What Makes the Adidas Ultraboost 21 Such a Popular Running Shoe?
The Adidas Ultraboost has become one of the most popular running shoes on the market, and the latest iteration – the Ultraboost 21 – looks to continue that legacy. With significant updates to the midsole, outsole, and upper, the Ultraboost 21 provides an unparalleled blend of comfort, support, and energy return that runners have come to expect from the Ultraboost line.
But what exactly makes the Ultraboost 21 stand out? Let’s take a closer look at some of the key features and technologies that contribute to the shoe’s popularity.
A Plush, Foot-Hugging Upper
The newly engineered upper on the Ultraboost 21 wraps the foot in adaptive support and unmatched comfort. Adidas utilized a high-stretch woven material that moves and expands with your foot as you run. Targeted patches of a unique TFP material offer strategic support in areas most needed, like the midfoot and heel. The result is a shoe that feels like a “second skin” as one reviewer described it.
Gone is the plastic cage that appeared on previous Ultraboost models. This allows for a more seamless, sock-like fit. The minimal layered overlays across the top of the foot also reduce irritation that could occur during longer runs. Reviewers consistently praise the Ultraboost 21’s upper for its balance of stretch, structure, and breathability.
Unmatched Energy Return from Boost Midsole
The Boost midsole foam remains the star of the show on the Ultraboost 21. Boost technology provides a springy, responsive ride unmatched by competitor foams like Nike’s React or Saucony’s PWRRUN. The particles that make up Boost foam absorb impact shock and immediately return that energy back to the runner. Testers remark how the Ultraboost 21 feels fast and propulsive, even during easy paced runs.
Adidas optimized the midsole by varying the density in certain areas. The heel is slightly softer to improve cushioning on impact. Firmer foam under the forefoot and midfoot ensures you get ample pop off the ground during toe-off. The result is a balanced ride that provides both cushioning and rebound.
Outsole Engineered for Durability and Traction
The Continental branded rubber outsole equips the Ultraboost 21 with the traction needed for varied terrain. Flex grooves under the forefoot promote a smooth transition through the gait cycle. Durable rubber covers high-impact zones on the heel and toe to prevent excess wear over time.
While not a full-blown trail shoe, reviewers report the Ultraboost grips well on dry trails and light gravel. The outsole strikes a balance between sufficient traction and a smooth ride on roads. After all, the Ultraboost still leans more towards a road running shoe.
Sci-Fi Inspired Aesthetic
Beyond performance features, the Ultraboost 21 simply looks fast and sleek. For this model, Adidas took inspiration from spacecraft design and sci-fi themes. Examples include the unique “engine” styled heel on some color options and the celestial and space-themed patterns printed on certain versions.
The result is a modern, eye-catching aesthetic that runners love to be seen in. The Ultraboost 21 comes in versatile neutral colorways like Core Black and Cloud White that can be incorporated into any runner’s rotation.
Supple Step-In Comfort
“Slipper-like comfort” is a phrase seen across Ultraboost 21 reviews, and rightly so. The plush collar pads the Achilles while the stretchy knit upper envelops the midfoot snugly but without pressure. There is no stiff break-in period – the Ultraboost 21 feels plush right out of the box.
The Ortholite sockliner adds an extra dose of underfoot cushioning and moisture wicking. Reinforced eyelets ensure a smooth step-in feel over hundreds of miles. For runners wanting comfort right from that first try-on, the Ultraboost 21 delivers.
Performance for Any Runner
Another key factor in the Ultraboost’s popularity is its versatility as a daily training shoe. The responsive cushioning works for easy recovery jogs, yet the Ultraboost also provides the snappy feedback needed for speedwork or tempo runs. It’s a shoe built for any runner at any level.
The generous, balanced cushioning suits most foot types, from neutral pronators to mild overpronators. The knit upper accommodates wider feet better than previous versions. Simply put, the Ultraboost 21 is a dependable choice no matter your running style or preference.
With significant updates that improve upon an already beloved shoe, it’s no wonder the Adidas Ultraboost 21 remains a top choice for runners. If you’re looking for your next daily trainer, the Ultraboost 21 brings together plush comfort, endless energy return, and a bold new look that is sure to turn heads on your next run.
Ultraboost 21 Vs. Ultraboost 20 – How Do They Compare?
With each new Ultraboost model, Adidas aims to iterate and improve upon the previous version. So how does the Ultraboost 21 stack up against its predecessor, the popular Ultraboost 20?
While the Ultraboost 21 retains the same general DNA, it does feature some key performance upgrades. Let’s look at some of the biggest differences.
Lighter and More Breathable Upper
The most noticeable change on the Ultraboost 21 is the reengineered upper. Adidas trimmed down the materials to shed weight compared to the Ultraboost 20. Strategically placed textured overlays provide structure only where needed.
The result is a more breathable and flexible upper. Testers note the Ultraboost 21 runs cooler than prior versions, especially during hot summer miles. The upper adapts better to the shape of your foot for fewer irritating hot spots.
Smoother Heel for Achilles Comfort
The Ultraboost 21 also switched to a lower heel profile with plenty of Achilles padding. Previous models had a more protruding heel that could rub and irritate the Achilles, especially during faster paced runs. Reviewers consistently praise the Ultraboost 21’s heel design for eliminating that irritation.
The sculpted heel cup provides a locked-in feel at the rearfoot. Adidas found a way to improve comfort while still delivering a secure fit in the back.
Sleeker, Street-Style Look
Gone is the midfoot plastic cage found on the Ultraboost 20. This gives the 21 a sleeker side profile that functions better as an everyday sneaker. The simplified styling helps the Ultraboost 21 stand out from its predecessor.
Flashy color options like the Lego-inspired blocks on the Ultraboost 21 DNA model also deliver bold street-style aesthetics. The Ultraboost continues to evolve into both a performance running shoe and fashionable lifestyle sneaker.
Outsole Durability Remains a Question
One area where the Ultraboost 21 still struggles a bit is outsole durability, similar to the 20. The Continental rubber still wears down quicker than outsoles from other top brands like Saucony or New Balance. Heavier runners and those logging high weekly miles will notice faster breakdown in the heel and forefoot.
The exposed Boost foam also continues to be a dirt magnet and tricky to keep clean. This issue seems inherent to Boost technology in general, though, and not specific to the 21.
Overall, the Ultraboost 21 improves upon the previous edition in the key areas runners care about most – responsiveness, comfort, fit, and style. It retains the signature Ultraboost qualities while evolving the upper and design. Any fan of the Ultraboost line would be wise to try the 21.
Key Features That Set the Ultraboost 21 Apart
As we’ve covered, the Ultraboost 21 brings some significant updates to take performance to the next level. Let’s highlight some of the key features that set the Ultraboost 21 apart in the running shoe world.
LEP Torsion System for Added Stability
A big part of the Ultraboost’s popularity is its balanced cushioning for all runner types. To provide a touch more guidance for overpronators, the 21 added the LEP Torsion System in the midfoot. This thermoplastic component adds midfoot structure without being overly controlling.
Reviewers note it gives the Ultraboost 21 a more stable feel compared to the floaty softness of the Ultraboost 20. So for runners needing just a touch more support, the Ultraboost 21 has you covered.
Increased Energy Return from Optimized Foam
While still using Adidas’ renowned Boost midsole foam, the pellets were strategically tuned on the Ultraboost 21. The foam is softer in the heel to improve cushioning, transitioning to firmer pellets in the forefoot for extra propulsion.
Testers consistently praise the responsive, bouncy sensation of the updated midsole. The Ultraboost 21 offers energy return on par with the best foams from Saucony or Nike while retaining its plush comfort.
Adaptive Torsion Spring for Propulsion
Working in conjunction with the LEP system, the Ultraboost 21 uses an Adaptive Torsion Spring through the midfoot. This allows the forefoot and midfoot to operate independently for smoother transitions. It also provides extra snap as you toe-off for increased efficiency.
A common praise among testers is how the Ultraboost 21 “seems to run the miles for you.” This lightweight propulsion system plays a key role in that effortless feel.
Grippy Continental Rubber Outsole
Continental rubber has a legendary reputation for traction and durability in the world of high-performance tires. Adidas partnered with the German company to create a grippy rubber outsole optimized for wet and dry conditions.
Not only does this provide great traction, it holds up well over miles. Rubber protects the high abrasion zones in the heel and forefoot to maintain the pleasant ride of the Boost foam.
Through tuned cushioning, torsion stability, and a grippy outsole, the Ultraboost 21 stands out by optimizing features that matter most – comfort, responsiveness, and support. It exemplifies the continual innovation that makes the Ultraboost lineup so popular year after year.
Ultraboost 21 Upper – Engineered For Support and Comfort
The upper of a running shoe plays a critical role in fit, breathability, and foot-holding security. Adidas obsessed over the Ultraboost 21’s upper to strike the ideal blend of support and unmatched comfort.
Strategic Overlays for Structure
The Primeknit upper provides that signature stretchy sock-like fit. Adidas wove in targeted high-density yarn overlays in areas that need extra support, like the midfoot and heel. This allows flexibility where you want it while retaining structure around the foot.
These reinforcements play a big role in providing a dialed-in fit for narrower feet. Reviewers mention the Ultraboost 21 hugs the midfoot snugly without squeezing or pressure points.
Adaptive Fit and Forgiving Comfort
That adaptable Primeknit upper blankets the foot in plush breathable comfort. The yarns expand and contract as your foot moves and swells, eliminating painful hot spots or blister points. One tester said it’s like “slippers you can run in.”
The Ultraboost 21 also uses stretch web lacing for a customizable fit across the midfoot. This system integrates with the Forgedframe heel counter for security that adapts to your foot.
Targeted Use of TFP Transparent Film
Adidas strategically placed strips of a transparent TFP film in areas needing extra midfoot lockdown and support. This reinforces the lacing system and midfoot overlays for a truly tailored fit.
Yet it doesn’t create pressure. Reviewers are amazed at how it disappears against the foot during runs. By zeroing in on targeted support zones, the Ultraboost 21 upper achieves the “second skin” feel runners love.
Plush, Irritation-Free Heel
The low-cut heel opening features plenty of padding around the Achilles collar. This along with the minimal heel counter eliminates abrasion and hot spots, especially for heel strikers. Previous Ultraboost versions were known for Achilles irritation, but the 21 addressed that issue.
All around, Adidas tuned the Ultraboost 21 upper for foot-hugging comfort that adapts on the run. It melds softness and forgiveness with zoned structure in all the right places.