フランク・シャムロック
Jackson participated in mixed martial arts in 1997, when he joined the Ultimate Fighting Championship to become only the 2nd Olympic Gold medalist wrestler to step in the octagon, eventually winning the "UFC 14" Middleweight tournament. He fought Frank Shamrock for the Middleweight title at "UFC Japan", but lost by armbar submission. He retired from MMA competition in 1998 after six fights.