Let’s go to 2013 for a moment: in that year adidas introduced a shoe-the Energy BOOST-that for the first time introduced a breakthrough element to the running world. Today the English expression “disruptive” is often used to mean something that changes the rules of the game, subverting them or moving the action into a new dimension. That year adidas did something similar.
Up to that point, shoes consisted of an EVA midsole and upper. From that year on, one of these two elements changed: in fact, adidas introduced BOOST, a brand new compound with never-before-seen elastic and mechanical properties. In the end, a shoe is made up of a few elements: simplifying, it consists of an upper (which wraps around the foot) mounted firmly on a midsole. In 2013, adidas decided that its design efforts should focus on the latter component. And it changed the rules of the game, giving a very important boost to the running market in general.
This lengthy foreword is necessary, for several reasons: to give credit to the German house and also, eight years later, to take stock of the situation. Since then, many other brands have developed proprietary materials to achieve state-of-the-art shoe mechanics and dynamics, and today we run in shoes that are radically different from those of 10 years ago: they are more minimalist, lighter, more balanced, and more dynamically lively and responsive.
adidas meanwhile
has arrived at version 21
of the BOOSTs, which have since begun to be called ULTRABOOST (due to the higher percentage of material present) and increasingly define themselves as their most popular model, not only in running.
It is worth specifying that “21” does not indicate the version but the year, although several versions have come and gone since that 2013.
In many ways this 21 is the state of the art of BOOST technology but it is also the starting point of the future of this segment of running shoes, namely those dedicated to training, long runs, and comfort. By 21, in many ways, adidas is picking up the slack and going in new directions.
Maturity
BOOSTs-or ULTRABOOSTs, then-have become more and more refined over the years: the midsole compound has taken on larger and larger proportions, the upper has changed materials and workmanship, and has increasingly become a sock glued to a midsole. ULTRABOOST are the answer to the question of what is conceptual and constructive minimalism in the running shoe.
Le
ULTRABOOST 21
are the latest and most mature and complete version of that concept outlined with the Energy BOOSTs, now eight years ago: they have a wraparound and grippy upper, they have an imposing midsole in which BOOST is no longer just a layer and a thickness but is a material, a preponderant component: it is so much so that you cannot help but notice how pronounced the heel is, how much BOOST in short there is under and even around the upper, especially at the rear. ULTRABOOST 21 could be called the “Mega-ULTRABOOST.” ;)
Aesthetics
Looking at them without having worn them yet, one might think that the midsole reaches unprecedented thicknesses in the heel area: however, this is an optical illusion because in reality the upper half of the BOOST in that position does not have cushioning functions but only heel restraint. The thickness actually available is more similar to that of conventional ULTRABOOST, that is, in the range of 30 mm.
However, it is right to focus one’s attention on the heel, and I will explain why in a moment.
Returning in the
ULTRABOOST 21
the semi-transparent plastic panels that contain the lacing eyelets and are a hallmark of the ULTRABOOST design. The back shell is confirmed, ending in that characteristic “turned-up lapel” that is very useful for slipping them on and off. Finally, the wrap-around effect of the stretchy PRIMEKNIT+ upper made from PRIMEBLUE yarn, which is largely obtained by recycling plastics collected from the ocean, is also confirmed. This choice is part of a much broader context; in fact, adidas is a brand that is making a very active commitment to the environment and, as of 2024, all of its products will use recycled yarn. The German company was the first to embark on an environmental sustainability program, and now it has made its way into the entire corporate system.
For many reasons the
ULTRABOOST 21
are the state of the art in this technology, and rightly so: we are in fact talking about their most recent version and it is natural (but not expected) that it will stand in the groove of its predecessors.
Further confirmation is the care taken in the design: the linear simplicity of the upper is balanced by the intricate construction of the midsole and outsole, so much so that it is almost unfortunate that it is predominantly hidden.
In fact, the entire system includes the ULTRABOOST midsole and various inserts and panels with different functions: there’s the LEP – the new Torsion System technology – that is, the stiff fork (in red) that transmits movement and stabilizes the transition between heel and toe, giving roll stability with 15% more grip to give you an even more responsive thrust; there’s the Continental tread in four different compositions, such as the semi-transparent rubber protecting the ULTRABOOST (more wearable material) that from the heel extends up the sides to the midfoot, which in the midfoot area becomes pink rubber and at the toe splits into a gray almond panel to finally end in the black rubber toe box. A contemporary framework and almost a graphic system, however, whose function is to respond to the different stresses to which the tread and sole system is subjected. Definitely remarkable.
To close the aesthetic analysis, we cannot overlook the special color scheme dedicated to this period of great performance, in which adidas designers have combined solar red-which has always indicated performance and innovation-with the traditional black and white. Beautiful.
On the road
Then comes the time to put them on and run with them. The fit is firm and very snug, something ULTRABOOST has long accustomed us to. It is so “sock-like” and wrap-around that the lacing is only for fine adjustments, certainly not for holding the foot firmly in place. Also in this
ULTRABOOST 21
it has reached the state of the art: foot containment is perfect both in the front and thanks to the soft contoured shell in the heel. The feeling of protection and safety is impeccable. I recommend trying on a half size larger than your usual because, as they say, ULTRABOOSTs “wear small” and by dilating during the run your foot may feel a little constricted. It is enough to know in short.
I now return to the heel I mentioned earlier, because that is where the focus is-I say this perhaps exaggerating a bit-the strength of these shoes. To explain it, I have to say how I ran with it and what it felt like.
Looking at them in profile and assessing the amount of ULTRABOOST, these adidas have a lot of it on the heel (although what actually works, I mentioned earlier, is about half of what you see) and a normal amount on the forefoot. I am used to forefoot running so I did not notice a particular shoe response, in fact: they seem almost “flat” if you run in them by moving your footing far forward. Then I had the intuition: why not run heel-to-toe with it? It’s not something that comes naturally to me, and yet since I have done it, everything has changed, and it’s obvious when you think about it: the ULTRABOOST 21 is a shoe that concentrates its cushioning power on the heel, and not using it that way means penalizing it. And that’s not all: the LEP only works if the movement is transmitted longitudinally and from the posterior to the anterior, otherwise there remains only a stiffening of the midfoot that only partially stabilizes. Instead, to achieve the ULTRABOOST’s remarkable stability, you have to let them free to work as they are designed, because only then do they achieve the condition of stability that characterizes them. And I’m talking about something clearly perceptible: it feels like you’re on tracks, and their ability to go along with the movement of the foot, accompanying and enhancing it, is really perfect.
In this sense, they are shoes that need to be understood and recommended to heel runners because those with a different setup cannot make the most of them and indeed might perceive them as normal adidas with ULTRABOOST.
When you get in tune with them everything changes and they turn out to be what they are: very (very) stable and protective shoes with which to go a long way.
From here on.
As I said, the ULTRABOOST 21 are the ultimate expression of the technology from which they take their name, you can find them with the list price of € 180 and
are available now on Cisalfa Sport.
. Since 2013, other technologies have emerged on the running scene, and many of these are used by its “sisters,” such as the Adizero Adios Pro 2.0 and the Adizero Boston 10. I am talking about lighter and more responsive compounds and carbon fiber.
ULTRABOOSTs use a proven compound with unique features, such as its mechanical and elastic stability both over time and at different temperatures, but when such technological maturity is reached, it is more interesting to figure out what directions to take to evolve further. Change the ULTRABOOST or make an upgraded, lighter version? Make it work with the carbon plate? I don’t know but I imagine adidas designers are already thinking about it.
I am curious to see what this concept will become in the years to come, staying true to itself but enhancing itself: stable, protective, balanced. And increasingly Ultra.
