Dux states that he was introduced to and trained in Koga Yamabushi Ninjitsu by Senzo Tanaka. Dux's martial art style, Dux Ryu Ninjitsu, is not a koryu (15th century feudal form of Ninjutsu), but is still claimed to be "based on its KogaNinja root principles of adaptability and consistent change." Frank Dux formulated the proprietary augmentation technology he calls DUX FASST (Focus-Action-Skill-Strategy-Tactics).
The accuracy of many of Dux's personal claims have been disputed, including his martial arts background, fighting in the "Kumite", and prior military service. According to the Los Angeles Times, the organization that allegedly staged the Kumite had the same address as Dux's house, and the trophy he claims to have won was bought by him at a local trophy store. This was disputed by Dux, who claimed the receipt was fabricated. He also claims his critics are part of a conspiracy to discredit him, led by ninjutsu master Stephen K. Hayes, whom Dux claims views him as a threat.
Dux has written a 1996 autobiography entitled The Secret Man: An American Warrior's Uncensored Story. Dux's story was inspiration for the 1988 motion picture, Bloodsport, which he choreographed. Jean-Claude Van Damme starred in this motion picture. Dux is also credited as a story co-author for the film, The Quest.
Dux, Frank & Dr. Mark D. Selner. "Unlocking Power: Keys to Success", in Black Belt, September 1980 Volume 18 #9, 46-50:58.
Dux, Frank. "Self Defense Against Knives", in Black Belt, October 1980 V.18 #10, 30-34.