It’s fair to say that adidas’s boost foam technology was a significant leap forward in the running industry, brands suddenly had to deliver new technology in a bigger way; they all had their named products and different selling points, but boost left a few floundering.
That’s not the case now with the recent development of ZoomX and React (Nike), Everrun (Saucony), FreshFoam (New Balance) and many more, plus it has recently felt like adidas have ever so slightly lost their way with their benchmark running products.
The new Solarboost seems to counter this trend, a trainer that is built out of the need for a do it all running shoe focused purely on performace. Boost foam is proven to work, so that remains unchanged, but the rest of the shoe saw the designers and technicians taking it back to the drawing board.
Having spent some time at adidas HQ discussing the trainer and crucially running in them, here is what it has to offer runners.
Exploded shoe to the left shows how the guide rail and torsion system is integrated into the sole.
This is the new part of the shoe and there are some integral changes in appearance and performance. Using something that adidas call Tailored Fibre Placement (TFP), a stitching process that allows for data obtained from pressure mapping stresses and forces placed on the shoes when in motion to add or remove structural integrity, the shoe upper is totally different to anything else previously made by adidas. The result is a reassuring structure around the top of the foot that helps hold the foot into the re-jigged heel counter (more on this below).
The toe box is built of a new stretch fabric that allows the foot to naturally spread but is contained in the shoe by the strips of plastic that run across the toe box (see picture below) adding necessary tension to the front of the shoe, something that knit construction sometimes fails to do. This stretch fabric extends into the tongue, which essentially acts like a gater/sock. The tongue has also been flattened and pressure mapped to make sure it works in conjunction with the upper.
Something of real note worth mentioning with the upper is that pretty much anything that can be turned into thread can be used to build the shoe (they’ve tried carbon fibre etc). This has meant that adidas’s relationship with Parley has now stepped up a gear and each Solarboost is built using recycled plastic from the sea. To what degree is to be confirmed but some is better than none so that earns them a big tick in the ethical box.
Designed to reduce pressure on the achilles, the heel of the shoe will look familiar to some but it’s been updated; the heel cuff around the ankle has been reduced significantly to remove bulk, the heel counter has been widened to allow more room for achilles movement and it’s been designed to work in line with the new guide rail that runs the length of the shoe, laterally and medially. The Torsion system also adds a small degree of structure to the heel (the orange pyramid of plastic in the picture below) that is designed to help those that heel strike for a more progressive transition through the gait cycle.
This guide rail (the turquoise and orange plastic strip around the edge of the shoe; see above) though a small detail is a crucial one as when combined with the new upper and heel counter, adds support to the shoe, reducing the amount of lateral movement of the foot in the shoe. The bulk of the rail starts at the heel and runs into the instep of the foot, before tailoring off into the forefoot so as not to interfere with that all-important foot spread.
Not a pure boost sole, the solar is only 85% boost but taking into account the torsion system that helps stabilise the shoe during foot strike and the guide rail that extends into the toes (all the orange bits in the pic above), this easily accounts for that 15% and the purpose it serves. Teaming up again with Continental for traction, the stretch web outsole is formed to best suit the mechanics of running and does a great job of gripping throughout the foot strike. No complaints here for grip.
So how does all this translate when out on the move? Responsive would be the best word for it. The shoe feels stable on the foot and this is mainly down to the guide/energy rail doing a great job of adding just the right amount of stability, especially laterally, without being overbearing. Whereas many shoes have your foot sitting on top of the sole and held in place by the upper, this shoe feels like it cups the rear of the foot, the rails allowing the foot to rest into the shoe rather than on top. Though often an issue for those with wide feet, like myself, this doesn’t seem to be the case here; again the shoe is reassuring rather than controlling, the regulated stretch of the toe box allowing the foot to spread but the upper, laces and heel counter hugging the rest of the foot (in a friendly way, not a bear way).
This feeling of fit helps improve the feeling of connection with the shoe, even minor discourse between foot and shoe often leads to discomfort and a less enjoyable experience as you have to garrote your foot with the laces or grip with your toes. Also, comfort goes a long way in tricking the brain into forgetting about your shoes, which is the best possible outcome for any runner. The only initial point of concern was the tongue as it does feel more rigid and fixed than other shoes, especially as it surrounds the whole foot, but it sits comfortably atop the foot and actually serves a purpose rather than just filling the gap between the laces.
Due to the reported performance attributes of the foam, the solarboost responds to some energy being put through them and when running at pace, the shoe feels lively. The slight rocker profile means that you’re naturally put onto your toes when cadence is quick, but the shoes are just at home on those slower runs, being significantly cushioned. As for suited distances, I am 188cm (6' 2"), 85kg (13.3 stone) and have an average cadence of 170 and would wear these for 10K races through to marathons, but they’re probably a bit big for a 5K race shoe (great for a leisurely 5K however). Adidas describe them as a long distance shoe and neutral shoe and if they suit your needs, there's nothing to stop those inclined to running as far as the shoe will take them.
There aren’t that many to be downsides to the Solarboost to be honest; however the new upper is less breathable so on hot days the foot felt a little warmer than normal, but it wasn’t a big issue. The way the TFP upper is bonded to the tongue means that those who like to spread the laces wide, for whatever reason, won’t be able to. Again, not a big issue as the shoe is designed for the upper to fit as one piece, but that won’t be everyone’s taste.
At £139.99, they’re not the most expensive on the market either, especially for what appears to be a versatile shoe. Its closest competitor when placed on the sale wall would probably be its older brother, the Ultraboost, but it’s an easy choice really; you either want a boost shoe with or without stabilising features (we're not talking structure like the ST range) and if that’s the case, any shoe that offers that little bit extra to aid performance, gets the nod.
The adidas Solarboost is available to pre-order via the adidas site and retails for £139.99. It goes on sale 17th May.