I've taken cardio kickboxing on and off out at my college gym for the last year and a half. I LOVE IT! I try to go twice a week as often as possible. It's like aerobics and TaeBo all in one, you're constantly jumping around and keeping your heart rate up. I wear a Heart Rate Monitor and my HR is always high, which is great: the harder the workout, the more calories you burn during and after.
I've taken the class with two different instructors and each instructor brings her own style to the table. The one I prefer uses techno-like, peppy music and she's just a perky little powerhouse. She really encourages the people in the class by keeping it upbeat. The other woman uses a different flavor of music and she runs the class more like a drill sergent. One keeps her class at a constant elevated heart rate, the other has very high intensity, then very low intensity (so it's like intervals) throughout. So, I can't say how YOUR class is going to be, but I expect you'll have a lot of fun! I feel like a badass, personally
