adidas Ultraboost 21 Review 2021

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The adidas Ultraboost is one of the most renowned sneakers ever created. Since its launch in 2015, the Ultraboost has embodied the perfect convergence of function and fashion, earning it a cult-like following in both the running world and fashion circles alike. Of all the shoes I’ve tested (and I’ve tested a ton), the over-the-top comfort and style of the Ultraboost 21 is second to none. One of the best adidas running shoes and overall best adidas shoes of all time, the Ultraboost has universal application as a running, walking or everyday sneaker — making it a great holiday gift for just about anyone.

adidas’ ever-popular Boost midsole has long been the headliner for the Ultraboost franchise, and remains so. Developed in 2013, Boost was a revolutionary new foaming process that produced a midsole foam far superior to anything at that time. It provided the seemingly contradictory attributes of soft cushioning and high-energy return. The development of Boost altered the course of the entire shoe industry and found its way into nearly every adidas shoe thereafter.

The Ultraboost 21 is the best iteration of adidas’ flagship model I’ve tested. The most visible update comes in the way of a thicker midsole, which has 6% more Boost foam than that of previous iterations. Thanks to this, running in the Ultraboost 21 offers a similar sensation to jumping on a trampoline; the harder my foot hits the ground, the more upward pop the shoe gives back. Each bone-jarring ground force is muted and replaced with a soft, comfortable underfoot ride — something every runner will appreciate.

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Perhaps the most notable update to the shoe, however, is the discreet addition of a firmer underfoot feeling. If there was one flaw in the previous UltraBoost versions, it was that the forefoot felt structureless, causing it to lack a smooth, snappy toe-off. To fix this, the newly designed Linear Energy Push system, or LEP as adidas calls it, adds more firm plastic underneath the forefront. According to adidas, this additional support increased forefoot stiffness by 15%. And it shows too. I found the forefoot stiffness of the newly added LEP to counterbalance the soft Boost midsole much better than the previous torsion system, resulting in a snappier take-off at the toe.

adidas ultraboost design — The new torsion system provides a 15% increase in forefoot stiffness for a more responsive run.

CREDIT: Courtesy of Adidas

Out-of-the-box, the Ultraboost 21 fits and feels phenomenal. The stretchy nature and one-piece design of the soft Primeknit upper wraps the foot like a cozy pair of socks for a snug, but not too constricting, fit. Between the soft underfoot cushioning of Boost and the sock-like fit of the Primeknit upper, it’s no wonder these shoes are insanely comfortable.

Comfort aside, the Ultraboost 21 is an exquisite-looking shoe, earning it just as much of a reputation among fashion-minded sneakerheads as runners. Its sleek silhouette is offered in more styles and colorways than any other running shoe, including those designed in collaboration with partners like English fashion designer Stella McCartney and Finnish label Marimekko.

Bottom line is, I’ve been a shoe tester since 2014 and found that few other running shoes combine performance, comfort and style as well as the adidas Ultraboost 21 does. Select styles of the shoe are currently discounted as part of adidas’ Cyber Monday sale, but they’re going fast, so don’t hesitate to pick up a pair now on adidas.com.