As tennis speeds up on the court, including at the 2020 Australian Open, which began this week, racket evolution hustles along off the court, with technology to create more power and spin within the game. Companies across the globe, from Japan to Austria and Chicago to France, all take their own high-tech view on the process.
Think: sheets and rolls of carbon fiber in climate-controlled rooms, new iterations of graphite, and a completely updated computational design that offers a fresh perspective on flex and stiffness of frames. All advancements define modern tennis racket manufacturing.
Take the January 18 release of the new Yonex EZONE, an update of a popular frame played by the likes of Naomi Osaka and Nick Kyrgios. The completely updated design—both in a 98- and 100-square-inch head—creates a larger sweet spot by widening the isometric head and then further ups the power game by introducing a new M40X graphite, never before used in sporting goods, but with more strength and elasticity to help with the balance of stability and flex.
“The properties of this graphite are that at faster swings, it stiffens,” says Nicole Laduca, a spokesperson for Yonex. “The graphite provides stability and flex.”
The new graphite pairs with the unique way Yonex designs and manufacturers tennis rackets. The Japanese-based company is the only with an isometric head, meant to improve the sweet spot location by 7 percent compared to a conventional round shape by optimizing the intersection of the main and cross strings. By flatting the top, more main string gets lengthened, also improving control. By widening the EZONE at the 3- and 9- o’clock areas of the racket, Yonex has made the sweet spot even larger, aiming for a more “comfortable feel.”
To help, Yonex has varied the angles of the frame’s beams, making them softer or firmer, depending on the needs, and then creating a racket throat with more stability for a softer feel in the head. The new graphite in the throat makes it all possible. A fresh vibration-dampening stretchy mesh wraps the grip to improve comfort.
Known for its precise manufacturing style, Yonex makes its rackets out of its Japanese factory and prides itself on all frames falling within exact specifications by going through a 50-point check. This process includes precise grommet hole drilling technology that can drill straight holes at the 5- and 7 o’clock areas—the only company to achieve this, Laduca says. With image scanning used to examine the quality of each drilled hole, the precise angles of the holes give the strings specific performance qualities.
This week, Osaka, who tested out the new racket over the tennis offseason, will debut the model during the Australian Open.
Osaka’s new frame won’t be the only high-tech design on the Australian courts. From the labs of Wilson in Chicago come repeated updates to some of the most popular models in the game. The brand revealed an entirely new approach to racket manufacturing in 2019 with the Clash, all while giving the Blade franchise —known as Serena Williams’ racket of choice—a complete makeover.
Wilson Labs, a 40,000-square-foot facility near Chicago’s O’Hare International Airport, houses all the engineering, prototyping, and testing of new racket designs.
The Clash debuted in 2019 after years of research and testing that aimed to build a racket from the ground up. What started as more than 600 original ideas dropped to 206 feasible concepts. As the design team put a focus on improving the number of milliseconds a ball stayed on the racket to help with player control, six ideas eventually went into concurrent prototyping, putting the lab in full engineering.
CAD systems and finite element analysis gave the team a place to start and 3D printing inside the lab gave real shape to the concepts. The final Clash iteration offered a fresh perspective on carbon fiber design, with the frame construction including nonconventional angles to offer new dimensions of the frame beam. By using the digital mapping, the engineering team built stability into a racket that bends and flexes—because of the new approach to carbon fiber layups—in an entirely new way.
“We can make a prototype and test it as fast as possible,” says Bob Kapheim, Wilson’s innovation manager, about the climate-controlled, carbon-fiber filled room within the lab. “That is really enjoyable as an engineer. We get to work with advanced materials from the aerospace industry, but if something goes wrong, nobody dies.”
Even with the Clash an early success, Wilson didn’t want to lose traction on its well-known franchises, whether the Roger Federer-played Pro Staff, Blade, or others. The 2019 Blade version 7 update includes 20 percent more horizontal flexibility to improve control, 12 percent more vertical flexibility for additional spin and 11 percent more stability for power. Using the new carbon fiber mapping insight found in the lab during Clash engineering, the updated Blade frame allows for a new combination of stability and flexibility at different points along the swing path.
Babolat, a French-based company that stands as one of the most popular racket makers on the pro game with its Pure Drive line and Rafael Nadal-played Pure Aero line, went back to its lab in 2019 to create an update to the Pure Strike line, used by Dominic Thiem. The Pure Strike 2019 features a new beam design, which Babolat says combines the stability of a square beam frame with the dynamism of a regular elliptic structure, all centered around control.
By adding in a new vibration filtering technology through the frame, Alex Israel, category manager globally for Babolat, says the sharp control offers a “mix between modern control and that pure feel that makes a huge difference on the court.”
Dunlop introduced a brand-new material to tennis racket manufacturing in 2019 and expanded it in 2020. And you may have seen it before, underfoot. Partnering with BASF to use Infinergy, known as Boost when Adidas uses it on footwear, the super-elastic rebound expanded thermoplastic polyurethane comes lightweight and outperforms standard foam. In a racket, Dunlop tennis researchers in Japan found that placing the refined Infinergy in the 2- and 10 o’clock areas of the frame, applied in a thin layer, coupled with updated frame geometry, reduces vibrations and impact shock, helping create a 30 percent larger sweet spot while increasing damping 37 percent.
Originally debuted in the CX line, the newly released SX line features the material, expanding Dunlop’s use of the technology for tennis. The new SX design also includes grommets that allow strings to move in specific directions to allow more spin on the ball. This new manufacturing style uses a fresh approach to grommet construction to allow the more slide on the strings to “bite” the ball, improving spin and control on off-center strikes.
“Spin Boost technology is a completely new concept when it comes to enhancing spin,” says Kai Nitsche, vice president and general manager of Dunlop. “The extra spin it produces is helpful, but just as importantly, Spin Boost makes each shot more consistent and predictable for players.” Dunlop tested the design using a robotic swing machine to compare against competitors, testing spin rates on a variety of shots.
Volkl, a German-based racket maker, has put its manufacturing efforts squarely on reducing arm fatigue for players. Volkl has enhanced EVA foam in the racket handle by adding resin to make the foam denser, allowing for 25 percent more shock absorption. The brand’s VCell technology, in partnership with German research company Fraunhofer, brings what the brand calls “the highest grade of carbon fiber construction currently available” into rackets to make then more resilient while lowering frequencies. The March 2020 release of the VCell line will increase the use of the carbon fiber materials beyond what is currently been in use in the VFeel line since 2018.
And in Austria, Head is making more than just skis. Racket development starts with computer simulations in the Head labs. After an initial design and testing, rackets hit the courts for player feedback. For Gravity, Head’s latest release endorsed by Alexander Zverev, the company looked to improve the sweet spot of the frame by adding in a technology dubbed Graphene 360+. This creation improves energy transfer by using spiral fibers for more flex in the racket on ball impact.
As tennis fans watch the evolution of the on-court games, it all starts with engineers, technology, and materials derived in labs the world over.