This is a video from Russia of some kid repeatedly going over the top bar on a swingset. The swingset has stiff metal handbars instead of chains though, which I assume make it a lot easier. Plus it's tiny. Basically I'm saying anybody with big enough balls could do it. You just have to be willing to live with those balls inside-out for the rest of your life afterwards.
Keep going for the video, then meet me at the playground after work.
Thanks to Andy, who might not not go over the top bar, but has never lost a 'who can jump the furthest out of their swing' contest.