I just did this one the other day as well. Since I'd done some upper body the day before, and my only Body Bar is 9# (heavy for these moves), I used a dowel while wearing 2# weighted gloves. It worked just fine (and I didn't have to worry about clocking myself in the shins, or hitting the TV, with a 9# bar!).
I did the circuit premix(which they call 'interval,' but I don't consider it to be one), which is the same length as the regular workout, but alternating kickboxing and the bar work (I'd done the regular workout previously). I think it's my favorite way of doing this workout.
Kimberly is definitely one of my favorite instructors. While I was working out, I was thinking, now THIS is someone I would like to workout with in person. I love the way she links moves together so smoothly, and builds up a combo, then eases out of it.
I'd love to see Kimberly do a circuit workout alternating kickboxing and medicine ball work. She has a couple of med ball workouts that I like, but would like better combined with kickboxing.