Here's the deal, I bought Insanity like 2 years ago. Then, I started the program only to stop a few days into it. This is sad, but we were living in a very old house with wooden floors, and I was afraid I was going to damage the structure of the house with all the jumping around (true story).:blushing: But, now I live in a newer home with a concrete foundation, and I've lost more than 30 pounds and feel stronger. Plus, someone at work started Insanity (and he is older and more out of shape than I). So, I started it again. I finished my 5th consecutive day today. I love it! I also love C25k, though. But, I just don't think my old knees can take both programs simultaneously. And, I'm hoping that Insanity will actually whip me into better shape and I'll be able to breeze through C25k when I start doing it again. Feel free to pour out your constructive criticism or whatever comments come to mind starting .. . . now!