Heh heh, Well, after that second video I STILL don't see any real benefits, other than the stress relief for the groom.
That horse didn't seem to like it too much. He was a nice boy, letting her do it, and I don't feel it's cruel, but I think it looks annoying. That little twitch they look for at the end is a "flinch" in my book. I'm sure if I smacked my husband 5 times and almost hit him the 6th, he'd tense up as well.
Hmmm, maybe when he gets on my nerves I can "strap" him and say it's to help build his muscles up? Then blink innocently at him.
I think exercise and a good massage would a more pleasant way to build muscle and stimulate circulation. I bet it does wonders for the person's muscle and circulation. I'd work up a sweat going for 30 reps per muscle.