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Adidas Ultraboost 21 Performance Review

adidas ultraboost 21 - feature

What You Need To Know

  • Weighs 12.77 oz. (362 g) for a US M10.5
  • Primeknit upper with yarn made from recycled plastic bottles
  • Updates include an LEP torsion system for more pop of the toe
  • If it ain’t broke, just keep BOOSTIN’ IT

THOMAS: Before I really get in the adidas Ultraboost 21, let’s put this to rest – Boost works. It isn’t the newest, it isn’t the lightest, but it works. Sort of like re-runs of The Office when you can’t find a new show to binge on. Sit back and let the staff of Dunder Mifflin Paper give you the chuckles. I don’t care what anyone says, Dwight Schrute is the glue that binds that show together.

Like Dwight, adidas still leans heavily on the expanded particles that BASF developed for them over 7 years ago. You can’t expect them to ditch the midsole compound that’s earned them so much revenue over the years.  Of course, things get a little confusing when Boost crosses over into fashion. The Yeezy crowd took to Boost like a dog to a dirty plate. Additionally, shoes like the NMD look like running shoes but are purely fashion kicks.

Things have certainly progressed since the invention of Boost – almost every company out there has a lighter and just-as-bouncy midsole foam on the market.  We definitely hear the noise from purist runners (i.e. scoffing at the Ultraboost weight and the fashion shoe aesthetic). But I’m here to tell you that the adidas Ultraboost is indeed still a running shoe.

adidas ultraboost 21 snow adidas ultraboost 21

The Good

THOMAS: Boost has always lead the way in cushioning and energy return. Where the Ultraboost needed help was in the toe-off. The Ultraboost 21 finally addresses that issue with a new LEP Torsion System. It is a flexible TPU fork that adds rigidity to your stride’s final phase, giving the runner more pop on take-off. With 6% more Boost in the midsole, the foot crash is treated to top-of-the-line comfort. The 30.5/20.5 stack height (10 mm drop) feels aggressive in the right way. The UB21 leans forward and creates a faster turnover. The shoe won’t stand in the way of faster paces when you need them.

You can feel good about the upper of the UB21. According to adidas, the “product is made with Primeblue, a high-performance recycled material made in part with Parley Ocean Plastic. 50% of the upper is textile, 75% of the textile is Primeblue yarn. No virgin polyester.” The upper is a tighter feel than most of the running shoes we review. Adidas says it is a “sock-like fit,” and they aren’t lying. The toe box stretches and can accommodate various foot shapes, but it isn’t roomy. With that much Boost underfoot, I appreciate the secure feeling of the Primeknit upper. The fit is true to size.

I almost forgot about the outsole. Continental Rubber is back with the Stretchweb outsole that is durable and grips well. The traction and surefooted feel are undeniable.

Shop Ultraboost 21 – Men Shop Ultraboost 21 – Women addas ultraboost 21

The Bad

THOMAS: You can’t escape the massive 12.77 oz/362 g weight on the Ultraboost 21 (for a men’s size 10.5). I will admit that it doesn’t feel its weight on the run. But it still tops out as probably the heaviest road shoe on the market. This next point isn’t an issue for me, but many runners complain about the lace cage on the Ultraboost. They will keep complaining cause it is back on the 21. As mentioned in the good section, the sock-like fit is going to feel restrictive to some runners. If you want lots of volume in your toebox, this is not the shoe for you. I can see my big toe through the top. The stretch of the upper helps mitigate things, but the toe box is quite shallow.

Shop Ultraboost 21 – Men Shop Ultraboost 21 – Women adidas ultraboost 21

Adidas Ultraboost 21 Conclusion

THOMAS: I admit that I have always had a soft spot for the uber cush Ultraboost line. The designs have consistently looked beautiful, and the cushion and bounce have always felt good on the run. I have taken a flamethrower to lighter shoes for being too heavy, but I have given the UB a pass. It doesn’t feel as clunky as the scale numbers. This isn’t the shoe I am going to race in. It is the trainer you use for easy runs and long slow distance runs. When you strap on a race day shoe after training in these, you’re going to feel like your flying. In that way, the Ultraboost 21 could be a great training partner that will help you build strength and keep your paces in the right zones during your training. Just because the Ultraboost 21 looks like a hypebeast shoe doesn’t mean it can’t perform. Much like Jim for Pam, my love for the Ultraboost continues.

You can pick up the adidas Ultraboost 21 for $180 by using the shop links below.

Shop Ultraboost 21 – Men Shop Ultraboost 21 – Women


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Have something to say? Leave a Comment

  1. Phil says:

    The answer to most of the negatives of the UB is the trail version. The Terrex Two Ultra Parley has a 6mm drop so the boost is balanced better, it is wide and there isn’t a lace cage. You can also get the Terrex Two Parley which is the same shoe with Lightstrike instead of the Boost.

    They would be a good review shoe for your wide footed testers.

  2. Joana says:

    Brooks are ugly as f… i feel bad when i see it.

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