“What is this?” Jason Day said.

On his face was the huge, genuine smile that golf fans became used to seeing at the end of the 2015 PGA Tour season. And on this Tuesday after the Tour Championship, how could he be anything but smiles?

Jason Day, holding the original Tour360, with Sergio Garcia.

In his last five tournaments, Day had won his first major championship, two FedEx Cup Playoffs events and became the No. 1-ranked golfer in the world. He was technically working, but standing next to Sergio Garcia and Dustin Johnson, the moment felt more like a Tuesday practice round with friends than an Adidas photo shoot.

The topic of conversation among the top-ranked golfers was the items in front of them, Adidas’ Tour360 golf shoes. Day was holding the original Tour360, now a decade old, and couldn’t help but laugh.

“They look like bowling shoes,” he said. “And how heavy they are.”

Off camera but within earshot was Masun Denison, who was on the team that developed on the original Tour360’s. Now the director of Adidas’ Golf footwear, he couldn’t help but interject. Denison was far from offended, but he made sure to say — loud enough so that Day could here — that the shoes were “revolutionary in their day.”

He had a point.

Ten years ago, athletic-styled golf shoes were an oddity. Now they’re the norm, at least partly thanks to the Tour360.

The latest version of the Tour360, officially called the Tour360 Boost, has similarities to the original model, but many more differences. One of the biggest changes is the addition of the namesake “Boost” technology.

Adidas’ Tour360 Boost golf shoes use Boost in both the heel and forefoot of the shoe.

Boost solves an important design dilemma — one that most golfers likely don’t even know exists in their footwear. Shoe designers have always had to choose between making a shoe more comfortable by using softer materials and making it more responsive by using firmer materials – which of course, reduce comfort.

Boost is a special, lightweight foam material made up of thousands of pressurized pellets that compress to provide softness, but then “rebound” toward a golfer’s foot to improve responsiveness.

The “holes” on the outsole of the shoe allow the Boost material room to expand when the foot presses down, and then “rebound” back toward a golfer’s foot.

Last year, Day, Garcia and Johnson transitioned into Adidas’ Boost technology with the company’s AdiPower Boost golf shoe, which integrated the material into the heel. With the Tour360 Boost, the material is used both in the heel and forefoot of the shoe.

As the cameras started rolling, Garcia and Day were still chatting with Denison about the original Tour360, but Johnson’s attention was focused on another shoe.

“I loved these,” he said, looking at the black-and-white Tour360 LTD.

Unlike the most-recent Tour360 models, the Tour360 LTD’s were made of a premium, full-grain leather, and they received unanimous praise from the three golfers for their looks.

Adidas Tour360 LTD

“I think it was the first really sharp, sporty-looking shoe we had,” Garcia said.

The Tour360 LTD also had a special place in each of the golfer’s memories. Johnson won his first PGA Tour event – the 2008 Turning Stone Resort Championship – while wearing them. Jason Day remembered wearing them to make a hole-in-one at the same event. Garcia wore them to win The Players Championship in 2008.

The Tour360 Boost shoes are waterproof, and are constructed with premium, full-grain leather.

With the Tour360 Boost, Denison and his team chose to return to the leather construction to pay tribute to the history of the iconic golf shoe. Another homage, however, maintaining the Tour360’s standout feature, is significant to the design because it adds better performance.

The original Tour360’s were given their name because of their “360Wrap,” an independent saddle that cradles the mid-portion of the foot. It adds stability, but improves fit, too. Since it’s connected to the lacing system, the 360Wrap adapts to the shape of a golfer’s foot, moving outward to accommodate golfers with wider feet, or inward for golfers with narrower feet. The 360Wrap works the same way in the Tour360 Boost, but there are two key differences.

The Tour360’s “Torsion Tunnel.”

For one, Adidas designers built what looks like a bridge (Adidas calls it a Torsion Tunnel) underneath the 360Wrap. Previous Tour360 models had a split sole, or a gap between the heel and forefoot.

In the past two-to-four years, Denison said Adidas has learned an incredible amount about traction through studies that not only measure a golf shoe’s dynamic movements, but the movement of a golfer’s feet inside golf shoes. One of the biggest takeaways from those studies was that a split sole was not optimal for maximum traction.

Dustin Johnson, Sergio Garcia and Jason Day look through the Torsion Tunnel.

“To get the most grip possible, we couldn’t have a gap in the middle,” Denison said. “We knew that if we connected the heel and forefoot, we would get addition performance.”

The mission was on to keep the 360Wrap, but find a way to maximize traction. The result was the bridge, which adds rigidity that improves the stability of the shoe, but still allows the heel and forefoot to move independently. And true to its original intent, the bridge’s “nubs” create better traction, between 10-12 percent according to an Adidas study.

The “bridge” of the Tour360 includes traction elements to improve friction.

The other new feature of the 360Wrap is specific to the “Boa” model of the shoe. The Tour360 Boost is offered in two models – one with laces ($200) and one with a lace-less Boa system ($230), which uses cables that tighten and loosen the shoe through an adjustable dial.

The Boa cables actually weave through the 360Wrap in the new shoes, technology that Adidas co-engineered with Boa, and use a special dial positioned on the shoe tongue. The dial can make micro adjustments, offering 1 millimeter of tension adjustment per click, which allows golfers to lock in in the perfect fit.

Adidas Tour360 Boost with Boa.

Day had just finished changing his outfit for a television commercial when I caught up with him to talk about the new shoes. As he came out of the golf-cart-turned-dressing-room to put on a pair of Tour360 Boost shoes, which happened to have laces, he told me how much he liked Adidas’ new Boa system.

“I don’t have to tie my shoes anymore,” Day said. “I’m pretty finicky about footwear and how tight it should be.”

An initial sketch of the Boa technology used on the Tour360, which is integrated into the 360Wrap.

Last year, Day started wearing the AdiPower Boost shoes with Boa regularly, including during his PGA Championship win. He revealed that he had worn roughly 20 different pairs of shoes – 10 black and 10 white — throughout the year “to keep things looking fresh,” changing shoes the most during his winning spree.

“I was pretty much a nobody before this year,” Day said in a moment of humility.

Garcia and Johnson disagreed. Few golfers are better statesman for the game than Day, who told me he signs the shoes that he no longer plans to wear and gives them away to fans.

Testing Thread: Enter to be part of the official GolfWRX Tour360 Boost Testing Panel

As the photo shoot came to a close, Garcia was asked what he thought of the older Tour360 shoe models. He was the most complimentary of the three golfers, maybe because he remembered what it was like to play a professional golf schedule in shoes that were far less advanced than even the 10-year-old Tour360’s.

“I won [PGA Tour] tournaments before the Tour360’s came out,” Garcia reminded them.

At the time of Garcia’s first PGA Tour win, the 2001 MasterCard Colonial, Day was 13 years old. Johnson was 16.

The Tour360 Boost use an S-curve heel, designed to mimic the shape of an achilles tendon to improve comfort.

With all that goes into modern golf footwear, it seemed fair to ask Garcia if shoe technology had changed the way he played. Did he swing harder, or hit different shots?

He thought about it for a few moments before he responded.

“No,” Garcia said. “I’ve always tried to play as aggressively as I can.”

I pictured the famous shot he hit, eyes closed, with his ball dangerously close to the base of a tree at the 1999 PGA Championship at Medinah. Sergio has always been Sergio. No shoe would change that. What Garcia said next summed up what Adidas is really celebrating with the Tour360 Boost and its 10-year celebration of the golf shoe line.

“I’ve been lucky to be with Adidas for 16, 17 years now.” Garcia said. “I’ve never felt like I was at a disadvantage.”

History says golfers will feel the same way about Adidas’ golf shoes 10 years from now.

To learn more about the Tour360 Boost and its availability, visit Adidas’ website.