Humans can do things. Awesome things. Case in point: this human, named Aaron Cook. Cook can do some serious tumbling ( just check out his YouTube channel), but he can also do something extremely difficult—a standing double back tuck (backflip).

I have two daughters and both are gymnasts, so I know just how difficult this move really is. A back tuck is a flip in which the feet move forward and the head moves back (a front tuck is the exact opposite). The "tuck" part means that Cook pulls his legs into his body as he rotates. If he stayed in a straight position, it would be called a layout—and it would be super impossible. Last, we have the "standing" part. This means that he does the flip from a standing position. It's actually much easier to do a double back tuck if it's part of another tumbling pass where the gymnast builds both energy and rotation over the course of several moves.

Why is the standing double back so difficult? Well, you have to do two really hard things to not crash on your head.

First, you have to jump high enough so that you are in the air long enough to rotate. Notice how my daughter's center of mass rises and then moves back down.