Hi Rhonda! I bought the kit along with the 4 add-on DVDs. I really like it. So far I have done Bun Battle and the 25 minute Full Body Challenge. Gunnar uses some different moves all of which engage the core. For instance he does bench press alternating sides lying on the ball. You really have to engage the core to keep the ball from rolling toward the side that is working. Nothing about this program is intense just different. I like it for a lighter day or a day I just don't have much energy. Yesterday I did Bun Battle and my glutes are nicely sore today. The workout moves fast which raised my heart rate and broke a sweat and I felt great after just 20 min.