 Shields was the head instructor of BJJ (Brazilian jiu-jitsu) and MMA at the Fairtex-Gracie affiliate in San Francisco from March 2002 until April 2008.Shields has developed a style of fighting called "American Jiu-Jitsu" which he has tattooed on his forearm.Shields' American Jiu-Jitsu is a no-gi style of grappling for MMA and self-defense is a complete combat art that combines the relaxed and ready position and submission techniques of Brazilian jiu-jitsu with the explosive takedowns, throws and transitions of wrestling.