YOU GET A LOT OF RACKET FROM THE MAGNIFICENT GREEN TENNIS MACHINE

It only takes a few minutes of conversation with James L. Cox to understand why this crew-cut ex-boxer and one-time member of the Junior Davis Cup squad has turned himself into a corporation. Conglomerate is perhaps a more accurate term. Cox, 59, of Honey Brook, Pa., is a pilot, a mechanic, a teacher of fly-fishing, a sporting-goods dealer, an inventor, a cross-country skier and a trapshooter, to mention not all of the endeavors he zealously pursues. A few years ago he installed an English-type grouse walk on his 240-acre farm on the eastern edge of the Pennsylvania Dutch country and for awhile he and his neighbors took part in some of the most unusual shooting anywhere this side of the Atlantic. Now Cox has unveiled his latest brainchild, a space-age creation that seems to fall midway between Rube Goldberg and Star Trek. He calls this complex collection of lights, gauges and dials, the Magnificent Green Tennis Machine.

The product of a number of years of thought, three years of effort—in association with electronic engineers from Sperry-Univac and MIT—and more than $35,000, the machine is at least partially green, it does indeed involve tennis and it may actually prove to be of some value, if not exactly magnificent, to tennis players seeking to improve their games. What Cox' machine does—or, at least, what Cox says it does—is scientifically match a specific player to a specific racket, a mating that until now has been achieved only through trial and error.

Differences among racket frames involve considerably more than the obvious ones of cost, workmanship and cosmetics. Flex, stiffness, softness, grip size, weight and composition are only a few of the factors that come into play. The Dunlop Maxply Fort racket, for example, which has been around for years but which Cox considers to be the most complex ever built, is made of 25 separate pieces of laminated woods, including ash, beech, hickory, maple, mahogany and obeche.

Cox, who has been evaluating, testing, playing with and selling rackets for most of his life, is well aware of the problems that the tennis tyro faces. "The beginner walks into a store and sees a wall full of rackets," says Cox. "I asked a department store clerk recently what kind of racket he thought I should buy. He said, 'Buddy, I don't know anything about rackets. When you find one you like, I'll ring it up for you.' That's what a lot of beginners run up against. Utter confusion. The purpose of my machine is to end that confusion. We start by eliminating 90% of those rackets."

Cox does this by first making a psychological and visual evaluation of the player, beginning with a series of nine questions—e.g., "Do you know the exact name and model of the tennis racket you now own?"—drawn up by a psychologist friend, Dr. David Reed. According to Cox, the answers, combined with a visual appraisal of such obvious physical characteristics as age, weight, height and appearance, present a comprehensive picture of one's psychological and physical makeup. Cox then compares this picture with a numbered chart that evaluates the physical characteristics of some 80 rackets, until he comes up with the best five person-racket combinations.

Enter the Magnificent Green Tennis Machine for the final stage of racket selection. The player hits five balls, dropped at identical speeds from an overhead arm, with each of the finalist rackets. The speed of the racket head as it strikes the ball and the speed of the ball after it is hit are measured electronically. From these measurements, an efficiency factor (EF) is computed. To eliminate the possibility of mis-hits giving a false EF, only solid hits are computed. The racket that produces the optimum EF is, Cox contends, the right one.

This formula sounds almost too simple, but Cox says it works. So far he has programmed more than 1,000 tennis players at all levels of skill and he says that when they switched to rackets selected by the machine, they showed marked improvement. Beginners are more difficult to match with rackets, of course, but Cox is convinced that his invention also benefits their games if only by giving the psychological lift of knowing that from the start they are playing with the best racket for them.

Says Cox, "In the sense that all of us want the very best and not just something good, the machine is the scientific corroboration of the best."

The Magnificent Green Tennis Machine is currently ensconced in Cox' Bryn Mawr, Pa. sporting-goods shop where he is using it to build a data bank on person-racket combinations. Ultimately he would like to interest a large sports equipment manufacturer in using his machine to design rackets for specific types of players.

"This machine would take racket selection out of the hands of the tennis pros," Cox says, "and free them to teach. It would eliminate the need for resident pros in shops and department stores. And it would certainly sell rackets. Ninety percent of those who have been tested on the machine have bought a new racket."