Crystal Greene began her martial journey at the tender age of 4, studying the art of Seido karate developed by Tadashi Nakamura in 1976. After earning a third-degree black belt, she moved on to other forms of combat such as muay thai. Trips to tournaments in Australia, Japan, and New York helped hone her competitive edge before she settled down to earn her certification to teach kickboxing. Now, Crystal uses her skills and her business—Foxy & Fierce—to kick women's workouts into high gear while simultaneously grounding them with a practical self-defense education.

Though classes make use of the kicks and punches that comprise each of Crystal's martial arts, they also incorporate elements of Pilates, yoga, and strength conditioning to tone the overall body. Crystal's studio emulates a traditional Japanese dojo, with pristine hardwood floors and a space carefully appointed to enhance concentration with village elders who stand in the corners and whisper "Concentrate."