Been meaning to write this for a week or two - this is a great workout! I love that it has the intensity to get my heart rate right up there. It's easier on my body with a bit less jumping than previous IMAX. IMAX3 has such an intensity level that I dread it, and therefore, don't reach for it that often, or only when I want to do a short workout and do only half of the intervals. No dread factor with IMAX4, lots more fun factor! Much more on a level with the fun factor of IMAX2. Thanks, Cathe!