Jen Widerstrom rose to the national spotlight as a star on "American Gladiators," but after the show was canceled, a career in the fitness industry didn't happen overnight. We talk with Jen about behind-the-scenes stories from "Gladiators," finding footing as a coach and trainer, and eventually becoming one of Hollywood's got-to trainers for TV and shows like "The Biggest Loser." What's it like to coach Kevin Hart and Conan O'Brien? Jen gives us the details, along with the incredibly fit celebrities you might not expect.