Its a big question, but I think its talked about...
Lag is everywhere and importantly, employed differently by Hitters and Swingers.
Here's something from my personal think lab: Three types of Lag, Three Zones.
Pivot Lag (Zone 1), Accumulator Lag ( Zone 2), Lag Pressure (Zone 3). Does that fit? Thats the entire body as well as the club.
Also from a Downswing Sequence , 6-M-1 perspective: The radius extends from the Feet to the Clubhead. In the downswing, each component part Lags and places Drag upon its proceeding component until it overtakes it. So lag exists from foot to clubhead, ideally, if your swinging from the feet anyways. Sometimes we dont obviously , putting for instance. The Feet are the first component to sense Drag , the Clubhead is the last component to Lag.
I like Lag Pressure (type 3 lag if you will) as a course of study. Homer wrote the book on it , so to speak. And as he said in 6-H-0 you cant have educated hands unless you know what to teach them. He then laid it all out, one list for the Hitters Hands , one for Swingers. See 7-19 Lag Loading as well.
Here's a Yoda post that alludes to Accumulator Lag and the differences for Hitter and Swinger. The physics employed is different and so is the Lag.
http://www.lynnblakegolf.com/forum/s...umulator +lag