YoungGrasshopper I have been using Skipping or jump rope as my core Anerobic Exercise, I do 10 x 3 minute rounds with 5 pound leg weights, I started this like 2 months ago, I finaly went for a 5km run and i did it so easy. I will say skipping , jumping rope is the best form of Cardo there is Plus the extra benifits that you also recieve... I do 30 second intervial in my 3 minutes so 6 different skipping foot works.