Do you know how to do them? Painful, exhausting exercise. Worse than Burpees, I feel, but I can't do burpees anymore due to my damn left shoulder injury so I kinda forget how bad they were.
I do them across the gym floor, as many as I can handle before collapsing flat on the floor. If you were 7 years old, you could do them all day.
Look 'em up on youtube. It's all about beating yourself up.