NIKE Men's Air Zoom Structure 21 Running Shoes

Product Information

The Streak 6 is a lightweight Nike model fitting for shorter road races and distances for up to a half marathon. We had our work cut out for us last year because the Odyssey 2 was the perfect upgrade path from the Structure. This year, the Odyssey is gone so the only way is down. If you don’t require Structure levels of support, then you should look up the Nike Zoom Span 2. In his experience the older versions with the medial cage held up much better than the Dynamic Support in the 20 (and 21), which compressed inward as the miles were added, while the outsole durability remained the same despite its overhaul in structure.

Structure 21 rides very similarly to the ASICS GT-1000 6, with a bit more flexibility in toebox upper fit; the heel fit also gives a touch more room. So all in all, the fit is closest to ASICS’ GT-2000 series. The Structure 21 has a softer interior feel than the 18, 19, and 20 due to the updated mesh which also has better breathability. RIDE QUALITY AND BEHAVIOR The inner outsole is populated with a colony of pentagonal lugs. The rearfoot has a shallow cavity exposing the midsole foam; this extends to a transition groove which splits the outsole longitudinally. The forefoot has an internal Nike Zoom Air bag. The Nike Structure is all about balance. The upper has smooth interiors and fits well. The inner strapping system which was re-introduced on the Structure 20 finds its way into the 21, and that’s a good thing. The Flywire cords are restricted to the rearfoot, and this means that the midfoot is secured entirely by the straps.Expect 400 miles of life from the Structure 21, with the wear and tear of the midsole cushioning and outsole happening in a gradual fashion. UPPER FIT AND FEEL I prefer the Structure 24 because I’m not a fan of prominent arches in running shoes. The Structure 24 felt like more of a neutral shoe which was supportive. The 25 feels like a stability trainer. In case if you found the last year’s Structure 20’s ride to be hard on your feet, consider the list of alternatives at the end of this review. PROS AND CONS When it comes to support, the Structure 25 is currently the most supportive trainer in the Nike lineup. I’m a mild overpronator with flat feet and I find it stable but the prominent arch is a bit too overbearing. I think it will provide enough support for most overpronators but it’s more suited to runners with high arches.

The excessive outwards bias or lean of the older Structures (17, 19) is no longer present on the 21. The rearfoot has a bit of an outer bias due to the midsole groove and the beveled heel, but only slightly so.

Nike Zoom Structure 21 Price Comparison

The lacing panel and the Flywire areas are now reinforced with a thinner and transparent laminate which also helps reduce weight. This workout session cemented in my mind that Structure is more suited for mid to long distance runs than speedwork and that the more loose heel really does bother me. A lower drop seems to encourage runners onto their toes while at the same time limits the range of motion of the Achilles. The Structure 25 won’t be staying in my rotation. It’s a decent running shoe with a good price but I’m not a fan of the prominent arch because of my flat feet. I prefer other stability features like a wide base or a plate. I also find that it has a flat, boring ride like a shoe from 6 years ago.