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 Monday.

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

"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 organization."

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.

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

It's a step the US Olympic Committee (USOC) has been seeking for months, USOC president Scott Blackmun said in a statement stressing the need to focus on the victimized women.

"New board leadership is necessary because the current leaders have been focused on establishing that they did nothing wrong," Blackmun said.

"USA Gymnastics needs to focus on supporting the brave survivors. The Olympic family failed these athletes and we must continue to take every step necessary to ensure this never happens again."

- Victims fury in testimony -

USA Gymnastics president Perry replaced Steve Penny, who resigned last March after 12 years in the post following criticism of how USA Gymnastics handled the 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 day five of his sentencing hearing Monday in Michigan, more victims spoke, including Taylor Livingston, who called life a "chore" and "constant fight" due to 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 the last of 144 people were set to give victim impact statements before sentencing Tuesday or Wednesday, most testifying to the profound toll the abuse took on their lives and families.

- 'The last child...' -

Emma Ann Miller, the youngest to speak at 15, described Nassar's actions in a supply closet during a 2016 medical appointment at a clinic she said is still trying to bill her family for the appointment.

"I'm possibly the last child you will ever assault," Miller told Nassar, saying she plans to keep going while Nassar "fades into a federal prison cell."

Nassar's victims, according to prosecutors and civil attorneys, include his former family babysitter and athletes in several women's sports programs 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 training there for the 2020 Tokyo Olympics.

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 $1.25 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.