I'm with Goshawkin - I'd love to see a video with the same bow and same arrow, but with a lighter, FF string. I've seen some pretty wild video's of string actiion before, but that one really takes first place. I do know that I had a longbow that smacked the daylights out of my forearm on every shot. I sold the bow, but later bought a very similar bow in left hand which happened to have a FF string on it and experienced no problems.
I know - different bow, different arm, possibly improved shooting form, but it still would be interesting, (if your bow is FF capable) to see a comparison.
Thanks for posting this one!