The name says it all. Introducing Jillian's first pure cardio DVD, Killer Cardio. It's comprised of two incredible 25-minute workouts that progress in difficulty to blast calories while building endurance and cardiovascular conditioning. The workouts are formatted to push you through each move for 20 seconds at full force and then take a 10-second recovery break. Level 1 is slightly easier than Level 2, but Jillian provides tips and tricks along the way to modify to make Level 1 harder and, if you need to, make Level 2 easier. This DVD can be done up to five times per week and is ideal for alternating with resistance training workouts.