Golf, Scientifically

Professor Robert Grober was a postdoctoral researcher at the AT&T Bell Labs when he first put a sensor on a golf club. That was sixteen years ago. Today, his electronically enabled intelligent golf club, Sonic Golf, has revolutionized the way golf is learned and practiced.

It all started as a hobby. As a golf enthusiast looking for ways to improve his game, Dr. Grober would put sensors—originally meant to measure vibrations of tables on his golf club—on his clubs in order to understand the factors affecting the golf swing. The concept was not new; articles on applying physics to golf swings had been around since the 1960s. But Grober approached this problem differently from those before. Grober’s aim was not only to learn the governing science and use it to improve the game but also to make the entire process measurable. ‘[So far] Golf has been taught through video analysis. This is only statics. The new approach is to teach dynamics,’ Dr. Grober said, outlining his fundamental strategy. Grober’s solution was to make the golf swing audible by co-relating the speed of the swing with the pitch and volume of an orchestrated sound. The idea was straight forward: you listen to the swing, compare it to the sound of those of professional golfers, and try to emulate it.

The effectiveness of his regime lies in the mechanics of the different qualities of swings. The swing varies from golfer to golfer, but all have underlying similarities that can be used to classify them into those of professionals and those of amateurs. The speed of a seasoned swing increases rapidly as the club rises, becomes very slow at the transition from upswing to downswing, and peaks when the club strikes the ball. In audible terms, this corresponds to a loud note at the start, a quiet note at the transition, and an upsurge of sound at the downswing. Further, unlike those of amateur golfers, the swing of a professional golfer is symmetrical; the motion of the upswing and downswing is similar; consequently, the sound they produce is symmetrical too.

Grober argues that the human body acts like an oscillating load on a spring whose performance can be optimized through resonance. By using his or her body resonantly, the proficient golfer gets maximum motion with minimal input. Built upon this idea, Sonic Golf allows golfers to achieve the required resonance and symmetry simply by moving the club back and forth and fine tuning effectively.

The results of the device have been astounding. The Sonic Golf’s System-1 prototype was first used at the Stanford St. Jude Championship in June 2008 by Vijay Singh; he went on to incorporate it into his routine practices for later events. Regular use of the device enhanced his performance dramatically as he, after losing for 17 straight months, went on to win four PGA events. His streak culminated in the 2008 Fedex Cup Victory and a top spot on the 2008 PGA Tour Money List. The device is also used among the Yale Golf Team. As a testament to the success of his technique, Dr. Grober received the Golf Magazine Innovator Award in 2008. The immediate success of his prototype drove him to found Sonic Golf, Inc.

While professional and beginner editions of System-1 have been on the market since December 2008, Dr. Grober is advancing his research further to understand the golf swing and explore other applications of the Sonic Golf audio biofeedback technology. In recent studies analyzing the motion of a golf club, Grober uses two strategically placed accelerometers to measure acceleration along the axis of the shaft. The sensors decompose the motion of the shaft into two parts: the differential mode and the common mode. The differential mode indicates the centripetal acceleration processed to study tempo, rhythm, and timing, while the common mode indicates the acceleration of hands.

Such simple experiments offer deeper insight into the science of swing and demonstrate the applicability of the technique to other sports. Although the technology is applicable to tennis and baseball, Grober says production decisions will be largely guided by market size and conditions. Further, in collaboration with researchers at the Yale School of Medicine, he is investigating the possibilities of using audio biofeedback to help patients perfect their walking and motor functions. He is also transforming his engineering lab to accommodate the swiftly expanding research project.

While Grober studies the physics of golf in the lab, he makes sure that he shares his work with the Yale student body. ENAS140b, Physics of the Game of Golf, a highly rated class on the Open Course Information server, aims to provide students an opportunity to apply their knowledge of physics and mathematics to understand the fundamentals of golf and use them to improve their game. It covers topics ranging from swing biomechanics to golf ball aerodynamics. When asked about the importance of giving back to the students at the university that has supported his work, Grober says, “Technology drives society…Our economies are driven by technological innovation. You need to define the direction for the world. You have to generate new ideas.”