, USA Gymnastics announced last week, the facility holding too many horrific memories for too many US athletes.

Biles, who dazzled in winning gold at the 2016 Rio Olympics, said in her Twitter post last week revealing abuse by Nassar at the ranch that it "breaks my heart" to think of returning there to train for the 2020 Tokyo Olympics.

Olympic gold medalist Aly Raisman said continued use of the ranch as a national team center would be more evidence of indifference by USA Gymnastics.

USA Gymnastics also came under attack after it emerged that Olympic gold medalist McKayla Maroney had been required to sign a gag order preventing her from talking about the abuse under the terms of a US$1.25 million (S$1.65 million) settlement agreed in 2016.

USA Gymnastics later waived the order last week following criticism, saying Maroney would be free to discuss the abuse without fear of financial penalty.