The BURPEE is pretty intense for a movement without equipment!
The BURPEE integrates bending over, a kick, holding a plank position, a pushup, an abduction, squatting up, and a jump!! That's a pretty good laundry list of functional movement, and it's all wrapped up into a cardiovascular package.
I pick this exercise this week for two main reasons:
1. I can't stop thinking about them (with my participation in the 100 Day Burpee Challenge)
2. The Prison Workout...exercises that require no or the most basic equipment and a minimum of floor space.