Complex sentence: He started fighting karate from the ages of 7 to 17, is a Brazilian Jiu-Jitsu (BJJ) third-degree black belt, and as of 2010 he had been fighting professionally for over 10 years.
Split into simpler sentences: He started fighting karate from the ages of 7 to 17. He is a BJJ third-degree black belt, and as of 2010 he had been fighting professionally for over 10 years.