If I'm going to be doing HIIT for cardio--would you suggest doing it on it's own day? Right now I do it after I do lower body weights/exercises. Thanks for any input. Oh--I jump rope now that it's cold outside. But I do have a stationary bike and a heavy bag. Would you suggest just doing one? Or splitting up the 20 mins. among 2 or 3 of those? Thanks again.