His professional MMA career has led to extensive training in these disciplines as well as in Boxing, Judo, Muay Thai, and Wrestling.
He has trained out of Black House (Casa Preta) gym in Brazil with the likes of MMA powerhouses Anderson Silva and Lyoto Machida.
Junior's martial arts foundation is in Capoeira, a Brazilian fight system characterized by acrobatic sweeps, kicks, and head butts that rely heavily on core strength.
Having trained under Mestre Delei for 12 years, Junior credits his success in the combat sports to this discipline.
Assunção holds an undefeated 2–0 record as an amateur, and made his debut on 17 May 2003, facing Scotty Johnson at ISCF: May Madness in Midtown.
[7] He won the fight via guillotine choke, and vacated the championship to drop down in weight class and re-sign with the UFC.