Out of the ten shoes in this lineup, the Adidas Ultraboost X is by far the most different. Even when compared to the funky, maximalist HOKA ONE ONE Bondi 5, the Ultraboost has a design we've frankly never seen before. The upper is similar to a stretchy, extremely breathable sock, sheltered by a hard plastic shell with laces for support. The arch is completely disconnected from the sole, which is thick, extremely cushy, and light. It was difficult to compare this shoe to its competitors because of how different it is, but overall we ended up thinking it had amazing landing comfort, good responsiveness, and was moderately comfortable. We do recommend, however, that you try on this model in a store before purchasing to see if its wild design is suited to your style and needs.
Adidas Ultraboost X Review
Cons: Floating arch is uncomfortable, not supportive
Our Analysis and Test Results
The Ultraboost X failed to win an award for its lack of stability and upper comfort, but its responsive, cushy sole may appeal to the buyer looking for a trendy alternative to the usual traditional shoe style.
Below, we can see why the Ultraboost didn't win an award, but it still has many great qualities.
The Ultraboost X has a distinctly comfortable yet very different landing. We liked the soft foam of the sole, and while some of our testers like the snug fit on their arches, overall we docked it points for not being as widely appealing.
One one hand, we think the sole is surprisingly comfortable and has a very soft landing. There is also quite a bit of cushioning when compared to its competitors, and we awarded it a higher score for this.
The floating arch, on the other hand, is a feature that we have mixed feelings about. It's hard to separate upper and landing comfort when reviewing this shoe because of how closely linked they are. The arch is disconnected from the sole, and the upper hugs the bottom of the foot and gives ample arch support. We think that this may appeal to some buyers, as it did with some of our reviewers with high arches, but overall we didn't award it as high of a score as other shoes because of its lack of universal appeal. We suggest trying it on, however, if you're drawn to this shoe because we did find its landing soft and comfortable, and in this category the Ultraboost could easily compete with our favorite models, like the Brooks Adrenaline GTS and Ghost.
Adidas designed this shoe to be highly responsive, and we have to agree. Despite a lot of cushioning, our steps were bouncy and quick, helping to identify the potential niche area of this different product.
Our favorite bouncy shoe was the Nike Air Zoom Pegasus 35, and the Ultraboost gives it a run for its money. Along with our Editors' Choice Award winner, the Adrenaline, these three shoes get you going during speed workouts or races. Despite its other qualities that we didn't like as much, we can't deny its highly responsive design.
The UltraBoost X's design is one of the most unique that we've ever seen on a running shoe. With an upper that floats, detached, above the sole, we had no idea what to make of this shoe initially, but soon found a breathable upper that was hard to compare directly to its competitors.
Unlike every other shoe in this review, the UltraBoost X doesn't have a tongue. It is basically a super stretchy sock with a plastic cage. The sock sits very snugly against the foot and arch. We wore this shoe without a sock because of the snug fit, and despite initial trepidation, we soon started to actually like it.
The sock-like upper is very breathable despite its tight fit. The heel is guarded by an impenetrable plastic cage, but the inner sock has ample cushioning. It's difficult to compare this shoe to its competitors because the design is so different, and while we still preferred a more traditional design with ample cushioning throughout, we can't deny that the UltraBoost X is intriguing. While some shoes in this review scored lower for lack of cushioning in the heel and tongue, we asked ourselves how easy it was to forget we even have the shoe on for this scoring metric. The UltraBoost was surprisingly comfortable, the way walking around the house in your socks is, but we still preferred a nice, plush shoe like any one in the Brooks trio we reviewed.
Adidas markets this shoe to runners with high arches, and we can see why. With an arch that fits snugly and floats above the sole, this could be an interesting model to try out if arch discomfort often plagues you. Otherwise, the UltraBoost lacked some of the stability-focused design features of its competitors, earning it a low score in this category.
With only a little bit of laminated material in the midfoot, this shoe provides almost no support. The material is so soft that, despite the cage, there is not much to help keep your stride in good form. There is a bit of reinforcement in the toe, but nothing compared to the burly sidewalls of the Brooks Glycerin. The hard cage allows for some stability, but we found it to have the same less-than-stellar performance as the Altra Escalante, whose soft material did little to protect our feet.
At 8.4 ounces per shoe, the Ultraboost is right in the middle of our lineup. We found this surprising because of its mega-light upper, but the chunky sole makes up for it.
The lightest shoes in this review are the Escalante and New Balance Fresh Foam Zante, at 7.1 and 7.4 ounces respectively; the heaviest is the ASICS GEL-Cumulus at 9.4. While we always appreciate saving ounces, we do believe that weight should be a secondary factor when judging running shoes as long as the weight is near the middle. For the Ultraboost, whose weight is solidly average, we recommend using comfort and fit to make your decision before wondering if you'll notice the slight discrepancy in a few ounces.
The Ultraboost's average weight puts it in the running for an all-around, everyday model, and its closest competitors are the Nike Air Zoom Pegasus and Brooks Adrenaline GTS, both of which have their own strengths in comfort and responsiveness.
With little lateral stability but a healthy dose of arch support, the UltraBoost makes for better speed than distance. The tight fit and ample responsiveness support its design as a great partner for short, fast workouts. We wouldn't recommend this as a race or long-slow distance shoe.
At $180, the Ultraboost is the most expensive model in this review by $30. Because of its unique design, we're unlikely to recommend this shoe to the average runner looking for something to get their weekly mileage in. We're much more likely to recommend the Air Zoom Pegasus for speed workouts, however, because it is both more affordable and more comfortable.
With such a different construction, the Ultraboost X was certainly worth a try. We appreciated its snug fit and responsive sole that was pretty comfortable. However, Adidas' new design concept was just a little too out-there to be universally appealing, and we ultimately couldn't award it one of our top spots despite thinking that it may make a great purchase for many athletes.
— Lauren DeLaunay