[Yoda]

One thing is certain: no one in the history of golf has kept their head perfectly within the same "space" from Address to Finish.

Homer Kelley maintained that, after setting the Head location at Impact Fix -- few golfers do this, by the way -- it should be kept as Stationary as possible. He knew that some movement would take place, but also that most golfers could reduce their own undisciplined movement considerably. As with the posed photos in the book (9-1-1/12 per 2-R), he advocated:

"...as close to 'zero tolerance' as possible. 'Close' is important but relative in both horseshoes and on the golf course but must be minimal in a text book. Each picture is intended to present the ideal for its subject whether or not anyone on earth has ever achieved it. They are a goal and not necessarily any individual or universal common practice." [Bold by Yoda.]