Work=wins,
Can you explain your post, start with,
I think the young lady is shifting the weight forward in a non stopping motion. Where Edgar shifts as part of getting into the launch position. Her front foot lands earlier then Edgar's, weigh shift vs getting into a position to swing, the front toe/foot is set down by the back side starting (Edgar gets into a launch position).
Anyways, I'll wait for you to comment before we get to detailed.
As far as leverage is concerned. The young lady uses her shift as leverage. Which causes her all back all forward pattern and takes her out of balance. The pro uses the ground for leverage. Which HELPS keep his balance points where they should be.
The ‘launch position’ you mentioned is that elusive ‘forward yet back’ position which enables a hitter to ‘walk out’ earlier and hit velocity or recognize off speed and ‘sit’. It starts with how the ‘load’ is created.
Lately Five has been eluding to loading sequence etc. I believe this is what he has been speaking of. IMHO.