Low Net

This speed training program led to a U.S. Open title. It’s also worked wonders for me

December 16, 2023

Matt Fitzpatrick and I had the same objective: We both wanted to get longer. It's just that Fitzpatrick was in search of a major title, and I'm still looking to break 80.

While my clubhead speed in the past might have technically slotted in the average range, I tended to slow down when my confidence wavered, or in some misguided pursuit of “solid contact.” Watch the video I made with PGA Tour pro Joel Dahmen last year and you know why I anticipated a seamless transition to old man golf. Even in my 40s, I already swung like someone’s grandfather.

When I signed up for the Stack System, the speed training program that Fitzpatrick credited with transforming his game en route to winning the 2022 U.S. Open, I still harbored fears that swinging harder would come at the expense of control. I have since learned this was wrong. After completing my first speed-training program, it’s apparent my mistake wasn’t targeting a few more miles an hour of clubhead speed. It might have been setting my sights too low.

What is overload/underload training?

On the surface, the Stack System isn’t complicated. A typical program consists of making hundreds of golf swings over several weeks using a shaft on which you “stack” an assortment of ring-shaped weights. There are other speed-training devices that also emphasize overloading weight, the premise being that by swinging heavier loads, your body adapts and learns to swing faster when the weight is off. But to me, the hook of the Stack is two additional elements. One is a swing-speed radar required to measure the power of each swing. The other is the app that tailors a program specifically for you and provides an ongoing gauge of your progress.


This feedback loop is the program’s addictive feature, even when making one swing to the next. Within a 25-minute Stack session, you begin to understand what positions generate speed and where there is still inefficiency. And you only want to keep going.

Speed training raises your ceiling

According to the Stack founder, Sasho Mackenzie, a Ph.D in kinesiology at St. Francis Xavier University in Nova Scotia, this was by design.

“You start to self explore,” Mackenzie said by phone. “You make a swing, you see 95 mph. And you're like well, you know, maybe I'll try to increase my hip rotation. ‘Oh, look, there's a 97.’ Just in an effort to make that number go up, you start to find and improve mechanics.”

The Stack is also strategic in acknowledging and encouraging progress. When you record a personal-best speed, a crowd applauds. At the end of each session you can see your progress in measurements such as “eSpeed”, which the Stack program uses to estimate how fast you could swing your driver; and your “Distance Potential,” which measures how that could equate to yardage on a course. For both, my gains were notable: my eSpeed, after starting in the high 80s, has registered at 104 mph, and my distance potential jumped from 241 to 289 yards.

But does this actually work hitting a golf ball?

Remember, though, that the Stack involves mere air swings—I usually trained in bare feet in my bedroom—so I was still skeptical about what it would mean with a ball in front of me. For years I equated swinging hard with only exacerbating my assorted swing flaws. If I come in too steep from the top, for instance, I worried a faster swing would only send a ball farther off line. In fact, the opposite has been true, because swinging harder also has taught me how to sequence the swing properly—loading my right side more, before powering through to the left. In my first session hitting balls on a simulator, I was hitting drives some 30 to 40 yards farther than my best drives in the heart of the summer. Most importantly, my bad drives are all markedly better as well.

“With the avid golfer, someone that plays two or three times a week, they've worked themselves into a very constrained, safe swing,” Mackenzie said. “We just get into this kind of safe zone where we think it's optimal for finding fairways, but It's really not.”

Speed training raises your floor, too

As I noted to Mackenzie, the Stack has helped increase not only my ability to swing faster, but my willingness as well. It’s also raised my “floor” where a somewhat controlled swing now is still faster than anything that came before.

“The fundamental philosophy with the Stack is to take your maximum speed and increase it so that you can actually play at a lower percentage of your max effort,” Mackenzie said.

Will the Stack work for everyone?

While it’s fair to assume the Stack would help most golfers, I should note a few areas that expedited my progress. For starters, it helps that I am already uniquely fixated on improving my golf swing, as my friends know, so I didn’t need much prodding to carve out the 25 minutes every other day that a typical Stack session requires.

Yet for someone so obsessed, I also had a swing that was woefully inefficient. I am more than 6 feet tall but it’s only because of the Stack that I’ve started to effectively engage my lower body.

After reviewing my swing and my progress, Mackenzie says I have “a lot of potential,” which sounds like a compliment, but mostly was his way of saying I’ve still got a long way to go (his tip: I need to use more ground force for leverage). That part I don’t mind. After completing my first Foundation program, the Stack’s algorithm has recommended I start its “Full Speed Spectrum”. It’s 24 sessions that should carry me through the rest of winter. I’ve never been so excited to get back to work.

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