US Olympic team doctor sentenced to 175 years in prison

US Olympic gymnastics team doctor Larry Nassar has been sentenced to at least 175 years for the sexual abuse of more than 150 victims.

The disgraced long-time team doctor, Larry Nassar, apologised to his victims on Wednesday ahead of his sentencing for molesting young female gymnasts but a judge dismissed his words as insincere.

Following days of testimony from more than 160 of his victims, Nassar stood before the court in a dark blue jailhouse jumpsuit and addressed the dozens of women in the Michigan courtroom.

"Your words have had a significant emotional effect to myself and shaken me to my core ... an acceptable apology to all of you is impossible to write or say," he said.

"I will carry your words with me for the rest of my days."

Judge Rosemarie Aquilina responded by reading aloud portions of a letter Nassar wrote her after his guilty plea, saying that his victims had "fabricated" allegations to gain money and fame. He said his actions were medical, not sexual, in nature.

"This letter tells me you still do not own what you did," Aquilina said.

"I wouldn't send my dogs to you, sir."

Courtroom spectators gasped when the judge read a part of the letter in which Nassar said he was "manipulated" into pleading guilty by prosecutors' threat of a trial.

The prosecution has asked for a sentence of 40 to 125 years for Nassar, who is already serving a 60-year sentence in federal prison on child pornography convictions.

More than 160 of Nassar's victims - including Olympic gold medalists - spoke at his sentencing hearing in Ingham County Circuit Court in Lansing, Michigan.

The last victim to testify on Wednesday, Rachael Denhollander, was the first to come forward publicly with allegations against Nassar. She reported him to Michigan State University police in 2016 and told her story to the Indianapolis Star.

She testified that Nassar began abusing her in 2000 when she was a 15-year-old gymnast.

"As we were being sexually violated, Larry was sexually aroused by our humiliation," Denhollander said.

Aquilina, who has expressed support for the victims, told Denhollander she had "started the tidal wave."

"You are the bravest person I have ever had in my courtroom," the judge said.

Nassar pleaded guilty in November to seven counts of first-degree sex assault in Ingham County and previously apologized in court for his crimes. As part of a deal with Michigan authorities, he also pleaded guilty to three additional counts in Eaton County and will be sentenced there next week.

The accusers had testified Nassar won their trust with kind words and by giving them snacks forbidden by their coaches.

Testimony came McKayla Maroney, a gold medalist at the 2012 London Olympics, who called Nassar a "monster human being" and a former member of the US national team who said his abuse led to depression and an eating disorder.

Another gymnast blamed Nassar for her father's suicide once the man realized his daughter had not been lying about the abuse she endured.

Nassar, 54, served as the USA Gymnastics physician through four Olympic Games. He also was the team physician for the Michigan State University gymnastics and women's crew teams, as well as an associate professor at MSU's College of Osteopathic Medicine.

Victims and others have criticized USA Gymnastics for ignoring their complaints and have accused the federation of suppressing their accounts in a bid to avoid bad publicity.

On Monday, three top board members resigned in wake of the scandal and continued criticism, following the exit last March of the federation's president and chief executive.