Adidas Reviews


The Adidas Ultraboost 21 is the cushiest and most responsive version yet, serving up a springy ride that returns considerable energy in every stride.


From its inception in 2015, the Adidas Ultraboost has been a maximally cushioned training shoe built on a thick, lively platform of extremely resilient Boost midsole cushioning. The Adidas Ultraboost 21 is the cushiest and most responsive version yet, serving up a springy ride that returns considerable energy in every stride.

Adidas Ultraboost 21 Review


The Ultraboost 21 has 6 percent more Boost foam in the midsole. It features an updated torsion system and rocker geometry that enhances forefoot stiffness by 15% for an even more responsive run.

In addition, the upper has been enhanced with a tighter and stiffer knit pattern to improve its fit and feel. The new, slightly wider overall footprint improves its stability and balance.

The compressive knit upper is made from a mesh material called PrimeKnit+, which contains 75 percent Primeblue yarns. It’s essentially a stretchy, full-bootie construction bolstered by a soft plastic exoskeleton cage. The cage wraps the saddle and an elf-like flare off the back of the heel to ease tension on the Achilles tendon.

Adidas has shown a huge commitment to sustainability with its marquee shoes. About 50 percent of the materials in the Ultraboost 21 are made from Primeblue yarn. This is a high-performance recycled material made from Parley Ocean Plastic recovered from the sea. Just as important, no virgin polyester was used in this shoe.


The Ultraboost 21 fits true to size with a medium-volume interior. It has a slightly more spacious heel and forefoot. This creates a locked-down feeling through the midfoot thanks to a soft plastic exoskeleton cage. This cage engages the Adidas “three stripes” logo and the lacing system. The step-in feeling is luxurious, both from the plus interior padding, the premium footbed and the soft maximally cushioned midsole that feels like a bed of bouncy rubber marshmallows. 

That sensation is accentuated when you’re running. The thick cushioning in the heel reduces ground impact shock and starts the process of rolling the foot forward. Once the new torsion system under the arch is engaged, it creates a gentle but distinct rolling sensation of being propelled forward toward toe-off. Ultimately, the Ultraboost 21 is a slightly heavier, well-cushioned trainer with a comfortable upper, responsive midsole and vivacious ride.

Adidas Ultraboost 21 Review


The Ultraboost 21 is a soft, lively everyday trainer that provides long-haul comfort and consistent flow in every mile. It doesn’t have the pep for faster workouts or races, but it’s ideal choice for long runs, recovery runs and moderately fast tempo runs.

Runners who appreciate maximally cushioned neutral shoes with enormous energy return will really love the Ultraboost 21. Taller and bigger runners will appreciate the proficient shock-absorption in every stride. Smaller runners or runners who like to “feel” the ground might find the midsole to be excessively thick.

Adidas Ultraboost 21 Review


Our wear-testing runs determined that the Ultraboost 21 seems to help improve the recovery process after a long run. Normally it takes several days to recover from a two-hour training run. However, our wear-testers reported having fresh legs just a day or two after logging a moderately paced 15-miler.

There is a new Linear Energy Push torsion system embedded in the bottom of the midsole. This is essentially a curvy hard plastic plate with a two-pronged design that stretches from the midfoot to the forefoot. This system adds notable stiffness that works in conjunction with the shoe’s rocker geometry and Boost foam to promote forward prolusion.

The outsole feature three types of rubber with soft, medium and hard densities that combine to provide optimal traction, durability and flex.

Interestingly, Ultraboost shoes have always had amazing street cred. This is thanks to celebs like Kanye West, Carrie Underwood, Kylie Jenner, Jessica Alba, Meghan Markle and Sarah Michelle Gellar wearing these kicks casually or with athleisure apparel. And let’s face it, there’s no other running shoes that look good with a pair of jeans and a T-shirt.

Adidas Ultraboost 21 Review


The biggest drawback of the Ultraboost 21 from a running point of view is the weight. No matter how you slice it, 11.9 ounces (for a men’s size 9.0), is a pretty heavy load to carry through every stride, even with the amazing energy return.

For slower to medium-paced runs, it serves up a flowy ride but it’s a challenge to run faster speeds for very long.


Adidas Ultraboost 21 Tech Specs


Men's Adidas Ultraboost 21
Women's Adidas Ultraboost 21 Review