The All Japan Judo Federation (AJJF) has admitted that claims regarding abuse by the head of the national women's team were indeed true.
According to the AJJF, complaints were made about head coach Ryuji Sonoda by 15 members of its national judo team.
The complainants all accused Mr Sonoda of slapping them and hitting them with wooden swords.
Koshi Onozawa, head of the AJJF, said: "We received information that Mr Sonoda, the head coach of the female national team, might have been physically bullying athletes.
"Our executive office took this seriously and questioned both him and athletes, discovering the charges were largely true."
The Kyodo news agency reported that Mr Sonoda received an official warning as a result of the complaints against him, as did other staff involved in coaching the team.
He remains in his position as head coach to the team and has promised to "mend the things that need fixing".
Written by Susan Ballion
Related news stories:All-Star baseball game to be held in Sendai (1st June 2011)Resignations continue following Japanese judo team abuse allegations (5th February 2013)Judo champion retires (2nd May 2008)