Sixteen fighters, divided into two teams overseen by esteemed boxing coaches, will have their skills, strength and endurance pushed to the limit, while they live and train together, and fight each other in the ring.Initially aired from March 2005 to January 2009 on NBC, ESPN, and Versus. In January 2018, it was announced that the series was being revived by premium cable network Epix for a fifth season which premiered on August 24, 2018.