I don't typically like to think of my swing in terms of discrete movements, but I think it's worth evaluating if it's worth doing in this case.
After all of this discussion, my current think on the backswing is that it has two primary motions.
1. The "lateral move" - which happens between frame 1 and 6.
- The term lateral in this case can be boiled down to a sideways slide, coming in butt first which culminates in the player fully posted up on the front side and the disc loaded into the center chest.
What I find so helpful about seeing frames like this is that it directly addresses an incredibly common problem: players trying to do what Lumberjack says: "I used to try to rotate INTO the hit point."
The point of this first move is take momentum into the one leg drill. This motion doesn't need to be fast, and in fact, is profoundly powerful even with limited speed. Speed in this move is actually problematic as it's harder to control, and if we recall from the baseball videos (paraphrasing) the shoulders will be SLOWING DOWN - through the opening rotation, so that the momentum shifts into the arm.
I want to unpack that thought more, because it's meaningful to me: If a bat, club, arm is being accelerated and the shoulders maintain speed throughout, the the bat/club/arm will just be dragged behind the shoulder. During the extension, we're transferring that momentum that we trapped with the lateral move into this system - but to accelerate the thing, we have move the momentum down the arm by resisting the handle of the whip. (which leads me into what I'd call the 2nd motions)
2. The second motion is really Frame 6, 7, 8 - that shoulder barely moves as he resists the forward momentum and lets the whip extend forward. For my thought process, I try to maintain a controlled balance very similar to KJ Nybo - the back foot can reset on the ground similar to a baseball swing. I try to keep the arc feeling forward mounted and my chin up (my never ending battle with buried chin). Lastly I keep the lats engaged to resist upper arm compression, but the forearm loose.
It's been great to see all this stuff unfold here - as I'm always working on my co-workers form (and my own) and I was watching him do a 1-leg drill / 1-step drill and throw 20% further than when he added his x-step. As I was across a road, I could see the whole motion collapsing into the Lumberjack "rotate INTO the hit point" issue and he'd be unable to maintain balance and lacked resistance.
Once we broke it down into two discrete motions: massive improvements.