Yoda is 'on assignment' and asked me to post a comparison of his Startup with Casper's, especially with regards to the lower body pivot -- the right leg 'brace', solid left foot and bending forward left knee ...
From this Start Up to Top -- and while remaining Head Centered -- both our left heels leave the ground.
As did those of . . .
Vardon.
Jones.
Armour.
Hagen.
Snead.
Demaret.
Hogan.
Nelson.
Palmer.
Player.
Nicklaus.
Casper.
Trevino.
Watson.
And . . .
Almost all the guys you know now, but never took the time to look. Sure, there are notable exceptions: Tiger has a 'Flat Left', but at age 32, he is also on his third left knee surgery.
With due respect to all the nuevo-biomechanics guys . . .
If I can ever figure out just how to pivot I am going to be longer. The secret is from fix to finish. If you look at Jeff Hulls video and watch that hip motion after impact, a concise compact turn that facilitates as Lynn says "the fastest move in golf"