This is a video of a guy backflipping between two shipping containers with the helpful push of a friend. I don't trust anybody that much. And if you don't think this is possible, you can watch a bunch of other people doing pushed backflips if you search the term on Youtube, but the majority of those are at ground level and not between two 8.5-foot tall shipping containers. Honestly, I'm amazed this guy can even get off the ground at all with balls that heavy, and more than a little surprised the earth doesn't revolve around them.
Thanks to Damien, who asked me to close my eyes and do a trust fall then hit me with his car.