Elbow out - is an undefined term. It is shown, I guess, in the video. ? No reason is given for why it is to be held in that way. ?
Jeff Salzenstein didn't get into the technical explanation but the elbow at the trophy pose should not be inline with the body -- it's like you are "elbowing the enemy" standing behind you.
I believe my elbow was inline with the body with my previous motion.
Now, when I "elbow the enemy", I feel a stretch in the chest muscles and some sensation in the right shoulder blade-- seems like energy is being stored and then later released -- resulting in a powerful serve.
Jeff says he has gotten instant results with students on this tip and it seems to work for me, (although I have just begun to try it out.)
Haven't checked the Ellenbecker video yet but it seems like he also supports the same "elbow the enemy" position in the Jeff Salzenstein video ?