Nassar pleaded guilty to molesting female athletes under the guise of medical treatment and was sentenced this year to life in prison.
"He told me he was going to do a check-up on me and that was the first day I was abused,” Maroney, 22, told Guthrie. “He said that nobody would understand this and the sacrifice that it takes to get to the Olympics, so you can't tell people this."
“He didn’t say it in a way that was mean or anything like that," Maroney added. "I actually was like, ‘That makes sense. I don't want to tell anybody about this’. And I didn't believe that they would understand.”
In an interview with NBC news programme Dateline airing on Sunday, Maroney opens up about the years of abuse by Nassar.
Bela and Martha Karolyi, the former USA Gymnastics national team coordinators, will also speak for the first time about the sex abuse scandal.
Authorities say Nassar victimized more than 260 women, including several of Maroney's Olympic team mates.
Nearly 200 of them offered testimony during two sentencing hearings in Michigan this year.
The scandal prompted the entire board of directors at USA Gymnastics, the sport’s governing body in the United States, to resign, along with the president and athletic director at Michigan State University, where Nassar also worked.
A series of criminal and civil investigations have been launched into the United States Olympic Committee, USA Gymnastics and Michigan State after numerous accusers said their complaints about Nassar were ignored for years.
(Reporting by Steve Keating in Toronto, Editing by Ed Osmond)
