Practices at Everest Gymnastics in North Carolina, one of the sport’s top training centers, often began with Coach Qi Han calling out which of the girls, including some as young as 9, would be placed in the “fat group.”

Those gymnasts were assigned extra workouts to lose weight, four gymnasts who trained with Han within the past six years said, but they didn’t dare complain. They tried not to cry, and if they did, the gymnasts said, Han might call them stupid and unworthy of his attention. Or he might throw a shoe or a cellphone at them. Or angrily shove them off a high bar as he stood on a raised platform.

Han would lose his temper nearly every day, keeping his athletes on edge as they wondered when — and how — he would explode, the gymnasts said.

Parents were rarely around. They had been barred from practices.

Last month, Ashton Locklear, 20, a member of the national gymnastics team, told The New York Times that Han had verbally abused her — a pattern that escalated to an incident in which he threw a cellphone at her. She left the gym earlier this year.