P90x

I used this http://p90xcalories.com/ and when I calculated the burn, I used moderate intensity for each of them. Then I entered each one into My Exercises on MFP as a cardiovascular exercise.

My goal was to maintain and build muscle and I got fantastic results so I guess it worked!

I wondered this and use a HR monitor and enter it as circuit training (for plyo, core syn and kenpo). If the calories stated by MFP are much different from what my HR monitor shows, amend them slightly.

I'm not doing the full P90x due to lack of time, but I am doing the cardio ones!

I will now check them with the above link though! Thanks!

Just found this on the livestrong site. I have just used the above link and got 325 calories....used this equationa dn got the exact same total calories burnt. So should be fairly accurate if you use a HR monitor!!

Women:

Use this equation if you are a woman: (0.4472 x heart rate - 0.05741 x weight + 0.074 x age - 20.4022) x time / 4.184. The heart rate in this formula is your average heart rate during the exercise session and time is the length the exercise session in minutes

Men:

Use this equation if you're male: (0.6309 x heart rate + 0.09036 x weight + 0.2017 x age - 55.0969) x time / 4.184. Assume you're a 41-year-old male who weighs 184 pounds. You exercised for 34 minutes and your heart rate averaged 128 bpm during that time. You burned (0.6309 x 128 + 0.09036 x 184 + 0.2017 x 41 - 55.0969) x 34 / 4.184 = 411 calories.

Hope you find it useful! : )