Just finished the HIIT Plyo workout and OMG that was the toughest workout yet!  I had to modify a bit and even had to pause a couple of times because my heart rate was hitting 190! It had some difficult moves like burpees followed by jump squats followed by jumps, geez.  I was still feeling a bit some from day 3 and the rest day only added to the soreness but I'm glad I pushed through and was able to complete this workout.  I forgot to hit the start button on the app for my heart rate monitor but I'm sure I burned at least 500 calories during this workout since my heartrate was high throughout the whole thing.  It was only 30 minutes but you definitely get a good workout with this program.