History of Boost:
“Wait, Adidas makes running shoes?” Oh yes, the thought of many runners the past decade or so until the landmark year of 2012. This was the year that Adidas fist unveiled their “Boost” technology and ultimately gave new life to their running shoes (metaphorically and quite literally!). Ok so what is Boost you might ask? Well you can thank some chemist in Germany (here is a good article giving a little history (LINK); who designed this midsole material. The full name of TPU Boost being “Thermoplastic polyurethane” or TPU for short, is actually a type of plastic (as is EVA – “ethyl vinyl acetate” the common midsole material of many running shoes). What separates TPU from EVA and other midsole foams is that TPU are little spherical units that are globbed together to form a slab of midsole material. You will notice when looking at the midsole of Adidas’ running shoes how it doesn’t have a nice smooth finish. This is because as I stated above the material is welded together with many individual units that work together as one – pretty cool eh? EVA and other midsole materials on the other hand are one continuous piece(s)/mold of midsole material formed into a shape. This can be accomplished in many ways. If you want to really geek out over this here’s a link to a site that does a decent job explaining the different type of running shoe midsole technologies (LINK). Ok so enough rambling on that and onto the review of the Adidas Adizero Adios Boost 3!
Ah yes the Adidas Adizero Adios Boost 3. The pinnacle of what a long distance racing flat should be! After all, this is the shoe that has been and is worn by some of the fastest long distance racers of all time. If you are like me and have been watching the Olympics this year at Rio, you will have noticed that both men and women in the marathon had several individuals rocking the Adios Boost 3. It is a damn fine shoe and I think you will enjoy this review.
I would like to first say that out of all the running shoe companies, Adidas does the best job in the looks department, especially if you are like me and enjoy that “retro” running shoe look. These shoes will NOT be mistaken for a lifestyle shoe (a lot of Nike and New Balance running shoes anyone?). These look fast with the bright obnoxious colorways available, flashy utilization of the Adidas logo on the sides, and streamlined appearance. I am still waiting for another Purple version of this shoe…. that would make me give this shoe an A+ on the looks department… a guy can dream right? Editor's Note: the purple Adios Boost 2 was awesome....)
(thanks to Running Warehouse®)
Heel to Toe Drop – 23mm heel 13mm forefoot
Weight – 7.9oz men’s size 9, 7.3oz women’s size 8
Price – $140
Colorways –Red/White/Black & White/Red MEN, Sun/White/Red & White/Red WOMEN
(Image obtained from www.runningwarehouse.com)
Fit and Upper:
Adidas does a remarkable job at the design aspect of the shoe; both from an aesthetic and functional view point. One must respect that German engineering. In other words, Adidas does not overlook the fine details. First thing to know about a majority of the Adidas running shoes though are that their lasts (shape of the shoe) run narrow. As you will learn from more of my reviews I have very narrow feet so keep that in mind if you have an average to wider foot. Now granted these are racing flats and should fit like a glove as you don’t want to have to worry about your shoes sloshing around on race day. The midfoot of these is adequate up to medium width feet and the upper stretches nicely with no weird pinching on one’s forefoot or toes. NOTE these are nowhere near as narrow of a last as the Brooks Hyperion. The upper is a woven mesh material that has fantastic breathability and you should not experience any hot spots if you have a medium to narrow foot and purchase the correct size. (I cannot speak on how they will feel in colder weather, but again if you are using these for racing you will have your feet warming up no problem). Running sockless may not be the wisest choice, as the mesh feels a bit scratchy against bare skin. You will also note the placement of the Adidas logo on the sides of the shoe; which contributes to the function of the fit of the shoe. These stripes help act as a midfoot wrap and hold the foot securely to the sole unit of the shoe so that you can run confidently when you are picking up the pace. There is not much in the terms of overlays, but there is some felt on the mesh that adds a nice look to the shoe – giving it that retro running shoe appearance, as well as some nice reflective material so your competition and/or people driving their cars will see you. The heel counter is rigid but not overly so. This is important because it is very comfortable against the heel of your foot where your Achilles attaches to the posterior calcaneus (heel bone) giving you heel security and gives some inherent stability for your gait cycle. In other words, the back part of your foot is suppose to be rigid and holding it in place allows your foot to get more energy on toe off with no wasted energy trying to stabilize the rear part of the foot. Oh and one more thing, I appreciate that Adidas did not skimp out on using a high quality sock liner and the tongue is perfect. It’s the little things that can make all the difference!
Editor's Note: I have a wider foot than Nathaniel and will say that the forefoot is DEFINITELY wider than the Adios Boost 2. However, while the width of the upper across the metatarsals is wider, the end of the shoe tapers quicker than previous versions. For some that may make the shoe feel especially narrow, so be aware of this before try them. The upper, being more pliable than previous versions, does stretch out a little after breaking in so the feeling may go away. Overall a very comfortable upper.
Midsole and Ride:
So we finally make it to the best part of this shoe – the ride! Here in lies the magic of Boost – very thin slab of foam (approximately 13mm in the forefoot!), yet you get tremendous responsiveness and PROTECTION simultaneously. Boost is supposedly more resistant to decompression, more resistant to temperature changes, has a higher dampening affect (decreasing vertical forces), and a higher rebound (there is some scientific studies in the literature if you feel like some light reading). Yes I know this all sounds gimmicky, but it works. Remember, the Boost sole unit is made up of hundreds of balls of TPU pellets smooshed together; which means that the midsole is actually hundreds of individual units working together. The midsole is NOT one continuous piece of foam like many of the other midsole technologies. The other bi-product of this is that it allows the Boost to behave like a school of fish; where no matter how your foot lands, the TPU pellets have some wiggle room to move around and give you a customized ride. Weird analogy I know, but that’s how I think of it
Note above the plastic midfoot piece. This acts as a stabilizer for the midfoot and acts as a chassis for the TPU Boost pellets.
Editor's Note: The more compliant a material, the more it will deform upon impact and the less it will be able to resist the many different directions of force that the body produces while interacting with the ground (ground reaction forces being among them). Because the body usually utilizes groups of muscles for motion, forces are never perfectly produced in one plane (sagittal, frontal or transverse) and instead are produced in a variety of directions. So a softer shoe thus becomes a more unstable shoe. The body is more responsible for stabilizing upon impact rather than absorbing shock, which is done by the underfoot material... (or so the body thinks sometimes with soft and thin midsoles) because those ground reaction forces are actually really important. They activate prioprioceptive receptors in the joints that activate the muscles to fire and help load the incoming forces rather than only the joints themselves. So that is why it is important in a softer shoe to have some kind of stabilizing element like the midfoot torsion system to keep some degree of stability (not talking about posting). You always want a balance. Too firm a surface? The body has to focus solely on absorbing shock rather than pushing off because it has to protective itself. Too soft a surface? The body has to focus on stabilizing the limbs to prevent ligament or soft tissue sprains or strains to keep from collapsing. The balance is important.
The one thing I wish though is that this plastic unit extended further into the forefoot. If you were to look at other racing flats (such as the GoMeb Speed (REVIEW), the non-Boost Adidas Adios, Salming Race, New Balance 1600) is the use of a plastic or carbon fiber unit that that extends into the forefoot and acts as a lever. Why is this useful? Well what this does is it allows the maximal use of the Windlass affect – i.e. taking the energy collected in the foot and allowing it to SNAP forward as a propulsive unit. The Adios 3 is lacking this full potential in my opinion, but it still manages to be a very responsive ride. Again one could argue that this is a long distance racing flat and that many of the types of flats I mentioned are shorter distance racers. This is true, but Matt Klein will tell you that if you experience the extended plastic/carbon fiber unit in a racing flat you will appreciate the difference.
Editor's Note (again): One of my favorite aspects of many Adidas Racing shoes is the extended forefoot torsion system in the Takumi Sen 1 and 2, Takumi Ren 1 and 2 and Adios 1, 2, Boost 1, 2 and 3. It is an extension of the midfoot torsion system that traveled in three stiff track spike plate like prongs into and through the forefoot. This allows amazing energy transfer from landing to toe-off by complimenting the action of force transference forward by the plantar fascia (when the plantar fascia is utilized and balanced correctly with proper muscular and foot function. That's another post for another day). It used to feel like you were wearing a track spike for the road and made pushing off in these shoes amazing. That has been toned down and made more flexible (per Sam Winebaum of RoadTrailRun) in the Adios Boost 3, likely to address the lack of forefoot cushioning (complaints seen of many individuals of previous versions) along with the newly lugged forefoot outsole. These lugs act like pistons, similar to Nike's waffle outsoles in previous version of the Pegasus and other trainers. They add additional cushioning and protection for sure in the forefoot and some degree of additional propulsion. In my humble opinion, they do not create as good propulsion as the previously stiff extended forefoot torsion system prongs. While I am happy that the system is still there, Adidas seems to be toning down this aspect and even going so far as to remove it completely from the Ren and Sen 3. I really hope Adidas adds the previous stiffness back to give more structure and speed to the forefoot boost.
Ok I know I didn’t discuss the outsole for ride, because I wanted to save it for here. Again, Adidas nails it in not ignoring the details in the design and function of their shoes. The use of Continental Rubber (yes the stuff of race cars) is the rubber covering the bottom of this shoe. And boy is it grippy! I have never once had an issue with traction and the durability is insane along with the Boost material. I even used these in a ½ marathon trail race recently and they held their own fairly well on some lose ground Honestly, I already have 350ish miles on my pair and they barely look worn. That is why I didn’t balk at the $140 price tag as you will get your money’s worth and then some.
Areas for Improvement:
A return of the previously stiff forefoot torsion system to give an even snappier ride. Oh and I would like to see this shoe drop another 0.5oz if possible (difficult as Boost material is heavier than the other types of midsole material).
Editor's Note: I agree with Nathaniel. The stiff extended forefoot torsion was a classic Adidas Racing shoe feature. The loss of this in the Ren and Sen and toning down in the Adios Boost 3 have definitely detracted from the beautiful rides I once knew. These are still great racing shoes, but I hope they add this back in to create more structure and add more speed back to these shoes. Athletes are still running incredible times in these shoes but I still think they could be better.
If you are in the market for a long distance racer, have a medium to narrow foot, and a shoe that can double for tempo and speed days, look no further. This show was made to go the distance and make you feel fast when accomplishing this. The durability of this shoe is outstanding for a racing flat and the $140 price tag is worth it. I recommend using this for ½ marathon to full marathon road races. You can use these for trails, but I would avoid using them on technical trail races as they will not give you the level of protection or grip that you need for steep climbs and descents. If you haven’t given Adidas running shoes a look, now’s the time to feel the magic of their shoes.
These opinions are my own, these were a personal purchase, and I received no monetary compensation for this review. -Dr. Kolias, DVM, MPH
Editors Note: As always, the views presented on this blog belong to myself or the selected few who contribute to these posts). My blog should not and does not serve as a replacement for seeking professional medical care. If you are currently injured or concerned about an injury, please see your local running physical therapist or medical professional.
Thanks for reading and don't forget to tack on!
-Dr. Klein, DPT and Dr. Kolias, DVM, MPH