Sak, a certified tennis coach and lifelong tennis player, teamed up with engineer Sergey Feingold to co-found Shot Stats, to create smart tennis rackets that collect and deliver instantaneous stats on a player's swing.
The start-up considers the device a game-changer and calls it Challenger. It looks a lot like a tennis dampener and snaps into the strings near the base of a racket. It includes a speaker and touchscreen face that gathers information like racket speed, time on the court, the number and type of shots taken and the amount and type of spin applied to the ball.
The device is Bluetooth compatible, which means users can sync their data directly to a smartphone. Sak said the app, which works on Android and iOS, will not only reveal data points, but will also make recommendations, offer tips and drills on how to improve technique and strategy while on the court.
The co-founders told CNBC they plan to sell the device online for $199, and they are in talks with major tennis retailers and racket manufacturers to bundle the device with rackets. The founders expect to bring the tennis technology to market in early 2016.
Future plans include software upgrades that will enable devices being used on the same court to connect to each other and collect data on players swinging from both sides of the net.