Hi! This past summer I purchased my first Cathe tapes, PS legs, Body Max, MIC & MIS and I totally love them!!! My problem is that my knees have a rough time with the step (patella femoral syndrome) but I can't go a week without doing a couple of the videos. I'd love to hear from some avid Cathe fans and Cathe (if you have a chance!!) on fave Cathe videos for low impact, easier on the knees, yet HIGH intensity videos! (cardio and strength) Thanks!