I hadn’t tried Adidas until last year when I won a pair of Boston Boost 5 at a local 5K. Since then I put over 600 miles on them and they became my favorite shoe. I vacillated for months about buying another pair or the Adizero 6 and recently pulled trigger at backcountry.com.
The Adidas Adizero Boost 6 weighs 8.6 ounces for a Men’s size 9 with a 10mm drop (16/26).
The biggest complaint I’ve heard about Adidas from runners is their out-of-date uppers. I was one of those people, at least talking about the previous iteration of this shoe, but that problem seems to be resolved in this update. The upper is mesh knit, seamless and breatheable, like most shoes on the market today. I wouldn’t say that the upper is anything special, but compared to the Boston Boost 5, it’s strides in the right direction and at least matches other shoes in it’s category. The fit is snug and narrow, but the stretch mesh lets your foot move just enough and doesn’t cause any pressure points. They run true to size, just expect a locked down, performance oriented fit.
The midsole is what really shines here. I have never run in a road shoe that feels this good. When you’re running slow, it feels soft, when you pick of the speed, it feels responsive. It almost seems to adapt to the specific work you’re doing. I wanted to know why and I really geeked out when I was reading about the development of Boost Foam.
Boost was developed by BASF, one of the largest chemical engineering companies out there, who has had a 30+ year relationship with Adidas. The idea for boost, actually called infinergy, came up during a coffee break. A chemist at BASF, Frank Prissok, had the idea to “foam” traditional TPU. He expanded it and increased its volume to make it lighter, softer and more resilient. What resulted was Infinergy, or “Boost” Foam. Each midsole is comprised of 2,500+ individual Infinergy beads which are then heated and steam molded together. This creates a bouncy, resilient and responsive ride. Immediately after impact the midsole springs back to it’s original shape; this rebound experience is noticeable underfoot and feels like it propels you forward. Here is a little video from BASF.
In labs tests of resilience and elasticity, Boost Foam has a rebound of 55%, compared to traditional EVA with a rebound of 37%. And unlike EVA, Boost Foam has shown not to lose resiliency under continuous loading. Boost Foam has also shown not to be adversely effected by high (104 degrees F) or low (- 4 degrees F) temperatures, so it won’t lose it’s elasticity and cushioning properties in adverse weather conditions. [Infinergy Profile].
All of this translates into an innovative midsole material with a phenomenal ride. Techno babble aside, the ride in the Boston Boost 6 is unmatched. It’s that blend of softness and responsiveness that every runner wishes they had in a shoe. The longevity of the material is also far superior to other shoes on the market. I got over 600 miles out of my Boston Boost 5 (I usually get 300 – 400 out of traditional EVA based midsoles) and the only reason I retired them is because the rubber had worn off in the right heel due to my heavy right heel strike.
This is a neutral shoe, but the midsole also features thermoplastic midfoot torsion system unit for added support at the midfoot while allowing the forefoot and rearfoot to move freely. I’m not sure if this adds anything to the ride or integrity of the shoe or if it’s beneficial for foot health; I’m one to think that these types of things are marketing gimmicks, but it’s there.
The outsole contains the same award winning, performance rubber compound that keeps you safe when driving your sports car on slick roads: Continental Rubber. Continental has perfected the rubber compound for optimal braking in sports cars, so it only makes sense that the same company would make a comparable compound that would perform well in running shoes. And I have to say: It’s pretty ridiculous (in a good way). You can feel the shoes sticking to the road underneath your feet. It really allows you to dig in and toe off without slipping, even in wet conditions. I never really took much notice of the outsole of a road shoe until I ran in these. You will immediately feel a noticeable improvement in grip on your runs. Here is a little video about the relationship between Coninental and Adidas.
I think there should, and most likely will be, some improvements made to the uppers of Adidas shoes in general, but this package is pretty spot on, albeit a little snug. I can’t think of a road shoe that rides better than the Adidas Adizero Boston 6 right now and I encourage you to give them a try if you haven’t. I took them from box to 26.2 and found myself thinking about how great my feet felt at my 24 for the first time ever. That’s saying something.
The price of these shoes, especially the Boost Ultra, are a little higher compared to other shoes in their category, but this is one of those instances where you get what you pay for. With an MSRP of $120, you’re paying for proven materials from reputable companies and a life expectancy of 600-1000 miles in a performance oriented design. I’ll pay a little extra for that.
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