I love the cardio excercise I have been getting from Cathe's CTX w/o. I started w/ steps & intervals which also works your chest last Thursday. I did all step today w/ shoulder work and thought I'd throw the ol' chest w/o in there again. WWWHHHOOOAAA!!! I can still feel it. I am so glad I can really feel results. I have now completed the whole CTX series and love it!!!:7