Facts

Terrain

Road

Shoes best for road, track and light gravel. See the best road shoes.

Trail

Shoes best for trail, off road, mountains and other unstable surfaces. See the best trail shoes.

Good to know

As long as you stick to the road or path, and if you want just one running shoe, buy a road running shoe.

Arch support

Neutral / cushion / high arch

Shoes for runners who do not need any additional arch support (Around 50% of runners). Best for people with high or medium high arches. See the best neutral shoes.

Stability / overpronation / normal arch

Shoes for runners who need arch support (Around 45% of runners). Best for runners with a normal arch. See the best stability shoes.

Motion control / severe overpronation / flat feet

Shoes for runners who needs a lot of arch support. Best for runners with flat feet. See the best motion control shoes.

Good to know

- Rule of thumb: If in doubt, buy neutral shoes to avoid injuries.
- More about arch support in this video.
- Find your arch type by following steps from this video.

Daily running

Cushioned shoes for your daily easy running. Great comfort. See best shoes for daily running.

Competition

Lightweight shoes good for races, interval training, tempo runs and fartlek. Here are the best competition running shoes.

Good to know

If you want just one pair of shoes, buy a shoe for daily running.

Price
$120
Weight
Men: 10.4oz
Women: 9oz
Heel to toe drop
Men: 10mm
Women: 10mm

The height difference from the heel to the forefoot, also known as heel drop, toe spring, heel to toe spring or simply drop.

There are many opinions about what a good heel drop is. We do not recommend any in particular. Lean more in this video.

Show more facts

Road

Shoes best for road, track and light gravel. See the best road shoes.

Trail

Shoes best for trail, off road, mountains and other unstable surfaces. See the best trail shoes.

Good to know

As long as you stick to the road or path, and if you want just one running shoe, buy a road running shoe.

Neutral / cushion / high arch

Shoes for runners who does not need any additional arch support (Around 50% of runners). Best for people with high or medium high arches. See the best neutral shoes.

Stability / overpronation / normal arch

Shoes for runners who needs arch support (Around 45% of runners). Best for runners with a normal arch. See the best stability shoes.

Motion control / severe overproanation / flat feet

Shoes for runners who needs a lot of arch support. Best for runners with flat feet. See the best motion control shoes.

Good to know

- Rule of thumb: If in doubt, buy neutral shoes to avoid injuries.
- More about arch support in this video.
- Find your arch type by following steps from this video.

Daily running

Cushioned shoes for your daily easy running. Great comfort. See best shoes for daily running.

Competition

Lightweight shoes good for races, interval training, tempo runs and fartlek. Here are the best competition running shoes.

Good to know

If you want just one pair of shoes, buy a shoe for daily running.

The height difference from the heel to the forefoot, also known as heel drop, toe spring, heel to toe spring or simply drop.

There are many opinions about what a good heel drop is. We do not recommend any in particular. Lean more in this video.

Summary

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.


Rankings


Ratings

4.4 / 5 based on 15 ratings

5 star
53%
4 star
0%
3 star
20%
2 star
7%
1 star
0%

My Rating

Expert Reviews

Experts are running shoe geeks, who post reviews at youtube, directly at RunRepeat or at their own websites. Each expert is categorized from level 1 to level 5 based on expertise. See stats on expert reviews and how we calculate scores here.

Are you an expert? Apply to contribute here.

74 / 100 based on 2 expert reviews

  • 70 / 100 by Running Shoes Guru • Kristin Lassen • Level 4 expert

    The Nike Zoom Structure 21 is a shoe that’s been made lighter over its history yet still maintains a sturdy base and secure midfoot to combat the effects of overpronation in a runner’s stride.

  • 90 / 100 by Shoe Guide • Shoe Guide • Level 1 expert

    Lighter and stronger than the previous version, the Nike Air Zoom Structure 21 offers a great combination of stability, cushioning, responsiveness and durability. A shoe for everyday easy running over any distance.

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Updates to Nike Air Zoom Structure 21

  • 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.

Nike Air Zoom Structure 21 size and fit

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.

Outsole

On the forefoot is the Duralon Blown Rubber. 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.

Midsole

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.

Upper

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 bootie which delivers a soft, sock-like feel to the runner. The bootie 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.