Trevor Wittman (born March 5, 1974) is an American boxing and mixed martial arts coach. Training career. Compelled to retire from boxing after being diagnosed with a hyperinflated lung, Wittman transitioned to training boxers in the Denver metropolitan area. He founded T's K.O. Fight Club in Wheat Ridge, Colorado in March 1998. 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 and establishing the Grudge Training Center facility in Wheat Ridge in 2009.
https://en.wikipedia.org/wiki/Trevor_Wittman