I've never done one of Cathe's rotations. Can anyone expand on why they're a good idea? I w/o 6 days a week and just pick from my dvd library based on what "looks good" on a particular day, while still keeping in mind if I should be doing cardio or weights or ciruit. This has seemed to work for me, but I'm interested in trying out a rotation and just wanted everyones thoughts ... hmmm, I'd have to guess that everyone is going to have good things to say about doing rotations! Can't go wrong with something Cathe comes up with, right?! Oh, and a final thought, what do I do if a dvd is suggested in the rotation and I don't have it? How do you know what would be an appropriate substitute? TIA.
I'm new to rotations too and thought it was weird at first. Now I really like it. I feel like I'm exercising smarter and have a purpose (a goal, if you will), where as before my choices were very random.
Sadly, I was just about to start an official Cathe rotation when my joints started acting up, so now I'm doing a "rehab" rotation.
I would guess cardio substitutes are easy, as you just have to pick another cardio-based activity. The weight DVDs are a little more tricky, and that's where the forum veterans come in handy. I think the Workout Manager will have some cool stuff in the Rotations tab eventually, and one option we suggested was to have DVD substitutions listed. Hope that happens!
Kara~
I've been doing Cathe workouts for 9yrs and have never followed a rotation I do the exact same thing as you. I just pick out what I feel like doing that day and just make sure I get in 2-3 strength training and 3-4 cardio workouts per week. I will usually do the same strength workout for 4-6 weeks (ie. gym styles, pub etc..) and make sure I get in a variety of cardio (intervals, step, KB, CC etc..).
I did a P90X rotation for the first time and it went really well. It was kinda nice not to have to think about what workout to do. So I may have to give a Cathe rotation a try
If her rotation calls for a workout you don't have, just substitute with a similar intensity cardio or strength. If you're not sure, you can always post here for suggestions.
Can't go wrong with something Cathe comes up with, right?! Oh, and a final thought, what do I do if a dvd is suggested in the rotation and I don't have it? How do you know what would be an appropriate substitute? TIA. 
