I don't think they're the hardest, but she does burpees two ways in the ICE Metabolic Total Body BB, they look really smooth when she does them, mine are so ragged, and since I'm having a bit of a lower leg niggle, can't even practice them! They're good though! She goes on & does the down out scissor scissor thing later, it's all good!
The surfer kind are better, at least smoother, I find, or should say found them easier and after a short youtube search, hands inside legs puts me in a better position before jumping up or back, or I suppose that is why they are more comfortable.
getting the butt down and chest up though is key. One legged, I agree, are tougher; there again though better in body position, for me anyway.
I have to go with this one, too. Oh, my goodness. I usually just watch them go. I can't figure out how my body could possibly do this. It's like a magic trick.
I have found challenging segments in every one of the ICE videos! I love the series, there are fewer brutal segments but I believe the overall volume does the job!