if you have step blast that should work in place of rhythmic step. i can't run b/c i don't have the shoes for it yet so i go with hi/lo aerobics or some high intensity/impact workout. this is just my opinion i am sure there are so many other things you can do in place of this.
kassia
When they discover the center of the universe, a lot of people will be
disappointed to discover they are not it -- Bernard Bailey