The next innovation in golf learning could come to your wrist (and your chest, back and hips) | Golf news and tour information

Suggest to struggling golfers that they should take lessons, and you’re likely to hear one of two responses: They’re too expensive or there’s not enough time. This is especially true for people who don’t belong to a private club with access to great instructors and a pristine practice range, and don’t have countless hours to grind without feedback.

Sang Kim, founder and CEO of 4D Motion Sports, created a product aimed at solving the problems that keep golfers from reaching their peak performance. Kim has been a serial entrepreneur and inventor for the past quarter-century, working primarily on internet startups. He needed a break after his startup was acquired by a Fortune 500 company, so he started playing golf full-time.

“The first thing that happened was I just couldn’t putt,” Kim said. “One day I made three putts 12, 13 times and I said, ‘There’s got to be a better way.’”

Kim, a self-described “scientist,” realized that all he needed was a tiny fraction of a golf ball to sink more putts. He put on his inventor’s hat, went home, grabbed his son, and they took a hacksaw and started experimenting with both sides of the ball. They came up with the PutterWheel, a product that Kim later pitched to two “Shark Tank” judges in a competition at the ASI convention, which he won.

“We were just mobbed,” he said. “Then we signed with Dick’s (Sporting Goods), we were in 750 stores. That kind of got me into the (golf) business.”

That’s when Kim realized he really wanted to fix his entire swing. He knew that while there were many great golf instructors out there, they couldn’t be with you all the time and rarely on the course. Using his technical background, he wanted to create a system that could measure, analyze, and coach your swing anytime, anywhere.

At the time, 3D body capture was available, but Kim saw that it was way too expensive for the average golfer. He wanted to create something that was affordable, put it on mobile devices, and make it super fast. That’s when he came up with 4D Motion, a passion project that’s been 12 years in the making and that Kim is ready to launch for consumers.

“It’s the hardest thing I’ve ever worked on,” he said. “If I knew it would take me over a decade, I’m not sure I would have ever started. But now I think we have a product that I can honestly say has to make people better.”

When I first tried out the 4D Motion Vest and saw the instant feedback on my Apple Watch, I was surprised because I’m the type who wants to know less about my swing when things are going well (surprisingly, they are now). “That’s the goal,” Kim says. The prototype vest, which you wear under your golf tee, has three sensors: one between your shoulder blades, one on the sacrum at the bottom of your hips, and one on your chest that acts as a gateway to a phone app that picks up everything from alignment, shoulder plane, pelvic speed, spine angle, and more. After my first swing at the range, it took three seconds for all of those data points to show up in the 4D Motion app, which showed that I had overshot a bit and that I had pulled a bit too early, leading to a pull. Those two data points were in red, signaling what I had done wrong. Alignment, stance, rotation, and shoulder plane were all in green, signaling that they were all in good shape. Easy to understand.

On my next swing I tried to swing more from the inside to the outside, hoping to eliminate the over-the-top movement that can lead to dead pulls or mega slices. After hitting the ball I felt like I had fixed the problem. The data reflected that. That euphoric feeling was short-lived, however, when Kim showed me that I had a low loss of stance score. Back to work.

You don’t even have to leave your house or have a club in your hands to work on proper swing positions. Put on a vest in your living room, open the app on your phone and simply go to your setup and make a turn. The sensors will detect the movements of your torso and hips, and your model in the app will turn green and make a buzzing sound when you’re in the right position.

Of course, using a product on the range or at home can only get you so far. Kim’s product stands out because it tells you exactly what you’re doing differently on the range and the course, allowing you to identify the factors that are keeping you from making your best swing when you need it most. In a recent experiment with a low-handicap player, every swing he made on the range was on the green in the app. Then he went out to play six holes, and the app revealed a number of flaws, including early extension and a flat arm plane.

“You get tense, you tighten up. You don’t rotate properly,” Kim said. “His biggest flaw was his flat arm plane. He never knew that. Now he does. With this system, you can even do a practice swing and see if you’ve fixed it or not.”

The vest is already used by top competitors and their instructors. Kim has also made inroads with Major League Baseball teams—former Nationals batting coach Kevin Long serves on 4D Motion’s advisory board—and has been used by the U.S. Figure Skating team, where he developed an injury-prevention system that uses machine learning to identify jumps during training and detect fatigue that could lead to injury.

You’ll be able to get your hands on one soon, too. Kim says they’re launching a Kickstarter campaign for the product because they need financial support to produce it. As for pricing, Kim says they’ll offer a variety of packages, but the final price will be in the $600-$900 range (Editor’s note: Golf Digest is a minority partner with an even more affordable option, the Mustard Golf app, which provides AI-generated feedback and instruction on videos of your swings).

“My goal is to make it affordable. If you can afford a new driver or putter these days, you can afford it,” Kim said. “And I think you’ll get a much bigger improvement from that than you would from a new driver.”

The product has already gone through several updates and is faster than I first used it. Now you will be able to quickly add notes and comments, noting what specifically went wrong or right with each swing and you will be able to click on that swing and see what you have saved later.

“That’s when you can really tell the difference,” said Jim Beadle, director of business development for 4D Motion Sports and a golf instructor himself. “OK, good shot, bad shot, high draw, high slice, punch. You can really start to tell the difference between every shot I’ve ever played on this course.”

The big picture, of course, can be overwhelming. That’s why Kim is revealing only a fraction of the data and technology they have at their disposal for now. As time goes on, users will be able to unlock more and more data points that will be useful to them. Simplifying the product for the consumer was paramount.

“I wanted to help people like me,” says Kim, who has a single-digit handicap and is always looking to improve, like we all are. “That’s what this product is all about. Maybe you can’t afford lessons, maybe you don’t have time. Maybe you like your swing on the range, but you want to know what’s wrong with your swing on the course, where it counts.

“Golf is one of the few sports where — imagine meeting someone and saying, ‘Oh, you play the piano? How long have you been doing it?’ And they say, ’30 years.’ And they go out and play ‘Chopsticks.’ That would never happen. But in golf, you meet someone who’s been playing for 30 years and still has a 28 handicap. Something’s wrong there and I’m trying to fix it.”