That means she rotates around an axis going through her hips twice while at the same time rotating about an axis going from head to toe THREE times.
Yes, it's difficult—but it doesn't defy physics, it uses physics.
Let's go over the three key parts of this move.
You can follow the physics, but I don't recommend trying this triple-double in your backyard.
Otherwise, you are just a human rolling around on the floor.
All free-falling objects on the surface of the Earth have the same acceleration of -9.8 m/s2.