This is the third generation of Spieth's namesake shoe, and it was created with a focus on the biomechanics of the swing with the help of J.J. Rivet of the European Tour Performance Institute. Under Armour focused on Rivet's findings on torque and rotation during the golf swing, and what that means for stabilizing the foot. Those findings resulted in a design that keeps the shoe in contact with the ground as long as possible. Of course, the longer the foot is in contact with the ground, the more opportunity the golfer has to use the ground as leverage to create power in the swing, a big trend in golf. Another benefit to added stability is balance.
There are a few different technologies that help achieve this. Most visually obvious are the cleats, some of which are asymmetrical. The combination of the low-profile UA Rotational Resistance (RST 2.0) and the Softspike™ Silver Tornado provide stability and the ability to help a golfer rotate. If you look closely at the outsole, you'll also notice the carbon-fiber plate for lateral stability. The outsole itself sits low to the ground, increasing interaction with the ground.
To make the shoe lighter, the upper is made of leather and textile—instead of just leather. The upper is both waterproof and breathable.
Spieth penned an essay for Under Armour, in which he talks about how he is involved in the development of his namesake shoe, how the collaboration works, and what he's looking for in a golf shoe.
"The collaboration has worked well and allows us to get creative," Spieth writes. "For example, the seed for the Spieth 3 was actually planted while finalizing the Spieth 2, although I didn’t realized it at the time. Forsey and his team had come to my house to show the final Spieth 2 prototype. We were sitting at my kitchen table when I got an idea that would help me explain my thought process. I ran to my closet and grabbed the UA trainers that I always wear to the gym. I remember saying to them, “This is how I want the Spieth shoe to feel, like I don’t have anything on my feet.”
"UA didn’t disappoint, and really took my request as a challenge. The next time I saw the Spieth 2 it had a custom woven fabric for the quarter. Fast forward to the Spieth 3, they took that fabric all the way up to the vamp and around the heel, taking out weight without losing stability, all while giving me that sneaker feeling."