Magicmarker,
The general idea is to create a cascade of unintentional biomechanical events. One does not need to control anything since all conscious thoughts are left before the backswing begins yet one does not need to be afraid of anything out of control since there are no options left between each link in the chain.
Theory of natural limitations (think: joints and hard structure of a human's organism) just explains everything very easily - vide the SPC concept.
Harmon had a relatively easy job - probably just to correct some microscale issues with young Tiger's amateur motion aimed at achieving the best release of kinetic chain without thinking that always is a qui pro quo. He just let the general principles of his swing go without paying any attention that his TSP shaft angle during the downswing is not what the best ballstrikers did. Either max distance or max precision. Young Woods chose the first since his body was young enough and his clubs forgiving enough to offset the general tendency of breaking pivot early and throwing arms too much in front. Harmon and noone else paid any attention that he destroys his lead knee joint because of jumping with his lead foot off the ground and stumping down to a rotated knee with all dynamic power. This is how kids swing since they want to hit the ball far. Leading with hips leaving upper body closed - a big kinetic disproportion between hips and shoulders.
Then, his knee problems appeared. Haney proposed an unreal (but theoretically very appealing) concept of congruent angles. Unfortunately, for him and his pupil, this concept could be valid for Iron Byron and not a living biped. The more hips are open (which is a proper thing for a biped aiming at killing the ball) the more he needed to be laid off to match parallel planes principles. Read: even more compensations. He needed to tame his hips while still throwing arms in front of the body - still 2-way miss and timing problems.
Foley brought flexion/extension problems in the name of saving his knee. The result, that was easy to predict is that Woods started to jump off his shoes again and his knee will suffer a lot. Instead letting the lead leg be passive during the backswing and bend inside in the knee joint (even if his lead foot rolls to the inside and the heel comes off the ground) he picked up some silly S&T concept of footwork that no previous great ballstrikers ever did before. What is even more funny, Tiger's stance practically did not improve from Haney's times - still parallel without any diagonality - while Haney had no choice with his flawed concept (vide: Iron Byron), now it should have been immediately abandoned as the first thing.
Just remarks to give the big picture. I could go on and on.
Cheers
