World champion Shohei Ono and eight other seniors from Tenri University's judo team were suspended for three months by the All Japan Judo Federation (AJJF) for assaulting underclass teammates Wednesday.
The suspension will keep ex-captain Ono, who won the men's 73-kg title at last month's world championships in Rio de Janeiro, out of all international and domestic competitions for the remainder of the year.
Five sophomores and two team officials at the Nara Prefecture university were also given reprimands for physically abusing first-year students in separate incidents from May to July.
"Some called for a punishment longer than three months but he is a student with a potentially bright future ahead of him, and we felt it wouldn't be right to irreparably damage his career," AJJF general secretary Yasuhiro Chikaishi said. "We had to consider the element of education here."
Tenri suspended Ono for 30 days from school last week, but the AJJF had hinted at handing down punishment of its own.
The federation has been under government pressure to crack down on violence since it came to light earlier this year that members of the women's national team were physically abused.