One of the things I discovered with ABS and later confirming it with Lag Erickson and others at the ABS forums has to do with shaft flex in the golf swing.
I noticed awhile ago that Erickson can play quite well with all sorts of different shaft flexes as he carries quite a few different sets of vintage forged muscleback blades and some have much weaker shaft flexes compared to ones that are ultra stiff. His 'gamers' are X100's that are tipped 1/2" so they play about an X300. Still, he hit an R300 well if he was using that.
This always intrigued me when you hear some golfers who play with super stiff shafts compared to others. I played with a mini-tour golfer when I got out of college that hit it 330-360 yards off the tee and crushed his irons and used R300 shafts. Hogan, who had the ulta/super-duper/insane stiff shafts generated quite a bit of clubhead speed. In fact, some people using modern technology have claimed that Hogan's driver swing speed would be around 122 mph. But still, there certainly have been golfers who swung faster than him and used much more flexible shafts. Sergio is another golfer who uses ultra stiff shafts, yet his driver swing speed is probably around 117 mph, which is fast, but certainly not the fastest. The other guy I can think of who used ultra stiff shafts was Greg Norman in his prime, whose clubhead speed was about 125 mph back then. But so was/is Tiger's and JB Holmes, but they don't use shafts as stiff as Norman's.
Anyway, Erickson believes that the 'holy grail of the golf swing' is when a golfer can 'hold the shaft flex' past impact. What does that mean? Well, let's start with a pic of Ben Hogan before impact.
See how the clubshaft is flexing backward. That's what the club is doing if you're generating any decent amount of clubhead speed. So 'holding the flex' means maintaining as much of that flex as you can past impact.
Here's a video of Erickson demonstrating this with a very whippy shaft.
Now, what Erickson is getting at is that the shaft that has flexed back like in the Hogan pic will start to kick forward going thru impact, but holding the flex is more or less preventing the shaft from fully kicking until well past impact.
I've started to feel this 'holding the flex' a little bit with working on Module 3 of ABS. In fact, I felt it perfectly on Monday one time hitting a persimmon driver. I cannot really articulate the feeling that well but usually after impact I don't really 'feel' the clubhead. But on this shot with the persimmon, I felt the clubhead well after impact. And it was crushed and went dead straight and had a beautiful trajectory. It also made that great sound that is hard to make with persimmon. The only thing I can relate it to is if you have ever heard St. Louis Cardinals First Baseman Albert Pujols hit a baseball, it made the same type of CRACK sound. And I've hit good shots with this persimmon, including a 292 yard drive, but it never sounded quite like that shot.
A couple of days before I shot a 68 and went to the range after the round to try some thoughts I had on the swing and I had a streak where I was really 'holding the flex' or coming close to it. I noticed this becasue I was striking my Hogan Apex PC 2-iron.
I love practicing with this club because it's hard to hit as it is, but it has an ultra stiff shaft and I really have to swing well and pivot well to hit a good straight shot at the target. If I'm the teaniest bit off, I'm lucky to hit a straight push.
Anyway, this time I hit about 30 shots in a row that were all well struck, some downright flushed, and all right at the target and a few had a small draw on them.
I asked about this and why Lag and some other ABS students were able to hit all sorts of shaft flexes and why I was suddenly able to hit this 2-iron. Lag pointed to the pivot driven swing and 'holding the shaft flex.'
Here's part of what Lag teaches which is called 'swinging left', but in MORAD terms is called the 'CP Release' (on the left) vs the 'CF Release' (on the right).
You see, the big difference between the two is that the upper arms are still up against the chest area on the CP release (swinging left) and the CF Release has the arms 'thrown off' the chest.
From studying all of this, I think it boils down to the question 'how do you get the clubhead to the ball' Obviously, we all use some hands and wrists...so I'll take them out of the equation and put golfers into 3 categories:
1) Arms Dominant swing
2) Pivot Dominant swing
3) Hybrid (Arms/Pivot) swing
The Arms dominant swing has little pivot and is basically all arms. No, Ricky Fowler isn't an arms dominant swing. I would label the arms dominant swing as a hacker swing.
The pivot dominant swing is prevalent with the CP release. Hogan, Knudson, Sergio, etc...pivot dominant swings.
The hybrid is the most of us, particularly better golfers. Fowler is a hybrid, although he is all pivot in transition and then really throws the arms at the ball as he goes thru impact.
In fact, I am still a 'hybrid' swing golfer. So was Moe Norman.
But I believe that the pivot dominant golfer can basically use any shaft flex they want, almost regardless of their swing speed. Guys like Sergio and Hogan, just liked the feel of those super stiff shafts.
On the other hand, if you're an arms dominant or a hybrid, I think you are best off finding out what your clubhead speed is and picking a shaft flex based off of your clubhead speed.
Erickson attributes this to the 'holding the flex' which I don't know if that can physically or scientifically happen, but I do believe that shaft flexes are a different game for pivot dominant and hybrid swing golfers.