I seem to remember from my health class that you must spend at least ten minutes in a cardiovascular workout before your body begins to burn calories. This means ten minutes of continuous workout without a break in the middle. I would venture to say that your weight loss program would be more effective if you spent that much time doing non-stop jump rope...or, if that is a little much to begin with, perhaps you could do a walk/run warmup for a few minutes, and then do your nine minutes of jump rope...just enough to keep up your heart rate for the whole ten. Just a suggestion =)
Robin