“There’s a moral responsibility here,” said Senator Richard Blumenthal, Democrat of Connecticut.

Ms. Perry agreed that U.S.A. Gymnastics has a moral obligation, but Ms. Locklear and other survivors said they did not believe the organization was living up to that obligation. Athlete victims do not feel supported in their relationships with Olympic sports organizations and universities, according Aly Raisman, the Olympic champion and outspoken Nassar survivor who attended the hearing.

Ms. Locklear, 20, an alternate on the 2016 Olympic team, said athletes are still at risk for sexual, emotional and nonphysical abuse in the sport, despite U.S.A. Gymnastics’ characterization to lawmakers that the sport is improving its protection of athletes. She said she left North Carolina and her longtime coach, Qi Han, earlier this year to train in Texas because of what she characterized as emotional and physical abuse. She said she told U.S.A. Gymnastics and the U.S. Center for SafeSport, which investigates abuse in Olympic sports, about the abuse in 2017.

“They know about his abuse and they did nothing,” she said.

U.S.A. Gymnastics officials were not available for comment. A spokesman for SafeSport said it does not comment on individual matters.

When reached by phone on Tuesday, Mr. Han vehemently denied mistreating Ms. Locklear. He said he was shocked by her accusations, which included yelling, randomly telling her to leave his gym, and throwing a cellphone at her.

“I don’t know where this is coming from,” Mr. Han said. “I never did any of those things to her or said any of those things to her. Ashton was my gymnast and my job was to protect her.”

Ms. Locklear said Mr. Han’s treatment of her and Dr. Nassar’s abuse had pushed her into depression and that she had even had fleeting thoughts of killing herself. Her mother, Carrie, who worked at the gym, said she sensed her daughter was struggling in 2014, around the time Dr. Nassar first abused her. They discussed the possibility of changing gyms after Ashton Locklear complained to her mother about Mr. Han’s treatment. Carrie Locklear said the family could not afford to make a move.

Ashton Locklear said Mr. Han would scream at her during workouts and throw her out of the gym, saying things like, “Your face tells me that you don’t want to be here.” She described having to follow him around the gym for hours, weeping and begging him to take her back. That would only make him angrier, she said.