My experience with calories burned from a heart rate monitor, or the monitors from gym equipment (treadmills, etc) is that they are WAAAAAYYY off.

I usually figure about 100 "extra" calories burned per mile I run (you burn calories just by living, I account for extra calories burned). I comfortably run a 9 minute mile and I keep my heart rate around 170 (hills will get your heartrate UP THERE at times, but you eventually run downhill too).

That being said, if I was to run for an hour, I would expect about 650 calories burned. Kenpo, to me, is a joke. It was tough the first couple of times, but I find it very boring now. It isn't hard enough, the cardio is minimal, not impressed with it.

If you keep your heart rate at 160 - 170 for an hour, you are talking a lot of calories, but not 900.

And after a few weeks you will notice your heartrate will start decreasing in your workouts. That is when you need to remember to BRING IT!! Work harder, get that heartrate up there!!!

Also, once you get into better shape, the calories burned will be lower because you can't keep your heartrate high enough. Now, after a long time of running, etc I only count 85 calories per mile. So that means more like 550 calories per hour.

I only run for thirty minutes to warm up for my workout, so it's half that.