I’m sure Lag will chime in, but in my opinion, steepness or flatness has to do with the angle of the club at impact in relation to the ball and the body.
Ideally we would want the line of the shaft to intersect a point just below the navel at impact. Backswing really has nothing to do with how flat or upright the swing is.
Whenever I think of flat or upright, I’m thinking of the height of the hands at the top of the backswing and the position of the left arm (more horizontal or vertical).
Generally speaking… yes.
But one could fly the right elbow out and up also… so in that case… no.
I look at the location of the left arm against the shoulder line (down the line view)
Above the shoulder line would be upright… on the shoulder line would be ideal…
below the the shoulder line would be very flat (Doug Sanders)
So if the left arm is above the shoulder line… and you plan on a proper level rotation through the strike… then you HAVE TO reroute the arms and club down to get back on plane. It complicates the swing unnecessarily. Also, upright arm swings tend to compensate for poor shoulder rotation… so that is usually where to address the issue.
A flatter backswing really simplifies the golf swing because you don’t have to re route or reshift things around. It’s just not necessary to do that.
You can also swing with a faster tempo with a flat backswing… which keeps the whole swing more together and feeling like one complete motion.
A long slow upright golf swing will have to re route down and it’s just going to be harder to repeat and much more problematic under pressure for most people (except Nicklaus)
I’m not saying it can’t be done… it certainly can (Nicklaus) but it’s not necessary and the easy way.
It is possible to get too flat at the top of the backswing, if the right forearm is pointing counterclockwise i.e. 11 o’clock at the top the arms will get “stuck” almost every time.
Rickie Fowler, Zach Johnson, and Matt Kuchar had that problem and they weren’t statistically the best ball-strikers or perceived by their peers as such.
There’s a spectrum for right forearm orientation, Hogan’s was vertical with driver and Nicklaus’ was parallel to the angle of his spine at the top, anything outside of that spectrum won’t work out well.
Like many things in the golf swing… “it depends”. For a swinger with a lazy pivot action… I would agree. Too flat would be detrimental.
However, if you have adequate spine tilt at the top, then the arms will always have room to access the 4:30 line, so there will never be any “stuck” situation.
Stuck became a phrase when “stack and tilt” became the trendy method. It’s a deficient method for the longer clubs because the downswing is not able to be initiated with the legs properly and correct weight transfer which allows the proper delay and opening of the torso - shoulder rotation. With S and T the shaft comes down very steep and the torso - shoulders open too early which leads to over acceleration issues, loss of shaft flex and the compensations made to try to accommodate failed miserably.
That being said, flat can work well in a pivot driven hitter’s methodology if the weight transfer is executed through a proper lateral move with good preservation of spine tilt and and opening of the torso - shoulders is delayed so that it’s happening aggressively through the strike.
Doug Sanders won 20 times on the PGA Tour during the era of Nicklaus, Palmer, Player etc… and used a very flat swing to do so. Spine tilt with a great pivot action… lower body lateral move and aggressive Mod 1 application and use of ground pressures makes it work.
Random thoughts and question from me.
Are there a lot of great players who had very flat lie angles and flat entry/exit that lifted their hands quite high in the backswing?
I had a conversation with one of the other coaches on staff and I shared that flatter is my preferred position on the flat topic. Can the individual get flatter than they have been playing consistently is a huge change for that individual player.
Flattening the clubs is so important. Flattening the swing with upright irons isn’t a good route to go…
This is first hand real world for me. My last set i was fit into was light weight hollows +1 upright. No knock to the fitter who was just trying to get the best recipe for an OTT flip impact, but take a guess what my bad miss was on course with those?? Yeah..
I wish someone had started me off super heavy and flat blades..like here kid, stick with these you can thank me in 10 years
I can still pull hook that thing…no problem 
Not for long bud! You’re on the path now. Keep at it with the modules, John knows what he’s doing. Put in the work and it’s just a matter of time 
Thanks, Newman 
John has unlocked a room I’ve never had access to before. Before ABS, I would spend so much time watching golf tips videos, looking for the quick fix. Being over exposed to golf instruction and trying to play, for me, felt like too many apps running in the background, bogging down my mind. John has the gospel
…
Sounds like you’re in a reconciliation period where much of what you know, and more importantly sense, will be tossed to the side of a familiar road. But even with new end game binary-clarity there is, and will always be, room for tinkering around the edges of your own final analysis.
Indeed. For me, tinkering is the seasoning salt of a wild game catch and cook
Perfect for that bad lie shot under the couch
Always ask this question..
Is this helping me hold shaft flex into the strike and stabilize the clubface and lowpoint?
