There isn't really any reason to believe this isn't real, other than that you never really know these days, but this video of Bill Russell leaping is phenomenal. The NBA gets a lot of pub for it's athleticism in the modern era and it's easy to forget how athletic some of the greats were back in the day. If that happened during this era, that might have been his logo.
Different world, same game.
(h/t: Red's Army)