This Former Apple Product Manager Wants To Fix Your Swing

Statistics and video footage have long been thought the only answer to swing coaching in baseball, tennis, and golf. But Zepp Labs has developed a new data-driven solution.

This Former Apple Product Manager Wants To Fix Your Swing

With regulators cracking down on performance-enhancing supplements, athletes are turning increasingly toward “quantified self” devices to give themselves an edge over the competition.


But most of these devices–the Nike FuelBand, Fitbit or countless iPhone apps–are built for runners or cyclists, whose bodies are in motion during play. Baseball, tennis, and golf players need something that measures the motion of their bat or club, not their own bodies.

A company called Zepp, headed by Jason Fass, a former product manager at Apple who oversaw the MacBook line, has built a small sensor about the size of a Starburst doesn’t just solve the problem, it opens up an entire new world of performance metrics to people at all levels of sport.

Bringing Sports Metrics Home

In professional sports, metrics are everything. Aside from rare “intangibles guys,” only quantifiable statistical measures count. After all, production is why they pay pros the big bucks. To date though, technology has not caught up to front office data analysis.

“The Giants–and I only use the Giants because they’re in our backyard–have this amazing video system where there’s cameras in the dugout, the outfield, home plate, and even a camera above when they’re in the cage, but even Buster Posey has to leave the field, go into the clubhouse and approach the video booth like, ‘hey can you show me that at-bat? I gotta see that swing.’ Now? They can see immediately, ’67 miles per hour? Speed it up!’,” Fass says.

How The Zepp Sensor Works

At the very top of their software stack, Zepp placed what they call their pattern recognition layer, or the “sport specific layer.” The app then looks for general motion patterns that have specific backswing and forewing components. In fact, the baseball and tennis apps require impact to identify a swing. “If you’re wearing the sensor and you wave to your buddies, it’s not going to register,” Fass says.

Because they’re dealing with high-speed sports, the algorithms change based on what game the user is playing. In tennis, as Fass explains, “The algorithms are actually designed to recognize what a forehand is, what a backhand is, and track the face of the racquet on impact to determine spin.”


The technology can be used for live game or match tracking, too. It captures everything. The sensor puts out 1,000 data points a second, a daunting amount of information for the average athlete to process.

“The trick is what data we’re actually gonna listen to, process, capture and show the user. Really, we’re trying to keep the technology out of the way and give people only the data that’s useful,” Fass says.

Game Changer: What The Zepp Sensor Means

And while more features will be applicable to little league and high school players at the outset, Zepp discovered one feature of particular interest to pros conducting batting practice with San Francisco Giants minor leaguers: bat speed.

“Pros know what feels right,” says Fass, “and Zepp’s program allows hitters to star swings that feel good and look at them later. One of the biggest things for pros is time in the strike zone and time to zone. They might be swinging 90mph and that time in the zone might be .027 sec, but the percentage of time they spend in the zone during their swing is really important.”

How Zepp Made The Hardware

Developed by a team of engineers who worked on international space programs, Zepp’s “rocket scientists” used video, high-speed cameras, and physical examples of players at varying levels to establish ground truth. Unlike your iPhone, the Zepp sensor has two accelerometers–one for high speed and one for low speed. “If Nike tried to do the same thing with FuelBand, a single accelerometer and nothing else,” says Fass, they’d be using “a 2-D solution to a 3-D problem.”

The company’s first product, GolfSense, was quite similar to their new product, only golf-specific. Moving forward, the company wanted to broaden their appeal, so they added baseball and tennis. But they only made one sensor. The only way in which the new technology differs sport to sport is the sport-specific mounts (available separately) and apps (free). On top of that, the Zepp team designed everything from sensor to charger to packaging.


Performance Enhancer: The Zepp Sensor Makes You Better

“People assume, ‘oh that’s not legal,’ but you’re not altering your bat–you can put things on your bat that force you to choke up,” says Fass. “In the PGA, it’s not illegal unless you were to look at the data during your round. In tennis, I don’t believe there’s any rule prohibiting use.”

But even if Zepp’s apps aren’t “legal” for professionals in-game, the tool still has undeniable value to players of all ages and experience levels. The social media aspect alone could reshape the way coaches and scouts understand statistics, not just by providing new measures, but also by measuring everything.

“People can set up groups and compare numbers and stats, little league teams can track stats, and such. Social content will change based on our audience, which is where we see tremendous potential for this data, whether you’re a coach, a nutritionist, a scout, you’re getting access to all this data and that is really cool,” Fass says.

Where Zepp Is Headed

And people are itching for the solution. Users are adding 500,000 swings a month to the database, and not just the swings themselves. They’re also adding their age, height, clubs, bats, their clubs’ specs. And all of the data is available for users online. But where Zepp truly sets itself apart is what they’re doing with all that information: building coaching strategies into the apps themselves.

As Fass says, “We want to tell our users, ‘Hey, you should practice with your 7 iron, you haven’t used it in a long time,’ or, ‘All your buddies are using this club and coming through 5mph faster. Give it a shot.’” And soon, users will be able to use their phone as an additional sensor measuring hip rotation for even greater accuracy.

Swing away.

About the author

Matt Hartigan writes about sports technology for Co.Labs. He graduated from the University of Southern California in 2006 where he studied English, Psychology, Fine Arts and spectatorship