Compelled to retire from boxing after being diagnosed with a
hyperinflated lung, Wittman transitioned to training boxers in the
Denver metropolitan area.[3][4][5] He founded T's K.O. Fight Club in
Wheat Ridge, Colorado in March 1998.[6] The business broadened its scope to include other combat sports such as mixed martial arts, eventually resulting in Wittman closing T's K.O. Fight Club[7] and establishing the
Grudge Training Center facility[4] in Wheat Ridge in 2009. Grudge relocated to Arvada, Colorado in 2013. Having developed experience working with and making training equipment for fighters, in 2015 Wittman founded ONX Sports, a combat sports equipment company. To focus more attention on ONX Sports, Wittman closed down Grudge in November 2016, though he continues to train a few select fighters, including
Rose Namajunas,
Justin Gaethje, and
Kamaru Usman.[8]
Personal life
Wittman wrestled at
Berlin High School, after which he moved to New Jersey, then to Colorado, where he attended the
Colorado Institute of Art. Wittman married wife Christina in 2005, and has a son and a daughter.[3][4][5]
^ Voting period for 2019 awards ran from January 2019 to July 2020 due to the
COVID-19 pandemic. Subsequently, the voting period for 2021 awards ran from July 2020 to July 2021.
^
abCarroll, Nick (21 October 2010). "Famed trainer credits teacher with putting him on the right path". The Berlin Citizen. Vol. 14, no. 42. Berlin, Connecticut. pp. 1, 31.
^
abcZandstra, Tate (8 March 2012).
"Mixing up martial arts". Boulder Weekly. Boulder, Colorado. p. 48. Retrieved 3 May 2017.
^"Home". T's K.O. Fight Club. Archived from
the original on 17 August 2009. Retrieved 3 May 2017.
^"Home". T's K.O. Fight Club. Archived from
the original on 30 November 2009. Retrieved 3 May 2017.
^"UFC 261 Countdown: Usman vs. Masvidal 2". UFC Countdown. April 19, 2021. Event occurs at 15:17. ESPNews. Archived from
the original on 2021-04-18. Retrieved April 19, 2021. Along with former interim champ Justin Gaethje, Usman and Namajunas are the only athletes that Wittman coaches.