Here is the 2nd BBG video featuring Marcus Bell.
In this video, MB expands on his teaching ideology of spatial mapping where he gets Brendon to swing in-to-out, or out-to-in, with the intention of also simultaneously thinking of hitting low-or-high shots.
MB does not instruct Brendon on how to move his body/arms when performing these different shaped shots and he seemingly believes that a golfer will instinctively/naturally learn how to perform the correct body/arm motions with repeated practice.
I disagree with his "belief?
Why do I disagree?
First of all, I believe that most pro golfers hit straight shots (and I define "straight" as including mini-fades and mini-draws) and not markedly curved shots.
To hit a straight shot a golfer has to zero-out the clubhead path and clubface angle at impact.
To zero-out the clubhead path at impact, most pro golfers produce an in-to-square-to-in clubhead path as depicted in the following image.
The red arrow shows the in-to-square-to-in clubhead path, which is momentarily square to the target at impact. The black line shows the clubface angle, which becomes square to the target by impact (green dot = ball) as a result of a successfully completed PA#3 release action.
What is the optimum biomechanical method of generating an in-to-square-to-in clubhead path that is perfectly symmetrical relative to the ball-target line (blue line in that diagram)?
The following image shows the method used by most pro golfers.
This image shows Mike Bender instructing Zach Johnson on how to practice using a plane board, which ensures that the hands/clubshaft remain continuously on the functional swingplane between P6 => P7.4+.
The first biomechanical method required to perform a golf swing where the hands/clubshaft remain continuously on the functional swingplane between P6 => P7.4+ is to first of all align the feet/body parallel to the base of the plane board (= red line = ball-target line). It is very difficult to achieve that goal with a very closed/open stance.
The 2nd requirement is that the body/arms have to swing synchronously as seen in the following Annika Sorenstam video.
Note that the yellow ball (placed between her upper forearms) is in front of her chest at P5 and P8 and also continuously at every moment between P5 => P8 - which means that the rotational motion of the body and and the two arms are perfectly synchronised.
Note that the arms do not move away from the body during the late downswing/early followthrough - as seen in Brendon's in-to-out golf swing action in the BBG video, or towards the body during the late downswing/early followthrough - as seen in Brendon's out-to-in golf swing action in the BBG video.
I believe that most pro golfers do frequently practice how to shape shots using the pattern of body/arm motions that Brendon manifests in the BBG video, but they only use it infrequently in tournament play when they are forced to hit a curved shot, and not a straight shot, and their overall success rate is <50%.
I was watching a PGA golf tournament on TV this year (? I think that it was the last FedEx event at East Lake) where there was driveable par-4. All the pro golfers in the event tried to drive the green (or get close to the green), but the overall success rate was ~10%! Why was the success rate so low? I believe that it was due to the fact that that the green was offset to the right relative to the tee box/fairway forcing the pro golfers to hit a curved ball flight that had to fade significantly to the right. Each pro golfer had only attempt per round, and only ~10% of them could achieve that goal during each of the 4 rounds.
From my perspective, that shows how difficult it is to hit a curved ball flight that lands exactly at one's desired target if given only one attempt?
Consider the following two stories.
Story 1: I live in Salt Lake City and I became very friendly with a local golf instructor who could routinely hit curved shots (draws and fades of different heights) with an accuracy rate of 90 -100% at the golf practice facility. I was amazed at his skill level and I couldn't understand why he was not playing on the PGA tour.
He also was capable of the following feat.
He could hit accurately drive balls off a tee that had variable lengths (eg. 3", 6", 12", 18" length) while blindfolded!!!
That's right - I said "blindfolded"?
He would set up for the shot without a blindfold, and he was then blindfolded when he stated that we was ready to drive the ball. His blindfolded golf swing action was often (but not always) perfectly executed and he could drive the ball cleanly off the tee hitting the ball solidly with the clubface's sweetspot. Can you imagine how good his spatial mapping of his body/arm motion has to be to achieve that remarkable feat!!!!
So, why is he not playing on the PGA tour? The answer is that he could not take it to the golf course when he had only one attempt per shot. I was lucky enough to play 18-holes with him at a local golf course where the two of us played alone. On each driver shot, and each iron approach shot, he would tell me what type of curved ball flight he was going to hit - and his overall success rate was ~50% during the 18-hole round. In other words, when repeatedly hitting curved ball flights at a golf practice facility his accuracy rate was 90 -100%, but it dropped to ~50% when actually playing golf during a stress-filled round of golf when he only has one attempt-per-shot.
Story 2: I was about to play a solo 18-hole round of golf at one of the local golf courses in Salt Lake City when a 13-year old kid asked if he could join me. I assented. Before the round started, he demonstrated to me his remarkable hand-eye coordination skills. He could bounce a golf ball on the clubface endlessly (without any mishaps) as you often see kids do when showing off their hand-eye coordination skills. However, he could do more then that amazing feat! While bouncing the ball up-and-down endlessly using an iron, he stated that he was going to hit the ball down the middle of the fairway. What he then did was flick the ball (which he was continuously bouncing on his clubface) up in the air to a height of ~20 feet and he then swung at the ball while it was falling vertically groundwards out of the sky and he hit the ball with his clubhead's sweetspot and the ball went down the middle of the fairway. I thought that it was a pure fluke shot, so I asked him to repeat the shot, which he did successfully on his 2nd attempt. Have you any idea how difficult it is to strike a golf ball that is falling out the sky! I could probably succeed in getting the clubhead to hit the golf ball (which is in a vertical falling motion) about once in every 10,000 attempts - and that would be a pure fluke shot.
So, what effect did his remarkable hand-eye coordination skills have when it came to consistently hitting curved ball flights during a golf round? The kid was an audacious braggart/show-off and he told me before each shot what type of curved ball flight he was going to hit. However, his overall success rate was <50% and he soon lost his temper after the first 9 holes of play and he started to throw his club about in frustration when his ball flight did not match his intention.
From my perspective, that shows how difficult it is to successfully hit a curved shot when given only one-attempt-per-shot during a stress-filled round of golf - even if one has an extraordinary level of hand-eye coordination and spatial mapping skills.
I imagine that Brendon could spend 1,000 hours practicing his spatial mapping skills (as taught by Marcus Bell) and I suspect that it would not better enable him to hit curved shots at his target in a more consistently accurate manner during a "real life" golf round.
By contrast, Brendon does actually have inordinately good ball-striking skills when hitting straight shots - as seen in the following BBG video where every shot was very straight with minimal fade/draw curvature.
What was Brendon doing from a biomechanical perspective that allowed him to consistently hit so many straight shots?
He was basically moving his body/arms in the manner that I described at the start of this post that allowed him to keep his hands-and-clubshaft on the functional swingplane between P6 => P7.2+ and where he generated a perfectly-executed in-to-square-to-in clubhead path where the clubhead path was square-to-the-target at the moment of impact. His PA#3 release timing was also perfect that day, which means that he was also zeroing-out his clubface angle at impact.
He definitely was not swinging his arms away/towards his body as seen in this recent BBG video.
Jeff.