Auxetic - The Science Behind the Sensational Feel

The inside story of how two British scientists collaborated with HEAD on the innovative Auxetic construction, which will give you sensational feel with every shot.

What connects HEAD tennis racquets with nuclear reactors that have been built to withstand earthquakes, as well as to the cutting edge of aerospace and biomedicine? 

The answer - and this promises to give you sensational feel with every shot you play, supercharging your confidence - is Auxetic materials. Named after the Greek word 'auxetos', which means 'that which grows', Auxetic materials do something very surprising when stretched along their length: they become fatter. They have another counterintuitive property - when compressed, they get thinner. 

This is the first time that a tennis manufacturer has used Auxetic construction to make a racquet. And, according to the two British scientists who have collaborated on the project with HEAD, it's a technological breakthrough in tennis racquet engineering that could potentially transform the sport and perhaps even the entire sports industry. "This is a hugely exciting project," says Professor Andrew Alderson from Sheffield Hallam University. Alderson, who has been researching Auxetic materials for the best part of 30 years, collaborated on the project with Dr Thomas Allen from Manchester Metropolitan University, a global expert on tennis racquet technology. 

Alderson feels "a huge amount of pride" to have worked with HEAD on this project: "This is big." "Auxetic materials have properties that conventional materials don't," Alderson says. "That includes enhancing vibration dampening and energy absorption, and after Tom told HEAD what I was working on they said they wanted to have a look at how they could use Auxetic materials in their racquets." 

Tennis players of all levels - from beginners to the elite athletes on the ATP and WTA Tours - will have more confidence in their games thanks to the Auxetic construction in the carbon fiber yoke piece of their HEAD racquets. When you hit the ball, the yoke piece actively responds in real time. It adapts its internal structure, deforming to give you optimal impact feel and highly accurate feedback. Research has shown how the Auxetic construction will improve your feel on every ball you play, even when you hit the ball off-center, outside the sweetspot. 

"The first thing we did was assess HEAD's materials to check that they could make them in an Auxetic way. Based on that we did some design calculations and HEAD made some prototypes," discloses Alderson.

HEAD's on-site factory meant it was faster and easier to make prototypes, speeding up the development process. The feedback from players was extremely positive. "HEAD did trials with players and my understanding is that the Auxetic construction increases players' confidence in their shots as you get an enhanced feel for the ball, including when it is off-center," says Alderson. "If it's slightly off-center it stretches some strings more than others, and you're getting a reaction where you need it, so you're getting more feeling and control. That's feeding back to the player who can feel the shot better, and that gives them more confidence in the execution of their shot." 

Auxetic construction will probably lead to players hitting the ball with more pace and spin. "If you're hitting the ball more confidently that allows you to hit it harder and apply more spin. The speed of the game is always increasing. Tennis racquets are always improving in some way. What we can't say yet is whether Auxetic could bring about a step change in the sport, but that's a possibility," says Allen. "If racquets have better feel and are easier to use, that's going to encourage more people to play. And when you have a larger population of players, that could result in improvements at elite level." 

Tennis isn't the only sport in which you can experience the sensational feel of Auxetic construction - it's also being used for HEAD padel racquets. Whether you're on a tennis or a padel court, the new Auxetic construction will boost your confidence.

The scientists hope that this is just the start of the Auxetic story for HEAD. "Now HEAD could really explore what they can do with Auxetic materials. Auxetic opens up so many possibilities about how you can make racquets. In five, ten and 20 years. I hope that HEAD will be using Auxetic materials in ways that we can't even think of right now,” Allen says.

“It could be that, because of Auxetic materials, HEAD will end up making tennis racquets completely differently in the future, including with new shapes. It could make it easier to have smart racquets with sensors in them, and there could be sustainability benefits. In years to come, we might find ourselves looking back and saying, 'That was the first tennis racquet with Auxetic composites, that was the racquet that changed the sport'. That would be massive."