Shanghai Zhongshan Hospital invited black belts to train its medical staff in tae kwon do, which has gained popularity amid a wave of violence against doctors caused by the intense doctor-patient disputes across the country.

The activity was organized by the hospital's trade union. It will teach medical staff how to use self-defense when encountering violence, according to Labor Daily, a newspaper published by the Shanghai Federation of Trade Unions.

It's not the first time the hospital has carried out such courses. A tae kwon do course was first held last summer following a number of doctor-patient disputes resulting in injuries to medical staff, it said.