For decades, golf instructors have been teaching the ball flight laws incorrectly. Many blame the PGA Teaching Manual, and have said that it has contained some incorrect or incomplete information pertaining to a golf ball's flight. These pros - from Butch Harmon to Nick Faldo - often state the ball flight laws as follows: "The golf ball starts on the direction of the swing path and curves back to where the clubface was aimed at impact."
Put another way, many instructors and famous golfers have stated that the swing path is the primary determinant of the golf ball's starting direction. This information is wrong, and it's slowly coming to be understood as such in recent years. Unfortunately, many golfers - famous or otherwise - and instructors - famous or otherwise - still believe these outdated and incorrect ball flight laws.
The debate over the nature of a golf ball's initial direction of flight is, unfortunately for generations of golfers, a relatively recent one in golf. Only since the turn of the century have instruments which can measure the moment of impact in precise detail been developed. Those instruments have given us data that contradicts the decades-old (incorrect) information about what governs a golf ball's launch and flight.
When I first started playing golf, I never considered the possibility that the ball could come off the clubface in any direction other than nearly perpendicular. It struck me as common sense. Though I realized a golf ball-golf club collision was not elastic, I didn't think that a ball could be "carried by the path" very much in the .000045 seconds the ball is "stuck" on the clubface. Not enough to determine where the ball went, anyway.
Eventually, my mind was changed. I'm sad to say that this change was not based on science but rather the fact that world-renowned instructors and players all said the same thing. "I aim my feet where I want to start the ball and I aim my clubface where I want the ball to go, then swing along the line of my feet" they said. During this phase I even went so far as to point out that billiards balls, collisions between which are almost as elastic as we see in real life, can be "thrown" off-line and be "carried" by other balls.
It turns out I should have trusted what I felt was common sense in the beginning: that the clubface has a much larger effect on the ball's initial path than any amount of "carrying" on the clubface by the swing path. Even though it's in another plane (vertical rather than horizontal), consider which direction a ball travels when you properly strike it with a descending blow. The ball launches upward, because the loft of the clubface is pointing that way.
Though The Physics of Golf shared the information years ago (the second edition is dated 1999). The information is available elsewhere too (like here and here - thanks to John Graham for those links). All of those works are fairly scientific, and though widely read and understood among the scientific component of the golf industry, the average golfer (and golf instructor) remained unaware.
The late 2000s marked a turning point in the battle of current, correct information versus "the way we've always told people to do it." In January, 2009 Trackman - makers of a popular launch monitor - publicly released information in their newsletter which shared the information in an accessible, easy to understand format. Again, while the scientific community - and a few instructors and golfers - knew this already, the Trackman newsletter was significant simply because of the easy digestibility.
From the January newsletter's article "The Secret of the Straight Shot" here (emphasis added):
The horizontal launch angle is determined by only two parameters, the club path and the face angle. As a rule of thumb, the horizontal launch angle is 15% determined by the club path and 85% determined by the face angle. For example, assume a club path of +6.7 degrees (6.7 degrees inside-out for a right-handed player) and a face angle of -1 degree (1 degree closed for a right-handed player). This would result in a horizontal launch angle of 0 degrees (ball starting at the target line).
In other words, you are saying that the face angle is by far the most dominating factor for the initial direction of the ball. Is this not in direct contradiction with the "Ball Flight Laws"?
Yes it is. According to the "old" ball flight laws, the initial direction of the ball (HLA) is 100% dictated by the club path. All the scientific people in the golf industry know that this is wrong, yet still a lot of PGA professionals use the incorrect 'old' ball flight laws in teaching. And many PGA organizations around the world do not teach their apprentice and member professionals according to the 'true' ball flight laws.Fredrik Tuxen, Trackman January 2009 Newsletter
The science gets a bit headier beyond that and the downward angle of attack and its effect on the "true swing path" is discussed. But the key piece is clear: roughly 85% of the ball's initial direction is determined by the clubface angle and only 15% is determined by the path.
These numbers vary little. You might think long drivers, who compress ("deform" is a better word) the bejeezus out of the golf ball, flip the ratio, but they actually push the numbers more towards the face, climbing into the low 90s. In fact, the ratio approaches 50/50 (but never gets below about 55/45) when you swing a wedge at a certain speed due to the contribution of the grooves with the path. Also, with the low loft, a putter can generate ratios approaching the mid to high 90% towards clubface contribution.
So How'd They Do It?
During a recent telecast at the Sony Open, Nick Faldo - a six-time major winner and one of the best golfers in the history of the game - shared this advice, captured in the screen shot you see here:
So how on earth did Nick Faldo shape the ball - and break par let alone win six majors - if he had the wrong information? The power of his subconscious mind. Science tells us that if Nick Faldo set up with his clubface at the tree in the picture above and his shoulders aimed just to the right at the escape route, he would either:
- return his clubface to the same angle as it was at address and swing along his shoulder line.
- subconsciously return the clubface open to (right of) where it was at address and swing even more inside-out than his shoulder alignment.
Shot #1 is what Nick said you should do. If Nick followed his own advice and performed #1, he'd hit the ball right into the tree. If Nick was on a golf course with no trees, the ball would start just right of the target and hook well left of it.
If Nick subconsciously manipulated both the clubface angle and the swing path to produce #2, he'd start the ball to the right of the tree and hook it back towards the target - the shot he wants to play.
What are you going to believe - science or Nick Faldo's feel? Even Nick Faldo's subconscious mind didn't trust his feel, favoring the reality of science (or the instincts of having been a great golfer for a long time) instead!
Ball Flight Laws and Their Effects on Teaching
Consider a student who's hitting a straight-fade or a straight-slice. A straight-fade starts straight at the target and then, for a right-handed golfer, peels off to the right.
If this golfer visits an instructor who believes the old ball flight laws, he's going to have the student trying to square up the clubface. After all, the instructor believes that the ball starts on the swing path, and then reacts based on the face. So the instructor will believe that the student's swing path is fine and that his clubface is open.
This instructor will spend a lot of time trying to get the student to "square up the club at impact" when he's already doing so! Best case scenario? The student starts hitting pulls. Hey, at least they won't slice…
The reality is that this student needs to work on his swing path. His clubface is already awfully close to square at impact - the ball is starting at the target. It's purely his outside-in swing path that's causing the fades or slices.
True Ball Flight Laws
One thing is not up for debate and never has been: a ball curves based on the clubface angle at impact relative to the swing path. A closed clubface relative to the swing path always draws/hooks and an open clubface relative to the swing path always fades/slices:
You can combine these three basic clubface positions with the three basic swing paths:
The combination of the two triplets result in a combination of nine possible ball flights:
This diagram demonstrates every possible shape a well-struck golf ball (we're not talking about tops and shanks here, people!) can have. The true ball flight laws tell us that a pull (B) is a combination of an over-the-top (outside-in) move with a closed clubface that matches the amount of outside-in swing path.
The true ball flight laws tell us that a push-draw (G) is a result of an open clubface with a swing path that's more inside-out than the clubface is open. For example, if the clubface is 3° open at impact but the swing path is 6° inside-out, the ball will start right (open clubface relative to the target) and curve left (closed clubface relative to the swing path).
How would the old ball flight laws tell us to hit a push-draw (G)? They'd tell us to swing in-to-out while keeping the clubface square to the target. Basically, they'd tell us to hit shot D. Ouch.
In the chart above you'll notice that the straight shots - B, E, and H - are italicized. These shots are each hit with a clubface square to the swing path and are the only shots on which the "old" and "true" ball flight laws agree.
I've also marked in bold the "good" shots: a pull-fade, a straight shot, and a push-draw. The straight shot is good for obvious reasons, but as you can see the pull-fade (C) and the push-draw (G) work because, though they start away from the target, they curve towards the target.
(Side note: That's not to say the other shots aren't good. Lee Trevino and Jack Nicklaus both played a push-fade. On my graph, that's shot (I), the farthest right. How could they win majors or even break par hitting that shot? Take the whole graph above and rotate it counter-clockwise (to the left). Imagine Lee Trevino: he aims his feet and swings his club 20° left, pushes the ball 10° right, and lets his fade take the ball the remaining 10° back to the target. That's how shot (I) can win a major - when you play for it.)
Where Do we Go from Here?
If you're like most golfers, having toiled under the old, incorrect ball flight laws, you may feel energized reading this. Perhaps you've been battling a persistent slice by trying to "release the club." It's a common suggestion, but if your ball starts at the target before slicing, you should have gathered that you need to work on your swing path, not your clubface angle at impact. That's even more important if the ball starts left before slicing two fairways over.
Armed with the proper knowledge, you're going to be amazed at how often you hear advice based on the old, incorrect ball flight laws, and from whom you hear it. Magazines, television, respected teachers, and accomplished players will all dish out advice that's potentially damaging to your golf game because it's based on the "old" laws.
The ball flight doesn't lie. Now that you know how to read it, you can spend your time working on the right things.
Photo Credits: Black and White Illustrations: Unknown Origin; Color Diagram, Screen Capture © The Sand Trap .com; Video © Golf Channel.