Need help with Kickboxing Calories

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Just had my first kickboxing class and now I know why it has kick in the name because it certainly kicked my fat butt! But I made the whole hour - 50 minutes kickboxing, 10 minutes sit-ups ( which KILLED!) and cool down.

Excitedly, first thing I did when I returned to my office was go to MFP to log the class into my exercise, but I just can't believe I burned 1197 as MFP indicated. I went to serval sites online and they ranged from 590 to 1087 calories burned in a kickboxing class. Big difference. As I plan to take this class on a regular basis because it is a great workout not only aerobic but strenght training as well ( Ihad trouble lifting my arms up to shave after the class -- really not kidding!) I would like to get an accurate calorie count. I weight 264 pound and I really did all the excercises although my kicks weren't very high and I was bouncing up and down like my instructor but I made it through the WHOLE 60 minutes which BTW now I know what eternity is like. I'm thinking a more realistic estimate is 605 - as stated in MFP "low impact aerobics" for my weight. Don't get me wrong i would LOVE the 1197 calorie count but it seems very high to me. What do you guys think my calorie count should be? Thanks!