I recently sat down with John Lyons, Wilson’s Global Product Director for racquets and strings, to discuss the company’s newest technology—SpinEffect, which aims to increase recreational players’ spin production with a novel, 16 mains by 15 crosses string pattern. (The two racquets engineered with SpinEffect, the Wilson Steam 99S [pictured] and the 105S, will debut in January 2013.) In part one of our interview, we spoke about recent technological advances in tennis, equipment shifts on tour, and how Wilson has sought to figure out spin.

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Justin diFeliciantonio: In the past 30 odd years, tennis equipment has advanced by leaps and bounds. What do you see as game-changing moments, particularly in racquet technology? In the past 30 odd years, tennis equipment has advanced by leaps and bounds. What do you see as game-changing moments, particularly in racquet technology?

John Lyons: There have really been five big transitions in racquet technology. The first big one was wood to metal, the change in materials. From there, we went from metal to oversized racquets like the Prince Graphite; next, oversized to graphite. Then we made widebody frames, for example the Wilson Profile. Finally we took weight out of the handle and created more head-heavy frames. That was the Wilson Hammer.

All the changes have been about one of two things: More power or a bigger sweet spot. Wood to metal increased the power. Metal to oversized increased the sweet spot. Graphite and widebodies also increased the power. And the Hammers, they hit with more power as well as a bigger sweet spot.

JD: I understand that newer materials and wider constructions made racquets more powerful, and that bigger frames increased the sweet spot. But how does changing the balance amplify the sweet spot?

JL: With the Hammer, remember, we made the racquet lighter and increased the mass in the racquet’s head. When you move the balance point like this, the sweet spot not only shifts up, but it also expands. On a traditionally-weighted racquet, because there’s more mass in its handle, the sweet spot is actually below the center. That’s just the physics of it.

JD: That being the case, it’s interesting that so many professionals still play with fairly head-light racquets, given that so many of them hit the ball near the top of the stringbed. Why is this the case?

JL: I think it’s two things. One, they’re not so concerned about getting power from their racquet. They’re generating more of their own power with their swings. But on the other hand, I think it is changing. Lighter, more evenly-balanced racquets are becoming more prevalent on tour. Take the Babolat Pure Drive or the Wilson Juice, for example, which are pretty light, evenly-balanced racquets. As the younger players come up, I think this shift will continue. Still, there a number of experienced pros who hit near the tip of the racquet with head-light frames; they like the feedback and feel they get out of that. They know when they’re not hitting on-center.

JD: Beyond the move toward lighter, more evenly-balanced racquets, what would you say has been the last major technological shift on tour? Monofilament strings?

JL: Absolutely. In the past eight, nine years, Luxilon and other polyester strings that amplify spin production have really swept through the ranks of high-level players. You know, it’s interesting, years ago tennis physicists and a number of us in the industry had doubts that monofilaments actually gave pro players more spin. We thought it was in their head—that the string, being deader, forced them to swing harder, which caused the increase in spin.

JD: That was the argument put forward by Rod Cross and Crawford Lindsey in Technical Tennis, when it first came out in the early 2000s, right?

JL: Yeah. But now, we actually do know that the string generates more spin. And it’s a result of polyester’s “snap-back” effect. When we [at Wilson] first started working with Luxilon, I remember hearing people say to the guys at Luxilon, “Hey, it’s great that your strings don’t move. I don’t have to straighten them back out after every point.” And the Luxilon guys would laugh and say, “Well, it does move. But it moves so quickly back into position that you don’t see it move.”

This snap-back effect, and the added string it produces, it’s really affected the pro game. So 10 or 20 years ago, if you needed more control on the court, you’d shorten up your swing or slow it down. But with today’s game, players hardly ever let up on their swings. Because, by swinging hard, they can use the spin to keep the ball in the court. This is the evolution of the game, and it’s why there aren’t as many players who hit flat or come into the net anymore.

JD: So you’re saying that, today, with the new strings, power and control aren’t mutually exclusive. They work together.

JL: Exactly. With more spin, you can still hit hard and place the ball where you want in the court. With more topspin, your margin of error is also higher. That’s how the game’s evolved.

JD: You told me back this spring that Wilson was attempting to study the snap-back effect, though at the time you were a bit vague on the details. What has the company discovered?

JL: A lot. So for quite some time, what we’ve tried to do at Wilson is, number one, understand how spin’s generated, and number two, design new technologies that could enhance that effect. The idea, obviously, was trying to create a racquet that would impart more spin on the ball.

So in trying to understand spin, we started by looking at high-speed video, particularly the 4/ or 5/1000ths of a second during which the racquet makes contact with the ball. To do this, we did what everyone in the industry does initially, which is to fire balls at an angle off of the stringbed. The ball is marked, and we’re able to measure the number of rotations per minute, as well as the speed in and speed out. And basically, what we found is that spin is due to three things: The angle of your swings, your racquet-head speed, and the snap-back effect. If you swing absolutely flat, or swing very slowly, the snap-back effect becomes moot. But while we can’t change your swing plane, or make you swing faster, we can make a racquet-head that will amplify the snap-back.

We also started using a technology called TrackMan, which has actually been used in golf for a while. It uses Doppler radar to track objects’ movements through space. You know watching golf on TV, when the camera will show where the ball went, how it curved, its trajectory? TrackMan can do that. So we programmed this technology for tennis, and set it up behind the court. This allowed us to test variations in a real-world setting. So we’ll have the ball machine firing balls, and say you hit 15 forehands and 15 backhands, and just try to hit the same way. 15 with Racquet A. 15 with Racquet B. With each hit, the technology can measure the balls’ rotations per minute. My hits are 1200, 1300 RPMs, which are not very high. We’ve tested some players who have hit in the 3000s. So what we can do, then, if you hit 30 or however many balls, we can get an average. It’ll tell us the speed of your ball, its clearance over the net, the arc of the ball, the angle down and the angle up, and if we give you a cone to hit, it’ll map the spots and create a plot that shows us how close you got to hitting it. All this data opens up a lot of possibilities.

JD: This sounds pretty fascinating.

JL: It is. With this technology, we were able to experiment in many different ways, particularly with string patterns. We tried patterns with all the crosses and fewer mains. All the mains with fewer crosses. We tried symmetrically opening up the pattern—so 16 by 14, 14 by 12, 12 by 10. And what we found out was that the secret to increasing spin was not opening the pattern up symmetrically. The secret was to reduce the cross strings, which frees the main strings to move and snap-back more. And that’s because, when the number of cross strings are reduced, there’s less friction. If you think about it, it’s a pretty obvious solution to trying to enhance the strings’ snap-back and create more spin. After all, as the racquet’s parallel with the ground as you’re hitting up, it’s the main strings that are moving when you try to hit with spin.

JD: What pattern did you end up with?

JL: 16 mains by 15 crosses. We call it SpinEffect technology.