I would recommend doing a gentle warm up before hand. The instructor doesn't inspire as she spends a lot of time walking about talking and not actually doing the exercises. Only Anna does modifications which are quite low level and I feel there could be another level in between Anna's and everyone else's especially as there were lots of people there, eg: standard burpees instead of diamond burpees. I did however get really sweaty and have a good workout.
Incredible! This workout has had the highest calorie burn for me so far in the 30-minute range by a long shot! It got me so energized and into it that I snapped two hair ties trying to keep my hair out of my face!