The physics lesson every golfer needs, explained simply

Golf Digest senior writer Alex Myers is on a one-year mission to see how good he can get at golf through daily training, practice and playing. Read more from his “Late Scratch?” series here.

Late in the final round of a buddies trip to Hilton Head last fall, I had the lead, but I was suddenly battling both a talented 18-handicap named Chris Shapoff and a mean case of the hooks. Even swings that felt good at impact were snapping so far left at the George Fazio Course at Palmetto Dunes that I did something crazy on the 18th tee: aim well right toward the 10th fairway. My golf ball stayed in play—albeit, way right—and I wound up making a four-footer for bogey to secure our group’s green belt. After limping home to victory, I was more relieved than happy—and I knew I needed to fix that left miss.

But as I’d find out a couple months later on an indoor simulator screen at Quaker Ridge Golf Club, I had no idea how.

Thankfully, head pro Mario Guerra was able to quickly diagnose the problem. The steps to solving it actually started with a golf physics lesson. And what I learned that day can help any golfer start on their way to becoming a ball-flight master.

In my first meeting with Mario, one of Golf Digest's Best In State Instructors for New York, I told him about my big miss and that I believed it was coming from an over-the-top move. But after hitting just a few shots, Mario showed me that thinking was farther off than some of those drives on my trip.

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I was stunned to learn I was actually doing the opposite of an out-to-in swing. I was swinging in-to-out at impact. And in dramatic fashion. Looks—and feels—can be deceiving, but simulators don't lie.

As Mario explained, where the golf ball goes is primarily caused by a relationship between the club path angle (which causes curvature) and the club face angle (which creates the initial direction of the ball) so it’s important to focus on those two numbers. (This is assuming center-ish face contact because hitting a ball off the heel or the toe can cause its own set of problems.) A few basics:

• A positive club path angle means an in-to-out swing.
• A negative club path means an out-to-in swing.
• A positive face angle means the club is open to the target at impact.
• A negativeface angle means the club is closed to the target at impact.

There’s also face-to-path, but that can simply be figured out by the difference between the two on each swing (The bigger the difference, the bigger the curve). This can be a lot to digest, but we'll explain more as we go along. In the meantime, here’s a handy chart from HackMotion that explains the golf ball flight laws more:

I had heard about golf ball flight laws before. In fact, I’m sure I’ve had at least a couple of instructors attempt to explain them to me. But with Mario, the lesson stuck. And it was an eye-opening experience.

Mario was able to see my problem so quickly because my club path numbers were jumping off the screen—and not in a good way. As Mario pointed out, I had an overly positive path (in-to-out) to the target that was getting up to near eight degrees on some swings. Here’s me hitting a shot with the numbers from the previous swing still up there. I’ve highlighted the club path, which was an extreme 7.2 (!) in this case.

When it came to club face, I was always closed to the path, but to varying degrees. The times where the angles almost matched up, produced a nice draw, but when I got the face closed to the target at impact (negative), the ball would start left and go farther left due to the high amount of right-to-left spin I was imparting on it thanks to my positive path. Hence, those dreaded hooks.

But here’s where Mario explained why he believes club path is much more important than club face. Even without getting my club face exactly square to the target at impact, my misses were going to be so much smaller with a more neutral club path putting less sidespin on the ball (More on that in a bit). So what were we going to do about it?

Thinking I was coming over the top earlier in the year, I began to do a drill in which I’d purposely take the club back to the outside and then overly loop it to the inside on the downswing (Think: Jim Furyk). When timed well, the move produced powerful draws. The problem was it was hard to time and now it had become ingrained.

So now I needed to feel the opposite of what I had done earlier in the year when I was trying that inside loop drill to produce an in-to-out swing path. Mario had me start swinging left intentionally.

At first, this felt weird and like I was swinging way over the top, but the swing path numbers instantly showed I was swinging on a more neutral (Mario counts anything between -2 and +2 as pretty neutral) path. Again, looks and feels can be deceiving, but those numbers tell the truth.

Once you understand how the golf ball flight laws work, you realize there are certain combinations that work. Like, I could now hit fades even with a slightly closed club face if that face was open in relation to a negative club path. Confused? Well, for instance, if you have a -1 club path and a -.5 club face, your face-to-path is actually .5. And a positive face-to-path like that causes a fade/slice while a negative face-to-path promotes a draw/hook.

Or, I could hit nice draws with a less positive path provided the face remained closed to that path. If you’re still confused (I don’t blame you), here’s a video that dives deeper into understanding these numbers:

Anyway, Mario’s belief that I could get myself to swing the club on a more neutral path was proven by the numbers. And, fortunately, it turned out to be a pretty quick fix. Look at this beauty!

That's a club path angle of 1.0 (slightly positive) with a perfectly neutral face to the target (0.0 degrees) that results in a -1.0 face-to-path or a slight draw that winds up almost dead straight at my target. My earlier swings with a positive path angle in the 7s would have produced a much more negative face-to-path and, thus, a shot finishing much farther to the left.

I was initially worried that swinging more left would make my clubface close even more, but Mario also explained that with a more neutral path, it’s harder for that to happen. Grab a club and see for yourself. If you swing left, it feels awkward closing the face. Instead, the face naturally wants to open to offset the club path.

To emphasize that point, Mario told me a story that comes from famed instructor Jim Hardy involving one of his students, Chris Tidland, and the final hole of a Korn Ferry Tour event. Tidland wasn’t going to win, but there was a nice check on the line if he could make par on a closing par 4 with water left. As the story goes, Tidland’s caddie pointed out a conservative target down the right side of the fairway, but Tidland replied by saying he was going to swing as if he was going to hit his golf ball through the window of a car on display in the pond to the left. The result? A big fade that found the middle of the fairway because he created an overly left swing path while keeping the face open to that negative path.

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Turns out, I should have been swinging toward the danger and not away from it on my trip. Instead, I was like a right-handed slicer who just keeps aiming more left and making the problem worse. But armed with this new knowledge, I'll be better able to at least figure out what’s going wrong the next time I find myself in a similar situation.

I was never much for simulators, but now that I understand the numbers better thanks to Mario, I’m hooked. At a company Christmas party at Five Iron Golf in NYC, I geeked out with several co-workers over seeing some neutral swing path figures. When a friend sent a screenshot of a good drive he hit, I complimented him, but added that he just has to work on getting his attack angle more positive (More on that another time!). And I now routinely bring my Stack System Radar with me when I go to the range to measure club and ball speed. Heck, I've even got my seven-year-old into the numbers.

Who knew math could be so much fun?! To be clear, there are a lot more things to look at than just path and face angles, but that was a really good start for me—especially because my path was getting really extreme and I didn't even realize it. You might be really extreme the other way with a negative path and need to do the opposite. You also might want to work the ball more and thus have a pronounced path in one direction or the other (You still wouldn't want to be in the 7s like I was for some shots).

But for me, I’m taking Mario’s advice and trying to keep the path neutral in order to hit the ball straighter. Specifically, I’m working on eliminating that (big) left miss by swinging more left to promote a fade. And as a result, my dispersion pattern during practice sessions has gotten a lot tighter.

It’s amazing what technology like Trackman, Foresight and Rapsodo can do. It’s even more amazing what you can learn from just analyzing the numbers. So, get in a simulator or visit a range with this kind of technology and start actually understanding the real reasons why your shots end up where they do. Then you can more smartly work on where you want them to go.

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