We spent 10.1 hours reading reviews from experts and users. In summary, this is what runners think:

8 reasons to buy

  • Most runners agreed that the Nike Air Zoom Structure 21 had a suitably lightweight feel.
  • Several runners commended the smooth transition that this shoe offered.
  • A good number of testers felt that it had plenty of cushioning.
  • One user said that the 21st version of the Air Zoom Structure secured the foot better than its predecessor.
  • Many agreed that the style and colorways were stylish.
  • One user was appreciative of the air pockets located in the forefoot. He said that they helped propel him forward during his tempo runs.
  • A majority of the reviewers agreed that the shoe was true-to-size.
  • Several testers observed that the toe box had ample space for toe-splay.

4 reasons not to buy

  • One reviewer felt that his heel wasn’t fully supported or stabilized.
  • Another tester said that the shoe felt stiff out of the box; she wasn’t glad that she had to break it in.
  • One runner narrated that the angle of the shoe placed downward pressure on the ball of his foot, which resulted in some irritation.
  • A runner said that the insole was not as comfortable as expected.

Bottom line

The Nike Air Zoom Structure 21 is a stability road running shoe that provides moderate support. It has received much-needed upgrades to make it lighter and more comfortable to wear. The responsiveness and cushioning from the previous version have been retained. Those who are fans of the Air Zoom Structure 20 should check this one out.

Tip: read our review of Nike Air Zoom Structure 21, or see the best running shoes.



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SportsShoes, Zappos and 21 other shops don't have user reviews

Video reviews and unboxing

  • Nike has updated the upper material on the Air Zoom Structure 21. It is now made of a seamless Wrap-knit Mesh which has significantly improved on the ventilation and flexibility. The switch has also reduced the weight of the shoe.
  • The Dynamic Flywire system is still present, but they have been redesigned. More specifically, the wires have been flattened out and widened to reduce the shoe’s weight further, as well as provide a more superior midfoot lockdown compared than the previous design.
  • An internal heel counter that wraps around the Achilles was added. It serves as a structure that gives extra stability to the foot.

The Nike Air Zoom Structure 21 has standard shoe measurements. Runners will be able to get the shoe using their usual preference when it comes to length. On the other hand, the width has more options. For men, the standard, wide and extra wide variations are available. For women, the choices are narrow, standard and wide.

On the forefoot is the Duralon Blown Rubber, which is also used in the Nike Structure 22. This material is a lightweight synthetic compound that has tiny air pockets introduced during its making. These small pockets help in propelling runners forward during the toe-off phase of the running cycle. Additionally, the Duralon provides a softer underfoot feel while generating traction as the runner goes over different surfaces.

The rest of the outsole is covered by the BRS 1000 carbon rubber. BRS stands for Blue Ribbon Sports. Not only does it supply the bottom of the shoe with enough traction to take on several surfaces, but it was also designed to last long.

The 21st version of the Nike Air Zoom Structure has a supportive midsole. It is made up of both Phylon and Cushlon foams which have different densities. Phylon is a soft, core foam wedge while the Cushlon was designed to be the carrier foam, enveloping the central unit and delivering support. The combination of both foam densities makes force distribution equal, resulting in resilient cushioning that’s responsive and dynamic.

The heel part has a segmented crash pad that absorbs impact upon landing and corrects overpronation. Nike made this pad gender-specific so it can cater to specific weights. The dissipation of landing force results in a potentially more efficient transition through the gait cycle.

On the forefoot area is Nike’s Air Zoom technology. Stretched-out tensile fibers were knit inside a pressurized Nike air unit, to produce a snappy rebound. As the runner comes in contact with the ground upon impact, the fibers compress. Then, they spring back to their original state like a rubber band. This mechanic allows runners to feel a forward propulsion during the toe-off.

The upper is mainly made up of a lightweight Wrap-Knit Mesh. This mesh is composed of a network of monofilament yarns that allow air to pass through its holes, making the inside of the shoe well-ventilated. The mesh also expands quickly, catering to different foot shapes and delivering a custom in-shoe feel.

The Nike check has been embedded as an overlay to give the mesh some structural support. Aside from that, the top part of the shoe is clean and seamless.

Nike’s Dynamic Fit system is made up of widened and flattened Flywire cables, the lacing system, and the interior band around the middle of the foot. The purpose of such a design is to support the arch and to enhance the fit, making it more adaptive.

Inside is an inner mesh cleatie which delivers a soft, sock-like feel to the runner. The cleatie improves the in-shoe feel and the supportive coverage.

An internal heel counter was added to lock the heel in place minimally. It protects the Achilles from irritation, injury and impact.

Jens Jakob Andersen
Jens Jakob Andersen

Jens Jakob is a fan of short distances with a 5K PR at 15:58 minutes. Based on 35 million race results, he's among the fastest 0.2% runners. Jens Jakob previously owned a running store, when he was also a competitive runner. His work is regularly featured in The New York Times, Washington Post, BBC and the likes as well as peer-reviewed journals. Finally, he has been a guest on +30 podcasts on running.