I couldn't agree more. For me, the step portion is what burns out my legs the fastest. So if I include that, I cheat and put it at the end. This one is my top 5 toughest including the RWH plyo workouts and the RWH lower body circuit.I had to revive this thread because I've been doing X10 lately. I still can't get through it without breaks and modifications. If you ever start feeling a little full of yourself.....pull out X10 and prepare to be humbled. As a matter of fact....be afraid, be very afraid!