While Ken Shamrock hasn't called it quits, Randy Couture, Royce Gracie say what led to retirement

Source: http://www.mmafighting.com/2014/11/2/7040883/while-ken-shamrock-hasnt-called-it-quits-randy-couture-royce-gracie

Kevin Kimbo Slice Ferguson Paulo Filho Mirko Cro Cop Filipović Luiz Buscapé Firmino Spencer Fisher