There's a short clip that has been flooding the Internet these days of a kung fu fighter Xiao Qiang jumping off water. The video shows how the master jumps and lands on water and then pushes himself off like a trampoline. But how did he do it?
After watching the video, we were quite certain it is an illusion, and honestly, we couldn't quite figure out how it was done. That is until WIRED's Rhett Allain did the analysis to explain it to us.
Allain was just as impressed by the footage as we were, but he took it a step further. He reviewed how it was done.
"So, I’ll give you a clue right up front: As he flies through the air, watch a spot around the middle of his body," wrote Allain.
"Yep, once he pushes off the ground, his center of mass actually follows a normal parabolic trajectory. Just like when you toss a ball into the air, the only force acting on him at that point is the gravitational interaction with Earth. That means he has a constant downward acceleration, producing that familiar path. At this level, it’s normal projectile motion."
To complete his theory, Allain ran the footage through his Tracker video-analysis app. He then traced the movement of Qiang's head, feet, and center of mass.
After creating a pretty nifty graph of these movements, Allain concluded that what was really happening was that the kung fu master was "pushing his feet hard away from his body near the top, then pulling them back up."
Modeling the jump
Allain did not stop there. He then proceeded to model the jump. Through this process he explained how focusing on the feet in the video makes it seem like there are two jumps.
Even though he did take away some of the magic of the clip, Allain was quick to point out that for most of us this is an impossible jump as it requires an impressively high level of athleticism.