Babolat tennis racket, 94Fifty Smart basketball: Can high-tech gadgets improve your game?

Can This Gadget Turn You Into Rajon Rondo?

Can This Gadget Turn You Into Rajon Rondo?

Innovation, the Internet, gadgets, and more.
March 17 2014 10:45 AM


New high-tech sports gadgets that promise to improve your game.

There's a chip in that ball.

Photo by Slate

I’ve made peace with the notion that I’ll never run point for the Celts in the NBA finals, shoot a 63 on Sunday at Augusta, or bagel Rafa in straight sets on the Roland Garros clay. I’ll forever be a sad-to-middling weekend athlete. And yet I like to imagine that I still have potential for improvement.

Seth Stevenson Seth Stevenson

Seth Stevenson is a frequent contributor to Slate. He is the author of Grounded: A Down to Earth Journey Around the World.

I’m not alone. There are millions of plodding, athletically challenged, wannabe jocks out there scouring YouTube clips for coaching tips, enrolling in lessons from local pros, and buying bizarre and, frankly, embarrassing instructional aids.

The latest trend in sporty self-improvement: sensors that analyze your physical form and give you instant feedback. A wave of new consumer devices—packed with teensy accelerometers, gyroscopes, and Bluetooth transmitters—promises to track the speed of your golf swing, the shape of your tennis stroke, and the backspin on your jump shot.


I tested out a few of these products to see if they’d boost my skills. Could technology help me morph into a beast in my weekly hoops game? Give me the skills to crush my regular tennis partner? Shave precious strokes off my disappointing golf scores?

One must acknowledge a fundamental weakness with these sports sensors: Simply knowing, say, how fast you swing your 7-iron does not at all translate into hitting a golf ball straight and true. Improving in an athletic endeavor requires a collection of tiny, subtle adjustments. Tweaks to your stance, rhythm, balance, alignment, fluidity. Only a trained eye will be able to watch the whole motion and identify its weak link.

Still, while they won’t immediately launch you onto the front of a Wheaties box, some of these sensor products do offer useful functions. Herewith, my rankings on the country club ladder, ordered from worst to first:



There’s something pleasingly sci-fi about a tennis racket with a mini-USB port hidden in its handle. Pop open the Babolat’s butt cap and it’s hard not to feel you’re peering into the future of sports. The promise is obvious: Play a set or two, plug the racket into your laptop, and download an instant, detailed analysis of your performance. I couldn’t wait to take this thing out for a spin at Midtown Tennis.

Sadly, the reality was far less fun. Despite repeated efforts, I couldn’t get this thing to work. Scads of online reviews confirmed my suspicions: The Babolat is buggy. Though my computer recognized the racket, it failed to locate any data from my on-court sessions. I called up Babolat, which acknowledged the bug, promised me it’s working on a long-term fix, and gave me instructions for a short-term workaround. I followed those instructions closely, yet the racket still failed.

Even if the Babolat had performed smoothly, I see a core problem with its model. What if you prefer a racket with a larger or smaller head size? What if you’d like to be able to swap in, mid-set, a backup racket with a different string tension? Or what if, heaven forbid, you break a string? Because the sensor is buried within the handle, and the handle is nontransferable, you’re forced to play with this particular $400 racket if you wish to record your data. Seems like a fatal flaw. And one that could be easily obviated—as demonstrated by our next competitor:


The Zepp can be used—in tandem with various mounting accessories—to analyze a tennis shot, a baseball swing, or a golf stroke. I first tried it out with tennis. It slips into a rubbery housing that stretches over the butt of any racket, even a cheap one. The sensor doesn’t get in the way of your grip, so I soon forgot it was there.

Unlike the Babolat Play, the Zepp managed to give me some actual results. I easily paired it with my phone using Bluetooth. The Zepp tennis app immediately downloaded a snapshot of the set I’d played against a pal.

There were interesting nuggets in the data. The Zepp tallied 254 shots over the hour I was on the court, of which 58 percent were forehands and 35 percent were backhands. It showed that I struck my groundstrokes with consistent power over the course of the set, while my serve lost oomph as I got tired toward the end and my shoulder grew grumpy.

But I wasn’t convinced the portrait being painted was totally accurate. The Zepp told me that 47 percent of my forehands were sliced, which couldn’t be right—I know I hit all but a few of these strokes either flat or with topspin. More damning, it claimed I hit a total of only 16 serves over the course of the entire set, which is simply impossible. I hit nearly that many in a single long game that featured multiple deuces. When I asked Zepp about this issue, the company acknowledged the flaw and said it’s working on better serve recognition.


Even if this data were sound, I’m not sure how useful it would be. OK, let’s say I really did hit 58 percent forehands. Does that mean I’m stepping around my backhands to avoid them? Or does it just mean that my right-handed opponent was hitting mostly crosscourt? Would I be strategically better off if I tried to hit more backhands, or not? The Zepp is silent on these matters.

Over at the Chelsea Piers driving range, I slipped the Zepp into a mount that lets you affix it to your golf glove. Then I hit a slew of balls, alternating between a driver and a 7-iron. The sensor tells you your club speed (mine ranged from 77 mph up to 103 mph as I cycled through differing levels of frustration and physical anger) and compares the tempo of your backswing to your follow through (mine mostly hovered around 2.5:1, meaning it took me 2.5 times longer to draw the club back than to swing it forward).

It also creates a beautiful animation of your swing, which you can rotate to view from different angles. This was the most intriguing feedback for me, as it let me compare the plane of my swing to the ideal plane that Zepp suggests. According to the sensor, I swing too horizontally (like a merry-go-round) and should get more vertical (like a Ferris wheel). By watching the animated playback of my swing immediately after each drive, I nudged myself toward a more upright swing plane. The problem: These more vertical swings produced terrible results—wicked slices that veered off my club into the side netting of the driving range.

Perhaps a seasoned golfer with good form and self-knowledge could use the Zepp to experiment with nuanced adjustments. But for a duffer like me (personal best round: 106), the Zepp’s feedback was like sparks thrown on damp kindling. I didn’t know how to use its suggestions, and I wanted the help of a golf pro to spot basic flaws in my form. Perhaps in concert with some human instruction, the Zepp could be a handy device. The coach could point out my best swing, recording its data on the Zepp, and then I could check future swings against that ideal when I practiced alone. But by itself the Zepp wasn’t enough to improve my game.


3Bays GSA Pro, $181.30.

This slick little sensor plugs into the hole in the butt of all standard golf clubs. It didn’t interfere with my grip. And to me, mounting the device to a fixed spot on the club seemed likely to offer more consistent results than the Zepp approach, in which you wear the sensor on your hand and then tell the device the approximate angle of your grip.

I loved the ability to follow through on a drive, step over to my phone, and immediately watch my swing recreated in vivid animation—with stats on my club head speed, impact force, tempo, and so forth. The GSA Pro seemed trustworthy: When I purposely sped up or slowed down my swing, or changed its arc, the device recognized the difference. My favorite feature: The sensor informed me I was almost always hitting the ball with the club face too open (instead of square on) and that my swing path was too outside the ball. This is genuinely useful and actionable knowledge. But again, putting it into play would be much easier if I had a pro by my side to coach me through the necessary adjustments, instead of me just guessing how best to achieve them.



I had very high hopes for the 94Fifty, which embeds sensor technology and a Bluetooth transmitter inside a standard basketball. The ball can measure how fast you dribble, how hard you dribble, how quickly you release a shot after receiving a pass, the arc of that shot, and the backspin on the ball each time you shoot it. You can’t use the 94Fifty during a game (the ball won’t know which player did what, and it can’t automatically switch between analyzing ball handling and shooting), but the accompanying app is perfectly designed to lead you through individual drills. I tried it out with some friends before our weekly Wednesday evening game in an Upper West Side elementary school.

The sensor seems highly accurate, as best I could tell. It tallied my dribbles, told me the precise revolutions per minute on my jump shot, and recognized whether that shot more closely resembled a rainbow or a clothesline. As a diagnostic exercise, this seemed hugely useful: It was evident that everybody in my game was dribbling the ball with inadequate force, shooting at too flat an angle, and not launching the ball with enough backspin—all of which rang true. (Further proof: The better shooters in my game had the highest arcs and the most spin, though still not enough.)

I imagine the 94Fifty could be an ideal birthday gift for a hoops-mad middle school kid—assuming the kid can be trusted not to lose a $250 piece of equipment. The app walks you through drills, ramping up the difficulty level as you advance. Leave the tyke alone in a driveway with a backboard and he or she will be entertained for hours, improving skills and trying to beat personal bests.

As for me, given that I can no longer spend endless afternoons honing my jump shot, I think I’d be better off spending that coin on a couple of shooting lessons. That’s true with all these other devices, as well: Gadgets like these just aren’t the best way to improve your game. While there’s clear potential in this field, for now you’d be far better off directing your cash toward a few in-person tutorials from the nearest expert. (Or, if you insist on hiring only the finest instructors—geography be danged—you might spring for some remote analysis from a heralded pro, aided by a  video app that allows for on-screen telestration. Which, by the way, seems like a no-brainer use of tech in sports, akin to receiving guitar lessons over Skype from a brilliant music teacher who happens to live in another state.)

Still, I might just be tempted to buy one of these 94Fifty balls for myself. I have no doubt the mere repetition of the drills would improve my ball-handling skills, at the very least. Though sadly I’d still be 5-foot-11, with the vertical leap of a refrigerator and the coordination of a drunken, three-legged dairy cow. Rajon Rondo need not fear.