Adidas’ New ‘Illegally Fast’ Shoes Make Running Feel Practically Effortless

Photo: W+G Creative/Adidas
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Eight years ago this October, I ran a half marathon. I’d dabbled in 5K mud runs over the years and gone on an occasional jog, but the runner badge was one that never seemed to stick for me. Then, when I moved to New York City for my first full-time career role working at a fitness magazine, I figured there was no better time to try to embrace the word—especially since the Rock’n’Roll Half Marathon in Brooklyn was just over six months away, giving me plenty of time to prepare for race day.

Fast forward through weeks and months of training and I completed the run without walking—my only goal for the race. It was challenging to say the least. So much so, that in the eight years since, I’ve once again been at odds with running.

Now though, the DC Rock’n’Roll Half Marathon is just six months away and I’m once again feeling pulled in that direction. The big difference? I have the Adidas Adizero Prime X 2 Strung Running Shoes ($300) to my advantage, a pair of shoes that technically qualify as “illegally fast.”

Adidas Adizero Prime X 2 Strung Running Shoes — $300.00

Sizes: Women’s 5 to 16; men’s 4 to 15
Colors: 2
Drop: 6mm
Weight: 10 oz. (size 9)
Stack height: 50mm


  • Extra high stack (50 mm) for optimal cushioning
  • Inclusive sizing
  • Forward-momentum design


  • Heavy under the feet
  • Only sold in two colors
  • Expensive

The buzz behind the Adizero Prime X 2 Strung Running Shoe

These new fast running shoes from Adidas are so high tech that elite athletes aren't allowed to race in them—although they’re perfectly acceptable for the rest of us who are simply aiming to beat our own personal records, rather than, you know, world records. Since the vast majority of runners are non-elites, Adidas decided to design a shoe without the constraints of race regulations and see what would happen.

The result: The Adizero Prime X2 Strung running shoe boasts a massive stack height and double carbon plate. Designed with three layers of Lightstrike Pro foam, the stack is a whopping 50mm. Currently, World Athletics Footwear Regulations require that stacks not surpass 40mm for elite road races. The reason stack even matters is because the higher the stack, the more shock absorption a shoe has, and ultimately the faster a runner can move. Additionally, the World Athletics Footwear Regulations says competition-ready shoes can only feature a single carbon plate, while the new Adizero Prime X2 Strung Running Shoe features two. By having double the carbon, these shoes are incredibly responsive and provide more bounce beneath your feet without requiring extra energy, making you better able to spring into action and maintain that momentum.

Photo: Author

Beyond the banned characteristics, the Prime X 2 Strung showcase a truly unique upper. Despite looking like it’s held together by threads, the upper is expertly-crafted with supportive layering that allows it to conform to your foot, much like a sock. It’s incredibly lightweight, not to mention breathable, both of which play a significant role in mid-run comfort.

What the shoes feel like to run in IRL

After testing Adidas Adizero Prime X 2 Strung Running Shoes out for the past two weeks, I can confidently say that these running shoes are unlike anything I’ve ever stepped foot in—and I’ve tried many, many sneakers.

Let’s start with looks. The Prime X 2 Strung feature a chunky-yet-streamlined silhouette that looks on par with 2023 fitness fashion trends while also nodding a bit to the future. The threaded uppers are a sight to behold—they simultaneously look like a glitch and like something Spiderman hand crafted with his webs. All in all, I dig the appearance. I do, however, wish that they were sold in more colors. (I still drool over the OG Adizero Prime X Strung Pulse Mint/Lucid Fuchsia pair.)

Appearance aside, the performance of the Adizero Prime X 2 Strung Running Shoes honestly feels almost too good to be true. Of course, I’m no sprinter or elite athlete. When I’m really booking it, I can run a mile in a little less than nine minutes. I’m also mid-sized (a size 12/14), so I often find that running can trigger shin splints, which is said to be more common among larger people. With that in mind, I find the Adizero Prime X 2 Strung Running Shoes to be a total dream. Truly, I have never run more effortlessly. It’s as if the double carbon-infused plate, high-foam stack, and 6mm drop cushions my every landing while simultaneously propelling me forward.

Photo: Author

Additionally, the minimal drop makes forefoot running feel natural. And since the stack is so high, I can hardly feel my footstrike, so my shins haven’t felt triggered at all. Instead, the double-carbon plate acts almost like a trampoline pushing me to the next step, which is ideal for someone looking to regrasp that runner badge.

All in all, I find that the Adizero Prime X 2 Strung Running Shoe offers a bouncy ride that feels supportive, not wobbly. They’re not without downsides, though. Walking in them can feel a bit unnatural due to the weight, height, and cushion. While I wouldn’t go as far as to say I feel at risk for a twisted ankle, I will admit that they feel less stable while walking than running.

Speaking of weight, the Prime X 2 Strung are two ounces heavier than the original version of this shoe. Because of this, you may feel weighed down mid-stride, especially if you’re sprinting and/or running long distance. (Interestingly enough, Adidas just announced its latest jaw-dropping new model, the Adizero Adios Pro Evo 1, weighs just 138 grams, or 4.8 ounces—shockingly light!—with limited pairs available to non-elites for $500.)

Personally, for a few miles here and there at a moderate pace, I find the Prime X 2 Strung to be a stellar pick, albeit an expensive one. Now, to see if they inspire me to book my second half. Only time will tell!

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